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1 /* |
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2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #include "precompiled.hpp" |
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26 #include "memory/allocation.inline.hpp" |
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27 #include "memory/resourceArea.hpp" |
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28 #include "runtime/atomic.hpp" |
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29 #include "utilities/bitMap.inline.hpp" |
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30 #include "utilities/copy.hpp" |
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31 #include "utilities/debug.hpp" |
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32 |
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33 STATIC_ASSERT(sizeof(BitMap::bm_word_t) == BytesPerWord); // "Implementation assumption." |
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34 |
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35 typedef BitMap::bm_word_t bm_word_t; |
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36 typedef BitMap::idx_t idx_t; |
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37 |
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38 class ResourceBitMapAllocator : StackObj { |
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39 public: |
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40 bm_word_t* allocate(idx_t size_in_words) const { |
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41 return NEW_RESOURCE_ARRAY(bm_word_t, size_in_words); |
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42 } |
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43 void free(bm_word_t* map, idx_t size_in_words) const { |
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44 // Don't free resource allocated arrays. |
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45 } |
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46 }; |
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47 |
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48 class CHeapBitMapAllocator : StackObj { |
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49 MEMFLAGS _flags; |
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50 |
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51 public: |
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52 CHeapBitMapAllocator(MEMFLAGS flags) : _flags(flags) {} |
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53 bm_word_t* allocate(size_t size_in_words) const { |
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54 return ArrayAllocator<bm_word_t>::allocate(size_in_words, _flags); |
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55 } |
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56 void free(bm_word_t* map, idx_t size_in_words) const { |
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57 ArrayAllocator<bm_word_t>::free(map, size_in_words); |
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58 } |
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59 }; |
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60 |
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61 class ArenaBitMapAllocator : StackObj { |
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62 Arena* _arena; |
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63 |
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64 public: |
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65 ArenaBitMapAllocator(Arena* arena) : _arena(arena) {} |
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66 bm_word_t* allocate(idx_t size_in_words) const { |
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67 return (bm_word_t*)_arena->Amalloc(size_in_words * BytesPerWord); |
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68 } |
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69 void free(bm_word_t* map, idx_t size_in_words) const { |
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70 // ArenaBitMaps currently don't free memory. |
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71 } |
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72 }; |
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73 |
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74 template <class Allocator> |
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75 BitMap::bm_word_t* BitMap::reallocate(const Allocator& allocator, bm_word_t* old_map, idx_t old_size_in_bits, idx_t new_size_in_bits) { |
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76 size_t old_size_in_words = calc_size_in_words(old_size_in_bits); |
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77 size_t new_size_in_words = calc_size_in_words(new_size_in_bits); |
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78 |
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79 bm_word_t* map = NULL; |
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80 |
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81 if (new_size_in_words > 0) { |
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82 map = allocator.allocate(new_size_in_words); |
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83 |
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84 Copy::disjoint_words((HeapWord*)old_map, (HeapWord*) map, |
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85 MIN2(old_size_in_words, new_size_in_words)); |
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86 |
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87 if (new_size_in_words > old_size_in_words) { |
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88 clear_range_of_words(map, old_size_in_words, new_size_in_words); |
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89 } |
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90 } |
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91 |
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92 if (old_map != NULL) { |
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93 allocator.free(old_map, old_size_in_words); |
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94 } |
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95 |
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96 return map; |
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97 } |
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98 |
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99 template <class Allocator> |
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100 bm_word_t* BitMap::allocate(const Allocator& allocator, idx_t size_in_bits) { |
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101 // Reuse reallocate to ensure that the new memory is cleared. |
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102 return reallocate(allocator, NULL, 0, size_in_bits); |
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103 } |
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104 |
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105 template <class Allocator> |
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106 void BitMap::free(const Allocator& allocator, bm_word_t* map, idx_t size_in_bits) { |
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107 bm_word_t* ret = reallocate(allocator, map, size_in_bits, 0); |
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108 assert(ret == NULL, "Reallocate shouldn't have allocated"); |
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109 } |
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110 |
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111 template <class Allocator> |
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112 void BitMap::resize(const Allocator& allocator, idx_t new_size_in_bits) { |
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113 bm_word_t* new_map = reallocate(allocator, map(), size(), new_size_in_bits); |
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114 |
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115 update(new_map, new_size_in_bits); |
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116 } |
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117 |
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118 template <class Allocator> |
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119 void BitMap::initialize(const Allocator& allocator, idx_t size_in_bits) { |
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120 assert(map() == NULL, "precondition"); |
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121 assert(size() == 0, "precondition"); |
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122 |
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123 resize(allocator, size_in_bits); |
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124 } |
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125 |
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126 template <class Allocator> |
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127 void BitMap::reinitialize(const Allocator& allocator, idx_t new_size_in_bits) { |
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128 // Remove previous bits. |
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129 resize(allocator, 0); |
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130 |
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131 initialize(allocator, new_size_in_bits); |
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132 } |
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133 |
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134 ResourceBitMap::ResourceBitMap(idx_t size_in_bits) |
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135 : BitMap(allocate(ResourceBitMapAllocator(), size_in_bits), size_in_bits) { |
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136 } |
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137 |
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138 void ResourceBitMap::resize(idx_t new_size_in_bits) { |
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139 BitMap::resize(ResourceBitMapAllocator(), new_size_in_bits); |
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140 } |
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141 |
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142 void ResourceBitMap::initialize(idx_t size_in_bits) { |
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143 BitMap::initialize(ResourceBitMapAllocator(), size_in_bits); |
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144 } |
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145 |
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146 void ResourceBitMap::reinitialize(idx_t size_in_bits) { |
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147 BitMap::reinitialize(ResourceBitMapAllocator(), size_in_bits); |
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148 } |
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149 |
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150 ArenaBitMap::ArenaBitMap(Arena* arena, idx_t size_in_bits) |
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151 : BitMap(allocate(ArenaBitMapAllocator(arena), size_in_bits), size_in_bits) { |
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152 } |
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153 |
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154 CHeapBitMap::CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags) |
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155 : BitMap(allocate(CHeapBitMapAllocator(flags), size_in_bits), size_in_bits), _flags(flags) { |
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156 } |
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157 |
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158 CHeapBitMap::~CHeapBitMap() { |
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159 free(CHeapBitMapAllocator(_flags), map(), size()); |
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160 } |
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161 |
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162 void CHeapBitMap::resize(idx_t new_size_in_bits) { |
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163 BitMap::resize(CHeapBitMapAllocator(_flags), new_size_in_bits); |
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164 } |
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165 |
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166 void CHeapBitMap::initialize(idx_t size_in_bits) { |
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167 BitMap::initialize(CHeapBitMapAllocator(_flags), size_in_bits); |
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168 } |
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169 |
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170 void CHeapBitMap::reinitialize(idx_t size_in_bits) { |
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171 BitMap::reinitialize(CHeapBitMapAllocator(_flags), size_in_bits); |
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172 } |
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173 |
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174 #ifdef ASSERT |
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175 void BitMap::verify_index(idx_t index) const { |
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176 assert(index < _size, "BitMap index out of bounds"); |
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177 } |
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178 |
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179 void BitMap::verify_range(idx_t beg_index, idx_t end_index) const { |
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180 assert(beg_index <= end_index, "BitMap range error"); |
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181 // Note that [0,0) and [size,size) are both valid ranges. |
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182 if (end_index != _size) verify_index(end_index); |
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183 } |
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184 #endif // #ifdef ASSERT |
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185 |
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186 void BitMap::pretouch() { |
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187 os::pretouch_memory(word_addr(0), word_addr(size())); |
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188 } |
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189 |
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190 void BitMap::set_range_within_word(idx_t beg, idx_t end) { |
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191 // With a valid range (beg <= end), this test ensures that end != 0, as |
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192 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write. |
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193 if (beg != end) { |
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194 bm_word_t mask = inverted_bit_mask_for_range(beg, end); |
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195 *word_addr(beg) |= ~mask; |
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196 } |
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197 } |
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198 |
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199 void BitMap::clear_range_within_word(idx_t beg, idx_t end) { |
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200 // With a valid range (beg <= end), this test ensures that end != 0, as |
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201 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write. |
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202 if (beg != end) { |
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203 bm_word_t mask = inverted_bit_mask_for_range(beg, end); |
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204 *word_addr(beg) &= mask; |
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205 } |
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206 } |
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207 |
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208 void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) { |
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209 assert(value == 0 || value == 1, "0 for clear, 1 for set"); |
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210 // With a valid range (beg <= end), this test ensures that end != 0, as |
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211 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write. |
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212 if (beg != end) { |
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213 bm_word_t* pw = word_addr(beg); |
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214 bm_word_t w = *pw; |
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215 bm_word_t mr = inverted_bit_mask_for_range(beg, end); |
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216 bm_word_t nw = value ? (w | ~mr) : (w & mr); |
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217 while (true) { |
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218 bm_word_t res = Atomic::cmpxchg(nw, pw, w); |
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219 if (res == w) break; |
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220 w = res; |
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221 nw = value ? (w | ~mr) : (w & mr); |
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222 } |
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223 } |
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224 } |
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225 |
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226 void BitMap::set_range(idx_t beg, idx_t end) { |
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227 verify_range(beg, end); |
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228 |
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229 idx_t beg_full_word = word_index_round_up(beg); |
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230 idx_t end_full_word = word_index(end); |
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231 |
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232 if (beg_full_word < end_full_word) { |
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233 // The range includes at least one full word. |
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234 set_range_within_word(beg, bit_index(beg_full_word)); |
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235 set_range_of_words(beg_full_word, end_full_word); |
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236 set_range_within_word(bit_index(end_full_word), end); |
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237 } else { |
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238 // The range spans at most 2 partial words. |
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239 idx_t boundary = MIN2(bit_index(beg_full_word), end); |
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240 set_range_within_word(beg, boundary); |
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241 set_range_within_word(boundary, end); |
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242 } |
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243 } |
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244 |
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245 void BitMap::clear_range(idx_t beg, idx_t end) { |
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246 verify_range(beg, end); |
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247 |
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248 idx_t beg_full_word = word_index_round_up(beg); |
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249 idx_t end_full_word = word_index(end); |
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250 |
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251 if (beg_full_word < end_full_word) { |
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252 // The range includes at least one full word. |
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253 clear_range_within_word(beg, bit_index(beg_full_word)); |
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254 clear_range_of_words(beg_full_word, end_full_word); |
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255 clear_range_within_word(bit_index(end_full_word), end); |
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256 } else { |
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257 // The range spans at most 2 partial words. |
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258 idx_t boundary = MIN2(bit_index(beg_full_word), end); |
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259 clear_range_within_word(beg, boundary); |
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260 clear_range_within_word(boundary, end); |
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261 } |
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262 } |
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263 |
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264 void BitMap::set_large_range(idx_t beg, idx_t end) { |
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265 verify_range(beg, end); |
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266 |
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267 idx_t beg_full_word = word_index_round_up(beg); |
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268 idx_t end_full_word = word_index(end); |
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269 |
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270 assert(end_full_word - beg_full_word >= 32, |
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271 "the range must include at least 32 bytes"); |
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272 |
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273 // The range includes at least one full word. |
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274 set_range_within_word(beg, bit_index(beg_full_word)); |
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275 set_large_range_of_words(beg_full_word, end_full_word); |
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276 set_range_within_word(bit_index(end_full_word), end); |
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277 } |
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278 |
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279 void BitMap::clear_large_range(idx_t beg, idx_t end) { |
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280 verify_range(beg, end); |
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281 |
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282 idx_t beg_full_word = word_index_round_up(beg); |
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283 idx_t end_full_word = word_index(end); |
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284 |
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285 if (end_full_word - beg_full_word < 32) { |
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286 clear_range(beg, end); |
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287 return; |
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288 } |
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289 |
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290 // The range includes at least one full word. |
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291 clear_range_within_word(beg, bit_index(beg_full_word)); |
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292 clear_large_range_of_words(beg_full_word, end_full_word); |
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293 clear_range_within_word(bit_index(end_full_word), end); |
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294 } |
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295 |
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296 void BitMap::at_put(idx_t offset, bool value) { |
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297 if (value) { |
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298 set_bit(offset); |
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299 } else { |
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300 clear_bit(offset); |
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301 } |
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302 } |
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303 |
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304 // Return true to indicate that this thread changed |
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305 // the bit, false to indicate that someone else did. |
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306 // In either case, the requested bit is in the |
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307 // requested state some time during the period that |
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308 // this thread is executing this call. More importantly, |
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309 // if no other thread is executing an action to |
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310 // change the requested bit to a state other than |
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311 // the one that this thread is trying to set it to, |
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312 // then the the bit is in the expected state |
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313 // at exit from this method. However, rather than |
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314 // make such a strong assertion here, based on |
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315 // assuming such constrained use (which though true |
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316 // today, could change in the future to service some |
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317 // funky parallel algorithm), we encourage callers |
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318 // to do such verification, as and when appropriate. |
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319 bool BitMap::par_at_put(idx_t bit, bool value) { |
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320 return value ? par_set_bit(bit) : par_clear_bit(bit); |
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321 } |
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322 |
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323 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) { |
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324 if (value) { |
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325 set_range(start_offset, end_offset); |
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326 } else { |
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327 clear_range(start_offset, end_offset); |
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328 } |
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329 } |
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330 |
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331 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) { |
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332 verify_range(beg, end); |
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333 |
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334 idx_t beg_full_word = word_index_round_up(beg); |
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335 idx_t end_full_word = word_index(end); |
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336 |
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337 if (beg_full_word < end_full_word) { |
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338 // The range includes at least one full word. |
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339 par_put_range_within_word(beg, bit_index(beg_full_word), value); |
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340 if (value) { |
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341 set_range_of_words(beg_full_word, end_full_word); |
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342 } else { |
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343 clear_range_of_words(beg_full_word, end_full_word); |
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344 } |
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345 par_put_range_within_word(bit_index(end_full_word), end, value); |
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346 } else { |
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347 // The range spans at most 2 partial words. |
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348 idx_t boundary = MIN2(bit_index(beg_full_word), end); |
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349 par_put_range_within_word(beg, boundary, value); |
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350 par_put_range_within_word(boundary, end, value); |
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351 } |
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352 |
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353 } |
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354 |
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355 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) { |
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356 if (value) { |
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357 set_large_range(beg, end); |
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358 } else { |
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359 clear_large_range(beg, end); |
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360 } |
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361 } |
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362 |
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363 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) { |
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364 verify_range(beg, end); |
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365 |
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366 idx_t beg_full_word = word_index_round_up(beg); |
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367 idx_t end_full_word = word_index(end); |
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368 |
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369 assert(end_full_word - beg_full_word >= 32, |
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370 "the range must include at least 32 bytes"); |
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371 |
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372 // The range includes at least one full word. |
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373 par_put_range_within_word(beg, bit_index(beg_full_word), value); |
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374 if (value) { |
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375 set_large_range_of_words(beg_full_word, end_full_word); |
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376 } else { |
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377 clear_large_range_of_words(beg_full_word, end_full_word); |
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378 } |
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379 par_put_range_within_word(bit_index(end_full_word), end, value); |
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380 } |
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381 |
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382 inline bm_word_t tail_mask(idx_t tail_bits) { |
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383 assert(tail_bits != 0, "precondition"); // Works, but shouldn't be called. |
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384 assert(tail_bits < (idx_t)BitsPerWord, "precondition"); |
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385 return (bm_word_t(1) << tail_bits) - 1; |
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386 } |
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387 |
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388 // Get the low tail_bits of value, which is the last partial word of a map. |
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389 inline bm_word_t tail_of_map(bm_word_t value, idx_t tail_bits) { |
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390 return value & tail_mask(tail_bits); |
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391 } |
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392 |
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393 // Compute the new last word of a map with a non-aligned length. |
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394 // new_value has the new trailing bits of the map in the low tail_bits. |
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395 // old_value is the last word of the map, including bits beyond the end. |
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396 // Returns old_value with the low tail_bits replaced by the corresponding |
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397 // bits in new_value. |
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398 inline bm_word_t merge_tail_of_map(bm_word_t new_value, |
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399 bm_word_t old_value, |
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400 idx_t tail_bits) { |
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401 bm_word_t mask = tail_mask(tail_bits); |
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402 return (new_value & mask) | (old_value & ~mask); |
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403 } |
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404 |
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405 bool BitMap::contains(const BitMap& other) const { |
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406 assert(size() == other.size(), "must have same size"); |
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407 const bm_word_t* dest_map = map(); |
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408 const bm_word_t* other_map = other.map(); |
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409 idx_t limit = word_index(size()); |
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410 for (idx_t index = 0; index < limit; ++index) { |
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411 // false if other bitmap has bits set which are clear in this bitmap. |
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412 if ((~dest_map[index] & other_map[index]) != 0) return false; |
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413 } |
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414 idx_t rest = bit_in_word(size()); |
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415 // true unless there is a partial-word tail in which the other |
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416 // bitmap has bits set which are clear in this bitmap. |
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417 return (rest == 0) || tail_of_map(~dest_map[limit] & other_map[limit], rest) == 0; |
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418 } |
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419 |
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420 bool BitMap::intersects(const BitMap& other) const { |
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421 assert(size() == other.size(), "must have same size"); |
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422 const bm_word_t* dest_map = map(); |
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423 const bm_word_t* other_map = other.map(); |
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424 idx_t limit = word_index(size()); |
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425 for (idx_t index = 0; index < limit; ++index) { |
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426 if ((dest_map[index] & other_map[index]) != 0) return true; |
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427 } |
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428 idx_t rest = bit_in_word(size()); |
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429 // false unless there is a partial-word tail with non-empty intersection. |
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430 return (rest > 0) && tail_of_map(dest_map[limit] & other_map[limit], rest) != 0; |
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431 } |
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432 |
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433 void BitMap::set_union(const BitMap& other) { |
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434 assert(size() == other.size(), "must have same size"); |
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435 bm_word_t* dest_map = map(); |
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436 const bm_word_t* other_map = other.map(); |
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437 idx_t limit = word_index(size()); |
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438 for (idx_t index = 0; index < limit; ++index) { |
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439 dest_map[index] |= other_map[index]; |
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440 } |
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441 idx_t rest = bit_in_word(size()); |
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442 if (rest > 0) { |
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443 bm_word_t orig = dest_map[limit]; |
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444 dest_map[limit] = merge_tail_of_map(orig | other_map[limit], orig, rest); |
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445 } |
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446 } |
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447 |
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448 void BitMap::set_difference(const BitMap& other) { |
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449 assert(size() == other.size(), "must have same size"); |
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450 bm_word_t* dest_map = map(); |
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451 const bm_word_t* other_map = other.map(); |
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452 idx_t limit = word_index(size()); |
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453 for (idx_t index = 0; index < limit; ++index) { |
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454 dest_map[index] &= ~other_map[index]; |
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455 } |
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456 idx_t rest = bit_in_word(size()); |
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457 if (rest > 0) { |
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458 bm_word_t orig = dest_map[limit]; |
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459 dest_map[limit] = merge_tail_of_map(orig & ~other_map[limit], orig, rest); |
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460 } |
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461 } |
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462 |
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463 void BitMap::set_intersection(const BitMap& other) { |
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464 assert(size() == other.size(), "must have same size"); |
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465 bm_word_t* dest_map = map(); |
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466 const bm_word_t* other_map = other.map(); |
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467 idx_t limit = word_index(size()); |
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468 for (idx_t index = 0; index < limit; ++index) { |
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469 dest_map[index] &= other_map[index]; |
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470 } |
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471 idx_t rest = bit_in_word(size()); |
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472 if (rest > 0) { |
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473 bm_word_t orig = dest_map[limit]; |
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474 dest_map[limit] = merge_tail_of_map(orig & other_map[limit], orig, rest); |
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475 } |
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476 } |
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477 |
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478 bool BitMap::set_union_with_result(const BitMap& other) { |
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479 assert(size() == other.size(), "must have same size"); |
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480 bool changed = false; |
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481 bm_word_t* dest_map = map(); |
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482 const bm_word_t* other_map = other.map(); |
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483 idx_t limit = word_index(size()); |
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484 for (idx_t index = 0; index < limit; ++index) { |
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485 bm_word_t orig = dest_map[index]; |
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486 bm_word_t temp = orig | other_map[index]; |
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487 changed = changed || (temp != orig); |
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488 dest_map[index] = temp; |
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489 } |
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490 idx_t rest = bit_in_word(size()); |
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491 if (rest > 0) { |
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492 bm_word_t orig = dest_map[limit]; |
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493 bm_word_t temp = merge_tail_of_map(orig | other_map[limit], orig, rest); |
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494 changed = changed || (temp != orig); |
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495 dest_map[limit] = temp; |
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496 } |
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497 return changed; |
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498 } |
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499 |
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500 bool BitMap::set_difference_with_result(const BitMap& other) { |
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501 assert(size() == other.size(), "must have same size"); |
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502 bool changed = false; |
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503 bm_word_t* dest_map = map(); |
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504 const bm_word_t* other_map = other.map(); |
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505 idx_t limit = word_index(size()); |
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506 for (idx_t index = 0; index < limit; ++index) { |
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507 bm_word_t orig = dest_map[index]; |
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508 bm_word_t temp = orig & ~other_map[index]; |
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509 changed = changed || (temp != orig); |
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510 dest_map[index] = temp; |
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511 } |
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512 idx_t rest = bit_in_word(size()); |
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513 if (rest > 0) { |
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514 bm_word_t orig = dest_map[limit]; |
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515 bm_word_t temp = merge_tail_of_map(orig & ~other_map[limit], orig, rest); |
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516 changed = changed || (temp != orig); |
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517 dest_map[limit] = temp; |
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518 } |
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519 return changed; |
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520 } |
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521 |
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522 bool BitMap::set_intersection_with_result(const BitMap& other) { |
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523 assert(size() == other.size(), "must have same size"); |
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524 bool changed = false; |
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525 bm_word_t* dest_map = map(); |
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526 const bm_word_t* other_map = other.map(); |
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527 idx_t limit = word_index(size()); |
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528 for (idx_t index = 0; index < limit; ++index) { |
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529 bm_word_t orig = dest_map[index]; |
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530 bm_word_t temp = orig & other_map[index]; |
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531 changed = changed || (temp != orig); |
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532 dest_map[index] = temp; |
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533 } |
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534 idx_t rest = bit_in_word(size()); |
|
535 if (rest > 0) { |
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536 bm_word_t orig = dest_map[limit]; |
|
537 bm_word_t temp = merge_tail_of_map(orig & other_map[limit], orig, rest); |
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538 changed = changed || (temp != orig); |
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539 dest_map[limit] = temp; |
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540 } |
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541 return changed; |
|
542 } |
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543 |
|
544 void BitMap::set_from(const BitMap& other) { |
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545 assert(size() == other.size(), "must have same size"); |
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546 bm_word_t* dest_map = map(); |
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547 const bm_word_t* other_map = other.map(); |
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548 idx_t copy_words = word_index(size()); |
|
549 Copy::disjoint_words((HeapWord*)other_map, (HeapWord*)dest_map, copy_words); |
|
550 idx_t rest = bit_in_word(size()); |
|
551 if (rest > 0) { |
|
552 dest_map[copy_words] = merge_tail_of_map(other_map[copy_words], |
|
553 dest_map[copy_words], |
|
554 rest); |
|
555 } |
|
556 } |
|
557 |
|
558 bool BitMap::is_same(const BitMap& other) const { |
|
559 assert(size() == other.size(), "must have same size"); |
|
560 const bm_word_t* dest_map = map(); |
|
561 const bm_word_t* other_map = other.map(); |
|
562 idx_t limit = word_index(size()); |
|
563 for (idx_t index = 0; index < limit; ++index) { |
|
564 if (dest_map[index] != other_map[index]) return false; |
|
565 } |
|
566 idx_t rest = bit_in_word(size()); |
|
567 return (rest == 0) || (tail_of_map(dest_map[limit] ^ other_map[limit], rest) == 0); |
|
568 } |
|
569 |
|
570 bool BitMap::is_full() const { |
|
571 const bm_word_t* words = map(); |
|
572 idx_t limit = word_index(size()); |
|
573 for (idx_t index = 0; index < limit; ++index) { |
|
574 if (~words[index] != 0) return false; |
|
575 } |
|
576 idx_t rest = bit_in_word(size()); |
|
577 return (rest == 0) || (tail_of_map(~words[limit], rest) == 0); |
|
578 } |
|
579 |
|
580 bool BitMap::is_empty() const { |
|
581 const bm_word_t* words = map(); |
|
582 idx_t limit = word_index(size()); |
|
583 for (idx_t index = 0; index < limit; ++index) { |
|
584 if (words[index] != 0) return false; |
|
585 } |
|
586 idx_t rest = bit_in_word(size()); |
|
587 return (rest == 0) || (tail_of_map(words[limit], rest) == 0); |
|
588 } |
|
589 |
|
590 void BitMap::clear_large() { |
|
591 clear_large_range_of_words(0, size_in_words()); |
|
592 } |
|
593 |
|
594 // Note that if the closure itself modifies the bitmap |
|
595 // then modifications in and to the left of the _bit_ being |
|
596 // currently sampled will not be seen. Note also that the |
|
597 // interval [leftOffset, rightOffset) is right open. |
|
598 bool BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) { |
|
599 verify_range(leftOffset, rightOffset); |
|
600 |
|
601 idx_t startIndex = word_index(leftOffset); |
|
602 idx_t endIndex = MIN2(word_index(rightOffset) + 1, size_in_words()); |
|
603 for (idx_t index = startIndex, offset = leftOffset; |
|
604 offset < rightOffset && index < endIndex; |
|
605 offset = (++index) << LogBitsPerWord) { |
|
606 idx_t rest = map(index) >> (offset & (BitsPerWord - 1)); |
|
607 for (; offset < rightOffset && rest != 0; offset++) { |
|
608 if (rest & 1) { |
|
609 if (!blk->do_bit(offset)) return false; |
|
610 // resample at each closure application |
|
611 // (see, for instance, CMS bug 4525989) |
|
612 rest = map(index) >> (offset & (BitsPerWord -1)); |
|
613 } |
|
614 rest = rest >> 1; |
|
615 } |
|
616 } |
|
617 return true; |
|
618 } |
|
619 |
|
620 const BitMap::idx_t* BitMap::_pop_count_table = NULL; |
|
621 |
|
622 void BitMap::init_pop_count_table() { |
|
623 if (_pop_count_table == NULL) { |
|
624 BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256, mtInternal); |
|
625 for (uint i = 0; i < 256; i++) { |
|
626 table[i] = num_set_bits(i); |
|
627 } |
|
628 |
|
629 if (!Atomic::replace_if_null(table, &_pop_count_table)) { |
|
630 guarantee(_pop_count_table != NULL, "invariant"); |
|
631 FREE_C_HEAP_ARRAY(idx_t, table); |
|
632 } |
|
633 } |
|
634 } |
|
635 |
|
636 BitMap::idx_t BitMap::num_set_bits(bm_word_t w) { |
|
637 idx_t bits = 0; |
|
638 |
|
639 while (w != 0) { |
|
640 while ((w & 1) == 0) { |
|
641 w >>= 1; |
|
642 } |
|
643 bits++; |
|
644 w >>= 1; |
|
645 } |
|
646 return bits; |
|
647 } |
|
648 |
|
649 BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) { |
|
650 assert(_pop_count_table != NULL, "precondition"); |
|
651 return _pop_count_table[c]; |
|
652 } |
|
653 |
|
654 BitMap::idx_t BitMap::count_one_bits() const { |
|
655 init_pop_count_table(); // If necessary. |
|
656 idx_t sum = 0; |
|
657 typedef unsigned char uchar; |
|
658 for (idx_t i = 0; i < size_in_words(); i++) { |
|
659 bm_word_t w = map()[i]; |
|
660 for (size_t j = 0; j < sizeof(bm_word_t); j++) { |
|
661 sum += num_set_bits_from_table(uchar(w & 255)); |
|
662 w >>= 8; |
|
663 } |
|
664 } |
|
665 return sum; |
|
666 } |
|
667 |
|
668 void BitMap::print_on_error(outputStream* st, const char* prefix) const { |
|
669 st->print_cr("%s[" PTR_FORMAT ", " PTR_FORMAT ")", |
|
670 prefix, p2i(map()), p2i((char*)map() + (size() >> LogBitsPerByte))); |
|
671 } |
|
672 |
|
673 #ifndef PRODUCT |
|
674 |
|
675 void BitMap::print_on(outputStream* st) const { |
|
676 tty->print("Bitmap(" SIZE_FORMAT "):", size()); |
|
677 for (idx_t index = 0; index < size(); index++) { |
|
678 tty->print("%c", at(index) ? '1' : '0'); |
|
679 } |
|
680 tty->cr(); |
|
681 } |
|
682 |
|
683 #endif |