1 | /*
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2 | * Souffle - A Datalog Compiler
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3 | * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved
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4 | * Licensed under the Universal Permissive License v 1.0 as shown at:
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5 | * - https://opensource.org/licenses/UPL
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6 | * - <souffle root>/licenses/SOUFFLE-UPL.txt
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7 | */
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8 |
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9 | /************************************************************************
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10 | *
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11 | * @file BTree.h
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12 | *
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13 | * An implementation of a generic B-tree data structure including
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14 | * interfaces for utilizing instances as set or multiset containers.
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15 | *
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16 | ***********************************************************************/
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17 |
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18 | #pragma once
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19 |
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20 | #include "souffle/datastructure/BTreeUtil.h"
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21 | #include "souffle/utility/CacheUtil.h"
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22 | #include "souffle/utility/ContainerUtil.h"
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23 | #include "souffle/utility/MiscUtil.h"
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24 | #include "souffle/utility/ParallelUtil.h"
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25 | #include <algorithm>
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26 | #include <cassert>
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27 | #include <cstddef>
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28 | #include <cstdint>
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29 | #include <iostream>
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30 | #include <iterator>
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31 | #include <string>
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32 | #include <tuple>
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33 | #include <type_traits>
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34 | #include <typeinfo>
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35 | #include <vector>
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36 |
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37 | namespace souffle {
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38 |
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39 | namespace detail {
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40 |
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41 | /**
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42 | * The actual implementation of a b-tree data structure.
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43 | *
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44 | * @tparam Key .. the element type to be stored in this tree
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45 | * @tparam Comparator .. a class defining an order on the stored elements
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46 | * @tparam Allocator .. utilized for allocating memory for required nodes
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47 | * @tparam blockSize .. determines the number of bytes/block utilized by leaf nodes
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48 | * @tparam SearchStrategy .. enables switching between linear, binary or any other search strategy
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49 | * @tparam isSet .. true = set, false = multiset
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50 | */
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51 | template <typename Key, typename Comparator,
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52 | typename Allocator, // is ignored so far - TODO: add support
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53 | unsigned blockSize, typename SearchStrategy, bool isSet, typename WeakComparator = Comparator,
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54 | typename Updater = detail::updater<Key>>
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55 | class btree {
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56 | public:
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57 | class iterator;
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58 | using const_iterator = iterator;
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59 |
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60 | using key_type = Key;
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61 | using element_type = Key;
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62 | using chunk = range<iterator>;
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63 |
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64 | protected:
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65 | /* ------------- static utilities ----------------- */
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66 |
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67 | const static SearchStrategy search;
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68 |
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69 | /* ---------- comparison utilities ---------------- */
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70 |
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71 | mutable Comparator comp;
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72 |
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73 | bool less(const Key& a, const Key& b) const {
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74 | return comp.less(a, b);
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75 | }
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76 |
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77 | bool equal(const Key& a, const Key& b) const {
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78 | return comp.equal(a, b);
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79 | }
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80 |
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81 | mutable WeakComparator weak_comp;
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82 |
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83 | bool weak_less(const Key& a, const Key& b) const {
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84 | return weak_comp.less(a, b);
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85 | }
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86 |
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87 | bool weak_equal(const Key& a, const Key& b) const {
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88 | return weak_comp.equal(a, b);
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89 | }
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90 |
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91 | /* -------------- updater utilities ------------- */
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92 |
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93 | mutable Updater upd;
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94 | bool update(Key& old_k, const Key& new_k) {
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95 | return upd.update(old_k, new_k);
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96 | }
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97 |
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98 | /* -------------- the node type ----------------- */
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99 |
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100 | using size_type = std::size_t;
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101 | using field_index_type = uint8_t;
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102 | using lock_type = OptimisticReadWriteLock;
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103 |
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104 | struct node;
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105 |
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106 | /**
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107 | * The base type of all node types containing essential
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108 | * book-keeping information.
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109 | */
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110 | struct base {
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111 | #ifdef IS_PARALLEL
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112 |
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113 | // the parent node
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114 | node* volatile parent;
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115 |
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116 | // a lock for synchronizing parallel operations on this node
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117 | lock_type lock;
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118 |
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119 | // the number of keys in this node
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120 | volatile size_type numElements;
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121 |
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122 | // the position in the parent node
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123 | volatile field_index_type position;
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124 | #else
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125 | // the parent node
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126 | node* parent;
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127 |
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128 | // the number of keys in this node
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129 | size_type numElements;
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130 |
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131 | // the position in the parent node
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132 | field_index_type position;
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133 | #endif
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134 |
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135 | // a flag indicating whether this is a inner node or not
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136 | const bool inner;
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137 |
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138 | /**
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139 | * A simple constructor for nodes
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140 | */
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141 | base(bool inner) : parent(nullptr), numElements(0), position(0), inner(inner) {}
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142 |
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143 | bool isLeaf() const {
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144 | return !inner;
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145 | }
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146 |
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147 | bool isInner() const {
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148 | return inner;
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149 | }
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150 |
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151 | node* getParent() const {
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152 | return parent;
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153 | }
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154 |
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155 | field_index_type getPositionInParent() const {
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156 | return position;
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157 | }
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158 |
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159 | size_type getNumElements() const {
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160 | return numElements;
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161 | }
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162 | };
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163 |
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164 | struct inner_node;
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165 |
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166 | /**
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167 | * The actual, generic node implementation covering the operations
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168 | * for both, inner and leaf nodes.
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169 | */
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170 | struct node : public base {
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171 | /**
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172 | * The number of keys/node desired by the user.
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173 | */
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174 | static constexpr std::size_t desiredNumKeys =
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175 | ((blockSize > sizeof(base)) ? blockSize - sizeof(base) : 0) / sizeof(Key);
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176 |
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177 | /**
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178 | * The actual number of keys/node corrected by functional requirements.
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179 | */
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180 | static constexpr std::size_t maxKeys = (desiredNumKeys > 3) ? desiredNumKeys : 3;
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181 |
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182 | // the keys stored in this node
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183 | Key keys[maxKeys];
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184 |
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185 | // a simple constructor
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186 | node(bool inner) : base(inner) {}
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187 |
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188 | /**
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189 | * A deep-copy operation creating a clone of this node.
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190 | */
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191 | node* clone() const {
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192 | // create a clone of this node
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193 | node* res = (this->isInner()) ? static_cast<node*>(new inner_node())
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194 | : static_cast<node*>(new leaf_node());
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195 |
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196 | // copy basic fields
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197 | res->position = this->position;
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198 | res->numElements = this->numElements;
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199 |
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200 | for (size_type i = 0; i < this->numElements; ++i) {
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201 | res->keys[i] = this->keys[i];
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202 | }
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203 |
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204 | // if this is a leaf we are done
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205 | if (this->isLeaf()) {
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206 | return res;
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207 | }
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208 |
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209 | // copy child nodes recursively
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210 | auto* ires = (inner_node*)res;
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211 | for (size_type i = 0; i <= this->numElements; ++i) {
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212 | ires->children[i] = this->getChild(i)->clone();
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213 | ires->children[i]->parent = res;
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214 | }
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215 |
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216 | // that's it
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217 | return res;
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218 | }
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219 |
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220 | /**
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221 | * A utility function providing a reference to this node as
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222 | * an inner node.
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223 | */
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224 | inner_node& asInnerNode() {
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225 | assert(this->inner && "Invalid cast!");
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226 | return *static_cast<inner_node*>(this);
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227 | }
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228 |
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229 | /**
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230 | * A utility function providing a reference to this node as
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231 | * a const inner node.
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232 | */
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233 | const inner_node& asInnerNode() const {
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234 | assert(this->inner && "Invalid cast!");
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235 | return *static_cast<const inner_node*>(this);
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236 | }
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237 |
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238 | /**
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239 | * Computes the number of nested levels of the tree rooted
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240 | * by this node.
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241 | */
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242 | size_type getDepth() const {
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243 | if (this->isLeaf()) {
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244 | return 1;
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245 | }
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246 | return getChild(0)->getDepth() + 1;
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247 | }
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248 |
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249 | /**
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250 | * Counts the number of nodes contained in the sub-tree rooted
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251 | * by this node.
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252 | */
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253 | size_type countNodes() const {
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254 | if (this->isLeaf()) {
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255 | return 1;
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256 | }
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257 | size_type sum = 1;
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258 | for (unsigned i = 0; i <= this->numElements; ++i) {
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259 | sum += getChild(i)->countNodes();
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260 | }
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261 | return sum;
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262 | }
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263 |
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264 | /**
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265 | * Counts the number of entries contained in the sub-tree rooted
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266 | * by this node.
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267 | */
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268 | size_type countEntries() const {
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269 | if (this->isLeaf()) {
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270 | return this->numElements;
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271 | }
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272 | size_type sum = this->numElements;
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273 | for (unsigned i = 0; i <= this->numElements; ++i) {
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274 | sum += getChild(i)->countEntries();
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275 | }
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276 | return sum;
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277 | }
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278 |
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279 | /**
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280 | * Determines the amount of memory used by the sub-tree rooted
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281 | * by this node.
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282 | */
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283 | size_type getMemoryUsage() const {
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284 | if (this->isLeaf()) {
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285 | return sizeof(leaf_node);
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286 | }
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287 | size_type res = sizeof(inner_node);
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288 | for (unsigned i = 0; i <= this->numElements; ++i) {
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289 | res += getChild(i)->getMemoryUsage();
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290 | }
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291 | return res;
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292 | }
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293 |
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294 | /**
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295 | * Obtains a pointer to the array of child-pointers
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296 | * of this node -- if it is an inner node.
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297 | */
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298 | node** getChildren() {
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299 | return asInnerNode().children;
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300 | }
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301 |
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302 | /**
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303 | * Obtains a pointer to the array of const child-pointers
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304 | * of this node -- if it is an inner node.
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305 | */
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306 | node* const* getChildren() const {
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307 | return asInnerNode().children;
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308 | }
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309 |
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310 | /**
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311 | * Obtains a reference to the child of the given index.
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312 | */
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313 | node* getChild(size_type s) const {
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314 | return asInnerNode().children[s];
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315 | }
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316 |
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317 | /**
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318 | * Checks whether this node is empty -- can happen due to biased insertion.
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319 | */
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320 | bool isEmpty() const {
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321 | return this->numElements == 0;
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322 | }
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323 |
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324 | /**
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325 | * Checks whether this node is full.
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326 | */
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327 | bool isFull() const {
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328 | return this->numElements == maxKeys;
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329 | }
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330 |
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331 | /**
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332 | * Obtains the point at which full nodes should be split.
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333 | * Conventional b-trees always split in half. However, in cases
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334 | * where in-order insertions are frequent, a split assigning
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335 | * larger portions to the right fragment provide higher performance
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336 | * and a better node-filling rate.
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337 | */
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338 | int getSplitPoint(int /*unused*/) {
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339 | return static_cast<int>(std::min(3 * maxKeys / 4, maxKeys - 2));
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340 | }
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341 |
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342 | /**
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343 | * Splits this node.
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344 | *
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345 | * @param root .. a pointer to the root-pointer of the enclosing b-tree
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346 | * (might have to be updated if the root-node needs to be split)
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347 | * @param idx .. the position of the insert causing the split
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348 | */
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349 | #ifdef IS_PARALLEL
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350 | void split(node** root, lock_type& root_lock, int idx, std::vector<node*>& locked_nodes) {
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351 | assert(this->lock.is_write_locked());
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352 | assert(!this->parent || this->parent->lock.is_write_locked());
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353 | assert((this->parent != nullptr) || root_lock.is_write_locked());
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354 | assert(this->isLeaf() || souffle::contains(locked_nodes, this));
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355 | assert(!this->parent || souffle::contains(locked_nodes, const_cast<node*>(this->parent)));
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356 | #else
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357 | void split(node** root, lock_type& root_lock, int idx) {
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358 | #endif
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359 | assert(this->numElements == maxKeys);
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360 |
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361 | // get middle element
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362 | int split_point = getSplitPoint(idx);
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363 |
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364 | // create a new sibling node
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365 | node* sibling = (this->inner) ? static_cast<node*>(new inner_node())
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366 | : static_cast<node*>(new leaf_node());
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367 |
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368 | #ifdef IS_PARALLEL
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369 | // lock sibling
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370 | sibling->lock.start_write();
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371 | locked_nodes.push_back(sibling);
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372 | #endif
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373 |
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374 | // move data over to the new node
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375 | for (unsigned i = split_point + 1, j = 0; i < maxKeys; ++i, ++j) {
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376 | sibling->keys[j] = keys[i];
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377 | }
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378 |
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379 | // move child pointers
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380 | if (this->inner) {
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381 | // move pointers to sibling
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382 | auto* other = static_cast<inner_node*>(sibling);
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383 | for (unsigned i = split_point + 1, j = 0; i <= maxKeys; ++i, ++j) {
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384 | other->children[j] = getChildren()[i];
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385 | other->children[j]->parent = other;
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386 | other->children[j]->position = static_cast<field_index_type>(j);
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387 | }
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388 | }
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389 |
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390 | // update number of elements
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391 | this->numElements = split_point;
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392 | sibling->numElements = maxKeys - split_point - 1;
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393 |
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394 | // update parent
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395 | #ifdef IS_PARALLEL
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396 | grow_parent(root, root_lock, sibling, locked_nodes);
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397 | #else
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398 | grow_parent(root, root_lock, sibling);
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399 | #endif
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400 | }
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401 |
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402 | /**
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403 | * Moves keys from this node to one of its siblings or splits
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404 | * this node to make some space for the insertion of an element at
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405 | * position idx.
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406 | *
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407 | * Returns the number of elements moved to the left side, 0 in case
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408 | * of a split. The number of moved elements will be <= the given idx.
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409 | *
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410 | * @param root .. the root node of the b-tree being part of
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411 | * @param idx .. the position of the insert triggering this operation
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412 | */
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413 | // TODO: remove root_lock ... no longer needed
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414 | #ifdef IS_PARALLEL
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415 | int rebalance_or_split(node** root, lock_type& root_lock, int idx, std::vector<node*>& locked_nodes) {
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416 | assert(this->lock.is_write_locked());
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417 | assert(!this->parent || this->parent->lock.is_write_locked());
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418 | assert((this->parent != nullptr) || root_lock.is_write_locked());
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419 | assert(this->isLeaf() || souffle::contains(locked_nodes, this));
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420 | assert(!this->parent || souffle::contains(locked_nodes, const_cast<node*>(this->parent)));
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421 | #else
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422 | int rebalance_or_split(node** root, lock_type& root_lock, int idx) {
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423 | #endif
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424 |
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425 | // this node is full ... and needs some space
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426 | assert(this->numElements == maxKeys);
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427 |
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428 | // get snap-shot of parent
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429 | auto parent = this->parent;
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430 | auto pos = this->position;
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431 |
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432 | // Option A) re-balance data
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433 | if (parent && pos > 0) {
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434 | node* left = parent->getChild(pos - 1);
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435 |
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436 | #ifdef IS_PARALLEL
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437 | // lock access to left sibling
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438 | if (!left->lock.try_start_write()) {
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439 | // left node is currently updated => skip balancing and split
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440 | split(root, root_lock, idx, locked_nodes);
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441 | return 0;
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442 | }
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443 | #endif
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444 |
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445 | // compute number of elements to be movable to left
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446 | // space available in left vs. insertion index
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447 | size_type num = static_cast<size_type>(
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448 | std::min<int>(static_cast<int>(maxKeys - left->numElements), idx));
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449 |
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450 | // if there are elements to move ..
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451 | if (num > 0) {
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452 | Key* splitter = &(parent->keys[this->position - 1]);
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453 |
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454 | // .. move keys to left node
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455 | left->keys[left->numElements] = *splitter;
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456 | for (size_type i = 0; i < num - 1; ++i) {
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457 | left->keys[left->numElements + 1 + i] = keys[i];
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458 | }
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459 | *splitter = keys[num - 1];
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460 |
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461 | // shift keys in this node to the left
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462 | for (size_type i = 0; i < this->numElements - num; ++i) {
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463 | keys[i] = keys[i + num];
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464 | }
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465 |
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466 | // .. and children if necessary
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467 | if (this->isInner()) {
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468 | auto* ileft = static_cast<inner_node*>(left);
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469 | auto* iright = static_cast<inner_node*>(this);
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470 |
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471 | // move children
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472 | for (field_index_type i = 0; i < num; ++i) {
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473 | ileft->children[left->numElements + i + 1] = iright->children[i];
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474 | }
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475 |
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476 | // update moved children
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477 | for (size_type i = 0; i < num; ++i) {
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478 | iright->children[i]->parent = ileft;
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479 | iright->children[i]->position =
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480 | static_cast<field_index_type>(left->numElements + i) + 1;
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481 | }
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482 |
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483 | // shift child-pointer to the left
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484 | for (size_type i = 0; i < this->numElements - num + 1; ++i) {
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485 | iright->children[i] = iright->children[i + num];
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486 | }
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487 |
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488 | // update position of children
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489 | for (size_type i = 0; i < this->numElements - num + 1; ++i) {
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490 | iright->children[i]->position = static_cast<field_index_type>(i);
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491 | }
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492 | }
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493 |
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494 | // update node sizes
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495 | left->numElements += num;
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496 | this->numElements -= num;
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497 |
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498 | #ifdef IS_PARALLEL
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499 | left->lock.end_write();
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500 | #endif
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501 |
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502 | // done
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503 | return static_cast<int>(num);
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504 | }
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505 |
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506 | #ifdef IS_PARALLEL
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507 | left->lock.abort_write();
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508 | #endif
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509 | }
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510 |
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511 | // Option B) split node
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512 | #ifdef IS_PARALLEL
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513 | split(root, root_lock, idx, locked_nodes);
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514 | #else
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515 | split(root, root_lock, idx);
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516 | #endif
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517 | return 0; // = no re-balancing
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518 | }
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519 |
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520 | private:
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521 | /**
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522 | * Inserts a new sibling into the parent of this node utilizing
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523 | * the last key of this node as a separation key. (for internal
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524 | * use only)
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525 | *
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526 | * @param root .. a pointer to the root-pointer of the containing tree
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527 | * @param sibling .. the new right-sibling to be add to the parent node
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528 | */
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529 | #ifdef IS_PARALLEL
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530 | void grow_parent(node** root, lock_type& root_lock, node* sibling, std::vector<node*>& locked_nodes) {
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531 | assert(this->lock.is_write_locked());
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532 | assert(!this->parent || this->parent->lock.is_write_locked());
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533 | assert((this->parent != nullptr) || root_lock.is_write_locked());
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534 | assert(this->isLeaf() || souffle::contains(locked_nodes, this));
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535 | assert(!this->parent || souffle::contains(locked_nodes, const_cast<node*>(this->parent)));
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536 | #else
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537 | void grow_parent(node** root, lock_type& root_lock, node* sibling) {
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538 | #endif
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539 |
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540 | if (this->parent == nullptr) {
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541 | assert(*root == this);
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542 |
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543 | // create a new root node
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544 | auto* new_root = new inner_node();
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545 | new_root->numElements = 1;
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546 | new_root->keys[0] = keys[this->numElements];
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547 |
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548 | new_root->children[0] = this;
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549 | new_root->children[1] = sibling;
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550 |
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551 | // link this and the sibling node to new root
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552 | this->parent = new_root;
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553 | sibling->parent = new_root;
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554 | sibling->position = 1;
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555 |
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556 | // switch root node
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557 | *root = new_root;
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558 |
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559 | } else {
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560 | // insert new element in parent element
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561 | auto parent = this->parent;
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562 | auto pos = this->position;
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563 |
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564 | #ifdef IS_PARALLEL
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565 | parent->insert_inner(
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566 | root, root_lock, pos, this, keys[this->numElements], sibling, locked_nodes);
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567 | #else
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568 | parent->insert_inner(root, root_lock, pos, this, keys[this->numElements], sibling);
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569 | #endif
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570 | }
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571 | }
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572 |
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573 | /**
|
574 | * Inserts a new element into an inner node (for internal use only).
|
575 | *
|
576 | * @param root .. a pointer to the root-pointer of the containing tree
|
577 | * @param pos .. the position to insert the new key
|
578 | * @param key .. the key to insert
|
579 | * @param newNode .. the new right-child of the inserted key
|
580 | */
|
581 | #ifdef IS_PARALLEL
|
582 | void insert_inner(node** root, lock_type& root_lock, unsigned pos, node* predecessor, const Key& key,
|
583 | node* newNode, std::vector<node*>& locked_nodes) {
|
584 | assert(this->lock.is_write_locked());
|
585 | assert(souffle::contains(locked_nodes, this));
|
586 | #else
|
587 | void insert_inner(node** root, lock_type& root_lock, unsigned pos, node* predecessor, const Key& key,
|
588 | node* newNode) {
|
589 | #endif
|
590 |
|
591 | // check capacity
|
592 | if (this->numElements >= maxKeys) {
|
593 | #ifdef IS_PARALLEL
|
594 | assert(!this->parent || this->parent->lock.is_write_locked());
|
595 | assert((this->parent) || root_lock.is_write_locked());
|
596 | assert(!this->parent || souffle::contains(locked_nodes, const_cast<node*>(this->parent)));
|
597 | #endif
|
598 |
|
599 | // split this node
|
600 | #ifdef IS_PARALLEL
|
601 | pos -= rebalance_or_split(root, root_lock, pos, locked_nodes);
|
602 | #else
|
603 | pos -= rebalance_or_split(root, root_lock, pos);
|
604 | #endif
|
605 |
|
606 | // complete insertion within new sibling if necessary
|
607 | if (pos > this->numElements) {
|
608 | // correct position
|
609 | pos = pos - static_cast<unsigned int>(this->numElements) - 1;
|
610 |
|
611 | // get new sibling
|
612 | auto other = this->parent->getChild(this->position + 1);
|
613 |
|
614 | #ifdef IS_PARALLEL
|
615 | // make sure other side is write locked
|
616 | assert(other->lock.is_write_locked());
|
617 | assert(souffle::contains(locked_nodes, other));
|
618 |
|
619 | // search for new position (since other may have been altered in the meanwhile)
|
620 | size_type i = 0;
|
621 | for (; i <= other->numElements; ++i) {
|
622 | if (other->getChild(i) == predecessor) {
|
623 | break;
|
624 | }
|
625 | }
|
626 |
|
627 | pos = (i > static_cast<unsigned>(other->numElements)) ? 0 : static_cast<unsigned>(i);
|
628 | other->insert_inner(root, root_lock, pos, predecessor, key, newNode, locked_nodes);
|
629 | #else
|
630 | other->insert_inner(root, root_lock, pos, predecessor, key, newNode);
|
631 | #endif
|
632 | return;
|
633 | }
|
634 | }
|
635 |
|
636 | // move bigger keys one forward
|
637 | for (int i = static_cast<int>(this->numElements) - 1; i >= (int)pos; --i) {
|
638 | keys[i + 1] = keys[i];
|
639 | getChildren()[i + 2] = getChildren()[i + 1];
|
640 | ++getChildren()[i + 2]->position;
|
641 | }
|
642 |
|
643 | // ensure proper position
|
644 | assert(getChild(pos) == predecessor);
|
645 |
|
646 | // insert new element
|
647 | keys[pos] = key;
|
648 | getChildren()[pos + 1] = newNode;
|
649 | newNode->parent = this;
|
650 | newNode->position = static_cast<field_index_type>(pos) + 1;
|
651 | ++this->numElements;
|
652 | }
|
653 |
|
654 | public:
|
655 | /**
|
656 | * Prints a textual representation of this tree to the given output stream.
|
657 | * This feature is mainly intended for debugging and tuning purposes.
|
658 | *
|
659 | * @see btree::printTree
|
660 | */
|
661 | void printTree(std::ostream& out, const std::string& prefix) const {
|
662 | // print the header
|
663 | out << prefix << "@" << this << "[" << ((int)(this->position)) << "] - "
|
664 | << (this->inner ? "i" : "") << "node : " << this->numElements << "/" << maxKeys << " [";
|
665 |
|
666 | // print the keys
|
667 | for (unsigned i = 0; i < this->numElements; i++) {
|
668 | out << keys[i];
|
669 | if (i != this->numElements - 1) {
|
670 | out << ",";
|
671 | }
|
672 | }
|
673 | out << "]";
|
674 |
|
675 | // print references to children
|
676 | if (this->inner) {
|
677 | out << " - [";
|
678 | for (unsigned i = 0; i <= this->numElements; i++) {
|
679 | out << getChildren()[i];
|
680 | if (i != this->numElements) {
|
681 | out << ",";
|
682 | }
|
683 | }
|
684 | out << "]";
|
685 | }
|
686 |
|
687 | #ifdef IS_PARALLEL
|
688 | // print the lock state
|
689 | if (this->lock.is_write_locked()) {
|
690 | std::cout << " locked";
|
691 | }
|
692 | #endif
|
693 |
|
694 | out << "\n";
|
695 |
|
696 | // print the children recursively
|
697 | if (this->inner) {
|
698 | for (unsigned i = 0; i < this->numElements + 1; ++i) {
|
699 | static_cast<const inner_node*>(this)->children[i]->printTree(out, prefix + " ");
|
700 | }
|
701 | }
|
702 | }
|
703 |
|
704 | /**
|
705 | * A function decomposing the sub-tree rooted by this node into approximately equally
|
706 | * sized chunks. To minimize computational overhead, no strict load balance nor limit
|
707 | * on the number of actual chunks is given.
|
708 | *
|
709 | * @see btree::getChunks()
|
710 | *
|
711 | * @param res .. the list of chunks to be extended
|
712 | * @param num .. the number of chunks to be produced
|
713 | * @param begin .. the iterator to start the first chunk with
|
714 | * @param end .. the iterator to end the last chunk with
|
715 | * @return the handed in list of chunks extended by generated chunks
|
716 | */
|
717 | std::vector<chunk>& collectChunks(
|
718 | std::vector<chunk>& res, size_type num, const iterator& begin, const iterator& end) const {
|
719 | assert(num > 0);
|
720 |
|
721 | // special case: this node is empty
|
722 | if (isEmpty()) {
|
723 | if (begin != end) {
|
724 | res.push_back(chunk(begin, end));
|
725 | }
|
726 | return res;
|
727 | }
|
728 |
|
729 | // special case: a single chunk is requested
|
730 | if (num == 1) {
|
731 | res.push_back(chunk(begin, end));
|
732 | return res;
|
733 | }
|
734 |
|
735 | // cut-off
|
736 | if (this->isLeaf() || num < (this->numElements + 1)) {
|
737 | auto step = this->numElements / num;
|
738 | if (step == 0) {
|
739 | step = 1;
|
740 | }
|
741 |
|
742 | size_type i = 0;
|
743 |
|
744 | // the first chunk starts at the begin
|
745 | res.push_back(chunk(begin, iterator(this, static_cast<field_index_type>(step) - 1)));
|
746 |
|
747 | // split up the main part
|
748 | for (i = step - 1; i < this->numElements - step; i += step) {
|
749 | res.push_back(chunk(iterator(this, static_cast<field_index_type>(i)),
|
750 | iterator(this, static_cast<field_index_type>(i + step))));
|
751 | }
|
752 |
|
753 | // the last chunk runs to the end
|
754 | res.push_back(chunk(iterator(this, static_cast<field_index_type>(i)), end));
|
755 |
|
756 | // done
|
757 | return res;
|
758 | }
|
759 |
|
760 | // else: collect chunks of sub-set elements
|
761 |
|
762 | auto part = num / (this->numElements + 1);
|
763 | assert(part > 0);
|
764 | getChild(0)->collectChunks(res, part, begin, iterator(this, 0));
|
765 | for (size_type i = 1; i < this->numElements; i++) {
|
766 | getChild(i)->collectChunks(res, part, iterator(this, static_cast<field_index_type>(i - 1)),
|
767 | iterator(this, static_cast<field_index_type>(i)));
|
768 | }
|
769 | getChild(this->numElements)
|
770 | ->collectChunks(res, num - (part * this->numElements),
|
771 | iterator(this, static_cast<field_index_type>(this->numElements) - 1), end);
|
772 |
|
773 | // done
|
774 | return res;
|
775 | }
|
776 |
|
777 | /**
|
778 | * A function to verify the consistency of this node.
|
779 | *
|
780 | * @param root ... a reference to the root of the enclosing tree.
|
781 | * @return true if valid, false otherwise
|
782 | */
|
783 | template <typename Comp>
|
784 | bool check(Comp& comp, const node* root) const {
|
785 | bool valid = true;
|
786 |
|
787 | // check fill-state
|
788 | if (this->numElements > maxKeys) {
|
789 | std::cout << "Node with " << this->numElements << "/" << maxKeys << " encountered!\n";
|
790 | valid = false;
|
791 | }
|
792 |
|
793 | // check root state
|
794 | if (root == this) {
|
795 | if (this->parent != nullptr) {
|
796 | std::cout << "Root not properly linked!\n";
|
797 | valid = false;
|
798 | }
|
799 | } else {
|
800 | // check parent relation
|
801 | if (!this->parent) {
|
802 | std::cout << "Invalid null-parent!\n";
|
803 | valid = false;
|
804 | } else {
|
805 | if (this->parent->getChildren()[this->position] != this) {
|
806 | std::cout << "Parent reference invalid!\n";
|
807 | std::cout << " Node: " << this << "\n";
|
808 | std::cout << " Parent: " << this->parent << "\n";
|
809 | std::cout << " Position: " << ((int)this->position) << "\n";
|
810 | valid = false;
|
811 | }
|
812 |
|
813 | // check parent key
|
814 | if (valid && this->position != 0 &&
|
815 | !(comp(this->parent->keys[this->position - 1], keys[0]) < ((isSet) ? 0 : 1))) {
|
816 | std::cout << "Left parent key not lower bound!\n";
|
817 | std::cout << " Node: " << this << "\n";
|
818 | std::cout << " Parent: " << this->parent << "\n";
|
819 | std::cout << " Position: " << ((int)this->position) << "\n";
|
820 | std::cout << " Key: " << (this->parent->keys[this->position]) << "\n";
|
821 | std::cout << " Lower: " << (keys[0]) << "\n";
|
822 | valid = false;
|
823 | }
|
824 |
|
825 | // check parent key
|
826 | if (valid && this->position != this->parent->numElements &&
|
827 | !(comp(keys[this->numElements - 1], this->parent->keys[this->position]) <
|
828 | ((isSet) ? 0 : 1))) {
|
829 | std::cout << "Right parent key not lower bound!\n";
|
830 | std::cout << " Node: " << this << "\n";
|
831 | std::cout << " Parent: " << this->parent << "\n";
|
832 | std::cout << " Position: " << ((int)this->position) << "\n";
|
833 | std::cout << " Key: " << (this->parent->keys[this->position]) << "\n";
|
834 | std::cout << " Upper: " << (keys[0]) << "\n";
|
835 | valid = false;
|
836 | }
|
837 | }
|
838 | }
|
839 |
|
840 | // check element order
|
841 | if (this->numElements > 0) {
|
842 | for (unsigned i = 0; i < this->numElements - 1; i++) {
|
843 | if (valid && !(comp(keys[i], keys[i + 1]) < ((isSet) ? 0 : 1))) {
|
844 | std::cout << "Element order invalid!\n";
|
845 | std::cout << " @" << this << " key " << i << " is " << keys[i] << " vs "
|
846 | << keys[i + 1] << "\n";
|
847 | valid = false;
|
848 | }
|
849 | }
|
850 | }
|
851 |
|
852 | // check state of sub-nodes
|
853 | if (this->inner) {
|
854 | for (unsigned i = 0; i <= this->numElements; i++) {
|
855 | valid &= getChildren()[i]->check(comp, root);
|
856 | }
|
857 | }
|
858 |
|
859 | return valid;
|
860 | }
|
861 | }; // namespace detail
|
862 |
|
863 | /**
|
864 | * The data type representing inner nodes of the b-tree. It extends
|
865 | * the generic implementation of a node by the storage locations
|
866 | * of child pointers.
|
867 | */
|
868 | struct inner_node : public node {
|
869 | // references to child nodes owned by this node
|
870 | node* children[node::maxKeys + 1];
|
871 |
|
872 | // a simple default constructor initializing member fields
|
873 | inner_node() : node(true) {}
|
874 |
|
875 | // clear up child nodes recursively
|
876 | ~inner_node() {
|
877 | for (unsigned i = 0; i <= this->numElements; ++i) {
|
878 | if (children[i] != nullptr) {
|
879 | if (children[i]->isLeaf()) {
|
880 | delete static_cast<leaf_node*>(children[i]);
|
881 | } else {
|
882 | delete static_cast<inner_node*>(children[i]);
|
883 | }
|
884 | }
|
885 | }
|
886 | }
|
887 | };
|
888 |
|
889 | /**
|
890 | * The data type representing leaf nodes of the b-tree. It does not
|
891 | * add any capabilities to the generic node type.
|
892 | */
|
893 | struct leaf_node : public node {
|
894 | // a simple default constructor initializing member fields
|
895 | leaf_node() : node(false) {}
|
896 | };
|
897 |
|
898 | // ------------------- iterators ------------------------
|
899 |
|
900 | public:
|
901 | /**
|
902 | * The iterator type to be utilized for scanning through btree instances.
|
903 | */
|
904 | class iterator {
|
905 | // a pointer to the node currently referred to
|
906 | node const* cur;
|
907 |
|
908 | // the index of the element currently addressed within the referenced node
|
909 | field_index_type pos = 0;
|
910 |
|
911 | public:
|
912 | using iterator_category = std::forward_iterator_tag;
|
913 | using value_type = Key;
|
914 | using difference_type = ptrdiff_t;
|
915 | using pointer = value_type*;
|
916 | using reference = value_type&;
|
917 |
|
918 | // default constructor -- creating an end-iterator
|
919 | iterator() : cur(nullptr) {}
|
920 |
|
921 | // creates an iterator referencing a specific element within a given node
|
922 | iterator(node const* cur, field_index_type pos) : cur(cur), pos(pos) {}
|
923 |
|
924 | // a copy constructor
|
925 | iterator(const iterator& other) : cur(other.cur), pos(other.pos) {}
|
926 |
|
927 | // an assignment operator
|
928 | iterator& operator=(const iterator& other) {
|
929 | cur = other.cur;
|
930 | pos = other.pos;
|
931 | return *this;
|
932 | }
|
933 |
|
934 | // the equality operator as required by the iterator concept
|
935 | bool operator==(const iterator& other) const {
|
936 | return cur == other.cur && pos == other.pos;
|
937 | }
|
938 |
|
939 | // the not-equality operator as required by the iterator concept
|
940 | bool operator!=(const iterator& other) const {
|
941 | return !(*this == other);
|
942 | }
|
943 |
|
944 | // the deref operator as required by the iterator concept
|
945 | const Key& operator*() const {
|
946 | return cur->keys[pos];
|
947 | }
|
948 |
|
949 | // the increment operator as required by the iterator concept
|
950 | iterator& operator++() {
|
951 | // the quick mode -- if in a leaf and there are elements left
|
952 | if (cur->isLeaf() && ++pos < cur->getNumElements()) {
|
953 | return *this;
|
954 | }
|
955 |
|
956 | // otherwise it is a bit more tricky
|
957 |
|
958 | // A) currently in an inner node => go to the left-most child
|
959 | if (cur->isInner()) {
|
960 | cur = cur->getChildren()[pos + 1];
|
961 | while (!cur->isLeaf()) {
|
962 | cur = cur->getChildren()[0];
|
963 | }
|
964 | pos = 0;
|
965 |
|
966 | // nodes may be empty due to biased insertion
|
967 | if (!cur->isEmpty()) {
|
968 | return *this;
|
969 | }
|
970 | }
|
971 |
|
972 | // B) we are at the right-most element of a leaf => go to next inner node
|
973 | assert(cur->isLeaf());
|
974 | assert(pos == cur->getNumElements());
|
975 |
|
976 | while (cur != nullptr && pos == cur->getNumElements()) {
|
977 | pos = cur->getPositionInParent();
|
978 | cur = cur->getParent();
|
979 | }
|
980 | return *this;
|
981 | }
|
982 |
|
983 | // prints a textual representation of this iterator to the given stream (mainly for debugging)
|
984 | void print(std::ostream& out = std::cout) const {
|
985 | out << cur << "[" << (int)pos << "]";
|
986 | }
|
987 | };
|
988 |
|
989 | /**
|
990 | * A collection of operation hints speeding up some of the involved operations
|
991 | * by exploiting temporal locality.
|
992 | */
|
993 | template <unsigned size = 1>
|
994 | struct btree_operation_hints {
|
995 | using node_cache = LRUCache<node*, size>;
|
996 |
|
997 | // the node where the last insertion terminated
|
998 | node_cache last_insert;
|
999 |
|
1000 | // the node where the last find-operation terminated
|
1001 | node_cache last_find_end;
|
1002 |
|
1003 | // the node where the last lower-bound operation terminated
|
1004 | node_cache last_lower_bound_end;
|
1005 |
|
1006 | // the node where the last upper-bound operation terminated
|
1007 | node_cache last_upper_bound_end;
|
1008 |
|
1009 | // default constructor
|
1010 | btree_operation_hints() = default;
|
1011 |
|
1012 | // resets all hints (to be triggered e.g. when deleting nodes)
|
1013 | void clear() {
|
1014 | last_insert.clear(nullptr);
|
1015 | last_find_end.clear(nullptr);
|
1016 | last_lower_bound_end.clear(nullptr);
|
1017 | last_upper_bound_end.clear(nullptr);
|
1018 | }
|
1019 | };
|
1020 |
|
1021 | using operation_hints = btree_operation_hints<1>;
|
1022 |
|
1023 | protected:
|
1024 | #ifdef IS_PARALLEL
|
1025 | // a pointer to the root node of this tree
|
1026 | node* volatile root;
|
1027 |
|
1028 | // a lock to synchronize update operations on the root pointer
|
1029 | lock_type root_lock;
|
1030 | #else
|
1031 | // a pointer to the root node of this tree
|
1032 | node* root;
|
1033 |
|
1034 | // required to not duplicate too much code
|
1035 | lock_type root_lock;
|
1036 | #endif
|
1037 |
|
1038 | // a pointer to the left-most node of this tree (initial note for iteration)
|
1039 | leaf_node* leftmost;
|
1040 |
|
1041 | /* -------------- operator hint statistics ----------------- */
|
1042 |
|
1043 | // an aggregation of statistical values of the hint utilization
|
1044 | struct hint_statistics {
|
1045 | // the counter for insertion operations
|
1046 | CacheAccessCounter inserts;
|
1047 |
|
1048 | // the counter for contains operations
|
1049 | CacheAccessCounter contains;
|
1050 |
|
1051 | // the counter for lower_bound operations
|
1052 | CacheAccessCounter lower_bound;
|
1053 |
|
1054 | // the counter for upper_bound operations
|
1055 | CacheAccessCounter upper_bound;
|
1056 | };
|
1057 |
|
1058 | // the hint statistic of this b-tree instance
|
1059 | mutable hint_statistics hint_stats;
|
1060 |
|
1061 | public:
|
1062 | // the maximum number of keys stored per node
|
1063 | static constexpr std::size_t max_keys_per_node = node::maxKeys;
|
1064 |
|
1065 | // -- ctors / dtors --
|
1066 |
|
1067 | // the default constructor creating an empty tree
|
1068 | btree(Comparator comp = Comparator(), WeakComparator weak_comp = WeakComparator())
|
1069 | : comp(std::move(comp)), weak_comp(std::move(weak_comp)), root(nullptr), leftmost(nullptr) {}
|
1070 |
|
1071 | // a constructor creating a tree from the given iterator range
|
1072 | template <typename Iter>
|
1073 | btree(const Iter& a, const Iter& b) : root(nullptr), leftmost(nullptr) {
|
1074 | insert(a, b);
|
1075 | }
|
1076 |
|
1077 | // a move constructor
|
1078 | btree(btree&& other)
|
1079 | : comp(other.comp), weak_comp(other.weak_comp), root(other.root), leftmost(other.leftmost) {
|
1080 | other.root = nullptr;
|
1081 | other.leftmost = nullptr;
|
1082 | }
|
1083 |
|
1084 | // a copy constructor
|
1085 | btree(const btree& set) : comp(set.comp), weak_comp(set.weak_comp), root(nullptr), leftmost(nullptr) {
|
1086 | // use assignment operator for a deep copy
|
1087 | *this = set;
|
1088 | }
|
1089 |
|
1090 | protected:
|
1091 | /**
|
1092 | * An internal constructor enabling the specific creation of a tree
|
1093 | * based on internal parameters.
|
1094 | */
|
1095 | btree(size_type /* size */, node* root, leaf_node* leftmost) : root(root), leftmost(leftmost) {}
|
1096 |
|
1097 | public:
|
1098 | // the destructor freeing all contained nodes
|
1099 | ~btree() {
|
1100 | clear();
|
1101 | }
|
1102 |
|
1103 | // -- mutators and observers --
|
1104 |
|
1105 | // emptiness check
|
1106 | bool empty() const {
|
1107 | return root == nullptr;
|
1108 | }
|
1109 |
|
1110 | // determines the number of elements in this tree
|
1111 | size_type size() const {
|
1112 | return (root) ? root->countEntries() : 0;
|
1113 | }
|
1114 |
|
1115 | /**
|
1116 | * Inserts the given key into this tree.
|
1117 | */
|
1118 | bool insert(const Key& k) {
|
1119 | operation_hints hints;
|
1120 | return insert(k, hints);
|
1121 | }
|
1122 |
|
1123 | /**
|
1124 | * Inserts the given key into this tree.
|
1125 | */
|
1126 | bool insert(const Key& k, operation_hints& hints) {
|
1127 | #ifdef IS_PARALLEL
|
1128 |
|
1129 | // special handling for inserting first element
|
1130 | while (root == nullptr) {
|
1131 | // try obtaining root-lock
|
1132 | if (!root_lock.try_start_write()) {
|
1133 | // somebody else was faster => re-check
|
1134 | continue;
|
1135 | }
|
1136 |
|
1137 | // check loop condition again
|
1138 | if (root != nullptr) {
|
1139 | // somebody else was faster => normal insert
|
1140 | root_lock.end_write();
|
1141 | break;
|
1142 | }
|
1143 |
|
1144 | // create new node
|
1145 | leftmost = new leaf_node();
|
1146 | leftmost->numElements = 1;
|
1147 | leftmost->keys[0] = k;
|
1148 | root = leftmost;
|
1149 |
|
1150 | // operation complete => we can release the root lock
|
1151 | root_lock.end_write();
|
1152 |
|
1153 | hints.last_insert.access(leftmost);
|
1154 |
|
1155 | return true;
|
1156 | }
|
1157 |
|
1158 | // insert using iterative implementation
|
1159 |
|
1160 | node* cur = nullptr;
|
1161 |
|
1162 | // test last insert hints
|
1163 | lock_type::Lease cur_lease;
|
1164 |
|
1165 | auto checkHint = [&](node* last_insert) {
|
1166 | // ignore null pointer
|
1167 | if (!last_insert) return false;
|
1168 | // get a read lease on indicated node
|
1169 | auto hint_lease = last_insert->lock.start_read();
|
1170 | // check whether it covers the key
|
1171 | if (!weak_covers(last_insert, k)) return false;
|
1172 | // and if there was no concurrent modification
|
1173 | if (!last_insert->lock.validate(hint_lease)) return false;
|
1174 | // use hinted location
|
1175 | cur = last_insert;
|
1176 | // and keep lease
|
1177 | cur_lease = hint_lease;
|
1178 | // we found a hit
|
1179 | return true;
|
1180 | };
|
1181 |
|
1182 | if (hints.last_insert.any(checkHint)) {
|
1183 | // register this as a hit
|
1184 | hint_stats.inserts.addHit();
|
1185 | } else {
|
1186 | // register this as a miss
|
1187 | hint_stats.inserts.addMiss();
|
1188 | }
|
1189 |
|
1190 | // if there is no valid hint ..
|
1191 | if (!cur) {
|
1192 | do {
|
1193 | // get root - access lock
|
1194 | auto root_lease = root_lock.start_read();
|
1195 |
|
1196 | // start with root
|
1197 | cur = root;
|
1198 |
|
1199 | // get lease of the next node to be accessed
|
1200 | cur_lease = cur->lock.start_read();
|
1201 |
|
1202 | // check validity of root pointer
|
1203 | if (root_lock.end_read(root_lease)) {
|
1204 | break;
|
1205 | }
|
1206 |
|
1207 | } while (true);
|
1208 | }
|
1209 |
|
1210 | while (true) {
|
1211 | // handle inner nodes
|
1212 | if (cur->inner) {
|
1213 | auto a = &(cur->keys[0]);
|
1214 | auto b = &(cur->keys[cur->numElements]);
|
1215 |
|
1216 | auto pos = search.lower_bound(k, a, b, weak_comp);
|
1217 | auto idx = pos - a;
|
1218 |
|
1219 | // early exit for sets
|
1220 | if (isSet && pos != b && weak_equal(*pos, k)) {
|
1221 | // validate results
|
1222 | if (!cur->lock.validate(cur_lease)) {
|
1223 | // start over again
|
1224 | return insert(k, hints);
|
1225 | }
|
1226 |
|
1227 | // update provenance information
|
1228 | if (typeid(Comparator) != typeid(WeakComparator)) {
|
1229 | if (!cur->lock.try_upgrade_to_write(cur_lease)) {
|
1230 | // start again
|
1231 | return insert(k, hints);
|
1232 | }
|
1233 | bool updated = update(*pos, k);
|
1234 | cur->lock.end_write();
|
1235 | return updated;
|
1236 | }
|
1237 |
|
1238 | // we found the element => no check of lock necessary
|
1239 | return false;
|
1240 | }
|
1241 |
|
1242 | // get next pointer
|
1243 | auto next = cur->getChild(idx);
|
1244 |
|
1245 | // get lease on next level
|
1246 | auto next_lease = next->lock.start_read();
|
1247 |
|
1248 | // check whether there was a write
|
1249 | if (!cur->lock.end_read(cur_lease)) {
|
1250 | // start over
|
1251 | return insert(k, hints);
|
1252 | }
|
1253 |
|
1254 | // go to next
|
1255 | cur = next;
|
1256 |
|
1257 | // move on lease
|
1258 | cur_lease = next_lease;
|
1259 |
|
1260 | continue;
|
1261 | }
|
1262 |
|
1263 | // the rest is for leaf nodes
|
1264 | assert(!cur->inner);
|
1265 |
|
1266 | // -- insert node in leaf node --
|
1267 |
|
1268 | auto a = &(cur->keys[0]);
|
1269 | auto b = &(cur->keys[cur->numElements]);
|
1270 |
|
1271 | auto pos = search.upper_bound(k, a, b, weak_comp);
|
1272 | auto idx = pos - a;
|
1273 |
|
1274 | // early exit for sets
|
1275 | if (isSet && pos != a && weak_equal(*(pos - 1), k)) {
|
1276 | // validate result
|
1277 | if (!cur->lock.validate(cur_lease)) {
|
1278 | // start over again
|
1279 | return insert(k, hints);
|
1280 | }
|
1281 |
|
1282 | // update provenance information
|
1283 | if (typeid(Comparator) != typeid(WeakComparator)) {
|
1284 | if (!cur->lock.try_upgrade_to_write(cur_lease)) {
|
1285 | // start again
|
1286 | return insert(k, hints);
|
1287 | }
|
1288 | bool updated = update(*(pos - 1), k);
|
1289 | cur->lock.end_write();
|
1290 | return updated;
|
1291 | }
|
1292 |
|
1293 | // we found the element => done
|
1294 | return false;
|
1295 | }
|
1296 |
|
1297 | // upgrade to write-permission
|
1298 | if (!cur->lock.try_upgrade_to_write(cur_lease)) {
|
1299 | // something has changed => restart
|
1300 | hints.last_insert.access(cur);
|
1301 | return insert(k, hints);
|
1302 | }
|
1303 |
|
1304 | if (cur->numElements >= node::maxKeys) {
|
1305 | // -- lock parents --
|
1306 | auto priv = cur;
|
1307 | auto parent = priv->parent;
|
1308 | std::vector<node*> parents;
|
1309 | do {
|
1310 | if (parent) {
|
1311 | parent->lock.start_write();
|
1312 | while (true) {
|
1313 | // check whether parent is correct
|
1314 | if (parent == priv->parent) {
|
1315 | break;
|
1316 | }
|
1317 | // switch parent
|
1318 | parent->lock.abort_write();
|
1319 | parent = priv->parent;
|
1320 | parent->lock.start_write();
|
1321 | }
|
1322 | } else {
|
1323 | // lock root lock => since cur is root
|
1324 | root_lock.start_write();
|
1325 | }
|
1326 |
|
1327 | // record locked node
|
1328 | parents.push_back(parent);
|
1329 |
|
1330 | // stop at "sphere of influence"
|
1331 | if (!parent || !parent->isFull()) {
|
1332 | break;
|
1333 | }
|
1334 |
|
1335 | // go one step higher
|
1336 | priv = parent;
|
1337 | parent = parent->parent;
|
1338 |
|
1339 | } while (true);
|
1340 |
|
1341 | // split this node
|
1342 | auto old_root = root;
|
1343 | idx -= cur->rebalance_or_split(
|
1344 | const_cast<node**>(&root), root_lock, static_cast<int>(idx), parents);
|
1345 |
|
1346 | // release parent lock
|
1347 | for (auto it = parents.rbegin(); it != parents.rend(); ++it) {
|
1348 | auto parent = *it;
|
1349 |
|
1350 | // release this lock
|
1351 | if (parent) {
|
1352 | parent->lock.end_write();
|
1353 | } else {
|
1354 | if (old_root != root) {
|
1355 | root_lock.end_write();
|
1356 | } else {
|
1357 | root_lock.abort_write();
|
1358 | }
|
1359 | }
|
1360 | }
|
1361 |
|
1362 | // insert element in right fragment
|
1363 | if (((size_type)idx) > cur->numElements) {
|
1364 | // release current lock
|
1365 | cur->lock.end_write();
|
1366 |
|
1367 | // insert in sibling
|
1368 | return insert(k, hints);
|
1369 | }
|
1370 | }
|
1371 |
|
1372 | // ok - no split necessary
|
1373 | assert(cur->numElements < node::maxKeys && "Split required!");
|
1374 |
|
1375 | // move keys
|
1376 | for (int j = static_cast<int>(cur->numElements); j > static_cast<int>(idx); --j) {
|
1377 | cur->keys[j] = cur->keys[j - 1];
|
1378 | }
|
1379 |
|
1380 | // insert new element
|
1381 | cur->keys[idx] = k;
|
1382 | cur->numElements++;
|
1383 |
|
1384 | // release lock on current node
|
1385 | cur->lock.end_write();
|
1386 |
|
1387 | // remember last insertion position
|
1388 | hints.last_insert.access(cur);
|
1389 | return true;
|
1390 | }
|
1391 |
|
1392 | #else
|
1393 | // special handling for inserting first element
|
1394 | if (empty()) {
|
1395 | // create new node
|
1396 | leftmost = new leaf_node();
|
1397 | leftmost->numElements = 1;
|
1398 | leftmost->keys[0] = k;
|
1399 | root = leftmost;
|
1400 |
|
1401 | hints.last_insert.access(leftmost);
|
1402 |
|
1403 | return true;
|
1404 | }
|
1405 |
|
1406 | // insert using iterative implementation
|
1407 | node* cur = root;
|
1408 |
|
1409 | auto checkHints = [&](node* last_insert) {
|
1410 | if (!last_insert) return false;
|
1411 | if (!weak_covers(last_insert, k)) return false;
|
1412 | cur = last_insert;
|
1413 | return true;
|
1414 | };
|
1415 |
|
1416 | // test last insert
|
1417 | if (hints.last_insert.any(checkHints)) {
|
1418 | hint_stats.inserts.addHit();
|
1419 | } else {
|
1420 | hint_stats.inserts.addMiss();
|
1421 | }
|
1422 |
|
1423 | while (true) {
|
1424 | // handle inner nodes
|
1425 | if (cur->inner) {
|
1426 | auto a = &(cur->keys[0]);
|
1427 | auto b = &(cur->keys[cur->numElements]);
|
1428 |
|
1429 | auto pos = search.lower_bound(k, a, b, weak_comp);
|
1430 | auto idx = pos - a;
|
1431 |
|
1432 | // early exit for sets
|
1433 | if (isSet && pos != b && weak_equal(*pos, k)) {
|
1434 | // update provenance information
|
1435 | if (typeid(Comparator) != typeid(WeakComparator)) {
|
1436 | return update(*pos, k);
|
1437 | }
|
1438 |
|
1439 | return false;
|
1440 | }
|
1441 |
|
1442 | cur = cur->getChild(idx);
|
1443 | continue;
|
1444 | }
|
1445 |
|
1446 | // the rest is for leaf nodes
|
1447 | assert(!cur->inner);
|
1448 |
|
1449 | // -- insert node in leaf node --
|
1450 |
|
1451 | auto a = &(cur->keys[0]);
|
1452 | auto b = &(cur->keys[cur->numElements]);
|
1453 |
|
1454 | auto pos = search.upper_bound(k, a, b, weak_comp);
|
1455 | auto idx = pos - a;
|
1456 |
|
1457 | // early exit for sets
|
1458 | if (isSet && pos != a && weak_equal(*(pos - 1), k)) {
|
1459 | // update provenance information
|
1460 | if (typeid(Comparator) != typeid(WeakComparator)) {
|
1461 | return update(*(pos - 1), k);
|
1462 | }
|
1463 |
|
1464 | return false;
|
1465 | }
|
1466 |
|
1467 | if (cur->numElements >= node::maxKeys) {
|
1468 | // split this node
|
1469 | idx -= cur->rebalance_or_split(&root, root_lock, static_cast<int>(idx));
|
1470 |
|
1471 | // insert element in right fragment
|
1472 | if (((size_type)idx) > cur->numElements) {
|
1473 | idx -= cur->numElements + 1;
|
1474 | cur = cur->parent->getChild(cur->position + 1);
|
1475 | }
|
1476 | }
|
1477 |
|
1478 | // ok - no split necessary
|
1479 | assert(cur->numElements < node::maxKeys && "Split required!");
|
1480 |
|
1481 | // move keys
|
1482 | for (int j = static_cast<int>(cur->numElements); j > idx; --j) {
|
1483 | cur->keys[j] = cur->keys[j - 1];
|
1484 | }
|
1485 |
|
1486 | // insert new element
|
1487 | cur->keys[idx] = k;
|
1488 | cur->numElements++;
|
1489 |
|
1490 | // remember last insertion position
|
1491 | hints.last_insert.access(cur);
|
1492 |
|
1493 | return true;
|
1494 | }
|
1495 | #endif
|
1496 | }
|
1497 |
|
1498 | /**
|
1499 | * Inserts the given range of elements into this tree.
|
1500 | */
|
1501 | template <typename Iter>
|
1502 | void insert(const Iter& a, const Iter& b) {
|
1503 | // TODO: improve this beyond a naive insert
|
1504 | operation_hints hints;
|
1505 | // a naive insert so far .. seems to work fine
|
1506 | for (auto it = a; it != b; ++it) {
|
1507 | // use insert with hint
|
1508 | insert(*it, hints);
|
1509 | }
|
1510 | }
|
1511 |
|
1512 | // Obtains an iterator referencing the first element of the tree.
|
1513 | iterator begin() const {
|
1514 | return iterator(leftmost, 0);
|
1515 | }
|
1516 |
|
1517 | // Obtains an iterator referencing the position after the last element of the tree.
|
1518 | iterator end() const {
|
1519 | return iterator();
|
1520 | }
|
1521 |
|
1522 | /**
|
1523 | * Partitions the full range of this set into up to a given number of chunks.
|
1524 | * The chunks will cover approximately the same number of elements. Also, the
|
1525 | * number of chunks will only approximate the desired number of chunks.
|
1526 | *
|
1527 | * @param num .. the number of chunks requested
|
1528 | * @return a list of chunks partitioning this tree
|
1529 | */
|
1530 | std::vector<chunk> partition(size_type num) const {
|
1531 | return getChunks(num);
|
1532 | }
|
1533 |
|
1534 | std::vector<chunk> getChunks(size_type num) const {
|
1535 | std::vector<chunk> res;
|
1536 | if (empty()) {
|
1537 | return res;
|
1538 | }
|
1539 | return root->collectChunks(res, num, begin(), end());
|
1540 | }
|
1541 |
|
1542 | /**
|
1543 | * Determines whether the given element is a member of this tree.
|
1544 | */
|
1545 | bool contains(const Key& k) const {
|
1546 | operation_hints hints;
|
1547 | return contains(k, hints);
|
1548 | }
|
1549 |
|
1550 | /**
|
1551 | * Determines whether the given element is a member of this tree.
|
1552 | */
|
1553 | bool contains(const Key& k, operation_hints& hints) const {
|
1554 | return find(k, hints) != end();
|
1555 | }
|
1556 |
|
1557 | /**
|
1558 | * Locates the given key within this tree and returns an iterator
|
1559 | * referencing its position. If not found, an end-iterator will be returned.
|
1560 | */
|
1561 | iterator find(const Key& k) const {
|
1562 | operation_hints hints;
|
1563 | return find(k, hints);
|
1564 | }
|
1565 |
|
1566 | /**
|
1567 | * Locates the given key within this tree and returns an iterator
|
1568 | * referencing its position. If not found, an end-iterator will be returned.
|
1569 | */
|
1570 | iterator find(const Key& k, operation_hints& hints) const {
|
1571 | if (empty()) {
|
1572 | return end();
|
1573 | }
|
1574 |
|
1575 | node* cur = root;
|
1576 |
|
1577 | auto checkHints = [&](node* last_find_end) {
|
1578 | if (!last_find_end) return false;
|
1579 | if (!covers(last_find_end, k)) return false;
|
1580 | cur = last_find_end;
|
1581 | return true;
|
1582 | };
|
1583 |
|
1584 | // test last location searched (temporal locality)
|
1585 | if (hints.last_find_end.any(checkHints)) {
|
1586 | // register it as a hit
|
1587 | hint_stats.contains.addHit();
|
1588 | } else {
|
1589 | // register it as a miss
|
1590 | hint_stats.contains.addMiss();
|
1591 | }
|
1592 |
|
1593 | // an iterative implementation (since 2/7 faster than recursive)
|
1594 |
|
1595 | while (true) {
|
1596 | auto a = &(cur->keys[0]);
|
1597 | auto b = &(cur->keys[cur->numElements]);
|
1598 |
|
1599 | auto pos = search(k, a, b, comp);
|
1600 |
|
1601 | if (pos < b && equal(*pos, k)) {
|
1602 | hints.last_find_end.access(cur);
|
1603 | return iterator(cur, static_cast<field_index_type>(pos - a));
|
1604 | }
|
1605 |
|
1606 | if (!cur->inner) {
|
1607 | hints.last_find_end.access(cur);
|
1608 | return end();
|
1609 | }
|
1610 |
|
1611 | // continue search in child node
|
1612 | cur = cur->getChild(pos - a);
|
1613 | }
|
1614 | }
|
1615 |
|
1616 | /**
|
1617 | * Obtains a lower boundary for the given key -- hence an iterator referencing
|
1618 | * the smallest value that is not less the given key. If there is no such element,
|
1619 | * an end-iterator will be returned.
|
1620 | */
|
1621 | iterator lower_bound(const Key& k) const {
|
1622 | operation_hints hints;
|
1623 | return lower_bound(k, hints);
|
1624 | }
|
1625 |
|
1626 | /**
|
1627 | * Obtains a lower boundary for the given key -- hence an iterator referencing
|
1628 | * the smallest value that is not less the given key. If there is no such element,
|
1629 | * an end-iterator will be returned.
|
1630 | */
|
1631 | iterator lower_bound(const Key& k, operation_hints& hints) const {
|
1632 | if (empty()) {
|
1633 | return end();
|
1634 | }
|
1635 |
|
1636 | node* cur = root;
|
1637 |
|
1638 | auto checkHints = [&](node* last_lower_bound_end) {
|
1639 | if (!last_lower_bound_end) return false;
|
1640 | if (!covers(last_lower_bound_end, k)) return false;
|
1641 | cur = last_lower_bound_end;
|
1642 | return true;
|
1643 | };
|
1644 |
|
1645 | // test last searched node
|
1646 | if (hints.last_lower_bound_end.any(checkHints)) {
|
1647 | hint_stats.lower_bound.addHit();
|
1648 | } else {
|
1649 | hint_stats.lower_bound.addMiss();
|
1650 | }
|
1651 |
|
1652 | iterator res = end();
|
1653 | while (true) {
|
1654 | auto a = &(cur->keys[0]);
|
1655 | auto b = &(cur->keys[cur->numElements]);
|
1656 |
|
1657 | auto pos = search.lower_bound(k, a, b, comp);
|
1658 | auto idx = static_cast<field_index_type>(pos - a);
|
1659 |
|
1660 | if (!cur->inner) {
|
1661 | hints.last_lower_bound_end.access(cur);
|
1662 | return (pos != b) ? iterator(cur, idx) : res;
|
1663 | }
|
1664 |
|
1665 | if (isSet && pos != b && equal(*pos, k)) {
|
1666 | return iterator(cur, idx);
|
1667 | }
|
1668 |
|
1669 | if (pos != b) {
|
1670 | res = iterator(cur, idx);
|
1671 | }
|
1672 |
|
1673 | cur = cur->getChild(idx);
|
1674 | }
|
1675 | }
|
1676 |
|
1677 | /**
|
1678 | * Obtains an upper boundary for the given key -- hence an iterator referencing
|
1679 | * the first element that the given key is less than the referenced value. If
|
1680 | * there is no such element, an end-iterator will be returned.
|
1681 | */
|
1682 | iterator upper_bound(const Key& k) const {
|
1683 | operation_hints hints;
|
1684 | return upper_bound(k, hints);
|
1685 | }
|
1686 |
|
1687 | /**
|
1688 | * Obtains an upper boundary for the given key -- hence an iterator referencing
|
1689 | * the first element that the given key is less than the referenced value. If
|
1690 | * there is no such element, an end-iterator will be returned.
|
1691 | */
|
1692 | iterator upper_bound(const Key& k, operation_hints& hints) const {
|
1693 | if (empty()) {
|
1694 | return end();
|
1695 | }
|
1696 |
|
1697 | node* cur = root;
|
1698 |
|
1699 | auto checkHints = [&](node* last_upper_bound_end) {
|
1700 | if (!last_upper_bound_end) return false;
|
1701 | if (!coversUpperBound(last_upper_bound_end, k)) return false;
|
1702 | cur = last_upper_bound_end;
|
1703 | return true;
|
1704 | };
|
1705 |
|
1706 | // test last search node
|
1707 | if (hints.last_upper_bound_end.any(checkHints)) {
|
1708 | hint_stats.upper_bound.addHit();
|
1709 | } else {
|
1710 | hint_stats.upper_bound.addMiss();
|
1711 | }
|
1712 |
|
1713 | iterator res = end();
|
1714 | while (true) {
|
1715 | auto a = &(cur->keys[0]);
|
1716 | auto b = &(cur->keys[cur->numElements]);
|
1717 |
|
1718 | auto pos = search.upper_bound(k, a, b, comp);
|
1719 | auto idx = static_cast<field_index_type>(pos - a);
|
1720 |
|
1721 | if (!cur->inner) {
|
1722 | hints.last_upper_bound_end.access(cur);
|
1723 | return (pos != b) ? iterator(cur, idx) : res;
|
1724 | }
|
1725 |
|
1726 | if (pos != b) {
|
1727 | res = iterator(cur, idx);
|
1728 | }
|
1729 |
|
1730 | cur = cur->getChild(idx);
|
1731 | }
|
1732 | }
|
1733 |
|
1734 | /**
|
1735 | * Clears this tree.
|
1736 | */
|
1737 | void clear() {
|
1738 | if (root != nullptr) {
|
1739 | if (root->isLeaf()) {
|
1740 | delete static_cast<leaf_node*>(root);
|
1741 | } else {
|
1742 | delete static_cast<inner_node*>(root);
|
1743 | }
|
1744 | }
|
1745 | root = nullptr;
|
1746 | leftmost = nullptr;
|
1747 | }
|
1748 |
|
1749 | /**
|
1750 | * Swaps the content of this tree with the given tree. This
|
1751 | * is a much more efficient operation than creating a copy and
|
1752 | * realizing the swap utilizing assignment operations.
|
1753 | */
|
1754 | void swap(btree& other) {
|
1755 | // swap the content
|
1756 | std::swap(root, other.root);
|
1757 | std::swap(leftmost, other.leftmost);
|
1758 | }
|
1759 |
|
1760 | // Implementation of the assignment operation for trees.
|
1761 | btree& operator=(const btree& other) {
|
1762 | // check identity
|
1763 | if (this == &other) {
|
1764 | return *this;
|
1765 | }
|
1766 |
|
1767 | // create a deep-copy of the content of the other tree
|
1768 | // shortcut for empty sets
|
1769 | if (other.empty()) {
|
1770 | return *this;
|
1771 | }
|
1772 |
|
1773 | // clone content (deep copy)
|
1774 | root = other.root->clone();
|
1775 |
|
1776 | // update leftmost reference
|
1777 | auto tmp = root;
|
1778 | while (!tmp->isLeaf()) {
|
1779 | tmp = tmp->getChild(0);
|
1780 | }
|
1781 | leftmost = static_cast<leaf_node*>(tmp);
|
1782 |
|
1783 | // done
|
1784 | return *this;
|
1785 | }
|
1786 |
|
1787 | // Implementation of an equality operation for trees.
|
1788 | bool operator==(const btree& other) const {
|
1789 | // check identity
|
1790 | if (this == &other) {
|
1791 | return true;
|
1792 | }
|
1793 |
|
1794 | // check size
|
1795 | if (size() != other.size()) {
|
1796 | return false;
|
1797 | }
|
1798 | if (size() < other.size()) {
|
1799 | return other == *this;
|
1800 | }
|
1801 |
|
1802 | // check content
|
1803 | for (const auto& key : other) {
|
1804 | if (!contains(key)) {
|
1805 | return false;
|
1806 | }
|
1807 | }
|
1808 | return true;
|
1809 | }
|
1810 |
|
1811 | // Implementation of an inequality operation for trees.
|
1812 | bool operator!=(const btree& other) const {
|
1813 | return !(*this == other);
|
1814 | }
|
1815 |
|
1816 | // -- for debugging --
|
1817 |
|
1818 | // Determines the number of levels contained in this tree.
|
1819 | size_type getDepth() const {
|
1820 | return (empty()) ? 0 : root->getDepth();
|
1821 | }
|
1822 |
|
1823 | // Determines the number of nodes contained in this tree.
|
1824 | size_type getNumNodes() const {
|
1825 | return (empty()) ? 0 : root->countNodes();
|
1826 | }
|
1827 |
|
1828 | // Determines the amount of memory used by this data structure
|
1829 | size_type getMemoryUsage() const {
|
1830 | return sizeof(*this) + (empty() ? 0 : root->getMemoryUsage());
|
1831 | }
|
1832 |
|
1833 | /*
|
1834 | * Prints a textual representation of this tree to the given
|
1835 | * output stream (mostly for debugging and tuning).
|
1836 | */
|
1837 | void printTree(std::ostream& out = std::cout) const {
|
1838 | out << "B-Tree with " << size() << " elements:\n";
|
1839 | if (empty()) {
|
1840 | out << " - empty - \n";
|
1841 | } else {
|
1842 | root->printTree(out, "");
|
1843 | }
|
1844 | }
|
1845 |
|
1846 | /**
|
1847 | * Prints a textual summary of statistical properties of this
|
1848 | * tree to the given output stream (for debugging and tuning).
|
1849 | */
|
1850 | void printStats(std::ostream& out = std::cout) const {
|
1851 | auto nodes = getNumNodes();
|
1852 | out << " ---------------------------------\n";
|
1853 | out << " Elements: " << size() << "\n";
|
1854 | out << " Depth: " << (empty() ? 0 : root->getDepth()) << "\n";
|
1855 | out << " Nodes: " << nodes << "\n";
|
1856 | out << " ---------------------------------\n";
|
1857 | out << " Size of inner node: " << sizeof(inner_node) << "\n";
|
1858 | out << " Size of leaf node: " << sizeof(leaf_node) << "\n";
|
1859 | out << " Size of Key: " << sizeof(Key) << "\n";
|
1860 | out << " max keys / node: " << node::maxKeys << "\n";
|
1861 | out << " avg keys / node: " << (size() / (double)nodes) << "\n";
|
1862 | out << " avg filling rate: " << ((size() / (double)nodes) / node::maxKeys) << "\n";
|
1863 | out << " ---------------------------------\n";
|
1864 | out << " insert-hint (hits/misses/total): " << hint_stats.inserts.getHits() << "/"
|
1865 | << hint_stats.inserts.getMisses() << "/" << hint_stats.inserts.getAccesses() << "\n";
|
1866 | out << " contains-hint(hits/misses/total):" << hint_stats.contains.getHits() << "/"
|
1867 | << hint_stats.contains.getMisses() << "/" << hint_stats.contains.getAccesses() << "\n";
|
1868 | out << " lower-bound-hint (hits/misses/total):" << hint_stats.lower_bound.getHits() << "/"
|
1869 | << hint_stats.lower_bound.getMisses() << "/" << hint_stats.lower_bound.getAccesses() << "\n";
|
1870 | out << " upper-bound-hint (hits/misses/total):" << hint_stats.upper_bound.getHits() << "/"
|
1871 | << hint_stats.upper_bound.getMisses() << "/" << hint_stats.upper_bound.getAccesses() << "\n";
|
1872 | out << " ---------------------------------\n";
|
1873 | }
|
1874 |
|
1875 | /**
|
1876 | * Checks the consistency of this tree.
|
1877 | */
|
1878 | bool check() {
|
1879 | auto ok = empty() || root->check(comp, root);
|
1880 | if (!ok) {
|
1881 | printTree();
|
1882 | }
|
1883 | return ok;
|
1884 | }
|
1885 |
|
1886 | /**
|
1887 | * A static member enabling the bulk-load of ordered data into an empty
|
1888 | * tree. This function is much more efficient in creating a index over
|
1889 | * an ordered set of elements than an iterative insertion of values.
|
1890 | *
|
1891 | * @tparam Iter .. the type of iterator specifying the range
|
1892 | * it must be a random-access iterator
|
1893 | */
|
1894 | template <typename R, typename Iter>
|
1895 | static typename std::enable_if<std::is_same<typename std::iterator_traits<Iter>::iterator_category,
|
1896 | std::random_access_iterator_tag>::value,
|
1897 | R>::type
|
1898 | load(const Iter& a, const Iter& b) {
|
1899 | // quick exit - empty range
|
1900 | if (a == b) {
|
1901 | return R();
|
1902 | }
|
1903 |
|
1904 | // resolve tree recursively
|
1905 | auto root = buildSubTree(a, b - 1);
|
1906 |
|
1907 | // find leftmost node
|
1908 | node* leftmost = root;
|
1909 | while (!leftmost->isLeaf()) {
|
1910 | leftmost = leftmost->getChild(0);
|
1911 | }
|
1912 |
|
1913 | // build result
|
1914 | return R(b - a, root, static_cast<leaf_node*>(leftmost));
|
1915 | }
|
1916 |
|
1917 | protected:
|
1918 | /**
|
1919 | * Determines whether the range covered by the given node is also
|
1920 | * covering the given key value.
|
1921 | */
|
1922 | bool covers(const node* node, const Key& k) const {
|
1923 | if (isSet) {
|
1924 | // in sets we can include the ends as covered elements
|
1925 | return !node->isEmpty() && !less(k, node->keys[0]) && !less(node->keys[node->numElements - 1], k);
|
1926 | }
|
1927 | // in multi-sets the ends may not be completely covered
|
1928 | return !node->isEmpty() && less(node->keys[0], k) && less(k, node->keys[node->numElements - 1]);
|
1929 | }
|
1930 |
|
1931 | /**
|
1932 | * Determines whether the range covered by the given node is also
|
1933 | * covering the given key value.
|
1934 | */
|
1935 | bool weak_covers(const node* node, const Key& k) const {
|
1936 | if (isSet) {
|
1937 | // in sets we can include the ends as covered elements
|
1938 | return !node->isEmpty() && !weak_less(k, node->keys[0]) &&
|
1939 | !weak_less(node->keys[node->numElements - 1], k);
|
1940 | }
|
1941 | // in multi-sets the ends may not be completely covered
|
1942 | return !node->isEmpty() && weak_less(node->keys[0], k) &&
|
1943 | weak_less(k, node->keys[node->numElements - 1]);
|
1944 | }
|
1945 |
|
1946 | private:
|
1947 | /**
|
1948 | * Determines whether the range covered by this node covers
|
1949 | * the upper bound of the given key.
|
1950 | */
|
1951 | bool coversUpperBound(const node* node, const Key& k) const {
|
1952 | // ignore edges
|
1953 | return !node->isEmpty() && !less(k, node->keys[0]) && less(k, node->keys[node->numElements - 1]);
|
1954 | }
|
1955 |
|
1956 | // Utility function for the load operation above.
|
1957 | template <typename Iter>
|
1958 | static node* buildSubTree(const Iter& a, const Iter& b) {
|
1959 | const int N = node::maxKeys;
|
1960 |
|
1961 | // divide range in N+1 sub-ranges
|
1962 | int64_t length = (b - a) + 1;
|
1963 |
|
1964 | // terminal case: length is less then maxKeys
|
1965 | if (length <= N) {
|
1966 | // create a leaf node
|
1967 | node* res = new leaf_node();
|
1968 | res->numElements = length;
|
1969 |
|
1970 | for (int i = 0; i < length; ++i) {
|
1971 | res->keys[i] = a[i];
|
1972 | }
|
1973 |
|
1974 | return res;
|
1975 | }
|
1976 |
|
1977 | // recursive case - compute step size
|
1978 | int numKeys = N;
|
1979 | int64_t step = ((length - numKeys) / (numKeys + 1));
|
1980 |
|
1981 | while (numKeys > 1 && (step < N / 2)) {
|
1982 | numKeys--;
|
1983 | step = ((length - numKeys) / (numKeys + 1));
|
1984 | }
|
1985 |
|
1986 | // create inner node
|
1987 | node* res = new inner_node();
|
1988 | res->numElements = numKeys;
|
1989 |
|
1990 | Iter c = a;
|
1991 | for (int i = 0; i < numKeys; i++) {
|
1992 | // get dividing key
|
1993 | res->keys[i] = c[step];
|
1994 |
|
1995 | // get sub-tree
|
1996 | auto child = buildSubTree(c, c + (step - 1));
|
1997 | child->parent = res;
|
1998 | child->position = i;
|
1999 | res->getChildren()[i] = child;
|
2000 |
|
2001 | c = c + (step + 1);
|
2002 | }
|
2003 |
|
2004 | // and the remaining part
|
2005 | auto child = buildSubTree(c, b);
|
2006 | child->parent = res;
|
2007 | child->position = numKeys;
|
2008 | res->getChildren()[numKeys] = child;
|
2009 |
|
2010 | // done
|
2011 | return res;
|
2012 | }
|
2013 | }; // namespace souffle
|
2014 |
|
2015 | // Instantiation of static member search.
|
2016 | template <typename Key, typename Comparator, typename Allocator, unsigned blockSize, typename SearchStrategy,
|
2017 | bool isSet, typename WeakComparator, typename Updater>
|
2018 | const SearchStrategy
|
2019 | btree<Key, Comparator, Allocator, blockSize, SearchStrategy, isSet, WeakComparator, Updater>::search;
|
2020 |
|
2021 | } // end namespace detail
|
2022 |
|
2023 | /**
|
2024 | * A b-tree based set implementation.
|
2025 | *
|
2026 | * @tparam Key .. the element type to be stored in this set
|
2027 | * @tparam Comparator .. a class defining an order on the stored elements
|
2028 | * @tparam Allocator .. utilized for allocating memory for required nodes
|
2029 | * @tparam blockSize .. determines the number of bytes/block utilized by leaf nodes
|
2030 | * @tparam SearchStrategy .. enables switching between linear, binary or any other search strategy
|
2031 | */
|
2032 | template <typename Key, typename Comparator = detail::comparator<Key>,
|
2033 | typename Allocator = std::allocator<Key>, // is ignored so far
|
2034 | unsigned blockSize = 256,
|
2035 | typename SearchStrategy = typename souffle::detail::default_strategy<Key>::type,
|
2036 | typename WeakComparator = Comparator, typename Updater = souffle::detail::updater<Key>>
|
2037 | class btree_set : public souffle::detail::btree<Key, Comparator, Allocator, blockSize, SearchStrategy, true,
|
2038 | WeakComparator, Updater> {
|
2039 | using super = souffle::detail::btree<Key, Comparator, Allocator, blockSize, SearchStrategy, true,
|
2040 | WeakComparator, Updater>;
|
2041 |
|
2042 | friend class souffle::detail::btree<Key, Comparator, Allocator, blockSize, SearchStrategy, true,
|
2043 | WeakComparator, Updater>;
|
2044 |
|
2045 | public:
|
2046 | /**
|
2047 | * A default constructor creating an empty set.
|
2048 | */
|
2049 | btree_set(const Comparator& comp = Comparator(), const WeakComparator& weak_comp = WeakComparator())
|
2050 | : super(comp, weak_comp) {}
|
2051 |
|
2052 | /**
|
2053 | * A constructor creating a set based on the given range.
|
2054 | */
|
2055 | template <typename Iter>
|
2056 | btree_set(const Iter& a, const Iter& b) {
|
2057 | this->insert(a, b);
|
2058 | }
|
2059 |
|
2060 | // A copy constructor.
|
2061 | btree_set(const btree_set& other) : super(other) {}
|
2062 |
|
2063 | // A move constructor.
|
2064 | btree_set(btree_set&& other) : super(std::move(other)) {}
|
2065 |
|
2066 | private:
|
2067 | // A constructor required by the bulk-load facility.
|
2068 | template <typename s, typename n, typename l>
|
2069 | btree_set(s size, n* root, l* leftmost) : super(size, root, leftmost) {}
|
2070 |
|
2071 | public:
|
2072 | // Support for the assignment operator.
|
2073 | btree_set& operator=(const btree_set& other) {
|
2074 | super::operator=(other);
|
2075 | return *this;
|
2076 | }
|
2077 |
|
2078 | // Support for the bulk-load operator.
|
2079 | template <typename Iter>
|
2080 | static btree_set load(const Iter& a, const Iter& b) {
|
2081 | return super::template load<btree_set>(a, b);
|
2082 | }
|
2083 | };
|
2084 |
|
2085 | /**
|
2086 | * A b-tree based multi-set implementation.
|
2087 | *
|
2088 | * @tparam Key .. the element type to be stored in this set
|
2089 | * @tparam Comparator .. a class defining an order on the stored elements
|
2090 | * @tparam Allocator .. utilized for allocating memory for required nodes
|
2091 | * @tparam blockSize .. determines the number of bytes/block utilized by leaf nodes
|
2092 | * @tparam SearchStrategy .. enables switching between linear, binary or any other search strategy
|
2093 | */
|
2094 | template <typename Key, typename Comparator = detail::comparator<Key>,
|
2095 | typename Allocator = std::allocator<Key>, // is ignored so far
|
2096 | unsigned blockSize = 256,
|
2097 | typename SearchStrategy = typename souffle::detail::default_strategy<Key>::type,
|
2098 | typename WeakComparator = Comparator, typename Updater = souffle::detail::updater<Key>>
|
2099 | class btree_multiset : public souffle::detail::btree<Key, Comparator, Allocator, blockSize, SearchStrategy,
|
2100 | false, WeakComparator, Updater> {
|
2101 | using super = souffle::detail::btree<Key, Comparator, Allocator, blockSize, SearchStrategy, false,
|
2102 | WeakComparator, Updater>;
|
2103 |
|
2104 | friend class souffle::detail::btree<Key, Comparator, Allocator, blockSize, SearchStrategy, false,
|
2105 | WeakComparator, Updater>;
|
2106 |
|
2107 | public:
|
2108 | /**
|
2109 | * A default constructor creating an empty set.
|
2110 | */
|
2111 | btree_multiset(const Comparator& comp = Comparator(), const WeakComparator& weak_comp = WeakComparator())
|
2112 | : super(comp, weak_comp) {}
|
2113 |
|
2114 | /**
|
2115 | * A constructor creating a set based on the given range.
|
2116 | */
|
2117 | template <typename Iter>
|
2118 | btree_multiset(const Iter& a, const Iter& b) {
|
2119 | this->insert(a, b);
|
2120 | }
|
2121 |
|
2122 | // A copy constructor.
|
2123 | btree_multiset(const btree_multiset& other) : super(other) {}
|
2124 |
|
2125 | // A move constructor.
|
2126 | btree_multiset(btree_multiset&& other) : super(std::move(other)) {}
|
2127 |
|
2128 | private:
|
2129 | // A constructor required by the bulk-load facility.
|
2130 | template <typename s, typename n, typename l>
|
2131 | btree_multiset(s size, n* root, l* leftmost) : super(size, root, leftmost) {}
|
2132 |
|
2133 | public:
|
2134 | // Support for the assignment operator.
|
2135 | btree_multiset& operator=(const btree_multiset& other) {
|
2136 | super::operator=(other);
|
2137 | return *this;
|
2138 | }
|
2139 |
|
2140 | // Support for the bulk-load operator.
|
2141 | template <typename Iter>
|
2142 | static btree_multiset load(const Iter& a, const Iter& b) {
|
2143 | return super::template load<btree_multiset>(a, b);
|
2144 | }
|
2145 | };
|
2146 |
|
2147 | } // end of namespace souffle
|