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![Ben Konyi](/assets/img/avatar_default.png)
Change-Id: I02e38f3b80617d0d4ddf398cb94e8ee027d68e0c Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/100889 Reviewed-by: Zach Anderson <zra@google.com>
272 lines
8.2 KiB
C++
272 lines
8.2 KiB
C++
// Copyright (c) 2010, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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//
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// The original file can be found at:
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// https://github.com/v8/v8/blob/master/src/splay-tree-inl.h
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#ifndef RUNTIME_PLATFORM_SPLAY_TREE_INL_H_
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#define RUNTIME_PLATFORM_SPLAY_TREE_INL_H_
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#include <vector>
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#include "platform/splay-tree.h"
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namespace dart {
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template <typename Config, class B, class Allocator>
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SplayTree<Config, B, Allocator>::~SplayTree() {
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NodeDeleter deleter;
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ForEachNode(&deleter);
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::Insert(const Key& key, Locator* locator) {
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if (is_empty()) {
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// If the tree is empty, insert the new node.
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root_ = new (allocator_) Node(key, Config::NoValue());
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} else {
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// Splay on the key to move the last node on the search path
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// for the key to the root of the tree.
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Splay(key);
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// Ignore repeated insertions with the same key.
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int cmp = Config::Compare(key, root_->key_);
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if (cmp == 0) {
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locator->bind(root_);
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return false;
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}
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// Insert the new node.
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Node* node = new (allocator_) Node(key, Config::NoValue());
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InsertInternal(cmp, node);
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}
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locator->bind(root_);
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return true;
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}
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template <typename Config, class B, class Allocator>
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void SplayTree<Config, B, Allocator>::InsertInternal(int cmp, Node* node) {
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if (cmp > 0) {
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node->left_ = root_;
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node->right_ = root_->right_;
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root_->right_ = nullptr;
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} else {
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node->right_ = root_;
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node->left_ = root_->left_;
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root_->left_ = nullptr;
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}
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root_ = node;
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::FindInternal(const Key& key) {
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if (is_empty()) return false;
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Splay(key);
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return Config::Compare(key, root_->key_) == 0;
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::Contains(const Key& key) {
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return FindInternal(key);
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::Find(const Key& key, Locator* locator) {
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if (FindInternal(key)) {
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locator->bind(root_);
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return true;
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} else {
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return false;
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}
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::FindGreatestLessThan(const Key& key,
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Locator* locator) {
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if (is_empty()) return false;
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// Splay on the key to move the node with the given key or the last
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// node on the search path to the top of the tree.
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Splay(key);
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// Now the result is either the root node or the greatest node in
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// the left subtree.
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int cmp = Config::Compare(root_->key_, key);
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if (cmp <= 0) {
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locator->bind(root_);
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return true;
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} else {
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Node* temp = root_;
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root_ = root_->left_;
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bool result = FindGreatest(locator);
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root_ = temp;
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return result;
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}
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::FindLeastGreaterThan(const Key& key,
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Locator* locator) {
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if (is_empty()) return false;
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// Splay on the key to move the node with the given key or the last
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// node on the search path to the top of the tree.
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Splay(key);
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// Now the result is either the root node or the least node in
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// the right subtree.
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int cmp = Config::Compare(root_->key_, key);
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if (cmp >= 0) {
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locator->bind(root_);
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return true;
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} else {
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Node* temp = root_;
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root_ = root_->right_;
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bool result = FindLeast(locator);
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root_ = temp;
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return result;
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}
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::FindGreatest(Locator* locator) {
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if (is_empty()) return false;
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Node* current = root_;
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while (current->right_ != nullptr)
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current = current->right_;
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locator->bind(current);
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return true;
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::FindLeast(Locator* locator) {
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if (is_empty()) return false;
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Node* current = root_;
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while (current->left_ != nullptr)
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current = current->left_;
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locator->bind(current);
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return true;
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::Move(const Key& old_key,
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const Key& new_key) {
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if (!FindInternal(old_key)) return false;
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Node* node_to_move = root_;
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RemoveRootNode(old_key);
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Splay(new_key);
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int cmp = Config::Compare(new_key, root_->key_);
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if (cmp == 0) {
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// A node with the target key already exists.
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delete node_to_move;
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return false;
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}
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node_to_move->key_ = new_key;
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InsertInternal(cmp, node_to_move);
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return true;
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}
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template <typename Config, class B, class Allocator>
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bool SplayTree<Config, B, Allocator>::Remove(const Key& key) {
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if (!FindInternal(key)) return false;
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Node* node_to_remove = root_;
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RemoveRootNode(key);
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delete node_to_remove;
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return true;
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}
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template <typename Config, class B, class Allocator>
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void SplayTree<Config, B, Allocator>::RemoveRootNode(const Key& key) {
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if (root_->left_ == nullptr) {
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// No left child, so the new tree is just the right child.
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root_ = root_->right_;
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} else {
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// Left child exists.
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Node* right = root_->right_;
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// Make the original left child the new root.
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root_ = root_->left_;
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// Splay to make sure that the new root has an empty right child.
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Splay(key);
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// Insert the original right child as the right child of the new
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// root.
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root_->right_ = right;
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}
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}
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template <typename Config, class B, class Allocator>
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void SplayTree<Config, B, Allocator>::Splay(const Key& key) {
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if (is_empty()) return;
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Node dummy_node(Config::kNoKey, Config::NoValue());
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// Create a dummy node. The use of the dummy node is a bit
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// counter-intuitive: The right child of the dummy node will hold
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// the L tree of the algorithm. The left child of the dummy node
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// will hold the R tree of the algorithm. Using a dummy node, left
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// and right will always be nodes and we avoid special cases.
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Node* dummy = &dummy_node;
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Node* left = dummy;
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Node* right = dummy;
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Node* current = root_;
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while (true) {
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int cmp = Config::Compare(key, current->key_);
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if (cmp < 0) {
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if (current->left_ == nullptr) break;
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if (Config::Compare(key, current->left_->key_) < 0) {
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// Rotate right.
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Node* temp = current->left_;
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current->left_ = temp->right_;
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temp->right_ = current;
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current = temp;
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if (current->left_ == nullptr) break;
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}
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// Link right.
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right->left_ = current;
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right = current;
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current = current->left_;
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} else if (cmp > 0) {
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if (current->right_ == nullptr) break;
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if (Config::Compare(key, current->right_->key_) > 0) {
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// Rotate left.
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Node* temp = current->right_;
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current->right_ = temp->left_;
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temp->left_ = current;
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current = temp;
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if (current->right_ == nullptr) break;
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}
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// Link left.
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left->right_ = current;
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left = current;
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current = current->right_;
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} else {
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break;
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}
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}
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// Assemble.
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left->right_ = current->left_;
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right->left_ = current->right_;
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current->left_ = dummy->right_;
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current->right_ = dummy->left_;
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root_ = current;
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}
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template <typename Config, class B, class Allocator>
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template <class Callback>
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void SplayTree<Config, B, Allocator>::ForEach(Callback* callback) {
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NodeToPairAdaptor<Callback> callback_adaptor(callback);
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ForEachNode(&callback_adaptor);
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}
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template <typename Config, class B, class Allocator>
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template <class Callback>
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void SplayTree<Config, B, Allocator>::ForEachNode(Callback* callback) {
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if (root_ == nullptr) return;
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// Pre-allocate some space for tiny trees.
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std::vector<Node*> nodes_to_visit;
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nodes_to_visit.push_back(root_);
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size_t pos = 0;
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while (pos < nodes_to_visit.size()) {
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Node* node = nodes_to_visit[pos++];
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if (node->left() != nullptr) nodes_to_visit.push_back(node->left());
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if (node->right() != nullptr) nodes_to_visit.push_back(node->right());
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callback->Call(node);
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}
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}
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} // namespace dart
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#endif // RUNTIME_PLATFORM_SPLAY_TREE_INL_H_
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