root/src/splay-tree-inl.h
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// Copyright 2010 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
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//
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#ifndef V8_SPLAY_TREE_INL_H_
#define V8_SPLAY_TREE_INL_H_
#include "splay-tree.h"
namespace v8 {
namespace internal {
template<typename Config, class Allocator>
SplayTree<Config, Allocator>::~SplayTree() {
NodeDeleter deleter;
ForEachNode(&deleter);
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::Insert(const Key& key,
Locator* locator) {
if (is_empty()) {
// If the tree is empty, insert the new node.
root_ = new(allocator_) Node(key, Config::NoValue());
} else {
// Splay on the key to move the last node on the search path
// for the key to the root of the tree.
Splay(key);
// Ignore repeated insertions with the same key.
int cmp = Config::Compare(key, root_->key_);
if (cmp == 0) {
locator->bind(root_);
return false;
}
// Insert the new node.
Node* node = new(allocator_) Node(key, Config::NoValue());
InsertInternal(cmp, node);
}
locator->bind(root_);
return true;
}
template<typename Config, class Allocator>
void SplayTree<Config, Allocator>::InsertInternal(int cmp, Node* node) {
if (cmp > 0) {
node->left_ = root_;
node->right_ = root_->right_;
root_->right_ = NULL;
} else {
node->right_ = root_;
node->left_ = root_->left_;
root_->left_ = NULL;
}
root_ = node;
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindInternal(const Key& key) {
if (is_empty())
return false;
Splay(key);
return Config::Compare(key, root_->key_) == 0;
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::Find(const Key& key, Locator* locator) {
if (FindInternal(key)) {
locator->bind(root_);
return true;
} else {
return false;
}
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindGreatestLessThan(const Key& key,
Locator* locator) {
if (is_empty())
return false;
// Splay on the key to move the node with the given key or the last
// node on the search path to the top of the tree.
Splay(key);
// Now the result is either the root node or the greatest node in
// the left subtree.
int cmp = Config::Compare(root_->key_, key);
if (cmp <= 0) {
locator->bind(root_);
return true;
} else {
Node* temp = root_;
root_ = root_->left_;
bool result = FindGreatest(locator);
root_ = temp;
return result;
}
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindLeastGreaterThan(const Key& key,
Locator* locator) {
if (is_empty())
return false;
// Splay on the key to move the node with the given key or the last
// node on the search path to the top of the tree.
Splay(key);
// Now the result is either the root node or the least node in
// the right subtree.
int cmp = Config::Compare(root_->key_, key);
if (cmp >= 0) {
locator->bind(root_);
return true;
} else {
Node* temp = root_;
root_ = root_->right_;
bool result = FindLeast(locator);
root_ = temp;
return result;
}
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindGreatest(Locator* locator) {
if (is_empty())
return false;
Node* current = root_;
while (current->right_ != NULL)
current = current->right_;
locator->bind(current);
return true;
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindLeast(Locator* locator) {
if (is_empty())
return false;
Node* current = root_;
while (current->left_ != NULL)
current = current->left_;
locator->bind(current);
return true;
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::Move(const Key& old_key,
const Key& new_key) {
if (!FindInternal(old_key))
return false;
Node* node_to_move = root_;
RemoveRootNode(old_key);
Splay(new_key);
int cmp = Config::Compare(new_key, root_->key_);
if (cmp == 0) {
// A node with the target key already exists.
delete node_to_move;
return false;
}
node_to_move->key_ = new_key;
InsertInternal(cmp, node_to_move);
return true;
}
template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::Remove(const Key& key) {
if (!FindInternal(key))
return false;
Node* node_to_remove = root_;
RemoveRootNode(key);
delete node_to_remove;
return true;
}
template<typename Config, class Allocator>
void SplayTree<Config, Allocator>::RemoveRootNode(const Key& key) {
if (root_->left_ == NULL) {
// No left child, so the new tree is just the right child.
root_ = root_->right_;
} else {
// Left child exists.
Node* right = root_->right_;
// Make the original left child the new root.
root_ = root_->left_;
// Splay to make sure that the new root has an empty right child.
Splay(key);
// Insert the original right child as the right child of the new
// root.
root_->right_ = right;
}
}
template<typename Config, class Allocator>
void SplayTree<Config, Allocator>::Splay(const Key& key) {
if (is_empty())
return;
Node dummy_node(Config::kNoKey, Config::NoValue());
// Create a dummy node. The use of the dummy node is a bit
// counter-intuitive: The right child of the dummy node will hold
// the L tree of the algorithm. The left child of the dummy node
// will hold the R tree of the algorithm. Using a dummy node, left
// and right will always be nodes and we avoid special cases.
Node* dummy = &dummy_node;
Node* left = dummy;
Node* right = dummy;
Node* current = root_;
while (true) {
int cmp = Config::Compare(key, current->key_);
if (cmp < 0) {
if (current->left_ == NULL)
break;
if (Config::Compare(key, current->left_->key_) < 0) {
// Rotate right.
Node* temp = current->left_;
current->left_ = temp->right_;
temp->right_ = current;
current = temp;
if (current->left_ == NULL)
break;
}
// Link right.
right->left_ = current;
right = current;
current = current->left_;
} else if (cmp > 0) {
if (current->right_ == NULL)
break;
if (Config::Compare(key, current->right_->key_) > 0) {
// Rotate left.
Node* temp = current->right_;
current->right_ = temp->left_;
temp->left_ = current;
current = temp;
if (current->right_ == NULL)
break;
}
// Link left.
left->right_ = current;
left = current;
current = current->right_;
} else {
break;
}
}
// Assemble.
left->right_ = current->left_;
right->left_ = current->right_;
current->left_ = dummy->right_;
current->right_ = dummy->left_;
root_ = current;
}
template <typename Config, class Allocator> template <class Callback>
void SplayTree<Config, Allocator>::ForEach(Callback* callback) {
NodeToPairAdaptor<Callback> callback_adaptor(callback);
ForEachNode(&callback_adaptor);
}
template <typename Config, class Allocator> template <class Callback>
void SplayTree<Config, Allocator>::ForEachNode(Callback* callback) {
// Pre-allocate some space for tiny trees.
List<Node*, Allocator> nodes_to_visit(10, allocator_);
if (root_ != NULL) nodes_to_visit.Add(root_, allocator_);
int pos = 0;
while (pos < nodes_to_visit.length()) {
Node* node = nodes_to_visit[pos++];
if (node->left() != NULL) nodes_to_visit.Add(node->left(), allocator_);
if (node->right() != NULL) nodes_to_visit.Add(node->right(), allocator_);
callback->Call(node);
}
}
} } // namespace v8::internal
#endif // V8_SPLAY_TREE_INL_H_