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// Copyright (c) 2010, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// The original file can be found at:
#include "platform/allocation.h"
namespace dart {
// A splay tree. The config type parameter encapsulates the different
// configurations of a concrete splay tree:
// typedef Key: the key type
// typedef Value: the value type
// static const Key kNoKey: the dummy key used when no key is set
// static Value kNoValue(): the dummy value used to initialize nodes
// static int (Compare)(Key& a, Key& b) -> {-1, 0, 1}: comparison function
// The tree is also parameterized by an allocation policy
// (Allocator). The policy is used for allocating lists in the C free
// store or the zone; see zone.h.
template <typename Config, class B, class Allocator>
class SplayTree : public B {
typedef typename Config::Key Key;
typedef typename Config::Value Value;
class Locator;
explicit SplayTree(Allocator* allocator)
: root_(nullptr), allocator_(allocator) {}
Allocator* allocator() { return allocator_; }
// Checks if there is a mapping for the key.
bool Contains(const Key& key);
// Inserts the given key in this tree with the given value. Returns
// true if a node was inserted, otherwise false. If found the locator
// is enabled and provides access to the mapping for the key.
bool Insert(const Key& key, Locator* locator);
// Looks up the key in this tree and returns true if it was found,
// otherwise false. If the node is found the locator is enabled and
// provides access to the mapping for the key.
bool Find(const Key& key, Locator* locator);
// Finds the mapping with the greatest key less than or equal to the
// given key.
bool FindGreatestLessThan(const Key& key, Locator* locator);
// Find the mapping with the greatest key in this tree.
bool FindGreatest(Locator* locator);
// Finds the mapping with the least key greater than or equal to the
// given key.
bool FindLeastGreaterThan(const Key& key, Locator* locator);
// Find the mapping with the least key in this tree.
bool FindLeast(Locator* locator);
// Move the node from one key to another.
bool Move(const Key& old_key, const Key& new_key);
// Remove the node with the given key from the tree.
bool Remove(const Key& key);
// Remove all keys from the tree.
void Clear() { ResetRoot(); }
bool is_empty() { return root_ == nullptr; }
// Perform the splay operation for the given key. Moves the node with
// the given key to the top of the tree. If no node has the given
// key, the last node on the search path is moved to the top of the
// tree.
void Splay(const Key& key);
class Node : public B {
Node(const Key& key, const Value& value)
: key_(key), value_(value), left_(nullptr), right_(nullptr) {}
Key key() { return key_; }
Value value() { return value_; }
Node* left() { return left_; }
Node* right() { return right_; }
friend class SplayTree;
friend class Locator;
Key key_;
Value value_;
Node* left_;
Node* right_;
// A locator provides access to a node in the tree without actually
// exposing the node.
class Locator : public B {
explicit Locator(Node* node) : node_(node) {}
Locator() : node_(nullptr) {}
const Key& key() { return node_->key_; }
Value& value() { return node_->value_; }
void set_value(const Value& value) { node_->value_ = value; }
inline void bind(Node* node) { node_ = node; }
Node* node_;
template <class Callback>
void ForEach(Callback* callback);
// Resets tree root. Existing nodes become unreachable.
void ResetRoot() { root_ = nullptr; }
// Search for a node with a given key. If found, root_ points
// to the node.
bool FindInternal(const Key& key);
// Inserts a node assuming that root_ is already set up.
void InsertInternal(int cmp, Node* node);
// Removes root_ node.
void RemoveRootNode(const Key& key);
template <class Callback>
class NodeToPairAdaptor : public B {
explicit NodeToPairAdaptor(Callback* callback) : callback_(callback) {}
void Call(Node* node) { callback_->Call(node->key(), node->value()); }
Callback* callback_;
class NodeDeleter : public B {
NodeDeleter() = default;
void Call(Node* node) { delete node; }
template <class Callback>
void ForEachNode(Callback* callback);
Node* root_;
Allocator* allocator_;
} // namespace dart