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