Line data Source code
1 : // Copyright 2010 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #ifndef V8_SPLAY_TREE_H_
6 : #define V8_SPLAY_TREE_H_
7 :
8 : #include "src/allocation.h"
9 :
10 : namespace v8 {
11 : namespace internal {
12 :
13 :
14 : // A splay tree. The config type parameter encapsulates the different
15 : // configurations of a concrete splay tree:
16 : //
17 : // typedef Key: the key type
18 : // typedef Value: the value type
19 : // static const Key kNoKey: the dummy key used when no key is set
20 : // static Value kNoValue(): the dummy value used to initialize nodes
21 : // static int (Compare)(Key& a, Key& b) -> {-1, 0, 1}: comparison function
22 : //
23 : // The tree is also parameterized by an allocation policy
24 : // (Allocator). The policy is used for allocating lists in the C free
25 : // store or the zone; see zone.h.
26 :
27 : // Forward defined as
28 : // template <typename Config, class Allocator = FreeStoreAllocationPolicy>
29 : // class SplayTree;
30 : template <typename Config, class AllocationPolicy>
31 : class SplayTree {
32 : public:
33 : typedef typename Config::Key Key;
34 : typedef typename Config::Value Value;
35 :
36 : class Locator;
37 :
38 : explicit SplayTree(AllocationPolicy allocator = AllocationPolicy())
39 2652 : : root_(nullptr), allocator_(allocator) {}
40 : ~SplayTree();
41 :
42 : V8_INLINE void* operator new(
43 : size_t size, AllocationPolicy allocator = AllocationPolicy()) {
44 : return allocator.New(static_cast<int>(size));
45 : }
46 : V8_INLINE void operator delete(void* p) { AllocationPolicy::Delete(p); }
47 : // Please the MSVC compiler. We should never have to execute this.
48 : V8_INLINE void operator delete(void* p, AllocationPolicy policy) {
49 : UNREACHABLE();
50 : }
51 :
52 : AllocationPolicy allocator() { return allocator_; }
53 :
54 : // Checks if there is a mapping for the key.
55 : bool Contains(const Key& key);
56 :
57 : // Inserts the given key in this tree with the given value. Returns
58 : // true if a node was inserted, otherwise false. If found the locator
59 : // is enabled and provides access to the mapping for the key.
60 : bool Insert(const Key& key, Locator* locator);
61 :
62 : // Looks up the key in this tree and returns true if it was found,
63 : // otherwise false. If the node is found the locator is enabled and
64 : // provides access to the mapping for the key.
65 : bool Find(const Key& key, Locator* locator);
66 :
67 : // Finds the mapping with the greatest key less than or equal to the
68 : // given key.
69 : bool FindGreatestLessThan(const Key& key, Locator* locator);
70 :
71 : // Find the mapping with the greatest key in this tree.
72 : bool FindGreatest(Locator* locator);
73 :
74 : // Finds the mapping with the least key greater than or equal to the
75 : // given key.
76 : bool FindLeastGreaterThan(const Key& key, Locator* locator);
77 :
78 : // Find the mapping with the least key in this tree.
79 : bool FindLeast(Locator* locator);
80 :
81 : // Move the node from one key to another.
82 : bool Move(const Key& old_key, const Key& new_key);
83 :
84 : // Remove the node with the given key from the tree.
85 : bool Remove(const Key& key);
86 :
87 : // Remove all keys from the tree.
88 : void Clear() { ResetRoot(); }
89 :
90 : bool is_empty() { return root_ == nullptr; }
91 :
92 : // Perform the splay operation for the given key. Moves the node with
93 : // the given key to the top of the tree. If no node has the given
94 : // key, the last node on the search path is moved to the top of the
95 : // tree.
96 : void Splay(const Key& key);
97 :
98 : class Node {
99 : public:
100 : Node(const Key& key, const Value& value)
101 1696090 : : key_(key), value_(value), left_(nullptr), right_(nullptr) {}
102 :
103 : V8_INLINE void* operator new(size_t size, AllocationPolicy allocator) {
104 : return allocator.New(static_cast<int>(size));
105 : }
106 : V8_INLINE void operator delete(void* p) {
107 : return AllocationPolicy::Delete(p);
108 : }
109 : // Please the MSVC compiler. We should never have to execute
110 : // this.
111 : V8_INLINE void operator delete(void* p, AllocationPolicy allocator) {
112 : UNREACHABLE();
113 : }
114 :
115 : Key key() { return key_; }
116 : Value value() { return value_; }
117 : Node* left() { return left_; }
118 : Node* right() { return right_; }
119 :
120 : private:
121 : friend class SplayTree;
122 : friend class Locator;
123 : Key key_;
124 : Value value_;
125 : Node* left_;
126 : Node* right_;
127 : };
128 :
129 : // A locator provides access to a node in the tree without actually
130 : // exposing the node.
131 : class Locator {
132 : public:
133 : explicit Locator(Node* node) : node_(node) { }
134 305737 : Locator() : node_(nullptr) {}
135 1230 : const Key& key() { return node_->key_; }
136 307055 : Value& value() { return node_->value_; }
137 163721 : void set_value(const Value& value) { node_->value_ = value; }
138 479273 : inline void bind(Node* node) { node_ = node; }
139 :
140 : private:
141 : Node* node_;
142 : };
143 :
144 : template <class Callback>
145 : void ForEach(Callback* callback);
146 :
147 : protected:
148 : // Resets tree root. Existing nodes become unreachable.
149 2652 : void ResetRoot() { root_ = nullptr; }
150 :
151 : private:
152 : // Search for a node with a given key. If found, root_ points
153 : // to the node.
154 : bool FindInternal(const Key& key);
155 :
156 : // Inserts a node assuming that root_ is already set up.
157 : void InsertInternal(int cmp, Node* node);
158 :
159 : // Removes root_ node.
160 : void RemoveRootNode(const Key& key);
161 :
162 : template <class Callback>
163 : class NodeToPairAdaptor {
164 : public:
165 : explicit NodeToPairAdaptor(Callback* callback)
166 2587 : : callback_(callback) { }
167 161041 : void Call(Node* node) {
168 161041 : callback_->Call(node->key(), node->value());
169 161041 : }
170 :
171 : private:
172 : Callback* callback_;
173 :
174 : DISALLOW_COPY_AND_ASSIGN(NodeToPairAdaptor);
175 : };
176 :
177 : class NodeDeleter {
178 : public:
179 : NodeDeleter() = default;
180 : void Call(Node* node) { AllocationPolicy::Delete(node); }
181 :
182 : private:
183 : DISALLOW_COPY_AND_ASSIGN(NodeDeleter);
184 : };
185 :
186 : template <class Callback>
187 : void ForEachNode(Callback* callback);
188 :
189 : Node* root_;
190 : AllocationPolicy allocator_;
191 :
192 : DISALLOW_COPY_AND_ASSIGN(SplayTree);
193 : };
194 :
195 :
196 : } // namespace internal
197 : } // namespace v8
198 :
199 : #endif // V8_SPLAY_TREE_H_
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