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27
28#ifndef V8_SPLAY_TREE_H_
29#define V8_SPLAY_TREE_H_
30
31#include "allocation.h"
32
33namespace v8 {
34namespace internal {
35
36
37// A splay tree.  The config type parameter encapsulates the different
38// configurations of a concrete splay tree:
39//
40//   typedef Key: the key type
41//   typedef Value: the value type
42//   static const kNoKey: the dummy key used when no key is set
43//   static const kNoValue: the dummy value used to initialize nodes
44//   int (Compare)(Key& a, Key& b) -> {-1, 0, 1}: comparison function
45//
46// The tree is also parameterized by an allocation policy
47// (Allocator). The policy is used for allocating lists in the C free
48// store or the zone; see zone.h.
49
50// Forward defined as
51// template <typename Config, class Allocator = FreeStoreAllocationPolicy>
52//     class SplayTree;
53template <typename Config, class Allocator>
54class SplayTree {
55 public:
56  typedef typename Config::Key Key;
57  typedef typename Config::Value Value;
58
59  class Locator;
60
61  SplayTree() : root_(NULL) { }
62  ~SplayTree();
63
64  INLINE(void* operator new(size_t size)) {
65    return Allocator::New(static_cast<int>(size));
66  }
67  INLINE(void operator delete(void* p, size_t)) { return Allocator::Delete(p); }
68
69  // Inserts the given key in this tree with the given value.  Returns
70  // true if a node was inserted, otherwise false.  If found the locator
71  // is enabled and provides access to the mapping for the key.
72  bool Insert(const Key& key, Locator* locator);
73
74  // Looks up the key in this tree and returns true if it was found,
75  // otherwise false.  If the node is found the locator is enabled and
76  // provides access to the mapping for the key.
77  bool Find(const Key& key, Locator* locator);
78
79  // Finds the mapping with the greatest key less than or equal to the
80  // given key.
81  bool FindGreatestLessThan(const Key& key, Locator* locator);
82
83  // Find the mapping with the greatest key in this tree.
84  bool FindGreatest(Locator* locator);
85
86  // Finds the mapping with the least key greater than or equal to the
87  // given key.
88  bool FindLeastGreaterThan(const Key& key, Locator* locator);
89
90  // Find the mapping with the least key in this tree.
91  bool FindLeast(Locator* locator);
92
93  // Move the node from one key to another.
94  bool Move(const Key& old_key, const Key& new_key);
95
96  // Remove the node with the given key from the tree.
97  bool Remove(const Key& key);
98
99  bool is_empty() { return root_ == NULL; }
100
101  // Perform the splay operation for the given key. Moves the node with
102  // the given key to the top of the tree.  If no node has the given
103  // key, the last node on the search path is moved to the top of the
104  // tree.
105  void Splay(const Key& key);
106
107  class Node {
108   public:
109    Node(const Key& key, const Value& value)
110        : key_(key),
111          value_(value),
112          left_(NULL),
113          right_(NULL) { }
114
115    INLINE(void* operator new(size_t size)) {
116      return Allocator::New(static_cast<int>(size));
117    }
118    INLINE(void operator delete(void* p, size_t)) {
119      return Allocator::Delete(p);
120    }
121
122    Key key() { return key_; }
123    Value value() { return value_; }
124    Node* left() { return left_; }
125    Node* right() { return right_; }
126
127   private:
128    friend class SplayTree;
129    friend class Locator;
130    Key key_;
131    Value value_;
132    Node* left_;
133    Node* right_;
134  };
135
136  // A locator provides access to a node in the tree without actually
137  // exposing the node.
138  class Locator BASE_EMBEDDED {
139   public:
140    explicit Locator(Node* node) : node_(node) { }
141    Locator() : node_(NULL) { }
142    const Key& key() { return node_->key_; }
143    Value& value() { return node_->value_; }
144    void set_value(const Value& value) { node_->value_ = value; }
145    inline void bind(Node* node) { node_ = node; }
146
147   private:
148    Node* node_;
149  };
150
151  template <class Callback>
152  void ForEach(Callback* callback);
153
154 protected:
155  // Resets tree root. Existing nodes become unreachable.
156  void ResetRoot() { root_ = NULL; }
157
158 private:
159  // Search for a node with a given key. If found, root_ points
160  // to the node.
161  bool FindInternal(const Key& key);
162
163  // Inserts a node assuming that root_ is already set up.
164  void InsertInternal(int cmp, Node* node);
165
166  // Removes root_ node.
167  void RemoveRootNode(const Key& key);
168
169  template<class Callback>
170  class NodeToPairAdaptor BASE_EMBEDDED {
171   public:
172    explicit NodeToPairAdaptor(Callback* callback)
173        : callback_(callback) { }
174    void Call(Node* node) {
175      callback_->Call(node->key(), node->value());
176    }
177
178   private:
179    Callback* callback_;
180
181    DISALLOW_COPY_AND_ASSIGN(NodeToPairAdaptor);
182  };
183
184  class NodeDeleter BASE_EMBEDDED {
185   public:
186    NodeDeleter() { }
187    void Call(Node* node) { delete node; }
188
189   private:
190    DISALLOW_COPY_AND_ASSIGN(NodeDeleter);
191  };
192
193  template <class Callback>
194  void ForEachNode(Callback* callback);
195
196  Node* root_;
197
198  DISALLOW_COPY_AND_ASSIGN(SplayTree);
199};
200
201
202} }  // namespace v8::internal
203
204#endif  // V8_SPLAY_TREE_H_
205