1// Copyright 2010 the V8 project authors. All rights reserved.
2// Redistribution and use in source and binary forms, with or without
3// modification, are permitted provided that the following conditions are
4// met:
5//
6//     * Redistributions of source code must retain the above copyright
7//       notice, this list of conditions and the following disclaimer.
8//     * Redistributions in binary form must reproduce the above
9//       copyright notice, this list of conditions and the following
10//       disclaimer in the documentation and/or other materials provided
11//       with the distribution.
12//     * Neither the name of Google Inc. nor the names of its
13//       contributors may be used to endorse or promote products derived
14//       from this software without specific prior written permission.
15//
16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 Key kNoKey: the dummy key used when no key is set
43//   static Value kNoValue(): the dummy value used to initialize nodes
44//   static 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 AllocationPolicy>
54class SplayTree {
55 public:
56  typedef typename Config::Key Key;
57  typedef typename Config::Value Value;
58
59  class Locator;
60
61  SplayTree(AllocationPolicy allocator = AllocationPolicy())
62      : root_(NULL), allocator_(allocator) { }
63  ~SplayTree();
64
65  INLINE(void* operator new(size_t size,
66                            AllocationPolicy allocator = AllocationPolicy())) {
67    return allocator.New(static_cast<int>(size));
68  }
69  INLINE(void operator delete(void* p)) {
70    AllocationPolicy::Delete(p);
71  }
72  // Please the MSVC compiler.  We should never have to execute this.
73  INLINE(void operator delete(void* p, AllocationPolicy policy)) {
74    UNREACHABLE();
75  }
76
77  AllocationPolicy allocator() { return allocator_; }
78
79  // Checks if there is a mapping for the key.
80  bool Contains(const Key& key);
81
82  // Inserts the given key in this tree with the given value.  Returns
83  // true if a node was inserted, otherwise false.  If found the locator
84  // is enabled and provides access to the mapping for the key.
85  bool Insert(const Key& key, Locator* locator);
86
87  // Looks up the key in this tree and returns true if it was found,
88  // otherwise false.  If the node is found the locator is enabled and
89  // provides access to the mapping for the key.
90  bool Find(const Key& key, Locator* locator);
91
92  // Finds the mapping with the greatest key less than or equal to the
93  // given key.
94  bool FindGreatestLessThan(const Key& key, Locator* locator);
95
96  // Find the mapping with the greatest key in this tree.
97  bool FindGreatest(Locator* locator);
98
99  // Finds the mapping with the least key greater than or equal to the
100  // given key.
101  bool FindLeastGreaterThan(const Key& key, Locator* locator);
102
103  // Find the mapping with the least key in this tree.
104  bool FindLeast(Locator* locator);
105
106  // Move the node from one key to another.
107  bool Move(const Key& old_key, const Key& new_key);
108
109  // Remove the node with the given key from the tree.
110  bool Remove(const Key& key);
111
112  // Remove all keys from the tree.
113  void Clear() { ResetRoot(); }
114
115  bool is_empty() { return root_ == NULL; }
116
117  // Perform the splay operation for the given key. Moves the node with
118  // the given key to the top of the tree.  If no node has the given
119  // key, the last node on the search path is moved to the top of the
120  // tree.
121  void Splay(const Key& key);
122
123  class Node {
124   public:
125    Node(const Key& key, const Value& value)
126        : key_(key),
127          value_(value),
128          left_(NULL),
129          right_(NULL) { }
130
131    INLINE(void* operator new(size_t size, AllocationPolicy allocator)) {
132      return allocator.New(static_cast<int>(size));
133    }
134    INLINE(void operator delete(void* p)) {
135      return AllocationPolicy::Delete(p);
136    }
137    // Please the MSVC compiler.  We should never have to execute
138    // this.
139    INLINE(void operator delete(void* p, AllocationPolicy allocator)) {
140      UNREACHABLE();
141    }
142
143    Key key() { return key_; }
144    Value value() { return value_; }
145    Node* left() { return left_; }
146    Node* right() { return right_; }
147
148   private:
149    friend class SplayTree;
150    friend class Locator;
151    Key key_;
152    Value value_;
153    Node* left_;
154    Node* right_;
155  };
156
157  // A locator provides access to a node in the tree without actually
158  // exposing the node.
159  class Locator BASE_EMBEDDED {
160   public:
161    explicit Locator(Node* node) : node_(node) { }
162    Locator() : node_(NULL) { }
163    const Key& key() { return node_->key_; }
164    Value& value() { return node_->value_; }
165    void set_value(const Value& value) { node_->value_ = value; }
166    inline void bind(Node* node) { node_ = node; }
167
168   private:
169    Node* node_;
170  };
171
172  template <class Callback>
173  void ForEach(Callback* callback);
174
175 protected:
176  // Resets tree root. Existing nodes become unreachable.
177  void ResetRoot() { root_ = NULL; }
178
179 private:
180  // Search for a node with a given key. If found, root_ points
181  // to the node.
182  bool FindInternal(const Key& key);
183
184  // Inserts a node assuming that root_ is already set up.
185  void InsertInternal(int cmp, Node* node);
186
187  // Removes root_ node.
188  void RemoveRootNode(const Key& key);
189
190  template<class Callback>
191  class NodeToPairAdaptor BASE_EMBEDDED {
192   public:
193    explicit NodeToPairAdaptor(Callback* callback)
194        : callback_(callback) { }
195    void Call(Node* node) {
196      callback_->Call(node->key(), node->value());
197    }
198
199   private:
200    Callback* callback_;
201
202    DISALLOW_COPY_AND_ASSIGN(NodeToPairAdaptor);
203  };
204
205  class NodeDeleter BASE_EMBEDDED {
206   public:
207    NodeDeleter() { }
208    void Call(Node* node) { AllocationPolicy::Delete(node); }
209
210   private:
211    DISALLOW_COPY_AND_ASSIGN(NodeDeleter);
212  };
213
214  template <class Callback>
215  void ForEachNode(Callback* callback);
216
217  Node* root_;
218  AllocationPolicy allocator_;
219
220  DISALLOW_COPY_AND_ASSIGN(SplayTree);
221};
222
223
224} }  // namespace v8::internal
225
226#endif  // V8_SPLAY_TREE_H_
227