summaryrefslogtreecommitdiff
path: root/deps/v8/src/splay-tree-inl.h
blob: 9c2287eab7e98ca7c25401f8ed16635faa603698 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef V8_SPLAY_TREE_INL_H_
#define V8_SPLAY_TREE_INL_H_

#include "splay-tree.h"

namespace v8 {
namespace internal {


template<typename Config, class Allocator>
SplayTree<Config, Allocator>::~SplayTree() {
  NodeDeleter deleter;
  ForEachNode(&deleter);
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::Insert(const Key& key, Locator* locator) {
  if (is_empty()) {
    // If the tree is empty, insert the new node.
    root_ = new Node(key, Config::kNoValue);
  } else {
    // Splay on the key to move the last node on the search path
    // for the key to the root of the tree.
    Splay(key);
    // Ignore repeated insertions with the same key.
    int cmp = Config::Compare(key, root_->key_);
    if (cmp == 0) {
      locator->bind(root_);
      return false;
    }
    // Insert the new node.
    Node* node = new Node(key, Config::kNoValue);
    InsertInternal(cmp, node);
  }
  locator->bind(root_);
  return true;
}


template<typename Config, class Allocator>
void SplayTree<Config, Allocator>::InsertInternal(int cmp, Node* node) {
  if (cmp > 0) {
    node->left_ = root_;
    node->right_ = root_->right_;
    root_->right_ = NULL;
  } else {
    node->right_ = root_;
    node->left_ = root_->left_;
    root_->left_ = NULL;
  }
  root_ = node;
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindInternal(const Key& key) {
  if (is_empty())
    return false;
  Splay(key);
  return Config::Compare(key, root_->key_) == 0;
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::Find(const Key& key, Locator* locator) {
  if (FindInternal(key)) {
    locator->bind(root_);
    return true;
  } else {
    return false;
  }
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindGreatestLessThan(const Key& key,
                                                        Locator* locator) {
  if (is_empty())
    return false;
  // Splay on the key to move the node with the given key or the last
  // node on the search path to the top of the tree.
  Splay(key);
  // Now the result is either the root node or the greatest node in
  // the left subtree.
  int cmp = Config::Compare(root_->key_, key);
  if (cmp <= 0) {
    locator->bind(root_);
    return true;
  } else {
    Node* temp = root_;
    root_ = root_->left_;
    bool result = FindGreatest(locator);
    root_ = temp;
    return result;
  }
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindLeastGreaterThan(const Key& key,
                                                        Locator* locator) {
  if (is_empty())
    return false;
  // Splay on the key to move the node with the given key or the last
  // node on the search path to the top of the tree.
  Splay(key);
  // Now the result is either the root node or the least node in
  // the right subtree.
  int cmp = Config::Compare(root_->key_, key);
  if (cmp >= 0) {
    locator->bind(root_);
    return true;
  } else {
    Node* temp = root_;
    root_ = root_->right_;
    bool result = FindLeast(locator);
    root_ = temp;
    return result;
  }
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindGreatest(Locator* locator) {
  if (is_empty())
    return false;
  Node* current = root_;
  while (current->right_ != NULL)
    current = current->right_;
  locator->bind(current);
  return true;
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::FindLeast(Locator* locator) {
  if (is_empty())
    return false;
  Node* current = root_;
  while (current->left_ != NULL)
    current = current->left_;
  locator->bind(current);
  return true;
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::Move(const Key& old_key,
                                        const Key& new_key) {
  if (!FindInternal(old_key))
    return false;
  Node* node_to_move = root_;
  RemoveRootNode(old_key);
  Splay(new_key);
  int cmp = Config::Compare(new_key, root_->key_);
  if (cmp == 0) {
    // A node with the target key already exists.
    delete node_to_move;
    return false;
  }
  node_to_move->key_ = new_key;
  InsertInternal(cmp, node_to_move);
  return true;
}


template<typename Config, class Allocator>
bool SplayTree<Config, Allocator>::Remove(const Key& key) {
  if (!FindInternal(key))
    return false;
  Node* node_to_remove = root_;
  RemoveRootNode(key);
  delete node_to_remove;
  return true;
}


template<typename Config, class Allocator>
void SplayTree<Config, Allocator>::RemoveRootNode(const Key& key) {
  if (root_->left_ == NULL) {
    // No left child, so the new tree is just the right child.
    root_ = root_->right_;
  } else {
    // Left child exists.
    Node* right = root_->right_;
    // Make the original left child the new root.
    root_ = root_->left_;
    // Splay to make sure that the new root has an empty right child.
    Splay(key);
    // Insert the original right child as the right child of the new
    // root.
    root_->right_ = right;
  }
}


template<typename Config, class Allocator>
void SplayTree<Config, Allocator>::Splay(const Key& key) {
  if (is_empty())
    return;
  Node dummy_node(Config::kNoKey, Config::kNoValue);
  // Create a dummy node.  The use of the dummy node is a bit
  // counter-intuitive: The right child of the dummy node will hold
  // the L tree of the algorithm.  The left child of the dummy node
  // will hold the R tree of the algorithm.  Using a dummy node, left
  // and right will always be nodes and we avoid special cases.
  Node* dummy = &dummy_node;
  Node* left = dummy;
  Node* right = dummy;
  Node* current = root_;
  while (true) {
    int cmp = Config::Compare(key, current->key_);
    if (cmp < 0) {
      if (current->left_ == NULL)
        break;
      if (Config::Compare(key, current->left_->key_) < 0) {
        // Rotate right.
        Node* temp = current->left_;
        current->left_ = temp->right_;
        temp->right_ = current;
        current = temp;
        if (current->left_ == NULL)
          break;
      }
      // Link right.
      right->left_ = current;
      right = current;
      current = current->left_;
    } else if (cmp > 0) {
      if (current->right_ == NULL)
        break;
      if (Config::Compare(key, current->right_->key_) > 0) {
        // Rotate left.
        Node* temp = current->right_;
        current->right_ = temp->left_;
        temp->left_ = current;
        current = temp;
        if (current->right_ == NULL)
          break;
      }
      // Link left.
      left->right_ = current;
      left = current;
      current = current->right_;
    } else {
      break;
    }
  }
  // Assemble.
  left->right_ = current->left_;
  right->left_ = current->right_;
  current->left_ = dummy->right_;
  current->right_ = dummy->left_;
  root_ = current;
}


template <typename Config, class Allocator> template <class Callback>
void SplayTree<Config, Allocator>::ForEach(Callback* callback) {
  NodeToPairAdaptor<Callback> callback_adaptor(callback);
  ForEachNode(&callback_adaptor);
}


template <typename Config, class Allocator> template <class Callback>
void SplayTree<Config, Allocator>::ForEachNode(Callback* callback) {
  // Pre-allocate some space for tiny trees.
  List<Node*, Allocator> nodes_to_visit(10);
  if (root_ != NULL) nodes_to_visit.Add(root_);
  int pos = 0;
  while (pos < nodes_to_visit.length()) {
    Node* node = nodes_to_visit[pos++];
    if (node->left() != NULL) nodes_to_visit.Add(node->left());
    if (node->right() != NULL) nodes_to_visit.Add(node->right());
    callback->Call(node);
  }
}


} }  // namespace v8::internal

#endif  // V8_SPLAY_TREE_INL_H_