Parametrize C++ splay tree with allocator.

src/splay-tree-inl.h

+// 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
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+// (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);
+    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;
+  }
+  locator->bind(root_);
+  return true;
+}
+
+
+template<typename Config, class Allocator>
+bool SplayTree<Config, Allocator>::Find(const Key& key, Locator* locator) {
+  if (is_empty())
+    return false;
+  Splay(key);
+  if (Config::Compare(key, root_->key_) == 0) {
+    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>::Remove(const Key& key) {
+  // Bail if the tree is empty
+  if (is_empty())
+    return false;
+  // Splay on the key to move the node with the given key to the top.
+  Splay(key);
+  // Bail if the key is not in the tree
+  if (Config::Compare(key, root_->key_) != 0)
+    return false;
+  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;
+  }
+  return true;
+}
+
+
+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_