Parametrize C++ splay tree with allocator.

src/splay-tree.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:
+//
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+//     * Redistributions in binary form must reproduce the above
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+//       with the distribution.
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+//       contributors may be used to endorse or promote products derived
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+//
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+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_SPLAY_TREE_H_
+#define V8_SPLAY_TREE_H_
+
+namespace v8 {
+namespace internal {
+
+
+// A splay tree.  The config type parameter encapsulates the different
+// configurations of a concrete splay tree:
+//
+//   typedef Key: the key type
+//   typedef Value: the value type
+//   static const kNoKey: the dummy key used when no key is set
+//   static const kNoValue: the dummy value used to initialize nodes
+//   int (Compare)(Key& a, Key& b) -> {-1, 0, 1}: comparison function
+//
+// The tree is also parameterized by an allocation policy
+// (Allocator). The policy is used for allocating lists in the C free
+// store or the zone; see zone.h.
+
+// Forward defined as
+// template <typename Config, class Allocator = FreeStoreAllocationPolicy>
+//     class SplayTree;
+template <typename Config, class Allocator>
+class SplayTree {
+ public:
+  typedef typename Config::Key Key;
+  typedef typename Config::Value Value;
+
+  class Locator;
+
+  SplayTree() : root_(NULL) { }
+  ~SplayTree();
+
+  INLINE(void* operator new(size_t size)) {
+    return Allocator::New(static_cast<int>(size));
+  }
+  INLINE(void operator delete(void* p, size_t)) { return Allocator::Delete(p); }
+
+  // Inserts the given key in this tree with the given value.  Returns
+  // true if a node was inserted, otherwise false.  If found the locator
+  // is enabled and provides access to the mapping for the key.
+  bool Insert(const Key& key, Locator* locator);
+
+  // Looks up the key in this tree and returns true if it was found,
+  // otherwise false.  If the node is found the locator is enabled and
+  // provides access to the mapping for the key.
+  bool Find(const Key& key, Locator* locator);
+
+  // Finds the mapping with the greatest key less than or equal to the
+  // given key.
+  bool FindGreatestLessThan(const Key& key, Locator* locator);
+
+  // Find the mapping with the greatest key in this tree.
+  bool FindGreatest(Locator* locator);
+
+  // Finds the mapping with the least key greater than or equal to the
+  // given key.
+  bool FindLeastGreaterThan(const Key& key, Locator* locator);
+
+  // Find the mapping with the least key in this tree.
+  bool FindLeast(Locator* locator);
+
+  // Remove the node with the given key from the tree.
+  bool Remove(const Key& key);
+
+  bool is_empty() { return root_ == NULL; }
+
+  // Perform the splay operation for the given key. Moves the node with
+  // the given key to the top of the tree.  If no node has the given
+  // key, the last node on the search path is moved to the top of the
+  // tree.
+  void Splay(const Key& key);
+
+  class Node {
+   public:
+    Node(const Key& key, const Value& value)
+        : key_(key),
+          value_(value),
+          left_(NULL),
+          right_(NULL) { }
+
+    INLINE(void* operator new(size_t size)) {
+      return Allocator::New(static_cast<int>(size));
+    }
+    INLINE(void operator delete(void* p, size_t)) {
+      return Allocator::Delete(p);
+    }
+
+    Key key() { return key_; }
+    Value value() { return value_; }
+    Node* left() { return left_; }
+    Node* right() { return right_; }
+   private:
+
+    friend class SplayTree;
+    friend class Locator;
+    Key key_;
+    Value value_;
+    Node* left_;
+    Node* right_;
+  };
+
+  // A locator provides access to a node in the tree without actually
+  // exposing the node.
+  class Locator BASE_EMBEDDED {
+   public:
+    explicit Locator(Node* node) : node_(node) { }
+    Locator() : node_(NULL) { }
+    const Key& key() { return node_->key_; }
+    Value& value() { return node_->value_; }
+    void set_value(const Value& value) { node_->value_ = value; }
+    inline void bind(Node* node) { node_ = node; }
+   private:
+    Node* node_;
+  };
+
+  template <class Callback>
+  void ForEach(Callback* callback);
+
+ protected:
+
+  // Resets tree root. Existing nodes become unreachable.
+  void ResetRoot() { root_ = NULL; }
+
+ private:
+
+  template<class Callback>
+  class NodeToPairAdaptor BASE_EMBEDDED {
+   public:
+    explicit NodeToPairAdaptor(Callback* callback)
+        : callback_(callback) { }
+    void Call(Node* node) {
+      callback_->Call(node->key(), node->value());
+    }
+
+   private:
+    Callback* callback_;
+
+    DISALLOW_COPY_AND_ASSIGN(NodeToPairAdaptor);
+  };
+
+  class NodeDeleter BASE_EMBEDDED {
+   public:
+    NodeDeleter() { }
+    void Call(Node* node) { delete node; }
+
+   private:
+
+    DISALLOW_COPY_AND_ASSIGN(NodeDeleter);
+  };
+
+  template <class Callback>
+  void ForEachNode(Callback* callback);
+
+  Node* root_;
+
+  DISALLOW_COPY_AND_ASSIGN(SplayTree);
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_SPLAY_TREE_H_