--- /dev/null
+// Copyright 2009 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.
+
+// This benchmark is based on a JavaScript log processing module used
+// by the V8 profiler to generate execution time profiles for runs of
+// JavaScript applications, and it effectively measures how fast the
+// JavaScript engine is at allocating nodes and reclaiming the memory
+// used for old nodes. Because of the way splay trees work, the engine
+// also has to deal with a lot of changes to the large tree object
+// graph.
+
+// Configuration.
+var kSplayTreeSize = 8000;
+var kSplayTreeModifications = 80;
+var kSplayTreePayloadDepth = 5;
+
+var splayTree = null;
+
+
+function GeneratePayloadTree(depth, tag) {
+ if (depth == 0) {
+ return {
+ array : [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ],
+ string : 'String for key ' + tag + ' in leaf node'
+ };
+ } else {
+ return {
+ left: GeneratePayloadTree(depth - 1, tag),
+ right: GeneratePayloadTree(depth - 1, tag)
+ };
+ }
+}
+
+
+function GenerateKey() {
+ // The benchmark framework guarantees that Math.random is
+ // deterministic; see base.js.
+ return Math.random();
+}
+
+
+function InsertNewNode() {
+ // Insert new node with a unique key.
+ var key;
+ do {
+ key = GenerateKey();
+ } while (splayTree.find(key) != null);
+ var payload = GeneratePayloadTree(kSplayTreePayloadDepth, String(key));
+ splayTree.insert(key, payload);
+ return key;
+}
+
+
+
+function SplaySetup() {
+ splayTree = new SplayTree();
+ for (var i = 0; i < kSplayTreeSize; i++) InsertNewNode();
+}
+
+
+function SplayTearDown() {
+ // Allow the garbage collector to reclaim the memory
+ // used by the splay tree no matter how we exit the
+ // tear down function.
+ var keys = splayTree.exportKeys();
+ splayTree = null;
+
+ // Verify that the splay tree has the right size.
+ var length = keys.length;
+ if (length != kSplayTreeSize) {
+ throw new Error("Splay tree has wrong size");
+ }
+
+ // Verify that the splay tree has sorted, unique keys.
+ for (var i = 0; i < length - 1; i++) {
+ if (keys[i] >= keys[i + 1]) {
+ throw new Error("Splay tree not sorted");
+ }
+ }
+}
+
+
+function SplayRun() {
+ // Replace a few nodes in the splay tree.
+ for (var i = 0; i < kSplayTreeModifications; i++) {
+ var key = InsertNewNode();
+ var greatest = splayTree.findGreatestLessThan(key);
+ if (greatest == null) splayTree.remove(key);
+ else splayTree.remove(greatest.key);
+ }
+}
+
+
+/**
+ * Constructs a Splay tree. A splay tree is a self-balancing binary
+ * search tree with the additional property that recently accessed
+ * elements are quick to access again. It performs basic operations
+ * such as insertion, look-up and removal in O(log(n)) amortized time.
+ *
+ * @constructor
+ */
+function SplayTree() {
+};
+
+
+/**
+ * Pointer to the root node of the tree.
+ *
+ * @type {SplayTree.Node}
+ * @private
+ */
+SplayTree.prototype.root_ = null;
+
+
+/**
+ * @return {boolean} Whether the tree is empty.
+ */
+SplayTree.prototype.isEmpty = function() {
+ return !this.root_;
+};
+
+
+/**
+ * Inserts a node into the tree with the specified key and value if
+ * the tree does not already contain a node with the specified key. If
+ * the value is inserted, it becomes the root of the tree.
+ *
+ * @param {number} key Key to insert into the tree.
+ * @param {*} value Value to insert into the tree.
+ */
+SplayTree.prototype.insert = function(key, value) {
+ if (this.isEmpty()) {
+ this.root_ = new SplayTree.Node(key, value);
+ return;
+ }
+ // Splay on the key to move the last node on the search path for
+ // the key to the root of the tree.
+ this.splay_(key);
+ if (this.root_.key == key) {
+ return;
+ }
+ var node = new SplayTree.Node(key, value);
+ if (key > this.root_.key) {
+ node.left = this.root_;
+ node.right = this.root_.right;
+ this.root_.right = null;
+ } else {
+ node.right = this.root_;
+ node.left = this.root_.left;
+ this.root_.left = null;
+ }
+ this.root_ = node;
+};
+
+
+/**
+ * Removes a node with the specified key from the tree if the tree
+ * contains a node with this key. The removed node is returned. If the
+ * key is not found, an exception is thrown.
+ *
+ * @param {number} key Key to find and remove from the tree.
+ * @return {SplayTree.Node} The removed node.
+ */
+SplayTree.prototype.remove = function(key) {
+ if (this.isEmpty()) {
+ throw Error('Key not found: ' + key);
+ }
+ this.splay_(key);
+ if (this.root_.key != key) {
+ throw Error('Key not found: ' + key);
+ }
+ var removed = this.root_;
+ if (!this.root_.left) {
+ this.root_ = this.root_.right;
+ } else {
+ var right = this.root_.right;
+ this.root_ = this.root_.left;
+ // Splay to make sure that the new root has an empty right child.
+ this.splay_(key);
+ // Insert the original right child as the right child of the new
+ // root.
+ this.root_.right = right;
+ }
+ return removed;
+};
+
+
+/**
+ * Returns the node having the specified key or null if the tree doesn't contain
+ * a node with the specified key.
+ *
+ * @param {number} key Key to find in the tree.
+ * @return {SplayTree.Node} Node having the specified key.
+ */
+SplayTree.prototype.find = function(key) {
+ if (this.isEmpty()) {
+ return null;
+ }
+ this.splay_(key);
+ return this.root_.key == key ? this.root_ : null;
+};
+
+
+/**
+ * @return {SplayTree.Node} Node having the maximum key value.
+ */
+SplayTree.prototype.findMax = function(opt_startNode) {
+ if (this.isEmpty()) {
+ return null;
+ }
+ var current = opt_startNode || this.root_;
+ while (current.right) {
+ current = current.right;
+ }
+ return current;
+};
+
+
+/**
+ * @return {SplayTree.Node} Node having the maximum key value that
+ * is less than the specified key value.
+ */
+SplayTree.prototype.findGreatestLessThan = function(key) {
+ if (this.isEmpty()) {
+ return null;
+ }
+ // 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.
+ this.splay_(key);
+ // Now the result is either the root node or the greatest node in
+ // the left subtree.
+ if (this.root_.key < key) {
+ return this.root_;
+ } else if (this.root_.left) {
+ return this.findMax(this.root_.left);
+ } else {
+ return null;
+ }
+};
+
+
+/**
+ * @return {Array<*>} An array containing all the keys of tree's nodes.
+ */
+SplayTree.prototype.exportKeys = function() {
+ var result = [];
+ if (!this.isEmpty()) {
+ this.root_.traverse_(function(node) { result.push(node.key); });
+ }
+ return result;
+};
+
+
+/**
+ * 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. This is the simplified top-down splaying algorithm from:
+ * "Self-adjusting Binary Search Trees" by Sleator and Tarjan
+ *
+ * @param {number} key Key to splay the tree on.
+ * @private
+ */
+SplayTree.prototype.splay_ = function(key) {
+ if (this.isEmpty()) {
+ return;
+ }
+ // 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.
+ var dummy, left, right;
+ dummy = left = right = new SplayTree.Node(null, null);
+ var current = this.root_;
+ while (true) {
+ if (key < current.key) {
+ if (!current.left) {
+ break;
+ }
+ if (key < current.left.key) {
+ // Rotate right.
+ var tmp = current.left;
+ current.left = tmp.right;
+ tmp.right = current;
+ current = tmp;
+ if (!current.left) {
+ break;
+ }
+ }
+ // Link right.
+ right.left = current;
+ right = current;
+ current = current.left;
+ } else if (key > current.key) {
+ if (!current.right) {
+ break;
+ }
+ if (key > current.right.key) {
+ // Rotate left.
+ var tmp = current.right;
+ current.right = tmp.left;
+ tmp.left = current;
+ current = tmp;
+ if (!current.right) {
+ 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;
+ this.root_ = current;
+};
+
+
+/**
+ * Constructs a Splay tree node.
+ *
+ * @param {number} key Key.
+ * @param {*} value Value.
+ */
+SplayTree.Node = function(key, value) {
+ this.key = key;
+ this.value = value;
+};
+
+
+/**
+ * @type {SplayTree.Node}
+ */
+SplayTree.Node.prototype.left = null;
+
+
+/**
+ * @type {SplayTree.Node}
+ */
+SplayTree.Node.prototype.right = null;
+
+
+/**
+ * Performs an ordered traversal of the subtree starting at
+ * this SplayTree.Node.
+ *
+ * @param {function(SplayTree.Node)} f Visitor function.
+ * @private
+ */
+SplayTree.Node.prototype.traverse_ = function(f) {
+ var current = this;
+ while (current) {
+ var left = current.left;
+ if (left) left.traverse_(f);
+ f(current);
+ current = current.right;
+ }
+};
+
+SplaySetup();
+SplayRun();
+SplayTearDown();
projects / vuplus_webkit / blobdiff