// Copyright 2011 David Galles, University of San Francisco. All rights reserved. // // Redistribution and use in source and binary forms, with or without modification, are // permitted provided that the following conditions are met: // // 1. Redistributions of source code must retain the above copyright notice, this list of // conditions and the following disclaimer. // // 2. 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. // // THIS SOFTWARE IS PROVIDED BY ``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 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. // // The views and conclusions contained in the software and documentation are those of the // authors and should not be interpreted as representing official policies, either expressed // or implied, of the University of San Francisco var FIRST_PRINT_POS_X = 50; var PRINT_VERTICAL_GAP = 20; var PRINT_MAX = 990; var PRINT_HORIZONTAL_GAP = 50; var MIN_MAX_DEGREE = 3; var MAX_MAX_DEGREE = 7; var HEIGHT_DELTA = 50; var NODE_SPACING = 15; var STARTING_Y = 30; var WIDTH_PER_ELEM = 40; var NODE_HEIGHT = 20; var MESSAGE_X = 5; var MESSAGE_Y = 10; var LINK_COLOR = "#007700"; var HIGHLIGHT_CIRCLE_COLOR = "#007700"; var FOREGROUND_COLOR = "#007700"; var BACKGROUND_COLOR = "#EEFFEE"; var PRINT_COLOR = FOREGROUND_COLOR; function BPlusTree(am, w, h) { this.init(am, w, h); } BPlusTree.prototype = new Algorithm(); BPlusTree.prototype.varructor = BPlusTree; BPlusTree.superclass = Algorithm.prototype; BPlusTree.prototype.init = function(am, w, h) { BPlusTree.superclass.init.call(this, am, w, h); this.nextIndex = 0; this.preemptiveSplit = false this.starting_x = w / 2; this.addControls(); this.max_keys = 2; this.min_keys = 1; this.split_index = 1; this.max_degree = 3; this.messageID = this.nextIndex++; this.cmd("CreateLabel", this.messageID, "", MESSAGE_X, MESSAGE_Y, 0); this.moveLabel1ID = this.nextIndex++; this.moveLabel2ID = this.nextIndex++; animationManager.StartNewAnimation(this.commands); animationManager.skipForward(); animationManager.clearHistory(); this.commands = new Array(); this.first_print_pos_y = h - 3 * PRINT_VERTICAL_GAP; this.xPosOfNextLabel = 100; this.yPosOfNextLabel = 200; } BPlusTree.prototype.addControls = function() { this.controls = []; this.insertField = addControlToAlgorithmBar("Text", ""); this.insertField.onkeydown = this.returnSubmit(this.insertField, this.insertCallback.bind(this), 4); this.controls.push(this.insertField); this.insertButton = addControlToAlgorithmBar("Button", "添加"); this.insertButton.onclick = this.insertCallback.bind(this); this.controls.push(this.insertButton); this.deleteField = addControlToAlgorithmBar("Text", ""); this.deleteField.onkeydown = this.returnSubmit(this.deleteField, this.deleteCallback.bind(this), 4); this.controls.push(this.deleteField); this.deleteButton = addControlToAlgorithmBar("Button", "删除"); this.deleteButton.onclick = this.deleteCallback.bind(this); this.controls.push(this.deleteButton); this.findField = addControlToAlgorithmBar("Text", ""); this.findField.onkeydown = this.returnSubmit(this.findField, this.findCallback.bind(this), 4); this.controls.push(this.findField); this.findButton = addControlToAlgorithmBar("Button", "搜索"); this.findButton.onclick = this.findCallback.bind(this); this.controls.push(this.findButton); this.printButton = addControlToAlgorithmBar("Button", "打印"); this.printButton.onclick = this.printCallback.bind(this); this.controls.push(this.printButton); this.clearButton = addControlToAlgorithmBar("Button", "Clear"); this.clearButton.onclick = this.clearCallback.bind(this); this.controls.push(this.clearButton); var i; radioButtonNames = []; for (i = MIN_MAX_DEGREE; i <= MAX_MAX_DEGREE; i++) { radioButtonNames.push("Max. Degree = " + String(i)); } this.maxDegreeRadioButtons = addRadioButtonGroupToAlgorithmBar(radioButtonNames, "MaxDegree"); this.maxDegreeRadioButtons[0].checked = true; for(i = 0; i < this.maxDegreeRadioButtons.length; i++) { this.maxDegreeRadioButtons[i].onclick = this.maxDegreeChangedHandler.bind(this,i+MIN_MAX_DEGREE); } // this.premptiveSplitBox = addCheckboxToAlgorithmBar("Preemtive Split / Merge (Even max degree only)"); // this.premptiveSplitBox.onclick = this.premtiveSplitCallback.bind(this); // Other buttons ... } BPlusTree.prototype.reset = function() { this.nextIndex = 3; this.max_degree = 3; this.max_keys = 2; this.min_keys = 1; this.split_index = 1; // NOTE: The order of these last two this.commands matters! this.treeRoot = null; this.ignoreInputs = true; // maxDegreeButtonArray[this.max_degree].selected = true; this.ignoreInputs = false; } BPlusTree.prototype.enableUI = function(event) { var i; for (i = 0; i < this.controls.length; i++) { this.controls[i].disabled = false; } for (i = 0; i < this.maxDegreeRadioButtons.length; i++) { this.maxDegreeRadioButtons[i].disabled = false; } } BPlusTree.prototype.disableUI = function(event) { for (var i = 0; i < this.controls.length; i++) { this.controls[i].disabled = true; } for (i = 0; i < this.maxDegreeRadioButtons.length; i++) { this.maxDegreeRadioButtons[i].disabled = true; } } //TODO: Fix me! BPlusTree.prototype.maxDegreeChangedHandler = function(newMaxDegree, event) { if (this.max_degree != newMaxDegree) { this.implementAction(this.changeDegree.bind(this), newMaxDegree); } } BPlusTree.prototype.insertCallback = function(event) { var insertedValue; insertedValue = this.normalizeNumber(this.insertField.value, 4); if (insertedValue != "") { this.insertField.value = ""; this.implementAction(this.insertElement.bind(this),insertedValue); } } BPlusTree.prototype.deleteCallback = function(event) { var deletedValue = this.deleteField.value; if (deletedValue != "") { deletedValue = this.normalizeNumber(this.deleteField.value, 4); this.deleteField.value = ""; this.implementAction(this.deleteElement.bind(this),deletedValue); } } BPlusTree.prototype.clearCallback = function(event) { this.implementAction(this.clearTree.bind(this), ""); } BPlusTree.prototype.premtiveSplitCallback = function(event) { // if (this.preemptiveSplit != this.premptiveSplitBox.checked) // { // this.implementAction(this.changePreemtiveSplit.bind(this), this.premptiveSplitBox.checked); // } } BPlusTree.prototype.changePreemtiveSplit = function(newValue) { // this.commands = new Array(); // this.cmd("Step"); // this.preemptiveSplit = newValue; // if (this.premptiveSplitBox.checked != this.preemptiveSplit) // { // this.premptiveSplitBox.checked = this.preemptiveSplit; // } // return this.commands; } BPlusTree.prototype.printCallback = function(event) { this.implementAction(this.printTree.bind(this),""); } BPlusTree.prototype.printTree = function(unused) { this.commands = new Array(); this.cmd("SetText", this.messageID, "Printing tree"); var firstLabel = this.nextIndex; if (this.treeRoot != null) { this.xPosOfNextLabel = FIRST_PRINT_POS_X; this.yPosOfNextLabel = this.first_print_pos_y; var tmp = this.treeRoot; this.cmd("SetHighlight", tmp.graphicID, 1); this.cmd("Step"); while (!tmp.isLeaf) { this.cmd("SetEdgeHighlight", tmp.graphicID, tmp.children[0].graphicID, 1); this.cmd("Step"); this.cmd("SetHighlight", tmp.graphicID, 0); this.cmd("SetHighlight", tmp.children[0].graphicID, 1); this.cmd("SetEdgeHighlight", tmp.graphicID, tmp.children[0].graphicID, 0); this.cmd("Step"); tmp = tmp.children[0]; } while (tmp!= null) { this.cmd("SetHighlight", tmp.graphicID, 1); for (i = 0; i < tmp.numKeys; i++) { var nextLabelID = this.nextIndex++; this.cmd("CreateLabel", nextLabelID, tmp.keys[i], this.getLabelX(tmp, i), tmp.y); this.cmd("SetForegroundColor", nextLabelID, PRINT_COLOR); this.cmd("Move", nextLabelID, this.xPosOfNextLabel, this.yPosOfNextLabel); this.cmd("Step"); this.xPosOfNextLabel += PRINT_HORIZONTAL_GAP; if (this.xPosOfNextLabel > PRINT_MAX) { this.xPosOfNextLabel = FIRST_PRINT_POS_X; this.yPosOfNextLabel += PRINT_VERTICAL_GAP; } } if (tmp.next != null) { this.cmd("SetEdgeHighlight", tmp.graphicID, tmp.next.graphicID, 1); this.cmd("Step"); this.cmd("SetEdgeHighlight", tmp.graphicID, tmp.next.graphicID, 0); } this.cmd("SetHighlight", tmp.graphicID, 0); tmp = tmp.next; } this.cmd("Step"); for (var i = firstLabel; i < this.nextIndex; i++) { this.cmd("Delete", i); } this.nextIndex = firstLabel; } this.cmd("SetText", this.messageID, ""); return this.commands; } BPlusTree.prototype.clearTree = function(ignored) { this.commands = new Array(); this.deleteTree(this.treeRoot); this.treeRoot = null; this.nextIndex = 3; return this.commands; } BPlusTree.prototype.deleteTree = function(tree) { if (tree != null) { if (!tree.isLeaf) { for (var i = 0; i <= tree.numKeys; i++) { this.cmd("Disconnect", tree.graphicID, tree.children[i].graphicID); this.deleteTree(tree.children[i]); tree.children[i] == null; } } this.cmd("Delete", tree.graphicID); } } BPlusTree.prototype.changeDegree = function(degree) { this.commands = new Array(); this.deleteTree(this.treeRoot); this.treeRoot = null; this.nextIndex = 3; var newDegree = degree; this.ignoreInputs = true; //TODO: Check me! this.maxDegreeRadioButtons[newDegree - MIN_MAX_DEGREE].checked = true; this.ignoreInputs = false; this.max_degree = newDegree; this.max_keys = newDegree - 1; this.min_keys = Math.floor((newDegree + 1) / 2) - 1; this.split_index = Math.floor((newDegree) / 2); if (this.commands.length == 0) { this.cmd("Step"); } if (newDegree % 2 != 0 && this.preemptiveSplit) { this.preemptiveSplit = false; this.premptiveSplitBox.checked = false; } return this.commands; } BPlusTree.prototype.findCallback = function(event) { var findValue; findValue = this.normalizeNumber(this.findField.value, 4); this.findField.value = ""; this.implementAction(this.findElement.bind(this),findValue); } BPlusTree.prototype.findElement = function(findValue) { this.commands = new Array(); this.cmd("SetText", this.messageID, "Finding " + findValue); this.findInTree(this.treeRoot, findValue); return this.commands; } BPlusTree.prototype.findInTree = function(tree, val) { if (tree != null) { this.cmd("SetHighlight", tree.graphicID, 1); this.cmd("Step"); var i; for (i = 0; i < tree.numKeys && tree.keys[i] < val; i++); if (i == tree.numKeys) { if (!tree.isLeaf) { this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 1); this.cmd("Step"); this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 0); this.findInTree(tree.children[tree.numKeys], val); } else { this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetText", this.messageID, "Element " + val + " is not in the tree"); } } else if (tree.keys[i] > val) { if (!tree.isLeaf) { this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 1); this.cmd("Step"); this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 0); this.findInTree(tree.children[i], val); } else { this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetText", this.messageID, "Element " + val + " is not in the tree"); } } else { if (tree.isLeaf) { this.cmd("SetTextColor", tree.graphicID, "#FF0000", i); this.cmd("SetText", this.messageID, "Element " + val + " found"); this.cmd("Step"); this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i); this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("Step"); } else { this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i+1].graphicID, 1); this.cmd("Step"); this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i+1].graphicID, 0); this.findInTree(tree.children[i+1], val); } } } else { this.cmd("SetText", this.messageID, "Element " + val + " is not in the tree"); } } BPlusTree.prototype.insertElement = function(insertedValue) { this.commands = new Array(); this.cmd("SetText", this.messageID, "Inserting " + insertedValue); this.cmd("Step"); if (this.treeRoot == null) { this.treeRoot = new BTreeNode(this.nextIndex++, this.starting_x, STARTING_Y); this.cmd("CreateBTreeNode",this.treeRoot.graphicID, WIDTH_PER_ELEM, NODE_HEIGHT, 1, this.starting_x, STARTING_Y, BACKGROUND_COLOR, FOREGROUND_COLOR); this.treeRoot.keys[0] = insertedValue; this.cmd("SetText", this.treeRoot.graphicID, insertedValue, 0); } else { this.insert(this.treeRoot, insertedValue); if (!this.treeRoot.isLeaf) { this.resizeTree(); } } this.cmd("SetText", this.messageID, ""); return this.commands; } BPlusTree.prototype.insert = function(tree, insertValue) { this.cmd("SetHighlight", tree.graphicID, 1); this.cmd("Step"); if (tree.isLeaf) { this.cmd("SetText", this.messageID, "Inserting " + insertValue + ". Inserting into a leaf"); tree.numKeys++; this.cmd("SetNumElements", tree.graphicID, tree.numKeys); var insertIndex = tree.numKeys - 1; while (insertIndex > 0 && tree.keys[insertIndex - 1] > insertValue) { tree.keys[insertIndex] = tree.keys[insertIndex - 1]; this.cmd("SetText", tree.graphicID, tree.keys[insertIndex], insertIndex); insertIndex--; } tree.keys[insertIndex] = insertValue; this.cmd("SetText", tree.graphicID, tree.keys[insertIndex], insertIndex); this.cmd("SetHighlight", tree.graphicID, 0); if (tree.next != null) { this.cmd("Disconnect", tree.graphicID, tree.next.graphicID); this.cmd("Connect", tree.graphicID, tree.next.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label tree.numKeys); } this.resizeTree(); this.insertRepair(tree); } else { var findIndex = 0; while (findIndex < tree.numKeys && tree.keys[findIndex] < insertValue) { findIndex++; } this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[findIndex].graphicID, 1); this.cmd("Step"); this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[findIndex].graphicID, 0); this.cmd("SetHighlight", tree.graphicID, 0); this.insert(tree.children[findIndex], insertValue); } } BPlusTree.prototype.insertRepair = function(tree) { if (tree.numKeys <= this.max_keys) { return; } else if (tree.parent == null) { this.treeRoot = this.split(tree); return; } else { var newNode = this.split(tree); this.insertRepair(newNode); } } BPlusTree.prototype.split = function(tree) { this.cmd("SetText", this.messageID, "Node now contains too many keys. Splittig ..."); this.cmd("SetHighlight", tree.graphicID, 1); this.cmd("Step"); this.cmd("SetHighlight", tree.graphicID, 0); var rightNode = new BTreeNode(this.nextIndex++, tree.x + 100, tree.y); var risingNode = tree.keys[this.split_index]; var i; var parentIndex if (tree.parent != null) { var currentParent = tree.parent; for (parentIndex = 0; parentIndex < currentParent.numKeys + 1 && currentParent.children[parentIndex] != tree; parentIndex++); if (parentIndex == currentParent.numKeys + 1) { throw new Error("Couldn't find which child we were!"); } this.cmd("SetNumElements", currentParent.graphicID, currentParent.numKeys + 1); for (i = currentParent.numKeys; i > parentIndex; i--) { currentParent.children[i+1] = currentParent.children[i]; this.cmd("Disconnect", currentParent.graphicID, currentParent.children[i].graphicID); this.cmd("Connect", currentParent.graphicID, currentParent.children[i].graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label i+1); currentParent.keys[i] = currentParent.keys[i-1]; this.cmd("SetText", currentParent.graphicID, currentParent.keys[i] ,i); } currentParent.numKeys++; currentParent.keys[parentIndex] = risingNode; this.cmd("SetText", currentParent.graphicID, "", parentIndex); this.cmd("CreateLabel", this.moveLabel1ID, risingNode, this.getLabelX(tree, this.split_index), tree.y) this.cmd("Move", this.moveLabel1ID, this.getLabelX(currentParent, parentIndex), currentParent.y) currentParent.children[parentIndex+1] = rightNode; rightNode.parent = currentParent; } var rightSplit; if (tree.isLeaf) { rightSplit = this.split_index; rightNode.next = tree.next; tree.next = rightNode; } else { rightSplit = this.split_index + 1; } rightNode.numKeys = tree.numKeys - rightSplit; this.cmd("CreateBTreeNode",rightNode.graphicID, WIDTH_PER_ELEM, NODE_HEIGHT, tree.numKeys -rightSplit, tree.x, tree.y, BACKGROUND_COLOR, FOREGROUND_COLOR); if (tree.isLeaf) { if (rightNode.next != null) { this.cmd("Disconnect", tree.graphicID, rightNode.next.graphicID); this.cmd("Connect", rightNode.graphicID, rightNode.next.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label rightNode.numKeys); } this.cmd("Connect", tree.graphicID, rightNode.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label this.split_index); } for (var i = rightSplit; i < tree.numKeys + 1; i++) { rightNode.children[i - rightSplit] = tree.children[i]; if (tree.children[i] != null) { rightNode.isLeaf = false; this.cmd("Disconnect", tree.graphicID, tree.children[i].graphicID); this.cmd("Connect", rightNode.graphicID, rightNode.children[i - rightSplit].graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label i - rightSplit); if (tree.children[i] != null) { tree.children[i].parent = rightNode; } tree.children[i] = null; } } for (i =rightSplit; i < tree.numKeys; i++) { rightNode.keys[i - rightSplit] = tree.keys[i]; this.cmd("SetText", rightNode.graphicID, rightNode.keys[i -rightSplit], i - rightSplit); } var leftNode = tree; leftNode.numKeys = this.split_index; // TO MAKE UNDO WORK -- CAN REMOVE LATER VV for (i = this.split_index; i < tree.numKeys; i++) { this.cmd("SetText", tree.graphicID, "", i); } // TO MAKE UNDO WORK -- CAN REMOVE LATER ^^ this.cmd("SetNumElements", tree.graphicID, this.split_index); if (tree.parent != null) { this.cmd("Connect", currentParent.graphicID, rightNode.graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label parentIndex + 1); this.resizeTree(); this.cmd("Step") this.cmd("Delete", this.moveLabel1ID); this.cmd("SetText", currentParent.graphicID, risingNode, parentIndex); return tree.parent; } else // if (tree.parent == null) { this.treeRoot = new BTreeNode(this.nextIndex++, this.starting_x, STARTING_Y); this.cmd("CreateBTreeNode",this.treeRoot.graphicID, WIDTH_PER_ELEM, NODE_HEIGHT, 1, this.starting_x, STARTING_Y,BACKGROUND_COLOR, FOREGROUND_COLOR); this.treeRoot.keys[0] = risingNode; this.cmd("SetText", this.treeRoot.graphicID, risingNode, 0); this.treeRoot.children[0] = leftNode; this.treeRoot.children[1] = rightNode; leftNode.parent = this.treeRoot; rightNode.parent = this.treeRoot; this.cmd("Connect", this.treeRoot.graphicID, leftNode.graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label 0); // Connection Point this.cmd("Connect", this.treeRoot.graphicID, rightNode.graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label 1); // Connection Point this.treeRoot.isLeaf = false; return this.treeRoot; } } BPlusTree.prototype.deleteElement = function(deletedValue) { this.commands = new Array(); this.cmd("SetText", 0, "正在刪除 "+deletedValue); this.cmd("Step"); this.cmd("SetText", 0, ""); this.cmd("SetText", 0, ""); this.doDelete(this.treeRoot, deletedValue); if (this.treeRoot.numKeys == 0) { this.cmd("Delete", this.treeRoot.graphicID); this.treeRoot = this.treeRoot.children[0]; this.treeRoot.parent = null; this.resizeTree(); } return this.commands; } BPlusTree.prototype.doDelete = function(tree, val) { if (tree != null) { this.cmd("SetHighlight", tree.graphicID, 1); this.cmd("Step"); var i; for (i = 0; i < tree.numKeys && tree.keys[i] < val; i++); if (i == tree.numKeys) { if (!tree.isLeaf) { this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 1); this.cmd("Step"); this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[tree.numKeys].graphicID, 0); this.doDelete(tree.children[tree.numKeys], val); } else { this.cmd("SetHighlight", tree.graphicID, 0); } } else if (!tree.isLeaf && tree.keys[i] == val) { this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i+1].graphicID, 1); this.cmd("Step"); this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i+1].graphicID, 0); this.doDelete(tree.children[i+1], val); } else if (!tree.isLeaf) { this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 1); this.cmd("Step"); this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetEdgeHighlight", tree.graphicID, tree.children[i].graphicID, 0); this.doDelete(tree.children[i], val); } else if (tree.isLeaf && tree.keys[i] == val) { this.cmd("SetTextColor", tree.graphicID, 0xFF0000, i); this.cmd("Step"); this.cmd("SetTextColor", tree.graphicID, FOREGROUND_COLOR, i); for (var j = i; j < tree.numKeys - 1; j++) { tree.keys[j] = tree.keys[j+1]; this.cmd("SetText", tree.graphicID, tree.keys[j], j); } tree.numKeys--; this.cmd("SetText", tree.graphicID, "", tree.numKeys); this.cmd("SetNumElements", tree.graphicID, tree.numKeys); this.cmd("SetHighlight", tree.graphicID, 0); if (tree.next != null) { this.cmd("Disconnect", tree.graphicID, tree.next.graphicID); this.cmd("Connect", tree.graphicID, tree.next.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label tree.numKeys); } // Bit of a hack -- if we remove the smallest element in a leaf, then find the *next* smallest element // (somewhat tricky if the leaf is now empty!), go up our parent stack, and fix index keys if (i == 0 && tree.parent != null) { var nextSmallest = ""; var parentNode = tree.parent; var parentIndex; for (parentIndex = 0; parentNode.children[parentIndex] != tree; parentIndex++); if (tree.numKeys == 0) { if (parentIndex == parentNode.numKeys) { nextSmallest == ""; } else { nextSmallest = parentNode.children[parentIndex+1].keys[0]; } } else { nextSmallest = tree.keys[0]; } while (parentNode != null) { if (parentIndex > 0 && parentNode.keys[parentIndex - 1] == val) { parentNode.keys[parentIndex - 1] = nextSmallest; this.cmd("SetText", parentNode.graphicID, parentNode.keys[parentIndex - 1], parentIndex - 1); } var grandParent = parentNode.parent; for (parentIndex = 0; grandParent != null && grandParent.children[parentIndex] != parentNode; parentIndex++); parentNode = grandParent; } } this.repairAfterDelete(tree); } else { this.cmd("SetHighlight", tree.graphicID, 0); } } } BPlusTree.prototype.mergeRight = function(tree) { this.cmd("SetText", this.messageID, "Merging node"); var parentNode = tree.parent; var parentIndex = 0; for (parentIndex = 0; parentNode.children[parentIndex] != tree; parentIndex++); var rightSib = parentNode.children[parentIndex+1]; this.cmd("SetHighlight", tree.graphicID, 1); this.cmd("SetHighlight", parentNode.graphicID, 1); this.cmd("SetHighlight", rightSib.graphicID, 1); this.cmd("Step"); if (tree.isLeaf) { this.cmd("SetNumElements", tree.graphicID, tree.numKeys + rightSib.numKeys); } else { this.cmd("SetNumElements", tree.graphicID, tree.numKeys + rightSib.numKeys + 1); this.cmd("SetText", tree.graphicID, "", tree.numKeys); this.cmd("CreateLabel", this.moveLabel1ID, parentNode.keys[parentIndex], this.getLabelX(parentNode, parentIndex), parentNode.y); tree.keys[tree.numKeys] = parentNode.keys[parentIndex]; } tree.x = (tree.x + rightSib.x) / 2 this.cmd("SetPosition", tree.graphicID, tree.x, tree.y); var fromParentIndex = tree.numKeys; for (var i = 0; i < rightSib.numKeys; i++) { var insertIndex = tree.numKeys + 1 + i; if (tree.isLeaf) { insertIndex -= 1; } tree.keys[insertIndex] = rightSib.keys[i]; this.cmd("SetText", tree.graphicID, tree.keys[insertIndex], insertIndex); this.cmd("SetText", rightSib.graphicID, "", i); } if (!tree.isLeaf) { for (i = 0; i <= rightSib.numKeys; i++) { this.cmd("Disconnect", rightSib.graphicID, rightSib.children[i].graphicID); tree.children[tree.numKeys + 1 + i] = rightSib.children[i]; tree.children[tree.numKeys + 1 + i].parent = tree; this.cmd("Connect", tree.graphicID, tree.children[tree.numKeys + 1 + i].graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label tree.numKeys + 1 + i); } tree.numKeys = tree.numKeys + rightSib.numKeys + 1; } else { tree.numKeys = tree.numKeys + rightSib.numKeys; tree.next = rightSib.next; if (rightSib.next != null) { this.cmd("Connect", tree.graphicID, tree.next.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label tree.numKeys); } } this.cmd("Disconnect", parentNode.graphicID, rightSib.graphicID); for (i = parentIndex+1; i < parentNode.numKeys; i++) { this.cmd("Disconnect", parentNode.graphicID, parentNode.children[i+1].graphicID); parentNode.children[i] = parentNode.children[i+1]; this.cmd("Connect", parentNode.graphicID, parentNode.children[i].graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label i); parentNode.keys[i-1] = parentNode.keys[i]; this.cmd("SetText", parentNode.graphicID, parentNode.keys[i-1], i-1); } this.cmd("SetText", parentNode.graphicID, "", parentNode.numKeys - 1); parentNode.numKeys--; this.cmd("SetNumElements", parentNode.graphicID, parentNode.numKeys); this.cmd("SetHighlight", tree.graphicID, 0); this.cmd("SetHighlight", parentNode.graphicID, 0); this.cmd("SetHighlight", rightSib.graphicID, 0); this.cmd("Delete", rightSib.graphicID); if (!tree.isLeaf) { this.cmd("Move", this.moveLabel1ID, this.getLabelX(tree, fromParentIndex), tree.y); this.cmd("Step"); this.cmd("Delete", this.moveLabel1ID); this.cmd("SetText", tree.graphicID, tree.keys[fromParentIndex], fromParentIndex); } // this.resizeTree(); this.cmd("SetText", this.messageID, ""); return tree; } BPlusTree.prototype.stealFromRight = function(tree, parentIndex) { // Steal from right sibling var parentNode = tree.parent; this.cmd("SetNumElements", tree.graphicID, tree.numKeys+1); this.cmd("SetText", this.messageID, "Stealing from right sibling"); var rightSib = parentNode.children[parentIndex + 1]; tree.numKeys++; this.cmd("SetNumElements", tree.graphicID, tree.numKeys); if (tree.isLeaf) { this.cmd("Disconnect", tree.graphicID, tree.next.graphicID); this.cmd("Connect", tree.graphicID, tree.next.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label tree.numKeys); } this.cmd("SetText", tree.graphicID, "", tree.numKeys - 1); this.cmd("SetText", parentNode.graphicID, "", parentIndex); this.cmd("SetText", rightSib.graphicID, "", 0); if (tree.isLeaf) { this.cmd("CreateLabel", this.moveLabel1ID, rightSib.keys[1], this.getLabelX(rightSib, 1), rightSib.y) this.cmd("CreateLabel", this.moveLabel2ID, rightSib.keys[0], this.getLabelX(rightSib, 0), rightSib.y) tree.keys[tree.numKeys - 1] = rightSib.keys[0]; parentNode.keys[parentIndex] = rightSib.keys[1]; } else { this.cmd("CreateLabel", this.moveLabel1ID, rightSib.keys[0], this.getLabelX(rightSib, 0), rightSib.y) this.cmd("CreateLabel", this.moveLabel2ID, parentNode.keys[parentIndex], this.getLabelX(parentNode, parentIndex), parentNode.y) tree.keys[tree.numKeys - 1] = parentNode.keys[parentIndex]; parentNode.keys[parentIndex] = rightSib.keys[0]; } this.cmd("Move", this.moveLabel1ID, this.getLabelX(parentNode, parentIndex), parentNode.y); this.cmd("Move", this.moveLabel2ID, this.getLabelX(tree, tree.numKeys - 1), tree.y); this.cmd("Step") this.cmd("Delete", this.moveLabel1ID); this.cmd("Delete", this.moveLabel2ID); this.cmd("SetText", tree.graphicID, tree.keys[tree.numKeys - 1], tree.numKeys - 1); this.cmd("SetText", parentNode.graphicID, parentNode.keys[parentIndex], parentIndex); if (!tree.isLeaf) { tree.children[tree.numKeys] = rightSib.children[0]; tree.children[tree.numKeys].parent = tree; this.cmd("Disconnect", rightSib.graphicID, rightSib.children[0].graphicID); this.cmd("Connect", tree.graphicID, tree.children[tree.numKeys].graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label tree.numKeys); // TODO::CHECKME! for (var i = 1; i < rightSib.numKeys + 1; i++) { this.cmd("Disconnect", rightSib.graphicID, rightSib.children[i].graphicID); rightSib.children[i-1] = rightSib.children[i]; this.cmd("Connect", rightSib.graphicID, rightSib.children[i-1].graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label i-1); } } for (i = 1; i < rightSib.numKeys; i++) { rightSib.keys[i-1] = rightSib.keys[i]; this.cmd("SetText", rightSib.graphicID, rightSib.keys[i-1], i-1); } this.cmd("SetText", rightSib.graphicID, "", rightSib.numKeys-1); rightSib.numKeys--; this.cmd("SetNumElements", rightSib.graphicID, rightSib.numKeys); this.resizeTree(); this.cmd("SetText", this.messageID, ""); if (tree.isLeaf) { if (rightSib.next != null) { this.cmd("Disconnect", rightSib.graphicID, rightSib.next.graphicID); this.cmd("Connect", rightSib.graphicID, rightSib.next.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label rightSib.numKeys); } } return tree; } BPlusTree.prototype.stealFromLeft = function(tree, parentIndex) { var parentNode = tree.parent; // Steal from left sibling tree.numKeys++; this.cmd("SetNumElements", tree.graphicID, tree.numKeys); if (tree.isLeaf && tree.next != null) { this.cmd("Disconnect", tree.graphicID, tree.next.graphicID); this.cmd("Connect", tree.graphicID, tree.next.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label tree.numKeys); } this.cmd("SetText", this.messageID, "Node has too few keys. Stealing from left sibling."); for (i = tree.numKeys - 1; i > 0; i--) { tree.keys[i] = tree.keys[i-1]; this.cmd("SetText", tree.graphicID, tree.keys[i], i); } var leftSib = parentNode.children[parentIndex -1]; this.cmd("SetText", tree.graphicID, "", 0); this.cmd("SetText", parentNode.graphicID, "", parentIndex - 1); this.cmd("SetText", leftSib.graphicID, "", leftSib.numKeys - 1); if (tree.isLeaf) { this.cmd("CreateLabel", this.moveLabel1ID, leftSib.keys[leftSib.numKeys - 1], this.getLabelX(leftSib, leftSib.numKeys - 1), leftSib.y) this.cmd("CreateLabel", this.moveLabel2ID,leftSib.keys[leftSib.numKeys - 1], this.getLabelX(leftSib, leftSib.numKeys - 1), leftSib.y) tree.keys[0] = leftSib.keys[leftSib.numKeys - 1]; parentNode.keys[parentIndex-1] = leftSib.keys[leftSib.numKeys - 1]; } else { this.cmd("CreateLabel", this.moveLabel1ID, leftSib.keys[leftSib.numKeys - 1], this.getLabelX(leftSib, leftSib.numKeys - 1), leftSib.y) this.cmd("CreateLabel", this.moveLabel2ID, parentNode.keys[parentIndex - 1], this.getLabelX(parentNode, parentIndex - 1), parentNode.y) tree.keys[0] = parentNode.keys[parentIndex - 1]; parentNode.keys[parentIndex-1] = leftSib.keys[leftSib.numKeys - 1]; } this.cmd("Move", this.moveLabel1ID, this.getLabelX(parentNode, parentIndex - 1), parentNode.y); this.cmd("Move", this.moveLabel2ID, this.getLabelX(tree, 0), tree.y); this.cmd("Step") this.cmd("Delete", this.moveLabel1ID); this.cmd("Delete", this.moveLabel2ID); if (!tree.isLeaf) { for (var i = tree.numKeys; i > 0; i--) { this.cmd("Disconnect", tree.graphicID, tree.children[i-1].graphicID); tree.children[i] =tree.children[i-1]; this.cmd("Connect", tree.graphicID, tree.children[i].graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label i); } tree.children[0] = leftSib.children[leftSib.numKeys]; this.cmd("Disconnect", leftSib.graphicID, leftSib.children[leftSib.numKeys].graphicID); this.cmd("Connect", tree.graphicID, tree.children[0].graphicID, FOREGROUND_COLOR, 0, // Curve 0, // Directed "", // Label 0); leftSib.children[leftSib.numKeys] = null; tree.children[0].parent = tree; } this.cmd("SetText", tree.graphicID, tree.keys[0], 0); this.cmd("SetText", parentNode.graphicID, parentNode.keys[parentIndex - 1], parentIndex - 1); this.cmd("SetText", leftSib.graphicID,"", leftSib.numKeys - 1); leftSib.numKeys--; this.cmd("SetNumElements", leftSib.graphicID, leftSib.numKeys); this.resizeTree(); this.cmd("SetText", this.messageID, ""); if (tree.isLeaf) { this.cmd("Disconnect", leftSib.graphicID, tree.graphicID); this.cmd("Connect", leftSib.graphicID, tree.graphicID, FOREGROUND_COLOR, 0, // Curve 1, // Directed "", // Label leftSib.numKeys); } return tree; } BPlusTree.prototype.repairAfterDelete = function(tree) { if (tree.numKeys < this.min_keys) { if (tree.parent == null) { if (tree.numKeys == 0) { this.cmd("Delete", tree.graphicID); this.treeRoot = tree.children[0]; if (this.treeRoot != null) this.treeRoot.parent = null; this.resizeTree(); } } else { var parentNode = tree.parent; for (var parentIndex = 0; parentNode.children[parentIndex] != tree; parentIndex++); if (parentIndex > 0 && parentNode.children[parentIndex - 1].numKeys > this.min_keys) { this.stealFromLeft(tree, parentIndex); } else if (parentIndex < parentNode.numKeys && parentNode.children[parentIndex + 1].numKeys > this.min_keys) { this.stealFromRight(tree,parentIndex); } else if (parentIndex == 0) { // Merge with right sibling var nextNode = this.mergeRight(tree); this.repairAfterDelete(nextNode.parent); } else { // Merge with left sibling nextNode = this.mergeRight(parentNode.children[parentIndex-1]); this.repairAfterDelete(nextNode.parent); } } } else if (tree.parent != null) { } } BPlusTree.prototype.getLabelX = function(tree, index) { return tree.x - WIDTH_PER_ELEM * tree.numKeys / 2 + WIDTH_PER_ELEM / 2 + index * WIDTH_PER_ELEM; } BPlusTree.prototype.resizeTree = function() { this.resizeWidths(this.treeRoot); this.setNewPositions(this.treeRoot, this.starting_x, STARTING_Y); this.animateNewPositions(this.treeRoot); } BPlusTree.prototype.setNewPositions = function(tree, xPosition, yPosition) { if (tree != null) { tree.y = yPosition; tree.x = xPosition; if (!tree.isLeaf) { var leftEdge = xPosition - tree.width / 2; var priorWidth = 0; for (var i = 0; i < tree.numKeys+1; i++) { this.setNewPositions(tree.children[i], leftEdge + priorWidth + tree.widths[i] / 2, yPosition+HEIGHT_DELTA); priorWidth += tree.widths[i]; } } } } BPlusTree.prototype.animateNewPositions = function(tree) { if (tree == null) { return; } var i; for (i = 0; i < tree.numKeys + 1; i++) { this.animateNewPositions(tree.children[i]); } this.cmd("Move", tree.graphicID, tree.x, tree.y); } BPlusTree.prototype.resizeWidths = function(tree) { if (tree == null) { return 0; } if (tree.isLeaf) { for (var i = 0; i < tree.numKeys + 1; i++) { tree.widths[i] = 0; } tree.width = tree.numKeys * WIDTH_PER_ELEM + NODE_SPACING; return tree.width; } else { var treeWidth = 0; for (i = 0; i < tree.numKeys+1; i++) { tree.widths[i] = this.resizeWidths(tree.children[i]); treeWidth = treeWidth + tree.widths[i]; } treeWidth = Math.max(treeWidth, tree.numKeys * WIDTH_PER_ELEM + NODE_SPACING); tree.width = treeWidth; return treeWidth; } } function BTreeNode(id, initialX, initialY) { this.widths = []; this.keys = []; this.children = []; this.x = initialX; this.y = initialY; this.graphicID = id; this.numKeys = 1; this.isLeaf = true; this.parent = null; this.leftWidth = 0; this.rightWidth = 0; // Could use children for next pointer, but I got lazy ... this.next = null; } var currentAlg; function init() { var animManag = initCanvas(); currentAlg = new BPlusTree(animManag, canvas.width, canvas.height); }