/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.uima.internal.util.rb_trees;
import java.util.Stack;
import org.apache.uima.internal.util.IntStack;
import org.apache.uima.internal.util.IntVector;
/**
* Integer Red-Black Tree node. Not for public use. Use the interface in IntRedBlackTree instead.
* This should probably be an internal class to IntRedBlackTree, but it's easier to read in a
* seperate file. See comments in IntRedBlackTree.
*
*
*/
class IntRBTNode {
// The colors.
private static final boolean RED = true;
private static final boolean BLACK = false;
private int key; // The key of the node.
private boolean color; // The color of the node.
// A pointer to the parent node. This will be null if this is the
// root of a tree.
private IntRBTNode parent;
// The following variables are package private so they can be
// accessed from IntRedBlackTree.
IntRBTNode left; // The left daughter.
IntRBTNode right; // The right daughter.
int element; // The element contained in the node.
// For the debugging print functions.
private static final int indentInc = 2;
/**
* The real constructor, used only internally.
*/
private IntRBTNode(int key, boolean color, IntRBTNode parent, IntRBTNode left, IntRBTNode right,
int element) {
this.key = key;
this.color = color;
this.parent = parent;
this.left = left;
this.right = right;
this.element = element;
}
/**
* The standard constructor as used by IntRedBlackTree.
*
* @param key
* The key to be inserted.
* @param element
* The value to be inserted.
*/
IntRBTNode(int key, int element) {
// The default color is completely arbitrary.
this(key, BLACK, null, null, null, element);
}
/**
* Find a node with a certain key. Returns null if no such node exists.
*/
static final IntRBTNode find(IntRBTNode x, int key) {
while (x != null && x.key != key) {
if (key < x.key) {
x = x.left;
} else {
x = x.right;
}
}
return x;
}
/** Find the successor node to this. */
final IntRBTNode successor() {
IntRBTNode x = this;
// If this has a right daughter, then the successor will be the
// leftmost daughter of this.right, if it exists, and x.right,
// else.
if (x.right != null) {
x = x.right;
while (x.left != null) {
x = x.left;
}
return x;
}
// If this does not have a right daughter, we need to move up in
// the tree until we hit a node we're the left daughter of. That
// will be the successor.
IntRBTNode y = x.parent;
while (y != null && x == y.right) {
x = y;
y = x.parent;
}
return y;
}
/** Insert a node into a tree. See CLR. */
static final boolean insert(IntRedBlackTree tree, IntRBTNode x) {
if (!treeInsert(tree, x)) {
// A node with the same key as x already existed in the tree, so
// there is nothing left to do.
return false;
}
IntRBTNode y;
x.color = RED;
while (x != tree.root && x.parent.color == RED) {
if (x.parent == x.parent.parent.left) {
y = x.parent.parent.right;
if (colorOf(y) == RED) {
x.parent.color = BLACK;
setColor(y, BLACK);
x.parent.parent.color = RED;
x = x.parent.parent;
} else {
if (x == x.parent.right) {
x = x.parent;
x.leftRotate(tree);
}
x.parent.color = BLACK;
x.parent.parent.color = RED;
x.parent.parent.rightRotate(tree);
}
} else {
y = x.parent.parent.left;
if (colorOf(y) == RED) {
x.parent.color = BLACK;
setColor(y, BLACK);
x.parent.parent.color = RED;
x = x.parent.parent;
} else {
if (x == x.parent.left) {
x = x.parent;
x.rightRotate(tree);
}
x.parent.color = BLACK;
x.parent.parent.color = RED;
x.parent.parent.leftRotate(tree);
}
}
}
tree.root.color = BLACK;
return true;
}
/** Auxiliary function for insert(). See CLR. */
private static final boolean treeInsert(IntRedBlackTree tree, IntRBTNode z) {
IntRBTNode y = null;
IntRBTNode x = tree.root;
while (x != null) {
y = x;
if (z.key < x.key) {
x = x.left;
} else if (z.key > x.key) {
x = x.right;
} else { // z.key == x.key
x.element = z.element;
// No node was actually inserted.
return false;
}
}
z.parent = y;
if (y == null) {
tree.root = z;
} else if (z.key < y.key) {
y.left = z;
} else {
y.right = z;
}
return true;
}
/** Left rotation, used to keep the tree balanced. See CLR. */
private final void leftRotate(IntRedBlackTree tree) {
IntRBTNode y = this.right;
this.right = y.left;
if (y.left != null) {
y.left.parent = this;
}
y.parent = this.parent;
if (this.parent == null) {
tree.root = y;
} else if (this == this.parent.left) {
this.parent.left = y;
} else {
this.parent.right = y;
}
y.left = this;
this.parent = y;
return;
}
/** Right rotation, used to keep the tree balanced. See CLR. */
private final void rightRotate(IntRedBlackTree tree) {
IntRBTNode y = this.left;
this.left = y.right;
if (y.right != null) {
y.right.parent = this;
}
y.parent = this.parent;
if (this.parent == null) {
tree.root = y;
} else if (this == this.parent.right) {
this.parent.right = y;
} else {
this.parent.left = y;
}
y.right = this;
this.parent = y;
return;
}
/**
* Delete a given node from the tree. The node must be contained in the tree! Our code is more
* complicated than CLR because we don't use a NIL sentinel.
*/
static final void delete(IntRedBlackTree tree, IntRBTNode z) {
IntRBTNode x;
IntRBTNode y;
IntRBTNode xParent = null;
if (z.left == null || z.right == null) {
y = z;
} else {
y = z.successor();
}
if (y.left != null) {
x = y.left;
} else {
x = y.right;
}
if (x != null) {
x.parent = y.parent;
} else {
xParent = y.parent;
}
if (y.parent == null) {
tree.root = x;
} else {
if (y == y.parent.left) {
y.parent.left = x;
} else {
y.parent.right = x;
}
}
if (y != z) {
z.key = y.key;
z.element = y.element;
}
if (y.color == BLACK) {
if (x == null) {
deleteFixupNull(tree, xParent);
} else {
deleteFixup(tree, x);
}
}
}
/** From CLR. x must not be null. */
private static final void deleteFixup(IntRedBlackTree tree, IntRBTNode x) {
IntRBTNode w;
while (x != tree.root && x.color == BLACK) {
if (x == x.parent.left) {
w = x.parent.right;
if (w.color == RED) {
w.color = BLACK;
x.parent.color = RED;
x.parent.leftRotate(tree);
w = x.parent.right;
}
if (colorOf(leftOf(w)) == BLACK && colorOf(rightOf(w)) == BLACK) {
w.color = RED;
x = x.parent;
} else {
if (colorOf(rightOf(w)) == BLACK) {
w.color = RED;
w.rightRotate(tree);
w = x.parent.right;
}
w.color = x.parent.color;
x.parent.color = BLACK;
if (w.right != null) {
w.right.color = BLACK;
}
x.parent.leftRotate(tree);
x = tree.root;
}
} else {
w = x.parent.left;
if (w.color == RED) {
w.color = BLACK;
x.parent.color = RED;
x.parent.rightRotate(tree);
w = x.parent.left;
}
if (colorOf(rightOf(w)) == BLACK && colorOf(leftOf(w)) == BLACK) {
w.color = RED;
x = x.parent;
} else {
if (colorOf(leftOf(w)) == BLACK) {
w.color = RED;
w.leftRotate(tree);
w = x.parent.left;
}
w.color = x.parent.color;
x.parent.color = BLACK;
if (w.left != null) {
w.left.color = BLACK;
}
x.parent.rightRotate(tree);
x = tree.root;
}
}
}
x.color = BLACK;
}
/**
* Like deleteFixup(), only that the node we should be working on is null, and we actually hand in
* the node's mother. Special case because we don't use sentinels.
*/
private static final void deleteFixupNull(IntRedBlackTree tree, IntRBTNode x) {
// if x == null, we just deleted the only node in the tree
if (x == null) {
return;
}
IntRBTNode w;
if (x.left == null) {
w = x.right;
if (w.color == RED) {
w.color = BLACK;
x.color = RED;
x.leftRotate(tree);
w = x.right;
}
if (colorOf(leftOf(w)) == BLACK && colorOf(rightOf(w)) == BLACK) {
w.color = RED;
} else {
if (colorOf(rightOf(w)) == BLACK) {
w.color = RED;
w.rightRotate(tree);
w = x.right;
}
w.color = x.color;
x.color = BLACK;
if (w.right != null) {
w.right.color = BLACK;
}
x.leftRotate(tree);
x = tree.root;
}
} else {
w = x.left;
if (w.color == RED) {
w.color = BLACK;
x.color = RED;
x.rightRotate(tree);
w = x.left;
}
if (colorOf(rightOf(w)) == BLACK && colorOf(leftOf(w)) == BLACK) {
w.color = RED;
} else {
if (colorOf(leftOf(w)) == BLACK) {
w.color = RED;
w.leftRotate(tree);
w = x.left;
}
w.color = x.color;
x.color = BLACK;
if (w.left != null) {
w.left.color = BLACK;
}
x.rightRotate(tree);
x = tree.root;
}
}
while (x != tree.root && x.color == BLACK) {
if (x == x.parent.left) {
w = x.parent.right;
if (w.color == RED) {
w.color = BLACK;
x.parent.color = RED;
x.parent.leftRotate(tree);
w = x.parent.right;
}
if (colorOf(leftOf(w)) == BLACK && colorOf(rightOf(w)) == BLACK) {
w.color = RED;
x = x.parent;
} else {
if (colorOf(rightOf(w)) == BLACK) {
w.color = RED;
w.rightRotate(tree);
w = x.parent.right;
}
w.color = x.parent.color;
x.parent.color = BLACK;
if (w.right != null) {
w.right.color = BLACK;
}
x.parent.leftRotate(tree);
x = tree.root;
}
} else {
w = x.parent.left;
if (w.color == RED) {
w.color = BLACK;
x.parent.color = RED;
x.parent.rightRotate(tree);
w = x.parent.left;
}
if (colorOf(rightOf(w)) == BLACK && colorOf(leftOf(w)) == BLACK) {
w.color = RED;
x = x.parent;
} else {
if (colorOf(leftOf(w)) == BLACK) {
w.color = RED;
w.leftRotate(tree);
w = x.parent.left;
}
w.color = x.parent.color;
x.parent.color = BLACK;
if (w.left != null) {
w.left.color = BLACK;
}
x.parent.rightRotate(tree);
x = tree.root;
}
}
}
x.color = BLACK;
}
/**
* Fill an array with the keys contained in the tree. The array must at least have the size of the
* tree! Returns the size of the tree, for internal reasons.
*/
int keys(int pos, int[] keys) {
int cur = pos;
if (this.left != null) {
cur = this.left.keys(cur, keys);
}
keys[cur] = this.key;
++cur;
if (this.right != null) {
cur = this.right.keys(cur, keys);
}
return cur;
}
/**
* Create an array representation for the tree under this node. See
* {@link org.apache.uima.internal.util.rb_trees.IntRBTArray IntRBTArray} for a definition of the
* resulting array format.
*
* @param offset
* See
* {@link org.apache.uima.internal.util.rb_trees.IntRedBlackTree#toArray IntRedBlackTree.toArray()}
* for comments.
* @return The generated array.
*/
int[] toArray(int offset) {
// This will hold the new array.
IntVector v = new IntVector();
// A stack for traversing the tree;
Stack<IntRBTNode> nodeStack = new Stack<IntRBTNode>();
// A stack for keeping addresses associated w/ the nodes on the
// node stack.
IntStack addressStack = new IntStack();
IntRBTNode node = this;
int address;
do {
while (node.left != null || node.right != null) {
// While we have a non-terminal node...
v.add(node.key);
v.add(node.element);
if (node.left != null) {
if (node.right != null) {
v.add(IntRBTArray.TWODTRS);
addressStack.push(v.size());
v.add(-1); // Placeholder.
nodeStack.push(node.right);
} else {
v.add(IntRBTArray.LEFTDTR);
}
node = node.left;
} else {
// Because of the while loop, we know at this point that
// node.right != null
v.add(IntRBTArray.RIGHTDTR);
node = node.right;
}
}
// We have reached a terminal node...
v.add(node.key);
v.add(node.element);
v.add(IntRBTArray.TERMINAL);
if (addressStack.empty()) {
node = null;
} else {
node = (IntRBTNode) nodeStack.pop();
address = addressStack.pop();
v.set(address, v.size() + offset);
}
} while (node != null);
return v.toArray();
}
// Use as accessor when node might be null.
private static final boolean colorOf(IntRBTNode x) {
return (x == null) ? BLACK : x.color;
}
// Below some accessor functions to be used when the node might be
// null.
// Use when node might be null.
private static final void setColor(IntRBTNode x, boolean c) {
if (x != null) {
x.color = c;
}
}
// Use when node might be null.
private static final IntRBTNode leftOf(IntRBTNode x) {
return (x == null) ? null : x.left;
}
// Use when node might be null.
private static final IntRBTNode rightOf(IntRBTNode x) {
return (x == null) ? null : x.right;
}
// Debugging aid.
public void printKeys(int indent) {
for (int i = 0; i < indent; i++) {
System.out.print(' ');
}
System.out.print(this.key);
System.out.print(":");
if (this.color == RED) {
System.out.println("red");
} else {
System.out.println("black");
}
indent += indentInc;
if (this.left != null) {
this.left.printKeys(indent);
}
if (this.right != null) {
this.right.printKeys(indent);
}
return;
}
// Debugging aid.
public void printElements(int indent) {
for (int i = 0; i < indent; i++) {
System.out.print(' ');
}
System.out.println(this.element);
indent += indentInc;
if (this.left != null) {
this.left.printElements(indent);
}
if (this.right != null) {
this.right.printElements(indent);
}
return;
}
IntRBTNode copyNode(IntRBTNode parent) {
IntRBTNode copyOfNode = new IntRBTNode(key, color, parent, null, null, element);
copyOfNode.left = copyNode(copyOfNode, left);
copyOfNode.right = copyNode(copyOfNode, right);
return copyOfNode;
}
static IntRBTNode copyNode(IntRBTNode parent, IntRBTNode n) {
if (null == n) {
return null;
}
return n.copyNode(parent);
}
}