/* * reserved comment block * DO NOT REMOVE OR ALTER! */ /* * Copyright 1999-2004 The Apache Software Foundation. * * Licensed 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. */ /* * $Id: BoolStack.java,v 1.2.4.1 2005/09/15 08:15:35 suresh_emailid Exp $ */ package com.sun.org.apache.xml.internal.utils; /** * Simple stack for boolean values. * @xsl.usage internal */ public final class BoolStack implements Cloneable { /** Array of boolean values */ private boolean m_values[]; /** Array size allocated */ private int m_allocatedSize; /** Index into the array of booleans */ private int m_index; /** * Default constructor. Note that the default * block size is very small, for small lists. */ public BoolStack() { this(32); } /** * Construct a IntVector, using the given block size. * * @param size array size to allocate */ public BoolStack(int size) { m_allocatedSize = size; m_values = new boolean[size]; m_index = -1; } /** * Get the length of the list. * * @return Current length of the list */ public final int size() { return m_index + 1; } /** * Clears the stack. * */ public final void clear() { m_index = -1; } /** * Pushes an item onto the top of this stack. * * * @param val the boolean to be pushed onto this stack. * @return the item argument. */ public final boolean push(boolean val) { if (m_index == m_allocatedSize - 1) grow(); return (m_values[++m_index] = val); } /** * Removes the object at the top of this stack and returns that * object as the value of this function. * * @return The object at the top of this stack. * @throws EmptyStackException if this stack is empty. */ public final boolean pop() { return m_values[m_index--]; } /** * Removes the object at the top of this stack and returns the * next object at the top as the value of this function. * * * @return Next object to the top or false if none there */ public final boolean popAndTop() { m_index--; return (m_index >= 0) ? m_values[m_index] : false; } /** * Set the item at the top of this stack * * * @param b Object to set at the top of this stack */ public final void setTop(boolean b) { m_values[m_index] = b; } /** * Looks at the object at the top of this stack without removing it * from the stack. * * @return the object at the top of this stack. * @throws EmptyStackException if this stack is empty. */ public final boolean peek() { return m_values[m_index]; } /** * Looks at the object at the top of this stack without removing it * from the stack. If the stack is empty, it returns false. * * @return the object at the top of this stack. */ public final boolean peekOrFalse() { return (m_index > -1) ? m_values[m_index] : false; } /** * Looks at the object at the top of this stack without removing it * from the stack. If the stack is empty, it returns true. * * @return the object at the top of this stack. */ public final boolean peekOrTrue() { return (m_index > -1) ? m_values[m_index] : true; } /** * Tests if this stack is empty. * * @return true if this stack is empty; * false otherwise. */ public boolean isEmpty() { return (m_index == -1); } /** * Grows the size of the stack * */ private void grow() { m_allocatedSize *= 2; boolean newVector[] = new boolean[m_allocatedSize]; System.arraycopy(m_values, 0, newVector, 0, m_index + 1); m_values = newVector; } public Object clone() throws CloneNotSupportedException { return super.clone(); } }