| /* |
| * 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. |
| */ |
| /* |
| * $Id: BoolStack.java 468655 2006-10-28 07:12:06Z minchau $ |
| */ |
| package org.apache.xml.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 <code>item</code> 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 <code>true</code> if this stack is empty; |
| * <code>false</code> 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(); |
| } |
| |
| } |