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	/*
	* reserved comment block
	* DO NOT REMOVE OR ALTER!
	*/
	/*
	* 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 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 <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();
	}

	}

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