/*
* The Apache Software License, Version 1.1
*
*
* Copyright (c) 1999 The Apache Software Foundation. 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.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Xalan" and "Apache Software Foundation" must
* not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache",
* nor may "Apache" appear in their name, without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 THE APACHE SOFTWARE FOUNDATION OR
* ITS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, Lotus
* Development Corporation., http://www.lotus.com. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
package org.apache.xml.utils;
import java.util.EmptyStackException;
/**
* <meta name="usage" content="internal"/>
* Simple stack for boolean values.
*/
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;
}
/**
* 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();
}
}