- /*
- * 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: IntStack.java,v 1.11 2004/02/17 04:21:14 minchau Exp $
- */
- package com.sun.org.apache.xml.internal.utils;
-
- import java.util.EmptyStackException;
-
- /**
- * Implement a stack of simple integers.
- *
- * %OPT%
- * This is currently based on IntVector, which permits fast acess but pays a
- * heavy recopying penalty if/when its size is increased. If we expect deep
- * stacks, we should consider a version based on ChunkedIntVector.
- * @xsl.usage internal
- */
- public class IntStack extends IntVector
- {
-
- /**
- * Default constructor. Note that the default
- * block size is very small, for small lists.
- */
- public IntStack()
- {
- super();
- }
-
- /**
- * Construct a IntVector, using the given block size.
- *
- * @param blocksize Size of block to allocate
- */
- public IntStack(int blocksize)
- {
- super(blocksize);
- }
-
- /**
- * Copy constructor for IntStack
- *
- * @param v IntStack to copy
- */
- public IntStack (IntStack v)
- {
- super(v);
- }
-
- /**
- * Pushes an item onto the top of this stack.
- *
- * @param i the int to be pushed onto this stack.
- * @return the <code>item</code> argument.
- */
- public int push(int i)
- {
-
- if ((m_firstFree + 1) >= m_mapSize)
- {
- m_mapSize += m_blocksize;
-
- int newMap[] = new int[m_mapSize];
-
- System.arraycopy(m_map, 0, newMap, 0, m_firstFree + 1);
-
- m_map = newMap;
- }
-
- m_map[m_firstFree] = i;
-
- m_firstFree++;
-
- return i;
- }
-
- /**
- * 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.
- */
- public final int pop()
- {
- return m_map[--m_firstFree];
- }
-
- /**
- * Quickly pops a number of items from the stack.
- */
-
- public final void quickPop(int n)
- {
- m_firstFree -= n;
- }
-
- /**
- * 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 int peek()
- {
- try {
- return m_map[m_firstFree - 1];
- }
- catch (ArrayIndexOutOfBoundsException e)
- {
- throw new EmptyStackException();
- }
- }
-
- /**
- * Looks at the object at the position the stack counting down n items.
- *
- * @param n The number of items down, indexed from zero.
- * @return the object at n items down.
- * @throws EmptyStackException if this stack is empty.
- */
- public int peek(int n)
- {
- try {
- return m_map[m_firstFree-(1+n)];
- }
- catch (ArrayIndexOutOfBoundsException e)
- {
- throw new EmptyStackException();
- }
- }
-
- /**
- * Sets an object at a the top of the statck
- *
- *
- * @param val object to set at the top
- * @throws EmptyStackException if this stack is empty.
- */
- public void setTop(int val)
- {
- try {
- m_map[m_firstFree - 1] = val;
- }
- catch (ArrayIndexOutOfBoundsException e)
- {
- throw new EmptyStackException();
- }
- }
-
- /**
- * Tests if this stack is empty.
- *
- * @return <code>true</code> if this stack is empty;
- * <code>false</code> otherwise.
- * @since JDK1.0
- */
- public boolean empty()
- {
- return m_firstFree == 0;
- }
-
- /**
- * Returns where an object is on this stack.
- *
- * @param o the desired object.
- * @return the distance from the top of the stack where the object is]
- * located; the return value <code>-1</code> indicates that the
- * object is not on the stack.
- * @since JDK1.0
- */
- public int search(int o)
- {
-
- int i = lastIndexOf(o);
-
- if (i >= 0)
- {
- return size() - i;
- }
-
- return -1;
- }
-
- /**
- * Returns clone of current IntStack
- *
- * @return clone of current IntStack
- */
- public Object clone()
- throws CloneNotSupportedException
- {
- return (IntStack) super.clone();
- }
- }