| /* |
| * 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: IntStack.java 468655 2006-10-28 07:12:06Z minchau $ |
| */ |
| package org.apache.xml.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(); |
| } |
| } |