/* * reserved comment block * DO NOT REMOVE OR ALTER! */ /* * 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 1.2.4.1 2005/09/15 08:15:45 suresh_emailid 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 item 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 true if this stack is empty; * false 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 -1 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(); } }