/*

 * 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.xerces.internal.util;

/**

 * A simple integer based stack.

 *

 * moved to com.sun.org.apache.xerces.internal.util by neilg to support the

 * XPathMatcher.

 * @author  Andy Clark, IBM

 *

 */

public final class IntStack {

    //

    // Data

    //

    /** Stack depth. */

    private int fDepth;

    /** Stack data. */

    private int[] fData;

    //

    // Public methods

    //

    /** Returns the size of the stack. */

    public int size() {

        return fDepth;

    }

    /** Pushes a value onto the stack. */

    public void push(int value) {

        ensureCapacity(fDepth + 1);

        fData[fDepth++] = value;

    }

    /** Peeks at the top of the stack. */

    public int peek() {

        return fData[fDepth - 1];

    }

    /** Returns the element at the specified depth in the stack. */

    public int elementAt(int depth) {

        return fData[depth];

    }

    /** Pops a value off of the stack. */

    public int pop() {

        return fData[--fDepth];

    }

    /** Clears the stack. */

    public void clear() {

        fDepth = 0;

    }

    // debugging

    /** Prints the stack. */

    public void print() {

        System.out.print('(');

        System.out.print(fDepth);

        System.out.print(") {");

        for (int i = 0; i < fDepth; i++) {

            if (i == 3) {

                System.out.print(" ...");

                break;

            }

            System.out.print(' ');

            System.out.print(fData[i]);

            if (i < fDepth - 1) {

                System.out.print(',');

            }

        }

        System.out.print(" }");

        System.out.println();

    }

    //

    // Private methods

    //

    /** Ensures capacity. */

    private void ensureCapacity(int size) {

        if (fData == null) {

            fData = new int[32];

        }

        else if (fData.length <= size) {

            int[] newdata = new int[fData.length * 2];

            System.arraycopy(fData, 0, newdata, 0, fData.length);

            fData = newdata;

        }

    }

} // class IntStack