runtime/ObjC/Framework/IntArray.h

/*
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 Copyright (c) 2005-2008 Terence Parr
 All rights reserved.

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 1. Redistributions of source code must retain the above copyright
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    documentation and/or other materials provided with the distribution.
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    derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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*/
package org.antlr.runtime.misc;

/** A dynamic array that uses int not Integer objects. In principle this
 *  is more efficient in time, but certainly in space.
 *
 *  This is simple enough that you can access the data array directly,
 *  but make sure that you append elements only with add() so that you
 *  get dynamic sizing.  Make sure to call ensureCapacity() when you are
 *  manually adding new elements.
 *
 *  Doesn't impl List because it doesn't return objects and I mean this
 *  really as just an array not a List per se.  Manipulate the elements
 *  at will.  This has stack methods too.
 *
 *  When runtime can be 1.5, I'll make this generic.
 */
public class IntArray {
	public static final int INITIAL_SIZE = 10;
	public int[] data;
	protected int p = -1;

	public void add(int v) {
		ensureCapacity(p+1);
		data[++p] = v;
	}

	public void push(int v) {
		add(v);
	}

	public int pop() {
		int v = data[p];
		p--;
		return v;
	}

	/** This only tracks elements added via push/add. */
	public int size() {
		return p;
	}

    public void clear() {
        p = -1;
    }

    public void ensureCapacity(int index) {
		if ( data==null ) {
			data = new int[INITIAL_SIZE];
		}
		else if ( (index+1)>=data.length ) {
			int newSize = data.length*2;
			if ( index>newSize ) {
				newSize = index+1;
			}
			int[] newData = new int[newSize];
			System.arraycopy(data, 0, newData, 0, data.length);
			data = newData;
		}
	}
}