xref: /external/antlr/antlr-3.4/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.
 3. The name of the author may not be used to endorse or promote products
    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;
		}
	}
}