/*******************************************************************************
 * Copyright (c) 2009 MATERNA Information & Communications. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html. For further
 * project-related information visit http://www.ws4d.org. The most recent
 * version of the JMEDS framework can be obtained from
 * http://sourceforge.net/projects/ws4d-javame.
 ******************************************************************************/
package org.ws4d.java.util;

import java.util.Random;

/**
 * Some maths functions missing on CLDC.
 */
public final class Math {

	private static Random	r	= new Random(System.currentTimeMillis());

	/**
	 * Returns a random value in the range [min, max[. When min == max, returns
	 * min. When min > max, returns nextInt(max, min).
	 * 
	 * @param min The lower bound. Inclusive.
	 * @param max The upper bound. Exclusive.
	 * @return a random value in the range [min, max[.
	 */
	public static int nextInt(int min, int max) {
		if (max == min) {
			return max;
		}
		if (min > max) {
			return nextInt(max, min);
		}
		int range = max - min;
		int val = java.lang.Math.abs(r.nextInt() % range);
		return val + min;
	}

	/**
	 * Returns a random value in the range [0, max[.
	 * 
	 * @param max The upper bound. Exclusive.
	 * @return a random value in the range [0, max[.
	 */
	public static int nextInt(int max) {
		return Math.nextInt(0, max);
	}

	/**
	 * Returns a random integer value.
	 * 
	 * @return a random integer value.
	 */
	public static int nextInt() {
		return r.nextInt();
	}

	/**
	 * Generates a random port number between 1025 and 65535.
	 * 
	 * @return a random number to try as port number for the server.
	 */
	public static int getRandomPortNumber() {
		return (r.nextInt() & 0xefff) + 1025;
	}

	/**
	 * Returns the Random generated by MathUtil.
	 * 
	 * @return <code>Random</code>;
	 */
	public static Random getRandom() {
		return r;
	}

	public static int pow(int a, int b) {
		if (b == 0) return 1;
		if (b == 1) return a;
		int c = a;
		while (b > 1) {
			a = a * c;
			b--;
		}
		return a;
	}
}