SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package net.multiphasicapps.squirrelquarrel.util;

import java.util.Random;

/**
 * This is the random number generator, this allows the seed to be obtained
 * and set so that it is restored properly.
 *
 * {@squirreljme.error BE0f Floating point operations not supported.}
 *
 * @since 2017/02/10
 */
public class GameRandom
    extends Random
{
    /** The current seed. */
    protected volatile long seed;    
    
    /**
     * Initializes the random number generator with the given seed.
     *
     * @param __s The seed to use.
     * @since 2017/02/10
     */
    public GameRandom(long __s)
    {
        this.setSeed(__s);
    }
    
    /**
     * Returns the current raw seed value.
     *
     * @return The current raw seed value.
     * @since 2017/02/10
     */
    public long getRawSeed()
    {
        return this.seed;
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/02/10
     */
    @Override
    protected int next(int __b)
    {
        // Setup new seed value
        long seed = this.seed;
        seed = (seed * 0x5DEECE66DL + 0xBL) & ((1L << 48) - 1);
        this.seed = seed;
        
        // Return from the old seed
        return (int)(seed >>> (48 - __b));
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/02/10
     */
    @Override
    public double nextDouble()
    {
        throw new UnsupportedOperationException("BE0f");
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/02/10
     */
    @Override
    public float nextFloat()
    {
        throw new UnsupportedOperationException("BE0f");
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/02/10
     */
    @Override
    public double nextGaussian()
    {
        throw new UnsupportedOperationException("BE0f");
    }
    
    /**
     * Sets the current raw seed value.
     *
     * @param __s The raw seed value to use.
     * @since 2017/02/10
     */
    public void setRawSeed(long __s)
    {
        this.seed = __s;
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/02/10
     */
    @Override
    public void setSeed(long __s)
    {
        // Update
        this.seed = (__s ^ 0x5DEECE66DL) & ((1L << 48) - 1);
    }
}