RPGRandom.java

package fr.wolf.game.utils;

import java.util.Random;

@SuppressWarnings("serial")
public class RPGRandom extends Random
{
    private long[] state;
    private int index;

    public RPGRandom()
    {
        this((int)System.currentTimeMillis());
    }

    public RPGRandom(int seed)
    {
        state = new long[16];
        index = 0;
        seed(seed);
    }

    private void seed(int seed)
    {
        seed = Math.abs(seed);

        for(int i = 0; i < 16; i++)
        {
            state[i] = (seed + 1) * ((seed + 1) << 2) * i;
        }
    }

    @Override
    protected int next(int nbits)
    {
        long a, b, c, d;
        a = state[index];
        c = state[(index + 13) & 15];
        b = a ^ c ^ (a << 16) ^ (c << 15);
        c = state[(index + 9) & 15];
        c ^= c >> 11;
        a = state[index] = b ^ c;
        d = a ^ ((a << 5) & 0xDA442D24L);
        index = (index + 15) & 15;
        a = state[index];
        state[index] = a ^ b ^ d ^ (a << 2) ^ (b << 18) ^ (c << 28);
        return (int)state[index];
    }
}