Code/net/minecraft/world/level/levelgen/XoroshiroRandomSource.java

package net.minecraft.world.level.levelgen;

import com.google.common.annotations.VisibleForTesting;
import com.mojang.serialization.Codec;
import net.minecraft.util.Mth;
import net.minecraft.util.RandomSource;

public class XoroshiroRandomSource implements RandomSource {
    private static final float FLOAT_UNIT = 5.9604645E-8F;
    private static final double DOUBLE_UNIT = 1.110223E-16F;
    public static final Codec<XoroshiroRandomSource> CODEC = Xoroshiro128PlusPlus.CODEC
        .xmap(p_287645_ -> new XoroshiroRandomSource(p_287645_), p_287690_ -> p_287690_.randomNumberGenerator);
    private Xoroshiro128PlusPlus randomNumberGenerator;
    private final MarsagliaPolarGaussian gaussianSource = new MarsagliaPolarGaussian(this);

    public XoroshiroRandomSource(long p_190102_) {
        this.randomNumberGenerator = new Xoroshiro128PlusPlus(RandomSupport.upgradeSeedTo128bit(p_190102_));
    }

    public XoroshiroRandomSource(RandomSupport.Seed128bit p_289014_) {
        this.randomNumberGenerator = new Xoroshiro128PlusPlus(p_289014_);
    }

    public XoroshiroRandomSource(long p_190104_, long p_190105_) {
        this.randomNumberGenerator = new Xoroshiro128PlusPlus(p_190104_, p_190105_);
    }

    private XoroshiroRandomSource(Xoroshiro128PlusPlus p_287656_) {
        this.randomNumberGenerator = p_287656_;
    }

    @Override
    public RandomSource fork() {
        return new XoroshiroRandomSource(this.randomNumberGenerator.nextLong(), this.randomNumberGenerator.nextLong());
    }

    @Override
    public PositionalRandomFactory forkPositional() {
        return new XoroshiroRandomSource.XoroshiroPositionalRandomFactory(this.randomNumberGenerator.nextLong(), this.randomNumberGenerator.nextLong());
    }

    @Override
    public void setSeed(long p_190121_) {
        this.randomNumberGenerator = new Xoroshiro128PlusPlus(RandomSupport.upgradeSeedTo128bit(p_190121_));
        this.gaussianSource.reset();
    }

    @Override
    public int nextInt() {
        return (int)this.randomNumberGenerator.nextLong();
    }

    @Override
    public int nextInt(int p_190118_) {
        if (p_190118_ <= 0) {
            throw new IllegalArgumentException("Bound must be positive");
        } else {
            long i = Integer.toUnsignedLong(this.nextInt());
            long j = i * p_190118_;
            long k = j & 4294967295L;
            if (k < p_190118_) {
                for (int l = Integer.remainderUnsigned(~p_190118_ + 1, p_190118_); k < l; k = j & 4294967295L) {
                    i = Integer.toUnsignedLong(this.nextInt());
                    j = i * p_190118_;
                }
            }

            long i1 = j >> 32;
            return (int)i1;
        }
    }

    @Override
    public long nextLong() {
        return this.randomNumberGenerator.nextLong();
    }

    @Override
    public boolean nextBoolean() {
        return (this.randomNumberGenerator.nextLong() & 1L) != 0L;
    }

    @Override
    public float nextFloat() {
        return (float)this.nextBits(24) * 5.9604645E-8F;
    }

    @Override
    public double nextDouble() {
        return this.nextBits(53) * 1.110223E-16F;
    }

    @Override
    public double nextGaussian() {
        return this.gaussianSource.nextGaussian();
    }

    @Override
    public void consumeCount(int p_190111_) {
        for (int i = 0; i < p_190111_; i++) {
            this.randomNumberGenerator.nextLong();
        }
    }

    private long nextBits(int p_190108_) {
        return this.randomNumberGenerator.nextLong() >>> 64 - p_190108_;
    }

    public static class XoroshiroPositionalRandomFactory implements PositionalRandomFactory {
        private final long seedLo;
        private final long seedHi;

        public XoroshiroPositionalRandomFactory(long p_190127_, long p_190128_) {
            this.seedLo = p_190127_;
            this.seedHi = p_190128_;
        }

        @Override
        public RandomSource at(int p_224691_, int p_224692_, int p_224693_) {
            long i = Mth.getSeed(p_224691_, p_224692_, p_224693_);
            long j = i ^ this.seedLo;
            return new XoroshiroRandomSource(j, this.seedHi);
        }

        @Override
        public RandomSource fromHashOf(String p_224695_) {
            RandomSupport.Seed128bit randomsupport$seed128bit = RandomSupport.seedFromHashOf(p_224695_);
            return new XoroshiroRandomSource(randomsupport$seed128bit.xor(this.seedLo, this.seedHi));
        }

        @Override
        public RandomSource fromSeed(long p_343733_) {
            return new XoroshiroRandomSource(p_343733_ ^ this.seedLo, p_343733_ ^ this.seedHi);
        }

        @VisibleForTesting
        @Override
        public void parityConfigString(StringBuilder p_190136_) {
            p_190136_.append("seedLo: ").append(this.seedLo).append(", seedHi: ").append(this.seedHi);
        }
    }
}