Paper/src/main/java/org/bukkit/craftbukkit/CraftChunkSnapshot.java

package org.bukkit.craftbukkit;

import org.bukkit.ChunkSnapshot;
import org.bukkit.block.Biome;
import org.bukkit.craftbukkit.block.CraftBlock;

import net.minecraft.server.BiomeBase;

/**
 * Represents a static, thread-safe snapshot of chunk of blocks
 * Purpose is to allow clean, efficient copy of a chunk data to be made, and then handed off for processing in another thread (e.g. map rendering)
 */
public class CraftChunkSnapshot implements ChunkSnapshot {
    private final int x, z;
    private final String worldname;
    private final byte[] buf; // Flat buffer in uncompressed chunk file format
    private final byte[] hmap; // Height map
    private final long captureFulltime;
    private final BiomeBase[] biome;
    private final double[] biomeTemp;
    private final double[] biomeRain;

    private static final int BLOCKDATA_OFF = 32768;
    private static final int BLOCKLIGHT_OFF = BLOCKDATA_OFF + 16384;
    private static final int SKYLIGHT_OFF = BLOCKLIGHT_OFF + 16384;

    CraftChunkSnapshot(int x, int z, String wname, long wtime, byte[] buf, byte[] hmap, BiomeBase[] biome, double[] biomeTemp, double[] biomeRain) {
        this.x = x;
        this.z = z;
        this.worldname = wname;
        this.captureFulltime = wtime;
        this.buf = buf;
        this.hmap = hmap;
        this.biome = biome;
        this.biomeTemp = biomeTemp;
        this.biomeRain = biomeRain;
    }

    public int getX() {
        return x;
    }

    public int getZ() {
        return z;
    }

    public String getWorldName() {
        return worldname;
    }

    public int getBlockTypeId(int x, int y, int z) {
        return buf[x << 11 | z << 7 | y] & 255;
    }

    public int getBlockData(int x, int y, int z) {
        int off = ((x << 10) | (z << 6) | (y >> 1)) + BLOCKDATA_OFF;

        return ((y & 1) == 0) ? (buf[off] & 0xF) : ((buf[off] >> 4) & 0xF);
    }

    public int getBlockSkyLight(int x, int y, int z) {
        int off = ((x << 10) | (z << 6) | (y >> 1)) + SKYLIGHT_OFF;

        return ((y & 1) == 0) ? (buf[off] & 0xF) : ((buf[off] >> 4) & 0xF);
    }

    public int getBlockEmittedLight(int x, int y, int z) {
        int off = ((x << 10) | (z << 6) | (y >> 1)) + BLOCKLIGHT_OFF;

        return ((y & 1) == 0) ? (buf[off] & 0xF) : ((buf[off] >> 4) & 0xF);
    }

    public int getHighestBlockYAt(int x, int z) {
        return hmap[z << 4 | x] & 255;
    }

    public Biome getBiome(int x, int z) {
        return CraftBlock.biomeBaseToBiome(biome[z << 4 | x]);
    }

    public double getRawBiomeTemperature(int x, int z) {
        return biomeTemp[z << 4 | x];
    }

    public double getRawBiomeRainfall(int x, int z) {
        return biomeRain[z << 4 | x];
    }

    public long getCaptureFullTime() {
        return captureFulltime;
    }
}