minecraft-src/net/minecraft/world/level/chunk/DataLayer.java

package net.minecraft.world.level.chunk;

import java.util.Arrays;
import net.minecraft.Util;
import net.minecraft.util.VisibleForDebug;
import org.jetbrains.annotations.Nullable;

/**
 * A representation of a 16x16x16 cube of nibbles (half-bytes).
 */
public class DataLayer {
	public static final int LAYER_COUNT = 16;
	public static final int LAYER_SIZE = 128;
	public static final int SIZE = 2048;
	private static final int NIBBLE_SIZE = 4;
	@Nullable
	protected byte[] data;
	private int defaultValue;

	public DataLayer() {
		this(0);
	}

	public DataLayer(int size) {
		this.defaultValue = size;
	}

	public DataLayer(byte[] data) {
		this.data = data;
		this.defaultValue = 0;
		if (data.length != 2048) {
			throw (IllegalArgumentException)Util.pauseInIde(new IllegalArgumentException("DataLayer should be 2048 bytes not: " + data.length));
		}
	}

	/**
	 * Note all coordinates must be in the range [0, 16), they <strong>are not checked</strong>, and will either silently overrun the array or throw an exception.
	 * @return The value of this data layer at the provided position.
	 */
	public int get(int x, int y, int z) {
		return this.get(getIndex(x, y, z));
	}

	/**
	 * Sets the value of this data layer at the provided position.
	 * Note all coordinates must be in the range [0, 16), they <strong>are not checked</strong>, and will either silently overrun the array or throw an exception.
	 */
	public void set(int x, int y, int z, int value) {
		this.set(getIndex(x, y, z), value);
	}

	private static int getIndex(int x, int y, int z) {
		return y << 8 | z << 4 | x;
	}

	private int get(int index) {
		if (this.data == null) {
			return this.defaultValue;
		} else {
			int i = getByteIndex(index);
			int j = getNibbleIndex(index);
			return this.data[i] >> 4 * j & 15;
		}
	}

	private void set(int index, int value) {
		byte[] bs = this.getData();
		int i = getByteIndex(index);
		int j = getNibbleIndex(index);
		int k = ~(15 << 4 * j);
		int l = (value & 15) << 4 * j;
		bs[i] = (byte)(bs[i] & k | l);
	}

	private static int getNibbleIndex(int index) {
		return index & 1;
	}

	private static int getByteIndex(int index) {
		return index >> 1;
	}

	public void fill(int defaultValue) {
		this.defaultValue = defaultValue;
		this.data = null;
	}

	private static byte packFilled(int value) {
		byte b = (byte)value;

		for (int i = 4; i < 8; i += 4) {
			b = (byte)(b | value << i);
		}

		return b;
	}

	public byte[] getData() {
		if (this.data == null) {
			this.data = new byte[2048];
			if (this.defaultValue != 0) {
				Arrays.fill(this.data, packFilled(this.defaultValue));
			}
		}

		return this.data;
	}

	public DataLayer copy() {
		return this.data == null ? new DataLayer(this.defaultValue) : new DataLayer((byte[])this.data.clone());
	}

	public String toString() {
		StringBuilder stringBuilder = new StringBuilder();

		for (int i = 0; i < 4096; i++) {
			stringBuilder.append(Integer.toHexString(this.get(i)));
			if ((i & 15) == 15) {
				stringBuilder.append("\n");
			}

			if ((i & 0xFF) == 255) {
				stringBuilder.append("\n");
			}
		}

		return stringBuilder.toString();
	}

	@VisibleForDebug
	public String layerToString(int unused) {
		StringBuilder stringBuilder = new StringBuilder();

		for (int i = 0; i < 256; i++) {
			stringBuilder.append(Integer.toHexString(this.get(i)));
			if ((i & 15) == 15) {
				stringBuilder.append("\n");
			}
		}

		return stringBuilder.toString();
	}

	public boolean isDefinitelyHomogenous() {
		return this.data == null;
	}

	public boolean isDefinitelyFilledWith(int value) {
		return this.data == null && this.defaultValue == value;
	}

	public boolean isEmpty() {
		return this.data == null && this.defaultValue == 0;
	}
}