Start work on chunks

- There are probably many errors and issues with this code (some dumb ones probably). As of right now it crashes the client.

connector/pom.xml

@@ -72,15 +72,9 @@
             <scope>compile</scope>
         </dependency>
         <dependency>
-            <groupId>com.nukkitx.protocol</groupId>
-            <artifactId>bedrock-v354</artifactId>
-            <version>2.1.2</version>
-            <scope>compile</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.nukkitx.protocol</groupId>
-            <artifactId>bedrock-v340</artifactId>
-            <version>2.1.2</version>
+            <groupId>com.nukkitx</groupId>
+            <artifactId>fastutil-lite</artifactId>
+            <version>8.1.1</version>
             <scope>compile</scope>
         </dependency>
         <dependency>

connector/src/main/java/org/geysermc/connector/GeyserConnector.java

@@ -43,7 +43,6 @@ import org.geysermc.connector.console.GeyserLogger;
 import org.geysermc.connector.metrics.Metrics;
 import org.geysermc.connector.network.ConnectorServerEventHandler;
 import org.geysermc.connector.network.remote.RemoteJavaServer;
-import org.geysermc.connector.network.session.GeyserSession;
 import org.geysermc.connector.network.translators.TranslatorsInit;
 import org.geysermc.connector.plugin.GeyserPluginLoader;
 import org.geysermc.connector.plugin.GeyserPluginManager;

connector/src/main/java/org/geysermc/connector/entity/attribute/Attribute.java

@@ -27,8 +27,10 @@ package org.geysermc.connector.entity.attribute;
 
 import lombok.AllArgsConstructor;
 import lombok.Getter;
+import lombok.Setter;
 
 @Getter
+@Setter
 @AllArgsConstructor
 public class Attribute {
 

connector/src/main/java/org/geysermc/connector/network/translators/item/ItemTranslator.java

@@ -98,6 +98,9 @@ public class ItemTranslator {
 
     public static BedrockItem getBedrockBlock(BlockState stack) {
         Map<String, Object> m = Remapper.JAVA_TO_BEDROCK_BLOCKS.get(stack.getId());
+        if (m == null)
+            return BedrockItem.AIR;
+
         return new BedrockItem((String) m.get("name"), (Integer) m.get("id"), (Integer) m.get("data"));
     }
 

connector/src/main/java/org/geysermc/connector/network/translators/java/world/JavaChunkDataPacket.java

@@ -1,25 +1,55 @@
 package org.geysermc.connector.network.translators.java.world;
 
 import com.github.steveice10.mc.protocol.packet.ingame.server.world.ServerChunkDataPacket;
-import com.github.steveice10.packetlib.packet.Packet;
 import com.nukkitx.protocol.bedrock.packet.LevelChunkPacket;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
 import org.geysermc.connector.console.GeyserLogger;
 import org.geysermc.connector.network.session.GeyserSession;
 import org.geysermc.connector.network.translators.PacketTranslator;
-import org.geysermc.connector.utils.Chunks;
+import org.geysermc.connector.utils.ChunkUtils;
+import org.geysermc.connector.world.chunk.ChunkSection;
 
 public class JavaChunkDataPacket extends PacketTranslator<ServerChunkDataPacket> {
+
     @Override
     public void translate(ServerChunkDataPacket packet, GeyserSession session) {
-        LevelChunkPacket levelChunkPacket = new LevelChunkPacket();
 
-        Chunks.ChunkData data = Chunks.getData(packet.getColumn());
-        levelChunkPacket.setSubChunksLength(data.count);
-        levelChunkPacket.setData(data.bytes);
-        levelChunkPacket.setChunkX(packet.getColumn().getX());
-        levelChunkPacket.setChunkZ(packet.getColumn().getZ());
+        try {
+            byte[] buffer = new byte[32];
+            ChunkUtils.ChunkData chunkData = ChunkUtils.translateToBedrock(packet.getColumn());
+
+            int count = 0;
+            ChunkSection[] sections = chunkData.sections;
+            for (int i = sections.length - 1; i >= 0; i--) {
+                if (sections[i].isEmpty())
+                    continue;
+
+                count = i + 1;
+                break;
+            }
+
+            for (int i = 0; i < count; i++) {
+                ChunkUtils.putBytes(count, buffer, new byte[]{(byte) 0});
+                ChunkSection section = chunkData.sections[i];
+
+                ByteBuf byteBuf = Unpooled.buffer();
+                section.writeToNetwork(byteBuf);
+                byte[] byteData = byteBuf.array();
+                ChunkUtils.putBytes(count, buffer, byteData);
+            }
+
+            LevelChunkPacket levelChunkPacket = new LevelChunkPacket();
+            levelChunkPacket.setSubChunksLength(16);
+            levelChunkPacket.setCachingEnabled(true);
+            levelChunkPacket.setChunkX(packet.getColumn().getX());
+            levelChunkPacket.setChunkZ(packet.getColumn().getZ());
+            levelChunkPacket.setData(buffer);
+            session.getUpstream().sendPacket(levelChunkPacket);
+        } catch (Exception ex) {
+            ex.printStackTrace();
+        }
 
         GeyserLogger.DEFAULT.info("Sent chunk packet!");
-        session.getUpstream().sendPacket(levelChunkPacket);
     }
 }

connector/src/main/java/org/geysermc/connector/utils/ChunkUtils.java

@@ -0,0 +1,91 @@
+package org.geysermc.connector.utils;
+
+import com.github.steveice10.mc.protocol.data.game.chunk.BlockStorage;
+import com.github.steveice10.mc.protocol.data.game.chunk.Chunk;
+import com.github.steveice10.mc.protocol.data.game.chunk.Column;
+import com.github.steveice10.mc.protocol.data.game.world.block.BlockState;
+import org.geysermc.connector.network.translators.TranslatorsInit;
+import org.geysermc.connector.network.translators.item.BedrockItem;
+import org.geysermc.connector.world.chunk.ChunkSection;
+
+import java.util.Arrays;
+
+public class ChunkUtils {
+
+    private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
+
+    public static ChunkData translateToBedrock(Column column) {
+        ChunkData chunkData = new ChunkData();
+        chunkData.sections = new ChunkSection[16];
+        for (int i = 0; i < 16; i++) {
+            chunkData.sections[i] = new ChunkSection();
+        }
+
+        for (int y = 0; y < 256; y++) {
+            int chunkY = y >> 4;
+
+            Chunk chunk = null;
+            try {
+                chunk = column.getChunks()[chunkY];
+            } catch (Exception ex) {
+                ex.printStackTrace();
+            }
+
+            if (chunk == null || chunk.isEmpty())
+                continue;
+
+            BlockStorage storage = chunk.getBlocks();
+            for (int x = 0; x < 16; x++) {
+                for (int z = 0; z < 16; z++) {
+                    BlockState block = storage.get(x, y & 0xF, z);
+                    BedrockItem bedrockBlock = TranslatorsInit.getItemTranslator().getBedrockBlock(block);
+
+                    ChunkSection section = chunkData.sections[chunkY];
+
+                    org.geysermc.connector.world.chunk.BlockStorage blockStorage = new org.geysermc.connector.world.chunk.BlockStorage();
+                    blockStorage.setFullBlock(ChunkSection.blockPosition(x, y, z), bedrockBlock.getId());
+
+                    section.getBlockStorageArray()[0] = blockStorage;
+                    section.getBlockStorageArray()[1] = blockStorage;
+                }
+            }
+        }
+
+        return chunkData;
+    }
+
+    public static final class ChunkData {
+        public ChunkSection[] sections;
+    }
+
+    public static void putBytes(int count, byte[] buffer, byte[] bytes) {
+        if (bytes == null) {
+            return;
+        }
+
+        int minCapacity = count + bytes.length;
+        if ((minCapacity) - buffer.length > 0) {
+            int oldCapacity = buffer.length;
+            int newCapacity = oldCapacity << 1;
+
+            if (newCapacity - minCapacity < 0) {
+                newCapacity = minCapacity;
+            }
+
+            if (newCapacity - MAX_ARRAY_SIZE > 0) {
+                newCapacity = hugeCapacity(minCapacity);
+            }
+
+            buffer = Arrays.copyOf(buffer, newCapacity);
+        }
+
+        System.arraycopy(bytes, 0, buffer, count, bytes.length);
+    }
+
+    private static int hugeCapacity(int minCapacity) {
+        if (minCapacity < 0) { // overflow
+            throw new OutOfMemoryError();
+        }
+        return (minCapacity > MAX_ARRAY_SIZE) ? Integer.MAX_VALUE : MAX_ARRAY_SIZE;
+    }
+}

connector/src/main/java/org/geysermc/connector/utils/Chunks.java

@@ -1,81 +0,0 @@
-package org.geysermc.connector.utils;
-
-import com.github.steveice10.mc.protocol.data.game.chunk.Chunk;
-import com.github.steveice10.mc.protocol.data.game.chunk.Column;
-import gnu.trove.list.TByteList;
-import gnu.trove.list.array.TByteArrayList;
-import lombok.AccessLevel;
-import lombok.AllArgsConstructor;
-import org.geysermc.connector.network.translators.item.ItemTranslator;
-
-import java.util.List;
-import java.util.Objects;
-
-public class Chunks {
-
-    public static ChunkData getData(Column c) {
-        Objects.requireNonNull(c);
-
-        int count = 0;
-
-        for(Chunk chunk : c.getChunks()) {
-            if(chunk != null) {
-                count++;
-            }
-        }
-
-        int block = 0;
-
-        TByteList list = new TByteArrayList(4096 * 4);
-
-        for(int i = 0; i < 256; i++) {
-            list.add((byte) 0);
-        }
-
-        for(Chunk chunk : c.getChunks()) {
-            if (chunk != null) {
-                list.add((byte) 0);
-                for (int x = 0; x < 16; x++) {
-                    for (int y = 0; x < 16; x++) {
-                        for (int z = 0; x < 16; x++) {
-                            try {
-                                list.add((byte) ItemTranslator.getBedrockBlock(chunk.getBlocks().get(x, y, z)).getId());
-                            } catch (NullPointerException e) {
-                                list.add((byte) 0);
-                            }
-
-                            block++;
-                        }
-                    }
-                }
-
-                for (int x = 0; x < 16; x++) {
-                    for (int y = 0; x < 16; x++) {
-                        for (int z = 0; x < 16; x++) {
-                            try {
-                                list.add((byte) ItemTranslator.getBedrockBlock(chunk.getBlocks().get(x, y, z)).getData());
-                            } catch (NullPointerException e) {
-                                list.add((byte) 0);
-                            }
-
-                            block++;
-                        }
-                    }
-                }
-            }
-        }
-
-        list.add((byte) 0);
-        list.add((byte) 0);
-
-        return new ChunkData(count, list.toArray());
-    }
-
-    @AllArgsConstructor(access = AccessLevel.PACKAGE)
-    public static final class ChunkData {
-        public final int count;
-
-        public final byte[] bytes;
-
-    }
-}

connector/src/main/java/org/geysermc/connector/utils/MathUtils.java

@@ -0,0 +1,9 @@
+package org.geysermc.connector.utils;
+
+public class MathUtils {
+
+    public static int ceil(float floatNumber) {
+        int truncated = (int) floatNumber;
+        return floatNumber > truncated ? truncated + 1 : truncated;
+    }
+}

connector/src/main/java/org/geysermc/connector/utils/Toolbox.java

@@ -9,6 +9,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import org.geysermc.connector.network.translators.item.BedrockItem;
 import org.geysermc.connector.network.translators.item.JavaItem;
+import org.geysermc.connector.world.GlobalBlockPalette;
 
 import java.io.InputStream;
 import java.util.*;
@@ -38,6 +39,7 @@ public class Toolbox {
         ByteBuf b = Unpooled.buffer();
         VarInts.writeUnsignedInt(b, entries.size());
         for (Map<String, Object> e : entries) {
+            GlobalBlockPalette.registerMapping((int) e.get("id"));
             BedrockUtils.writeString(b, (String) e.get("name"));
             b.writeShortLE((int) e.get("data"));
             b.writeShortLE((int) e.get("id"));

connector/src/main/java/org/geysermc/connector/world/GlobalBlockPalette.java

@@ -0,0 +1,42 @@
+package org.geysermc.connector.world;
+
+import it.unimi.dsi.fastutil.ints.Int2IntArrayMap;
+
+import java.util.NoSuchElementException;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Adapted from NukkitX: https://github.com/NukkitX/Nukkit
+ */
+public class GlobalBlockPalette {
+
+    private static final Int2IntArrayMap legacyToRuntimeId = new Int2IntArrayMap();
+    private static final Int2IntArrayMap runtimeIdToLegacy = new Int2IntArrayMap();
+    private static final AtomicInteger runtimeIdAllocator = new AtomicInteger(0);
+
+    static {
+        legacyToRuntimeId.defaultReturnValue(-1);
+        runtimeIdToLegacy.defaultReturnValue(-1);
+    }
+
+    public static int getOrCreateRuntimeId(int id, int meta) {
+        return getOrCreateRuntimeId((id << 4) | meta);
+    }
+
+    public static int getOrCreateRuntimeId(int legacyId) throws NoSuchElementException {
+        int runtimeId = legacyToRuntimeId.get(legacyId);
+        if (!legacyToRuntimeId.containsKey(legacyId) || runtimeId == -1) {
+            //runtimeId = registerMapping(runtimeIdAllocator.incrementAndGet(), legacyId);
+           // throw new NoSuchElementException("Unmapped block registered id:" + (legacyId >>> 4) + " meta:" + (legacyId & 0xf));
+            return 0;
+        }
+        return runtimeId;
+    }
+
+    public static int registerMapping(int legacyId) {
+        int runtimeId = runtimeIdAllocator.getAndIncrement();
+        runtimeIdToLegacy.put(runtimeId, legacyId);
+        legacyToRuntimeId.put(legacyId, runtimeId);
+        return runtimeId;
+    }
+}

connector/src/main/java/org/geysermc/connector/world/chunk/BlockStorage.java

@@ -0,0 +1,110 @@
+package org.geysermc.connector.world.chunk;
+
+import com.nukkitx.network.VarInts;
+import gnu.trove.list.array.TIntArrayList;
+import io.netty.buffer.ByteBuf;
+import org.geysermc.connector.world.GlobalBlockPalette;
+import org.geysermc.connector.world.chunk.palette.Palette;
+import org.geysermc.connector.world.chunk.palette.PaletteVersion;
+
+/**
+ * Adapted from NukkitX: https://github.com/NukkitX/Nukkit
+ */
+public class BlockStorage {
+
+    private static final int SIZE = 4096;
+
+    private final TIntArrayList ids;
+    private Palette palette;
+
+    public BlockStorage() {
+        this(PaletteVersion.V2);
+    }
+
+    public BlockStorage(PaletteVersion version) {
+        this.palette = version.createPalette(SIZE);
+        this.ids = new TIntArrayList(16, -1);
+        this.ids.add(0); // Air is at the start of every palette.
+    }
+
+    private BlockStorage(Palette palette, TIntArrayList ids) {
+        this.ids = ids;
+        this.palette = palette;
+    }
+
+    public synchronized int getFullBlock(int xzy) {
+        return this.palette.get(xzy);
+    }
+
+    public synchronized void setFullBlock(int index, int legacyId) {
+        this.palette.set(index, this.idFor(legacyId));
+    }
+
+    public synchronized void writeToNetwork(ByteBuf buffer) {
+        buffer.writeByte(getPaletteHeader(palette.getVersion(), true));
+
+        for (int word : palette.getWords()) {
+            buffer.writeIntLE(word);
+        }
+
+        VarInts.writeUnsignedInt(buffer, ids.size());
+        ids.forEach(id -> {
+            VarInts.writeUnsignedInt(buffer, id);
+            return true;
+        });
+    }
+
+    public synchronized void writeToStorage(ByteBuf buffer) {
+        buffer.writeByte(getPaletteHeader(palette.getVersion(), false));
+        for (int word : palette.getWords()) {
+            buffer.writeIntLE(word);
+        }
+
+        //TODO: Write persistent NBT tags
+    }
+
+    private synchronized void onResize(PaletteVersion version) {
+        Palette oldPalette = this.palette;
+        this.palette = version.createPalette(SIZE);
+
+        for (int i = 0; i < SIZE; i++) {
+            this.palette.set(i, oldPalette.get(i));
+        }
+    }
+
+    private int idFor(int legacyId) {
+        int runtimeId = GlobalBlockPalette.getOrCreateRuntimeId(legacyId);
+        int index = this.ids.indexOf(runtimeId);
+        if (index != -1) {
+            return index;
+        }
+
+        index = this.ids.size();
+        this.ids.add(runtimeId);
+        PaletteVersion version = this.palette.getVersion();
+        if (index > version.getMaxEntryValue()) {
+            PaletteVersion next = version.next();
+            if (next != null) {
+                this.onResize(next);
+            }
+        }
+        return index;
+    }
+
+    private static int getPaletteHeader(PaletteVersion version, boolean runtime) {
+        return (version.getVersion() << 1) | (runtime ? 1 : 0);
+    }
+
+    public boolean isEmpty() {
+        for (int word : this.palette.getWords()) {
+            if (word != 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public BlockStorage copy() {
+        return new BlockStorage(this.palette.copy(), new TIntArrayList(this.ids));
+    }
+}

connector/src/main/java/org/geysermc/connector/world/chunk/ChunkSection.java

@@ -0,0 +1,128 @@
+package org.geysermc.connector.world.chunk;
+
+import com.nukkitx.network.util.Preconditions;
+import io.netty.buffer.ByteBuf;
+import lombok.Synchronized;
+
+/**
+ * Adapted from NukkitX: https://github.com/NukkitX/Nukkit
+ */
+public class ChunkSection {
+
+    private static final int CHUNK_SECTION_VERSION = 8;
+    public static final int SIZE = 4096;
+
+    private final BlockStorage[] storage;
+    private final NibbleArray blockLight;
+    private final NibbleArray skyLight;
+
+    public ChunkSection() {
+        this(new BlockStorage[]{new BlockStorage(), new BlockStorage()}, new NibbleArray(SIZE),
+                new NibbleArray(SIZE));
+    }
+
+    public ChunkSection(BlockStorage[] blockStorage) {
+        this(blockStorage, new NibbleArray(SIZE), new NibbleArray(SIZE));
+    }
+
+    public ChunkSection(BlockStorage[] storage, byte[] blockLight, byte[] skyLight) {
+        Preconditions.checkNotNull(storage, "storage");
+        Preconditions.checkArgument(storage.length > 1, "Block storage length must be at least 2");
+        for (BlockStorage blockStorage : storage) {
+            Preconditions.checkNotNull(blockStorage, "storage");
+        }
+
+        this.storage = storage;
+        this.blockLight = new NibbleArray(blockLight);
+        this.skyLight = new NibbleArray(skyLight);
+    }
+
+    private ChunkSection(BlockStorage[] storage, NibbleArray blockLight, NibbleArray skyLight) {
+        this.storage = storage;
+        this.blockLight = blockLight;
+        this.skyLight = skyLight;
+    }
+
+    public int getFullBlock(int x, int y, int z, int layer) {
+        checkBounds(x, y, z);
+        Preconditions.checkElementIndex(layer, this.storage.length);
+        return this.storage[layer].getFullBlock(blockPosition(x, y, z));
+    }
+
+    public void setFullBlock(int x, int y, int z, int layer, int fullBlock) {
+        checkBounds(x, y, z);
+        Preconditions.checkElementIndex(layer, this.storage.length);
+        this.storage[layer].setFullBlock(blockPosition(x, y, z), fullBlock);
+    }
+
+    @Synchronized("skyLight")
+    public byte getSkyLight(int x, int y, int z) {
+        checkBounds(x, y, z);
+        return this.skyLight.get(blockPosition(x, y, z));
+    }
+
+    @Synchronized("skyLight")
+    public void setSkyLight(int x, int y, int z, byte val) {
+        checkBounds(x, y, z);
+        this.skyLight.set(blockPosition(x, y, z), val);
+    }
+
+    @Synchronized("blockLight")
+    public byte getBlockLight(int x, int y, int z) {
+        checkBounds(x, y, z);
+        return this.blockLight.get(blockPosition(x, y, z));
+    }
+
+    @Synchronized("blockLight")
+    public void setBlockLight(int x, int y, int z, byte val) {
+        checkBounds(x, y, z);
+        this.blockLight.set(blockPosition(x, y, z), val);
+    }
+
+    public void writeToNetwork(ByteBuf buffer) {
+        buffer.writeByte(CHUNK_SECTION_VERSION);
+        buffer.writeByte(this.storage.length);
+        for (BlockStorage blockStorage : this.storage) {
+            blockStorage.writeToNetwork(buffer);
+        }
+    }
+
+    public NibbleArray getSkyLightArray() {
+        return skyLight;
+    }
+
+    public NibbleArray getBlockLightArray() {
+        return blockLight;
+    }
+
+    public BlockStorage[] getBlockStorageArray() {
+        return storage;
+    }
+
+    public boolean isEmpty() {
+        for (BlockStorage blockStorage : this.storage) {
+            if (!blockStorage.isEmpty()) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public ChunkSection copy() {
+        BlockStorage[] storage = new BlockStorage[this.storage.length];
+        for (int i = 0; i < storage.length; i++) {
+            storage[i] = this.storage[i].copy();
+        }
+        return new ChunkSection(storage, skyLight.copy(), blockLight.copy());
+    }
+
+    public static int blockPosition(int x, int y, int z) {
+        return (x << 8) | (z << 4) | y;
+    }
+
+    private static void checkBounds(int x, int y, int z) {
+        Preconditions.checkArgument(x >= 0 && x < 16, "x (%s) is not between 0 and 15", x);
+        Preconditions.checkArgument(y >= 0 && y < 16, "y (%s) is not between 0 and 15", y);
+        Preconditions.checkArgument(z >= 0 && z < 16, "z (%s) is not between 0 and 15", z);
+    }
+}

connector/src/main/java/org/geysermc/connector/world/chunk/NibbleArray.java

@@ -0,0 +1,70 @@
+package org.geysermc.connector.world.chunk;
+
+import com.nukkitx.network.util.Preconditions;
+
+/**
+ * Adapted from NukkitX: https://github.com/NukkitX/Nukkit
+ */
+public class NibbleArray implements Cloneable {
+
+    private final byte[] data;
+
+    public NibbleArray(int length) {
+        data = new byte[length / 2];
+    }
+
+    public NibbleArray(byte[] array) {
+        data = array;
+    }
+
+    public byte get(int index) {
+        Preconditions.checkElementIndex(index, data.length * 2);
+        byte val = data[index / 2];
+        if ((index & 1) == 0) {
+            return (byte) (val & 0x0f);
+        } else {
+            return (byte) ((val & 0xf0) >>> 4);
+        }
+    }
+
+    public void set(int index, byte value) {
+        Preconditions.checkArgument(value >= 0 && value < 16, "Nibbles must have a value between 0 and 15.");
+        Preconditions.checkElementIndex(index, data.length * 2);
+        value &= 0xf;
+        int half = index / 2;
+        byte previous = data[half];
+        if ((index & 1) == 0) {
+            data[half] = (byte) (previous & 0xf0 | value);
+        } else {
+            data[half] = (byte) (previous & 0x0f | value << 4);
+        }
+    }
+
+    public void fill(byte value) {
+        Preconditions.checkArgument(value >= 0 && value < 16, "Nibbles must have a value between 0 and 15.");
+        value &= 0xf;
+        for (int i = 0; i < data.length; i++) {
+            data[i] = (byte) ((value << 4) | value);
+        }
+    }
+
+    public void copyFrom(byte[] bytes) {
+        Preconditions.checkNotNull(bytes, "bytes");
+        Preconditions.checkArgument(bytes.length == data.length, "length of provided byte array is %s but expected %s", bytes.length,
+                data.length);
+        System.arraycopy(bytes, 0, data, 0, data.length);
+    }
+
+    public void copyFrom(NibbleArray array) {
+        Preconditions.checkNotNull(array, "array");
+        copyFrom(array.data);
+    }
+
+    public byte[] getData() {
+        return data;
+    }
+
+    public NibbleArray copy() {
+        return new NibbleArray(getData().clone());
+    }
+}

connector/src/main/java/org/geysermc/connector/world/chunk/palette/PaddedPalette.java

@@ -0,0 +1,77 @@
+package org.geysermc.connector.world.chunk.palette;
+
+import com.nukkitx.network.util.Preconditions;
+import org.geysermc.connector.utils.MathUtils;
+
+import java.util.Arrays;
+
+/**
+ * Adapted from NukkitX: https://github.com/NukkitX/Nukkit
+ */
+public class PaddedPalette implements Palette {
+
+    /**
+     * Array used to store data
+     */
+    private final int[] words;
+
+    /**
+     * Palette version information
+     */
+    private final PaletteVersion version;
+
+    /**
+     * Number of entries in this palette (<b>not</b> the length of the words array that internally backs this palette)
+     */
+    private final int size;
+
+    PaddedPalette(PaletteVersion version, int size, int[] words) {
+        this.size = size;
+        this.version = version;
+        this.words = words;
+        int expectedWordsLength = MathUtils.ceil((float) size / version.entriesPerWord);
+        if (words.length != expectedWordsLength) {
+            throw new IllegalArgumentException("Invalid length given for storage, got: " + words.length +
+                    " but expected: " + expectedWordsLength);
+        }
+    }
+
+    @Override
+    public void set(int index, int value) {
+        Preconditions.checkElementIndex(index, this.size);
+        Preconditions.checkArgument(value >= 0 && value <= this.version.maxEntryValue, "Invalid value");
+        int arrayIndex = index / this.version.entriesPerWord;
+        int offset = (index % this.version.entriesPerWord) * this.version.bits;
+
+        this.words[arrayIndex] = this.words[arrayIndex] & ~(this.version.maxEntryValue << offset) | (value & this.version.maxEntryValue) << offset;
+    }
+
+    @Override
+    public int get(int index) {
+        Preconditions.checkElementIndex(index, this.size);
+        int arrayIndex = index / this.version.entriesPerWord;
+        int offset = (index % this.version.entriesPerWord) * this.version.bits;
+
+        return (this.words[arrayIndex] >>> offset) & this.version.maxEntryValue;
+    }
+
+    @Override
+    public int size() {
+        return this.size;
+    }
+
+    @Override
+    public int[] getWords() {
+        return this.words;
+    }
+
+    @Override
+    public PaletteVersion getVersion() {
+        return this.version;
+    }
+
+    @Override
+    public Palette copy() {
+        return new PaddedPalette(this.version, this.size, Arrays.copyOf(this.words, this.words.length));
+    }
+}

connector/src/main/java/org/geysermc/connector/world/chunk/palette/Palette.java

@@ -0,0 +1,19 @@
+package org.geysermc.connector.world.chunk.palette;
+
+/**
+ * Adapted from NukkitX: https://github.com/NukkitX/Nukkit
+ */
+public interface Palette {
+
+    void set(int index, int value);
+
+    int get(int index);
+
+    int size();
+
+    int[] getWords();
+
+    PaletteVersion getVersion();
+
+    Palette copy();
+}

connector/src/main/java/org/geysermc/connector/world/chunk/palette/PaletteVersion.java

@@ -0,0 +1,64 @@
+package org.geysermc.connector.world.chunk.palette;
+
+import org.geysermc.connector.utils.MathUtils;
+
+/**
+ * Adapted from NukkitX: https://github.com/NukkitX/Nukkit
+ */
+public enum PaletteVersion {
+
+    V16(16, 2, null),
+    V8(8, 4, V16),
+    V6(6, 5, V8), // 2 bit padding
+    V5(5, 6, V6), // 2 bit padding
+    V4(4, 8, V5),
+    V3(3, 10, V4), // 2 bit padding
+    V2(2, 16, V3),
+    V1(1, 32, V2);
+
+    final byte bits;
+    final byte entriesPerWord;
+    final int maxEntryValue;
+    final PaletteVersion next;
+
+    PaletteVersion(int bits, int entriesPerWord, PaletteVersion next) {
+        this.bits = (byte) bits;
+        this.entriesPerWord = (byte) entriesPerWord;
+        this.maxEntryValue = (1 << this.bits) - 1;
+        this.next = next;
+    }
+
+    public Palette createPalette(int size) {
+        return this.createPalette(size, new int[MathUtils.ceil((float) size / entriesPerWord)]);
+    }
+
+    public byte getVersion() {
+        return bits;
+    }
+
+    public int getMaxEntryValue() {
+        return maxEntryValue;
+    }
+
+    public PaletteVersion next() {
+        return next;
+    }
+
+    public Palette createPalette(int size, int[] words) {
+        if (this == V3 || this == V5 || this == V6) {
+            // Padded palettes aren't able to use bitwise operations due to their padding.
+            return new PaddedPalette(this, size, words);
+        } else {
+            return new Pow2Palette(this, size, words);
+        }
+    }
+
+    private static PaletteVersion getVersion(int version, boolean read) {
+        for (PaletteVersion ver : values()) {
+            if ( ( !read && ver.entriesPerWord <= version ) || ( read && ver.bits == version ) ) {
+                return ver;
+            }
+        }
+        throw new IllegalArgumentException("Invalid palette version: " + version);
+    }
+}

connector/src/main/java/org/geysermc/connector/world/chunk/palette/Pow2Palette.java

@@ -0,0 +1,86 @@
+package org.geysermc.connector.world.chunk.palette;
+
+import com.nukkitx.network.util.Preconditions;
+import org.geysermc.connector.utils.MathUtils;
+
+import java.util.Arrays;
+
+/**
+ * Adapted from NukkitX: https://github.com/NukkitX/Nukkit
+ */
+public class Pow2Palette implements Palette {
+
+    /**
+     * Array used to store data
+     */
+    private final int[] words;
+
+    /**
+     * Palette version information
+     */
+    private final PaletteVersion version;
+
+    /**
+     * Number of entries in this palette (<b>not</b> the length of the words array that internally backs this palette)
+     */
+    private final int size;
+
+    Pow2Palette(PaletteVersion version, int size, int[] words) {
+        this.size = size;
+        this.version = version;
+        this.words = words;
+        int expectedWordsLength = MathUtils.ceil((float) size / version.entriesPerWord);
+        if (words.length != expectedWordsLength) {
+            throw new IllegalArgumentException("Invalid length given for storage, got: " + words.length +
+                    " but expected: " + expectedWordsLength);
+        }
+    }
+
+    /**
+     * Sets the entry at the given location to the given value
+     */
+    public void set(int index, int value) {
+        Preconditions.checkElementIndex(index, this.size);
+        Preconditions.checkArgument(value >= 0 && value <= this.version.maxEntryValue, "Invalid value");
+        int bitIndex = index * this.version.bits;
+        int arrayIndex = bitIndex >> 5;
+        int offset = bitIndex & 31;
+        this.words[arrayIndex] = this.words[arrayIndex] & ~(this.version.maxEntryValue << offset) | (value & this.version.maxEntryValue) << offset;
+    }
+
+    /**
+     * Gets the entry at the given index
+     */
+    public int get(int index) {
+        Preconditions.checkElementIndex(index, this.size);
+        int bitIndex = index * this.version.bits;
+        int arrayIndex = bitIndex >> 5;
+        int wordOffset = bitIndex & 31;
+        return this.words[arrayIndex] >>> wordOffset & this.version.maxEntryValue;
+    }
+
+    /**
+     * Gets the long array that is used to store the data in this BitArray. This is useful for sending packet data.
+     */
+    public int size() {
+        return this.size;
+    }
+
+    /**
+     * {@inheritDoc}
+     * @return {@inheritDoc}
+     */
+    @Override
+    public int[] getWords() {
+        return this.words;
+    }
+
+    public PaletteVersion getVersion() {
+        return version;
+    }
+
+    @Override
+    public Palette copy() {
+        return new Pow2Palette(this.version, this.size, Arrays.copyOf(this.words, this.words.length));
+    }
+}