src/main/java/us/myles/ViaVersion/util/PacketUtil.java - minecraft/viaversion - Rivoreo Source Code Repositories

 package us.myles.ViaVersion.util;

 import com.google.common.base.Charsets;
 import com.google.common.base.Preconditions;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufInputStream;
 import io.netty.buffer.ByteBufOutputStream;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.handler.codec.MessageToByteEncoder;
 import org.spacehq.opennbt.NBTIO;
 import org.spacehq.opennbt.tag.builtin.CompoundTag;

 import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;

 public class PacketUtil {
     private static Method DECODE_METHOD;
     private static Method ENCODE_METHOD;

     static {
         try {
             DECODE_METHOD = ByteToMessageDecoder.class.getDeclaredMethod("decode", ChannelHandlerContext.class, ByteBuf.class, List.class);
             DECODE_METHOD.setAccessible(true);
         } catch (NoSuchMethodException e) {
             e.printStackTrace();
             System.out.println("Netty issue?");
         }
         try {
             ENCODE_METHOD = MessageToByteEncoder.class.getDeclaredMethod("encode", ChannelHandlerContext.class, Object.class, ByteBuf.class);
             ENCODE_METHOD.setAccessible(true);
         } catch (NoSuchMethodException e) {
             e.printStackTrace();
             System.out.println("Netty issue?");
         }
     }

     public static CompoundTag readNBT(ByteBuf input) throws IOException {
         // Default client is limited to 2097152 bytes. (2.09mb)
         Preconditions.checkArgument(input.readableBytes() <= 2097152, "Cannot read NBT (got %s bytes)", input.readableBytes());

         int readerIndex = input.readerIndex();
         byte b = input.readByte();
         if (b == 0) {
             return null;
         } else {
             input.readerIndex(readerIndex);
             ByteBufInputStream bytebufStream = new ByteBufInputStream(input);
             DataInputStream dataInputStream = new DataInputStream(bytebufStream);
             try {
                 return (CompoundTag) NBTIO.readTag(dataInputStream);
             } finally {
                 dataInputStream.close();
             }
         }
     }

     public static void writeNBT(ByteBuf output, CompoundTag tag) throws IOException {
         if (tag == null) {
             output.writeByte(0);
         } else {
             ByteBufOutputStream bytebufStream = new ByteBufOutputStream(output);
             DataOutputStream dataOutputStream = new DataOutputStream(bytebufStream);

             NBTIO.writeTag(dataOutputStream, tag);

             dataOutputStream.close();
         }
     }

     public static List<Object> callDecode(ByteToMessageDecoder decoder, ChannelHandlerContext ctx, Object input) throws InvocationTargetException {
         List<Object> output = new ArrayList<>();
         try {
             PacketUtil.DECODE_METHOD.invoke(decoder, ctx, input, output);
         } catch (IllegalAccessException e) {
             e.printStackTrace();
         }
         return output;
     }

     public static void callEncode(MessageToByteEncoder encoder, ChannelHandlerContext ctx, Object msg, ByteBuf output) throws InvocationTargetException {
         try {
             PacketUtil.ENCODE_METHOD.invoke(encoder, ctx, msg, output);
         } catch (IllegalAccessException e) {
             e.printStackTrace();
         }
     }

     /* I take no credit, these are taken from BungeeCord */
     // https://github.com/SpigotMC/BungeeCord/blob/master/protocol/src/main/java/net/md_5/bungee/protocol/DefinedPacket.java
     public static void writeString(String s, ByteBuf buf) {
         Preconditions.checkArgument(s.length() <= Short.MAX_VALUE, "Cannot send string longer than Short.MAX_VALUE (got %s characters)", s.length());

         byte[] b = s.getBytes(Charsets.UTF_8);
         writeVarInt(b.length, buf);
         buf.writeBytes(b);
     }

     public static String readString(ByteBuf buf) {
         int len = readVarInt(buf);
         Preconditions.checkArgument(len <= Short.MAX_VALUE, "Cannot receive string longer than Short.MAX_VALUE (got %s characters)", len);

         byte[] b = new byte[len];
         buf.readBytes(b);

         return new String(b, Charsets.UTF_8);
     }

     public static void writeArrayLegacy(byte[] b, ByteBuf buf, boolean allowExtended) {
         // (Integer.MAX_VALUE & 0x1FFF9A ) = 2097050 - Forge's current upper limit
         if (allowExtended) {
             Preconditions.checkArgument(b.length <= (Integer.MAX_VALUE & 0x1FFF9A), "Cannot send array longer than 2097050 (got %s bytes)", b.length);
         } else {
             Preconditions.checkArgument(b.length <= Short.MAX_VALUE, "Cannot send array longer than Short.MAX_VALUE (got %s bytes)", b.length);
         }
         // Write a 2 or 3 byte number that represents the length of the packet. (3 byte "shorts" for Forge only)
         // No vanilla packet should give a 3 byte packet, this method will still retain vanilla behaviour.
         writeVarShort(buf, b.length);
         buf.writeBytes(b);
     }

     public static byte[] readArrayLegacy(ByteBuf buf) {
         // Read in a 2 or 3 byte number that represents the length of the packet. (3 byte "shorts" for Forge only)
         // No vanilla packet should give a 3 byte packet, this method will still retain vanilla behaviour.
         int len = readVarShort(buf);

         // (Integer.MAX_VALUE & 0x1FFF9A ) = 2097050 - Forge's current upper limit
         Preconditions.checkArgument(len <= (Integer.MAX_VALUE & 0x1FFF9A), "Cannot receive array longer than 2097050 (got %s bytes)", len);

         byte[] ret = new byte[len];
         buf.readBytes(ret);
         return ret;
     }

     public static void writeArray(byte[] b, ByteBuf buf) {
         writeVarInt(b.length, buf);
         buf.writeBytes(b);
     }

     public static byte[] readArray(ByteBuf buf) {
         byte[] ret = new byte[readVarInt(buf)];
         buf.readBytes(ret);
         return ret;
     }

     public static void writeStringArray(List<String> s, ByteBuf buf) {
         writeVarInt(s.size(), buf);
         for (String str : s) {
             writeString(str, buf);
         }
     }

     public static List<String> readStringArray(ByteBuf buf) {
         int len = readVarInt(buf);
         List<String> ret = new ArrayList<>(len);
         for (int i = 0; i < len; i++) {
             ret.add(readString(buf));
         }
         return ret;
     }

     public static int readVarInt(ByteBuf input) {
         return readVarInt(input, 5);
     }

     public static int readVarInt(ByteBuf input, int maxBytes) {
         int out = 0;
         int bytes = 0;
         byte in;
         while (true) {
             in = input.readByte();

             out |= (in & 0x7F) << (bytes++ * 7);

             if (bytes > maxBytes) {
                 throw new RuntimeException("VarInt too big");
             }

             if ((in & 0x80) != 0x80) {
                 break;
             }
         }

         return out;
     }

     public static void writeVarInt(int value, ByteBuf output) {
         int part;
         while (true) {
             part = value & 0x7F;

             value >>>= 7;
             if (value != 0) {
                 part |= 0x80;
             }

             output.writeByte(part);

             if (value == 0) {
                 break;
             }
         }
     }

     public static void writeVarIntArray(List<Integer> integers, ByteBuf output) {
         writeVarInt(integers.size(), output);
         for (Integer i : integers) {
             writeVarInt(i, output);
         }
     }

     public static int readVarShort(ByteBuf buf) {
         int low = buf.readUnsignedShort();
         int high = 0;
         if ((low & 0x8000) != 0) {
             low = low & 0x7FFF;
             high = buf.readUnsignedByte();
         }
         return ((high & 0xFF) << 15) | low;
     }

     public static void writeVarShort(ByteBuf buf, int toWrite) {
         int low = toWrite & 0x7FFF;
         int high = (toWrite & 0x7F8000) >> 15;
         if (high != 0) {
             low = low | 0x8000;
         }
         buf.writeShort(low);
         if (high != 0) {
             buf.writeByte(high);
         }
     }

     public static void writeUUID(UUID value, ByteBuf output) {
         output.writeLong(value.getMostSignificantBits());
         output.writeLong(value.getLeastSignificantBits());
     }

     public static UUID readUUID(ByteBuf input) {
         return new UUID(input.readLong(), input.readLong());
     }

     public static void writeLongs(long[] data, ByteBuf output) {
         for (long aData : data) {
             output.writeLong(aData);
         }
     }

     public static long[] readLongs(int amount, ByteBuf output) {
         long data[] = new long[amount];
         for (int index = 0; index < amount; index++) {
             data[index] = output.readLong();
         }

         return data;
     }

     public static long[] readBlockPosition(ByteBuf buf) {
         long val = buf.readLong();
         long x = (val >> 38); // signed
         long y = (val >> 26) & 0xfff; // unsigned
         // this shifting madness is used to preserve sign
         long z = (val << 38) >> 38; // signed
         return new long[]{x, y, z};
     }

     public static void writeBlockPosition(ByteBuf buf, long x, long y, long z) {
         buf.writeLong(((x & 0x3ffffff) << 38) | ((y & 0xfff) << 26) | (z & 0x3ffffff));
     }

     public static int[] readVarInts(int amount, ByteBuf input) {
         int data[] = new int[amount];
         for (int index = 0; index < amount; index++) {
             data[index] = PacketUtil.readVarInt(input);
         }

         return data;
     }

     public static boolean containsCause(Throwable t, Class<? extends Throwable> c) {
         while (t != null) {
             t = t.getCause();
             if (t != null)
                 if (c.isAssignableFrom(t.getClass())) return true;
         }
         return false;
     }
 }
	package us.myles.ViaVersion.util;

	import com.google.common.base.Charsets;
	import com.google.common.base.Preconditions;
	import io.netty.buffer.ByteBuf;
	import io.netty.buffer.ByteBufInputStream;
	import io.netty.buffer.ByteBufOutputStream;
	import io.netty.channel.ChannelHandlerContext;
	import io.netty.handler.codec.ByteToMessageDecoder;
	import io.netty.handler.codec.MessageToByteEncoder;
	import org.spacehq.opennbt.NBTIO;
	import org.spacehq.opennbt.tag.builtin.CompoundTag;

	import java.io.DataInputStream;
	import java.io.DataOutputStream;
	import java.io.IOException;
	import java.lang.reflect.InvocationTargetException;
	import java.lang.reflect.Method;
	import java.util.ArrayList;
	import java.util.List;
	import java.util.UUID;

	public class PacketUtil {
	private static Method DECODE_METHOD;
	private static Method ENCODE_METHOD;

	static {
	try {
	DECODE_METHOD = ByteToMessageDecoder.class.getDeclaredMethod("decode", ChannelHandlerContext.class, ByteBuf.class, List.class);
	DECODE_METHOD.setAccessible(true);
	} catch (NoSuchMethodException e) {
	e.printStackTrace();
	System.out.println("Netty issue?");
	}
	try {
	ENCODE_METHOD = MessageToByteEncoder.class.getDeclaredMethod("encode", ChannelHandlerContext.class, Object.class, ByteBuf.class);
	ENCODE_METHOD.setAccessible(true);
	} catch (NoSuchMethodException e) {
	e.printStackTrace();
	System.out.println("Netty issue?");
	}
	}

	public static CompoundTag readNBT(ByteBuf input) throws IOException {
	// Default client is limited to 2097152 bytes. (2.09mb)
	Preconditions.checkArgument(input.readableBytes() <= 2097152, "Cannot read NBT (got %s bytes)", input.readableBytes());

	int readerIndex = input.readerIndex();
	byte b = input.readByte();
	if (b == 0) {
	return null;
	} else {
	input.readerIndex(readerIndex);
	ByteBufInputStream bytebufStream = new ByteBufInputStream(input);
	DataInputStream dataInputStream = new DataInputStream(bytebufStream);
	try {
	return (CompoundTag) NBTIO.readTag(dataInputStream);
	} finally {
	dataInputStream.close();
	}
	}
	}

	public static void writeNBT(ByteBuf output, CompoundTag tag) throws IOException {
	if (tag == null) {
	output.writeByte(0);
	} else {
	ByteBufOutputStream bytebufStream = new ByteBufOutputStream(output);
	DataOutputStream dataOutputStream = new DataOutputStream(bytebufStream);

	NBTIO.writeTag(dataOutputStream, tag);

	dataOutputStream.close();
	}
	}

	public static List<Object> callDecode(ByteToMessageDecoder decoder, ChannelHandlerContext ctx, Object input) throws InvocationTargetException {
	List<Object> output = new ArrayList<>();
	try {
	PacketUtil.DECODE_METHOD.invoke(decoder, ctx, input, output);
	} catch (IllegalAccessException e) {
	e.printStackTrace();
	}
	return output;
	}

	public static void callEncode(MessageToByteEncoder encoder, ChannelHandlerContext ctx, Object msg, ByteBuf output) throws InvocationTargetException {
	try {
	PacketUtil.ENCODE_METHOD.invoke(encoder, ctx, msg, output);
	} catch (IllegalAccessException e) {
	e.printStackTrace();
	}
	}

	/* I take no credit, these are taken from BungeeCord */
	// https://github.com/SpigotMC/BungeeCord/blob/master/protocol/src/main/java/net/md_5/bungee/protocol/DefinedPacket.java
	public static void writeString(String s, ByteBuf buf) {
	Preconditions.checkArgument(s.length() <= Short.MAX_VALUE, "Cannot send string longer than Short.MAX_VALUE (got %s characters)", s.length());

	byte[] b = s.getBytes(Charsets.UTF_8);
	writeVarInt(b.length, buf);
	buf.writeBytes(b);
	}

	public static String readString(ByteBuf buf) {
	int len = readVarInt(buf);
	Preconditions.checkArgument(len <= Short.MAX_VALUE, "Cannot receive string longer than Short.MAX_VALUE (got %s characters)", len);

	byte[] b = new byte[len];
	buf.readBytes(b);

	return new String(b, Charsets.UTF_8);
	}

	public static void writeArrayLegacy(byte[] b, ByteBuf buf, boolean allowExtended) {
	// (Integer.MAX_VALUE & 0x1FFF9A ) = 2097050 - Forge's current upper limit
	if (allowExtended) {
	Preconditions.checkArgument(b.length <= (Integer.MAX_VALUE & 0x1FFF9A), "Cannot send array longer than 2097050 (got %s bytes)", b.length);
	} else {
	Preconditions.checkArgument(b.length <= Short.MAX_VALUE, "Cannot send array longer than Short.MAX_VALUE (got %s bytes)", b.length);
	}
	// Write a 2 or 3 byte number that represents the length of the packet. (3 byte "shorts" for Forge only)
	// No vanilla packet should give a 3 byte packet, this method will still retain vanilla behaviour.
	writeVarShort(buf, b.length);
	buf.writeBytes(b);
	}

	public static byte[] readArrayLegacy(ByteBuf buf) {
	// Read in a 2 or 3 byte number that represents the length of the packet. (3 byte "shorts" for Forge only)
	// No vanilla packet should give a 3 byte packet, this method will still retain vanilla behaviour.
	int len = readVarShort(buf);

	// (Integer.MAX_VALUE & 0x1FFF9A ) = 2097050 - Forge's current upper limit
	Preconditions.checkArgument(len <= (Integer.MAX_VALUE & 0x1FFF9A), "Cannot receive array longer than 2097050 (got %s bytes)", len);

	byte[] ret = new byte[len];
	buf.readBytes(ret);
	return ret;
	}

	public static void writeArray(byte[] b, ByteBuf buf) {
	writeVarInt(b.length, buf);
	buf.writeBytes(b);
	}

	public static byte[] readArray(ByteBuf buf) {
	byte[] ret = new byte[readVarInt(buf)];
	buf.readBytes(ret);
	return ret;
	}

	public static void writeStringArray(List<String> s, ByteBuf buf) {
	writeVarInt(s.size(), buf);
	for (String str : s) {
	writeString(str, buf);
	}
	}

	public static List<String> readStringArray(ByteBuf buf) {
	int len = readVarInt(buf);
	List<String> ret = new ArrayList<>(len);
	for (int i = 0; i < len; i++) {
	ret.add(readString(buf));
	}
	return ret;
	}

	public static int readVarInt(ByteBuf input) {
	return readVarInt(input, 5);
	}

	public static int readVarInt(ByteBuf input, int maxBytes) {
	int out = 0;
	int bytes = 0;
	byte in;
	while (true) {
	in = input.readByte();

	out \|= (in & 0x7F) << (bytes++ * 7);

	if (bytes > maxBytes) {
	throw new RuntimeException("VarInt too big");
	}

	if ((in & 0x80) != 0x80) {
	break;
	}
	}

	return out;
	}

	public static void writeVarInt(int value, ByteBuf output) {
	int part;
	while (true) {
	part = value & 0x7F;

	value >>>= 7;
	if (value != 0) {
	part \|= 0x80;
	}

	output.writeByte(part);

	if (value == 0) {
	break;
	}
	}
	}

	public static void writeVarIntArray(List<Integer> integers, ByteBuf output) {
	writeVarInt(integers.size(), output);
	for (Integer i : integers) {
	writeVarInt(i, output);
	}
	}

	public static int readVarShort(ByteBuf buf) {
	int low = buf.readUnsignedShort();
	int high = 0;
	if ((low & 0x8000) != 0) {
	low = low & 0x7FFF;
	high = buf.readUnsignedByte();
	}
	return ((high & 0xFF) << 15) \| low;
	}

	public static void writeVarShort(ByteBuf buf, int toWrite) {
	int low = toWrite & 0x7FFF;
	int high = (toWrite & 0x7F8000) >> 15;
	if (high != 0) {
	low = low \| 0x8000;
	}
	buf.writeShort(low);
	if (high != 0) {
	buf.writeByte(high);
	}
	}

	public static void writeUUID(UUID value, ByteBuf output) {
	output.writeLong(value.getMostSignificantBits());
	output.writeLong(value.getLeastSignificantBits());
	}

	public static UUID readUUID(ByteBuf input) {
	return new UUID(input.readLong(), input.readLong());
	}

	public static void writeLongs(long[] data, ByteBuf output) {
	for (long aData : data) {
	output.writeLong(aData);
	}
	}

	public static long[] readLongs(int amount, ByteBuf output) {
	long data[] = new long[amount];
	for (int index = 0; index < amount; index++) {
	data[index] = output.readLong();
	}

	return data;
	}

	public static long[] readBlockPosition(ByteBuf buf) {
	long val = buf.readLong();
	long x = (val >> 38); // signed
	long y = (val >> 26) & 0xfff; // unsigned
	// this shifting madness is used to preserve sign
	long z = (val << 38) >> 38; // signed
	return new long[]{x, y, z};
	}

	public static void writeBlockPosition(ByteBuf buf, long x, long y, long z) {
	buf.writeLong(((x & 0x3ffffff) << 38) \| ((y & 0xfff) << 26) \| (z & 0x3ffffff));
	}

	public static int[] readVarInts(int amount, ByteBuf input) {
	int data[] = new int[amount];
	for (int index = 0; index < amount; index++) {
	data[index] = PacketUtil.readVarInt(input);
	}

	return data;
	}

	public static boolean containsCause(Throwable t, Class<? extends Throwable> c) {
	while (t != null) {
	t = t.getCause();
	if (t != null)
	if (c.isAssignableFrom(t.getClass())) return true;
	}
	return false;
	}
	}