93 lines
2.9 KiB
Java
93 lines
2.9 KiB
Java
package net.minecraft.network;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.handler.codec.ByteToMessageDecoder;
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import io.netty.handler.codec.DecoderException;
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import java.nio.ByteBuffer;
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import java.util.List;
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import java.util.zip.DataFormatException;
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import java.util.zip.Inflater;
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/**
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* Handles decompression of network traffic.
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*
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* @see Connection#setupCompression
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*/
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public class CompressionDecoder extends ByteToMessageDecoder {
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public static final int MAXIMUM_COMPRESSED_LENGTH = 2097152;
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public static final int MAXIMUM_UNCOMPRESSED_LENGTH = 8388608;
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private final Inflater inflater;
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private int threshold;
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private boolean validateDecompressed;
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public CompressionDecoder(int threshold, boolean validateDecompressed) {
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this.threshold = threshold;
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this.validateDecompressed = validateDecompressed;
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this.inflater = new Inflater();
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}
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@Override
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protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) throws Exception {
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if (byteBuf.readableBytes() != 0) {
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int i = VarInt.read(byteBuf);
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if (i == 0) {
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list.add(byteBuf.readBytes(byteBuf.readableBytes()));
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} else {
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if (this.validateDecompressed) {
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if (i < this.threshold) {
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throw new DecoderException("Badly compressed packet - size of " + i + " is below server threshold of " + this.threshold);
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}
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if (i > 8388608) {
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throw new DecoderException("Badly compressed packet - size of " + i + " is larger than protocol maximum of 8388608");
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}
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}
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this.setupInflaterInput(byteBuf);
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ByteBuf byteBuf2 = this.inflate(channelHandlerContext, i);
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this.inflater.reset();
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list.add(byteBuf2);
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}
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}
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}
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private void setupInflaterInput(ByteBuf buffer) {
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ByteBuffer byteBuffer;
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if (buffer.nioBufferCount() > 0) {
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byteBuffer = buffer.nioBuffer();
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buffer.skipBytes(buffer.readableBytes());
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} else {
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byteBuffer = ByteBuffer.allocateDirect(buffer.readableBytes());
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buffer.readBytes(byteBuffer);
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byteBuffer.flip();
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}
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this.inflater.setInput(byteBuffer);
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}
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private ByteBuf inflate(ChannelHandlerContext context, int size) throws DataFormatException {
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ByteBuf byteBuf = context.alloc().directBuffer(size);
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try {
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ByteBuffer byteBuffer = byteBuf.internalNioBuffer(0, size);
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int i = byteBuffer.position();
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this.inflater.inflate(byteBuffer);
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int j = byteBuffer.position() - i;
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if (j != size) {
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throw new DecoderException("Badly compressed packet - actual length of uncompressed payload " + j + " is does not match declared size " + size);
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} else {
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byteBuf.writerIndex(byteBuf.writerIndex() + j);
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return byteBuf;
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}
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} catch (Exception var7) {
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byteBuf.release();
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throw var7;
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}
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}
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public void setThreshold(int threshold, boolean validateDecompressed) {
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this.threshold = threshold;
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this.validateDecompressed = validateDecompressed;
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}
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}
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