64 lines
1.7 KiB
Java
64 lines
1.7 KiB
Java
package net.minecraft.network;
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import io.netty.buffer.ByteBuf;
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import io.netty.buffer.Unpooled;
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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.CorruptedFrameException;
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import java.util.List;
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import org.jetbrains.annotations.Nullable;
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/**
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* Counterpart to {@link Varint21LengthFieldPrepender}. Decodes each frame ("packet") by first reading its length and then its data.
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*/
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public class Varint21FrameDecoder extends ByteToMessageDecoder {
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private static final int MAX_VARINT21_BYTES = 3;
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private final ByteBuf helperBuf = Unpooled.directBuffer(3);
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@Nullable
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private final BandwidthDebugMonitor monitor;
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public Varint21FrameDecoder(@Nullable BandwidthDebugMonitor monitor) {
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this.monitor = monitor;
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}
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@Override
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protected void handlerRemoved0(ChannelHandlerContext channelHandlerContext) {
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this.helperBuf.release();
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}
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private static boolean copyVarint(ByteBuf in, ByteBuf out) {
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for (int i = 0; i < 3; i++) {
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if (!in.isReadable()) {
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return false;
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}
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byte b = in.readByte();
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out.writeByte(b);
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if (!VarInt.hasContinuationBit(b)) {
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return true;
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}
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}
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throw new CorruptedFrameException("length wider than 21-bit");
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}
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@Override
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protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) {
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byteBuf.markReaderIndex();
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this.helperBuf.clear();
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if (!copyVarint(byteBuf, this.helperBuf)) {
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byteBuf.resetReaderIndex();
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} else {
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int i = VarInt.read(this.helperBuf);
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if (byteBuf.readableBytes() < i) {
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byteBuf.resetReaderIndex();
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} else {
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if (this.monitor != null) {
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this.monitor.onReceive(i + VarInt.getByteSize(i));
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}
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list.add(byteBuf.readBytes(i));
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}
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}
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}
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}
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