13
0
geforkt von Mirrors/Velocity

Optimize varint frame decoding again

Use ByteProcessor in a controlled matter in one specific case. Performance measurements with my Ryzen 5 3600 indicate a 25-35% improvement in time spent framing incoming packets.
Dieser Commit ist enthalten in:
Andrew Steinborn 2020-05-29 20:52:04 -04:00
Ursprung 9f6d8e1840
Commit b6f1dcc166

Datei anzeigen

@ -1,41 +1,63 @@
package com.velocitypowered.proxy.protocol.netty; package com.velocitypowered.proxy.protocol.netty;
import com.velocitypowered.proxy.protocol.ProtocolUtils; import com.velocitypowered.proxy.util.except.QuietException;
import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder; import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.CorruptedFrameException; import io.netty.util.ByteProcessor;
import java.util.List; import java.util.List;
public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder { public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder {
private static final QuietException BAD_LENGTH_CACHED = new QuietException("Bad packet length");
private final VarintByteDecoder reader = new VarintByteDecoder();
@Override @Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception { protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) {
read_lens: while (in.isReadable()) { while (in.isReadable()) {
int origReaderIndex = in.readerIndex(); int varintEnd = in.forEachByte(reader);
for (int i = 0; i < 3; i++) { if (varintEnd == -1) {
if (!in.isReadable()) {
in.readerIndex(origReaderIndex);
return; return;
} }
byte read = in.readByte(); if (!reader.successfulDecode) {
if (read >= 0) { throw BAD_LENGTH_CACHED;
// Make sure reader index of length buffer is returned to the beginning }
in.readerIndex(origReaderIndex);
int packetLength = ProtocolUtils.readVarInt(in);
if (in.readableBytes() >= packetLength) { int minimumRead = reader.bytesRead + reader.readVarint;
out.add(in.readBytes(packetLength)); if (in.isReadable(minimumRead)) {
continue read_lens; out.add(in.retainedSlice(varintEnd + 1, reader.readVarint));
in.skipBytes(minimumRead);
reader.reset();
} else { } else {
in.readerIndex(origReaderIndex); reader.reset();
return; return;
} }
} }
} }
throw new CorruptedFrameException("VarInt too big"); private static class VarintByteDecoder implements ByteProcessor {
private int readVarint;
private int bytesRead;
private boolean successfulDecode;
@Override
public boolean process(byte k) {
readVarint |= (k & 0x7F) << bytesRead++ * 7;
if (bytesRead > 3) {
return false;
}
if ((k & 0x80) != 128) {
successfulDecode = true;
return false;
}
return true;
}
void reset() {
readVarint = 0;
bytesRead = 0;
successfulDecode = false;
} }
} }
} }