Reduce amount of memcpy within proxy pipeline.

proxy/src/main/java/net/md_5/bungee/compress/PacketDecompressor.java

@@ -1,13 +1,14 @@
 package net.md_5.bungee.compress;
 
+import com.google.common.base.Preconditions;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
-import io.netty.handler.codec.ByteToMessageDecoder;
+import io.netty.handler.codec.MessageToMessageDecoder;
 import java.util.List;
 import net.md_5.bungee.jni.zlib.BungeeZlib;
 import net.md_5.bungee.protocol.DefinedPacket;
 
-public class PacketDecompressor extends ByteToMessageDecoder
+public class PacketDecompressor extends MessageToMessageDecoder<ByteBuf>
 {
 
     private final BungeeZlib zlib = CompressFactory.zlib.newInstance();
@@ -19,7 +20,7 @@ public class PacketDecompressor extends ByteToMessageDecoder
     }
 
     @Override
-    public void handlerRemoved0(ChannelHandlerContext ctx) throws Exception
+    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception
     {
         zlib.free();
     }
@@ -27,22 +28,29 @@ public class PacketDecompressor extends ByteToMessageDecoder
     @Override
     protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception
     {
-        if ( in.readableBytes() == 0 )
-        {
-            return;
-        }
-
         int size = DefinedPacket.readVarInt( in );
         if ( size == 0 )
         {
-            out.add( in.copy() );
-            in.readerIndex( in.writerIndex() );
+            out.add( in.slice().retain() );
+            in.skipBytes( in.readableBytes() );
         } else
         {
             ByteBuf decompressed = ctx.alloc().directBuffer();
-            zlib.process( in, decompressed );
 
-            out.add( decompressed );
+            try
+            {
+                zlib.process( in, decompressed );
+                Preconditions.checkState( decompressed.readableBytes() == size, "Decompressed packet size mismatch" );
+
+                out.add( decompressed );
+                decompressed = null;
+            } finally
+            {
+                if ( decompressed != null )
+                {
+                    decompressed.release();
+                }
+            }
         }
     }
 }