From 891be30a28c6dc5a1edf1cb5a3690644cf4ff66e Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Mon, 27 Apr 2015 15:14:01 +0200
Subject: [PATCH] Remove memory copy when extract frame in
 LengthFieldBasedFrameDecoder

Motivation:

We are currently doing a memory cop to extract the frame in LengthFieldBasedFrameDecoder which can be eliminated.

Modifications:

Use buffer.slice(...).retain() to eliminate the memory copy.

Result:

Better performance.
---
 .../io/netty/handler/codec/LengthFieldBasedFrameDecoder.java  | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/codec/src/main/java/io/netty/handler/codec/LengthFieldBasedFrameDecoder.java b/codec/src/main/java/io/netty/handler/codec/LengthFieldBasedFrameDecoder.java
index 2aa95cba71..608ff27f52 100644
--- a/codec/src/main/java/io/netty/handler/codec/LengthFieldBasedFrameDecoder.java
+++ b/codec/src/main/java/io/netty/handler/codec/LengthFieldBasedFrameDecoder.java
@@ -491,9 +491,7 @@ public class LengthFieldBasedFrameDecoder extends ByteToMessageDecoder {
      * is overridden to avoid memory copy.
      */
     protected ByteBuf extractFrame(ChannelHandlerContext ctx, ByteBuf buffer, int index, int length) {
-        ByteBuf frame = ctx.alloc().buffer(length);
-        frame.writeBytes(buffer, index, length);
-        return frame;
+        return buffer.slice(index, length).retain();
     }
 
     private void fail(long frameLength) {