From d62c1311fb178dc80c85e5816b16f4eae4b68108 Mon Sep 17 00:00:00 2001
From: "PSp..om" <PSpeed42@gmail.com>
Date: Fri, 5 Aug 2011 06:46:56 +0000
Subject: [PATCH] Fixed a long-standing but well hidden bug in message
 protocol.  In the wild, I've only seen this crop up in really really odd
 circumstances.  As it turns out, the throughput tests eventually trigger this
 when testing TCP.  I've lost sleep over wondering when this was going to bite
 for real so I'm glad to have what is essentially the last known bug in
 message transfer fixed. This change handles the case where so far only one
 byte of the two byte message size has been read from the network.  Rare, but
 it can happen.

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@7976 75d07b2b-3a1a-0410-a2c5-0572b91ccdca
---
 .../jme3/network/base/MessageProtocol.java    | 39 +++++++++++++++----
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/engine/src/networking/com/jme3/network/base/MessageProtocol.java b/engine/src/networking/com/jme3/network/base/MessageProtocol.java
index 515e6a356..b42d4746f 100644
--- a/engine/src/networking/com/jme3/network/base/MessageProtocol.java
+++ b/engine/src/networking/com/jme3/network/base/MessageProtocol.java
@@ -58,6 +58,7 @@ public class MessageProtocol
     private LinkedList<Message> messages = new LinkedList<Message>();
     private ByteBuffer current;
     private int size;
+    private Byte carry;
  
     /**
      *  Converts a message to a ByteBuffer using the Serializer
@@ -108,15 +109,39 @@ public class MessageProtocol
         // push the data from the buffer into as
         // many messages as we can
         while( buffer.remaining() > 0 ) {
-                
+
             if( current == null ) {
-                // We are not currently reading an object so
-                // grab the size.
-                // Note: this is somewhat limiting... int would
-                // be better.
-                size = buffer.getShort();
+
+                // If we have a left over carry then we need to
+                // do manual processing to get the short value
+                if( carry != null ) {
+                    byte high = carry;
+                    byte low = buffer.get();
+                    
+                    size = (high & 0xff) << 8 | (low & 0xff);
+                    carry = null;
+                }
+                else if( buffer.remaining() < 2 ) {
+                    // It's possible that the supplied buffer only has one
+                    // byte in it... and in that case we will get an underflow
+                    // when attempting to read the short below.
+                    
+                    // It has to be 1 or we'd never get here... but one
+                    // isn't enough so we stash it away.
+                    carry = buffer.get();
+                    break;
+                } else {
+                    // We are not currently reading an object so
+                    // grab the size.
+                    // Note: this is somewhat limiting... int would
+                    // be better.
+                    size = buffer.getShort();
+                }               
+ 
+                // Allocate the buffer into which we'll feed the
+                // data as we get it               
                 current = ByteBuffer.allocate(size);
-            }
+            } 
 
             if( current.remaining() <= buffer.remaining() ) {
                 // We have at least one complete object so