From e07f7c75c95275affb07d159cbc2df5dd7d7cfe2 Mon Sep 17 00:00:00 2001
From: lidgren <lidgren@users.noreply.github.com>
Date: Fri, 20 Jan 2012 09:52:19 +0000
Subject: [PATCH] NetOutgoingMessage.Write(float) optimized to avoid memory
 allocation

---
 Lidgren.Network/NetOutgoingMessage.Write.cs | 27 +++++++++++++++------
 UnitTests/ReadWriteTests.cs                 |  4 +--
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/Lidgren.Network/NetOutgoingMessage.Write.cs b/Lidgren.Network/NetOutgoingMessage.Write.cs
index e94d551..e2f88fc 100644
--- a/Lidgren.Network/NetOutgoingMessage.Write.cs
+++ b/Lidgren.Network/NetOutgoingMessage.Write.cs
@@ -21,9 +21,21 @@ using System.Collections.Generic;
 using System.Net;
 using System.Reflection;
 using System.Text;
+using System.Runtime.InteropServices;
 
 namespace Lidgren.Network
 {
+	[StructLayout(LayoutKind.Explicit)]
+	public struct SingleUIntUnion
+	{
+		[FieldOffset(0)]
+		public float SingleValue;
+
+		[FieldOffset(0)]
+		[CLSCompliant(false)]
+		public uint UIntValue;
+	}
+
 	public sealed partial class NetOutgoingMessage
 	{
 		private const int c_overAllocateAmount = 4;
@@ -386,17 +398,16 @@ namespace Lidgren.Network
 		/// </summary>
 		public void Write(float source)
 		{
-			byte[] val = BitConverter.GetBytes(source);
+			// Use union to avoid BitConverter.GetBytes() which allocates memory on the heap
+			SingleUIntUnion su;
+			su.UIntValue = 0; // must initialize every member of the union to avoid warning
+			su.SingleValue = source;
+
 #if BIGENDIAN
 			// swap byte order
-			byte tmp = val[3];
-			val[3] = val[0];
-			val[0] = tmp;
-			tmp = val[2];
-			val[2] = val[1];
-			val[1] = tmp;
+			su.UIntValue = NetUtility.SwapByteOrder(su.UIntValue);
 #endif
-			Write(val);
+			Write(su.UIntValue);
 		}
 #endif
 
diff --git a/UnitTests/ReadWriteTests.cs b/UnitTests/ReadWriteTests.cs
index cec9961..1e3a705 100644
--- a/UnitTests/ReadWriteTests.cs
+++ b/UnitTests/ReadWriteTests.cs
@@ -49,7 +49,7 @@ namespace UnitTests
 
 			int bcnt = 0;
 
-			msg.Write(45.0f);
+			msg.Write(567845.0f);
 			msg.WriteVariableInt32(2115998022);
 			msg.Write(46.0);
 			bcnt += msg.WriteVariableInt32(-47);
@@ -94,7 +94,7 @@ namespace UnitTests
 			bdr.Append(inc.ReadVariableUInt32());
 			bdr.Append(inc.ReadVariableInt64());
 
-			if (bdr.ToString().Equals("False-342duke of earl4344True45211599802246-4747000048-49"))
+			if (bdr.ToString().Equals("False-342duke of earl4344True567845211599802246-4747000048-49"))
 				Console.WriteLine("Read/write tests OK");
 			else
 				throw new NetException("Read/write tests FAILED!");