Added original SDK code for Alien Swarm.

public/inetmessage.h

@@ -0,0 +1,48 @@
+//========= Copyright <20> 1996-2005, Valve Corporation, All rights reserved. ============//
+//
+// Purpose: INetMessage interface
+//
+// $NoKeywords: $
+//=============================================================================//
+
+#ifndef INETMESSAGE_H
+#define INETMESSAGE_H
+
+#include "tier1/bitbuf.h"
+
+class INetMsgHandler;
+class INetMessage;
+class INetChannel;
+
+// typedef bool (INetMsgHandler::*PROCESSFUNCPTR)(INetMessage*);
+// #define CASTPROCPTR( fn ) static_cast <bool (INetMsgHandler::*)(INetMessage*)> (fn)
+
+class INetMessage
+{
+public:
+	virtual	~INetMessage() {};
+
+	// Use these to setup who can hear whose voice.
+	// Pass in client indices (which are their ent indices - 1).
+	
+	virtual void	SetNetChannel(INetChannel * netchan) = 0; // netchannel this message is from/for
+	virtual void	SetReliable( bool state ) = 0;	// set to true if it's a reliable message
+	
+	virtual bool	Process( void ) = 0; // calls the recently set handler to process this message
+	
+	virtual	bool	ReadFromBuffer( bf_read &buffer ) = 0; // returns true if parsing was OK
+	virtual	bool	WriteToBuffer( bf_write &buffer ) = 0;	// returns true if writing was OK
+		
+	virtual bool	IsReliable( void ) const = 0;  // true, if message needs reliable handling
+	
+	virtual int				GetType( void ) const = 0; // returns module specific header tag eg svc_serverinfo
+	virtual int				GetGroup( void ) const = 0;	// returns net message group of this message
+	virtual const char		*GetName( void ) const = 0;	// returns network message name, eg "svc_serverinfo"
+	virtual INetChannel		*GetNetChannel( void ) const = 0;
+	virtual const char		*ToString( void ) const = 0; // returns a human readable string about message content
+	virtual size_t			GetSize() const = 0;
+};
+
+
+#endif
+