Added data caching for networking

gamemode/engine/lib/server/sv_networking.lua

@@ -0,0 +1,56 @@
+--    __           _        _______        _      __   
+--   / /     /\   | |      |__   __|      | |     \ \  
+--  / /     /  \  | |_ __ ___ | | ___  ___| |__    \ \ 
+-- < <     / /\ \ | | '_ ` _ \| |/ _ \/ __| '_ \    > >
+--  \ \   / ____ \| | | | | | | |  __/ (__| | | |  / / 
+--   \_\ /_/    \_\_|_| |_| |_|_|\___|\___|_| |_| /_/  
+
+Quantum.Net = {}
+util.AddNetworkString( "quantum_menu_net" )
+util.AddNetworkString( "quantum_menu_button_net" )
+
+local function CacheDatatableMethod( id, datatable, ply )
+	if( ply.cache == nil ) then ply.cache = {} end 
+
+	if( ply.cache[id] == nil ) then -- if this is the first time then create a cache record
+		ply.cache[id] = {
+			cache = datatable
+			-- won't be defining the count here
+		} 
+	end 
+
+	if( ply.cache[id].count == nil ) then ply.cache[id].count = 1 else ply.cache[id].count = ply.cache[id].count + 1 end -- keep count of how many times we have cached this datatable
+
+	if( ply.cache[id].count > 1 ) then -- dont want to filter out data if this is the first time.
+		for k, v in pairs( datatable ) do -- loop through the datatable
+			for k2, v2 in pairs( table.GetKeys( ply.cache[id].cache ) ) do -- check each key with each key from the record cache
+				if( tostring(k) == tostring(v2) ) then -- check if the keys are the same
+					if( v == ply.cache[id].cache[tostring(v2)] ) then -- check if the value/contents are the same
+						datatable[k] = nil -- if so then remove the key from the datatable
+					else -- if the key's value has changed we dont remove it since the client needs to know about it
+						ply.cache[id].cache[tostring(v2)] = v -- and then update the cache so we know about it next time
+					end
+				end
+			end
+		end
+	end
+	datatable.id = id -- give it the id so that the client side could handle it
+	-- Always give the id since it is highly "valuable".
+	-- Don't want the client mixing up the NPC, which this caching system could do if not handled correctly.
+	return datatable
+end
+
+local function SendDatatableToClient( client, dt, type )
+	local datatable = CacheDatatableMethod( type, dt, client ) -- before we actually send the stuff, cache it and remove unneeded stuff
+	net.Start( "quantum_menu_net" )
+		if( table.Count( datatable ) > 0 ) then -- if it's empty just dont send it because we will save 8 bits 
+			net.WriteTable( datatable ) -- send the data to the player
+		end
+	net.Send( client )
+end
+
+
+net.Receive( "quantum_menu_button_net", function( len, pl )
+    local funcid = net.ReadString()
+    local args = net.ReadTable()
+end)