feat: XOR encoding

sourcemap.json

@@ -1 +1 @@
-{"name":"warp","className":"ModuleScript","filePaths":["src/init.luau","default.project.json"],"children":[{"name":"Client","className":"ModuleScript","filePaths":["src/Client/init.luau"]},{"name":"Replication","className":"ModuleScript","filePaths":["src/Replication/init.luau"]},{"name":"Server","className":"ModuleScript","filePaths":["src/Server/init.luau"]},{"name":"Util","className":"Folder","children":[{"name":"Buffer","className":"ModuleScript","filePaths":["src/Util/Buffer/init.luau"]},{"name":"Identifier","className":"ModuleScript","filePaths":["src/Util/Identifier.luau"]},{"name":"Thread","className":"ModuleScript","filePaths":["src/Util/Thread.luau"]}]}]}
+{"name":"warp","className":"ModuleScript","filePaths":["src/init.luau","default.project.json"],"children":[{"name":"Client","className":"ModuleScript","filePaths":["src/Client/init.luau"]},{"name":"Replication","className":"ModuleScript","filePaths":["src/Replication/init.luau"]},{"name":"Server","className":"ModuleScript","filePaths":["src/Server/init.luau"]},{"name":"Util","className":"Folder","children":[{"name":"Buffer","className":"ModuleScript","filePaths":["src/Util/Buffer/init.luau"]},{"name":"Identifier","className":"ModuleScript","filePaths":["src/Util/Identifier.luau"]},{"name":"Thread","className":"ModuleScript","filePaths":["src/Util/Thread.luau"]},{"name":"Xor","className":"ModuleScript","filePaths":["src/Util/Xor.luau"]}]}]}

src/Client/init.luau

@@ -3,10 +3,12 @@
 --@EternityDev
 local Client = {}
 
-local RunService = game:GetService("RunService")
 local Thread = require("./Util/Thread")
 local Buffer = require("./Util/Buffer")
 local Replication = require("./Replication")
+local Xor = require("./Util/Xor")
+
+local RunService = game:GetService("RunService")
 local Event: RemoteEvent = script.Parent:WaitForChild("Event")
 local UnreliableEvent: UnreliableRemoteEvent = script.Parent:WaitForChild("UnreliableEvent")
 local deltaT: number, cycle: number = 0, 1 / 61
@@ -26,6 +28,7 @@ local queueUnreliableEvent: { { any } } = {}
 local eventListeners: { [number]: { Event } } = {}
 local eventSchemas: { [number]: Buffer.SchemaType } = {}
 
+local lastDelta: { [number]: { any } } = {}
 local pendingInvokes: { [string]: thread } = {}
 local invokeId = 0
 
@@ -165,13 +168,12 @@ end
 
 if RunService:IsClient() then
 	local function processIncoming(b: buffer, ref: { Instance }?, handleInvokes: boolean)
-		if type(b) ~= "buffer" then
-			return
-		end
-		local contents = Buffer.readEvents(b, ref, eventSchemas)
+		if type(b) ~= "buffer" then return end
+		local decoded: buffer = handleInvokes and Xor.decodeClient(b) or b
+		local contents = Buffer.readEvents(decoded, ref, eventSchemas)
 		for _, content in contents do
 			local remote = content[1]
-			local content = content[2]
+			local args = content[2]
 			if handleInvokes then
 				if remote == 0 then
 					local id = content[1]
@@ -184,17 +186,12 @@ if RunService:IsClient() then
 					continue
 				end
 				if remote == 1 then
-					local remoteName = content[1]
-					local id = content[2]
-					local args = content[3]
+					local remoteName, id, rargs = args[1], args[2], args[3]
 					local connections = eventListeners[remoteName]
 					if connections and #connections > 0 then
 						Thread(function()
-							local results = { connections[1].c(table.unpack(args)) }
-							table.insert(queueEvent, {
-								1,
-								{ id, results } :: any,
-							})
+							local results = { connections[1].c(table.unpack(rargs)) }
+							table.insert(queueEvent, { 1, { id, results } :: any })
 						end)
 					end
 					continue
@@ -203,7 +200,7 @@ if RunService:IsClient() then
 			local connections = eventListeners[remote]
 			if connections then
 				for _, connection in connections do
-					Thread(connection.c, table.unpack(content))
+					Thread(connection.c, table.unpack(args))
 				end
 			end
 		end
@@ -219,21 +216,20 @@ if RunService:IsClient() then
 
 	RunService.PostSimulation:Connect(function(d: number)
 		deltaT += d
-		if deltaT < cycle then
-			return
-		end
+		if deltaT < cycle then return end
 		deltaT = 0
 		
-		-- reliable
+		--reliable
 		if #queueEvent > 0 then
 			Buffer.writeEvents(writer, queueEvent, eventSchemas)
 			do
 				local buf, ref = Buffer.buildWithRefs(writer)
+				local encoded = Xor.encodeClient(buf)
 				Buffer.reset(writer)
 				if not ref or #ref == 0 then
-					Event:FireServer(buf)
+					Event:FireServer(encoded)
 				else
-					Event:FireServer(buf, ref)
+					Event:FireServer(encoded, ref)
 				end
 			end
 			table.clear(queueEvent)

src/Server/init.luau

@@ -3,12 +3,14 @@
 --@EternityDev
 local Server = {}
 
-local Players = game:GetService("Players")
-local RunService = game:GetService("RunService")
 local Thread = require("./Util/Thread")
 local Buffer = require("./Util/Buffer")
 local Identifier = require("./Util/Identifier")
 local Replication = require("./Replication")
+local Xor = require("./Util/Xor")
+
+local Players = game:GetService("Players")
+local RunService = game:GetService("RunService")
 local Event: RemoteEvent = script.Parent:WaitForChild("Event")
 local _repl: RemoteEvent = script.Parent:WaitForChild("_repl")
 local UnreliableEvent: UnreliableRemoteEvent = script.Parent:WaitForChild("UnreliableEvent")
@@ -198,14 +200,15 @@ if RunService:IsServer() then
 			player_bytes[player] = bytes
 		end
 
-		local contents = Buffer.readEvents(b, ref, eventSchemas)
+		local decoded = handleInvokes and Xor.decodeServer(player, b) or b
+		local contents = Buffer.readEvents(decoded, ref, eventSchemas)
 		for _, content in contents do
 			local remote = content[1]
-			local content = content[2]
+			local d = content[2]
 			if handleInvokes then
 				if remote == 1 then
-					local id = content[1]
-					local results = content[2]
+					local id = d[1]
+					local results = d[2]
 					local pending = pendingInvokes[id]
 					if pending then
 						task.spawn(pending :: any, table.unpack(results))
@@ -217,9 +220,9 @@ if RunService:IsServer() then
 					if #eventListeners == 0 then
 						continue
 					end
-					local remoteName = content[1]
-					local id = content[2]
-					local args = content[3]
+					local remoteName = d[1]
+					local id = d[2]
+					local args = d[3]
 					local connections = eventListeners[remoteName]
 					if connections and #connections > 0 then
 						Thread(function()
@@ -239,7 +242,7 @@ if RunService:IsServer() then
 			local connections = eventListeners[remote]
 			if connections then
 				for _, connection in connections do
-					Thread(connection.c, player, table.unpack(content))
+					Thread(connection.c, player, table.unpack(d))
 				end
 			end
 		end
@@ -268,11 +271,12 @@ if RunService:IsServer() then
 			Buffer.writeEvents(writer, content, eventSchemas)
 			do
 				local buf, ref = Buffer.buildWithRefs(writer)
+				local encoded = Xor.encodeServer(player, buf)
 				Buffer.reset(writer)
 				if not ref or #ref == 0 then
-					Event:FireClient(player, buf)
+					Event:FireClient(player, encoded)
 				else
-					Event:FireClient(player, buf, ref)
+					Event:FireClient(player, encoded, ref)
 				end
 			end
 			player_bytes[player] = 0
@@ -324,6 +328,7 @@ if RunService:IsServer() then
 			table.clear(queueUnreliableEvent[player])
 			queueUnreliableEvent[player] = nil
 		end
+		Xor.remove(player)
 	end)
 	for _, player: Player in ipairs(Players:GetPlayers()) do
 		onAdded(player)

src/Util/Xor.luau

@@ -0,0 +1,107 @@
+--!strict
+--!native
+--!optimize 2
+local Xor = {}
+
+type XorEntry = { buf: buffer, len: number }
+
+local serverPrev: { [Player]: XorEntry } = {}
+local clientPrev: { [Player]: XorEntry } = {}
+
+local clientOutPrev: XorEntry? = nil
+local clientInPrev: XorEntry? = nil
+
+local function xorApply(current: buffer, curLen: number, prev: buffer, prevLen: number): buffer
+	local out = buffer.create(curLen)
+	local common = if curLen < prevLen then curLen else prevLen
+
+	local wordEnd = (common // 4) * 4
+	for off = 0, wordEnd - 4, 4 do
+		buffer.writeu32(out, off, bit32.bxor(buffer.readu32(current, off), buffer.readu32(prev, off)))
+	end
+	for i = wordEnd, common - 1 do
+		buffer.writeu8(out, i, bit32.bxor(buffer.readu8(current, i), buffer.readu8(prev, i)))
+	end
+
+	if curLen > common then
+		buffer.copy(out, common, current, common, curLen - common)
+	end
+	return out
+end
+
+local function storeEntry(entry: XorEntry?, src: buffer, len: number): XorEntry
+	local e: XorEntry = entry or { buf = buffer.create(len > 64 and len or 64), len = 0 }
+
+	if buffer.len(e.buf) < len then
+		e.buf = buffer.create(len * 2)
+	end
+
+	buffer.copy(e.buf, 0, src, 0, len)
+	e.len = len
+	return e
+end
+
+function Xor.remove(player: Player)
+	serverPrev[player] = nil
+	clientPrev[player] = nil
+end
+
+function Xor.encodeServer(player: Player, buf: buffer): buffer
+	local len = buffer.len(buf)
+	local entry = serverPrev[player]
+
+	if not entry then
+		serverPrev[player] = storeEntry(nil, buf, len)
+		return buf
+	end
+
+	local encoded = xorApply(buf, len, entry.buf, entry.len)
+	serverPrev[player] = storeEntry(entry, buf, len)
+	return encoded
+end
+
+function Xor.decodeClient(buf: buffer): buffer
+	local len = buffer.len(buf)
+	local prev = clientInPrev
+
+	if not prev then
+		clientInPrev = storeEntry(nil, buf, len)
+		return buf
+	end
+
+	local recovered = xorApply(buf, len, prev.buf, prev.len)
+	clientInPrev = storeEntry(prev, recovered, len)
+	return recovered
+end
+
+function Xor.encodeClient(buf: buffer): buffer
+	local len = buffer.len(buf)
+	local prev = clientOutPrev
+
+	if not prev then
+		clientOutPrev = storeEntry(nil, buf, len)
+		return buf
+	end
+
+	local encoded = xorApply(buf, len, prev.buf, prev.len)
+	clientOutPrev = storeEntry(prev, buf, len)
+	return encoded
+end
+
+function Xor.decodeServer(player: Player, buf: buffer): buffer
+	local len = buffer.len(buf)
+	local entry = clientPrev[player]
+
+	if not entry then
+		clientPrev[player] = storeEntry(nil, buf, len)
+		return buf
+	end
+
+	local recovered = xorApply(buf, len, entry.buf, entry.len)
+	clientPrev[player] = storeEntry(entry, recovered, len)
+	return recovered
+end
+
+Xor._apply = xorApply
+
+return Xor