View difference between Paste ID: pDNfjk30 and QTwgLZMA

--- Minified CRC32 blob - MIT license - from here: https://raw.githubusercontent.com/davidm/lua-digest-crc32lua/master/lmod/digest/crc32lua.lua
+-- converts a value between 0 and 127 to bits, least significant bits first
-do
+local function to_bits(charbyte)
-	local type=type;local require=require;local setmetatable=setmetatable;local a=bit.bxor;local b=bit.bnot;local c=bit.band;local d=bit.brshift;local e=0xEDB88320;local function f(g)local h={}local i=setmetatable({},h)function h:__index(j)local k=g(j)i[j]=k;return k end;return i end;local l=f(function(m)local n=m;for o=1,8 do local p=c(n,1)n=d(n,1)if p==1 then n=a(n,e)end end;return n end)local function q(r,n)n=b(n or 0)local s=d(n,8)local t=l[a(n%256,r)]return b(a(s,t))end;local function u(v,n)n=n or 0;for m=1,#v do n=q(v:byte(m),n)end;return n end;function crc32(v,n)if type(v)=='string'then return u(v,n)else return q(v,n)end end
+	if charbyte > 127 then error "invalid character" end
 	local out = {}
 	for i = 0, 6 do
-local function get_byte(num, byte)
+		local bitmask = bit.blshift(1, i)
-    return bit.band(bit.brshift(num, byte * 8), 0xFF)
+		local bit = bit.brshift(bit.band(bitmask, charbyte), i)
 		table.insert(out, bit)
 	end
-local function from_bytes(b)
+	return out
-    local n = 0
+
-    for ix, byte in pairs(b) do
+
-        n = bit.bor(n, bit.blshift(byte, (ix - 1) * 8))
+local function from_bits(bit_table)
 	local int = 0
-    return n
+	for i = 0, 6 do
 		local index = i + 1 -- Lua...
 		int = bit.bor(int, bit.blshift(bit_table[index], i))
-local side = settings.get "bundlenet.side" or "back"
+
 	return int
-local function send_raw(str)
+
-	local i = 1
+
-	for i = 1, math.ceil(#str / 2) do
+local rx_side = settings.get "rx_side" or "right"
-		local first = str:byte(i * 2 - 1)
+local tx_side = settings.get "tx_side" or "left"
-		local second = str:byte(i * 2) or 0
+
-		local u16 = first * 256 + second
+local function send(str)
-		rs.setBundledOutput(side, u16)
+	str = "\127" .. str
-		sleep(0.1)
+	for i = 1, #str do
 		local byte = str:byte(i)
-	rs.setBundledOutput(side, 0)
+		for _, bit in ipairs(to_bits(byte)) do
 			rs.setOutput(tx_side, bit == 1)
 			sleep(0.1)
-local function receive_raw(length)
+
 	end
-	local count = 0
+	rs.setOutput(tx_side, false)
-	os.pullEvent "redstone"
+
 
-		local u16 = rs.getBundledInput(side)
+local function receive(char_callback)
-		local first = string.char(math.floor(u16 / 256))
+
-		if not length and first == "\0" then break
+	repeat
-		else
+		os.pullEvent "redstone"
-			count = count + 1
+	until rs.getInput(rx_side)
-			str = str .. first
+
-			if count == length then break end
+		local bits = {}
-			local second = string.char(u16 % 256)
+		for i = 0, 6 do
-			if not length and second == "\0" then break
+			if rs.getInput(rx_side) then
 				table.insert(bits, 1)
-				count = count + 1
+
-				str = str .. second
+				table.insert(bits, 0)
-				if count == length then break end
+
 			sleep(0.1)
 		end
-		sleep(0.1)
+		local char = string.char(from_bits(bits))
 		if char == "\0" then break end
-	return str
+		if char ~= "\127" and char_callback then char_callback(char) end
 		str = str .. char
 	end
-local function u32_to_string(u32)
+	return str:sub(2)
-	return string.char(get_byte(u32, 0), get_byte(u32, 1), get_byte(u32, 2), get_byte(u32, 3))
+
 
 local w, h = term.getSize()
-local function string_to_u32(str)
+local send_window = window.create(term.current(), 1, h, w, 1)
-	return from_bytes{str:byte(1), str:byte(2), str:byte(3), str:byte(4)}
+local message_window = window.create(term.current(), 1, 1, w, h - 1)
 
 local function exec_in_window(w, f)
-local function send(data)
+    local x, y = term.getCursorPos()
-	local length = u32_to_string(#data)
+    local last = term.redirect(w)
-	local checksum = u32_to_string(crc32(data))
+    f()
-	print("len", length, "checksum", checksum)
+    term.redirect(last)
-	send_raw(length)
+    w.redraw()
-	send_raw(checksum)
+    term.setCursorPos(x, y)
-	send_raw(data)
+
 
 local function write_char(txt)
-local function receive()
+    exec_in_window(message_window, function()
-	local length = receive_raw(4)
+        write(txt)
-	sleep(0.1)
+    end)
-	local checksum = receive_raw(4)
+
-	print("len", length, "checksum", checksum, "l", string_to_u32(length), "c", string_to_u32(checksum))
+
-	sleep(0.1)
+local function sender()
-	local data = receive_raw(string_to_u32(length))
+    term.redirect(send_window)
-	if crc32(data) ~= string_to_u32(checksum) then return false, "checksum mismatch", data end
+    term.setBackgroundColor(colors.lightGray)
-	return true, data
+    term.setTextColor(colors.white)
     term.clear()
     while true do
-local option = ...
+        local msg = read()
 		send(msg)
-if option == "send" then
+
-	write "Send: "
+
-	local text = read()
+
-	send(text)
+local function receiver()
-elseif option == "raw_receive" then
+
-	print(receive_raw())
+		receive(write_char)
-elseif option == "receive" then
+		write_char "\n"
-	print(receive())
+
 end
 
-return { send = send, receive = receive }
+parallel.waitForAll(sender, receiver)