SLIPdecoder

SLIPDecoder.sc

@@ -0,0 +1,67 @@
+SLIPDecoder {
+	var deviceName, <>rate, <>port, decode, <>actions, <>addresses, <numAddresses;
+
+	*new {|deviceName="/dev/cu.SLAB_USBtoUART", rate=9600, numAddresses=3|
+
+		^super.new.initSLIPDecoder(deviceName, rate, numAddresses);
+	}
+
+	initSLIPDecoder {|a,b,c|
+		deviceName = a;
+		rate = b;
+		numAddresses = c;
+		port = SerialPort(deviceName, rate);
+		actions = {}!numAddresses; //second byte in the data array is its address if it's properly configured in OSC. This value is used to select between a number of actions which can be externally set. Each action is a function that takes the message contents as an argument. see 'decode' below. 
+		decode = {|data| //function for decoding the properly-SLIP-decoded message. 
+			var temp = 0!15, address, output;
+			//data[1].asAscii.postln;
+			address = data[1].asAscii.asString.asInt;
+			//":".post;
+			output = (data[data.size-2].asBinaryDigits.at([6,7]) ++ data[data.size-1].asBinaryDigits).convertDigits(2);
+			actions[address].value(output);
+		}
+	}
+
+	start {
+		fork {
+			// SLIP DECODING
+			// ===================
+			//
+			// The packets are SLIP encoded using these special characters:
+			// end = 8r300 (2r11000000 or 0xc0 or 192)
+			// esc = 8r333 (2r11011011 or 0xdb or 219)
+			// esc_end = 8r334 (2r011011100 or 0xdc or 220)
+			// esc_esc = 8r335 (2r011011101 or 0xdd or 221)
+
+			var buffer, serialByte;
+			var maxPacketSize = 64; // 16 is enouch for 8 10 bit values.
+			var slipEND = 8r300;
+			var slipESC = 8r333;
+			var slipESC_END = 8r334;
+			var slipESC_ESC = 8r335;
+			buffer = Int8Array(maxSize:maxPacketSize);
+			{
+				serialByte = port.read;
+				serialByte.switch(
+					slipEND, {
+						decode.value(buffer);
+						buffer = Int8Array(maxSize:maxPacketSize);
+					},
+					slipESC, {
+						serialByte = port.read;
+						serialByte.switch(
+							slipESC_END, { buffer.add(slipEND) },
+							slipESC_ESC, { buffer.add(slipESC) },
+							{"SLIP encoding error.".error }
+						)
+					},
+					{ buffer.add(serialByte) }
+				);
+			}.loop
+		}
+
+
+
+	}
+
+}