* Create constants for dirModes

* Update README

README.md

@@ -61,7 +61,6 @@ Here they are:
 | `pixelbin2ascii`      | This mode was designed to address colorized pixels. MQTT-wise you can insert a string like "<0-255> #RRGGBB" which will be converted to 4 byte on the CAN-BUS the first byte will be the number of the LED 0-255 and bytes 1, 2, 3 are the color of red, green and blue.                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
 | `16bool2ascii`        | Interprets two bytes can-wise and publishes them as 16 boolean values to mqtt                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
 | `{i}[u]int{b}2ascii`  | `i` is the amount of instances of numbers in the CAN-Frame/the MQTT-message. Valid instance amounts are currently 1,2,4 and 8. Although other combinations are possible. Might be added in the future, if the need arises. `b` is the size of each number in bits. Supported values are 8,16,32 and 64. You can use either one unsigned or signed integers. This are all possible combinations:  `int82ascii`, `2int82ascii`, `4int82ascii`, `8int82ascii`, `int162ascii`, `2int162ascii`, `4int162ascii`, `int322ascii`, `2int322ascii`, `int642ascii`, `uint82ascii`, `2uint82ascii`, `4uint82ascii`, `8uint82ascii`, `uint162ascii`, `2uint162ascii`, `4uint162ascii`, `uint322ascii`, `2uint322ascii`, `uint642ascii` |
-|
 
 
 ## Unidirectional Mode

src/main.go

@@ -20,7 +20,7 @@ var (
 	debugLog                                 bool
 	canInterface, mqttConnection, configFile string
 	version                                  = "dev"
-	dirMode                                  = 0 // directional modes: 0=bidirectional 1=can2mqtt only 2=mqtt2can only [-d]
+	dirMode                                  = BIDIRECTIONAL // directional modes: 0=bidirectional 1=can2mqtt only 2=mqtt2can only [-d]
 	wg                                       sync.WaitGroup
 )
 
@@ -34,7 +34,7 @@ func main() {
 	flag.IntVar(&dirMode, "d", 0, "direction mode\n0: bidirectional (default)\n1: can2mqtt only\n2: mqtt2can only")
 	flag.Parse()
 
-	if dirMode < 0 || dirMode > 2 {
+	if dirMode < BIDIRECTIONAL || dirMode > MQTT2CAN_ONLY {
 		slog.Error("got invalid value for -d. Valid values are 0 (bidirectional), 1 (can2mqtt only) or 2 (mqtt2can only)", "d", dirMode)
 	}
 

src/receive.go

@@ -13,7 +13,7 @@ import (
 func handleCAN(cf can.Frame) {
 	slog.Debug("received CANFrame", "id", cf.ID, "len", cf.Length, "data", cf.Data)
 	// Only do conversions when necessary
-	if dirMode != 2 {
+	if dirMode != MQTT2CAN_ONLY {
 		mqttPayload, err := pairFromID[cf.ID].convertMode.ToMqtt(cf)
 		if err != nil {
 			slog.Warn("conversion to MQTT message unsuccessful", "convertmode", pairFromID[cf.ID].convertMode, "error", err)
@@ -33,7 +33,7 @@ func handleCAN(cf can.Frame) {
 func handleMQTT(_ MQTT.Client, msg MQTT.Message) {
 	slog.Debug("received message", "topic", msg.Topic(), "payload", msg.Payload())
 
-	if dirMode != 1 {
+	if dirMode != CAN2MQTT_ONLY {
 		cf, err := pairFromTopic[msg.Topic()].convertMode.ToCan(msg.Payload())
 		if err != nil {
 			slog.Warn("conversion to CAN-Frame unsuccessful", "convertmode", pairFromTopic[msg.Topic()].convertMode, "error", err)

src/types.go

@@ -23,4 +23,11 @@ type can2mqtt struct {
 	canId       uint32
 	convertMode ConvertMode
 	mqttTopic   string
-}
+}
+
+// Valid values for "dirMode"
+const (
+	BIDIRECTIONAL = iota
+	CAN2MQTT_ONLY
+	MQTT2CAN_ONLY
+)