Initial Art-Net protocol library

receiver.go

@@ -0,0 +1,107 @@
+package artnet
+
+import (
+	"net"
+	"time"
+)
+
+type Handler interface {
+	HandleDMX(src *net.UDPAddr, pkt *DMXPacket)
+	HandlePoll(src *net.UDPAddr, pkt *PollPacket)
+	HandlePollReply(src *net.UDPAddr, pkt *PollReplyPacket)
+}
+
+type Receiver struct {
+	conn    *net.UDPConn
+	handler Handler
+	done    chan struct{}
+}
+
+func NewReceiver(addr *net.UDPAddr, handler Handler) (*Receiver, error) {
+	conn, err := net.ListenUDP("udp4", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Receiver{
+		conn:    conn,
+		handler: handler,
+		done:    make(chan struct{}),
+	}, nil
+}
+
+func NewDefaultReceiver(handler Handler) (*Receiver, error) {
+	return NewReceiver(&net.UDPAddr{Port: Port}, handler)
+}
+
+func (r *Receiver) Start() {
+	go r.loop()
+}
+
+func (r *Receiver) Stop() {
+	close(r.done)
+	r.conn.Close()
+}
+
+func (r *Receiver) Conn() *net.UDPConn {
+	return r.conn
+}
+
+func (r *Receiver) LocalAddr() net.Addr {
+	return r.conn.LocalAddr()
+}
+
+func (r *Receiver) SendTo(data []byte, addr *net.UDPAddr) error {
+	_, err := r.conn.WriteToUDP(data, addr)
+	return err
+}
+
+func (r *Receiver) loop() {
+	buf := make([]byte, 1024)
+
+	for {
+		select {
+		case <-r.done:
+			return
+		default:
+		}
+
+		r.conn.SetReadDeadline(time.Now().Add(1 * time.Second))
+		n, src, err := r.conn.ReadFromUDP(buf)
+		if err != nil {
+			if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
+				continue
+			}
+			select {
+			case <-r.done:
+				return
+			default:
+				continue
+			}
+		}
+
+		r.handle(src, buf[:n])
+	}
+}
+
+func (r *Receiver) handle(src *net.UDPAddr, data []byte) {
+	opCode, pkt, err := ParsePacket(data)
+	if err != nil {
+		return
+	}
+
+	switch opCode {
+	case OpDmx:
+		if dmx, ok := pkt.(*DMXPacket); ok {
+			r.handler.HandleDMX(src, dmx)
+		}
+	case OpPoll:
+		if poll, ok := pkt.(*PollPacket); ok {
+			r.handler.HandlePoll(src, poll)
+		}
+	case OpPollReply:
+		if reply, ok := pkt.(*PollReplyPacket); ok {
+			r.handler.HandlePollReply(src, reply)
+		}
+	}
+}