add basic start on artnet decoding

packet.go

@@ -0,0 +1,37 @@
+package artnet
+
+import (
+	"encoding/binary"
+	"errors"
+	"slices"
+)
+
+type ArtNetPacket interface {
+	GetOpCode() uint16
+}
+
+var ArtNetID []uint8 = []uint8{'A', 'r', 't', '-', 'N', 'e', 't', 0x00}
+
+type ArtNetHeader struct {
+	ID        []uint8
+	OpCode    uint16
+	ProtVerHi uint8
+	ProtVerLo uint8
+}
+
+func NewHeader(data []byte) (*ArtNetHeader, error) {
+	if len(data) < 12 {
+		return nil, errors.New("header must be at least 12 bytes")
+	}
+
+	if !slices.Equal(ArtNetID, data[0:8]) {
+		return nil, errors.New("header id does not match Art-Net ID")
+	}
+
+	return &ArtNetHeader{
+		OpCode:    binary.LittleEndian.Uint16(data[8:10]),
+		ProtVerHi: data[10],
+		ProtVerLo: data[11],
+	}, nil
+
+}