combine multi byte fields into one field

diagdata.go

@@ -0,0 +1,88 @@
+package artnet
+
+import (
+	"encoding/binary"
+	"errors"
+	"slices"
+)
+
+type DiagPriority uint8
+
+const (
+	DpLow      DiagPriority = 0x10
+	DpMed      DiagPriority = 0x40
+	DpHigh     DiagPriority = 0x80
+	DpCritical DiagPriority = 0xe0
+	DpVolatile DiagPriority = 0xf0
+)
+
+type ArtDiagData struct {
+	ID           [8]uint8
+	OpCode       uint16
+	ProtVerHi    uint8
+	ProtVerLo    uint8
+	filler1      uint8
+	DiagPriority DiagPriority
+	LogicalPort  uint8
+	filler3      uint8
+	Length       uint16
+	Data         []uint8
+}
+
+func (ap *ArtDiagData) GetOpCode() uint16 {
+	return ap.OpCode
+}
+
+func (ap *ArtDiagData) GetProtVer() uint16 {
+	return uint16(ap.ProtVerHi)<<8 + uint16(ap.ProtVerLo)
+}
+
+func (ap *ArtDiagData) GetID() [8]uint8 {
+	return ap.ID
+}
+
+func (ap *ArtDiagData) UnmarshalBinary(data []byte) error {
+
+	if len(data) < 18 {
+		return errors.New("ArtDiagData packet must be at least 18 bytes long")
+	}
+
+	copy(ap.ID[:], data[0:8])
+
+	if !slices.Equal(ArtNetID[:], ap.ID[:]) {
+		return errors.New("ID does not match Art-Net ID")
+	}
+
+	ap.OpCode = binary.LittleEndian.Uint16(data[8:10])
+	ap.ProtVerHi = data[10]
+	ap.ProtVerLo = data[11]
+
+	offset := 12
+	ap.filler1 = data[offset]
+	ap.DiagPriority = DiagPriority(data[offset+1])
+	ap.LogicalPort = data[offset+2]
+	ap.filler3 = data[offset+3]
+	ap.Length = binary.LittleEndian.Uint16(data[offset+4 : offset+6])
+
+	if len(data[offset+6:]) < int(ap.Length) {
+		return errors.New("[]byte length not long enough to contain data length specified in packet")
+	}
+	ap.Data = make([]uint8, ap.Length)
+	copy(ap.Data, data[offset+6:offset+6+int(ap.Length)])
+	return nil
+}
+
+func (ap *ArtDiagData) MarshalBinary() ([]byte, error) {
+	data := make([]byte, 8+10)
+	copy(data[0:8], ap.ID[:])
+	binary.LittleEndian.PutUint16(data[8:10], ap.OpCode)
+	data[10] = ap.ProtVerHi
+	data[11] = ap.ProtVerLo
+	data[12] = ap.filler1
+	data[13] = uint8(ap.DiagPriority)
+	data[14] = ap.LogicalPort
+	data[15] = ap.filler3
+	binary.LittleEndian.PutUint16(data[16:18], ap.Length)
+	data = append(data, ap.Data...)
+	return data, nil
+}