Method append

pkg/encoding/lorawan/mac.go:1543–1568

(phy band.Band, b []byte, isUplink bool, cmd *ttnpb.MACCommand)

)

func (spec MACCommandSpec) append(phy band.Band, b []byte, isUplink bool, cmd *ttnpb.MACCommand) ([]byte, error) {
	desc, ok := spec[cmd.Cid]
	if !ok || desc == nil {
		return nil, errUnknownMACCommand.WithAttributes("cid", fmt.Sprintf("0x%X", int32(cmd.Cid)))
	}
	b = append(b, byte(cmd.Cid))

	var appender func(phy band.Band, b []byte, cmd *ttnpb.MACCommand) ([]byte, error)
	if isUplink {
		appender = desc.AppendUplink
		if appender == nil {
			return nil, errMACCommandUplink.WithAttributes("cid", fmt.Sprintf("0x%X", int32(cmd.Cid)))
		}
	} else {
		appender = desc.AppendDownlink
		if appender == nil {
			return nil, errMACCommandDownlink.WithAttributes("cid", fmt.Sprintf("0x%X", int32(cmd.Cid)))
		}
	}

	b, err := appender(phy, b, cmd)
	if err != nil {
		return nil, errEncodingMACCommand.WithAttributes("cid", fmt.Sprintf("0x%X", int32(cmd.Cid))).WithCause(err)
	}
	return b, nil
}

// AppendUplink encodes uplink MAC command cmd, appends it to b and returns any errors encountered.
func (spec MACCommandSpec) AppendUplink(phy band.Band, b []byte, cmd *ttnpb.MACCommand) ([]byte, error) {