func readComposite()

in internal/encoding/decode.go [718:831]
99 lines of code
19 McCabe index (conditional complexity)

func readComposite(r *buffer.Buffer) (any, error) {
	buf := r.Bytes()

	if len(buf) < 2 {
		return nil, errors.New("invalid length for composite")
	}

	// compsites start with 0x0
	if AMQPType(buf[0]) != 0x0 {
		return nil, fmt.Errorf("invalid composite header %#02x", buf[0])
	}

	var compositeType uint64
	switch AMQPType(buf[1]) {
	case TypeCodeSmallUlong:
		if len(buf) < 3 {
			return nil, errors.New("invalid length for smallulong")
		}
		compositeType = uint64(buf[2])
	case TypeCodeUlong:
		if len(buf) < 10 {
			return nil, errors.New("invalid length for ulong")
		}
		compositeType = binary.BigEndian.Uint64(buf[2:])
	}

	if compositeType > math.MaxUint8 {
		// try as described type
		var dt DescribedType
		err := dt.Unmarshal(r)
		return dt, err
	}

	switch AMQPType(compositeType) {
	// Error
	case TypeCodeError:
		t := new(Error)
		err := t.Unmarshal(r)
		return t, err

	// Lifetime Policies
	case TypeCodeDeleteOnClose:
		t := DeleteOnClose
		err := t.Unmarshal(r)
		return t, err
	case TypeCodeDeleteOnNoMessages:
		t := DeleteOnNoMessages
		err := t.Unmarshal(r)
		return t, err
	case TypeCodeDeleteOnNoLinks:
		t := DeleteOnNoLinks
		err := t.Unmarshal(r)
		return t, err
	case TypeCodeDeleteOnNoLinksOrMessages:
		t := DeleteOnNoLinksOrMessages
		err := t.Unmarshal(r)
		return t, err

	// Delivery States
	case TypeCodeStateAccepted:
		t := new(StateAccepted)
		err := t.Unmarshal(r)
		return t, err
	case TypeCodeStateModified:
		t := new(StateModified)
		err := t.Unmarshal(r)
		return t, err
	case TypeCodeStateReceived:
		t := new(StateReceived)
		err := t.Unmarshal(r)
		return t, err
	case TypeCodeStateRejected:
		t := new(StateRejected)
		err := t.Unmarshal(r)
		return t, err
	case TypeCodeStateReleased:
		t := new(StateReleased)
		err := t.Unmarshal(r)
		return t, err

	case TypeCodeOpen,
		TypeCodeBegin,
		TypeCodeAttach,
		TypeCodeFlow,
		TypeCodeTransfer,
		TypeCodeDisposition,
		TypeCodeDetach,
		TypeCodeEnd,
		TypeCodeClose,
		TypeCodeSource,
		TypeCodeTarget,
		TypeCodeMessageHeader,
		TypeCodeDeliveryAnnotations,
		TypeCodeMessageAnnotations,
		TypeCodeMessageProperties,
		TypeCodeApplicationProperties,
		TypeCodeApplicationData,
		TypeCodeAMQPSequence,
		TypeCodeAMQPValue,
		TypeCodeFooter,
		TypeCodeSASLMechanism,
		TypeCodeSASLInit,
		TypeCodeSASLChallenge,
		TypeCodeSASLResponse,
		TypeCodeSASLOutcome:
		return nil, fmt.Errorf("readComposite unmarshal not implemented for %#02x", compositeType)

	default:
		// try as described type
		var dt DescribedType
		err := dt.Unmarshal(r)
		return dt, err
	}
}