func()

in internal/remote/codec.go [415:512]
82 lines of code
17 McCabe index (conditional complexity)

func (c *rmqCodec) decodeHeader(data []byte) (*RemotingCommand, error) {
	var err error
	command := &RemotingCommand{}
	buf := bytes.NewBuffer(data)
	var code int16
	err = binary.Read(buf, binary.BigEndian, &code)
	if err != nil {
		return nil, err
	}
	command.Code = code

	var (
		languageCode byte
		remarkLen    int32
		extFieldsLen int32
	)
	err = binary.Read(buf, binary.BigEndian, &languageCode)
	if err != nil {
		return nil, err
	}
	command.Language = LanguageCode(languageCode)

	var version int16
	err = binary.Read(buf, binary.BigEndian, &version)
	if err != nil {
		return nil, err
	}
	command.Version = version

	// int opaque
	err = binary.Read(buf, binary.BigEndian, &command.Opaque)
	if err != nil {
		return nil, err
	}

	// int flag
	err = binary.Read(buf, binary.BigEndian, &command.Flag)
	if err != nil {
		return nil, err
	}

	// String remark
	err = binary.Read(buf, binary.BigEndian, &remarkLen)
	if err != nil {
		return nil, err
	}

	if remarkLen > 0 {
		var remarkData = make([]byte, remarkLen)
		if _, err = io.ReadFull(buf, remarkData); err != nil {
			return nil, err
		}
		command.Remark = string(remarkData)
	}

	err = binary.Read(buf, binary.BigEndian, &extFieldsLen)
	if err != nil {
		return nil, err
	}

	if extFieldsLen > 0 {
		extFieldsData := make([]byte, extFieldsLen)
		if _, err := io.ReadFull(buf, extFieldsData); err != nil {
			return nil, err
		}

		command.ExtFields = make(map[string]string)
		buf := bytes.NewBuffer(extFieldsData)
		var (
			kLen int16
			vLen int32
		)
		for buf.Len() > 0 {
			err = binary.Read(buf, binary.BigEndian, &kLen)
			if err != nil {
				return nil, err
			}

			key, err := getExtFieldsData(buf, int32(kLen))
			if err != nil {
				return nil, err
			}

			err = binary.Read(buf, binary.BigEndian, &vLen)
			if err != nil {
				return nil, err
			}

			value, err := getExtFieldsData(buf, vLen)
			if err != nil {
				return nil, err
			}
			command.ExtFields[key] = value
		}
	}

	return command, nil
}