func readMapHeader()

in internal/encoding/decode.go [1108:1149]

• 37 lines of code
• 9 McCabe index (conditional complexity)

func readMapHeader(r *buffer.Buffer) (count uint32, _ error) {
	type_, err := readType(r)
	if err != nil {
		return 0, err
	}

	length := r.Len()

	switch type_ {
	case TypeCodeMap8:
		buf, ok := r.Next(2)
		if !ok {
			return 0, errors.New("invalid length")
		}
		_ = buf[1]

		size := int(buf[0])
		if size > length-1 {
			return 0, errors.New("invalid length")
		}
		count = uint32(buf[1])
	case TypeCodeMap32:
		buf, ok := r.Next(8)
		if !ok {
			return 0, errors.New("invalid length")
		}
		_ = buf[7]

		size := int(binary.BigEndian.Uint32(buf[:4]))
		if size > length-4 {
			return 0, errors.New("invalid length")
		}
		count = binary.BigEndian.Uint32(buf[4:8])
	default:
		return 0, fmt.Errorf("invalid map type %#02x", type_)
	}

	if int(count) > r.Len() {
		return 0, errors.New("invalid length")
	}
	return count, nil
}