inline bool guid_parser::hex_octet_to_byte()

in krabs/krabs/guid.hpp [169:211]

• 33 lines of code
• 12 McCabe index (conditional complexity)

    inline bool guid_parser::hex_octet_to_byte(const char* str_input, unsigned char& byte_output)
    {
        // Accepts chars '0' through '9' (0x30 to 0x39),
        // 'A' through 'F' (0x41 to 0x46)
        // 'a' through 'f' (0x61 to 0x66)

        // Narrow the value later, for safety checking.
        auto value = 0;
        // most significant digit in the octet
        auto msd = str_input[0];
        // least significant digit in the octet
        auto lsd = str_input[1];

        if (msd >= '0' && msd <= '9')
        {
            value |= ((int)msd & 0x0F) << 4;
        }
        else if ((msd >= 'A' && msd <= 'F') || (msd >= 'a' && msd <= 'f'))
        {
            value |= (((int)msd & 0x0F) + 9) << 4;
        }
        else
        {
            return false;
        }

        if (lsd >= '0' && lsd <= '9')
        {
            value |= ((int)lsd & 0x0F);
        }
        else if ((lsd >= 'A' && lsd <= 'F') || (lsd >= 'a' && lsd <= 'f'))
        {
            value |= (((int)lsd & 0x0F) + 9);
        }
        else
        {
            return false;
        }

        assert(value >= 0 && value <= UCHAR_MAX);
        byte_output = static_cast<unsigned char>(value);
        return true;
    }