Function hexchar_to_base10

src/Chain/libraries/glua/glua_tokenparser.cpp:221–224

        }

        static inline int hexchar_to_base10(int c)
        {
            return is_digit(c) ? (c - '0') : (is_big_alpha(c) ? (c - 'A' + 10) : (c - 'a' + 10));
        }

        void GluaTokenParser::_loadhexaesc(std::string &code, std::stringstream *ss)
        {