        std::string PngChunk::writeRawProfile(const std::string& profileData, const char* profileType)
        {
            static byte hex[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

            std::ostringstream oss;
            oss << '\n' << profileType << '\n' << std::setw(8) << profileData.size();
            const char* sp = profileData.data();
            for (std::string::size_type i = 0; i < profileData.size(); ++i) {
                if (i % 36 == 0)
                    oss << '\n';
                oss << hex[((*sp >> 4) & 0x0f)];
                oss << hex[((*sp++) & 0x0f)];
            }
            oss << '\n';
            return oss.str();

        }  // PngChunk::writeRawProfile
Unknown