to_hex

std::string to_hex(const void *data, const unsigned int size) {
    std::stringstream stream;
    stream << std::uppercase << std::hex;
    const unsigned char *bytes = static_cast<const unsigned char *>(data);
    for (unsigned int i = 0; i<size; ++i) {
        stream << std::setfill('0') << std::setw(2) << static_cast<const int>(bytes[i]) << " ";
    }
    return stream.str().substr(0, stream.str().size()-1);
}