Function encodeBase64

src/string.cpp:36–44

Based on https://stackoverflow.com/a/63711162/40645

// Based on https://stackoverflow.com/a/63711162/40645
string encodeBase64(const unsigned char *input, int n) {
    const auto predicted_len = 4 * ((n + 2) / 3);  // predict output size
    const auto output_buffer{make_unique<char[]>(predicted_len + 1)};
    const auto output_len = EVP_EncodeBlock(reinterpret_cast<unsigned char *>(output_buffer.get()), input, n);
    if (predicted_len != static_cast<uint64_t>(output_len)) {
        throw runtime_error("base64 encoding error");
    }
    return output_buffer.get();
}

// Make strings, such as error strings, a little easier on the eyes.
string PrettifySentence(string s) {