Function Base64DecodeUneven

library/cpp/string_utils/base64/base64.cpp:271–284

}

size_t Base64DecodeUneven(void* dst, const TStringBuf s) {
    const size_t tailSize = s.length() % 4;
    if (tailSize == 0) {
        return Base64Decode(dst, s.begin(), s.end());
    }

    // divide s into even part and tail and decode in two step, to avoid memory allocation
    char tail[4] = {'=', '=', '=', '='};
    memcpy(tail, s.end() - tailSize, tailSize);
    size_t decodedEven = s.length() > 4 ? Base64Decode(dst, s.begin(), s.end() - tailSize) : 0;
    // there should not be tail of size 1 it's incorrect for 8-bit bytes
    size_t decodedTail = tailSize != 1 ? Base64Decode(static_cast<char*>(dst) + decodedEven, tail, tail + 4) : 0;
    return decodedEven + decodedTail;
}

TString Base64DecodeUneven(const TStringBuf s) {
    TString ret;