Method isNeedToAddEmptyBlock

src/IO/ZstdDeflatingAppendableWriteBuffer.cpp:176–199

}

bool ZstdDeflatingAppendableWriteBuffer::isNeedToAddEmptyBlock()
{
    ReadBufferFromFile reader(out.getFileName());
    auto fsize = reader.getFileSize();
    if (fsize > 3)
    {
        std::array<char, 3> result;
        reader.seek(fsize - 3, SEEK_SET);
        reader.readStrict(result.data(), 3);

        /// If we don't have correct block in the end, then we need to add it manually.
        /// NOTE: maybe we can have the same bytes in case of data corruption/unfinished write.
        /// But in this case file still corrupted and we have to remove it.
        return result != ZSTD_CORRECT_TERMINATION_LAST_BLOCK;
    }
    else if (fsize > 0)
    {
        throw Exception(
            ErrorCodes::ZSTD_ENCODER_FAILED,
            "Trying to write to non-empty file '{}' with tiny size {}. It can lead to data corruption",
            out.getFileName(), fsize);
    }
    return false;
}

}