What open source libraries exist for checking texts for uniqueness?

Question

Windows

Good day.
There are some texts. New ones are added periodically. It is required to check what percentage of the match is in the next added text. The texts are small, one or two A4 pages.
Perhaps there are some open source (and not only) libraries with the implementation of the same shingles algorithm?
Thank you.

Answer 1

What's the problem with implementing it ? Yes, and with Google , everyone has had problems lately.