Chess-Polyglot-Reader

A Chess Opening Book reader that supports Polyglot books of the .bin format. The code is fully documented.

⭐ Features

• Well-documented
• Ability to load and read Polyglot books
• Returns the book moves in a standard format so you can integrate it with your projects (see below)
• Can randomly extract a book move using the zobrist hash of a position
• Can convert a book move to the UCI protocol
• Ability to process and return the move weight and learn values as well
• Everything is in the Reader:: namespace, so it won't pollute your namespace

❔ How to use it?

This is a single header library. Just download reader.hpp or copy the source code.

NOTE: It is assumed that you have implemented proper zobrist hashing in your code. If not, it is recommended you do that first, since it is required to access book moves.

🏁 How to use the book moves in your project?

The book moves are returned in a single format. For example, a book move of type Reader::BookMove called book_move can be used as follows:

• book_move.toFile returns the index of the file of the target square
• book_move.toRow returns the index of the row of the target square
• book_move.fromFile returns the index of the file of the source square
• book_move.fromRow returns the index of the row of the source square
• book_move.promotion returns the type of the promoted piece

FILES: a is 0, b is 1, ... h is 7

ROWS: 0, 1, ... 7

PROMOTIONS: 0 is none, 1 is knight, 2 is bishop, 3 is rook, 4 is queen

Or you can just call Reader::ConvertBookMoveToUci(book_move) and automatically convert a move to the UCI format

🔤 Code example

Reader::Book book;
book.Load("book.bin");
chess::Board board = chess::Board();
board.makeMove("e2e4");
board.makeMove("e7e5");
Reader::BookMoves book_moves = book.GetBookMoves((uint64_t)board.zobrist());
std::cout << Reader::ConvertBookMoveToUci(Reader::RandomBookMove(book_moves)) << std::endl;
book.Clear();

OUTPUT: g1f3

💻 How to help?

Please suggest improvements to the library. I have done my best to eradicate all known bugs from the code. However, if you feel you have found a potential bug, please open a pull request.