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Improve perfs - #89
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Pull request overview
This PR addresses performance issue #88 by replacing the O(board size) json_encode($this->board)-based position hashing with an incrementally maintained Zobrist-style hash, so repeated makeMove() / undoMove() calls during move generation don’t re-serialize the entire board.
Changes:
- Introduces
ZobristHasherand integrates it intoChessto maintainboardHashin O(1) per move/undo. - Updates
generateMoves()cache key construction to avoid ambiguity/collisions (adds delimiters + explicit"all"when$squareis null). - Updates tests to assert deterministic hashing and that side-to-move affects the hash.
Reviewed changes
Copilot reviewed 4 out of 5 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
src/Chess.php |
Swaps board hashing to incremental Zobrist updates on make/undo; refactors cache key format; adds refreshBoardHash(). |
src/ZobristHasher.php |
New hasher implementing rebuild/apply/restore for a 64-bit (8-byte) hash encoded as hex. |
src/Entry.php |
Stores a previousPosition hash to enable O(1) hash restoration on undo. |
tests/MiscTest.php |
Updates hash expectations to reflect deterministic Zobrist hashing and side-to-move inclusion. |
.gitignore |
Updates ignore patterns (root *.cache, adds /build/). |
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Fix #88