bitboard library

Native-only bitboard chess core: board representation, move generation, make/unmake, FEN, and perft.

Do not import this from code that compiles to JavaScript. Bitboards are 64-bit and rely on 64-bit integer literals and operations, which are not representable under dart2js (web ints are doubles). Native (Dart VM / AOT) only. The web build must reach the engine through the package search that runs on package:chess, never this library.

Constants

bishop → const int
black → const int
castleBK → const int
castleBQ → const int
castleWK → const int
castleWQ → const int
fileABb → const int
fileHBb → const int
flagCapture → const int
flagDoublePush → const int
flagEpCapture → const int
flagKingCastle → const int
flagPromoCaptureKnight → const int
flagPromoKnight → const int
flagPromoQueen → const int
flagQueenCastle → const int
flagQuiet → const int
fullBoard → const int
All-ones 64-bit mask (== -1 as a signed VM int).
king → const int
knight → const int
pawn → const int
Piece type indices.
pieceValue → const List<int>
Centipawn material values, indexed by piece type (pawn..king).
queen → const int
rook → const int
startposFen → const String
white → const int
Colors.

Properties

kingAttacks → List<int>
final
knightAttacks → List<int>
Pop the least-significant set bit, returning its index. Mutates via return: callers use sq = lsb(bb); bb &= bb - 1;.
final
pawnAttacks → List<List<int>>
final

Functions

bishopAttacks(int sq, int occ) → int
Bishop attacks from sq given full-board occupancy.
encodeMove(int from, int to, int flag) → int
evaluateMaterialPst(Position p) → int
Material + piece-square tables only. Kept as the A/B baseline for the extra terms in evaluatePosition (self-play verification).
evaluatePosition(Position p) → int
Static evaluation from the side-to-move's perspective, in centipawns.
lsb(int bb) → int
Index of the least-significant set bit. bb must be non-zero.
moveFlag(int m) → int
moveFrom(int m) → int
moveIsCapture(int m) → bool
moveIsCastle(int m) → bool
moveIsEnPassant(int m) → bool
moveIsPromotion(int m) → bool
movePromoType(int m) → int
Promotion piece type (knight..queen) for a promotion move.
moveTo(int m) → int
msb(int bb) → int
Index of the most-significant set bit. bb must be non-zero.
perft(Position p, int depth) → int
Count leaf nodes at depth — the standard move-generator correctness test.
popcount(int bb) → int
Number of set bits. Kernighan's method; fine for eval-frequency use.
queenAttacks(int sq, int occ) → int
Queen attacks from sq given full-board occupancy.
rookAttacks(int sq, int occ) → int
Rook attacks from sq given full-board occupancy.