internal static ExtMoveArrayWrapper generate_castling(
CastlingRight Cr,
bool Checks,
bool Chess960,
Position pos,
ExtMoveArrayWrapper moveList,
ColorT us,
CheckInfo ci)
{
var KingSide = (Cr == CastlingRight.WHITE_OO || Cr == CastlingRight.BLACK_OO);
if (pos.castling_impeded(Cr) || !pos.can_castle(Cr))
{
return moveList;
}
// After castling, the rook and king final positions are the same in Chess960
// as they would be in standard chess.
var kfrom = pos.square(PieceType.KING, us);
var rfrom = pos.castling_rook_square(Cr);
var kto = Square.relative_square(us, KingSide ? Square.SQ_G1 : Square.SQ_C1);
var enemies = pos.pieces_Ct(Color.opposite(us));
Debug.Assert(pos.checkers() == 0);
var K = Chess960 ? kto > kfrom ? Square.DELTA_W : Square.DELTA_E : KingSide ? Square.DELTA_W : Square.DELTA_E;
for (var s = kto; s != kfrom; s += K)
{
if ((pos.attackers_to(s) & enemies) != 0)
{
return moveList;
}
}
// Because we generate only legal castling moves we need to verify that
// when moving the castling rook we do not discover some hidden checker.
// For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1.
if (Chess960
&& ((Utils.attacks_bb_PtSBb(PieceType.ROOK, kto, Bitboard.XorWithSquare(pos.pieces(), rfrom))
& pos.pieces_CtPtPt(Color.opposite(us), PieceType.ROOK, PieceType.QUEEN)))!= 0)
{
return moveList;
}
var m = Move.make(MoveType.CASTLING, kfrom, rfrom);
if (Checks && !pos.gives_check(m, ci))
{
return moveList;
}
moveList.Add(m);
return moveList;
}
internal SquareT castling_rook_square(CastlingRight cr)
{
return castlingRookSquare[(int) cr];
}
internal bool castling_impeded(CastlingRight cr)
{
return (byTypeBB[PieceType.ALL_PIECES] & castlingPath[(int) cr]) != 0;
}
internal bool can_castle(CastlingRight cr)
{
return (st.castlingRights & (int) cr) != 0;
}
