sideToMove = (token == 'w' ? WHITE : BLACK);
fen >> token;
- // 3. Castling availability
+ // 3. Castling availability. Compatible with 3 standards: Normal FEN standard,
+ // Shredder-FEN that uses the letters of the columns on which the rooks began
+ // the game instead of KQkq and also X-FEN standard that, in case of Chess960,
+ // if an inner rook is associated with the castling right, the castling tag is
+ // replaced by the file letter of the involved rook, as for the Shredder-FEN.
while ((fen >> token) && !isspace(token))
- set_castling_rights(token);
+ {
+ Square rsq;
+ Color c = islower(token) ? BLACK : WHITE;
+ Piece rook = make_piece(c, ROOK);
+
+ token = char(toupper(token));
+
+ if (token == 'K')
+ for (rsq = relative_square(c, SQ_H1); piece_on(rsq) != rook; rsq--) {}
+
+ else if (token == 'Q')
+ for (rsq = relative_square(c, SQ_A1); piece_on(rsq) != rook; rsq++) {}
+
+ else if (token >= 'A' && token <= 'H')
+ rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1));
+
+ else
+ continue;
+
+ set_castle_right(king_square(c), rsq);
+ }
// 4. En passant square. Ignore if no pawn capture is possible
if ( ((fen >> col) && (col >= 'a' && col <= 'h'))
&& ((fen >> row) && (row == '3' || row == '6')))
{
st->epSquare = make_square(File(col - 'a'), Rank(row - '1'));
- Color them = flip(sideToMove);
- if (!(attacks_from<PAWN>(st->epSquare, them) & pieces(PAWN, sideToMove)))
+ if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove)))
st->epSquare = SQ_NONE;
}
// handle also common incorrect FEN with fullmove = 0.
startPosPly = Max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK);
- // Various initialisations
- chess960 = isChess960;
- st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove));
-
st->key = compute_key();
st->pawnKey = compute_pawn_key();
st->materialKey = compute_material_key();
st->value = compute_value();
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
+ st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove));
+ chess960 = isChess960;
assert(pos_is_ok());
}
-/// Position::set_castle() is an helper function used to set
-/// correct castling related flags.
+/// Position::set_castle_right() is an helper function used to set castling
+/// rights given the corresponding king and rook starting squares.
-void Position::set_castle(int f, Square ksq, Square rsq) {
+void Position::set_castle_right(Square ksq, Square rsq) {
+
+ int f = (rsq < ksq ? WHITE_OOO : WHITE_OO) << color_of(piece_on(ksq));
st->castleRights |= f;
castleRightsMask[ksq] ^= f;
}
-/// Position::set_castling_rights() sets castling parameters castling avaiability.
-/// This function is compatible with 3 standards: Normal FEN standard, Shredder-FEN
-/// that uses the letters of the columns on which the rooks began the game instead
-/// of KQkq and also X-FEN standard that, in case of Chess960, if an inner Rook is
-/// associated with the castling right, the traditional castling tag will be replaced
-/// by the file letter of the involved rook as for the Shredder-FEN.
-
-void Position::set_castling_rights(char token) {
-
- Color c = islower(token) ? BLACK : WHITE;
-
- Square sqA = relative_square(c, SQ_A1);
- Square sqH = relative_square(c, SQ_H1);
- Square rsq, ksq = king_square(c);
-
- token = char(toupper(token));
-
- if (token == 'K')
- for (rsq = sqH; piece_on(rsq) != make_piece(c, ROOK); rsq--) {}
-
- else if (token == 'Q')
- for (rsq = sqA; piece_on(rsq) != make_piece(c, ROOK); rsq++) {}
-
- else if (token >= 'A' && token <= 'H')
- rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1));
-
- else return;
-
- if (file_of(rsq) < file_of(ksq))
- set_castle(WHITE_OOO << c, ksq, rsq);
- else
- set_castle(WHITE_OO << c, ksq, rsq);
-}
-
-
/// Position::to_fen() returns a FEN representation of the position. In case
/// of Chess960 the Shredder-FEN notation is used. Mainly a debugging function.
// Castling rights
if (pos.can_castle(WHITE_OO))
- set_castle(BLACK_OO, king_square(BLACK), flip(pos.castle_rook_square(WHITE_OO)));
+ set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OO)));
if (pos.can_castle(WHITE_OOO))
- set_castle(BLACK_OOO, king_square(BLACK), flip(pos.castle_rook_square(WHITE_OOO)));
+ set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OOO)));
if (pos.can_castle(BLACK_OO))
- set_castle(WHITE_OO, king_square(WHITE), flip(pos.castle_rook_square(BLACK_OO)));
+ set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OO)));
if (pos.can_castle(BLACK_OOO))
- set_castle(WHITE_OOO, king_square(WHITE), flip(pos.castle_rook_square(BLACK_OOO)));
+ set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OOO)));
// En passant square
if (pos.st->epSquare != SQ_NONE)