/// string. This function is not very robust - make sure that input FENs are
/// correct (this is assumed to be the responsibility of the GUI).
-void Position::from_fen(const string& fen, bool isChess960) {
+void Position::from_fen(const string& fenStr, bool isChess960) {
/*
A FEN string defines a particular position using only the ASCII character set.
char col, row, token;
size_t p;
Square sq = SQ_A8;
- std::istringstream ss(fen);
+ std::istringstream fen(fenStr);
clear();
- ss >> std::noskipws;
+ fen >> std::noskipws;
// 1. Piece placement
- while ((ss >> token) && !isspace(token))
+ while ((fen >> token) && !isspace(token))
{
if (token == '/')
sq -= Square(16); // Jump back of 2 rows
}
// 2. Active color
- ss >> token;
+ fen >> token;
sideToMove = (token == 'w' ? WHITE : BLACK);
- ss >> token;
+ fen >> token;
// 3. Castling availability
- while ((ss >> token) && !isspace(token))
+ while ((fen >> token) && !isspace(token))
set_castling_rights(token);
// 4. En passant square. Ignore if no pawn capture is possible
- if ( ((ss >> col) && (col >= 'a' && col <= 'h'))
- && ((ss >> row) && (row == '3' || row == '6')))
+ 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 = opposite_color(sideToMove);
}
// 5-6. Halfmove clock and fullmove number
- ss >> std::skipws >> st->rule50 >> fullMoves;
+ fen >> std::skipws >> st->rule50 >> fullMoves;
// Various initialisations
chess960 = isChess960;
const string Position::to_fen() const {
- string fen;
+ std::ostringstream fen;
Square sq;
- char emptyCnt;
+ int emptyCnt;
- for (Rank rank = RANK_8; rank >= RANK_1; rank--, fen += '/')
+ for (Rank rank = RANK_8; rank >= RANK_1; rank--)
{
- emptyCnt = '0';
+ emptyCnt = 0;
for (File file = FILE_A; file <= FILE_H; file++)
{
if (!square_is_empty(sq))
{
- if (emptyCnt != '0')
+ if (emptyCnt)
{
- fen += emptyCnt;
- emptyCnt = '0';
+ fen << emptyCnt;
+ emptyCnt = 0;
}
- fen += PieceToChar[piece_on(sq)];
- } else
+ fen << PieceToChar[piece_on(sq)];
+ }
+ else
emptyCnt++;
}
- if (emptyCnt != '0')
- fen += emptyCnt;
+ if (emptyCnt)
+ fen << emptyCnt;
+
+ if (rank > RANK_1)
+ fen << '/';
}
- fen += (sideToMove == WHITE ? " w " : " b ");
+ fen << (sideToMove == WHITE ? " w " : " b ");
if (st->castleRights != CASTLES_NONE)
{
if (can_castle(WHITE_OO))
- fen += chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OO))))) : 'K';
+ fen << (chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OO))))) : 'K');
if (can_castle(WHITE_OOO))
- fen += chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OOO))))) : 'Q';
+ fen << (chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OOO))))) : 'Q');
if (can_castle(BLACK_OO))
- fen += chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OO))) : 'k';
+ fen << (chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OO))) : 'k');
if (can_castle(BLACK_OOO))
- fen += chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OOO))) : 'q';
+ fen << (chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OOO))) : 'q');
} else
- fen += '-';
+ fen << '-';
- fen += (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square()));
- return fen;
+ fen << (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square()))
+ << " " << st->rule50 << " " << fullMoves;
+
+ return fen.str();
}
if (move)
{
Position p(*this, thread());
- string dd = (piece_color(piece_on(move_from(move))) == BLACK ? ".." : "");
+ string dd = (sideToMove == BLACK ? ".." : "");
cout << "\nMove is: " << dd << move_to_san(p, move);
}
/// Position:hidden_checkers<>() returns a bitboard of all pinned (against the
-/// king) pieces for the given color and for the given pinner type. Or, when
-/// template parameter FindPinned is false, the pieces of the given color
-/// candidate for a discovery check against the enemy king.
-/// Bitboard checkersBB must be already updated when looking for pinners.
+/// king) pieces for the given color. Or, when template parameter FindPinned is
+/// false, the function return the pieces of the given color candidate for a
+/// discovery check against the enemy king.
template<bool FindPinned>
Bitboard Position::hidden_checkers(Color c) const {
- Bitboard result = EmptyBoardBB;
+ // Pinned pieces protect our king, dicovery checks attack the enemy king
+ Bitboard b, result = EmptyBoardBB;
Bitboard pinners = pieces(FindPinned ? opposite_color(c) : c);
-
- // Pinned pieces protect our king, dicovery checks attack
- // the enemy king.
Square ksq = king_square(FindPinned ? c : opposite_color(c));
- // Pinners are sliders, not checkers, that give check when candidate pinned is removed
- pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq]) | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]);
-
- if (FindPinned && pinners)
- pinners &= ~st->checkersBB;
+ // Pinners are sliders, that give check when candidate pinned is removed
+ pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq])
+ | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]);
while (pinners)
{
- Square s = pop_1st_bit(&pinners);
- Bitboard b = squares_between(s, ksq) & occupied_squares();
-
- assert(b);
+ b = squares_between(ksq, pop_1st_bit(&pinners)) & occupied_squares();
- if ( !(b & (b - 1)) // Only one bit set?
- && (b & pieces(c))) // Is an our piece?
+ // Only one bit set and is an our piece?
+ if (b && !(b & (b - 1)) && (b & pieces(c)))
result |= b;
}
return result;
assert(piece_color(piece_on(from)) == us);
assert(piece_on(king_square(us)) == make_piece(us, KING));
- // En passant captures are a tricky special case. Because they are
- // rather uncommon, we do it simply by testing whether the king is attacked
- // after the move is made
+ // En passant captures are a tricky special case. Because they are rather
+ // uncommon, we do it simply by testing whether the king is attacked after
+ // the move is made.
if (move_is_ep(m))
{
Color them = opposite_color(us);
Square to = move_to(m);
- Square capsq = make_square(square_file(to), square_rank(from));
+ Square capsq = to + pawn_push(them);
Square ksq = king_square(us);
Bitboard b = occupied_squares();
}
-/// Position::move_is_pl_slow() takes a move and tests whether the move
-/// is pseudo legal. This version is not very fast and should be used
-/// only in non time-critical paths.
-
-bool Position::move_is_pl_slow(const Move m) const {
-
- MoveStack mlist[MAX_MOVES];
- MoveStack *cur, *last;
+/// Position::move_is_legal() takes a move and tests whether the move
+/// is legal. This version is not very fast and should be used only
+/// in non time-critical paths.
- last = in_check() ? generate<MV_EVASION>(*this, mlist)
- : generate<MV_NON_EVASION>(*this, mlist);
+bool Position::move_is_legal(const Move m) const {
- for (cur = mlist; cur != last; cur++)
- if (cur->move == m)
+ for (MoveList<MV_LEGAL> ml(*this); !ml.end(); ++ml)
+ if (ml.move() == m)
return true;
return false;
// Use a slower but simpler function for uncommon cases
if (move_is_special(m))
- return move_is_pl_slow(m);
+ return move_is_legal(m);
// Is not a promotion, so promotion piece must be empty
if (promotion_piece_type(m) - 2 != PIECE_TYPE_NONE)
// Set en passant square, only if moved pawn can be captured
if ((to ^ from) == 16)
{
- if (attacks_from<PAWN>(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them))
+ if (attacks_from<PAWN>(from + pawn_push(us), us) & pieces(PAWN, them))
{
st->epSquare = Square((int(from) + int(to)) / 2);
key ^= zobEp[st->epSquare];
{
if (ep) // en passant ?
{
- capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S);
+ capsq = to + pawn_push(them);
assert(to == st->epSquare);
assert(relative_rank(opposite_color(them), to) == RANK_6);
Square capsq = to;
if (ep)
- capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
+ capsq = to - pawn_push(us);
assert(st->capturedType != KING);
assert(!ep || square_is_empty(capsq));
// Handle en passant moves
if (st->epSquare == to && piece_type(piece_on(from)) == PAWN)
{
- Square capQq = (side_to_move() == WHITE ? to - DELTA_N : to - DELTA_S);
+ Square capQq = to - pawn_push(side_to_move());
assert(capturedType == PIECE_TYPE_NONE);
assert(piece_type(piece_on(capQq)) == PAWN);