/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#if !defined(POSITION_H_INCLUDED)
+#ifndef POSITION_H_INCLUDED
#define POSITION_H_INCLUDED
#include <cassert>
-#include <cstddef>
+#include <cstddef> // For offsetof()
+#include <deque>
+#include <memory> // For std::unique_ptr
+#include <string>
+#include <vector>
#include "bitboard.h"
#include "types.h"
-
-/// The checkInfo struct is initialized at c'tor time and keeps info used
-/// to detect if a move gives check.
class Position;
-struct Thread;
+class Thread;
+
+namespace PSQT {
+
+ extern Score psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB];
+
+ void init();
+}
+
+/// CheckInfo struct is initialized at constructor time and keeps info used to
+/// detect if a move gives check.
struct CheckInfo {
Bitboard dcCandidates;
Bitboard pinned;
- Bitboard checkSq[PIECE_TYPE_NB];
- Square ksq;
+ Bitboard checkSquares[PIECE_TYPE_NB];
+ Square ksq;
};
-/// The StateInfo struct stores information we need to restore a Position
-/// object to its previous state when we retract a move. Whenever a move
-/// is made on the board (by calling Position::do_move), a StateInfo object
-/// must be passed as a parameter.
+/// StateInfo struct stores information needed to restore a Position object to
+/// its previous state when we retract a move. Whenever a move is made on the
+/// board (by calling Position::do_move), a StateInfo object must be passed.
struct StateInfo {
- Key pawnKey, materialKey;
- Value npMaterial[COLOR_NB];
- int castleRights, rule50, pliesFromNull;
- Score psqScore;
+
+ // Copied when making a move
+ Key pawnKey;
+ Key materialKey;
+ Value nonPawnMaterial[COLOR_NB];
+ int castlingRights;
+ int rule50;
+ int pliesFromNull;
+ Score psq;
Square epSquare;
- Key key;
- Bitboard checkersBB;
- PieceType capturedType;
+ // Not copied when making a move
+ Key key;
+ Bitboard checkersBB;
+ PieceType capturedType;
StateInfo* previous;
};
+// In a std::deque references to elements are unaffected upon resizing
+typedef std::unique_ptr<std::deque<StateInfo>> StateListPtr;
-/// When making a move the current StateInfo up to 'key' excluded is copied to
-/// the new one. Here we calculate the quad words (64bits) needed to be copied.
-const size_t StateCopySize64 = offsetof(StateInfo, key) / sizeof(uint64_t) + 1;
-
-
-/// The position data structure. A position consists of the following data:
-///
-/// * For each piece type, a bitboard representing the squares occupied
-/// by pieces of that type.
-/// * For each color, a bitboard representing the squares occupied by
-/// pieces of that color.
-/// * A bitboard of all occupied squares.
-/// * A bitboard of all checking pieces.
-/// * A 64-entry array of pieces, indexed by the squares of the board.
-/// * The current side to move.
-/// * Information about the castling rights for both sides.
-/// * The initial files of the kings and both pairs of rooks. This is
-/// used to implement the Chess960 castling rules.
-/// * The en passant square (which is SQ_NONE if no en passant capture is
-/// possible).
-/// * The squares of the kings for both sides.
-/// * Hash keys for the position itself, the current pawn structure, and
-/// the current material situation.
-/// * Hash keys for all previous positions in the game for detecting
-/// repetition draws.
-/// * A counter for detecting 50 move rule draws.
+
+/// Position class stores information regarding the board representation as
+/// pieces, side to move, hash keys, castling info, etc. Important methods are
+/// do_move() and undo_move(), used by the search to update node info when
+/// traversing the search tree.
class Position {
+
public:
- Position() {}
- Position(const Position& p, Thread* t) { *this = p; thisThread = t; }
- Position(const std::string& f, bool c960, Thread* t) { set(f, c960, t); }
- Position& operator=(const Position&);
+ static void init();
- // Text input/output
- void set(const std::string& fen, bool isChess960, Thread* th);
+ Position() = default;
+ Position(const Position&) = delete;
+ Position& operator=(const Position&) = delete;
+
+ // FEN string input/output
+ Position& set(const std::string& fenStr, bool isChess960, StateInfo* si, Thread* th);
const std::string fen() const;
- const std::string pretty(Move m = MOVE_NONE) const;
// Position representation
Bitboard pieces() const;
Bitboard pieces(Color c, PieceType pt) const;
Bitboard pieces(Color c, PieceType pt1, PieceType pt2) const;
Piece piece_on(Square s) const;
- Square king_square(Color c) const;
Square ep_square() const;
- bool is_empty(Square s) const;
- const Square* piece_list(Color c, PieceType pt) const;
- int piece_count(Color c, PieceType pt) const;
+ bool empty(Square s) const;
+ template<PieceType Pt> int count(Color c) const;
+ template<PieceType Pt> const Square* squares(Color c) const;
+ template<PieceType Pt> Square square(Color c) const;
// Castling
- int can_castle(CastleRight f) const;
int can_castle(Color c) const;
- bool castle_impeded(Color c, CastlingSide s) const;
- Square castle_rook_square(Color c, CastlingSide s) const;
+ int can_castle(CastlingRight cr) const;
+ bool castling_impeded(CastlingRight cr) const;
+ Square castling_rook_square(CastlingRight cr) const;
// Checking
Bitboard checkers() const;
Bitboard discovered_check_candidates() const;
- Bitboard pinned_pieces() const;
+ Bitboard pinned_pieces(Color c) const;
// Attacks to/from a given square
Bitboard attackers_to(Square s) const;
- Bitboard attackers_to(Square s, Bitboard occ) const;
- Bitboard attacks_from(Piece p, Square s) const;
- static Bitboard attacks_from(Piece p, Square s, Bitboard occ);
+ Bitboard attackers_to(Square s, Bitboard occupied) const;
+ Bitboard attacks_from(Piece pc, Square s) const;
template<PieceType> Bitboard attacks_from(Square s) const;
template<PieceType> Bitboard attacks_from(Square s, Color c) const;
+ Bitboard slider_blockers(Bitboard target, Bitboard sliders, Square s) const;
// Properties of moves
- bool move_gives_check(Move m, const CheckInfo& ci) const;
- bool pl_move_is_legal(Move m, Bitboard pinned) const;
- bool is_pseudo_legal(const Move m) const;
- bool is_capture(Move m) const;
- bool is_capture_or_promotion(Move m) const;
- bool is_passed_pawn_push(Move m) const;
- Piece piece_moved(Move m) const;
+ bool legal(Move m, Bitboard pinned) const;
+ bool pseudo_legal(const Move m) const;
+ bool capture(Move m) const;
+ bool capture_or_promotion(Move m) const;
+ bool gives_check(Move m, const CheckInfo& ci) const;
+ bool advanced_pawn_push(Move m) const;
+ Piece moved_piece(Move m) const;
PieceType captured_piece_type() const;
// Piece specific
- bool pawn_is_passed(Color c, Square s) const;
- bool pawn_on_7th(Color c) const;
+ bool pawn_passed(Color c, Square s) const;
bool opposite_bishops() const;
- bool bishop_pair(Color c) const;
// Doing and undoing moves
- void do_move(Move m, StateInfo& st);
- void do_move(Move m, StateInfo& st, const CheckInfo& ci, bool moveIsCheck);
+ void do_move(Move m, StateInfo& st, bool givesCheck);
void undo_move(Move m);
void do_null_move(StateInfo& st);
void undo_null_move();
// Static exchange evaluation
- int see(Move m, int asymmThreshold = 0) const;
- int see_sign(Move m) const;
+ Value see(Move m) const;
+ Value see_sign(Move m) const;
// Accessing hash keys
Key key() const;
+ Key key_after(Move m) const;
Key exclusion_key() const;
- Key pawn_key() const;
Key material_key() const;
-
- // Incremental piece-square evaluation
- Score psq_score() const;
- Score psq_delta(Piece p, Square from, Square to) const;
- Value non_pawn_material(Color c) const;
+ Key pawn_key() const;
// Other properties of the position
Color side_to_move() const;
+ Phase game_phase() const;
int game_ply() const;
bool is_chess960() const;
Thread* this_thread() const;
- int64_t nodes_searched() const;
- void set_nodes_searched(int64_t n);
- template<bool SkipRepetition> bool is_draw() const;
+ uint64_t nodes_searched() const;
+ void set_nodes_searched(uint64_t n);
+ bool is_draw() const;
+ int rule50_count() const;
+ Score psq_score() const;
+ Value non_pawn_material(Color c) const;
// Position consistency check, for debugging
- bool pos_is_ok(int* failedStep = NULL) const;
+ bool pos_is_ok(int* failedStep = nullptr) const;
void flip();
private:
// Initialization helpers (used while setting up a position)
- void clear();
- void put_piece(Piece p, Square s);
- void set_castle_right(Color c, Square rfrom);
+ void set_castling_right(Color c, Square rfrom);
+ void set_state(StateInfo* si) const;
- // Helper functions
- void do_castle(Square kfrom, Square kto, Square rfrom, Square rto);
- template<bool FindPinned> Bitboard hidden_checkers() const;
+ // Other helpers
+ void put_piece(Color c, PieceType pt, Square s);
+ void remove_piece(Color c, PieceType pt, Square s);
+ void move_piece(Color c, PieceType pt, Square from, Square to);
+ template<bool Do>
+ void do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto);
- // Computing hash keys from scratch (for initialization and debugging)
- Key compute_key() const;
- Key compute_pawn_key() const;
- Key compute_material_key() const;
-
- // Computing incremental evaluation scores and material counts
- Score compute_psq_score() const;
- Value compute_non_pawn_material(Color c) const;
-
- // Board and pieces
+ // Data members
Piece board[SQUARE_NB];
Bitboard byTypeBB[PIECE_TYPE_NB];
Bitboard byColorBB[COLOR_NB];
int pieceCount[COLOR_NB][PIECE_TYPE_NB];
Square pieceList[COLOR_NB][PIECE_TYPE_NB][16];
int index[SQUARE_NB];
-
- // Other info
- int castleRightsMask[SQUARE_NB];
- Square castleRookSquare[COLOR_NB][CASTLING_SIDE_NB];
- Bitboard castlePath[COLOR_NB][CASTLING_SIDE_NB];
- StateInfo startState;
- int64_t nodes;
+ int castlingRightsMask[SQUARE_NB];
+ Square castlingRookSquare[CASTLING_RIGHT_NB];
+ Bitboard castlingPath[CASTLING_RIGHT_NB];
+ uint64_t nodes;
int gamePly;
Color sideToMove;
Thread* thisThread;
StateInfo* st;
- int chess960;
+ bool chess960;
};
-inline int64_t Position::nodes_searched() const {
- return nodes;
+extern std::ostream& operator<<(std::ostream& os, const Position& pos);
+
+inline Color Position::side_to_move() const {
+ return sideToMove;
}
-inline void Position::set_nodes_searched(int64_t n) {
- nodes = n;
+inline bool Position::empty(Square s) const {
+ return board[s] == NO_PIECE;
}
inline Piece Position::piece_on(Square s) const {
return board[s];
}
-inline Piece Position::piece_moved(Move m) const {
+inline Piece Position::moved_piece(Move m) const {
return board[from_sq(m)];
}
-inline bool Position::is_empty(Square s) const {
- return board[s] == NO_PIECE;
-}
-
-inline Color Position::side_to_move() const {
- return sideToMove;
-}
-
inline Bitboard Position::pieces() const {
return byTypeBB[ALL_PIECES];
}
return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]);
}
-inline int Position::piece_count(Color c, PieceType pt) const {
- return pieceCount[c][pt];
+template<PieceType Pt> inline int Position::count(Color c) const {
+ return pieceCount[c][Pt];
}
-inline const Square* Position::piece_list(Color c, PieceType pt) const {
- return pieceList[c][pt];
+template<PieceType Pt> inline const Square* Position::squares(Color c) const {
+ return pieceList[c][Pt];
}
-inline Square Position::ep_square() const {
- return st->epSquare;
+template<PieceType Pt> inline Square Position::square(Color c) const {
+ assert(pieceCount[c][Pt] == 1);
+ return pieceList[c][Pt][0];
}
-inline Square Position::king_square(Color c) const {
- return pieceList[c][KING][0];
+inline Square Position::ep_square() const {
+ return st->epSquare;
}
-inline int Position::can_castle(CastleRight f) const {
- return st->castleRights & f;
+inline int Position::can_castle(CastlingRight cr) const {
+ return st->castlingRights & cr;
}
inline int Position::can_castle(Color c) const {
- return st->castleRights & ((WHITE_OO | WHITE_OOO) << (2 * c));
+ return st->castlingRights & ((WHITE_OO | WHITE_OOO) << (2 * c));
}
-inline bool Position::castle_impeded(Color c, CastlingSide s) const {
- return byTypeBB[ALL_PIECES] & castlePath[c][s];
+inline bool Position::castling_impeded(CastlingRight cr) const {
+ return byTypeBB[ALL_PIECES] & castlingPath[cr];
}
-inline Square Position::castle_rook_square(Color c, CastlingSide s) const {
- return castleRookSquare[c][s];
+inline Square Position::castling_rook_square(CastlingRight cr) const {
+ return castlingRookSquare[cr];
}
template<PieceType Pt>
inline Bitboard Position::attacks_from(Square s) const {
-
- return Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, pieces())
+ return Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, byTypeBB[ALL_PIECES])
: Pt == QUEEN ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
: StepAttacksBB[Pt][s];
}
return StepAttacksBB[make_piece(c, PAWN)][s];
}
-inline Bitboard Position::attacks_from(Piece p, Square s) const {
- return attacks_from(p, s, byTypeBB[ALL_PIECES]);
+inline Bitboard Position::attacks_from(Piece pc, Square s) const {
+ return attacks_bb(pc, s, byTypeBB[ALL_PIECES]);
}
inline Bitboard Position::attackers_to(Square s) const {
}
inline Bitboard Position::discovered_check_candidates() const {
- return hidden_checkers<false>();
+ return slider_blockers(pieces(sideToMove), pieces(sideToMove), square<KING>(~sideToMove));
}
-inline Bitboard Position::pinned_pieces() const {
- return hidden_checkers<true>();
+inline Bitboard Position::pinned_pieces(Color c) const {
+ return slider_blockers(pieces(c), pieces(~c), square<KING>(c));
}
-inline bool Position::pawn_is_passed(Color c, Square s) const {
+inline bool Position::pawn_passed(Color c, Square s) const {
return !(pieces(~c, PAWN) & passed_pawn_mask(c, s));
}
-inline Key Position::key() const {
- return st->key;
+inline bool Position::advanced_pawn_push(Move m) const {
+ return type_of(moved_piece(m)) == PAWN
+ && relative_rank(sideToMove, from_sq(m)) > RANK_4;
}
-inline Key Position::exclusion_key() const {
- return st->key ^ Zobrist::exclusion;
+inline Key Position::key() const {
+ return st->key;
}
inline Key Position::pawn_key() const {
return st->materialKey;
}
-inline Score Position::psq_delta(Piece p, Square from, Square to) const {
- return pieceSquareTable[p][to] - pieceSquareTable[p][from];
-}
-
inline Score Position::psq_score() const {
- return st->psqScore;
+ return st->psq;
}
inline Value Position::non_pawn_material(Color c) const {
- return st->npMaterial[c];
-}
-
-inline bool Position::is_passed_pawn_push(Move m) const {
-
- return type_of(piece_moved(m)) == PAWN
- && pawn_is_passed(sideToMove, to_sq(m));
+ return st->nonPawnMaterial[c];
}
inline int Position::game_ply() const {
return gamePly;
}
-inline bool Position::opposite_bishops() const {
-
- return pieceCount[WHITE][BISHOP] == 1
- && pieceCount[BLACK][BISHOP] == 1
- && opposite_colors(pieceList[WHITE][BISHOP][0], pieceList[BLACK][BISHOP][0]);
+inline int Position::rule50_count() const {
+ return st->rule50;
}
-inline bool Position::bishop_pair(Color c) const {
+inline uint64_t Position::nodes_searched() const {
+ return nodes;
+}
- return pieceCount[c][BISHOP] >= 2
- && opposite_colors(pieceList[c][BISHOP][0], pieceList[c][BISHOP][1]);
+inline void Position::set_nodes_searched(uint64_t n) {
+ nodes = n;
}
-inline bool Position::pawn_on_7th(Color c) const {
- return pieces(c, PAWN) & rank_bb(relative_rank(c, RANK_7));
+inline bool Position::opposite_bishops() const {
+ return pieceCount[WHITE][BISHOP] == 1
+ && pieceCount[BLACK][BISHOP] == 1
+ && opposite_colors(square<BISHOP>(WHITE), square<BISHOP>(BLACK));
}
inline bool Position::is_chess960() const {
return chess960;
}
-inline bool Position::is_capture_or_promotion(Move m) const {
+inline bool Position::capture_or_promotion(Move m) const {
assert(is_ok(m));
- return type_of(m) ? type_of(m) != CASTLE : !is_empty(to_sq(m));
+ return type_of(m) != NORMAL ? type_of(m) != CASTLING : !empty(to_sq(m));
}
-inline bool Position::is_capture(Move m) const {
+inline bool Position::capture(Move m) const {
- // Note that castle is coded as "king captures the rook"
+ // Castling is encoded as "king captures the rook"
assert(is_ok(m));
- return (!is_empty(to_sq(m)) && type_of(m) != CASTLE) || type_of(m) == ENPASSANT;
+ return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == ENPASSANT;
}
inline PieceType Position::captured_piece_type() const {
return thisThread;
}
-#endif // !defined(POSITION_H_INCLUDED)
+inline void Position::put_piece(Color c, PieceType pt, Square s) {
+
+ board[s] = make_piece(c, pt);
+ byTypeBB[ALL_PIECES] |= s;
+ byTypeBB[pt] |= s;
+ byColorBB[c] |= s;
+ index[s] = pieceCount[c][pt]++;
+ pieceList[c][pt][index[s]] = s;
+ pieceCount[c][ALL_PIECES]++;
+}
+
+inline void Position::remove_piece(Color c, PieceType pt, Square s) {
+
+ // WARNING: This is not a reversible operation. If we remove a piece in
+ // do_move() and then replace it in undo_move() we will put it at the end of
+ // the list and not in its original place, it means index[] and pieceList[]
+ // are not guaranteed to be invariant to a do_move() + undo_move() sequence.
+ byTypeBB[ALL_PIECES] ^= s;
+ byTypeBB[pt] ^= s;
+ byColorBB[c] ^= s;
+ /* board[s] = NO_PIECE; Not needed, overwritten by the capturing one */
+ Square lastSquare = pieceList[c][pt][--pieceCount[c][pt]];
+ index[lastSquare] = index[s];
+ pieceList[c][pt][index[lastSquare]] = lastSquare;
+ pieceList[c][pt][pieceCount[c][pt]] = SQ_NONE;
+ pieceCount[c][ALL_PIECES]--;
+}
+
+inline void Position::move_piece(Color c, PieceType pt, Square from, Square to) {
+
+ // index[from] is not updated and becomes stale. This works as long as index[]
+ // is accessed just by known occupied squares.
+ Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to];
+ byTypeBB[ALL_PIECES] ^= from_to_bb;
+ byTypeBB[pt] ^= from_to_bb;
+ byColorBB[c] ^= from_to_bb;
+ board[from] = NO_PIECE;
+ board[to] = make_piece(c, pt);
+ index[to] = index[from];
+ pieceList[c][pt][index[to]] = to;
+}
+
+#endif // #ifndef POSITION_H_INCLUDED
projects / stockfish / blobdiff