/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, 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
#define POSITION_H_INCLUDED
#include <cassert>
+#include <cstddef>
#include "bitboard.h"
-#include "move.h"
#include "types.h"
-/// Maximum number of plies per game (220 should be enough, because the
-/// maximum search depth is 100, and during position setup we reset the
-/// move counter for every non-reversible move).
-const int MaxGameLength = 220;
+/// The checkInfo struct is initialized at c'tor time and keeps info used
+/// to detect if a move gives check.
class Position;
-
-/// struct checkInfo is initialized at c'tor time and keeps
-/// info used to detect if a move gives check.
+class Thread;
struct CheckInfo {
- explicit CheckInfo(const Position&);
+ explicit CheckInfo(const Position&);
- Bitboard dcCandidates;
- Bitboard checkSq[8];
- Square ksq;
-};
-
-/// Castle rights, encoded as bit fields
-
-enum CastleRights {
- CASTLES_NONE = 0,
- WHITE_OO = 1,
- BLACK_OO = 2,
- WHITE_OOO = 4,
- BLACK_OOO = 8,
- ALL_CASTLES = 15
-};
-
-/// Game phase
-enum Phase {
- PHASE_ENDGAME = 0,
- PHASE_MIDGAME = 128
+ Bitboard dcCandidates;
+ Bitboard pinned;
+ Bitboard checkSq[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), an StateInfo object
+/// is made on the board (by calling Position::do_move), a StateInfo object
/// must be passed as a parameter.
struct StateInfo {
Key pawnKey, materialKey;
- int castleRights, rule50, gamePly, pliesFromNull;
+ Value npMaterial[COLOR_NB];
+ int castleRights, rule50, pliesFromNull;
+ Score psqScore;
Square epSquare;
- Score value;
- Value npMaterial[2];
- PieceType capturedType;
Key key;
Bitboard checkersBB;
+ PieceType capturedType;
StateInfo* previous;
};
+/// 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
/// * A counter for detecting 50 move rule draws.
class Position {
-
- Position(); // No default or copy c'tor allowed
- Position(const Position& pos);
-
public:
- enum GamePhase {
- MidGame,
- EndGame
- };
-
- // Constructors
- Position(const Position& pos, int threadID);
- Position(const std::string& fen, bool isChess960, int threadID);
+ 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&);
// Text input/output
- void from_fen(const std::string& fen, bool isChess960);
- const std::string to_fen() const;
- void print(Move m = MOVE_NONE) const;
+ void set(const std::string& fen, bool isChess960, Thread* th);
+ const std::string fen() const;
+ const std::string pretty(Move m = MOVE_NONE) const;
- // Copying
- void flip();
-
- // The piece on a given square
- Piece piece_on(Square s) const;
- PieceType type_of_piece_on(Square s) const;
- Color color_of_piece_on(Square s) const;
- bool square_is_empty(Square s) const;
- bool square_is_occupied(Square s) const;
- Value midgame_value_of_piece_on(Square s) const;
- Value endgame_value_of_piece_on(Square s) const;
-
- // Side to move
- Color side_to_move() const;
-
- // Bitboard representation of the position
- Bitboard empty_squares() const;
- Bitboard occupied_squares() const;
- Bitboard pieces_of_color(Color c) const;
+ // Position representation
+ Bitboard pieces() const;
Bitboard pieces(PieceType pt) const;
- Bitboard pieces(PieceType pt, Color c) const;
Bitboard pieces(PieceType pt1, PieceType pt2) const;
- Bitboard pieces(PieceType pt1, PieceType pt2, Color c) const;
-
- // Number of pieces of each color and type
- int piece_count(Color c, PieceType pt) const;
-
- // The en passant square
- Square ep_square() const;
-
- // Current king position for each color
+ Bitboard pieces(Color c) 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;
- // Castling rights
- bool can_castle_kingside(Color c) const;
- bool can_castle_queenside(Color c) const;
- bool can_castle(Color c) const;
- Square initial_kr_square(Color c) const;
- Square initial_qr_square(Color c) const;
-
- // Bitboards for pinned pieces and discovered check candidates
- Bitboard discovered_check_candidates(Color c) const;
- Bitboard pinned_pieces(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;
- // Checking pieces and under check information
- Bitboard checkers() const;
+ // Checking
bool in_check() const;
+ Bitboard checkers() const;
+ Bitboard discovered_check_candidates() const;
+ Bitboard pinned_pieces() const;
- // Piece lists
- Square piece_list(Color c, PieceType pt, int index) const;
- const Square* piece_list_begin(Color c, PieceType pt) const;
-
- // Information about attacks to or from a given square
+ // 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);
template<PieceType> Bitboard attacks_from(Square s) const;
template<PieceType> Bitboard attacks_from(Square s, Color c) const;
// Properties of moves
- bool pl_move_is_legal(Move m, Bitboard pinned) const;
- bool pl_move_is_evasion(Move m, Bitboard pinned) const;
- bool move_is_legal(const Move m) const;
- bool move_is_legal(const Move m, Bitboard pinned) const;
- bool move_gives_check(Move m) const;
bool move_gives_check(Move m, const CheckInfo& ci) const;
- bool move_is_capture(Move m) const;
- bool move_is_capture_or_promotion(Move m) const;
- bool move_is_passed_pawn_push(Move m) const;
- bool move_attacks_square(Move m, Square s) const;
-
- // Piece captured with previous moves
+ bool move_is_legal(const Move m) 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;
PieceType captured_piece_type() const;
- // Information about pawns
+ // Piece specific
bool pawn_is_passed(Color c, Square s) const;
-
- // Weak squares
- bool square_is_weak(Square s, Color c) const;
+ bool pawn_on_7th(Color c) const;
+ bool opposite_bishops() const;
+ bool bishop_pair(Color c) const;
// Doing and undoing moves
- void do_setup_move(Move m);
void do_move(Move m, StateInfo& st);
void do_move(Move m, StateInfo& st, const CheckInfo& ci, bool moveIsCheck);
void undo_move(Move m);
- void do_null_move(StateInfo& st);
- void undo_null_move();
+ template<bool Do> void do_null_move(StateInfo& st);
// Static exchange evaluation
int see(Move m) const;
int see_sign(Move m) const;
// Accessing hash keys
- Key get_key() const;
- Key get_exclusion_key() const;
- Key get_pawn_key() const;
- Key get_material_key() const;
-
- // Incremental evaluation
- Score value() const;
+ Key key() 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;
- static Score pst_delta(Piece piece, Square from, Square to);
-
- // Game termination checks
- bool is_mate() const;
- bool is_draw() const;
-
- // Number of plies from starting position
- int startpos_ply_counter() const;
// Other properties of the position
- bool opposite_colored_bishops() const;
- bool has_pawn_on_7th(Color c) const;
+ Color side_to_move() const;
+ int startpos_ply_counter() const;
bool is_chess960() const;
-
- // Current thread ID searching on the position
- int thread() const;
-
+ Thread* this_thread() const;
int64_t nodes_searched() const;
void set_nodes_searched(int64_t n);
+ template<bool CheckRepetition, bool CheckThreeFold> bool is_draw() const;
// Position consistency check, for debugging
- bool is_ok(int* failedStep = NULL) const;
-
- // Static member functions
- static void init_zobrist();
- static void init_piece_square_tables();
+ bool pos_is_ok(int* failedStep = NULL) const;
+ void flip();
private:
-
- // Initialization helper functions (used while setting up a position)
+ // Initialization helpers (used while setting up a position)
void clear();
- void detach();
void put_piece(Piece p, Square s);
- void do_allow_oo(Color c);
- void do_allow_ooo(Color c);
- bool set_castling_rights(char token);
+ void set_castle_right(Color c, Square rfrom);
- // Helper functions for doing and undoing moves
- void do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep);
- void do_castle_move(Move m);
- void undo_castle_move(Move m);
- void find_checkers();
-
- template<bool FindPinned>
- Bitboard hidden_checkers(Color c) const;
+ // Helper template functions
+ template<bool Do> void do_castle_move(Move m);
+ template<bool FindPinned> Bitboard hidden_checkers() const;
// Computing hash keys from scratch (for initialization and debugging)
Key compute_key() const;
Key compute_material_key() const;
// Computing incremental evaluation scores and material counts
- static Score pst(Color c, PieceType pt, Square s);
- Score compute_value() const;
+ Score compute_psq_score() const;
Value compute_non_pawn_material(Color c) const;
- // Board
- Piece board[64];
-
- // Bitboards
- Bitboard byTypeBB[8], byColorBB[2];
-
- // Piece counts
- int pieceCount[2][8]; // [color][pieceType]
-
- // Piece lists
- Square pieceList[2][8][16]; // [color][pieceType][index]
- int index[64]; // [square]
+ // Board and pieces
+ 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
- Color sideToMove;
- Key history[MaxGameLength];
- int castleRightsMask[64];
+ int castleRightsMask[SQUARE_NB];
+ Square castleRookSquare[COLOR_NB][CASTLING_SIDE_NB];
+ Bitboard castlePath[COLOR_NB][CASTLING_SIDE_NB];
StateInfo startState;
- File initialKFile, initialKRFile, initialQRFile;
- bool chess960;
- int startPosPlyCounter;
- int threadID;
int64_t nodes;
+ int startPosPly;
+ Color sideToMove;
+ Thread* thisThread;
StateInfo* st;
-
- // Static variables
- static Key zobrist[2][8][64];
- static Key zobEp[64];
- static Key zobCastle[16];
- static Key zobSideToMove;
- static Score PieceSquareTable[16][64];
- static Key zobExclusion;
- static const Value seeValues[8];
- static const Value PieceValueMidgame[17];
- static const Value PieceValueEndgame[17];
+ int chess960;
};
inline int64_t Position::nodes_searched() const {
return board[s];
}
-inline Color Position::color_of_piece_on(Square s) const {
- return color_of_piece(piece_on(s));
+inline Piece Position::piece_moved(Move m) const {
+ return board[from_sq(m)];
}
-inline PieceType Position::type_of_piece_on(Square s) const {
- return type_of_piece(piece_on(s));
-}
-
-inline bool Position::square_is_empty(Square s) const {
- return piece_on(s) == PIECE_NONE;
-}
-
-inline bool Position::square_is_occupied(Square s) const {
- return !square_is_empty(s);
-}
-
-inline Value Position::midgame_value_of_piece_on(Square s) const {
- return PieceValueMidgame[piece_on(s)];
-}
-
-inline Value Position::endgame_value_of_piece_on(Square s) const {
- return PieceValueEndgame[piece_on(s)];
+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::occupied_squares() const {
- return byTypeBB[0];
-}
-
-inline Bitboard Position::empty_squares() const {
- return ~occupied_squares();
-}
-
-inline Bitboard Position::pieces_of_color(Color c) const {
- return byColorBB[c];
+inline Bitboard Position::pieces() const {
+ return byTypeBB[ALL_PIECES];
}
inline Bitboard Position::pieces(PieceType pt) const {
return byTypeBB[pt];
}
-inline Bitboard Position::pieces(PieceType pt, Color c) const {
- return byTypeBB[pt] & byColorBB[c];
-}
-
inline Bitboard Position::pieces(PieceType pt1, PieceType pt2) const {
return byTypeBB[pt1] | byTypeBB[pt2];
}
-inline Bitboard Position::pieces(PieceType pt1, PieceType pt2, Color c) const {
- return (byTypeBB[pt1] | byTypeBB[pt2]) & byColorBB[c];
+inline Bitboard Position::pieces(Color c) const {
+ return byColorBB[c];
}
-inline int Position::piece_count(Color c, PieceType pt) const {
- return pieceCount[c][pt];
+inline Bitboard Position::pieces(Color c, PieceType pt) const {
+ return byColorBB[c] & byTypeBB[pt];
}
-inline Square Position::piece_list(Color c, PieceType pt, int idx) const {
- return pieceList[c][pt][idx];
+inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const {
+ return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]);
}
-inline const Square* Position::piece_list_begin(Color c, PieceType pt) const {
+inline int Position::piece_count(Color c, PieceType pt) const {
+ return pieceCount[c][pt];
+}
+
+inline const Square* Position::piece_list(Color c, PieceType pt) const {
return pieceList[c][pt];
}
return pieceList[c][KING][0];
}
-inline bool Position::can_castle_kingside(Color side) const {
- return st->castleRights & (1+int(side));
+inline int Position::can_castle(CastleRight f) const {
+ return st->castleRights & f;
}
-inline bool Position::can_castle_queenside(Color side) const {
- return st->castleRights & (4+4*int(side));
+inline int Position::can_castle(Color c) const {
+ return st->castleRights & ((WHITE_OO | WHITE_OOO) << (2 * c));
}
-inline bool Position::can_castle(Color side) const {
- return can_castle_kingside(side) || can_castle_queenside(side);
+inline bool Position::castle_impeded(Color c, CastlingSide s) const {
+ return byTypeBB[ALL_PIECES] & castlePath[c][s];
}
-inline Square Position::initial_kr_square(Color c) const {
- return relative_square(c, make_square(initialKRFile, RANK_1));
+inline Square Position::castle_rook_square(Color c, CastlingSide s) const {
+ return castleRookSquare[c][s];
}
-inline Square Position::initial_qr_square(Color c) const {
- return relative_square(c, make_square(initialQRFile, RANK_1));
+template<PieceType Pt>
+inline Bitboard Position::attacks_from(Square s) const {
+
+ return Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, pieces())
+ : Pt == QUEEN ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
+ : StepAttacksBB[Pt][s];
}
template<>
return StepAttacksBB[make_piece(c, PAWN)][s];
}
-template<PieceType Piece> // Knight and King and white pawns
-inline Bitboard Position::attacks_from(Square s) const {
- return StepAttacksBB[Piece][s];
-}
-
-template<>
-inline Bitboard Position::attacks_from<BISHOP>(Square s) const {
- return bishop_attacks_bb(s, occupied_squares());
-}
-
-template<>
-inline Bitboard Position::attacks_from<ROOK>(Square s) const {
- return rook_attacks_bb(s, occupied_squares());
+inline Bitboard Position::attacks_from(Piece p, Square s) const {
+ return attacks_from(p, s, byTypeBB[ALL_PIECES]);
}
-template<>
-inline Bitboard Position::attacks_from<QUEEN>(Square s) const {
- return attacks_from<ROOK>(s) | attacks_from<BISHOP>(s);
+inline Bitboard Position::attackers_to(Square s) const {
+ return attackers_to(s, byTypeBB[ALL_PIECES]);
}
inline Bitboard Position::checkers() const {
}
inline bool Position::in_check() const {
- return st->checkersBB != EmptyBoardBB;
+ return st->checkersBB != 0;
}
-inline bool Position::pawn_is_passed(Color c, Square s) const {
- return !(pieces(PAWN, opposite_color(c)) & passed_pawn_mask(c, s));
+inline Bitboard Position::discovered_check_candidates() const {
+ return hidden_checkers<false>();
}
-inline bool Position::square_is_weak(Square s, Color c) const {
- return !(pieces(PAWN, opposite_color(c)) & attack_span_mask(c, s));
+inline Bitboard Position::pinned_pieces() const {
+ return hidden_checkers<true>();
}
-inline Key Position::get_key() const {
+inline bool Position::pawn_is_passed(Color c, Square s) const {
+ return !(pieces(~c, PAWN) & passed_pawn_mask(c, s));
+}
+
+inline Key Position::key() const {
return st->key;
}
-inline Key Position::get_exclusion_key() const {
- return st->key ^ zobExclusion;
+inline Key Position::exclusion_key() const {
+ return st->key ^ Zobrist::exclusion;
}
-inline Key Position::get_pawn_key() const {
+inline Key Position::pawn_key() const {
return st->pawnKey;
}
-inline Key Position::get_material_key() const {
+inline Key Position::material_key() const {
return st->materialKey;
}
-inline Score Position::pst(Color c, PieceType pt, Square s) {
- return PieceSquareTable[make_piece(c, pt)][s];
+inline Score Position::psq_delta(Piece p, Square from, Square to) const {
+ return pieceSquareTable[p][to] - pieceSquareTable[p][from];
}
-inline Score Position::pst_delta(Piece piece, Square from, Square to) {
- return PieceSquareTable[piece][to] - PieceSquareTable[piece][from];
-}
-
-inline Score Position::value() const {
- return st->value;
+inline Score Position::psq_score() const {
+ return st->psqScore;
}
inline Value Position::non_pawn_material(Color c) const {
return st->npMaterial[c];
}
-inline bool Position::move_is_passed_pawn_push(Move m) const {
+inline bool Position::is_passed_pawn_push(Move m) const {
- Color c = side_to_move();
- return piece_on(move_from(m)) == make_piece(c, PAWN)
- && pawn_is_passed(c, move_to(m));
+ return type_of(piece_moved(m)) == PAWN
+ && pawn_is_passed(sideToMove, to_sq(m));
}
inline int Position::startpos_ply_counter() const {
- return startPosPlyCounter;
+ return startPosPly + st->pliesFromNull; // HACK
+}
+
+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 bool Position::opposite_colored_bishops() const {
+inline bool Position::bishop_pair(Color c) const {
- return piece_count(WHITE, BISHOP) == 1 && piece_count(BLACK, BISHOP) == 1
- && opposite_color_squares(piece_list(WHITE, BISHOP, 0), piece_list(BLACK, BISHOP, 0));
+ return pieceCount[c][BISHOP] >= 2
+ && opposite_colors(pieceList[c][BISHOP][0], pieceList[c][BISHOP][1]);
}
-inline bool Position::has_pawn_on_7th(Color c) const {
- return pieces(PAWN, c) & rank_bb(relative_rank(c, RANK_7));
+inline bool Position::pawn_on_7th(Color c) const {
+ return pieces(c, PAWN) & rank_bb(relative_rank(c, RANK_7));
}
inline bool Position::is_chess960() const {
return chess960;
}
-inline bool Position::move_is_capture(Move m) const {
+inline bool Position::is_capture_or_promotion(Move m) const {
- assert (m != MOVE_NONE && m != MOVE_NULL);
- return (m & (3 << 15)) ? !move_is_castle(m) : !square_is_empty(move_to(m));
+ assert(is_ok(m));
+ return type_of(m) ? type_of(m) != CASTLE : !is_empty(to_sq(m));
}
-inline bool Position::move_is_capture_or_promotion(Move m) const {
+inline bool Position::is_capture(Move m) const {
- assert (m != MOVE_NONE && m != MOVE_NULL);
- return (m & (0x1F << 12)) ? !move_is_castle(m) : !square_is_empty(move_to(m));
+ // Note that castle is coded as "king captures the rook"
+ assert(is_ok(m));
+ return (!is_empty(to_sq(m)) && type_of(m) != CASTLE) || type_of(m) == ENPASSANT;
}
inline PieceType Position::captured_piece_type() const {
return st->capturedType;
}
-inline int Position::thread() const {
- return threadID;
-}
-
-inline void Position::do_allow_oo(Color c) {
- st->castleRights |= (1 + int(c));
-}
-
-inline void Position::do_allow_ooo(Color c) {
- st->castleRights |= (4 + 4*int(c));
+inline Thread* Position::this_thread() const {
+ return thisThread;
}
#endif // !defined(POSITION_H_INCLUDED)
projects / stockfish / blobdiff