X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.h;h=d94ef185ac9c45a47de27148ce34f8dfe0ff3685;hp=8fc62c9894d614af730d9e2d405a9da991362d0d;hb=b54bcfddaa2a5f6c5d4d5b54243a682a098f49a3;hpb=db05b1f9f576e80373ca73899df21226fcb4ac8d diff --git a/src/position.h b/src/position.h index 8fc62c98..d94ef185 100644 --- a/src/position.h +++ b/src/position.h @@ -1,7 +1,8 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2019 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 @@ -21,69 +22,64 @@ #define POSITION_H_INCLUDED #include -#include +#include +#include // For std::unique_ptr +#include #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; - -struct CheckInfo { - - explicit CheckInfo(const Position&); - - Bitboard dcCandidates; - Bitboard pinned; - Bitboard checkSq[PIECE_TYPE_NB]; - Square ksq; -}; - - -/// The 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 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 castlingFlags, rule50, pliesFromNull; - Score psq; + + // Copied when making a move + Key pawnKey; + Key materialKey; + Value nonPawnMaterial[COLOR_NB]; + int castlingRights; + int rule50; + int pliesFromNull; Square epSquare; - Key key; - Bitboard checkersBB; - PieceType capturedType; + // Not copied when making a move (will be recomputed anyhow) + Key key; + Bitboard checkersBB; + Piece capturedPiece; StateInfo* previous; + Bitboard blockersForKing[COLOR_NB]; + Bitboard pinners[COLOR_NB]; + Bitboard checkSquares[PIECE_TYPE_NB]; }; +/// A list to keep track of the position states along the setup moves (from the +/// start position to the position just before the search starts). Needed by +/// 'draw by repetition' detection. Use a std::deque because pointers to +/// elements are not invalidated upon list resizing. +typedef std::unique_ptr> 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 class stores the information regarding the board representation -/// like pieces, side to move, hash keys, castling info, etc. The most important -/// methods are do_move() and undo_move(), used by the search to update node info -/// when traversing the search tree. +/// 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 Thread; 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& fenStr, 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); + Position& set(const std::string& code, Color c, StateInfo* si); const std::string fen() const; - const std::string pretty(Move m = MOVE_NONE) const; // Position representation Bitboard pieces() const; @@ -93,128 +89,122 @@ public: 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 empty(Square s) const; template int count(Color c) const; - template const Square* list(Color c) const; + template int count() const; + template const Square* squares(Color c) const; + template Square square(Color c) const; // Castling - int can_castle(CastlingFlag f) const; - int can_castle(Color c) const; - bool castling_impeded(Color c, CastlingSide s) const; - Square castling_rook_square(Color c, CastlingSide s) const; + int castling_rights(Color c) const; + bool 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(Color c) const; + Bitboard blockers_for_king(Color c) const; + Bitboard check_squares(PieceType pt) 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; + Bitboard attackers_to(Square s, Bitboard occupied) const; + Bitboard attacks_from(PieceType pt, Square s) const; template Bitboard attacks_from(Square s) const; template Bitboard attacks_from(Square s, Color c) const; + Bitboard slider_blockers(Bitboard sliders, Square s, Bitboard& pinners) const; // Properties of moves - bool legal(Move m, Bitboard pinned) const; + bool legal(Move m) 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 gives_check(Move m) const; bool advanced_pawn_push(Move m) const; Piece moved_piece(Move m) const; - PieceType captured_piece_type() const; + Piece captured_piece() const; // Piece specific bool pawn_passed(Color c, Square s) const; - bool pawn_on_7th(Color c) const; - bool bishop_pair(Color c) const; bool opposite_bishops() 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& newSt); + void do_move(Move m, StateInfo& newSt, bool givesCheck); void undo_move(Move m); - void do_null_move(StateInfo& st); + void do_null_move(StateInfo& newSt); void undo_null_move(); - // Static exchange evaluation - int see(Move m) const; - int see_sign(Move m) const; + // Static Exchange Evaluation + bool see_ge(Move m, Value threshold = VALUE_ZERO) const; // Accessing hash keys Key key() const; - Key exclusion_key() const; - Key pawn_key() const; + Key key_after(Move m) const; Key material_key() const; - - // Incremental piece-square evaluation - Score psq_score() const; - Value non_pawn_material(Color c) const; + Key pawn_key() const; // Other properties of the position Color side_to_move() 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); - bool is_draw() const; + bool is_draw(int ply) const; + bool has_game_cycle(int ply) const; + bool has_repeated() const; + int rule50_count() const; + Score psq_score() const; + Value non_pawn_material(Color c) const; + Value non_pawn_material() const; // Position consistency check, for debugging - bool pos_is_ok(int* failedStep = NULL) const; + bool pos_is_ok() const; void flip(); private: // Initialization helpers (used while setting up a position) - void clear(); - void set_castling_flag(Color c, Square rfrom); - - // Helper functions - void do_castling(Square kfrom, Square kto, Square rfrom, Square rto); - Bitboard check_blockers(Color c, Color kingColor) const; - void put_piece(Square s, Color c, PieceType pt); - void remove_piece(Square s, Color c, PieceType pt); - void move_piece(Square from, Square to, Color c, PieceType pt); - - // 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 + void set_castling_right(Color c, Square rfrom); + void set_state(StateInfo* si) const; + void set_check_info(StateInfo* si) const; + + // Other helpers + void put_piece(Piece pc, Square s); + void remove_piece(Piece pc, Square s); + void move_piece(Piece pc, Square from, Square to); + template + void do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto); + + // 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 pieceCount[PIECE_NB]; + Square pieceList[PIECE_NB][16]; int index[SQUARE_NB]; - - // Other info - int castlingFlagsMask[SQUARE_NB]; - Square castlingRookSquare[COLOR_NB][CASTLING_SIDE_NB]; - Bitboard castlingPath[COLOR_NB][CASTLING_SIDE_NB]; - StateInfo startState; - int64_t nodes; + int castlingRightsMask[SQUARE_NB]; + Square castlingRookSquare[CASTLING_RIGHT_NB]; + Bitboard castlingPath[CASTLING_RIGHT_NB]; int gamePly; Color sideToMove; + Score psq; Thread* thisThread; StateInfo* st; - int chess960; + bool chess960; }; -inline int64_t Position::nodes_searched() const { - return nodes; +namespace PSQT { + extern Score psq[PIECE_NB][SQUARE_NB]; +} + +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 { @@ -225,14 +215,6 @@ inline Piece Position::moved_piece(Move m) const { return board[from_sq(m)]; } -inline bool Position::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]; } @@ -258,52 +240,57 @@ inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const { } template inline int Position::count(Color c) const { - return pieceCount[c][Pt]; + return pieceCount[make_piece(c, Pt)]; } -template inline const Square* Position::list(Color c) const { - return pieceList[c][Pt]; +template inline int Position::count() const { + return pieceCount[make_piece(WHITE, Pt)] + pieceCount[make_piece(BLACK, Pt)]; } -inline Square Position::ep_square() const { - return st->epSquare; +template inline const Square* Position::squares(Color c) const { + return pieceList[make_piece(c, Pt)]; } -inline Square Position::king_square(Color c) const { - return pieceList[c][KING][0]; +template inline Square Position::square(Color c) const { + assert(pieceCount[make_piece(c, Pt)] == 1); + return pieceList[make_piece(c, Pt)][0]; +} + +inline Square Position::ep_square() const { + return st->epSquare; } -inline int Position::can_castle(CastlingFlag f) const { - return st->castlingFlags & f; +inline bool Position::can_castle(CastlingRight cr) const { + return st->castlingRights & cr; } -inline int Position::can_castle(Color c) const { - return st->castlingFlags & ((WHITE_OO | WHITE_OOO) << (2 * c)); +inline int Position::castling_rights(Color c) const { + return st->castlingRights & ((WHITE_OO | WHITE_OOO) << (2 * c)); } -inline bool Position::castling_impeded(Color c, CastlingSide s) const { - return byTypeBB[ALL_PIECES] & castlingPath[c][s]; +inline bool Position::castling_impeded(CastlingRight cr) const { + return byTypeBB[ALL_PIECES] & castlingPath[cr]; } -inline Square Position::castling_rook_square(Color c, CastlingSide s) const { - return castlingRookSquare[c][s]; +inline Square Position::castling_rook_square(CastlingRight cr) const { + return castlingRookSquare[cr]; } template inline Bitboard Position::attacks_from(Square s) const { - - return Pt == BISHOP || Pt == ROOK ? attacks_bb(s, pieces()) + assert(Pt != PAWN); + return Pt == BISHOP || Pt == ROOK ? attacks_bb(s, byTypeBB[ALL_PIECES]) : Pt == QUEEN ? attacks_from(s) | attacks_from(s) - : StepAttacksBB[Pt][s]; + : PseudoAttacks[Pt][s]; } template<> inline Bitboard Position::attacks_from(Square s, Color c) const { - return StepAttacksBB[make_piece(c, PAWN)][s]; + return PawnAttacks[c][s]; } -inline Bitboard Position::attacks_from(Piece p, Square s) const { - return attacks_bb(p, s, byTypeBB[ALL_PIECES]); +inline Bitboard Position::attacks_from(PieceType pt, Square s) const { + return attacks_bb(pt, s, byTypeBB[ALL_PIECES]); } inline Bitboard Position::attackers_to(Square s) const { @@ -314,12 +301,12 @@ inline Bitboard Position::checkers() const { return st->checkersBB; } -inline Bitboard Position::discovered_check_candidates() const { - return check_blockers(sideToMove, ~sideToMove); +inline Bitboard Position::blockers_for_king(Color c) const { + return st->blockersForKing[c]; } -inline Bitboard Position::pinned_pieces(Color c) const { - return check_blockers(c, c); +inline Bitboard Position::check_squares(PieceType pt) const { + return st->checkSquares[pt]; } inline bool Position::pawn_passed(Color c, Square s) const { @@ -344,32 +331,29 @@ inline Key Position::material_key() const { } inline Score Position::psq_score() const { - return st->psq; + return psq; } inline Value Position::non_pawn_material(Color c) const { - return st->npMaterial[c]; + return st->nonPawnMaterial[c]; } -inline int Position::game_ply() const { - return gamePly; +inline Value Position::non_pawn_material() const { + return st->nonPawnMaterial[WHITE] + st->nonPawnMaterial[BLACK]; } -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::game_ply() const { + return gamePly; } -inline bool Position::bishop_pair(Color c) const { - - return pieceCount[c][BISHOP] >= 2 - && opposite_colors(pieceList[c][BISHOP][0], pieceList[c][BISHOP][1]); +inline int Position::rule50_count() const { + return st->rule50; } -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[W_BISHOP] == 1 + && pieceCount[B_BISHOP] == 1 + && opposite_colors(square(WHITE), square(BLACK)); } inline bool Position::is_chess960() const { @@ -377,66 +361,71 @@ inline bool Position::is_chess960() const { } inline bool Position::capture_or_promotion(Move m) const { - assert(is_ok(m)); return type_of(m) != NORMAL ? type_of(m) != CASTLING : !empty(to_sq(m)); } inline bool Position::capture(Move m) const { - - // Note that castling is encoded as "king captures the rook" assert(is_ok(m)); + // Castling is encoded as "king captures rook" return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == ENPASSANT; } -inline PieceType Position::captured_piece_type() const { - return st->capturedType; +inline Piece Position::captured_piece() const { + return st->capturedPiece; } inline Thread* Position::this_thread() const { return thisThread; } -inline void Position::put_piece(Square s, Color c, PieceType pt) { +inline void Position::put_piece(Piece pc, Square s) { - board[s] = make_piece(c, pt); + board[s] = pc; byTypeBB[ALL_PIECES] |= s; - byTypeBB[pt] |= s; - byColorBB[c] |= s; - pieceCount[c][ALL_PIECES]++; - index[s] = pieceCount[c][pt]++; - pieceList[c][pt][index[s]] = s; -} - -inline void Position::move_piece(Square from, Square to, Color c, PieceType pt) { - - // 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; + byTypeBB[type_of(pc)] |= s; + byColorBB[color_of(pc)] |= s; + index[s] = pieceCount[pc]++; + pieceList[pc][index[s]] = s; + pieceCount[make_piece(color_of(pc), ALL_PIECES)]++; + psq += PSQT::psq[pc][s]; } -inline void Position::remove_piece(Square s, Color c, PieceType pt) { +inline void Position::remove_piece(Piece pc, 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. + // are not invariant to a do_move() + undo_move() sequence. byTypeBB[ALL_PIECES] ^= s; - byTypeBB[pt] ^= s; - byColorBB[c] ^= s; - /* board[s] = NO_PIECE; */ // Not needed, will be overwritten by capturing - pieceCount[c][ALL_PIECES]--; - Square lastSquare = pieceList[c][pt][--pieceCount[c][pt]]; + byTypeBB[type_of(pc)] ^= s; + byColorBB[color_of(pc)] ^= s; + /* board[s] = NO_PIECE; Not needed, overwritten by the capturing one */ + Square lastSquare = pieceList[pc][--pieceCount[pc]]; index[lastSquare] = index[s]; - pieceList[c][pt][index[lastSquare]] = lastSquare; - pieceList[c][pt][pieceCount[c][pt]] = SQ_NONE; + pieceList[pc][index[lastSquare]] = lastSquare; + pieceList[pc][pieceCount[pc]] = SQ_NONE; + pieceCount[make_piece(color_of(pc), ALL_PIECES)]--; + psq -= PSQT::psq[pc][s]; +} + +inline void Position::move_piece(Piece pc, 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 fromTo = SquareBB[from] ^ SquareBB[to]; + byTypeBB[ALL_PIECES] ^= fromTo; + byTypeBB[type_of(pc)] ^= fromTo; + byColorBB[color_of(pc)] ^= fromTo; + board[from] = NO_PIECE; + board[to] = pc; + index[to] = index[from]; + pieceList[pc][index[to]] = to; + psq += PSQT::psq[pc][to] - PSQT::psq[pc][from]; +} + +inline void Position::do_move(Move m, StateInfo& newSt) { + do_move(m, newSt, gives_check(m)); } #endif // #ifndef POSITION_H_INCLUDED