X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.h;h=8d3393faaa18b20c0fdbcafba1a7a3cee8c25fb5;hp=eec8ff7494df11a72c5d376b693d98193165c57c;hb=4ae5a7b45a430aea5f4b21f9455b4db74ed1c44a;hpb=782c3f36ccd4aeb52fd7eb92590d5e5e48741eaa diff --git a/src/position.h b/src/position.h index eec8ff74..2106414b 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) 2008-2010 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 @@ -17,448 +18,430 @@ along with this program. If not, see . */ -#if !defined(POSITION_H_INCLUDED) +#ifndef POSITION_H_INCLUDED #define POSITION_H_INCLUDED #include +#include +#include // For std::unique_ptr +#include #include "bitboard.h" -#include "move.h" #include "types.h" -/// The checkInfo struct is initialized at c'tor time and keeps info used -/// to detect if a move gives check. - -struct CheckInfo { - - explicit CheckInfo(const Position&); - - Bitboard dcCandidates; - Bitboard pinned; - Bitboard checkSq[8]; -}; - - -/// 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 -/// must be passed as a parameter. -class Position; +/// 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[2]; - int castleRights, rule50, pliesFromNull; - Score value; + + // 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) + int repetition; + 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; -/// 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. -class Position { - - // No defaul, copy c'tor or assignment allowed, default c'tor will not be - // generated anyhow because of user-defined c'tors. - Position(const Position&); - Position& operator=(const Position&); +/// 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(const Position& pos, int threadID); - Position(const std::string& fen, bool isChess960, int threadID); + static void init(); - // 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; + Position() = default; + Position(const Position&) = delete; + Position& operator=(const Position&) = delete; - // The piece on a given square - Piece piece_on(Square s) const; - bool square_is_empty(Square s) const; + // 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; - // Side to move - Color side_to_move() const; - - // Bitboard representation of the position - Bitboard empty_squares() const; - Bitboard occupied_squares() const; - Bitboard pieces(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 + 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 ep_square() const; - - // Current king position for each color - Square king_square(Color c) const; - - // Castling rights - bool can_castle(CastleRight f) const; - bool can_castle(Color c) const; - Square castle_rook_square(CastleRight f) const; - - // Bitboards for pinned pieces and discovered check candidates - Bitboard discovered_check_candidates() const; - Bitboard pinned_pieces() const; - - // Checking pieces and under check information + bool empty(Square s) const; + template int count(Color c) const; + template int count() const; + template const Square* squares(Color c) const; + template Square square(Color c) const; + bool is_on_semiopen_file(Color c, Square s) const; + + // Castling + 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; - bool in_check() const; + Bitboard blockers_for_king(Color c) const; + Bitboard check_squares(PieceType pt) const; + bool is_discovery_check_on_king(Color c, Move m) const; - // Piece lists - const Square* piece_list(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); + 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 move_gives_check(Move m, const CheckInfo& ci) const; - bool move_attacks_square(Move m, Square s) 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 captured with previous moves - PieceType captured_piece_type() const; - - // Information about pawns - bool pawn_is_passed(Color c, Square s) 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; + bool advanced_pawn_push(Move m) const; + Piece moved_piece(Move m) const; + Piece captured_piece() const; + + // Piece specific + bool pawn_passed(Color c, Square s) const; + bool opposite_bishops() const; + int pawns_on_same_color_squares(Color c, Square s) 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 get_key() const; - Key get_exclusion_key() const; - Key get_pawn_key() const; - Key get_material_key() const; - - // Incremental evaluation - Score value() const; - Value non_pawn_material(Color c) const; - Score pst_delta(Piece piece, Square from, Square to) const; - - // Game termination checks - bool is_mate() const; - template bool is_draw() const; - - // Plies from start position to the beginning of search - int startpos_ply_counter() const; + Key key() const; + Key key_after(Move m) const; + Key material_key() const; + Key pawn_key() 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 game_ply() const; bool is_chess960() const; - - // Current thread ID searching on the position - int thread() const; - - int64_t nodes_searched() const; - void set_nodes_searched(int64_t n); + Thread* this_thread() 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; - void flip_me(); - - // Global initialization - static void init(); + bool pos_is_ok() const; + void flip(); private: - - // Initialization helper functions (used while setting up a position) - void clear(); - void put_piece(Piece p, Square s); - void set_castle(int f, Square ksq, Square rsq); - void set_castling_rights(char token); - bool move_is_legal(const Move m) const; - - // 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); - - template - Bitboard hidden_checkers() const; - - // 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 pst(Piece p, Square s) const; - Score compute_value() const; - Value compute_non_pawn_material(Color c) const; - - // Board - Piece board[64]; // [square] - - // Bitboards - Bitboard byTypeBB[8]; // [pieceType] - Bitboard byColorBB[2]; // [color] - - // Piece counts - int pieceCount[2][8]; // [color][pieceType] - - // Piece lists - Square pieceList[2][8][16]; // [color][pieceType][index] - int index[64]; // [square] - - // Other info - int castleRightsMask[64]; // [square] - Square castleRookSquare[16]; // [castleRight] - StateInfo startState; - int64_t nodes; - int startPosPly; + // Initialization helpers (used while setting up a position) + 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[PIECE_NB]; + Square pieceList[PIECE_NB][16]; + int index[SQUARE_NB]; + int castlingRightsMask[SQUARE_NB]; + Square castlingRookSquare[CASTLING_RIGHT_NB]; + Bitboard castlingPath[CASTLING_RIGHT_NB]; + int gamePly; Color sideToMove; - int threadID; + Score psq; + Thread* thisThread; StateInfo* st; - int chess960; - - // Static variables - static Score pieceSquareTable[16][64]; // [piece][square] - static Key zobrist[2][8][64]; // [color][pieceType][square] - static Key zobEp[64]; // [square] - static Key zobCastle[16]; // [castleRight] - static Key zobSideToMove; - static Key zobExclusion; + 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 { return board[s]; } -inline bool Position::square_is_empty(Square s) const { - return board[s] == PIECE_NONE; +inline Piece Position::moved_piece(Move m) const { + return board[from_sq(m)]; } -inline Color Position::side_to_move() const { - return sideToMove; +inline Bitboard Position::pieces() const { + return byTypeBB[ALL_PIECES]; } -inline Bitboard Position::occupied_squares() const { - return byTypeBB[0]; +inline Bitboard Position::pieces(PieceType pt) const { + return byTypeBB[pt]; } -inline Bitboard Position::empty_squares() const { - return ~byTypeBB[0]; +inline Bitboard Position::pieces(PieceType pt1, PieceType pt2) const { + return byTypeBB[pt1] | byTypeBB[pt2]; } inline Bitboard Position::pieces(Color c) const { return byColorBB[c]; } -inline Bitboard Position::pieces(PieceType pt) const { - return byTypeBB[pt]; +inline Bitboard Position::pieces(Color c, PieceType pt) const { + return byColorBB[c] & byTypeBB[pt]; } -inline Bitboard Position::pieces(PieceType pt, Color c) const { - return byTypeBB[pt] & byColorBB[c]; +inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const { + return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]); } -inline Bitboard Position::pieces(PieceType pt1, PieceType pt2) const { - return byTypeBB[pt1] | byTypeBB[pt2]; +template inline int Position::count(Color c) const { + return pieceCount[make_piece(c, Pt)]; } -inline Bitboard Position::pieces(PieceType pt1, PieceType pt2, Color c) const { - return (byTypeBB[pt1] | byTypeBB[pt2]) & byColorBB[c]; +template inline int Position::count() const { + return pieceCount[make_piece(WHITE, Pt)] + pieceCount[make_piece(BLACK, Pt)]; } -inline int Position::piece_count(Color c, PieceType pt) const { - return pieceCount[c][pt]; +template inline const Square* Position::squares(Color c) const { + return pieceList[make_piece(c, Pt)]; } -inline const Square* Position::piece_list(Color c, PieceType pt) const { - return pieceList[c][pt]; +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 Square Position::king_square(Color c) const { - return pieceList[c][KING][0]; +inline bool Position::is_on_semiopen_file(Color c, Square s) const { + return !(pieces(c, PAWN) & file_bb(s)); } -inline bool Position::can_castle(CastleRight f) const { - return st->castleRights & f; +inline bool Position::can_castle(CastlingRight cr) const { + return st->castlingRights & cr; } -inline bool Position::can_castle(Color c) const { - return st->castleRights & ((WHITE_OO | WHITE_OOO) << c); +inline int Position::castling_rights(Color c) const { + return st->castlingRights & (c == WHITE ? WHITE_CASTLING : BLACK_CASTLING); } -inline Square Position::castle_rook_square(CastleRight f) const { - return castleRookSquare[f]; +inline bool Position::castling_impeded(CastlingRight cr) const { + return byTypeBB[ALL_PIECES] & castlingPath[cr]; } -template<> -inline Bitboard Position::attacks_from(Square s, Color c) const { - return StepAttacksBB[make_piece(c, PAWN)][s]; +inline Square Position::castling_rook_square(CastlingRight cr) const { + return castlingRookSquare[cr]; } -template // Knight and King and white pawns +template inline Bitboard Position::attacks_from(Square s) const { - return StepAttacksBB[Piece][s]; + assert(Pt != PAWN); + return Pt == BISHOP || Pt == ROOK ? attacks_bb(s, byTypeBB[ALL_PIECES]) + : Pt == QUEEN ? attacks_from(s) | attacks_from(s) + : PseudoAttacks[Pt][s]; } template<> -inline Bitboard Position::attacks_from(Square s) const { - return bishop_attacks_bb(s, occupied_squares()); +inline Bitboard Position::attacks_from(Square s, Color c) const { + return PawnAttacks[c][s]; } -template<> -inline Bitboard Position::attacks_from(Square s) const { - return rook_attacks_bb(s, occupied_squares()); +inline Bitboard Position::attacks_from(PieceType pt, Square s) const { + return attacks_bb(pt, s, byTypeBB[ALL_PIECES]); } -template<> -inline Bitboard Position::attacks_from(Square s) const { - return attacks_from(s) | attacks_from(s); +inline Bitboard Position::attackers_to(Square s) const { + return attackers_to(s, byTypeBB[ALL_PIECES]); } inline Bitboard Position::checkers() const { return st->checkersBB; } -inline bool Position::in_check() const { - return st->checkersBB != 0; +inline Bitboard Position::blockers_for_king(Color c) const { + return st->blockersForKing[c]; } -inline bool Position::pawn_is_passed(Color c, Square s) const { - return !(pieces(PAWN, flip(c)) & passed_pawn_mask(c, s)); +inline Bitboard Position::check_squares(PieceType pt) const { + return st->checkSquares[pt]; } -inline Key Position::get_key() const { - return st->key; +inline bool Position::is_discovery_check_on_king(Color c, Move m) const { + return st->blockersForKing[c] & from_sq(m); } -inline Key Position::get_exclusion_key() const { - return st->key ^ zobExclusion; +inline bool Position::pawn_passed(Color c, Square s) const { + return !(pieces(~c, PAWN) & passed_pawn_span(c, s)); } -inline Key Position::get_pawn_key() const { - return st->pawnKey; +inline bool Position::advanced_pawn_push(Move m) const { + return type_of(moved_piece(m)) == PAWN + && relative_rank(sideToMove, to_sq(m)) > RANK_5; } -inline Key Position::get_material_key() const { - return st->materialKey; +inline int Position::pawns_on_same_color_squares(Color c, Square s) const { + return popcount(pieces(c, PAWN) & ((DarkSquares & s) ? DarkSquares : ~DarkSquares)); } -inline Score Position::pst(Piece p, Square s) const { - return pieceSquareTable[p][s]; +inline Key Position::key() const { + return st->key; } -inline Score Position::pst_delta(Piece piece, Square from, Square to) const { - return pieceSquareTable[piece][to] - pieceSquareTable[piece][from]; +inline Key Position::pawn_key() const { + return st->pawnKey; } -inline Score Position::value() const { - return st->value; +inline Key Position::material_key() const { + return st->materialKey; } -inline Value Position::non_pawn_material(Color c) const { - return st->npMaterial[c]; +inline Score Position::psq_score() const { + return psq; } -inline bool Position::is_passed_pawn_push(Move m) const { - - return board[move_from(m)] == make_piece(sideToMove, PAWN) - && pawn_is_passed(sideToMove, move_to(m)); +inline Value Position::non_pawn_material(Color c) const { + return st->nonPawnMaterial[c]; } -inline int Position::startpos_ply_counter() const { - return startPosPly + st->pliesFromNull; // HACK +inline Value Position::non_pawn_material() const { + return st->nonPawnMaterial[WHITE] + st->nonPawnMaterial[BLACK]; } -inline bool Position::opposite_colored_bishops() const { +inline int Position::game_ply() const { + return gamePly; +} - 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::has_pawn_on_7th(Color c) const { - return pieces(PAWN, c) & 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 { 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) != NORMAL ? type_of(m) != CASTLING : !empty(to_sq(m)); +} +inline bool Position::capture(Move m) const { assert(is_ok(m)); - return is_special(m) ? !is_castle(m) : !square_is_empty(move_to(m)); + // Castling is encoded as "king captures rook" + return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == ENPASSANT; } -inline bool Position::is_capture(Move m) const { +inline Piece Position::captured_piece() const { + return st->capturedPiece; +} - // Note that castle is coded as "king captures the rook" - assert(is_ok(m)); - return (!square_is_empty(move_to(m)) && !is_castle(m)) || is_enpassant(m); +inline Thread* Position::this_thread() const { + return thisThread; +} + +inline void Position::put_piece(Piece pc, Square s) { + + board[s] = pc; + byTypeBB[ALL_PIECES] |= s; + 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 PieceType Position::captured_piece_type() const { - return st->capturedType; +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 invariant to a do_move() + undo_move() sequence. + byTypeBB[ALL_PIECES] ^= s; + 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[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 = square_bb(from) | square_bb(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 int Position::thread() const { - return threadID; +inline void Position::do_move(Move m, StateInfo& newSt) { + do_move(m, newSt, gives_check(m)); } -#endif // !defined(POSITION_H_INCLUDED) +#endif // #ifndef POSITION_H_INCLUDED