X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.h;h=8342df3c1efa067dea1f688fdb42d719d33c68f6;hp=c25244a6504cc27033554117ee029460a3581b7b;hb=fa1e3427bdf7f6347326015a381014564e8fb337;hpb=a6e0f62a4f83bf4303e920d5f689de7cbc0467e8 diff --git a/src/position.h b/src/position.h index c25244a6..8342df3c 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) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2017 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 @@ -17,90 +18,66 @@ along with this program. If not, see . */ -#if !defined(POSITION_H_INCLUDED) +#ifndef POSITION_H_INCLUDED #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 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 psq; + + // 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 (will be recomputed anyhow) + Key key; + Bitboard checkersBB; + Piece capturedPiece; StateInfo* previous; + Bitboard blockersForKing[COLOR_NB]; + Bitboard pinnersForKing[COLOR_NB]; + Bitboard checkSquares[PIECE_TYPE_NB]; }; +// In a std::deque references to elements are unaffected upon 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 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 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& 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); + 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; @@ -110,145 +87,133 @@ 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 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 int count(Color c) const; + template int count() const; + template const Square* squares(Color c) const; + template 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; + 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; - 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 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; + 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_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& 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(); + void increment_nodes(); + void increment_tbHits(); - // Static exchange evaluation - int see(Move m, int asymmThreshold = 0) 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; + 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); - bool is_draw() const; + uint64_t nodes_searched() const; + uint64_t tb_hits() const; + bool is_draw(int ply) 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 put_piece(Piece p, Square s); - void set_castle_right(Color c, Square rfrom); - - // Helper functions - void do_castle(Square kfrom, Square kto, Square rfrom, Square rto); - 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 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 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; + uint64_t tbHits; 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]; } @@ -273,53 +238,58 @@ inline Bitboard Position::pieces(Color c, PieceType pt1, PieceType pt2) const { return byColorBB[c] & (byTypeBB[pt1] | byTypeBB[pt2]); } -inline int Position::piece_count(Color c, PieceType pt) const { - return pieceCount[c][pt]; +template inline int Position::count(Color c) const { + return pieceCount[make_piece(c, Pt)]; } -inline const Square* Position::piece_list(Color c, PieceType pt) 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)]; +} + +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::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 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_from(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 { @@ -331,23 +301,28 @@ inline Bitboard Position::checkers() const { } inline Bitboard Position::discovered_check_candidates() const { - return hidden_checkers(); + return st->blockersForKing[~sideToMove] & pieces(sideToMove); +} + +inline Bitboard Position::pinned_pieces(Color c) const { + return st->blockersForKing[c] & pieces(c); } -inline Bitboard Position::pinned_pieces() const { - return hidden_checkers(); +inline Bitboard Position::check_squares(PieceType pt) const { + return st->checkSquares[pt]; } -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 { @@ -363,59 +338,110 @@ inline Score Position::psq_score() const { } inline Value Position::non_pawn_material(Color c) const { - return st->npMaterial[c]; + return st->nonPawnMaterial[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)); +inline Value Position::non_pawn_material() const { + return st->nonPawnMaterial[WHITE] + st->nonPawnMaterial[BLACK]; } inline int Position::game_ply() const { return gamePly; } -inline bool Position::opposite_bishops() const { +inline int Position::rule50_count() const { + return st->rule50; +} - return pieceCount[WHITE][BISHOP] == 1 - && pieceCount[BLACK][BISHOP] == 1 - && opposite_colors(pieceList[WHITE][BISHOP][0], pieceList[BLACK][BISHOP][0]); +inline uint64_t Position::nodes_searched() const { + return nodes; } -inline bool Position::bishop_pair(Color c) const { +inline void Position::increment_nodes() { + nodes++; +} - return pieceCount[c][BISHOP] >= 2 - && opposite_colors(pieceList[c][BISHOP][0], pieceList[c][BISHOP][1]); +inline uint64_t Position::tb_hits() const { + return tbHits; } -inline bool Position::pawn_on_7th(Color c) const { - return pieces(c, PAWN) & rank_bb(relative_rank(c, RANK_7)); +inline void Position::increment_tbHits() { + tbHits++; +} + +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) ? 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 { - - // Note that castle is coded as "king captures the rook" +inline bool Position::capture(Move m) const { assert(is_ok(m)); - return (!is_empty(to_sq(m)) && type_of(m) != CASTLE) || type_of(m) == ENPASSANT; + // 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; } -#endif // !defined(POSITION_H_INCLUDED) +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)]++; +} + +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)]--; +} + +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 from_to_bb = SquareBB[from] ^ SquareBB[to]; + byTypeBB[ALL_PIECES] ^= from_to_bb; + byTypeBB[type_of(pc)] ^= from_to_bb; + byColorBB[color_of(pc)] ^= from_to_bb; + board[from] = NO_PIECE; + board[to] = pc; + index[to] = index[from]; + pieceList[pc][index[to]] = to; +} + +inline void Position::do_move(Move m, StateInfo& newSt) { + do_move(m, newSt, gives_check(m)); +} + +#endif // #ifndef POSITION_H_INCLUDED