/*
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
#define POSITION_H_INCLUDED
#include <cassert>
-#include <cstddef>
+#include <deque>
+#include <memory> // For std::unique_ptr
+#include <string>
#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 castlingRights, 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)
+ 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<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 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& pos, Thread* t) { *this = pos; 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;
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<PieceType Pt> int count(Color c) const;
- template<PieceType Pt> const Square* list(Color c) const;
+ template<PieceType Pt> int count() const;
+ template<PieceType Pt> const Square* squares(Color c) const;
+ template<PieceType Pt> Square square(Color c) const;
+ bool is_on_semiopen_file(Color c, Square s) const;
// Castling
- int can_castle(Color c) const;
- int can_castle(CastlingRight cr) const;
- bool castling_impeded(CastlingRight cr) const;
- Square castling_rook_square(CastlingRight cr) const;
+ int castling_rights(Color c) const;
+ bool can_castle(CastlingRights cr) const;
+ bool castling_impeded(CastlingRights cr) const;
+ Square castling_rook_square(CastlingRights 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;
+ bool is_discovery_check_on_king(Color c, Move m) 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 pc, Square s) const;
+ Bitboard attackers_to(Square s, Bitboard occupied) const;
+ Bitboard attacks_from(PieceType pt, 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 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;
+ 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
- Value see(Move m) const;
- Value 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;
- uint64_t nodes_searched() const;
- void set_nodes_searched(uint64_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* step = NULL) const;
+ bool pos_is_ok() const;
void flip();
private:
// Initialization helpers (used while setting up a position)
- void clear();
void set_castling_right(Color c, Square rfrom);
void set_state(StateInfo* si) const;
+ void set_check_info(StateInfo* si) const;
- // Helper functions
- 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);
+ // 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<bool Do>
- void do_castling(Square from, Square& to, Square& rfrom, Square& rto);
+ void do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto);
- // 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 pieceCount[PIECE_NB];
+ Square pieceList[PIECE_NB][16];
int index[SQUARE_NB];
-
- // Other info
int castlingRightsMask[SQUARE_NB];
Square castlingRookSquare[CASTLING_RIGHT_NB];
Bitboard castlingPath[CASTLING_RIGHT_NB];
- StateInfo startState;
- uint64_t nodes;
int gamePly;
Color sideToMove;
+ Score psq;
Thread* thisThread;
StateInfo* st;
bool chess960;
};
-inline uint64_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(uint64_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[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];
}
}
template<PieceType Pt> inline int Position::count(Color c) const {
- return pieceCount[c][Pt];
+ return pieceCount[make_piece(c, Pt)];
+}
+
+template<PieceType Pt> inline int Position::count() const {
+ return pieceCount[make_piece(WHITE, Pt)] + pieceCount[make_piece(BLACK, Pt)];
}
-template<PieceType Pt> inline const Square* Position::list(Color c) const {
- return pieceList[c][Pt];
+template<PieceType Pt> inline const Square* Position::squares(Color c) const {
+ return pieceList[make_piece(c, Pt)];
+}
+
+template<PieceType Pt> 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 int Position::can_castle(CastlingRight cr) const {
+inline bool Position::can_castle(CastlingRights cr) const {
return st->castlingRights & cr;
}
-inline int Position::can_castle(Color c) const {
- return st->castlingRights & ((WHITE_OO | WHITE_OOO) << (2 * c));
+inline int Position::castling_rights(Color c) const {
+ return st->castlingRights & (c == WHITE ? WHITE_CASTLING : BLACK_CASTLING);
}
-inline bool Position::castling_impeded(CastlingRight cr) const {
+inline bool Position::castling_impeded(CastlingRights cr) const {
return byTypeBB[ALL_PIECES] & castlingPath[cr];
}
-inline Square Position::castling_rook_square(CastlingRight cr) const {
+inline Square Position::castling_rook_square(CastlingRights cr) const {
return castlingRookSquare[cr];
}
template<PieceType Pt>
inline Bitboard Position::attacks_from(Square s) const {
+ static_assert(Pt != PAWN, "Pawn attacks need color");
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];
+ : PseudoAttacks[Pt][s];
}
template<>
inline Bitboard Position::attacks_from<PAWN>(Square s, Color c) const {
- return StepAttacksBB[make_piece(c, PAWN)][s];
+ return PawnAttacks[c][s];
}
-inline Bitboard Position::attacks_from(Piece pc, Square s) const {
- return attacks_bb(pc, 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 {
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::check_squares(PieceType pt) const {
+ return st->checkSquares[pt];
}
-inline Bitboard Position::pinned_pieces(Color c) const {
- return check_blockers(c, c);
+inline bool Position::is_discovery_check_on_king(Color c, Move m) const {
+ return st->blockersForKing[c] & from_sq(m);
}
inline bool Position::pawn_passed(Color c, Square s) const {
- return !(pieces(~c, PAWN) & passed_pawn_mask(c, s));
+ return !(pieces(~c, PAWN) & passed_pawn_span(c, s));
}
inline bool Position::advanced_pawn_push(Move m) const {
return type_of(moved_piece(m)) == PAWN
- && relative_rank(sideToMove, from_sq(m)) > RANK_4;
+ && relative_rank(sideToMove, to_sq(m)) > RANK_5;
+}
+
+inline int Position::pawns_on_same_color_squares(Color c, Square s) const {
+ return popcount(pieces(c, PAWN) & ((DarkSquares & s) ? DarkSquares : ~DarkSquares));
}
inline Key Position::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<BISHOP>(WHITE), square<BISHOP>(BLACK));
}
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;
- 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
- 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 = from | 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
projects / stockfish / blobdiff