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108 lines
3.2 KiB
C++
108 lines
3.2 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#if !defined(PAWNS_H_INCLUDED)
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#define PAWNS_H_INCLUDED
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#include "position.h"
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#include "tt.h"
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#include "types.h"
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const int PawnTableSize = 16384;
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/// PawnInfo is a class which contains various information about a pawn
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/// structure. Currently, it only includes a middle game and an end game
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/// pawn structure evaluation, and a bitboard of passed pawns. We may want
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/// to add further information in the future. A lookup to the pawn hash
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/// table (performed by calling the pawn_info method in a PawnInfoTable
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/// object) returns a pointer to a PawnInfo object.
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class PawnInfo {
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friend class PawnInfoTable;
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public:
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Score pawns_value() const;
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Bitboard pawn_attacks(Color c) const;
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Bitboard passed_pawns(Color c) const;
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int file_is_half_open(Color c, File f) const;
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int has_open_file_to_left(Color c, File f) const;
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int has_open_file_to_right(Color c, File f) const;
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template<Color Us>
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Score king_shelter(const Position& pos, Square ksq);
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private:
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template<Color Us>
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Score updateShelter(const Position& pos, Square ksq);
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Key key;
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Bitboard passedPawns[2];
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Bitboard pawnAttacks[2];
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Square kingSquares[2];
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Score value;
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int halfOpenFiles[2];
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Score kingShelters[2];
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};
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/// The PawnInfoTable class represents a pawn hash table. The most important
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/// method is pawn_info, which returns a pointer to a PawnInfo object.
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class PawnInfoTable : public SimpleHash<PawnInfo, PawnTableSize> {
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public:
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PawnInfo* pawn_info(const Position& pos) const;
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private:
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template<Color Us>
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static Score evaluate_pawns(const Position& pos, Bitboard ourPawns, Bitboard theirPawns, PawnInfo* pi);
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};
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inline Score PawnInfo::pawns_value() const {
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return value;
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}
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inline Bitboard PawnInfo::pawn_attacks(Color c) const {
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return pawnAttacks[c];
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}
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inline Bitboard PawnInfo::passed_pawns(Color c) const {
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return passedPawns[c];
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}
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inline int PawnInfo::file_is_half_open(Color c, File f) const {
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return halfOpenFiles[c] & (1 << int(f));
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}
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inline int PawnInfo::has_open_file_to_left(Color c, File f) const {
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return halfOpenFiles[c] & ((1 << int(f)) - 1);
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}
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inline int PawnInfo::has_open_file_to_right(Color c, File f) const {
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return halfOpenFiles[c] & ~((1 << int(f+1)) - 1);
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}
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template<Color Us>
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inline Score PawnInfo::king_shelter(const Position& pos, Square ksq) {
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return kingSquares[Us] == ksq ? kingShelters[Us] : updateShelter<Us>(pos, ksq);
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}
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#endif // !defined(PAWNS_H_INCLUDED)
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