1 /*
2   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3   Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
4 
5   Stockfish is free software: you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation, either version 3 of the License, or
8   (at your option) any later version.
9 
10   Stockfish is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14 
15   You should have received a copy of the GNU General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.
17 */
18 
19 #ifndef PAWNS_H_INCLUDED
20 #define PAWNS_H_INCLUDED
21 
22 #include "misc.h"
23 #include "position.h"
24 #include "types.h"
25 
26 namespace Stockfish::Pawns {
27 
28 /// Pawns::Entry contains various information about a pawn structure. A lookup
29 /// to the pawn hash table (performed by calling the probe function) returns a
30 /// pointer to an Entry object.
31 
32 struct Entry {
33 
pawn_scoreEntry34   Score pawn_score(Color c) const { return scores[c]; }
pawn_attacksEntry35   Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
passed_pawnsEntry36   Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
pawn_attacks_spanEntry37   Bitboard pawn_attacks_span(Color c) const { return pawnAttacksSpan[c]; }
passed_countEntry38   int passed_count() const { return popcount(passedPawns[WHITE] | passedPawns[BLACK]); }
blocked_countEntry39   int blocked_count() const { return blockedCount; }
40 
41   template<Color Us>
king_safetyEntry42   Score king_safety(const Position& pos) {
43     return  kingSquares[Us] == pos.square<KING>(Us) && castlingRights[Us] == pos.castling_rights(Us)
44           ? kingSafety[Us] : (kingSafety[Us] = do_king_safety<Us>(pos));
45   }
46 
47   template<Color Us>
48   Score do_king_safety(const Position& pos);
49 
50   template<Color Us>
51   Score evaluate_shelter(const Position& pos, Square ksq) const;
52 
53   Key key;
54   Score scores[COLOR_NB];
55   Bitboard passedPawns[COLOR_NB];
56   Bitboard pawnAttacks[COLOR_NB];
57   Bitboard pawnAttacksSpan[COLOR_NB];
58   Square kingSquares[COLOR_NB];
59   Score kingSafety[COLOR_NB];
60   int castlingRights[COLOR_NB];
61   int blockedCount;
62 };
63 
64 typedef HashTable<Entry, 131072> Table;
65 
66 Entry* probe(const Position& pos);
67 
68 } // namespace Stockfish::Pawns
69 
70 #endif // #ifndef PAWNS_H_INCLUDED
71