2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
5 Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
7 Stockfish is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 Stockfish is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #ifndef ENDGAME_H_INCLUDED
22 #define ENDGAME_H_INCLUDED
26 #include <type_traits>
27 #include <unordered_map>
34 /// EndgameCode lists all supported endgame functions by corresponding codes
41 KXK, // Generic "mate lone king" eval
51 KBPsK, // KB and pawns vs K
52 KQKRPs, // KQ vs KR and pawns
55 KRPPKRP, // KRPP vs KRP
56 KPsK, // K and pawns vs K
66 /// Endgame functions can be of two types depending on whether they return a
67 /// Value or a ScaleFactor.
69 template<EndgameCode E> using
70 eg_type = typename std::conditional<(E < SCALING_FUNCTIONS), Value, ScaleFactor>::type;
73 /// Base and derived functors for endgame evaluation and scaling functions
78 explicit EndgameBase(Color c) : strongSide(c), weakSide(~c) {}
79 virtual ~EndgameBase() = default;
80 virtual T operator()(const Position&) const = 0;
82 const Color strongSide, weakSide;
86 template<EndgameCode E, typename T = eg_type<E>>
87 struct Endgame : public EndgameBase<T> {
89 explicit Endgame(Color c) : EndgameBase<T>(c) {}
90 T operator()(const Position&) const override;
94 /// The Endgames namespace handles the pointers to endgame evaluation and scaling
95 /// base objects in two std::map. We use polymorphism to invoke the actual
96 /// endgame function by calling its virtual operator().
100 template<typename T> using Ptr = std::unique_ptr<EndgameBase<T>>;
101 template<typename T> using Map = std::unordered_map<Key, Ptr<T>>;
103 extern std::pair<Map<Value>, Map<ScaleFactor>> maps;
109 return std::get<std::is_same<T, ScaleFactor>::value>(maps);
112 template<EndgameCode E, typename T = eg_type<E>>
113 void add(const std::string& code) {
116 map<T>()[Position().set(code, WHITE, &st).material_key()] = Ptr<T>(new Endgame<E>(WHITE));
117 map<T>()[Position().set(code, BLACK, &st).material_key()] = Ptr<T>(new Endgame<E>(BLACK));
121 const EndgameBase<T>* probe(Key key) {
122 auto it = map<T>().find(key);
123 return it != map<T>().end() ? it->second.get() : nullptr;
127 #endif // #ifndef ENDGAME_H_INCLUDED