127 lines
3.4 KiB
C++
127 lines
3.4 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
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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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#ifndef ENDGAME_H_INCLUDED
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#define ENDGAME_H_INCLUDED
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#include <memory>
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#include <string>
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#include <type_traits>
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#include <unordered_map>
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#include <utility>
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#include "position.h"
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#include "types.h"
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namespace Stockfish {
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/// EndgameCode lists all supported endgame functions by corresponding codes
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enum EndgameCode {
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EVALUATION_FUNCTIONS,
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KNNK, // KNN vs K
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KNNKP, // KNN vs KP
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KXK, // Generic "mate lone king" eval
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KBNK, // KBN vs K
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KPK, // KP vs K
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KRKP, // KR vs KP
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KRKB, // KR vs KB
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KRKN, // KR vs KN
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KQKP, // KQ vs KP
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KQKR, // KQ vs KR
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SCALING_FUNCTIONS,
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KBPsK, // KB and pawns vs K
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KQKRPs, // KQ vs KR and pawns
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KRPKR, // KRP vs KR
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KRPKB, // KRP vs KB
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KRPPKRP, // KRPP vs KRP
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KPsK, // K and pawns vs K
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KBPKB, // KBP vs KB
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KBPPKB, // KBPP vs KB
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KBPKN, // KBP vs KN
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KPKP // KP vs KP
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};
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/// Endgame functions can be of two types depending on whether they return a
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/// Value or a ScaleFactor.
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template<EndgameCode E> using
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eg_type = typename std::conditional<(E < SCALING_FUNCTIONS), Value, ScaleFactor>::type;
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/// Base and derived functors for endgame evaluation and scaling functions
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template<typename T>
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struct EndgameBase {
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explicit EndgameBase(Color c) : strongSide(c), weakSide(~c) {}
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virtual ~EndgameBase() = default;
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virtual T operator()(const Position&) const = 0;
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const Color strongSide, weakSide;
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};
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template<EndgameCode E, typename T = eg_type<E>>
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struct Endgame : public EndgameBase<T> {
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explicit Endgame(Color c) : EndgameBase<T>(c) {}
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T operator()(const Position&) const override;
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};
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/// The Endgames namespace handles the pointers to endgame evaluation and scaling
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/// base objects in two std::map. We use polymorphism to invoke the actual
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/// endgame function by calling its virtual operator().
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namespace Endgames {
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template<typename T> using Ptr = std::unique_ptr<EndgameBase<T>>;
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template<typename T> using Map = std::unordered_map<Key, Ptr<T>>;
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extern std::pair<Map<Value>, Map<ScaleFactor>> maps;
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void init();
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template<typename T>
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Map<T>& map() {
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return std::get<std::is_same<T, ScaleFactor>::value>(maps);
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}
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template<EndgameCode E, typename T = eg_type<E>>
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void add(const std::string& code) {
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StateInfo st;
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map<T>()[Position().set(code, WHITE, &st).material_key()] = Ptr<T>(new Endgame<E>(WHITE));
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map<T>()[Position().set(code, BLACK, &st).material_key()] = Ptr<T>(new Endgame<E>(BLACK));
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}
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template<typename T>
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const EndgameBase<T>* probe(Key key) {
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auto it = map<T>().find(key);
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return it != map<T>().end() ? it->second.get() : nullptr;
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}
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}
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} // namespace Stockfish
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#endif // #ifndef ENDGAME_H_INCLUDED
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