/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2004-2022 The Stockfish developers (see AUTHORS file)
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-#if !defined(ENDGAME_H_INCLUDED)
+#ifndef ENDGAME_H_INCLUDED
#define ENDGAME_H_INCLUDED
+#include <memory>
#include <string>
-#include <map>
+#include <type_traits>
+#include <unordered_map>
+#include <utility>
#include "position.h"
#include "types.h"
+namespace Stockfish {
-/// EndgameType lists all supported endgames
+/// EndgameCode lists all supported endgame functions by corresponding codes
-enum EndgameType {
-
- // Evaluation functions
+enum EndgameCode {
+ EVALUATION_FUNCTIONS,
+ KNNK, // KNN vs K
+ KNNKP, // KNN vs KP
KXK, // Generic "mate lone king" eval
KBNK, // KBN vs K
KPK, // KP vs K
KRKP, // KR vs KP
KRKB, // KR vs KB
KRKN, // KR vs KN
+ KQKP, // KQ vs KP
KQKR, // KQ vs KR
- KBBKN, // KBB vs KN
- KNNK, // KNN vs K
- KmmKm, // K and two minors vs K and one or two minors
-
- // Scaling functions
- SCALE_FUNS,
-
- KBPsK, // KB+pawns vs K
- KQKRPs, // KQ vs KR+pawns
+ SCALING_FUNCTIONS,
+ KBPsK, // KB and pawns vs K
+ KQKRPs, // KQ vs KR and pawns
KRPKR, // KRP vs KR
+ KRPKB, // KRP vs KB
KRPPKRP, // KRPP vs KRP
- KPsK, // King and pawns vs king
+ KPsK, // K and pawns vs K
KBPKB, // KBP vs KB
KBPPKB, // KBPP vs KB
KBPKN, // KBP vs KN
- KNPK, // KNP vs K
KPKP // KP vs KP
};
-/// Some magic to detect family type of endgame from its enum value
+/// Endgame functions can be of two types depending on whether they return a
+/// Value or a ScaleFactor.
-template<bool> struct bool_to_type { typedef Value type; };
-template<> struct bool_to_type<true> { typedef ScaleFactor type; };
-template<EndgameType E> struct eg_family : public bool_to_type<(E > SCALE_FUNS)> {};
+template<EndgameCode E> using
+eg_type = typename std::conditional<(E < SCALING_FUNCTIONS), Value, ScaleFactor>::type;
-/// Base and derived templates for endgame evaluation and scaling functions
+/// Base and derived functors for endgame evaluation and scaling functions
template<typename T>
struct EndgameBase {
- virtual ~EndgameBase() {}
- virtual Color color() const = 0;
- virtual T apply(const Position&) const = 0;
+ explicit EndgameBase(Color c) : strongSide(c), weakSide(~c) {}
+ virtual ~EndgameBase() = default;
+ virtual T operator()(const Position&) const = 0;
+
+ const Color strongSide, weakSide;
};
-template<EndgameType E, typename T = typename eg_family<E>::type>
+template<EndgameCode E, typename T = eg_type<E>>
struct Endgame : public EndgameBase<T> {
- explicit Endgame(Color c) : strongerSide(c), weakerSide(flip(c)) {}
- Color color() const { return strongerSide; }
- T apply(const Position&) const;
-
-private:
- Color strongerSide, weakerSide;
+ explicit Endgame(Color c) : EndgameBase<T>(c) {}
+ T operator()(const Position&) const override;
};
-/// Endgames class stores in two std::map the pointers to endgame evaluation
-/// and scaling base objects. Then we use polymorphism to invoke the actual
-/// endgame function calling its apply() method that is virtual.
+/// The Endgames namespace handles the pointers to endgame evaluation and scaling
+/// base objects in two std::map. We use polymorphism to invoke the actual
+/// endgame function by calling its virtual operator().
-struct Endgames {
+namespace Endgames {
- template<typename T>
- struct Map { typedef std::map<Key, EndgameBase<T>*> type; };
+ template<typename T> using Ptr = std::unique_ptr<EndgameBase<T>>;
+ template<typename T> using Map = std::unordered_map<Key, Ptr<T>>;
- typedef Map<Value>::type M1;
- typedef Map<ScaleFactor>::type M2;
+ extern std::pair<Map<Value>, Map<ScaleFactor>> maps;
- Endgames();
- ~Endgames();
+ void init();
template<typename T>
- EndgameBase<T>* get(Key key) const {
+ Map<T>& map() {
+ return std::get<std::is_same<T, ScaleFactor>::value>(maps);
+ }
+
+ template<EndgameCode E, typename T = eg_type<E>>
+ void add(const std::string& code) {
- typedef typename Map<T>::type M;
- typename M::const_iterator it = map<M>().find(key);
- return it != map<M>().end() ? it->second : NULL;
+ StateInfo st;
+ map<T>()[Position().set(code, WHITE, &st).material_key()] = Ptr<T>(new Endgame<E>(WHITE));
+ map<T>()[Position().set(code, BLACK, &st).material_key()] = Ptr<T>(new Endgame<E>(BLACK));
}
-private:
- template<EndgameType E> void add(const std::string& keyCode);
- template<typename M> const M& map() const;
+ template<typename T>
+ const EndgameBase<T>* probe(Key key) {
+ auto it = map<T>().find(key);
+ return it != map<T>().end() ? it->second.get() : nullptr;
+ }
+}
- M1 m1;
- M2 m2;
-};
+} // namespace Stockfish
-#endif // !defined(ENDGAME_H_INCLUDED)
+#endif // #ifndef ENDGAME_H_INCLUDED