/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
+
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-
+
You should have received a copy of the GNU General Public License
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
-////
-//// Includes
-////
+#include <map>
+#include <memory>
+#include <string>
+#include <type_traits>
+#include <utility>
#include "position.h"
-#include "scale.h"
-#include "value.h"
-
+#include "types.h"
-////
-//// Types
-////
-/// Abstract base class for all special endgame evaluation functions:
+/// EndgameCode lists all supported endgame functions by corresponding codes
-class EndgameEvaluationFunction {
-public:
- EndgameEvaluationFunction(Color c);
- virtual ~EndgameEvaluationFunction() { }
+enum EndgameCode {
- virtual Value apply(const Position &pos) =0;
+ EVALUATION_FUNCTIONS,
+ KNNK, // KNN vs K
+ 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
-protected:
- Color strongerSide, weakerSide;
+ 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, // K and pawns vs K
+ KBPKB, // KBP vs KB
+ KBPPKB, // KBPP vs KB
+ KBPKN, // KBP vs KN
+ KNPK, // KNP vs K
+ KNPKB, // KNP vs KB
+ KPKP // KP vs KP
};
-/// Subclasses for various concrete endgames:
+/// Endgame functions can be of two types depending on whether they return a
+/// Value or a ScaleFactor.
+template<EndgameCode E> using
+eg_type = typename std::conditional<(E < SCALING_FUNCTIONS), Value, ScaleFactor>::type;
-// Generic "mate lone king" eval:
-class KXKEvaluationFunction : public EndgameEvaluationFunction {
-public:
- KXKEvaluationFunction(Color c);
- Value apply(const Position &pos);
-};
-// KBN vs K:
-class KBNKEvaluationFunction : public EndgameEvaluationFunction {
-public:
- KBNKEvaluationFunction(Color c);
- Value apply(const Position &pos);
-};
+/// Base and derived functors for endgame evaluation and scaling functions
-// KP vs K:
-class KPKEvaluationFunction : public EndgameEvaluationFunction {
-public:
- KPKEvaluationFunction(Color c);
- Value apply(const Position &pos);
-};
+template<typename T>
+struct EndgameBase {
-// KR vs KP:
-class KRKPEvaluationFunction : public EndgameEvaluationFunction {
-public:
- KRKPEvaluationFunction(Color c);
- Value apply(const Position &pos);
-};
+ explicit EndgameBase(Color c) : strongSide(c), weakSide(~c) {}
+ virtual ~EndgameBase() = default;
+ virtual T operator()(const Position&) const = 0;
-// KR vs KB:
-class KRKBEvaluationFunction : public EndgameEvaluationFunction {
-public:
- KRKBEvaluationFunction(Color c);
- Value apply(const Position &pos);
+ const Color strongSide, weakSide;
};
-// KR vs KN:
-class KRKNEvaluationFunction : public EndgameEvaluationFunction {
-public:
- KRKNEvaluationFunction(Color c);
- Value apply(const Position &pos);
-};
-// KQ vs KR:
-class KQKREvaluationFunction : public EndgameEvaluationFunction {
-public:
- KQKREvaluationFunction(Color c);
- Value apply(const Position &pos);
-};
-
-
-/// Abstract base class for all evaluation scaling functions:
+template<EndgameCode E, typename T = eg_type<E>>
+struct Endgame : public EndgameBase<T> {
-class ScalingFunction {
-public:
- ScalingFunction(Color c);
- virtual ~ScalingFunction() { }
-
- virtual ScaleFactor apply(const Position &pos) =0;
-
-protected:
- Color strongerSide, weakerSide;
+ explicit Endgame(Color c) : EndgameBase<T>(c) {}
+ T operator()(const Position&) const override;
};
-/// Subclasses for various concrete endgames:
+/// The Endgames class stores 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().
-// KBP vs K:
-class KBPKScalingFunction : public ScalingFunction {
-public:
- KBPKScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
-};
+class Endgames {
-// KQ vs KRP:
-class KQKRPScalingFunction: public ScalingFunction {
-public:
- KQKRPScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
-};
+ template<typename T> using Ptr = std::unique_ptr<EndgameBase<T>>;
+ template<typename T> using Map = std::map<Key, Ptr<T>>;
-// KRP vs KR:
-class KRPKRScalingFunction : public ScalingFunction {
-public:
- KRPKRScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
-};
-
-// KRPP vs KRP:
-class KRPPKRPScalingFunction : public ScalingFunction {
-public:
- KRPPKRPScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
-};
+ template<typename T>
+ Map<T>& map() {
+ return std::get<std::is_same<T, ScaleFactor>::value>(maps);
+ }
-// King and pawns vs king:
-class KPsKScalingFunction : public ScalingFunction {
-public:
- KPsKScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
-};
+ template<EndgameCode E, typename T = eg_type<E>, typename P = Ptr<T>>
+ void add(const std::string& code) {
-// KBP vs KB:
-class KBPKBScalingFunction : public ScalingFunction {
-public:
- KBPKBScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
-};
+ StateInfo st;
+ map<T>()[Position().set(code, WHITE, &st).material_key()] = P(new Endgame<E>(WHITE));
+ map<T>()[Position().set(code, BLACK, &st).material_key()] = P(new Endgame<E>(BLACK));
+ }
-// KBP vs KN:
-class KBPKNScalingFunction : public ScalingFunction {
-public:
- KBPKNScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
-};
+ std::pair<Map<Value>, Map<ScaleFactor>> maps;
-// KNP vs K:
-class KNPKScalingFunction : public ScalingFunction {
public:
- KNPKScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
-};
+ Endgames();
-// KP vs KP:
-class KPKPScalingFunction : public ScalingFunction {
-public:
- KPKPScalingFunction(Color c);
- ScaleFactor apply(const Position &pos);
+ template<typename T>
+ EndgameBase<T>* probe(Key key) {
+ return map<T>().count(key) ? map<T>()[key].get() : nullptr;
+ }
};
-
-////
-//// Constants and variables
-////
-
-// Generic "mate lone king" eval:
-extern KXKEvaluationFunction EvaluateKXK, EvaluateKKX;
-
-// KBN vs K:
-extern KBNKEvaluationFunction EvaluateKBNK, EvaluateKKBN;
-
-// KP vs K:
-extern KPKEvaluationFunction EvaluateKPK, EvaluateKKP;
-
-// KR vs KP:
-extern KRKPEvaluationFunction EvaluateKRKP, EvaluateKPKR;
-
-// KR vs KB:
-extern KRKBEvaluationFunction EvaluateKRKB, EvaluateKBKR;
-
-// KR vs KN:
-extern KRKNEvaluationFunction EvaluateKRKN, EvaluateKNKR;
-
-// KQ vs KR:
-extern KQKREvaluationFunction EvaluateKQKR, EvaluateKRKQ;
-
-// KBP vs K:
-extern KBPKScalingFunction ScaleKBPK, ScaleKKBP;
-
-// KQ vs KRP:
-extern KQKRPScalingFunction ScaleKQKRP, ScaleKRPKQ;
-
-// KRP vs KR:
-extern KRPKRScalingFunction ScaleKRPKR, ScaleKRKRP;
-
-// KRPP vs KRP:
-extern KRPPKRPScalingFunction ScaleKRPPKRP, ScaleKRPKRPP;
-
-// King and pawns vs king:
-extern KPsKScalingFunction ScaleKPsK, ScaleKKPs;
-
-// KBP vs KB:
-extern KBPKBScalingFunction ScaleKBPKB, ScaleKBKBP;
-
-// KBP vs KN:
-extern KBPKNScalingFunction ScaleKBPKN, ScaleKNKBP;
-
-// KNP vs K:
-extern KNPKScalingFunction ScaleKNPK, ScaleKKNP;
-
-// KP vs KP:
-extern KPKPScalingFunction ScaleKPKPw, ScaleKPKPb;
-
-
-////
-//// Prototypes
-////
-
-extern void init_bitbases();
-
-
-#endif // !defined(ENDGAME_H_INCLUDED)
+#endif // #ifndef ENDGAME_H_INCLUDED