Indulge a bit on the template wizardy

[stockfish] / src / endgame.h

diff --git a/src/endgame.h b/src/endgame.h
index e40b4050756fee4b2fb8489b1a599ae6004aba43..a9634738bee0232c5c03117d62a21688a1a465cf 100644 (file)
--- a/src/endgame.h
+++ b/src/endgame.h
@@ -32,6 +32,7 @@
 enum EndgameType {
 
   // Evaluation functions
+
   KXK,   // Generic "mate lone king" eval
   KBNK,  // KBN vs K
   KPK,   // KP vs K
@@ -43,7 +44,9 @@ enum EndgameType {
   KNNK,  // KNN vs K
   KmmKm, // K and two minors vs K and one or two minors
 
+
   // Scaling functions
+
   KBPsK,   // KB+pawns vs K
   KQKRPs,  // KQ vs KR+pawns
   KRPKR,   // KRP vs KR
@@ -57,28 +60,28 @@ enum EndgameType {
 };
 
 
-/// Base and derived template class for endgame evaluation and scaling functions
+/// Base and derived templates for endgame evaluation and scaling functions
 
 template<typename T>
 struct EndgameBase {
 
   typedef EndgameBase<T> Base;
 
-  EndgameBase(Color c) : strongerSide(c), weakerSide(opposite_color(c)) {}
   virtual ~EndgameBase() {}
+  virtual Color color() const = 0;
   virtual T apply(const Position&) const = 0;
-  Color color() const { return strongerSide; }
-
-protected:
-  Color strongerSide, weakerSide;
 };
 
 
 template<typename T, EndgameType>
 struct Endgame : public EndgameBase<T> {
 
-  explicit Endgame(Color c): EndgameBase<T>(c) {}
+  explicit Endgame(Color c) : strongerSide(c), weakerSide(opposite_color(c)) {}
+  Color color() const { return strongerSide; }
   T apply(const Position&) const;
+
+private:
+  Color strongerSide, weakerSide;
 };
 
 
@@ -86,24 +89,23 @@ struct Endgame : public EndgameBase<T> {
 /// and scaling base objects. Then we use polymorphism to invoke the actual
 /// endgame function calling its apply() method that is virtual.
 
-class Endgames {
+struct Endgames {
 
-  typedef std::map<Key, EndgameBase<Value>*> EFMap;
-  typedef std::map<Key, EndgameBase<ScaleFactor>*> SFMap;
+  template<typename T>
+  struct EMap { typedef std::map<Key, EndgameBase<T>*> type; };
 
-public:
   Endgames();
   ~Endgames();
-  template<class T> T* get(Key key) const;
+  template<typename T> EndgameBase<T>* get(Key key) const;
 
 private:
-  template<class T> void add(const std::string& keyCode);
+  template<typename T, EndgameType E> void add(const std::string& keyCode);
 
   // Here we store two maps, for evaluate and scaling functions...
-  std::pair<EFMap, SFMap> maps;
+  std::pair<EMap<Value>::type, EMap<ScaleFactor>::type> maps;
 
   // ...and here is the accessing template function
-  template<typename T> const std::map<Key, T*>& get() const;
+  template<typename T> const typename EMap<T>::type& map() const;
 };
 
 #endif // !defined(ENDGAME_H_INCLUDED)