Use polymorphism to resolve map() overloading

[stockfish] / src / endgame.h

diff --git a/src/endgame.h b/src/endgame.h
index 70f795cd19782c7a4aec23dd3c0217db51b4efd9..424a3591cb80e6a67b22c784f524621186d28a98 100644 (file)
--- a/src/endgame.h
+++ b/src/endgame.h
@@ -61,11 +61,12 @@ enum EndgameType {
 };
 
 
-/// Some magic to detect family type of endgame from its enum value
+/// Endgame functions can be of two types according if return a Value or a
+/// ScaleFactor. Type eg_fun<int>::type equals to either ScaleFactor or Value
+/// depending if the template parameter is 0 or 1.
 
-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<int> struct eg_fun { typedef Value type; };
+template<> struct eg_fun<1> { typedef ScaleFactor type; };
 
 
 /// Base and derived templates for endgame evaluation and scaling functions
@@ -79,7 +80,7 @@ struct EndgameBase {
 };
 
 
-template<EndgameType E, typename T = typename eg_family<E>::type>
+template<EndgameType E, typename T = typename eg_fun<(E > SCALE_FUNS)>::type>
 struct Endgame : public EndgameBase<T> {
 
   explicit Endgame(Color c) : strongerSide(c), weakerSide(~c) {}
@@ -97,14 +98,14 @@ private:
 
 class Endgames {
 
-  typedef std::map<Key, EndgameBase<Value>*> M1;
-  typedef std::map<Key, EndgameBase<ScaleFactor>*> M2;
+  typedef std::map<Key, EndgameBase<eg_fun<0>::type>*> M1;
+  typedef std::map<Key, EndgameBase<eg_fun<1>::type>*> M2;
 
   M1 m1;
   M2 m2;
 
-  M1& map(Value*) { return m1; }
-  M2& map(ScaleFactor*) { return m2; }
+  M1& map(M1::value_type::second_type) { return m1; }
+  M2& map(M2::value_type::second_type) { return m2; }
 
   template<EndgameType E> void add(const std::string& code);
 
@@ -112,8 +113,8 @@ public:
   Endgames();
   ~Endgames();
 
-  template<typename T> EndgameBase<T>* get(Key key) {
-    return map((T*)0).count(key) ? map((T*)0)[key] : NULL;
+  template<typename T> EndgameBase<T>* probe(Key key) {
+    return map((EndgameBase<T>*)0).count(key) ? map((EndgameBase<T>*)0)[key] : NULL;
   }
 };