Fix a coverity scan warning

[stockfish] / src / endgame.h

diff --git a/src/endgame.h b/src/endgame.h
index 20e4a1d8e17ba7f84fdbd5cbefc1344e1e606805..453d8b29d47d98780fb8a04bb00da8efed95ff8c 100644 (file)
--- a/src/endgame.h
+++ b/src/endgame.h
@@ -21,7 +21,10 @@
 #define ENDGAME_H_INCLUDED
 
 #include <map>
+#include <memory>
 #include <string>
+#include <type_traits>
+#include <utility>
 
 #include "position.h"
 #include "types.h"
@@ -45,7 +48,7 @@ enum EndgameType {
 
 
   // Scaling functions
-  SCALE_FUNS,
+  SCALING_FUNCTIONS,
 
   KBPsK,   // KB and pawns vs K
   KQKRPs,  // KQ vs KR and pawns
@@ -63,11 +66,9 @@ enum EndgameType {
 
 
 /// Endgame functions can be of two types depending on whether they return a
-/// Value or a ScaleFactor. Type eg_fun<int>::type returns either ScaleFactor
-/// or Value depending on whether the template parameter is 0 or 1.
-
-template<int> struct eg_fun { typedef Value type; };
-template<> struct eg_fun<1> { typedef ScaleFactor type; };
+/// Value or a ScaleFactor.
+template<EndgameType E>
+using eg_fun = std::conditional<(E < SCALING_FUNCTIONS), Value, ScaleFactor>;
 
 
 /// Base and derived templates for endgame evaluation and scaling functions
@@ -81,7 +82,7 @@ struct EndgameBase {
 };
 
 
-template<EndgameType E, typename T = typename eg_fun<(E > SCALE_FUNS)>::type>
+template<EndgameType E, typename T = typename eg_fun<E>::type>
 struct Endgame : public EndgameBase<T> {
 
   explicit Endgame(Color c) : strongSide(c), weakSide(~c) {}
@@ -94,28 +95,26 @@ private:
 
 
 /// The Endgames class stores the pointers to endgame evaluation and scaling
-/// base objects in two std::map typedefs. We then use polymorphism to invoke
-/// the actual endgame function by calling its virtual operator().
+/// base objects in two std::map. We use polymorphism to invoke the actual
+/// endgame function by calling its virtual operator().
 
 class Endgames {
 
-  typedef std::map<Key, EndgameBase<eg_fun<0>::type>*> M1;
-  typedef std::map<Key, EndgameBase<eg_fun<1>::type>*> M2;
+  template<typename T> using Map = std::map<Key, std::unique_ptr<T>>;
 
-  M1 m1;
-  M2 m2;
+  template<EndgameType E, typename T = EndgameBase<typename eg_fun<E>::type>>
+  void add(const std::string& code);
 
-  M1& map(M1::mapped_type) { return m1; }
-  M2& map(M2::mapped_type) { return m2; }
+  template<typename T, int I = std::is_same<T, EndgameBase<ScaleFactor>>::value>
+  Map<T>& map() { return std::get<I>(maps); }
 
-  template<EndgameType E> void add(const std::string& code);
+  std::pair<Map<EndgameBase<Value>>, Map<EndgameBase<ScaleFactor>>> maps;
 
 public:
   Endgames();
- ~Endgames();
 
-  template<typename T> T probe(Key key, T& eg)
-  { return eg = map(eg).count(key) ? map(eg)[key] : NULL; }
+  template<typename T, typename E = EndgameBase<T>> E* probe(Key key)
+  { return map<E>().count(key) ? map<E>()[key].get() : nullptr; }
 };
 
 #endif // #ifndef ENDGAME_H_INCLUDED