Singelton for stateless classes with more constness.

sundeepdwd · Apr 6, 2016 · 4b9fde2 · 4b9fde2
1 parent 78c853a
commit 4b9fde2
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/festus/value-weight-singleton.h b/festus/value-weight-singleton.h
@@ -43,6 +43,15 @@ struct DefaultInstance {
 template <class S>
 const S *const DefaultInstance<S>::kInstance = new S();
 
+template <class S>
+struct DefaultStaticInstance {
+ static constexpr S kStaticInstance = {};
+ static constexpr const S &Instance() { return kStaticInstance; }
+};
+
+template <class S>
+constexpr S DefaultStaticInstance<S>::kStaticInstance;
+
 // OpenFst weight façade for semirings whose elements are passed by value.
 //
 // This version works with a semiring class S with const member functions and