Add emplace_back, move_assignment to BoundedVector

Signed-off-by: Christopher Ho <christopherj.ho@gmail.com>

rosidl_generator_cpp/include/rosidl_generator_cpp/bounded_vector.hpp

@@ -207,8 +207,14 @@ class BoundedVector
   BoundedVector &
   operator=(const BoundedVector & __x)
   {
-    reinterpret_cast<std::vector<_Tp, _Alloc> *>(this)->operator=(
-      *reinterpret_cast<const std::vector<_Tp, _Alloc> *>(&__x));
+    (void)_Base::operator=(__x);
+    return *this;
+  }
+  /// %BoundedVector move assignment operator
+  BoundedVector &
+  operator=(BoundedVector && __x)
+  {
+    (void)_Base::operator=(std::forward<_Base &&>(__x));
     return *this;
   }
 
@@ -454,6 +460,16 @@ class BoundedVector
     _Base::push_back(__x);
   }
 
+  template<typename ... Args>
+  void
+  emplace_back(Args && ... args)
+  {
+    if (size() >= _UpperBound) {
+      throw std::length_error("Exceeded upper bound");
+    }
+    _Base::emplace_back(std::forward<Args>(args)...);
+  }
+
   /// Insert an object in %BoundedVector before specified iterator.
   /**
    * This function will insert an object of type T constructed with
@@ -607,6 +623,13 @@ class BoundedVector
   using _Base::erase;
   using _Base::pop_back;
   using _Base::clear;
+
+private:
+  /// Cast to base type, to make it easier to dispatch to base implementations
+  operator _Base&()
+  {
+    return *this;
+  }
 };
 
 /// Vector equality comparison.