Add string_view::empty()

opm/parser/eclipse/Utility/Stringview.hpp

@@ -56,6 +56,7 @@ namespace Opm {
 
             inline char operator[]( size_t ) const;
 
+            inline bool empty() const;
             inline size_t size() const;
             inline size_t length() const;
 
@@ -158,6 +159,10 @@ namespace Opm {
         return *(this->begin() + i);
     }
 
+    inline bool string_view::empty() const {
+        return std::distance( this->begin(), this->end() ) == 0;
+    }
+
     inline size_t string_view::size() const {
         return std::distance( this->begin(), this->end() );
     }