Ref T219, added some utility functions in value classes

src/blackmisc/aviation/airporticaocode.cpp

@@ -21,6 +21,11 @@ namespace BlackMisc
             return this->m_icaoCode.compare(compareValue.getIcaoCode(), Qt::CaseInsensitive);
         }
 
+        bool CAirportIcaoCode::hasValidIcaoCode() const
+        {
+            return CAirportIcaoCode::isValidIcaoDesignator(this->getIcaoCode());
+        }
+
         bool CAirportIcaoCode::equalsString(const QString &icaoCode) const
         {
             CAirportIcaoCode other(icaoCode);

src/blackmisc/aviation/airporticaocode.h

@@ -41,6 +41,9 @@ namespace BlackMisc
             //! Is empty?
             bool isEmpty() const { return this->m_icaoCode.isEmpty(); }
 
+            //! Has valid code?
+            bool hasValidIcaoCode() const;
+
             //! Get code.
             const QString &asString() const { return this->m_icaoCode; }
 

src/blackmisc/aviation/atcstation.cpp

@@ -95,7 +95,7 @@ namespace BlackMisc
                               QLatin1String(" online: ") % boolToYesNo(m_isOnline) %
 
                               // controller
-                              (!m_controller.isValid() ? QStringLiteral("") :
+                              (m_controller.isNull() ? QStringLiteral("") :
                                QStringLiteral(" ") % m_controller.toQString(i18n)) %
 
                               // frequency