private void checkStruct(AbstractStruct struct) {
   List<StructEntry> flatList = struct.getFlatList();
   for (int i = 0; i < flatList.size(); i++) {
     if (flatList.get(i) instanceof StringRef) {
       StringRef ref = (StringRef) flatList.get(i);
       if (ref.getValue() >= 0 && ref.getValue() < strUsed.length) strUsed[ref.getValue()] = true;
     }
   }
 }