This should be improved in a generic manner. What we can do is have new AttCache class inheriting from Att from which selected attribute can inherit (instead for Att). Which one to cache would be set in the libMEI configuration. These attribute would cache the original value which will be used when writing the attribute.

We need an additional virtual method Att::HasCacheValue() with would return false in Att but would be overwritten in AttCache. Then in methods writing attribute we would also check for the presence of a cached value.

@rettinghaus are you willing to implement this? Otherwise I would put it in the back burner list.

I'll have a look.

Great. I think it should be pretty straightforward.