I'd like to see it count crlfs up to .pos on demand, store that info, and keep track of subsequently read crlfs as needed.
Though, would mean creating an array and storing every crlf's absolute or relative .pos in the file. The only problem is this array's integrity when you start writing to the file, removing lines or simply writing over crlfs... it would mean having to completly rehash that array using any number of methods to calculate new values depending on how the file was altered... short of just re-reading the entire file again.
It would be difficult, indeed.
