Text Processing in Ada 95

[Rob Norris <firstname.lastname@baesystems.com>]

Suppose I have a text file such as:

tom
dick
harry

Then I want to insert the line "dave" after tom so the file is

tom
dave
dick
harry

Also suppose text file can get rather large.

Currently I'm using text_io which means I have to copy the whole thing into memory, insert the line
then over write the file with new contents. direct_io is not an option (varing string lengths)

What alternatives should I consider for making insertions faster?
(NB retrieval of a line needs to be fairly quick as well).

Thanks in advance.