internal repeats

[CSHL]

i'm looking for a C code which lists *all* internal repeats
in a sequence. no restriction on the repeating unit size,
the distance between the repeat units, or anything. this
list has to be complete.

is it a trivial task or a tricky one? i'm new to this topic, 
so i have no idea. any pointer is appreciated...( public
domain code, reference... or your own program-- i don't need
a complete code, only the subroutine dealing with this task
would be fine).

thanks in advance! -- w. li

wli at cshl.org