My algorithm already checks that! Sure, for Perl it looks like all the strings are 8 characters, but the check is done by a C routine, who thinks that strings ends before the first \0 character.

It could be a bit optimized to take advantage of this, but all it does is save a few years of running time, at the expense of uglier, and harder to maintain, code. More code as well, and we all know that programmer time is more expensive than CPU time.