found advice suggesting casting strings to unsigned longs and incrementing and then casing back. Unfortunately these are arbitrary length strings and so I have no guarantee that this will be enough space

Sounds like a good opportunity to make use of perl's Math::BigInt module: 
use strict;
use warnings;
use Math::BigInt;

my $string = '12349' x 10;
my $x = Math::BigInt->new($string);
print  $x,  "\n"; # $x is a Math::BigInt object
$x++;
print "$x", "\n"; # "$x" is a string

__END__
Outputs:
12349123491234912349123491234912349123491234912349
12349123491234912349123491234912349123491234912350

[download]
Cheers,
Rob

In reply to Re: Add 1 to an arbitrary-length binary string by syphilis
in thread Add 1 to an arbitrary-length binary string by einhverfr

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