10_to_64.pl

#!/usr/bin/perl
use strict;
use warnings;
use Test::More;

BEGIN {
    my @table = (0 .. 9, 'A' .. 'Z', 'a' .. 'z', '_', '-');

    use constant NUM64 => \@table;
    use constant DIGIT => 6;
    use constant MASK  => (2**DIGIT - 1);
}

use Data::Dumper;
sub print_r {
    local $Data::Dumper::Sortkeys = 1;
    print Dumper @_;
}

print_r(NUM64) if 0;

sub conv10to64 {
    my $d = shift;

    my $result;

    while ($d) {
        $result = NUM64->[$d & MASK] . $result;
        $d >>= DIGIT;
    }

    return $result;
}

is(conv10to64(66), '12');

done_testing;