Or you could write that as:

use List::Util qw[ max ];

sub encoding {
    my @characters = ( 'A' .. 'Z', 'a' .. 'z', 0 .. 9, '-', '.' );
    my $max = max( $_[ 0 ] =~ /\d+/g );
    return join ',', map join( '', map $characters[ $_ / 64 ] . $chara
+cters[ $_ % 64 ], map $_ / $max * 4095, split /,/ ), split /\|/, $_[ 
+0 ];
    }
[download]

Udate: or another way to do it:

sub encoding {
    my ( $string ) = @_;
    my @characters = ( 'A' .. 'Z', 'a' .. 'z', 0 .. 9, '-', '.' );
    my $max = max( $string =~ /\d+/g );
    $string =~ s{ ( \d+ ) }{$characters[ ( $1 / $max * 4095 ) / 64 ]$c
+haracters[ ( $1 / $max * 4095 ) % 64 ]}xg;
    $string =~ tr/,//d;
    $string =~ tr/|/,/;
    return $string;
    }
[download]