Edit: Ooops, my code only works for unsigned integers. I'll leave it here anyway, might at least come in handy for someone else at a later time... Ok, Here's a simple example of how i did it as a test:

#!/usr/bin/perl

use strict;
use warnings;

my $val = 70000;
print "Saving Value: $val\n";

# ENCODE
my @bytes;
for(my $i = 0; $i < 3; $i++) {
    $bytes[$i] = $val % 256;
    if($val) {
        $val = int($val / 256);
    }
}

my $savebytes = pack("ccc", @bytes);

# DECODE
my @newbytes = unpack("ccc", $savebytes);
my $newval = 0;

while(scalar @newbytes) {
    my $byte = pop @newbytes;
    $newval = $newval * 256;
    $newval += $byte;
}

print "Retrieved Value is: $newval\n";
[download]

Here's the output:

Saving Value: 70000
Retrieved Value is: 70000
[download]

I'm pretty sure there is a better way, but i'm not an expert on all this math stuff... Edit: If you have a lot of numbers to encode/decode, you might want to consider putting that stuff into a C module or use Inline::C for speed.