getbytes.php

function bytes($a) {
    $unim = array("B","KB","MB","GB","TB","PB");
    $c = 0;
    while ($a>=1024) {
        $c++;
        $a = $a/1024;
    }
    return number_format($a,($c ? 2 : 0),",",".")." ".$unim[$c];
}