public static function getFileSize($pathToFile, $unit = 'B')
{
$unit = strtoupper($unit);
$units = array('TB' => pow(1024, 4), 'GB' => pow(1024, 3), 'MB' => pow(1024, 2), 'KB' => 1024, 'B' => 1);
if (!array_key_exists($unit, $units)) {
throw new Exception('Invalid unit given');
}
if (!file_exists($pathToFile)) {
return;
}
$filesize = filesize($pathToFile);
$factor = $units[$unit];
$converted = $filesize / $factor;
return $converted;
}