function format($size)
{
$sizetext = array(" B", " KB", " MB", " GB", " TB", " PB", " EB", " ZB", " YB");
return round($size/pow(1024,($i=floor(log($size,1024)))),2).$sizetext[$i];
}

public string formatSize(long size)
{
if (size == 0) return "0";
string[] sizetext = new string[] { " B", " KB", " MB", " GB", " TB", " PB" };
int i = (int)Math.Floor(Math.Log(size, 1024));
return Math.Round(size / Math.Pow(1024, i), 2).ToString() + sizetext[i];
}