File size calculator

File size calculator function return file size format into kb, mb or gb.

function file_size($size, $out = 'kb', $precision = 2)
{
    switch ($out) {
        case 'kb':
            return round($size / 1024, $precision);
            break;
        case 'mb':
            return round($size / (1024 * 1024), $precision);
            break;
        case 'gb':
            return round($size / (1024 * 1024 * 1024), $precision);
            break;
    }
    return false;
}