CBackup::getNextName

static function getNextName($file)
{
	static $CACHE;
	$c = &$CACHE[$file];

	if (!$c)
	{
		$l = strrpos($file, '.');
		$num = substr($file,$l+1);
		if (is_numeric($num))
			$file = substr($file,0,$l+1).++$num;
		else
			$file .= '.1';
		$c = $file;
	}
	return $c;
}