for::split

public function split()
{
	if($this->partChanged)
	{
		$this->addFooter();
	}

	$this->partList[] = $this->getName();
	$this->part++;

	$fileName = $this->partFile;
	$fileName = mb_substr($fileName, 0, -mb_strlen(self::FILE_EXT)).self::FILE_PART_SUFFIX.$this->part.mb_substr($fileName, -mb_strlen(self::FILE_EXT));

	$this->reInit($fileName);

	$this->partChanged = $this->isExists() && !$this->isSplitNeeded();

	return $fileName;
}