public function guessDestinationFilename()
    {
        if (!empty($this->files_stack)) {
            $this->_cleanFilesStack();
            $this->init();

            $_fs = array();
            foreach ($this->files_stack as $_file) {
                $_fs[] = $_file->getFilename();
            }
            if (!empty($_fs)) {
                sort($_fs);
                $this->setDestinationFile(
                    md5(join('', $_fs))
                    .'_'.$this->__adapter_action
                    .'.'.$this->__adapter->file_extension
                );
                return $this->getDestinationFile();
            }
        }
        if (false===$this->silent) {
            throw new \RuntimeException(
                '[Compressor] Destination filename can\'t be guessed because files stack is empty!'
            );
        }
        return null;
    }