Correggere `ereg is deprecated` in PHP 5.3

ereg('\.([^\.]*$)', $this->file_src_name, $extension);

preg_match('/\.([^\.]*$)/', $this->file_src_name, $extension);

$this->file_dst_name_body = ereg_replace('[^A-Za-z0-9_]', '', $this->file_dst_name_body);

$this->file_dst_name_body = preg_replace('/[^A-Za-z0-9_]/', '', $this->file_dst_name_body);