protected function extensionOfName($fileName)
    {
        if (mb_strpos($fileName, '.') === false) {
            return mb_strtolower($fileName);
        }

        return mb_strtolower(pathinfo($fileName, PATHINFO_EXTENSION));
    }
protected function extensionOfName($fileName)
    {
        if (mb_strpos($fileName, '.') === false) {
            return mb_strtolower($fileName);
        }

        return mb_strtolower(pathinfo($fileName, PATHINFO_EXTENSION));
    }
protected function extensionOfName ( $ fileName ) { if ( mb_strpos ( $ fileName , '.' ) === false ) { return mb_strtolower ( $ fileName ) ; } return mb_strtolower ( pathinfo ( $ fileName , PATHINFO_EXTENSION ) ) ; }
Calculate the extension of fileName.

@param string $fileName

@return string
Calculate the extension of fileName .