protected function isExtensionAllowed($filename)
    {
        // retrieve the extension
        $pos = strrpos($filename, '.');
        $extension = '';
        if ($pos !== false) {
            $extension = strtolower(substr($filename, $pos + 1));
        }

        // if we have an extension, validate it agains the black and white lists
        if ($extension) {
            // not in whitelist?
            if (sizeof($this->allowedExtensions) > 0 && !in_array($extension, $this->allowedExtensions)) {
                return false;
            }

            // in blacklist ?
            if (sizeof($this->deniedExtensions) && in_array($extension, $this->deniedExtensions)) {
                return false;
            }
        } elseif (sizeof($this->allowedExtensions) > 0) {
            // no extension given, thus not in the whitelist!
            return false;
        }

        return true;
    }
protected function isExtensionAllowed($filename)
    {
        // retrieve the extension
        $pos = strrpos($filename, '.');
        $extension = '';
        if ($pos !== false) {
            $extension = strtolower(substr($filename, $pos + 1));
        }

        // if we have an extension, validate it agains the black and white lists
        if ($extension) {
            // not in whitelist?
            if (sizeof($this->allowedExtensions) > 0 && !in_array($extension, $this->allowedExtensions)) {
                return false;
            }

            // in blacklist ?
            if (sizeof($this->deniedExtensions) && in_array($extension, $this->deniedExtensions)) {
                return false;
            }
        } elseif (sizeof($this->allowedExtensions) > 0) {
            // no extension given, thus not in the whitelist!
            return false;
        }

        return true;
    }
protected function isExtensionAllowed ( $ filename ) { // retrieve the extension $ pos = strrpos ( $ filename , '.' ) ; $ extension = '' ; if ( $ pos !== false ) { $ extension = strtolower ( substr ( $ filename , $ pos + 1 ) ) ; } // if we have an extension, validate it agains the black and white lists if ( $ extension ) { // not in whitelist? if ( sizeof ( $ this -> allowedExtensions ) > 0 && ! in_array ( $ extension , $ this -> allowedExtensions ) ) { return false ; } // in blacklist ? if ( sizeof ( $ this -> deniedExtensions ) && in_array ( $ extension , $ this -> deniedExtensions ) ) { return false ; } } elseif ( sizeof ( $ this -> allowedExtensions ) > 0 ) { // no extension given, thus not in the whitelist! return false ; } return true ; }
Check if the extension  of the given filename is allowed.

@param string $filename
@return boolean
Check if the extension of the given filename is allowed .