SimplePie_Misc::strip_comments PHP Method

    function strip_comments($data)
    {
        $output = '';
        while (($start = strpos($data, '<!--')) !== false) {
            $output .= substr($data, 0, $start);
            if (($end = strpos($data, '-->', $start)) !== false) {
                $data = substr_replace($data, '', 0, $end + 3);
            } else {
                $data = '';
            }
        }
        return $output . $data;
    }

 public function sanitize($data, $type, $base = '')
 {
     $data = trim($data);
     if ($data !== '' || $type & SIMPLEPIE_CONSTRUCT_IRI) {
         if ($type & SIMPLEPIE_CONSTRUCT_MAYBE_HTML) {
             if (preg_match('/(&(#(x[0-9a-fA-F]+|[0-9]+)|[a-zA-Z0-9]+)|<\\/[A-Za-z][^\\x09\\x0A\\x0B\\x0C\\x0D\\x20\\x2F\\x3E]*' . SIMPLEPIE_PCRE_HTML_ATTRIBUTE . '>)/', $data)) {
                 $type |= SIMPLEPIE_CONSTRUCT_HTML;
             } else {
                 $type |= SIMPLEPIE_CONSTRUCT_TEXT;
             }
         }
         if ($type & SIMPLEPIE_CONSTRUCT_BASE64) {
             $data = base64_decode($data);
         }
         if ($type & SIMPLEPIE_CONSTRUCT_XHTML) {
             if ($this->remove_div) {
                 $data = preg_replace('/^<div' . SIMPLEPIE_PCRE_XML_ATTRIBUTE . '>/', '', $data);
                 $data = preg_replace('/<\\/div>$/', '', $data);
             } else {
                 $data = preg_replace('/^<div' . SIMPLEPIE_PCRE_XML_ATTRIBUTE . '>/', '<div>', $data);
             }
         }
         if ($type & (SIMPLEPIE_CONSTRUCT_HTML | SIMPLEPIE_CONSTRUCT_XHTML)) {
             if ($this->strip_comments) {
                 $data = SimplePie_Misc::strip_comments($data);
             }
             if ($this->strip_htmltags) {
                 foreach ($this->strip_htmltags as $tag) {
                     $pcre = "/<({$tag})" . SIMPLEPIE_PCRE_HTML_ATTRIBUTE . "(>(.*)<\\/{$tag}" . SIMPLEPIE_PCRE_HTML_ATTRIBUTE . '>|(\\/)?>)/siU';
                     while (preg_match($pcre, $data)) {
                         $data = preg_replace_callback($pcre, array(&$this, 'do_strip_htmltags'), $data);
                     }
                 }
             }
             if ($this->strip_attributes) {
                 foreach ($this->strip_attributes as $attrib) {
                     $data = preg_replace('/(<[A-Za-z][^\\x09\\x0A\\x0B\\x0C\\x0D\\x20\\x2F\\x3E]*)' . SIMPLEPIE_PCRE_HTML_ATTRIBUTE . trim($attrib) . '(?:\\s*=\\s*(?:"(?:[^"]*)"|\'(?:[^\']*)\'|(?:[^\\x09\\x0A\\x0B\\x0C\\x0D\\x20\\x22\\x27\\x3E][^\\x09\\x0A\\x0B\\x0C\\x0D\\x20\\x3E]*)?))?' . SIMPLEPIE_PCRE_HTML_ATTRIBUTE . '>/', '\\1\\2\\3>', $data);
                 }
             }
             $this->base = $base;
             foreach ($this->replace_url_attributes as $element => $attributes) {
                 $data = $this->replace_urls($data, $element, $attributes);
             }
             if (isset($this->image_handler) && (string) $this->image_handler !== '' && $this->enable_cache) {
                 $images = SimplePie_Misc::get_element('img', $data);
                 foreach ($images as $img) {
                     if (isset($img['attribs']['src']['data'])) {
                         $image_url = call_user_func($this->cache_name_function, $img['attribs']['src']['data']);
                         $cache = call_user_func(array($this->cache_class, 'create'), $this->cache_location, $image_url, 'spi');
                         if ($cache->load()) {
                             $img['attribs']['src']['data'] = $this->image_handler . $image_url;
                             $data = str_replace($img['full'], SimplePie_Misc::element_implode($img), $data);
                         } else {
                             $file = new $this->file_class($img['attribs']['src']['data'], $this->timeout, 5, array('X-FORWARDED-FOR' => $_SERVER['REMOTE_ADDR']), $this->useragent, $this->force_fsockopen);
                             $headers = $file->headers;
                             if ($file->success && ($file->method & SIMPLEPIE_FILE_SOURCE_REMOTE === 0 || ($file->status_code === 200 || $file->status_code > 206 && $file->status_code < 300))) {
                                 if ($cache->save(array('headers' => $file->headers, 'body' => $file->body))) {
                                     $img['attribs']['src']['data'] = $this->image_handler . $image_url;
                                     $data = str_replace($img['full'], SimplePie_Misc::element_implode($img), $data);
                                 } else {
                                     trigger_error("{$this->cache_location} is not writeable. Make sure you've set the correct relative or absolute path, and that the location is server-writable.", E_USER_WARNING);
                                 }
                             }
                         }
                     }
                 }
             }
             $data = trim($data);
         }
         if ($type & SIMPLEPIE_CONSTRUCT_IRI) {
             $data = SimplePie_Misc::absolutize_url($data, $base);
         }
         if ($type & (SIMPLEPIE_CONSTRUCT_TEXT | SIMPLEPIE_CONSTRUCT_IRI)) {
             $data = htmlspecialchars($data, ENT_COMPAT, 'UTF-8');
         }
         if ($this->output_encoding !== 'UTF-8') {
             $data = SimplePie_Misc::change_encoding($data, 'UTF-8', $this->output_encoding);
         }
     }
     return $data;
 }