protected function unzip($directory) {
      $file = $directory . '.zip';
      $fh = Loader::helper('file');
      if (version_compare(phpversion(), '5.3.0', '>=') && function_exists('zip_open')) {
         $zip = new ZipArchive;
         if ($zip->open($fh->getTemporaryDirectory() . '/' . $file) === TRUE) {
            $zip->extractTo($fh->getTemporaryDirectory() . '/' . $directory . '/');
            $zip->close();   
            return $fh->getTemporaryDirectory() . '/' . $directory;
         }         
         throw new Exception(t('There was an error unpacking the file. Perhaps you have not uploaded a valid zip file, or you do not have zip installed.'));         
       } else {
         $ret = @shell_exec(DIR_FILES_BIN_UNZIP . ' ' . $fh->getTemporaryDirectory() . '/' . $file . ' -d ' . $fh->getTemporaryDirectory() . '/' . $directory . '/');
         $files = $this->f->getDirectoryContents($fh->getTemporaryDirectory() . '/' . $directory);
         if (count($files) == 0) {
            throw new Exception(t('There was an error unpacking your file. Perhaps you have not uploaded a valid zip file, or you do not have zip installed.'));
         } else {
            return $fh->getTemporaryDirectory() . '/' . $directory;
         }
      }
   }