protected function _getProductListSortByParam( array $params, &$sortdir )
	{
		$sortation = ( isset( $params['f-sort'] ) ? (string) $params['f-sort'] : 'relevance' );

		$sortdir = ( $sortation[0] === '-' ? '-' : '+' );
		$sort = ltrim( $sortation, '-' );

		return ( strlen( $sort ) > 0 ? $sort : 'relevance' );
	}