/**
 * Add a unified diff file to the patcher
 *
 * @param   string   $filename  Path to the unified diff file
 * @param   string   $root      The files root path
 * @param   integer  $strip     The number of '/' to strip
 *
 * @return  Patcher  $this for chaining
 *
 * @since   3.0.0
 */
public function addFile($filename, $root = JPATH_BASE, $strip = 0)
{
    return $this->add(file_get_contents($filename), $root, $strip);
}