function _call_hook($which = '')
 {
  if ( ! $this->enabled OR ! isset($this->hooks[$which])) // 에러발생라인
  {
   return FALSE;
  }

  if (isset($this->hooks[$which][0]) AND is_array($this->hooks[$which][0]))
  {
   foreach ($this->hooks[$which] as $val)
   {
    $this->_run_hook($val);
   }
  }
  else
  {
   $this->_run_hook($this->hooks[$which]);
  }

  return TRUE;
 }

function _set_routing()
 {
  // Are query strings enabled in the config file?  Normally CI doesn't utilize query strings
  // since URI segments are more search-engine friendly, but they can optionally be used.
  // If this feature is enabled, we will gather the directory/class/method a little differently
  $segments = array();
  if ($this->config->item('enable_query_strings') === TRUE AND isset($_GET[$this->config->item('controller_trigger')]))
  {
   if (isset($_GET[$this->config->item('directory_trigger')]))
   {
    $this->set_directory(trim($this->uri->_filter_uri($_GET[$this->config->item('directory_trigger')])));
    $segments[] = $this->fetch_directory();
   }

   if (isset($_GET[$this->config->item('controller_trigger')]))
   {
    $this->set_class(trim($this->uri->_filter_uri($_GET[$this->config->item('controller_trigger')])));
    $segments[] = $this->fetch_class();
   }

   if (isset($_GET[$this->config->item('function_trigger')]))
   {
    $this->set_method(trim($this->uri->_filter_uri($_GET[$this->config->item('function_trigger')])));
    $segments[] = $this->fetch_method();
   }
  }

  // Load the routes.php file.
  if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/routes.php'))
  {
   include(APPPATH.'config/'.ENVIRONMENT.'/routes.php');
  }
  elseif (is_file(APPPATH.'config/routes.php'))
  {
   include(APPPATH.'config/routes.php');
  }
  
  $this->routes = ( ! isset($route) OR ! is_array($route)) ? array() : $route;
  unset($route);

  // Set the default controller so we can display it in the event
  // the URI doesn't correlated to a valid controller.
  $this->default_controller = ( ! isset($this->routes['default_controller']) OR $this->routes['default_controller'] == '') ? FALSE : strtolower($this->routes['default_controller']);

  // Were there any query string segments?  If so, we'll validate them and bail out since we're done.
  if (count($segments) > 0)
  {
   return $this->_validate_request($segments);
  }

  // Fetch the complete URI string
  $this->uri->_fetch_uri_string();

  // Is there a URI string? If not, the default controller specified in the "routes" file will be shown.
  if ($this->uri->uri_string == '')
  {
   return $this->_set_default_controller();
  }

  // Do we need to remove the URL suffix?
  $this->uri->_remove_url_suffix();

  // Compile the segments into an array
  $this->uri->_explode_segments();

  // Parse any custom routing that may exist
  $this->_parse_routes();

  // Re-index the segment array so that it starts with 1 rather than 0
  $this->uri->_reindex_segments();
 }