Route to multiple sub folders in CodeIgniter

Ref link : http://stackoverflow.com/questions/5213115/route-to-multiple-sub-folders-in-codeigniter

<?php

/*
 * Custom router function v 0.2
 *
 * Add functionality : read into more than one sub-folder
 *
 */

Class MY_Router extends CI_Router
{
    Function MY_Router()
    {
        parent::__construct();
    }

    function _validate_request($segments)
    {
        if (file_exists(APPPATH.'controllers/'.$segments[0].EXT))
        {
            return $segments;
        }

        if (is_dir(APPPATH.'controllers/'.$segments[0]))
        {
            $this->set_directory($segments[0]);
            $segments = array_slice($segments, 1);

            /* ----------- ADDED CODE ------------ */

            while(count($segments) > 0 && is_dir(APPPATH.'controllers/'.$this->directory.$segments[0]))
            {
                // Set the directory and remove it from the segment array
            //$this->set_directory($this->directory . $segments[0]);
            if (substr($this->directory, -1, 1) == '/')
                $this->directory = $this->directory . $segments[0];
            else
                $this->directory = $this->directory . '/' . $segments[0];

            $segments = array_slice($segments, 1);
            }

            if (substr($this->directory, -1, 1) != '/')
                $this->directory = $this->directory . '/';

            /* ----------- END ------------ */

            if (count($segments) > 0)
            {

                if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().'/'.$segments[0].EXT))
                {
                    show_404($this->fetch_directory().$segments[0]);
                }
            }
            else
            {
                $this->set_class($this->default_controller);
                $this->set_method('index');

                if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().'/' .$this->default_controller.EXT))
                {
                    $this->directory = '';
                    return array();
                }

            }

            return $segments;
        }

        show_404($segments[0]);
    }
}