Controller : Upload File Menggunakan CodeIgniter

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');

class uploadfile extends CI_Controller {

    function __construct() {
        parent::__construct();
        $this->load->helper(array('form', 'url'));
        $this->load->library('upload');
    }

    function index() {
        $this->load->view('uploadfile');
    }

    function do_upload() {
        $config = array(
            'upload_path' => './resources/uploads'
            , 'allowed_types' => 'gif|jpg|png'
            , 'max_size' => '1000000000'
            , 'max_width' => '2048'
            , 'max_height' => '1024'
        );

        $this->upload->initialize($config);

        $pic = '';

        if (isset($_FILES["userfile"]["name"])) {
            if (!$this->upload->do_upload()) {

            } else {
                $tGambar = $this->upload->data();
                $pic = $tGambar["file_name"];
            }
        } else {
            $pic = '';
        }
        print_r($pic);
    }

}

?>