【CodeIgniter3】フックを使ってコントローラーを拡張するクラスを複数作成する方法

CI_Classes.php

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

class CI_Classes
{
    private $_include_paths = array();

    public function register(array $paths = array())
    {
        $this->_include_paths = $paths;
        spl_autoload_register(array($this, "autoloader"));
    }

    public function autoloader($class)
    {
        foreach ($this->_include_paths as $path) {
            $filepath = $path . $class . ".php";
            if(!class_exists($class, FALSE) AND is_file($filepath)) {
                include_once ($filepath);
                break;
            }
        }
    }
}