asiahighlights.com/application/third_party/ip2location/controllers/index.php

<?php

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

class Index extends CI_Controller
{

    public function __construct()
    {
        parent::__construct();
        $this->load->model('Ip2location_db1_model');
    }

    public function index()
    {
        $data = array();
        //优先读取参数ip地址，没有则自动判断客户端地址
        $data['ip_address'] = $this->input->get_post('ip_address');
        if (empty($data['ip_address'])) {
            $data['ip_address'] = $this->input->ip_address();
        }
        $data['ip_number'] = $this->Dot2LongIP($data['ip_address']);
        $data['country_code'] = $this->Ip2location_db1_model->get_country_code($data['ip_number']);
        echo json_encode($data);
    }

    function Dot2LongIP($IPaddr)
    {
        if ($IPaddr == "") {
            return 0;
        } else {
            $ips = explode(".", "$IPaddr");
            return ($ips[3] + $ips[2] * 256 + $ips[1] * 256 * 256 + $ips[0] * 256 * 256 * 256);
        }
    }

}