<?php



/**

 * W3 CDN Class

 */



if (!defined('W3_CDN_FTP')) {

    define('W3_CDN_FTP', 'ftp');

}



if (!defined('W3_CDN_CF')) {

    define('W3_CDN_CF', 'cf');

}



if (!defined('W3_CDN_S3')) {

    define('W3_CDN_S3', 's3');

}



if (!defined('W3_CDN_MIRROR')) {

    define('W3_CDN_MIRROR', 'mirror');

}



if (!defined('W3_CDN_NETDNA')) {

    define('W3_CDN_NETDNA', 'netdna');

}



if (!defined('W3_CDN_RSCF')) {

    define('W3_CDN_RSCF', 'rscf');

}



/**

 * Class W3_Cdn

 */

class W3_Cdn

{

    /**

     * Returns W3_Cdn_Base instance

     *

     * @param string $engine

     * @param array $config

     * @return W3_Cdn_Base

     */

    function &instance($engine, $config = array())

    {

        static $instances = array();

        

        $instance_key = sprintf('%s_%s', $engine, md5(serialize($config)));

        

        if (!isset($instances[$instance_key])) {

            switch (true) {

                case ($engine == W3_CDN_FTP) :

                    require_once W3TC_LIB_W3_DIR . '/Cdn/Ftp.php';

                    $instances[$instance_key] = & new W3_Cdn_Ftp($config);

                    break;

                

                case (W3TC_PHP5 && $engine == W3_CDN_S3) :

                    require_once W3TC_LIB_W3_DIR . '/Cdn/S3.php';

                    $instances[$instance_key] = & new W3_Cdn_S3($config);

                    break;

                

                case (W3TC_PHP5 && $engine == W3_CDN_CF) :

                    require_once W3TC_LIB_W3_DIR . '/Cdn/Cf.php';

                    $instances[$instance_key] = & new W3_Cdn_Cf($config);

                    break;

                

                case (W3TC_PHP5 && $engine == W3_CDN_RSCF) :

                    require_once W3TC_LIB_W3_DIR . '/Cdn/Rscf.php';

                    $instances[$instance_key] = & new W3_Cdn_Rscf($config);

                    break;

                

                case ($engine == W3_CDN_MIRROR) :

                    require_once W3TC_LIB_W3_DIR . '/Cdn/Mirror.php';

                    $instances[$instance_key] = & new W3_Cdn_Mirror($config);

                    break;

                

                case ($engine == W3_CDN_NETDNA) :

                    require_once W3TC_LIB_W3_DIR . '/Cdn/Netdna.php';

                    $instances[$instance_key] = & new W3_Cdn_Netdna($config);

                    break;

                

                default :

                    trigger_error('Incorrect CDN engine', E_USER_WARNING);

                    require_once W3TC_LIB_W3_DIR . '/Cdn/Base.php';

                    $instances[$instance_key] = & new W3_Cdn_Base();

                    break;

            }

        }

        

        return $instances[$instance_key];

    }

}