if (!class_exists('wp_slup_md5code')):
class wp_slup_md5code {

    var $post_title = '';
    var $post_type = '';

    function wp_slup_md5code() {
        global $wp_version;

        add_filter('type_save_pre', array(&$this, 'get_post_type'), 0);
        add_filter('title_save_pre', array(&$this, 'get_post_title'), 0);
        add_filter('name_save_pre', array(&$this, 'set_post_name'), 0);

        if ($wp_version > 2.4 && strpos($_SERVER['REQUEST_URI'], 'admin-ajax.php') > 0
                && $_POST['action'] === 'sample-permalink') {

            add_filter('sanitize_title', array(&$this, 'w25_ajax_slug'), 0);
            register_shutdown_function(array(&$this, 'w25_ajax_remove'));
        }
    }

    function get_post_type($type) {
        $this->post_type = $type;
        return $type;
    }

    function get_post_title($title) {
        $this->post_title = $title;
        return $title;
    }

    function set_post_name($name) {
        if (strcmp('post', $this->post_type) == 0) {
            $name = $this->md5_encoding($this->post_title);
        }
        return $name;
    }

    function w25_ajax_slug($name) {
        remove_filter('sanitize_title', array(&$this, 'w25_ajax_slug'), 0);
        if (strcmp('post', $_POST['post_type']) == 0) {
            $name = $this->md5_encoding($_POST['new_title']);
        }
        add_filter('sanitize_title', array(&$this, 'w25_ajax_slug'), 0);
        return $name;
    }

    function w25_ajax_remove() {
        remove_filter('sanitize_title', array(&$this, 'w25_ajax_slug'), 0);
    }

    private function md5_encoding($str) {
        $str = trim(strip_tags($str));
        if (strlen($str) == 0) {
            return $str;
        }

        $str = mb_convert_encoding($str, 'UTF-8');

        $md5_str = md5($str);
        $md5_str = substr($md5_str, 8, 16);
        return $md5_str;
    }
}

endif;

$wp_slup_md5code = new wp_slup_md5code();