Relocating the app folder

Hi,

if i relocate the app folder the ROOTPATH will not be created correctly, because it is one folder above the app folder. This is not working if i relocate the app folder:

Root -> app -> this is working

Relocating the app folder:
Root -> codeigniter->app -> this is not working, because the ROOTPATH is codeigniter. This is not correct.

PHP Code:

// The path to the project root directory. Just above APPPATH.
if (! defined('ROOTPATH')) {
    define('ROOTPATH', realpath(APPPATH . '../') . DIRECTORY_SEPARATOR);
} 


I think relocating is not possible or is there any solution?