Using Zend Framework 1 library in Laminas API tools - auto loading vendor prefix class

Question

I am working on a Laminas API tools (version 1.4) project. There is ZF1 library which I need in my code. the structure of library is:

DirectoryA
          .DirectoryB
            file1.php =====> DirectoryA_DirectoryA_className

as shown above class names are vendor prefix.

when I use this class in my code the use statement is like below:

use DirectoryA_DirectoryA_className

but in runtime I get Class DirectoryA_DirectoryA_className not found error.

my autoloading config in composer.json file:

 "autoload": {
   "psr-0": {
     "DirectoryA_": "/lib/DirectoryA/DirectoryB" 
   }
 },

also tried "DirectoryA_": "/lib/DirectoryA" ,"DirectoryA_": "/lib"

I am new in PHP, any help would be appreciated.