Drupal redirection

I am working on a project and there is a custom module in that which have the drupal redirection code in it here is the code :

if (empty($_GET['destination'])
&& isset($_COOKIE["abc"])
&& $_COOKIE["abc"]<>''
&& ($_POST['form_id'] != 'user_pass_reset'))
  {
   $_GET['destination'] = "xyz" ;
  }
}

Can anyone please explain the 3rd line of code or maybe all of it. Thanks

I have added comments to the source. <> is the same as !=. See PHP Comparison Opperators.

if (empty($_GET['destination']) //Check if $_GET['destination'] is empty.
&& isset($_COOKIE["abc"]) //Check if $_COOKIE["abc"] is not NULL.
&& $_COOKIE["abc"]<>'' //Check if $_COOKIE["abc"] does not equal an empty string.
&& ($_POST['form_id'] != 'user_pass_reset')) //Check if $_POST['form_id'] is not 'user_pass_reset'
  {
   $_GET['destination'] = "xyz" ; //Set $_GET['destination'] to "xyz"
  }
}