为什么Magento中URL-Strings的长度如此不同?

I try to find out, if the current url of an user, is the base url of magento. so i need this 2 functions:

Mage::helper('core/url')->getCurrentUrl()

for the current url and:

Mage::getUrl('',array('_secure'=>true))

for the base url include https.

if i do a var_dump() with the first function it returns:

string(42) "https://www.example.de/folder/index.php/"

and the second:

string(51) "https://www.example.de/folder/index.php/"

you see, the strings are identical, but the string counter is not. Could you explain why, and how could i find out, is the users current site is the base url or default home/mainpage.

okay i found this code:

<?php // IF WE ARE ON HOMEPAGE if( Mage::getSingleton('cms/page')->getIdentifier() == 'home' && Mage::app()->getFrontController()->getRequest()->getRouteName() == 'cms' ) : ?> // Put your homepage-only code in here. <?php endif; ?>

on http://www.philowen.co/blog/check-homepage-php-magento/

that's my solution now, but i still cant't explain the different sizes.