Benchmarking SPL Iterators vs for / foreach ???

Hi, Someone have benchmarked SPL iterators vs for / foreach loops? What is the performance penalty? SPL is ¨interpreted wrapper¨ on the top of C++ STL (correct me if I am wrong), and I am sure it uses STL callbacks. But unlike C++, PHP scripts are interpreted, so pointer arithmetic will work only through Zend engine which for sure adds extra performance penalty. Thanks in advance for any suggestion(s) ************************************************ ***   with best regards ***   Andrei Verovski (aka MacGuru) ***   Mac, Linux, DTP, Programming Web Site *** ***   http://snow.prohosting.com/guru4mac/ ************************************************