- fixed doxygen comments - replaced O(n) test by O(1) test - simplified code
- fixed doxygen comments
- replaced O(n) test by O(1) test
- simplified code

[r19712]

davidgiven/libfirm,libfirm/libfirm,davidgiven/libfirm,8l/libfirm,libfirm/libfirm,MatzeB/libfirm,davidgiven/libfirm,libfirm/libfirm,8l/libfirm,MatzeB/libfirm,jonashaag/libfirm,davidgiven/libfirm,killbug2004/libfirm,jonashaag/libfirm,libfirm/libfirm,jonashaag/libfirm,killbug2004/libfirm,MatzeB/libfirm,8l/libfirm,davidgiven/libfirm,8l/libfirm,8l/libfirm,MatzeB/libfirm,8l/libfirm,killbug2004/libfirm,killbug2004/libfirm,MatzeB/libfirm,MatzeB/libfirm,jonashaag/libfirm,jonashaag/libfirm,MatzeB/libfirm,davidgiven/libfirm,jonashaag/libfirm,jonashaag/libfirm,davidgiven/libfirm,libfirm/libfirm,killbug2004/libfirm,killbug2004/libfirm,killbug2004/libfirm,8l/libfirm