Best way to create a directory tree on the IFS?

What’s the best way to create a directory tree on the IFS when only some, but perhaps all, of the directory entries exist?

Suppose that the final directory & file will look something like:

/home/PDF/username/2010/03/21/A Report.pdf

I know the /home/PDF/ directory exists, but the username directory may need to be created, as might the 2010 directory, or 03 or 21 before we actually create the .pdf file.

Is the best way to work backwards a directory at a time checking if it exists, then start building forward from there?

In the above example, if only /home/PDF/username/2010/ exists:
Check first for /home/PDF/username/2010/03/21/.
If that doesn’t exist, check for /home/PDF/username/2010/03/.
If that doesn’t exist, check for /home/PDF/username/2010/.
When /home/PDF/username/2010/is found:
Create /home/PDF/username/2010/03.
Create /home/PDF/username/2010/03/21/.

My initial thought is the QHFCRTDR API, which can create only one directory level at a time and caused the above rumination. I’m wondering if there is a better or easier way. Not considering high volume needs, but elegant and easy to use would be nice.