Caching non-HTML

[eluser]Unknown[/eluser]
I am upgrading to Codeigniter 2.1.2 and could use some help. In version 1.7.0 I had a requirement to cache non-HTML pages (XML and dynamic CSS). Arjen van Bochoven posted a great library extension for CI 1.7.0 to provide expanded cache, but the code does not appear to work in CI 2.1.2. Does anyone have a version for CI 2.1.2 or know how to modify the library extension? The code is a bit beyond my PHP experience, but I am attempting to see what I can do. I have attached the original version for reference.