Maintainability of a python wrapping of a C library

Question

I have a poorly designed and big (> 300 public functions, >200 numeric constants defined with #define in the header file) that I have to wrap in Python. I have the dll and the h file. The library is updated yearly, till now in a backwards compatible way (i.e. just functions were added, a constant keep their numerical values, etc). But I have no guarantees as I do not control the library.

Using ctypes, I see two ways of wrapping this in Python:

1. Mapping every constant and function to python, 1 to 1
2. Redefining the API in Python and making calls to the library.

The first can be done in a (roughly) automatic way from the header file and therefore is easier to maintain and upgrade, the second requires a lot of python code but it will be easier to use.

I would appreciate some opinions based on your experience with this type of problem and some examples.

Answer 1

I recently used ctypesgen to create a ctypes wrapping for SDL, and complementary libraries (SDL_image, SDL_ttf, SDL_mixer).

For me, it worked fairly well. It generates Python 2.x, but I was able to get the desired 3.x code by using the "2to3" utility.

I think it's a good idea to use the ctypes wrapping as a foundation for a more "pythonic" api, and that's basically what I did (on a very simple level) with my pslab module.

So, if you're looking to do something similar, that would be one way.