Extracting common functionality/ OOPL in C

[BelieveRich]

Hi,
Can anyone help me on this?
Right now I have approximately 30 driver files for 30 different devices in .c (each of them have 30 ~ 40 object files dependencies). I am asked to find all the commonalities between the 30 driver files and make it a common.c or common.h. The 30 drivers files are each like 2000 lines long, with a lot of macros, registers assignments, forward declaration and function calls.

Does anyone have any idea how to approach this project?
It would be easier if C is OOPL........
all I can thought of is using struct {} and enum .......
but I don't know what to do with those common functions with little changes in them ...

Any help will be appreciated!!

[weaknessforcats]

Whatever you do, do not change a lot of things at once.

Create an empty common.h and common.c and find one thing to put in there.

Then change the 30 drivers to include your common.h and add the common.c to the builds. Verify the drivers still work.

Then move to the next common thing.

I had this same problem with 280 programs of 4000 lines each. I did manage to identify large areas of duplicated code, the the management was fearful of my changing them and screwing things up. I ended up doing nothing after four months of work.

You might consider doing nothing as an option for these 30 drivers and resolve to use a common.h and common.c on future drivers only.

This will definitely be a judgement call.

[BelieveRich]

This is what I am afraid of.........
The files are so huge with massive dependecies,
I don't want to spend my 4 month and eventually turn out to be nothing useful...
This project has been postponed for 2 years already, and they ask me to finish it....geez!

[weaknessforcats]

Persionally, I wouldn't touch anything that large that is working. I would wait until a replacement project is initiated and then discard the current 30 drivers when that project implements.

Have you done a cost/benefit analysis to show how you can make money by changing a working system and possibly introducing new bugs???

[BelieveRich]

No.....
I think I should..
However I am not familiar with the cost/benefit analysis..
you have any website/demonstration/sample?

[weaknessforcats]

A cost/benefit analysis is just adding up the cost of making all those changes, teseting them and redistriubtung code and comparing that cost to the money you will save by doing that. If you can't save more than it costs, your company loses money. Do that enough and you lose your job.

Are there any project managers where you work? They do this sort of thing all the time.