compute ink consumption / Save a copy of each printed files

[Bobby]

Hello

I would like to compute ink consumption for each file printed throw cups server.

I would like to add a functionality to cups in order to save each printed document into a file.

Then, i would write a cron job that will open those files and compute ink consumption and delete the file.

I don t know where to start.

Can anyone tell me which entry point in cups source code will give me access to each printed document ?

Thanks

Bob