Converting C source to C++

Question

How would you go about converting a reasonably large (>300K), fairly mature C codebase to C++?

The kind of C I have in mind is split into files roughly corresponding to

Answer 1

Your application has lots of folks working on it, and a need to not-be-broken. If you are serious about large scale conversion to an OO style, what you need is massive transformation tools to automate the work.

The basic idea is to designate groups of data as classes, and then get the tool to refactor the code to move that data into classes, move functions on just that data into those classes, and revise all accesses to that data to calls on the classes.

You can do an automated preanalysis to form statistic clusters to get some ideas, but you'll still need an applicaiton aware engineer to decide what data elements should be grouped.

A tool that is capable of doing this task is our DMS Software Reengineering Toolkit. DMS has strong C parsers for reading your code, captures the C code as compiler abstract syntax trees, (and unlike a conventional compiler) can compute flow analyses across your entire 300K SLOC. DMS has a C++ front end that can be used as the "back" end; one writes transformations that map C syntax to C++ syntax.

A major C++ reengineering task on a large avionics system gives some idea of what using DMS for this kind of activity is like. See technical papers at www.semdesigns.com/Products/DMS/DMSToolkit.html, specifically Re-engineering C++ Component Models Via Automatic Program Transformation

This process is not for the faint of heart. But than anybody that would consider manual refactoring of a large application is already not afraid of hard work.

Yes, I'm associated with the company, being its chief architect.