I'm currently working on a certain problem for my company (i.e. where I work for hire and don't own the code I produce in any way). It appears, that in one of my past (or, who knows, maybe still present) personal projects there are a few useful source code files that should help with the problem I'm working on. Neither that personal project nor the company project are open source, and they are not going to become so in foreseeable future.
I would like to import that (small) part of my personal project into the company's source tree. But since I'm not yet calling my project RIP, I'd like to give them the code in the way that I retain my copyright over the code. And, of course, they would need to have the copyright over the code as well - luring them into a trap is definitely not my intention. In that regard I would like to give them any right I can - to modify, run, distribute, use in other projects etc., but not to deprive me of the same rights. And I don't care if that (again, small) part of my project becomes publicly available eventually.
The solution I currently have for this is:
Put the copyright information along with the license into every source code file I'm about to import.
Commit this to my Git repository (hosted privately).
Import the specific files and commit them their repository (hosted as GitHub private repository).
The licensing text I'm using is based on MIT license, but slightly modified (I added the third paragraph), here it is:
So, the questions are:
Most importantly, will this measure protect both parties from the possible legal issues?
Is the fragment I added (the third paragraph) necessary and/or useful? Can it be improved?
Is it a generally good idea to give your own code to your company to speed up development (assuming that my and their projects will never ever compete)?