Copyright is enough to cover software from being stolen by another company.
Right now we are in de ridicules situations that a single piece of software is covered by three different property rights:
- Copyright, which covers the original source code and binary as a work of art/craft.
- Trade secret, because most software is only released in binary form.
- Patent, which oddly for software does not break the trade secret because they mostly cover ideas instead of implementation or are written in such a way that one skilled in the art can't recreate the implementation from the patent.
In other fields you have to choose one, and only one, of these rights.
- The formula for Coca Cola cannot be copyrighted, they don't want to patent it because it only last for a few years, so they have a trade secret they protect.
- The song Happy Birthday is copyrighted, there are no patents for the order of notes in the music, nor can it be a trade secret on how to sing Happy Birthday.
- The cap of a shampoo bottle, can't be copyrighted, a trade secret is useless because everyone can see it, so they opted for a patent.