Sure you can apply. And you might very well get it too. They don't have time to check much at the patent office, mostly standarized IP databases (probably not including your code). And if you get it, it becomes the burden of the others to prove the patent invalid. Bad patents are common, and litigation so expensive that they are a real problem to whoever is affected by them.
Some lawyers argue that if you publish software under an open source license without an explicit patent grant, that their is an implicit grant with it. As far as I know, this has not been tested in court, but it seems reasonable to me, (not as lawyer).