Well, from what I remember from my data structures class, a queue/dequeue has to have O(1) worst case insertion, but otherwise, yeah, it's pretty much the same.

Well, from what I remember from my data structures class, a queue/dequeue has to have O(1) worst case insertion, but otherwise, yeah, it's pretty much the same. But your part made me think, indeed there's no inherent reason for a circular buffer to have a fixed capacity. You could use pretty much the same logic but implement reallocation when it's 100% full, and get most of the benefit of both.