[vitus]

> std::deque will never beat your hand-rolled ring buffer.

std::deque may never beat a hand-rolled ring buffer of fixed size that maintains cursors, but it will beat a hand-rolled linked-list implementation.

The typical implementation will generally exhibit better cache locality than a linked list, and will outperform it for random access as required by the specification (amortized constant, vs linear).

(The typical implementation per cppreference, although I don't think this is formally required by the spec, is a sequence of fixed-length arrays.)