An implementation of a double-ended array-backed deque in Zig, backed by a growable ring buffer.

The Zig standard library is missing a cache-friendly generic FIFO data structure with O(1) push/pop. std.DoublyLinkedList and std.PriorityQueue both offer 2/3 of these benefits, but DoublyLinkedList is not cache-friendly and PriorityQueue has O(logN) push/pop, as well as requiring insertion order to be saved alongside the items to maintain a FIFO structure.

A natural solution to this deficiency is a growable ring buffer in a contiguous slice of memory. At only a slight cost compared to std.ArrayList, O(1) (amortized) push on both ends can be achieved, and items can be accessed with only simple arithmetic and indexing, rather than the O(N) pointer chasing of a linked list.

This library aims to be a robust implementation of such a data structure, drawing heavily from Rust's VecDeque internally, and taking API/semantic cues from Zig's std.ArrayList (for append/pop/slice and similar methods) and std.ArrayHashMap (for iteration and internal buffer management.)