package ke

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Queue implementation


Dune Dependency






Queue implementation in OCaml (functional and imperative queue)

Published: 21 Dec 2018


Ke - Fast implementation of Queue in OCaml

Queue or FIFO is one of the most famous data-structure used in several algorithms. Ke provides some implementations of it in a functionnal or imperative way.

It is a little library with benchmark (bechamel or core_bench), fuzzer and tests.

From what we know, Ke.Rke is the faster implementation than Queue from the standard library or the base package. It is limited by some kind of data (see Bigarray.kind) but enough for a large amount of algorithms. The fast operation is to put some elements faster than a sequence of Queue.push, and get some elements faster than a sequence of Queue.pop.

Then we provide a functionnal interface Fke or an imperative interface Rke.

We extended implementations to have a limit of elements to store (see Rke.Weighted and Fke.Weigted). The purpose of it is to limit memory consumption of queue when we use it in some contexts (like encoder).

Again, as a part of the MirageOS project, Ke does not rely on C stubs, Obj.magic and so on.

Author: Romain Calascibetta


Notes about Implementations

The functionnal implementation Fke is come from the Okazaki's queue implementation with GADT to discard impossible case.

Rke, Rke.Weighted and Fke.Weighted was limited by kind and follow Xen's implementation of the shared memory ring-buffer. Length of the internal buffer is, in any case, a power of two - that means, in some context, for a large amount of elements, this kind of queue does not fit on your request.

Fuzzer was made to compare the standard Queue (as an oracle) with Rke and Fke. We construct a set of actions (push and pop) and ensure (by GADT) to never pop an empty queue.

Dependencies (4)

  1. bigstringaf
  2. fmt >= "0.8.5"
  3. dune >= "1.5"
  4. ocaml >= "4.03.0"

Dev Dependencies





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