Periodic: datastructures over a lattice

The dual space of a lattice is periodic, meaning that it is bounded and, reaching those boundaries, one returns to the starting point. A tipical (non-trivial) example of a periodic space is a sphere: choose a direction and go straight: you will always return to the starting point.

This analogy aims to describe how this crate is conceived and what purpose it serves: it offers two modules, ring, that expose implementation of periodic Vec-like structs, and map, that offers a HashMap-like struct that overwrites its key-value pairs after a certain capacity has been reached.

What?

If you want to use this library in your project, you can add this to your cargo dependencies:

periodic-rs = "0.2.1"

Why?

What are these structures for? Their main use is to have caches that occupy a constant amount of slots of memory, being therefore limited in the amount of consumed memory, but a cache of a very simplistic nature: first-in-first-overwritten-when-full.

Of course, the real underlying reason for the author to create this work was to learn some rust.

How?

The simplest api of this package is the following:

use periodic::map::RingDict;

// 3 is the total capacity
let mut rd: RingDict<&str, i32> = RingDict::new(3);
rd.insert("a", 1);
rd.insert("b", 2);
rd.insert("c", 3);
assert_eq!(rd.get("a"), Some(&1));
assert_eq!(rd.get("b"), Some(&2));
assert_eq!(rd.get("c"), Some(&3));

// Now we add a new key-value pair, overcoming the capacity
rd.insert("d", 4);
assert_eq!(rd.get("d"), Some(&4));
assert!(rd.get("a").is_none());

Contacts

You can email the author at:

blallo -|AT|- autistici -dot- org