Struct Ring 

pub struct Ring<'a, T> { /* private fields */ }

A hashing ring implemented using maglev hashing.

Maglev hashing produces a lookup table that allows finding a node in constant time by generating random permutations.

Examples

use hash_rings::maglev::Ring;

let ring = Ring::new(vec![&"node-1", &"node-2", &"node-3"]);

assert_eq!(ring.get_node(&"point-1"), &"node-3");
assert_eq!(ring.nodes(), 3);
assert_eq!(ring.capacity(), 307);

Implementations

impl<'a, T> Ring<'a, T>

pub fn new(nodes: Vec<&'a T>) -> Self

where T: Hash,

Constructs a new Ring<T> with a specified list of nodes.

Examples

use hash_rings::maglev::Ring;

let ring = Ring::new(vec![&"node-1", &"node-2", &"node-3"]);

pub fn with_capacity_hint(nodes: Vec<&'a T>, capacity_hint: usize) -> Self

where T: Hash,

Constructs a new Ring<T> with a specified list of nodes and a capacity hint. The actual capacity of the ring will always be the next prime greater than or equal to capacity_hint. If nodes are removed and the ring is regenerated, the ring should be rebuilt with the same capacity.

Examples

use hash_rings::maglev::Ring;

let ring = Ring::with_capacity_hint(vec![&"node-1", &"node-2", &"node-3"], 100);
assert_eq!(ring.capacity(), 101);

pub fn nodes(&self) -> usize

Returns the number of nodes in the ring.

Examples

use hash_rings::maglev::Ring;

let ring = Ring::new(vec![&"node-1", &"node-2", &"node-3"]);
assert_eq!(ring.nodes(), 3);

pub fn capacity(&self) -> usize

Returns the capacity of the ring. If nodes are removed and the ring is regenerated, the ring should be rebuilt with the same capacity.

Examples

use hash_rings::maglev::Ring;

let ring = Ring::new(vec![&"node-1", &"node-2", &"node-3"]);
assert_eq!(ring.capacity(), 307);

pub fn get_node<U>(&self, key: &U) -> &T

where U: Hash,

Returns the node associated with a key.

Examples

use hash_rings::maglev::Ring;

let ring = Ring::new(vec![&"node-1", &"node-2", &"node-3"]);
assert_eq!(ring.get_node(&"point-1"), &"node-3");

pub fn iter(&'a self) -> impl Iterator<Item = &'a T>

Returns an iterator over the ring. The iterator will yield the nodes in the ring.

Examples

use hash_rings::maglev::Ring;

let ring = Ring::new(vec![&"node-1", &"node-2", &"node-3"]);

let mut iterator = ring.iter();
assert_eq!(iterator.next(), Some(&"node-1"));
assert_eq!(iterator.next(), Some(&"node-2"));
assert_eq!(iterator.next(), Some(&"node-3"));
assert_eq!(iterator.next(), None);

Trait Implementations

impl<'a, T> IntoIterator for &'a Ring<'a, T>

where T: Hash + Eq,

type IntoIter = Box<dyn Iterator<Item = &'a T> + 'a>

Which kind of iterator are we turning this into?

type Item = &'a T

The type of the elements being iterated over.

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.