Consistent Hashing for Rust

Consistent hashing is a special kind of hashing such that when a hash table is resized and consistent hashing is used, only K/n keys need to be remapped on average, where K is the number of keys, and n is the number of slots.

Usage

toml [dependencies] conhash = "*"

```rust extern crate conhash;

use conhash::{ConsistentHash, Node};

[derive(Debug, Clone, Eq, PartialEq)]

struct ServerNode { host: String, port: u16, }

impl Node for ServerNode { fn name(&self) -> String { format!("{}:{}", self.host, self.port) } }

impl ServerNode { fn new(host: &str, port: u16) -> ServerNode { ServerNode { host: host.to_owned(), port: port, } } }

fn main() { let nodes = [ ServerNode::new("localhost", 12345), ServerNode::new("localhost", 12346), ServerNode::new("localhost", 12347), ServerNode::new("localhost", 12348), ServerNode::new("localhost", 12349), ServerNode::new("localhost", 12350), ServerNode::new("localhost", 12351), ServerNode::new("localhost", 12352), ServerNode::new("localhost", 12353), ];

const REPLICAS: usize = 20;

let mut ch = ConsistentHash::new(REPLICAS);

for node in nodes.iter() {
    ch.add(node);
}

assert_eq!(ch.len(), nodes.len() * REPLICAS);

let node_for_hello = ch.get("hello").unwrap().clone();
assert_eq!(node_for_hello, ServerNode::new("localhost", 12347));

ch.remove(&ServerNode::new("localhost", 12350));
assert_eq!(ch.get("hello").unwrap().clone(), node_for_hello);

} ```