An implementation of a LRU cache. The cache supports put, get, get_mut and pop operations,
all of which are O(1). This crate was heavily influenced by the LRU Cache implementation in an
earlier version of Rust's std::collections crate.
The MSRV for this crate is 1.70.0.
Below is a simple example of how to instantiate and use a LRU cache.
extern crate lru;
use lru::LruCache;
use std::num::NonZeroUsize;
fn main() {
let mut cache = LruCache::new(NonZeroUsize::new(2).unwrap());
cache.put("apple", 3);
cache.put("banana", 2);
assert_eq!(*cache.get(&"apple").unwrap(), 3);
assert_eq!(*cache.get(&"banana").unwrap(), 2);
assert!(cache.get(&"pear").is_none());
assert_eq!(cache.put("banana", 4), Some(2));
assert_eq!(cache.put("pear", 5), None);
assert_eq!(*cache.get(&"pear").unwrap(), 5);
assert_eq!(*cache.get(&"banana").unwrap(), 4);
assert!(cache.get(&"apple").is_none());
{
let v = cache.get_mut(&"banana").unwrap();
*v = 6;
}
assert_eq!(*cache.get(&"banana").unwrap(), 6);
}