LRU Cache

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[Documentation]

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 1.56.0.

Example

Below is a simple example of how to instantiate and use a LRU cache.

```rust,no_run 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);

} ```