generational-cache
Generational Arena based cache impls. in 100% safe, [no_std] compatible Rust.
## Usage `generational-cache` is a library crate. You may include it in your `Cargo.toml` as follows: ```toml [dependencies] generational-cache = "0.2.2" ``` Refer to latest git [API Documentation](https://arindas.github.io/generational-cache/docs/generational_cache/) or [Crate Documentation](https://docs.rs/generational-cache) for more details. ### Examples 1. LRU Cache (`generational_cache::cache::LRUCache`) A generational arena based LRU cache implementation. ```rust #[no_std] use generational_cache::prelude::*; const CAPACITY: usize = 3; // users can choose between different map and vector implementations let mut cache = LRUCache::<_, i32, u64, AllocBTreeMap<_, _>>::with_backing_vector(Array::<_, CAPACITY>::new()); cache.insert(-1, 1).unwrap(); cache.insert(-2, 2).unwrap(); cache.insert(-3, 3).unwrap(); assert_eq!(cache.least_recent().unwrap(), (&-1, &1)); assert_eq!(cache.most_recent().unwrap(), (&-3, &3)); assert_eq!(cache.insert(-4, 4).unwrap(), Eviction::Block { key: -1, value: 1}); assert_eq!(cache.least_recent().unwrap(), (&-2, &2)); assert_eq!(cache.most_recent().unwrap(), (&-4, &4)); assert_eq!(cache.insert(-2, 42).unwrap(), Eviction::Value(2)); assert_eq!(cache.least_recent().unwrap(), (&-3, &3)); assert_eq!(cache.most_recent().unwrap(), (&-2, &42)); assert_eq!(cache.remove(&-42).unwrap(), Lookup::Miss); assert_eq!(cache.query(&-42).unwrap(), Lookup::Miss); assert_eq!(cache.query(&-3).unwrap(), Lookup::Hit(&3)); assert_eq!(cache.least_recent().unwrap(), (&-4, &4)); assert_eq!(cache.most_recent().unwrap(), (&-3, &3)); assert_eq!(cache.remove(&-2).unwrap(), Lookup::Hit(42)); assert_eq!(cache.query(&-2).unwrap(), Lookup::Miss); // zero capacity LRUCache is unusable let mut cache = LRUCache::<_, i32, u64, AllocBTreeMap<_, _>>::with_backing_vector(Array::<_, 0_usize>::new()); match cache.insert(0, 0) { Err(LRUCacheError::ListUnderflow) => {} _ => unreachable!("Wrong error on list underflow."), }; ``` (… we plan on adding more cache implementations in the future). ## License This repository is licensed under the MIT License. See [License](https://raw.githubusercontent.com/arindas/generational-cache/main/LICENSE) for more details.