# `associative_cache`
**A generic, fixed-size, associative cache data structure mapping `K` keys to
`V` values.**
[![](https://docs.rs/associative-cache/badge.svg)](https://docs.rs/associative-cache/)
[![](https://img.shields.io/crates/v/associative-cache.svg)](https://crates.io/crates/associative-cache)
[![](https://img.shields.io/crates/d/associative-cache.svg)](https://crates.io/crates/associative-cache)
[![](https://github.com/fitzgen/associative-cache/actions/workflows/rust.yml/badge.svg)](https://github.com/fitzgen/associative-cache/actions/workflows/rust.yml)
## Capacity
The cache has a constant, fixed-size capacity which is controlled by the `C`
type parameter and the `Capacity` trait. The memory for the cache entries is
eagerly allocated once and never resized.
## Associativity
The cache can be configured as direct-mapped, two-way associative, four-way
associative, etc... via the `I` type parameter and `Indices` trait.
## Replacement Policy
The cache can be configured to replace the least recently used (LRU) entry, or a
random entry via the `R` type parameter and the `Replacement` trait.
## Examples
```rust
use associative_cache::*;
// A two-way associative cache with random replacement mapping
// `String`s to `usize`s.
let cache = AssociativeCache::<
String,
usize,
Capacity512,
HashTwoWay,
RandomReplacement
>::default();
// A four-way associative cache with random replacement mapping
// `*mut usize`s to `Vec<u8>`s.
let cache = AssociativeCache::<
*mut usize,
Vec<u8>,
Capacity32,
PointerFourWay,
RandomReplacement
>::default();
// An eight-way associative, least recently used (LRU) cache mapping
// `std::path::PathBuf`s to `std::fs::File`s.
let cache = AssociativeCache::<
std::path::PathBuf,
WithLruTimestamp<std::fs::File>,
Capacity128,
HashEightWay,
LruReplacement,
>::default();
```