cuckoocache

This Library provides a cuckoocache data structure in rust, similar to the one used in Bitcoin.

Cuckoocache is a great candidate for a signature cache store.

Summary:

1. bitpacked is bit-packed atomic flags for garbage collection
2. cache is a cache which is performant in memory usage and lookup speed. It is lockfree for erase operations. Elements are lazily erased on the next insert.

bit_packed::atomic::Flags implements a container for garbage collection flags that is only thread unsafe on calls to setup. This class bit-packs collection flags for memory efficiency.

All operations are Ordering::Relaxed so external mechanisms must ensure that writes and reads are properly synchronized.

On Cache::setup(n), all bits up to n are marked as collected.

Under the hood, because it is an 8-bit type, it makes sense to use a multiple of 8 for setup, but it will be safe if that is not the case as well.