2 releases
0.1.1 | Sep 25, 2024 |
---|---|
0.1.0 | Sep 3, 2023 |
#3 in #linked-hash-map
834 downloads per month
Used in 8 crates
(via veilid-core)
110KB
3K
SLoC
hashlink -- HashMap-like containers that hold their key-value pairs in a user controllable order
This crate is a fork of
linked-hash-map that builds on
top of hashbrown to implement more up
to date versions of LinkedHashMap
LinkedHashSet
, and LruCache
.
One important API change is that when a LinkedHashMap
is used as a LRU cache,
it allows you to easily retrieve an entry and move it to the back OR produce a
new entry at the back without needlessly repeating key hashing and lookups:
let mut lru_cache = LinkedHashMap::new();
let key = "key".to_owned();
// Try to find my expensive to construct and hash key
let _cached_val = match lru_cache.raw_entry_mut().from_key(&key) {
RawEntryMut::Occupied(mut occupied) => {
// Cache hit, move entry to the back.
occupied.to_back();
occupied.into_mut()
}
RawEntryMut::Vacant(vacant) => {
// Insert expensive to construct key and expensive to compute value,
// automatically inserted at the back.
vacant.insert(key.clone(), 42).1
}
};
Or, a simpler way to do the same thing:
let mut lru_cache = LinkedHashMap::new();
let key = "key".to_owned();
let _cached_val = lru_cache
.raw_entry_mut()
.from_key(&key)
.or_insert_with(|| (key.clone(), 42));
This crate contains a decent amount of unsafe code from handling its internal
linked list, and the unsafe code has diverged quite a lot from the original
linked-hash-map
implementation. It currently passes tests under miri and
sanitizers, but it should probably still receive more review and testing, and
check for test code coverage.
Credit
There is a huge amount of code in this crate that is copied verbatim from
linked-hash-map
and hashbrown
, especially tests, associated types like
iterators, and things like Debug
impls.
License
This library is licensed the same as linked-hash-map and hashbrown, it is licensed under either of:
- MIT license LICENSE-MIT or http://opensource.org/licenses/MIT
- Apache License 2.0 LICENSE-APACHE or https://opensource.org/licenses/Apache-2.0
at your option.
Dependencies
~1.5MB
~25K SLoC