This crate provides collections (sets and maps) that wrap SmallVec.
It happens very frequently that you have collections that have on average just a very small number of elements. If you know the maximum size or even the maximum typical size in advance, you can use this crate to store such collections without allocations. For a larger number of elements, the underlying SmallVec will allocate the elements on the heap as a single allocation.
Another very frequent pattern is that you have a possibly large collection that is being created once and then used readonly for a long time. E.g. lookup tables. In these cases, ease of adding individual new elements is less important than compact in-memory representation and lookup performance. This crate provides succinct collections that have only a very small constant overhead over the contents of the collections.
Performance for bulk creation as well as lookup is better than BTreeMap/BTreeSet and comparable with HashMap/HashSet for types with a cheap Ord instance, like primitive types, and small to medium sizes. Performance for insertion or removal of individual elements to/from large collections is bad, however. This is not the intended use case.
Provides a set backed by a SmallVec of elements.
Provides a map backed by a SmallVec of key value pairs.
A VecSet with an additional flag so it can support negation. This way it is possible to represent e.g. the set of all u64 except 1.
A VecMap with an additional default value, so lookup is a total function.
The in place operations use unsafe code. If that is a problem for you, let me know and I can hide them behind a feature.
A map backed by a SmallVec of key value pairs.
A set backed by a SmallVec of elements.
An interator that is guaranteed to be sorted by item
Types that can be used as the backing store for a SmallVec
set operations for iterators where the items are sorted according to the natural order
relational operations for iterators of pairs where the items are sorted according to the key
Type alias for a VecMap with up to 1 mapping with inline storage.
Type alias for a VecSet with up to 2 elements with inline storage.