tinyset
contains a few collections that are optimized to scale
in size well for small numbers of elements, while still scaling
well in time (and size) for numbers of elements. We have two set types:
Set
is basically interchangeable with HashSet
, although it
does require that its elements implement the Copy
trait,
since otherwise I would have to learn to write correct unsafe
code, which would be scary. It uses FNV hashing when there are
large numbers of elements.
TinySet
is places a stronger requirement on its elements,
which must have trait HasInvalid
. This is intended for
elements that are Copy
, are Hash
, and have an "invalid"
value. For the unsigned integer types, we take their maximum
value to mean invalid. This constraint allows us to save a
bit more space.
Both of these set types will do no heap allocation for small sets of
small elements. TinySet
will store up to 16 bytes of elements
before doing any heap allocation, while Set
stores sets up to size 8
without allocation. Both sets are similar in speed to fnv::HashSet
.
To run the benchmark suite, cd
into bench
and then run
cargo +nightly run --release
This ought to work, provided you've got the nightly rust installed with rustup.