Struct HashHasherBuilder 

pub struct HashHasherBuilder { /* private fields */ }

Available on crate feature rand and neither target_os=solana nor BPF only.

A builder for faster, but less collision resistant hasher for hashes.

Initializes HashHasher instances that use an 8-byte slice of the hash as the hash value. Should not be used when collisions might be used to mount DOS attacks.

Using this results in about 4x faster lookups in a typical hashmap.

Implementations

impl HashHasherBuilder

pub fn with_offset(offset: usize) -> Self

Constructs a builder with a specific offset.

Prefer HashHasherBuilder::default() unless deterministic results are required.

pub fn offset(&self) -> usize

Returns the offset used to construct this builder.

Trait Implementations

impl BuildHasher for HashHasherBuilder

type Hasher = HashHasher

Type of the hasher that will be created.

fn build_hasher(&self) -> Self::Hasher

Creates a new hasher.

fn hash_one<T>(&self, x: T) -> u64

where T: Hash, Self: Sized, Self::Hasher: Hasher,

Calculates the hash of a single value.

impl Clone for HashHasherBuilder

fn clone(&self) -> HashHasherBuilder

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for HashHasherBuilder

fn default() -> Self

Default construct the HashHasherBuilder.

The position of the slice is determined initially through random draw and then by incrementing a thread-local This way each hashmap can be expected to use a slightly different slice. This is essentially the same mechanism as what is used by RandomState