Struct std::hash::BuildHasherDefault1.7.0[][src]

pub struct BuildHasherDefault<H>(_);

Used to create a default BuildHasher instance for types that implement Hasher and Default.

BuildHasherDefault<H> can be used when a type H implements Hasher and Default, and you need a corresponding BuildHasher instance, but none is defined.

Any BuildHasherDefault is zero-sized. It can be created with default. When using BuildHasherDefault with HashMap or HashSet, this doesn’t need to be done, since they implement appropriate Default instances themselves.


Using BuildHasherDefault to specify a custom BuildHasher for HashMap:

use std::collections::HashMap;
use std::hash::{BuildHasherDefault, Hasher};

struct MyHasher;

impl Hasher for MyHasher {
    fn write(&mut self, bytes: &[u8]) {
        // Your hashing algorithm goes here!

    fn finish(&self) -> u64 {
        // Your hashing algorithm goes here!

type MyBuildHasher = BuildHasherDefault<MyHasher>;

let hash_map = HashMap::<u32, u32, MyBuildHasher>::default();

Trait Implementations

impl<H> BuildHasher for BuildHasherDefault<H> where
    H: Default + Hasher

type Hasher = H

Type of the hasher that will be created.

impl<H> Clone for BuildHasherDefault<H>[src]

impl<H> Debug for BuildHasherDefault<H>1.9.0[src]

impl<H> Default for BuildHasherDefault<H>[src]

impl<H> Eq for BuildHasherDefault<H>1.29.0[src]

impl<H> PartialEq<BuildHasherDefault<H>> for BuildHasherDefault<H>1.29.0[src]

Auto Trait Implementations

impl<H> RefUnwindSafe for BuildHasherDefault<H> where
    H: RefUnwindSafe

impl<H> Send for BuildHasherDefault<H> where
    H: Send

impl<H> Sync for BuildHasherDefault<H> where
    H: Sync

impl<H> Unpin for BuildHasherDefault<H> where
    H: Unpin

impl<H> UnwindSafe for BuildHasherDefault<H> where
    H: UnwindSafe

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized

impl<T> Borrow<T> for T where
    T: ?Sized

impl<T> BorrowMut<T> for T where
    T: ?Sized

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 

impl<T> ToOwned for T where
    T: Clone

type Owned = T

The resulting type after obtaining ownership.

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.