Struct std::hash::BuildHasherDefault

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.

Examples

Using BuildHasherDefault to specify a custom BuildHasher for HashMap:

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

#[derive(Default)]
struct MyHasher;

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

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

type MyBuildHasher = BuildHasherDefault<MyHasher>;

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

Trait Implementations

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

fn default() -> BuildHasherDefault<H> [src]

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

fn clone(&self) -> BuildHasherDefault<H> [src]

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

1.0.0

[src]

impl<H> BuildHasher for BuildHasherDefault<H> where
    H: Default + Hasher,  [src]

type Hasher = H

fn build_hasher(&self) -> H [src]

impl<H> Debug for BuildHasherDefault<H>

1.9.0

[src]

fn fmt(&self, f: &mut Formatter) -> Result<(), Error> [src]