Struct std::hash::BuildHasherDefault

pub struct BuildHasherDefault<H>(_);

The BuildHasherDefault structure is used in scenarios where one has a type that implements Hasher and Default, but needs that type to implement BuildHasher.

This structure is zero-sized and does not need construction.

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>

fn default() -> BuildHasherDefault<H>

Returns the "default value" for a type.

impl<H> Clone for BuildHasherDefault<H>

fn clone(&self) -> BuildHasherDefault<H>

Returns a copy of the value.

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

Performs copy-assignment from source.

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

type Hasher = H

Type of the hasher that will be created.

fn build_hasher(&self) -> H

Creates a new hasher.

impl<H> Debug for BuildHasherDefault<H>

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

Formats the value using the given formatter.