Struct core::hash::BuildHasherDefault  1.7.0[−][src]
pub struct BuildHasherDefault<H>(_);Expand description
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
Returns the “default value” for a type. Read more