BuildHasherDefault in std::hash - Rust (original) (raw)
Struct BuildHasherDefault
1.0.0 · Source
pub struct BuildHasherDefault<H>(/* private fields */);Expand description
Used to create a default BuildHasher instance for types that implementHasher and Default.
BuildHasherDefault<H> can be used when a type H implements Hasher andDefault, and you need a corresponding BuildHasher instance, but none is defined.
Any BuildHasherDefault is zero-sized. It can be created withdefault. When using BuildHasherDefault with HashMap orHashSet, this doesn’t need to be done, since they implement appropriateDefault instances themselves.
§Examples
Using BuildHasherDefault to specify a custom BuildHasher forHashMap:
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();1.85.0 (const: 1.85.0) · Source
Creates a new BuildHasherDefault for Hasher H.
Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.