Struct std::hash::BuildHasherDefault
1.7.0 · source · pub struct BuildHasherDefault<H>(/* private fields */);
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();
RunTrait Implementations§
source§impl<H> BuildHasher for BuildHasherDefault<H>
impl<H> BuildHasher for BuildHasherDefault<H>
source§impl<H> Clone for BuildHasherDefault<H>
impl<H> Clone for BuildHasherDefault<H>
source§fn clone(&self) -> BuildHasherDefault<H>
fn clone(&self) -> BuildHasherDefault<H>
Returns a copy of the value. Read more
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from
source
. Read more1.9.0 · source§impl<H> Debug for BuildHasherDefault<H>
impl<H> Debug for BuildHasherDefault<H>
source§impl<H> Default for BuildHasherDefault<H>
impl<H> Default for BuildHasherDefault<H>
source§fn default() -> BuildHasherDefault<H>
fn default() -> BuildHasherDefault<H>
Returns the “default value” for a type. Read more
1.29.0 · source§impl<H> PartialEq for BuildHasherDefault<H>
impl<H> PartialEq for BuildHasherDefault<H>
source§fn eq(&self, _other: &BuildHasherDefault<H>) -> bool
fn eq(&self, _other: &BuildHasherDefault<H>) -> bool
This method tests for
self
and other
values to be equal, and is used
by ==
.impl<H> Eq for BuildHasherDefault<H>
Auto Trait Implementations§
impl<H> RefUnwindSafe for BuildHasherDefault<H>
impl<H> Send for BuildHasherDefault<H>
impl<H> Sync for BuildHasherDefault<H>
impl<H> Unpin for BuildHasherDefault<H>
impl<H> UnwindSafe for BuildHasherDefault<H>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more