Struct BuildHasherDefault

pub struct BuildHasherDefault<H>(pub(in ::hash) PhantomData<fn() -> 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();

Fields

0: PhantomData<fn() -> H>

Implementations

impl<H> BuildHasherDefault<H>

const fn new() -> Self

Creates a new BuildHasherDefault for Hasher H.

Trait Implementations

impl<H> Clone for BuildHasherDefault<H>

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

impl<H> Debug for BuildHasherDefault<H>

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

impl<H> Default for BuildHasherDefault<H>

fn default() -> BuildHasherDefault<H>

impl<H> Eq for BuildHasherDefault<H>

impl<H> PartialEq for BuildHasherDefault<H>

fn eq(&self, _other: &BuildHasherDefault<H>) -> bool

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

type Hasher = H;
fn build_hasher(&self) -> H

Auto Trait Implementations

impl<H> Freeze for BuildHasherDefault<H> where PhantomData<fn() -> H>: Freeze,

impl<H> RefUnwindSafe for BuildHasherDefault<H> where PhantomData<fn() -> H>: RefUnwindSafe,

impl<H> Send for BuildHasherDefault<H> where PhantomData<fn() -> H>: Send,

impl<H> Sync for BuildHasherDefault<H> where PhantomData<fn() -> H>: Sync,

impl<H> Unpin for BuildHasherDefault<H> where PhantomData<fn() -> H>: Unpin,

impl<H> UnsafeUnpin for BuildHasherDefault<H> where PhantomData<fn() -> H>: UnsafeUnpin,

impl<H> UnwindSafe for BuildHasherDefault<H> where PhantomData<fn() -> H>: UnwindSafe,

Blanket Implementations

impl<T> Any for BuildHasherDefault<H> where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for BuildHasherDefault<H> where T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for BuildHasherDefault<H> where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> CloneToUninit for BuildHasherDefault<H> where T: Clone,

unsafe fn clone_to_uninit(&self, dest: *mut u8)

impl<T> From<T> for BuildHasherDefault<H>

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> SizeHint for BuildHasherDefault<H> where T: ?Sized,

fn lower_bound(&self) -> usize
fn upper_bound(&self) -> Option<usize>

impl<T> SizedTypeProperties for BuildHasherDefault<H>

impl<T, U> Into<U> for BuildHasherDefault<H> where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

impl<T, U> TryFrom<U> for BuildHasherDefault<H> where U: Into<T>,

type Error = Infallible;
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto<U> for BuildHasherDefault<H> where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error;
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>