Struct std::hash::BuildHasherDefault
pub struct BuildHasherDefault<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();Trait Implementations
type Hasher = H
Type of the hasher that will be created.
pub fn build_hasher(&self) -> H
Creates a new hasher. Read more
Calculates the hash of a single value. Read more
impl<H> Clone for BuildHasherDefault<H>
pub fn clone(&self) -> BuildHasherDefault<H>
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
impl<H> Debug for BuildHasherDefault<H>
pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
impl<H> PartialEq<BuildHasherDefault<H>> for BuildHasherDefault<H>
pub fn eq(&self, _other: &BuildHasherDefault<H>) -> bool
This method tests for self and other values to be equal, and is used by ==. Read more
fn ne(&self, other: &Rhs) -> bool
This method tests for !=.
impl<H> Eq for BuildHasherDefault<H>
Auto Trait Implementations
impl<H> RefUnwindSafe for BuildHasherDefault<H> where
H: RefUnwindSafe,
impl<H> Send for BuildHasherDefault<H> where
H: Send,
impl<H> Sync for BuildHasherDefault<H> where
H: Sync,
impl<H> Unpin for BuildHasherDefault<H> where
H: Unpin,
impl<H> UnwindSafe for BuildHasherDefault<H> where
H: UnwindSafe,
Blanket Implementations
impl<T> From<T> for T
pub fn from(t: T) -> T
Performs the conversion.
pub fn into(self) -> U
Performs the conversion.
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
Creates owned data from borrowed data, usually by cloning. Read more
pub fn clone_into(&self, target: &mut T)
toowned_clone_into #41263)recently added
Uses borrowed data to replace owned data, usually by cloning. Read more
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/hash/struct.BuildHasherDefault.html