1.7.0[][src]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();Run

Trait Implementations

impl<H> Default for BuildHasherDefault<H>
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Returns the "default value" for a type. Read more

impl<H> BuildHasher for BuildHasherDefault<H> where
    H: Default + Hasher
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Type of the hasher that will be created.

Creates a new hasher. Read more

impl<H> Clone for BuildHasherDefault<H>
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Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

impl<H> Eq for BuildHasherDefault<H>
1.29.0
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impl<H> Debug for BuildHasherDefault<H>
1.9.0
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Formats the value using the given formatter. Read more

impl<H> PartialEq<BuildHasherDefault<H>> for BuildHasherDefault<H>
1.29.0
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This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Auto Trait Implementations

impl<H> Send for BuildHasherDefault<H> where
    H: Send

impl<H> Sync for BuildHasherDefault<H> where
    H: Sync

Blanket Implementations

impl<T, U> TryFrom for T where
    T: From<U>, 
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🔬 This is a nightly-only experimental API. (try_from #33417)

The type returned in the event of a conversion error.

🔬 This is a nightly-only experimental API. (try_from #33417)

Performs the conversion.

impl<T> From for T
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Performs the conversion.

impl<T, U> TryInto for T where
    U: TryFrom<T>, 
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🔬 This is a nightly-only experimental API. (try_from #33417)

The type returned in the event of a conversion error.

🔬 This is a nightly-only experimental API. (try_from #33417)

Performs the conversion.

impl<T, U> Into for T where
    U: From<T>, 
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Performs the conversion.

impl<T> Borrow for T where
    T: ?Sized
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Important traits for &'_ mut I

Immutably borrows from an owned value. Read more

impl<T> BorrowMut for T where
    T: ?Sized
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Important traits for &'_ mut I

Mutably borrows from an owned value. Read more

impl<T> Any for T where
    T: 'static + ?Sized
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🔬 This is a nightly-only experimental API. (get_type_id #27745)

this method will likely be replaced by an associated static

Gets the TypeId of self. Read more

impl<T> ToOwned for T where
    T: Clone
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Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more