Trait core::hash::Hash1.0.0[][src]

pub trait Hash {
    fn hash<H: Hasher>(&self, state: &mut H);

    fn hash_slice<H: Hasher>(data: &[Self], state: &mut H)
    where
        Self: Sized
, { ... } }

A hashable type.

Types implementing Hash are able to be hashed with an instance of Hasher.

Implementing Hash

You can derive Hash with #[derive(Hash)] if all fields implement Hash. The resulting hash will be the combination of the values from calling hash on each field.

#[derive(Hash)]
struct Rustacean {
    name: String,
    country: String,
}
Run

If you need more control over how a value is hashed, you can of course implement the Hash trait yourself:

use std::hash::{Hash, Hasher};

struct Person {
    id: u32,
    name: String,
    phone: u64,
}

impl Hash for Person {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.id.hash(state);
        self.phone.hash(state);
    }
}
Run

Hash and Eq

When implementing both Hash and Eq, it is important that the following property holds:

k1 == k2 -> hash(k1) == hash(k2)

In other words, if two keys are equal, their hashes must also be equal. HashMap and HashSet both rely on this behavior.

Thankfully, you won’t need to worry about upholding this property when deriving both Eq and Hash with #[derive(PartialEq, Eq, Hash)].

Required methods

fn hash<H: Hasher>(&self, state: &mut H)[src]

Feeds this value into the given Hasher.

Examples

use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};

let mut hasher = DefaultHasher::new();
7920.hash(&mut hasher);
println!("Hash is {:x}!", hasher.finish());
Run
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Provided methods

fn hash_slice<H: Hasher>(data: &[Self], state: &mut H) where
    Self: Sized
1.3.0[src]

Feeds a slice of this type into the given Hasher.

This method is meant as a convenience, but its implementation is also explicitly left unspecified. It isn’t guaranteed to be equivalent to repeated calls of hash and implementations of Hash should keep that in mind and call hash themselves if the slice isn’t treated as a whole unit in the PartialEq implementation.

For example, a VecDeque implementation might naïvely call as_slices and then hash_slice on each slice, but this is wrong since the two slices can change with a call to make_contiguous without affecting the PartialEq result. Since these slices aren’t treated as singular units, and instead part of a larger deque, this method cannot be used.

Examples

use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};

let mut hasher = DefaultHasher::new();
let numbers = [6, 28, 496, 8128];
Hash::hash_slice(&numbers, &mut hasher);
println!("Hash is {:x}!", hasher.finish());
Run
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Implementors

impl Hash for !1.29.0[src]

impl Hash for ()[src]

impl Hash for core::cmp::Ordering[src]

impl Hash for Infallible1.44.0[src]

impl Hash for core::sync::atomic::Ordering[src]

impl Hash for TypeId[src]

impl Hash for Error[src]

impl Hash for PhantomPinned1.33.0[src]

impl Hash for NonZeroI81.34.0[src]

impl Hash for NonZeroI161.34.0[src]

impl Hash for NonZeroI321.34.0[src]

impl Hash for NonZeroI641.34.0[src]

impl Hash for NonZeroI1281.34.0[src]

impl Hash for NonZeroIsize1.34.0[src]

impl Hash for NonZeroU81.28.0[src]

impl Hash for NonZeroU161.28.0[src]

impl Hash for NonZeroU321.28.0[src]

impl Hash for NonZeroU641.28.0[src]

impl Hash for NonZeroU1281.28.0[src]

impl Hash for NonZeroUsize1.28.0[src]

impl Hash for RangeFull[src]

impl Hash for NoneError[src]

impl Hash for Duration1.3.0[src]

impl Hash for bool[src]

impl Hash for char[src]

impl Hash for i8[src]

impl Hash for i16[src]

impl Hash for i32[src]

impl Hash for i64[src]

impl Hash for i128[src]

impl Hash for isize[src]

impl Hash for str[src]

impl Hash for u8[src]

impl Hash for u16[src]

impl Hash for u32[src]

impl Hash for u64[src]

impl Hash for u128[src]

impl Hash for usize[src]

impl<'a> Hash for Location<'a>1.10.0[src]

impl<A> Hash for (A,) where
    A: Hash + ?Sized
[src]

impl<A: Hash, B> Hash for (A, B) where
    B: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C> Hash for (A, B, C) where
    C: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D> Hash for (A, B, C, D) where
    D: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D: Hash, E> Hash for (A, B, C, D, E) where
    E: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F> Hash for (A, B, C, D, E, F) where
    F: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G> Hash for (A, B, C, D, E, F, G) where
    G: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H> Hash for (A, B, C, D, E, F, G, H) where
    H: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H: Hash, I> Hash for (A, B, C, D, E, F, G, H, I) where
    I: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H: Hash, I: Hash, J> Hash for (A, B, C, D, E, F, G, H, I, J) where
    J: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H: Hash, I: Hash, J: Hash, K> Hash for (A, B, C, D, E, F, G, H, I, J, K) where
    K: Hash + ?Sized
[src]

impl<A: Hash, B: Hash, C: Hash, D: Hash, E: Hash, F: Hash, G: Hash, H: Hash, I: Hash, J: Hash, K: Hash, L> Hash for (A, B, C, D, E, F, G, H, I, J, K, L) where
    L: Hash + ?Sized
[src]

impl<Dyn: ?Sized> Hash for DynMetadata<Dyn>[src]

impl<Idx: Hash> Hash for Range<Idx>[src]

impl<Idx: Hash> Hash for RangeFrom<Idx>[src]

impl<Idx: Hash> Hash for RangeInclusive<Idx>1.26.0[src]

impl<Idx: Hash> Hash for RangeTo<Idx>[src]

impl<Idx: Hash> Hash for RangeToInclusive<Idx>1.26.0[src]

impl<P: Deref<Target: Hash>> Hash for Pin<P>1.41.0[src]

impl<Ret> Hash for extern "C" fn() -> Ret1.4.0[src]

impl<Ret> Hash for fn() -> Ret1.4.0[src]

impl<Ret> Hash for unsafe extern "C" fn() -> Ret1.4.0[src]

impl<Ret> Hash for unsafe fn() -> Ret1.4.0[src]

impl<Ret, A> Hash for extern "C" fn(_: A) -> Ret1.4.0[src]

impl<Ret, A> Hash for extern "C" fn(_: A, ...) -> Ret1.4.0[src]

impl<Ret, A> Hash for fn(_: A) -> Ret1.4.0[src]

impl<Ret, A> Hash for unsafe extern "C" fn(_: A) -> Ret1.4.0[src]

impl<Ret, A> Hash for unsafe extern "C" fn(_: A, ...) -> Ret1.4.0[src]

impl<Ret, A> Hash for unsafe fn(_: A) -> Ret1.4.0[src]

impl<Ret, A, B> Hash for extern "C" fn(_: A, _: B) -> Ret1.4.0[src]

impl<Ret, A, B> Hash for extern "C" fn(_: A, _: B, ...) -> Ret1.4.0[src]

impl<Ret, A, B> Hash for fn(_: A, _: B) -> Ret1.4.0[src]

impl<Ret, A, B> Hash for unsafe extern "C" fn(_: A, _: B) -> Ret1.4.0[src]

impl<Ret, A, B> Hash for unsafe extern "C" fn(_: A, _: B, ...) -> Ret1.4.0[src]

impl<Ret, A, B> Hash for unsafe fn(_: A, _: B) -> Ret1.4.0[src]

impl<Ret, A, B, C> Hash for extern "C" fn(_: A, _: B, _: C) -> Ret1.4.0[src]

impl<Ret, A, B, C> Hash for extern "C" fn(_: A, _: B, _: C, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C> Hash for fn(_: A, _: B, _: C) -> Ret1.4.0[src]

impl<Ret, A, B, C> Hash for unsafe extern "C" fn(_: A, _: B, _: C) -> Ret1.4.0[src]

impl<Ret, A, B, C> Hash for unsafe extern "C" fn(_: A, _: B, _: C, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C> Hash for unsafe fn(_: A, _: B, _: C) -> Ret1.4.0[src]

impl<Ret, A, B, C, D> Hash for extern "C" fn(_: A, _: B, _: C, _: D) -> Ret1.4.0[src]

impl<Ret, A, B, C, D> Hash for extern "C" fn(_: A, _: B, _: C, _: D, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D> Hash for fn(_: A, _: B, _: C, _: D) -> Ret1.4.0[src]

impl<Ret, A, B, C, D> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D) -> Ret1.4.0[src]

impl<Ret, A, B, C, D> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D> Hash for unsafe fn(_: A, _: B, _: C, _: D) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E> Hash for fn(_: A, _: B, _: C, _: D, _: E) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L, ...) -> Ret1.4.0[src]

impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Hash for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J, _: K, _: L) -> Ret1.4.0[src]

impl<T> Hash for Discriminant<T>1.21.0[src]

impl<T: Hash + ?Sized> Hash for ManuallyDrop<T>1.20.0[src]

impl<T: Hash> Hash for Bound<T>1.17.0[src]

impl<T: Hash> Hash for Option<T>[src]

impl<T: Hash> Hash for Poll<T>1.36.0[src]

impl<T: Hash> Hash for Reverse<T>1.19.0[src]

impl<T: Hash> Hash for Wrapping<T>[src]

impl<T: Hash> Hash for [T][src]

impl<T: Hash, E: Hash> Hash for Result<T, E>[src]

impl<T: Hash, const N: usize> Hash for [T; N][src]

impl<T: ?Sized + Hash> Hash for &T[src]

impl<T: ?Sized + Hash> Hash for &mut T[src]

impl<T: ?Sized> Hash for *const T[src]

impl<T: ?Sized> Hash for *mut T[src]

impl<T: ?Sized> Hash for PhantomData<T>[src]

impl<T: ?Sized> Hash for NonNull<T>1.25.0[src]

impl<Y: Hash, R: Hash> Hash for GeneratorState<Y, R>[src]

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