Expand description
A hashable type.
Types implementing Hash are able to be hashed with an instance of
Hasher.
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
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)].
Feeds this value into the given Hasher.
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
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.
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
This is supported on Unix only.
impl<A, B, C, D> Hash for (A, B, C, D) where
C: Hash,
B: Hash,
A: Hash,
D: Hash + ?Sized,
[src]
impl<A, B, C, D, E> Hash for (A, B, C, D, E) where
C: Hash,
E: Hash + ?Sized,
B: Hash,
A: Hash,
D: Hash,
[src]
impl<A, B, C, D, E, F> Hash for (A, B, C, D, E, F) where
C: Hash,
F: Hash + ?Sized,
E: Hash,
B: Hash,
A: Hash,
D: Hash,
[src]
impl<A, B, C, D, E, F, G> Hash for (A, B, C, D, E, F, G) where
C: Hash,
F: Hash,
E: Hash,
B: Hash,
A: Hash,
G: Hash + ?Sized,
D: Hash,
[src]
impl<A, B, C, D, E, F, G, H> Hash for (A, B, C, D, E, F, G, H) where
C: Hash,
F: Hash,
E: Hash,
H: Hash + ?Sized,
B: Hash,
A: Hash,
G: Hash,
D: Hash,
[src]
impl<A, B, C, D, E, F, G, H, I> Hash for (A, B, C, D, E, F, G, H, I) where
C: Hash,
F: Hash,
I: Hash + ?Sized,
E: Hash,
H: Hash,
B: Hash,
A: Hash,
G: Hash,
D: Hash,
[src]
impl<A, B, C, D, E, F, G, H, I, J> Hash for (A, B, C, D, E, F, G, H, I, J) where
C: Hash,
F: Hash,
I: Hash,
E: Hash,
H: Hash,
B: Hash,
A: Hash,
J: Hash + ?Sized,
G: Hash,
D: Hash,
[src]
impl<A, B, C, D, E, F, G, H, I, J, K> Hash for (A, B, C, D, E, F, G, H, I, J, K) where
C: Hash,
F: Hash,
K: Hash + ?Sized,
I: Hash,
E: Hash,
H: Hash,
B: Hash,
A: Hash,
J: Hash,
G: Hash,
D: Hash,
[src]
impl<A, B, C, D, E, F, G, H, I, J, K, L> Hash for (A, B, C, D, E, F, G, H, I, J, K, L) where
C: Hash,
F: Hash,
K: Hash,
I: Hash,
E: Hash,
H: Hash,
B: Hash,
A: Hash,
J: Hash,
G: Hash,
D: Hash,
L: Hash + ?Sized,
[src]
impl<Ret> Hash for unsafe extern "C" fn() -> Ret
1.4.0[src]
impl<Ret, A> Hash for extern "C" fn(A) -> Ret
1.4.0[src]
impl<Ret, A> Hash for extern "C" fn(A, ...) -> Ret
1.4.0[src]
impl<Ret, A> Hash for unsafe extern "C" fn(A) -> Ret
1.4.0[src]
impl<Ret, A> Hash for unsafe extern "C" fn(A, ...) -> Ret
1.4.0[src]
impl<Ret, A, B> Hash for extern "C" fn(A, B) -> Ret
1.4.0[src]
impl<Ret, A, B> Hash for extern "C" fn(A, B, ...) -> Ret
1.4.0[src]
impl<Ret, A, B> Hash for unsafe fn(A, B) -> Ret
1.4.0[src]
impl<Ret, A, B> Hash for unsafe extern "C" fn(A, B) -> Ret
1.4.0[src]
impl<Ret, A, B> Hash for unsafe extern "C" fn(A, B, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C> Hash for fn(A, B, C) -> Ret
1.4.0[src]
impl<Ret, A, B, C> Hash for extern "C" fn(A, B, C) -> Ret
1.4.0[src]
impl<Ret, A, B, C> Hash for extern "C" fn(A, B, C, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C> Hash for unsafe fn(A, B, C) -> Ret
1.4.0[src]
impl<Ret, A, B, C> Hash for unsafe extern "C" fn(A, B, C) -> Ret
1.4.0[src]
impl<Ret, A, B, C> Hash for unsafe extern "C" fn(A, B, C, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D> Hash for fn(A, B, C, D) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D> Hash for extern "C" fn(A, B, C, D) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D> Hash for extern "C" fn(A, B, C, D, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D> Hash for unsafe fn(A, B, C, D) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D> Hash for unsafe extern "C" fn(A, B, C, D) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D> Hash for unsafe extern "C" fn(A, B, C, D, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E> Hash for fn(A, B, C, D, E) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E> Hash for extern "C" fn(A, B, C, D, E) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E> Hash for extern "C" fn(A, B, C, D, E, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E> Hash for unsafe fn(A, B, C, D, E) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E> Hash for unsafe extern "C" fn(A, B, C, D, E) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E> Hash for unsafe extern "C" fn(A, B, C, D, E, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F> Hash for fn(A, B, C, D, E, F) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F> Hash for extern "C" fn(A, B, C, D, E, F) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F> Hash for extern "C" fn(A, B, C, D, E, F, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F> Hash for unsafe fn(A, B, C, D, E, F) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F> Hash for unsafe extern "C" fn(A, B, C, D, E, F) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F> Hash for unsafe extern "C" fn(A, B, C, D, E, F, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G> Hash for fn(A, B, C, D, E, F, G) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(A, B, C, D, E, F, G) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(A, B, C, D, E, F, G, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G> Hash for unsafe fn(A, B, C, D, E, F, G) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G> Hash for unsafe extern "C" fn(A, B, C, D, E, F, G, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G, H> Hash for fn(A, B, C, D, E, F, G, H) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G, H> Hash for extern "C" fn(A, B, C, D, E, F, G, H) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G, H> Hash for extern "C" fn(A, B, C, D, E, F, G, H, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G, H> Hash for unsafe fn(A, B, C, D, E, F, G, H) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[src]
impl<Ret, A, B, C, D, E, F, G, H, I> Hash for fn(A, B, C, D, E, F, G, H, I) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[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) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[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) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[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) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[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) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[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) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[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) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[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) -> Ret
1.4.0[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) -> Ret
1.4.0[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, ...) -> Ret
1.4.0[src]