1.0.0[][src]Trait std::hash::Hash

pub trait Hash {
    fn hash<H>(&self, state: &mut H)
    where
        H: Hasher
; fn hash_slice<H>(data: &[Self], state: &mut H)
    where
        H: Hasher
, { ... } }

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

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

Provided Methods

Feeds a slice of this type into the given Hasher.

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

Implementors

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

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

impl<T> Hash for [T; 21] where
    T: Hash
[src]

impl<T> Hash for [T; 18] where
    T: Hash
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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
[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
[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
[src]

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

impl Hash for i16
[src]

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

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

impl Hash for i32
[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
    A: Hash,
    B: Hash,
    C: Hash,
    D: Hash,
    E: Hash,
    F: Hash,
    G: Hash,
    H: Hash,
    I: Hash,
    J: Hash + ?Sized
[src]

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

impl Hash for NonZeroU128
[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
[src]

impl<T> Hash for [T; 20] where
    T: Hash
[src]

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

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

impl<'a, T> Hash for &'a mut T where
    T: Hash + ?Sized
[src]

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

impl Hash for i128
[src]

impl<Ret, A> Hash for unsafe extern "C" fn(A) -> Ret
[src]

impl<Ret, A, B, C> Hash for extern "C" fn(A, B, C) -> Ret
[src]

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

impl<Ret, A> Hash for fn(A) -> Ret
[src]

impl<T> Hash for [T; 28] where
    T: Hash
[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
[src]

impl Hash for u64
[src]

impl Hash for NonZeroU64
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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
[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
[src]

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

impl<T> Hash for [T; 27] where
    T: Hash
[src]

impl<T> Hash for [T; 19] where
    T: Hash
[src]

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

impl Hash for NonZeroU16
[src]

impl Hash for u32
[src]

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

impl Hash for i64
[src]

impl<T> Hash for [T; 23] where
    T: Hash
[src]

impl Hash for bool
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impl<Ret, A, B, C, D, E, F, G> Hash for extern "C" fn(A, B, C, D, E, F, G) -> Ret
[src]

impl Hash for i8
[src]

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

impl<Ret, A> Hash for unsafe fn(A) -> Ret
[src]

impl<Ret, A, B> Hash for extern "C" fn(A, B) -> Ret
[src]

impl Hash for Duration
[src]

impl<T> Hash for [T; 26] where
    T: Hash
[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
[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
[src]

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

impl Hash for TypeId
[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
[src]

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

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

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

impl Hash for usize
[src]

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

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

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

impl<T> Hash for [T; 8] where
    T: Hash
[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
[src]

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

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

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

impl<Ret, A, B, C, D> Hash for fn(A, B, C, D) -> Ret
[src]

impl<T> Hash for [T; 25] where
    T: Hash
[src]

impl Hash for u128
[src]

impl<T> Hash for [T; 15] where
    T: Hash
[src]

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

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

impl<T> Hash for [T; 13] where
    T: Hash
[src]

impl<Ret, A, B> Hash for unsafe fn(A, B) -> Ret
[src]

impl<Ret, A, B, C, D> Hash for unsafe fn(A, B, C, D) -> Ret
[src]

impl Hash for !
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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
    A: Hash,
    B: Hash,
    C: Hash,
    D: Hash,
    E: Hash,
    F: Hash,
    G: Hash,
    H: Hash,
    I: Hash,
    J: Hash,
    K: Hash,
    L: Hash + ?Sized
[src]

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

impl Hash for NonZeroU8
[src]

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

impl<T> Hash for [T; 4] where
    T: Hash
[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
[src]

impl<Ret, A, B> Hash for fn(A, B) -> Ret
[src]

impl<Ret, A, B, C, D, E> Hash for fn(A, B, C, D, E) -> Ret
[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
[src]

impl Hash for Error
[src]

impl<T> Hash for [T; 11] where
    T: Hash
[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
[src]

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

impl<T> Hash for [T; 7] where
    T: Hash
[src]

impl Hash for char
[src]

impl Hash for NonZeroU32
[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
[src]

impl Hash for u16
[src]

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

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

impl<T> Hash for [T; 24] where
    T: Hash
[src]

impl<T> Hash for [T; 31] where
    T: Hash
[src]

impl<T> Hash for [T; 17] where
    T: Hash
[src]

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

impl Hash for u8
[src]

impl<T> Hash for [T; 9] where
    T: Hash
[src]

impl<T> Hash for [T; 10] where
    T: Hash
[src]

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

impl<Ret, A, B, C> Hash for unsafe fn(A, B, C) -> Ret
[src]

impl<T> Hash for [T; 30] where
    T: Hash
[src]

impl<T> Hash for Option<T> where
    T: Hash
[src]

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

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

impl Hash for isize
[src]

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

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

impl Hash for ()
[src]

impl Hash for NonZeroUsize
[src]

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

impl<T> Hash for [T; 3] where
    T: Hash
[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
[src]

impl<'a, T> Hash for &'a T where
    T: Hash + ?Sized
[src]

impl Hash for RangeFull
[src]

impl<Ret, A, B, C> Hash for fn(A, B, C) -> Ret
[src]

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

impl Hash for str
[src]

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

impl<T> Hash for [T; 22] where
    T: Hash
[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
[src]

impl<Ret, A> Hash for extern "C" fn(A) -> Ret
[src]

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

impl<T> Hash for [T; 2] where
    T: Hash
[src]

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

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

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

impl<T> Hash for [T; 1] where
    T: Hash
[src]

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

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

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

impl<T> Hash for [T; 12] where
    T: Hash
[src]

impl<T> Hash for [T; 29] where
    T: Hash
[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
[src]

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

impl<T> Hash for [T; 6] where
    T: Hash
[src]

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

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

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

impl Hash for Ordering
[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
[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
[src]

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

impl<T> Hash for [T; 32] where
    T: Hash
[src]

impl<T> Hash for [T; 5] where
    T: Hash
[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
[src]

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

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

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

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

impl<T> Hash for [T; 14] where
    T: Hash
[src]

impl<T> Hash for [T; 16] where
    T: Hash
[src]

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

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

impl<T> Hash for [T; 0] where
    T: Hash
[src]

impl Hash for Pinned
[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
[src]

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

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

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

impl Hash for String
[src]

impl<'a, B> Hash for Cow<'a, B> where
    B: Hash + ToOwned + ?Sized
[src]

impl<T> Hash for BTreeSet<T> where
    T: Hash
[src]

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

impl<A> Hash for VecDeque<A> where
    A: Hash
[src]

impl<T> Hash for Vec<T> where
    T: Hash
[src]

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

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

impl<T> Hash for LinkedList<T> where
    T: Hash
[src]

impl<K, V> Hash for BTreeMap<K, V> where
    K: Hash,
    V: Hash
[src]

impl Hash for ThreadId
[src]

impl Hash for CString
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impl Hash for CStr
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impl Hash for OsString
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impl Hash for OsStr
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impl Hash for FileType
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impl Hash for ErrorKind
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impl Hash for IpAddr
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impl Hash for Ipv6MulticastScope
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impl Hash for Ipv4Addr
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impl Hash for Ipv6Addr
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impl Hash for SocketAddr
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impl Hash for SocketAddrV4
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impl Hash for SocketAddrV6
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impl<'a> Hash for Prefix<'a>
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impl<'a> Hash for PrefixComponent<'a>
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impl<'a> Hash for Component<'a>
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impl Hash for PathBuf
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impl Hash for Path
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impl Hash for Instant
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impl Hash for SystemTime
[src]