pub struct RandomState { /* private fields */ }
Expand description

Provides a Hasher factory. This is typically used (e.g. by HashMap) to create AHashers in order to hash the keys of the map. See build_hasher below.

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impl RandomState

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pub fn new() -> RandomState

Use randomly generated keys

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pub fn generate_with(k0: u64, k1: u64, k2: u64, k3: u64) -> RandomState

Allows for supplying seeds, but each time it is called the resulting state will be different. This is done using a static counter, so it can safely be used with a fixed keys.

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pub fn with_seed(key: usize) -> RandomState

Allows for explicitly setting a seed to used.

Note: This method does not require the provided seed to be strong.

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pub const fn with_seeds(k0: u64, k1: u64, k2: u64, k3: u64) -> RandomState

Allows for explicitly setting the seeds to used.

Note: This method is robust against 0s being passed for one or more of the parameters or the same value being passed for more than one parameter.

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pub fn hash_one<T: Hash>(&self, x: T) -> u64
where Self: Sized,

Calculates the hash of a single value.

This is intended as a convenience for code which consumes hashes, such as the implementation of a hash table or in unit tests that check whether a custom Hash implementation behaves as expected.

This must not be used in any code which creates hashes, such as in an implementation of Hash. The way to create a combined hash of multiple values is to call Hash::hash multiple times using the same Hasher, not to call this method repeatedly and combine the results.

Trait Implementations§

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impl BuildHasher for RandomState

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fn build_hasher(&self) -> AHasher

Constructs a new AHasher with keys based on this RandomState object. This means that two different RandomStates will will generate AHashers that will return different hashcodes, but Hashers created from the same BuildHasher will generate the same hashes for the same input data.

Examples
        use ahash::{AHasher, RandomState};
        use std::hash::{Hasher, BuildHasher};
    
        let build_hasher = RandomState::new();
        let mut hasher_1 = build_hasher.build_hasher();
        let mut hasher_2 = build_hasher.build_hasher();
    
        hasher_1.write_u32(1234);
        hasher_2.write_u32(1234);
    
        assert_eq!(hasher_1.finish(), hasher_2.finish());
    
        let other_build_hasher = RandomState::new();
        let mut different_hasher = other_build_hasher.build_hasher();
        different_hasher.write_u32(1234);
        assert_ne!(different_hasher.finish(), hasher_1.finish());
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fn hash_one<T: Hash>(&self, x: T) -> u64

Calculates the hash of a single value.

This is intended as a convenience for code which consumes hashes, such as the implementation of a hash table or in unit tests that check whether a custom Hash implementation behaves as expected.

This must not be used in any code which creates hashes, such as in an implementation of Hash. The way to create a combined hash of multiple values is to call Hash::hash multiple times using the same Hasher, not to call this method repeatedly and combine the results.

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type Hasher = AHasher

Type of the hasher that will be created.
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impl Clone for RandomState

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fn clone(&self) -> RandomState

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for RandomState

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Default for RandomState

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fn default() -> Self

Returns the “default value” for a type. Read more

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.