enum Chunk {
    Zeros(u16),
    Ones(u16),
    Mixed(u16, u16, Rc<[u64; 32]>),
}

Variants§

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Zeros(u16)

A chunk that is all zeros; we don’t represent the zeros explicitly.

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Ones(u16)

A chunk that is all ones; we don’t represent the ones explicitly.

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Mixed(u16, u16, Rc<[u64; 32]>)

A chunk that has a mix of zeros and ones, which are represented explicitly and densely. It never has all zeros or all ones.

If this is the final chunk there may be excess, unused words. This turns out to be both simpler and have better performance than allocating the minimum number of words, largely because we avoid having to store the length, which would make this type larger. These excess words are always be zero, as are any excess bits in the final in-use word.

The second field is the count of 1s set in the chunk, and must satisfy 0 < count < chunk_domain_size.

The words are within an Rc because it’s surprisingly common to duplicate an entire chunk, e.g. in ChunkedBitSet::clone_from(), or when a Mixed chunk is union’d into a Zeros chunk. When we do need to modify a chunk we use Rc::make_mut.

Implementations§

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impl Chunk

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fn new(chunk_domain_size: usize, is_empty: bool) -> Self

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fn count(&self) -> usize

Count the number of 1s in the chunk.

Trait Implementations§

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impl Clone for Chunk

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fn clone(&self) -> Chunk

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 Chunk

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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 PartialEq for Chunk

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fn eq(&self, other: &Chunk) -> bool

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl Eq for Chunk

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impl StructuralPartialEq for Chunk

Auto Trait Implementations§

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impl Freeze for Chunk

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impl RefUnwindSafe for Chunk

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impl !Send for Chunk

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impl !Sync for Chunk

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impl Unpin for Chunk

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impl UnwindSafe for Chunk

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<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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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.

Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 16 bytes

Size for each variant:

  • Zeros: 2 bytes
  • Ones: 2 bytes
  • Mixed: 14 bytes