#[repr(transparent)]
pub struct BitArray<A = [usize; 1], O = Lsb0> where
    A: BitViewSized,
    O: BitOrder
{ pub _ord: PhantomData<O>, pub data: A, }
Expand description

Bit-Precision Array Immediate

This type is a wrapper over the array fundamental [T; N] that views its contents as a BitSlice region. As an array, it can be held directly by value and does not require an indirection such as the &BitSlice reference.

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[T; N]

Usage

BitArray is a Rust analogue of the C++ std::bitset<N> container. However, restrictions in the Rust type system do not allow specifying exact bit lengths in the array type. Instead, it must specify a storage array that can contain all the bits you want.

Because BitArray is a plain-old-data object, its fields are public and it has no restrictions on its interior value. You can freely access the interior storage and move data in or out of the BitArray type with no cost.

As a convenience, the BitArr! type-constructor macro can produce correct type definitions from an exact bit count and your memory-layout type parameters. Values of that type can then be built from the bitarr! value-constructor macro:

use bitvec::prelude::*;

type Example = BitArr!(for 43, in u32, Msb0);
let example: Example = bitarr!(u32, Msb0; 1; 33);

struct HasBitfield {
  inner: Example,
}

let ex2 = HasBitfield {
  inner: BitArray::new([1, 2]),
};

Note that the actual type of the Example alias is BitArray<[u32; 2], Msb0>, as that is ceil(32, 43), so the bitarr! macro can accept any number of bits in 33 .. 65 and will produce a value of the correct type.

Type Parameters

BitArray differs from the other data structures in the crate in that it does not take a T: BitStore parameter, but rather takes A: BitViewSized. That trait is implemented by all T: BitStore scalars and all [T; N] arrays of them, and provides the logic to translate the aggregate storage into the memory sequence that the crate expects.

As with all BitSlice regions, the O: BitOrder parameter specifies the ordering of bits within a single A::Store element.

Future API Changes

Exact bit lengths cannot be encoded into the BitArray type until the const-generics system in the compiler can allow type-level computation on type integers. When this stabilizes, bitvec will issue a major upgrade that replaces the BitArray<A, O> definition with BitArray<T, O, const N: usize> and match the C++ std::bitset<N> definition.

Large Bit-Arrays

As with ordinary arrays, large arrays can be expensive to move by value, and should generally be preferred to have static locations such as actual static bindings, a long lifetime in a low stack frame, or a heap allocation. While you certainly can Box<[BitArray<A, O>]> directly, you may instead prefer the BitBox or BitVec heap-allocated regions. These offer the same storage behavior and are better optimized than Box<BitArray> for working with the contained BitSlice region.

Examples

use bitvec::prelude::*;

const WELL_KNOWN: BitArr!(for 16, in u8, Lsb0) = BitArray::<[u8; 2], Lsb0> {
  data: *b"bv",
  ..BitArray::ZERO
};

struct HasBitfields {
  inner: BitArr!(for 50, in u8, Lsb0),
}

impl HasBitfields {
  fn new() -> Self {
    Self {
      inner: bitarr!(u8, Lsb0; 0; 50),
    }
  }

  fn some_field(&self) -> &BitSlice<u8, Lsb0> {
    &self.inner[2 .. 52]
  }
}

Fields

_ord: PhantomData<O>

The ordering of bits within an A::Store element.

data: A

The wrapped data buffer.

Implementations

👎 Deprecated:

use .as_bitslice() or .as_raw_slice() instead

Returns a bit-slice containing the entire bit-array. Equivalent to &a[..].

Because BitArray can be viewed as a slice of bits or as a slice of elements with equal ease, you should switch to using .as_bitslice() or .as_raw_slice() to make your choice explicit.

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array::as_slice

👎 Deprecated:

use .as_mut_bitslice() or .as_raw_mut_slice() instead

Returns a mutable bit-slice containing the entire bit-array. Equivalent to &mut a[..].

Because BitArray can be viewed as a slice of bits or as a slice of elements with equal ease, you should switch to using .as_mut_bitslice() or .as_raw_mut_slice() to make your choice explicit.

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array::as_mut_slice

A bit-array with all bits initialized to zero.

Wraps an existing buffer as a bit-array.

Examples
use bitvec::prelude::*;

let data = [0u16, 1, 2, 3];
let bits = BitArray::<_, Msb0>::new(data);
assert_eq!(bits.len(), 64);

Removes the bit-array wrapper, returning the contained buffer.

Examples
use bitvec::prelude::*;

let bits = bitarr![0; 30];
let native: [usize; 1] = bits.into_inner();

Explicitly views the bit-array as a bit-slice.

Explicitly views the bit-array as a mutable bit-slice.

Views the bit-array as a slice of its underlying memory elements.

Views the bit-array as a mutable slice of its underlying memory elements.

Gets the length (in bits) of the bit-array.

This method is a compile-time constant.

Tests whether the array is empty.

This method is a compile-time constant.

Methods from Deref<Target = BitSlice<A::Store, O>>

Gets the number of bits in the bit-slice.

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slice::len

Examples
use bitvec::prelude::*;

assert_eq!(bits![].len(), 0);
assert_eq!(bits![0; 10].len(), 10);

Tests if the bit-slice is empty (length zero).

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slice::is_empty

Examples
use bitvec::prelude::*;

assert!(bits![].is_empty());
assert!(!bits![0; 10].is_empty());

Gets a reference to the first bit of the bit-slice, or None if it is empty.

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slice::first

API Differences

bitvec uses a custom structure for both read-only and mutable references to bool.

Examples
use bitvec::prelude::*;

let bits = bits![1, 0, 0];
assert_eq!(bits.first().as_deref(), Some(&true));

assert!(bits![].first().is_none());

Gets a mutable reference to the first bit of the bit-slice, or None if it is empty.

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slice::first_mut

API Differences

bitvec uses a custom structure for both read-only and mutable references to bool. This must be bound as mut in order to write through it.

Examples
use bitvec::prelude::*;

let bits = bits![mut 0; 3];
if let Some(mut first) = bits.first_mut() {
  *first = true;
}
assert_eq!(bits, bits![1, 0, 0]);

assert!(bits![mut].first_mut().is_none());

Splits the bit-slice into a reference to its first bit, and the rest of the bit-slice. Returns None when empty.

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slice::split_first

API Differences

bitvec uses a custom structure for both read-only and mutable references to bool.

Examples
use bitvec::prelude::*;

let bits = bits![1, 0, 0];
let (first, rest) = bits.split_first().unwrap();
assert_eq!(first, &true);
assert_eq!(rest, bits![0; 2]);

Splits the bit-slice into mutable references of its first bit, and the rest of the bit-slice. Returns None when empty.

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slice::split_first_mut

API Differences

bitvec uses a custom structure for both read-only and mutable references to bool. This must be bound as mut in order to write through it.

Examples
use bitvec::prelude::*;

let bits = bits![mut 0; 3];
if let Some((mut first, rest)) = bits.split_first_mut() {
  *first = true;
  assert_eq!(rest, bits![0; 2]);
}
assert_eq!(bits, bits![1, 0, 0]);

Splits the bit-slice into a reference to its last bit, and the rest of the bit-slice. Returns None when empty.

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slice::split_last

API Differences

bitvec uses a custom structure for both read-only and mutable references to bool.

Examples
use bitvec::prelude::*;

let bits = bits![0, 0, 1];
let (last, rest) = bits.split_last().unwrap();
assert_eq!(last, &true);
assert_eq!(rest, bits![0; 2]);

Splits the bit-slice into mutable references to its last bit, and the rest of the bit-slice. Returns None when empty.

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slice::split_last_mut

API Differences

bitvec uses a custom structure for both read-only and mutable references to bool. This must be bound as mut in order to write through it.

Examples
use bitvec::prelude::*;

let bits = bits![mut 0; 3];
if let Some((mut last, rest)) = bits.split_last_mut() {
  *last = true;
  assert_eq!(rest, bits![0; 2]);
}
assert_eq!(bits, bits![0, 0, 1]);

Gets a reference to the last bit of the bit-slice, or None if it is empty.

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slice::last

API Differences

bitvec uses a custom structure for both read-only and mutable references to bool.

Examples
use bitvec::prelude::*;

let bits = bits![0, 0, 1];
assert_eq!(bits.last().as_deref(), Some(&true));

assert!(bits![].last().is_none());

Gets a mutable reference to the last bit of the bit-slice, or None if it is empty.

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slice::last_mut

API Differences

bitvec uses a custom structure for both read-only and mutable references to bool. This must be bound as mut in order to write through it.

Examples
use bitvec::prelude::*;

let bits = bits![mut 0; 3];
if let Some(mut last) = bits.last_mut() {
  *last = true;
}
assert_eq!(bits, bits![0, 0, 1]);

assert!(bits![mut].last_mut().is_none());

Gets a reference to a single bit or a subsection of the bit-slice, depending on the type of index.

  • If given a usize, this produces a reference structure to the bool at the position.
  • If given any form of range, this produces a smaller bit-slice.

This returns None if the index departs the bounds of self.

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slice::get

API Differences

BitSliceIndex uses discrete types for immutable and mutable references, rather than a single referent type.

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0];
assert_eq!(bits.get(1).as_deref(), Some(&true));
assert_eq!(bits.get(0 .. 2), Some(bits![0, 1]));
assert!(bits.get(3).is_none());
assert!(bits.get(0 .. 4).is_none());

Gets a mutable reference to a single bit or a subsection of the bit-slice, depending on the type of index.

  • If given a usize, this produces a reference structure to the bool at the position.
  • If given any form of range, this produces a smaller bit-slice.

This returns None if the index departs the bounds of self.

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slice::get_mut

API Differences

BitSliceIndex uses discrete types for immutable and mutable references, rather than a single referent type.

Examples
use bitvec::prelude::*;

let bits = bits![mut 0; 3];

*bits.get_mut(0).unwrap() = true;
bits.get_mut(1 ..).unwrap().fill(true);
assert_eq!(bits, bits![1; 3]);

Gets a reference to a single bit or to a subsection of the bit-slice, without bounds checking.

This has the same arguments and behavior as .get(), except that it does not check that index is in bounds.

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slice::get_unchecked

Safety

You must ensure that index is within bounds (within the range 0 .. self.len()), or this method will introduce memory safety and/or undefined behavior.

It is library-level undefined behavior to index beyond the length of any bit-slice, even if you know that the offset remains within an allocation as measured by Rust or LLVM.

Examples
use bitvec::prelude::*;

let data = 0b0001_0010u8;
let bits = &data.view_bits::<Lsb0>()[.. 3];

unsafe {
  assert!(bits.get_unchecked(1));
  assert!(bits.get_unchecked(4));
}

Gets a mutable reference to a single bit or a subsection of the bit-slice, depending on the type of index.

This has the same arguments and behavior as .get_mut(), except that it does not check that index is in bounds.

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slice::get_unchecked_mut

Safety

You must ensure that index is within bounds (within the range 0 .. self.len()), or this method will introduce memory safety and/or undefined behavior.

It is library-level undefined behavior to index beyond the length of any bit-slice, even if you know that the offset remains within an allocation as measured by Rust or LLVM.

Examples
use bitvec::prelude::*;

let mut data = 0u8;
let bits = &mut data.view_bits_mut::<Lsb0>()[.. 3];

unsafe {
  bits.get_unchecked_mut(1).commit(true);
  bits.get_unchecked_mut(4 .. 6).fill(true);
}
assert_eq!(data, 0b0011_0010);
👎 Deprecated:

use .as_bitptr() instead

👎 Deprecated:

use .as_mut_bitptr() instead

Produces a range of bit-pointers to each bit in the bit-slice.

This is a standard-library range, which has no real functionality for pointer types. You should prefer .as_bitptr_range() instead, as it produces a custom structure that provides expected ranging functionality.

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slice::as_ptr_range

Produces a range of mutable bit-pointers to each bit in the bit-slice.

This is a standard-library range, which has no real functionality for pointer types. You should prefer .as_mut_bitptr_range() instead, as it produces a custom structure that provides expected ranging functionality.

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slice::as_mut_ptr_range

Exchanges the bit values at two indices.

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slice::swap

Panics

This panics if either a or b are out of bounds.

Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 1];
bits.swap(0, 1);
assert_eq!(bits, bits![1, 0]);

Reverses the order of bits in a bit-slice.

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slice::reverse

Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0, 1, 0, 1, 1, 0, 0, 1];
bits.reverse();
assert_eq!(bits, bits![1, 0, 0, 1, 1, 0, 1, 0, 0]);

Produces an iterator over each bit in the bit-slice.

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slice::iter

API Differences

This iterator yields proxy-reference structures, not &bool. It can be adapted to yield &bool with the .by_refs() method, or bool with .by_vals().

This iterator, and its adapters, are fast. Do not try to be more clever than them by abusing .as_bitptr_range().

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 1];
let mut iter = bits.iter();

assert!(!iter.next().unwrap());
assert!( iter.next().unwrap());
assert!( iter.next_back().unwrap());
assert!(!iter.next_back().unwrap());
assert!( iter.next().is_none());

Produces a mutable iterator over each bit in the bit-slice.

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slice::iter_mut

API Differences

This iterator yields proxy-reference structures, not &mut bool. In addition, it marks each proxy as alias-tainted.

If you are using this in an ordinary loop and not keeping multiple yielded proxy-references alive at the same scope, you may use the .remove_alias() adapter to undo the alias marking.

This iterator is fast. Do not try to be more clever than it by abusing .as_mut_bitptr_range().

Examples
use bitvec::prelude::*;

let bits = bits![mut 0; 4];
let mut iter = bits.iter_mut();

iter.nth(1).unwrap().commit(true); // index 1
iter.next_back().unwrap().commit(true); // index 3

assert!(iter.next().is_some()); // index 2
assert!(iter.next().is_none()); // complete
assert_eq!(bits, bits![0, 1, 0, 1]);

Iterates over consecutive windowing subslices in a bit-slice.

Windows are overlapping views of the bit-slice. Each window advances one bit from the previous, so in a bit-slice [A, B, C, D, E], calling .windows(3) will yield [A, B, C], [B, C, D], and [C, D, E].

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slice::windows

Panics

This panics if size is 0.

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 0, 1];
let mut iter = bits.windows(3);

assert_eq!(iter.next(), Some(bits![0, 1, 0]));
assert_eq!(iter.next(), Some(bits![1, 0, 0]));
assert_eq!(iter.next(), Some(bits![0, 0, 1]));
assert!(iter.next().is_none());

Iterates over non-overlapping subslices of a bit-slice.

Unlike .windows(), the subslices this yields do not overlap with each other. If self.len() is not an even multiple of chunk_size, then the last chunk yielded will be shorter.

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slice::chunks

Sibling Methods
  • .chunks_mut() has the same division logic, but each yielded bit-slice is mutable.
  • .chunks_exact() does not yield the final chunk if it is shorter than chunk_size.
  • .rchunks() iterates from the back of the bit-slice to the front, with the final, possibly-shorter, segment at the front edge.
Panics

This panics if chunk_size is 0.

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 0, 1];
let mut iter = bits.chunks(2);

assert_eq!(iter.next(), Some(bits![0, 1]));
assert_eq!(iter.next(), Some(bits![0, 0]));
assert_eq!(iter.next(), Some(bits![1]));
assert!(iter.next().is_none());

Iterates over non-overlapping mutable subslices of a bit-slice.

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded subslices for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

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slice::chunks_mut

Sibling Methods
  • .chunks() has the same division logic, but each yielded bit-slice is immutable.
  • .chunks_exact_mut() does not yield the final chunk if it is shorter than chunk_size.
  • .rchunks_mut() iterates from the back of the bit-slice to the front, with the final, possibly-shorter, segment at the front edge.
Panics

This panics if chunk_size is 0.

Examples
use bitvec::prelude::*;

let bits = bits![mut u8, Msb0; 0; 5];

for (idx, chunk) in unsafe {
  bits.chunks_mut(2).remove_alias()
}.enumerate() {
  chunk.store(idx + 1);
}
assert_eq!(bits, bits![0, 1, 1, 0, 1]);
//                     ^^^^  ^^^^  ^

Iterates over non-overlapping subslices of a bit-slice.

If self.len() is not an even multiple of chunk_size, then the last few bits are not yielded by the iterator at all. They can be accessed with the .remainder() method if the iterator is bound to a name.

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slice::chunks_exact

Sibling Methods
  • .chunks() yields any leftover bits at the end as a shorter chunk during iteration.
  • .chunks_exact_mut() has the same division logic, but each yielded bit-slice is mutable.
  • .rchunks_exact() iterates from the back of the bit-slice to the front, with the unyielded remainder segment at the front edge.
Panics

This panics if chunk_size is 0.

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 0, 1];
let mut iter = bits.chunks_exact(2);

assert_eq!(iter.next(), Some(bits![0, 1]));
assert_eq!(iter.next(), Some(bits![0, 0]));
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), bits![1]);

Iterates over non-overlapping mutable subslices of a bit-slice.

If self.len() is not an even multiple of chunk_size, then the last few bits are not yielded by the iterator at all. They can be accessed with the .into_remainder() method if the iterator is bound to a name.

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded subslices for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

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slice::chunks_exact_mut

Sibling Methods
  • .chunks_mut() yields any leftover bits at the end as a shorter chunk during iteration.
  • .chunks_exact() has the same division logic, but each yielded bit-slice is immutable.
  • .rchunks_exact_mut() iterates from the back of the bit-slice forwards, with the unyielded remainder segment at the front edge.
Panics

This panics if chunk_size is 0.

Examples
use bitvec::prelude::*;

let bits = bits![mut u8, Msb0; 0; 5];
let mut iter = bits.chunks_exact_mut(2);

for (idx, chunk) in iter.by_ref().enumerate() {
  chunk.store(idx + 1);
}
iter.into_remainder().store(1u8);

assert_eq!(bits, bits![0, 1, 1, 0, 1]);
//                       remainder ^

Iterates over non-overlapping subslices of a bit-slice, from the back edge.

Unlike .chunks(), this aligns its chunks to the back edge of self. If self.len() is not an even multiple of chunk_size, then the leftover partial chunk is self[0 .. len % chunk_size].

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slice::rchunks

Sibling Methods
  • .rchunks_mut() has the same division logic, but each yielded bit-slice is mutable.
  • .rchunks_exact() does not yield the final chunk if it is shorter than chunk_size.
  • .chunks() iterates from the front of the bit-slice to the back, with the final, possibly-shorter, segment at the back edge.
Panics

This panics if chunk_size is 0.

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 0, 1];
let mut iter = bits.rchunks(2);

assert_eq!(iter.next(), Some(bits![0, 1]));
assert_eq!(iter.next(), Some(bits![1, 0]));
assert_eq!(iter.next(), Some(bits![0]));
assert!(iter.next().is_none());

Iterates over non-overlapping mutable subslices of a bit-slice, from the back edge.

Unlike .chunks_mut(), this aligns its chunks to the back edge of self. If self.len() is not an even multiple of chunk_size, then the leftover partial chunk is self[0 .. len % chunk_size].

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded values for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

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slice::rchunks_mut

Sibling Methods
  • .rchunks() has the same division logic, but each yielded bit-slice is immutable.
  • .rchunks_exact_mut() does not yield the final chunk if it is shorter than chunk_size.
  • .chunks_mut() iterates from the front of the bit-slice to the back, with the final, possibly-shorter, segment at the back edge.
Examples
use bitvec::prelude::*;

let bits = bits![mut u8, Msb0; 0; 5];
for (idx, chunk) in unsafe {
  bits.rchunks_mut(2).remove_alias()
}.enumerate() {
  chunk.store(idx + 1);
}
assert_eq!(bits, bits![1, 1, 0, 0, 1]);
//           remainder ^  ^^^^  ^^^^

Iterates over non-overlapping subslices of a bit-slice, from the back edge.

If self.len() is not an even multiple of chunk_size, then the first few bits are not yielded by the iterator at all. They can be accessed with the .remainder() method if the iterator is bound to a name.

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slice::rchunks_exact

Sibling Methods
  • .rchunks() yields any leftover bits at the front as a shorter chunk during iteration.
  • .rchunks_exact_mut() has the same division logic, but each yielded bit-slice is mutable.
  • .chunks_exact() iterates from the front of the bit-slice to the back, with the unyielded remainder segment at the back edge.
Panics

This panics if chunk_size is 0.

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 0, 1];
let mut iter = bits.rchunks_exact(2);

assert_eq!(iter.next(), Some(bits![0, 1]));
assert_eq!(iter.next(), Some(bits![1, 0]));
assert!(iter.next().is_none());
assert_eq!(iter.remainder(), bits![0]);

Iterates over non-overlapping mutable subslices of a bit-slice, from the back edge.

If self.len() is not an even multiple of chunk_size, then the first few bits are not yielded by the iterator at all. They can be accessed with the .into_remainder() method if the iterator is bound to a name.

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded subslices for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

Sibling Methods
  • .rchunks_mut() yields any leftover bits at the front as a shorter chunk during iteration.
  • .rchunks_exact() has the same division logic, but each yielded bit-slice is immutable.
  • .chunks_exact_mut() iterates from the front of the bit-slice backwards, with the unyielded remainder segment at the back edge.
Panics

This panics if chunk_size is 0.

Examples
use bitvec::prelude::*;

let bits = bits![mut u8, Msb0; 0; 5];
let mut iter = bits.rchunks_exact_mut(2);

for (idx, chunk) in iter.by_ref().enumerate() {
  chunk.store(idx + 1);
}
iter.into_remainder().store(1u8);

assert_eq!(bits, bits![1, 1, 0, 0, 1]);
//           remainder ^

Splits a bit-slice in two parts at an index.

The returned bit-slices are self[.. mid] and self[mid ..]. mid is included in the right bit-slice, not the left.

If mid is 0 then the left bit-slice is empty; if it is self.len() then the right bit-slice is empty.

This method guarantees that even when either partition is empty, the encoded bit-pointer values of the bit-slice references is &self[0] and &self[mid].

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slice::split_at

Panics

This panics if mid is greater than self.len(). It is allowed to be equal to the length, in which case the right bit-slice is simply empty.

Examples
use bitvec::prelude::*;

let bits = bits![0, 0, 0, 1, 1, 1];
let base = bits.as_bitptr();

let (a, b) = bits.split_at(0);
assert_eq!(unsafe { a.as_bitptr().offset_from(base) }, 0);
assert_eq!(unsafe { b.as_bitptr().offset_from(base) }, 0);

let (a, b) = bits.split_at(6);
assert_eq!(unsafe { b.as_bitptr().offset_from(base) }, 6);

let (a, b) = bits.split_at(3);
assert_eq!(a, bits![0; 3]);
assert_eq!(b, bits![1; 3]);

Splits a mutable bit-slice in two parts at an index.

The returned bit-slices are self[.. mid] and self[mid ..]. mid is included in the right bit-slice, not the left.

If mid is 0 then the left bit-slice is empty; if it is self.len() then the right bit-slice is empty.

This method guarantees that even when either partition is empty, the encoded bit-pointer values of the bit-slice references is &self[0] and &self[mid].

Original

slice::split_at_mut

API Differences

The end bits of the left half and the start bits of the right half might be stored in the same memory element. In order to avoid breaking bitvec’s memory-safety guarantees, both bit-slices are marked as T::Alias. This marking allows them to be used without interfering with each other when they interact with memory.

Panics

This panics if mid is greater than self.len(). It is allowed to be equal to the length, in which case the right bit-slice is simply empty.

Examples
use bitvec::prelude::*;

let bits = bits![mut u8, Msb0; 0; 6];
let base = bits.as_mut_bitptr();

let (a, b) = bits.split_at_mut(0);
assert_eq!(unsafe { a.as_mut_bitptr().offset_from(base) }, 0);
assert_eq!(unsafe { b.as_mut_bitptr().offset_from(base) }, 0);

let (a, b) = bits.split_at_mut(6);
assert_eq!(unsafe { b.as_mut_bitptr().offset_from(base) }, 6);

let (a, b) = bits.split_at_mut(3);
a.store(3);
b.store(5);

assert_eq!(bits, bits![0, 1, 1, 1, 0, 1]);

Iterates over subslices separated by bits that match a predicate. The matched bit is not contained in the yielded bit-slices.

Original

slice::split

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .split_mut() has the same splitting logic, but each yielded bit-slice is mutable.
  • .split_inclusive() includes the matched bit in the yielded bit-slice.
  • .rsplit() iterates from the back of the bit-slice instead of the front.
  • .splitn() times out after n yields.
Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 1, 0];
//                     ^
let mut iter = bits.split(|pos, _bit| pos % 3 == 2);

assert_eq!(iter.next().unwrap(), bits![0, 1]);
assert_eq!(iter.next().unwrap(), bits![0]);
assert!(iter.next().is_none());

If the first bit is matched, then an empty bit-slice will be the first item yielded by the iterator. Similarly, if the last bit in the bit-slice matches, then an empty bit-slice will be the last item yielded.

use bitvec::prelude::*;

let bits = bits![0, 0, 1];
//                     ^
let mut iter = bits.split(|_pos, bit| *bit);

assert_eq!(iter.next().unwrap(), bits![0; 2]);
assert!(iter.next().unwrap().is_empty());
assert!(iter.next().is_none());

If two matched bits are directly adjacent, then an empty bit-slice will be yielded between them:

use bitvec::prelude::*;

let bits = bits![1, 0, 0, 1];
//                  ^  ^
let mut iter = bits.split(|_pos, bit| !*bit);

assert_eq!(iter.next().unwrap(), bits![1]);
assert!(iter.next().unwrap().is_empty());
assert_eq!(iter.next().unwrap(), bits![1]);
assert!(iter.next().is_none());

Iterates over mutable subslices separated by bits that match a predicate. The matched bit is not contained in the yielded bit-slices.

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded subslices for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

Original

slice::split_mut

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0, 1, 0, 1, 0];
//                         ^     ^
for group in bits.split_mut(|_pos, bit| *bit) {
  group.set(0, true);
}
assert_eq!(bits, bits![1, 0, 1, 1, 1, 1]);

Iterates over subslices separated by bits that match a predicate. Unlike .split(), this does include the matching bit as the last bit in the yielded bit-slice.

Original

slice::split_inclusive

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .split_inclusive_mut() has the same splitting logic, but each yielded bit-slice is mutable.
  • .split() does not include the matched bit in the yielded bit-slice.
Examples
use bitvec::prelude::*;

let bits = bits![0, 0, 1, 0, 1];
//                     ^     ^
let mut iter = bits.split_inclusive(|_pos, bit| *bit);

assert_eq!(iter.next().unwrap(), bits![0, 0, 1]);
assert_eq!(iter.next().unwrap(), bits![0, 1]);
assert!(iter.next().is_none());

Iterates over mutable subslices separated by bits that match a predicate. Unlike .split_mut(), this does include the matching bit as the last bit in the bit-slice.

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded subslices for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

Original

slice::split_inclusive_mut

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .split_inclusive() has the same splitting logic, but each yielded bit-slice is immutable.
  • .split_mut() does not include the matched bit in the yielded bit-slice.
Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0, 0, 0, 0];
//                         ^
for group in bits.split_inclusive_mut(|pos, _bit| pos % 3 == 2) {
  group.set(0, true);
}
assert_eq!(bits, bits![1, 0, 0, 1, 0]);

Iterates over subslices separated by bits that match a predicate, from the back edge. The matched bit is not contained in the yielded bit-slices.

Original

slice::rsplit

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .rsplit_mut() has the same splitting logic, but each yielded bit-slice is mutable.
  • .split() iterates from the front of the bit-slice instead of the back.
  • .rsplitn() times out after n yields.
Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 1, 0];
//                     ^
let mut iter = bits.rsplit(|pos, _bit| pos % 3 == 2);

assert_eq!(iter.next().unwrap(), bits![0]);
assert_eq!(iter.next().unwrap(), bits![0, 1]);
assert!(iter.next().is_none());

If the last bit is matched, then an empty bit-slice will be the first item yielded by the iterator. Similarly, if the first bit in the bit-slice matches, then an empty bit-slice will be the last item yielded.

use bitvec::prelude::*;

let bits = bits![0, 0, 1];
//                     ^
let mut iter = bits.rsplit(|_pos, bit| *bit);

assert!(iter.next().unwrap().is_empty());
assert_eq!(iter.next().unwrap(), bits![0; 2]);
assert!(iter.next().is_none());

If two yielded bits are directly adjacent, then an empty bit-slice will be yielded between them:

use bitvec::prelude::*;

let bits = bits![1, 0, 0, 1];
//                  ^  ^
let mut iter = bits.split(|_pos, bit| !*bit);

assert_eq!(iter.next().unwrap(), bits![1]);
assert!(iter.next().unwrap().is_empty());
assert_eq!(iter.next().unwrap(), bits![1]);
assert!(iter.next().is_none());

Iterates over mutable subslices separated by bits that match a predicate, from the back. The matched bit is not contained in the yielded bit-slices.

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded subslices for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

Original

slice::rsplit_mut

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .rsplit() has the same splitting logic, but each yielded bit-slice is immutable.
  • .split_mut() iterates from the front of the bit-slice to the back.
  • .rsplitn_mut() iterates from the front of the bit-slice to the back.
Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0, 1, 0, 1, 0];
//                         ^     ^
for group in bits.rsplit_mut(|_pos, bit| *bit) {
  group.set(0, true);
}
assert_eq!(bits, bits![1, 0, 1, 1, 1, 1]);

Iterates over subslices separated by bits that match a predicate, giving up after yielding n times. The nth yield contains the rest of the bit-slice. As with .split(), the yielded bit-slices do not contain the matched bit.

Original

slice::splitn

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .splitn_mut() has the same splitting logic, but each yielded bit-slice is mutable.
  • .rsplitn() iterates from the back of the bit-slice instead of the front.
  • .split() has the same splitting logic, but never times out.
Examples
use bitvec::prelude::*;

let bits = bits![0, 0, 1, 0, 1, 0];
let mut iter = bits.splitn(2, |_pos, bit| *bit);

assert_eq!(iter.next().unwrap(), bits![0, 0]);
assert_eq!(iter.next().unwrap(), bits![0, 1, 0]);
assert!(iter.next().is_none());

Iterates over mutable subslices separated by bits that match a predicate, giving up after yielding n times. The nth yield contains the rest of the bit-slice. As with .split_mut(), the yielded bit-slices do not contain the matched bit.

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded subslices for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

Original

slice::splitn_mut

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .splitn() has the same splitting logic, but each yielded bit-slice is immutable.
  • .rsplitn_mut() iterates from the back of the bit-slice instead of the front.
  • .split_mut() has the same splitting logic, but never times out.
Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0, 1, 0, 1, 0];
for group in bits.splitn_mut(2, |_pos, bit| *bit) {
  group.set(0, true);
}
assert_eq!(bits, bits![1, 0, 1, 1, 1, 0]);

Iterates over mutable subslices separated by bits that match a predicate from the back edge, giving up after yielding n times. The nth yield contains the rest of the bit-slice. As with .split_mut(), the yielded bit-slices do not contain the matched bit.

Original

slice::rsplitn

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .rsplitn_mut() has the same splitting logic, but each yielded bit-slice is mutable.
  • .splitn(): iterates from the front of the bit-slice instead of the back.
  • .rsplit() has the same splitting logic, but never times out.
Examples
use bitvec::prelude::*;

let bits = bits![0, 0, 1, 1, 0];
//                        ^
let mut iter = bits.rsplitn(2, |_pos, bit| *bit);

assert_eq!(iter.next().unwrap(), bits![0]);
assert_eq!(iter.next().unwrap(), bits![0, 0, 1]);
assert!(iter.next().is_none());

Iterates over mutable subslices separated by bits that match a predicate from the back edge, giving up after yielding n times. The nth yield contains the rest of the bit-slice. As with .split_mut(), the yielded bit-slices do not contain the matched bit.

Iterators do not require that each yielded item is destroyed before the next is produced. This means that each bit-slice yielded must be marked as aliased. If you are using this in a loop that does not collect multiple yielded subslices for the same scope, then you can remove the alias marking by calling the (unsafe) method .remove_alias() on the iterator.

Original

slice::rsplitn_mut

API Differences

The predicate function receives the index being tested as well as the bit value at that index. This allows the predicate to have more than one bit of information about the bit-slice being traversed.

Sibling Methods
  • .rsplitn() has the same splitting logic, but each yielded bit-slice is immutable.
  • .splitn_mut() iterates from the front of the bit-slice instead of the back.
  • .rsplit_mut() has the same splitting logic, but never times out.
Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0, 1, 0, 0, 1, 0, 0, 0];
for group in bits.rsplitn_mut(2, |_idx, bit| *bit) {
  group.set(0, true);
}
assert_eq!(bits, bits![1, 0, 1, 0, 0, 1, 1, 0, 0]);
//                     ^ group 2         ^ group 1

Tests if the bit-slice contains the given sequence anywhere within it.

This scans over self.windows(other.len()) until one of the windows matches. The search key does not need to share type parameters with the bit-slice being tested, as the comparison is bit-wise. However, sharing type parameters will accelerate the comparison.

Original

slice::contains

Examples
use bitvec::prelude::*;

let bits = bits![0, 0, 1, 0, 1, 1, 0, 0];
assert!( bits.contains(bits![0, 1, 1, 0]));
assert!(!bits.contains(bits![1, 0, 0, 1]));

Tests if the bit-slice begins with the given sequence.

The search key does not need to share type parameters with the bit-slice being tested, as the comparison is bit-wise. However, sharing type parameters will accelerate the comparison.

Original

slice::starts_with

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 1, 0];
assert!( bits.starts_with(bits![0, 1]));
assert!(!bits.starts_with(bits![1, 0]));

This always returns true if the needle is empty:

use bitvec::prelude::*;

let bits = bits![0, 1, 0];
let empty = bits![];
assert!(bits.starts_with(empty));
assert!(empty.starts_with(empty));

Tests if the bit-slice ends with the given sequence.

The search key does not need to share type parameters with the bit-slice being tested, as the comparison is bit-wise. However, sharing type parameters will accelerate the comparison.

Original

slice::ends_with

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 1, 0];
assert!( bits.ends_with(bits![1, 0]));
assert!(!bits.ends_with(bits![0, 1]));

This always returns true if the needle is empty:

use bitvec::prelude::*;

let bits = bits![0, 1, 0];
let empty = bits![];
assert!(bits.ends_with(empty));
assert!(empty.ends_with(empty));

Removes a prefix bit-slice, if present.

Like .starts_with(), the search key does not need to share type parameters with the bit-slice being stripped. If self.starts_with(suffix), then this returns Some(&self[prefix.len() ..]), otherwise it returns None.

Original

slice::strip_prefix

API Differences

BitSlice does not support pattern searches; instead, it permits self and prefix to differ in type parameters.

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 0, 1, 0, 1, 1, 0];
assert_eq!(bits.strip_prefix(bits![0, 1]).unwrap(), bits[2 ..]);
assert_eq!(bits.strip_prefix(bits![0, 1, 0, 0,]).unwrap(), bits[4 ..]);
assert!(bits.strip_prefix(bits![1, 0]).is_none());

Removes a suffix bit-slice, if present.

Like .ends_with(), the search key does not need to share type parameters with the bit-slice being stripped. If self.ends_with(suffix), then this returns Some(&self[.. self.len() - suffix.len()]), otherwise it returns None.

Original

slice::strip_suffix

API Differences

BitSlice does not support pattern searches; instead, it permits self and suffix to differ in type parameters.

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 0, 1, 0, 1, 1, 0];
assert_eq!(bits.strip_suffix(bits![1, 0]).unwrap(), bits[.. 7]);
assert_eq!(bits.strip_suffix(bits![0, 1, 1, 0]).unwrap(), bits[.. 5]);
assert!(bits.strip_suffix(bits![0, 1]).is_none());

Rotates the contents of a bit-slice to the left (towards the zero index).

This essentially splits the bit-slice at by, then exchanges the two pieces. self[.. by] becomes the first section, and is then followed by self[.. by].

The implementation is batch-accelerated where possible. It should have a runtime complexity much lower than O(by).

Original

slice::rotate_left

Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0, 1, 0, 1, 0];
//      split occurs here ^
bits.rotate_left(2);
assert_eq!(bits, bits![1, 0, 1, 0, 0, 0]);

Rotates the contents of a bit-slice to the right (away from the zero index).

This essentially splits the bit-slice at self.len() - by, then exchanges the two pieces. self[len - by ..] becomes the first section, and is then followed by self[.. len - by].

The implementation is batch-accelerated where possible. It should have a runtime complexity much lower than O(by).

Original

slice::rotate_right

Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0, 1, 1, 1, 0];
//            split occurs here ^
bits.rotate_right(2);
assert_eq!(bits, bits![1, 0, 0, 0, 1, 1]);

Fills the bit-slice with a given bit.

This is a recent stabilization in the standard library. bitvec previously offered this behavior as the novel API .set_all(). That method name is now removed in favor of this standard-library analogue.

Original

slice::fill

Examples
use bitvec::prelude::*;

let bits = bits![mut 0; 5];
bits.fill(true);
assert_eq!(bits, bits![1; 5]);

Fills the bit-slice with bits produced by a generator function.

Original

slice::fill_with

API Differences

The generator function receives the index of the bit being initialized as an argument.

Examples
use bitvec::prelude::*;

let bits = bits![mut 0; 5];
bits.fill_with(|idx| idx % 2 == 0);
assert_eq!(bits, bits![1, 0, 1, 0, 1]);
👎 Deprecated:

use .clone_from_bitslice() instead

👎 Deprecated:

use .copy_from_bitslice() instead

Copies a span of bits to another location in the bit-slice.

src is the range of bit-indices in the bit-slice to copy, and dest is the starting index of the destination range. srcanddest .. dest + src.len()are permitted to overlap; the copy will automatically detect and manage this. However, bothsrcanddest .. dest + src.len()**must** fall within the bounds ofself`.

Original

slice::copy_within

Panics

This panics if either the source or destination range exceed self.len().

Examples
use bitvec::prelude::*;

let bits = bits![mut 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0];
bits.copy_within(1 .. 5, 8);
//                        v  v  v  v
assert_eq!(bits, bits![1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0]);
//                                             ^  ^  ^  ^
👎 Deprecated:

use .swap_with_bitslice() instead

Produces bit-slice view(s) with different underlying storage types.

This may have unexpected effects, and you cannot assume that before[idx] == after[idx]! Consult the tables in the manual for information about memory layouts.

Original

slice::align_to

Notes

Unlike the standard library documentation, this explicitly guarantees that the middle bit-slice will have maximal size. You may rely on this property.

Safety

You may not use this to cast away alias protections. Rust does not have support for higher-kinded types, so this cannot express the relation Outer<T> -> Outer<U> where Outer: BitStoreContainer, but memory safety does require that you respect this rule. Reälign integers to integers, Cells to Cells, and atomics to atomics, but do not cross these boundaries.

Examples
use bitvec::prelude::*;

let bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
let bits = bytes.view_bits::<Lsb0>();
let (pfx, mid, sfx) = unsafe {
  bits.align_to::<u16>()
};
assert!(pfx.len() <= 8);
assert_eq!(mid.len(), 48);
assert!(sfx.len() <= 8);

Produces bit-slice view(s) with different underlying storage types.

This may have unexpected effects, and you cannot assume that before[idx] == after[idx]! Consult the tables in the manual for information about memory layouts.

Original

slice::align_to_mut

Notes

Unlike the standard library documentation, this explicitly guarantees that the middle bit-slice will have maximal size. You may rely on this property.

Safety

You may not use this to cast away alias protections. Rust does not have support for higher-kinded types, so this cannot express the relation Outer<T> -> Outer<U> where Outer: BitStoreContainer, but memory safety does require that you respect this rule. Reälign integers to integers, Cells to Cells, and atomics to atomics, but do not cross these boundaries.

Examples
use bitvec::prelude::*;

let mut bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
let bits = bytes.view_bits_mut::<Lsb0>();
let (pfx, mid, sfx) = unsafe {
  bits.align_to_mut::<u16>()
};
assert!(pfx.len() <= 8);
assert_eq!(mid.len(), 48);
assert!(sfx.len() <= 8);
👎 Deprecated:

use .to_bitvec() instead

Creates a bit-vector by repeating a bit-slice n times.

Original

slice::repeat

Panics

This method panics if self.len() * n exceeds the BitVec capacity.

Examples
use bitvec::prelude::*;

assert_eq!(bits![0, 1].repeat(3), bitvec![0, 1, 0, 1, 0, 1]);

This panics by exceeding bit-vector maximum capacity:

use bitvec::prelude::*;

bits![0, 1].repeat(BitSlice::<usize, Lsb0>::MAX_BITS);

Gets a raw pointer to the zeroth bit of the bit-slice.

Original

slice::as_ptr

API Differences

This is renamed in order to indicate that it is returning a bitvec structure, not a raw pointer.

Gets a raw, write-capable pointer to the zeroth bit of the bit-slice.

Original

slice::as_mut_ptr

API Differences

This is renamed in order to indicate that it is returning a bitvec structure, not a raw pointer.

Views the bit-slice as a half-open range of bit-pointers, to its first bit in the bit-slice and first bit beyond it.

Original

slice::as_ptr_range

API Differences

This is renamed to indicate that it returns a bitvec structure, rather than an ordinary Range.

Notes

BitSlice does define a .as_ptr_range(), which returns a Range<BitPtr>. BitPtrRange has additional capabilities that Range<*const T> and Range<BitPtr> do not.

Views the bit-slice as a half-open range of write-capable bit-pointers, to its first bit in the bit-slice and the first bit beyond it.

Original

slice::as_mut_ptr_range

API Differences

This is renamed to indicate that it returns a bitvec structure, rather than an ordinary Range.

Notes

BitSlice does define a [.as_mut_ptr_range()], which returns a Range<BitPtr>. BitPtrRange has additional capabilities that Range<*mut T> and Range<BitPtr> do not.

Copies the bits from src into self.

self and src must have the same length.

Performance

If src has the same type arguments as self, it will use the same implementation as .copy_from_bitslice(); if you know that this will always be the case, you should prefer to use that method directly.

Only .copy_from_bitslice() is able to perform acceleration; this method is always required to perform a bit-by-bit crawl over both bit-slices.

Original

slice::clone_from_slice

API Differences

This is renamed to reflect that it copies from another bit-slice, not from an element slice.

In order to support general usage, it allows src to have different type parameters than self, at the cost of performance optimizations.

Panics

This panics if the two bit-slices have different lengths.

Examples
use bitvec::prelude::*;

Copies all bits from src into self, using batched acceleration when possible.

self and src must have the same length.

Original

slice::copy_from_slice

Panics

This panics if the two bit-slices have different lengths.

Examples
use bitvec::prelude::*;

Swaps the contents of two bit-slices.

self and other must have the same length.

Original

slice::swap_with_slice

API Differences

This method is renamed, as it takes a bit-slice rather than an element slice.

Panics

This panics if the two bit-slices have different lengths.

Examples
use bitvec::prelude::*;

let mut one = [0xA5u8, 0x69];
let mut two = 0x1234u16;
let one_bits = one.view_bits_mut::<Msb0>();
let two_bits = two.view_bits_mut::<Lsb0>();

one_bits.swap_with_bitslice(two_bits);

assert_eq!(one, [0x2C, 0x48]);
assert_eq!(two, 0x96A5);

Writes a new value into a single bit.

This is the replacement for *slice[index] = value;, as bitvec is not able to express that under the current IndexMut API signature.

Parameters
  • &mut self
  • index: The bit-index to set. It must be in 0 .. self.len().
  • value: The new bit-value to write into the bit at index.
Panics

This panics if index is out of bounds.

Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 1];
bits.set(0, true);
bits.set(1, false);

assert_eq!(bits, bits![1, 0]);

Writes a new value into a single bit, without bounds checking.

Parameters
  • &mut self
  • index: The bit-index to set. It must be in 0 .. self.len().
  • value: The new bit-value to write into the bit at index.
Safety

You must ensure that index is in the range 0 .. self.len().

This performs bit-pointer offset arithmetic without doing any bounds checks. If index is out of bounds, then this will issue an out-of-bounds access and will trigger memory unsafety.

Examples
use bitvec::prelude::*;

let mut data = 0u8;
let bits = &mut data.view_bits_mut::<Lsb0>()[.. 2];
assert_eq!(bits.len(), 2);
unsafe {
  bits.set_unchecked(3, true);
}
assert_eq!(data, 8);

Writes a new value into a bit, and returns its previous value.

Panics

This panics if index is not less than self.len().

Examples
use bitvec::prelude::*;

let bits = bits![mut 0];
assert!(!bits.replace(0, true));
assert!(bits[0]);

Writes a new value into a bit, returning the previous value, without bounds checking.

Safety

index must be less than self.len().

Examples
use bitvec::prelude::*;

let bits = bits![mut 0, 0];
let old = unsafe {
  let a = &mut bits[.. 1];
  a.replace_unchecked(1, true)
};
assert!(!old);
assert!(bits[1]);

Swaps two bits in a bit-slice, without bounds checking.

See .swap() for documentation.

Safety

You must ensure that a and b are both in the range 0 .. self.len().

This method performs bit-pointer offset arithmetic without doing any bounds checks. If a or b are out of bounds, then this will issue an out-of-bounds access and will trigger memory unsafety.

Splits a bit-slice at an index, without bounds checking.

See .split_at() for documentation.

Safety

You must ensure that mid is in the range 0 ..= self.len().

This method produces new bit-slice references. If mid is out of bounds, its behavior is library-level undefined. You must conservatively assume that an out-of-bounds split point produces compiler-level UB.

Splits a mutable bit-slice at an index, without bounds checking.

See .split_at_mut() for documentation.

Safety

You must ensure that mid is in the range 0 ..= self.len().

This method produces new bit-slice references. If mid is out of bounds, its behavior is library-level undefined. You must conservatively assume that an out-of-bounds split point produces compiler-level UB.

Copies bits from one region of the bit-slice to another region of itself, without doing bounds checks.

The regions are allowed to overlap.

Parameters
  • &mut self
  • src: The range within self from which to copy.
  • dst: The starting index within self at which to paste.
Effects

self[src] is copied to self[dest .. dest + src.len()]. The bits of self[src] are in an unspecified, but initialized, state.

Safety

src.end() and dest + src.len() must be entirely within bounds.

Examples
use bitvec::prelude::*;

let mut data = 0b1011_0000u8;
let bits = data.view_bits_mut::<Msb0>();

unsafe {
  bits.copy_within_unchecked(.. 4, 2);
}
assert_eq!(data, 0b1010_1100);

Partitions a bit-slice into maybe-contended and known-uncontended parts.

The documentation of BitDomain goes into this in more detail. In short, this produces a &BitSlice that is as large as possible without requiring alias protection, as well as any bits that were not able to be included in the unaliased bit-slice.

Partitions a mutable bit-slice into maybe-contended and known-uncontended parts.

The documentation of BitDomain goes into this in more detail. In short, this produces a &mut BitSlice that is as large as possible without requiring alias protection, as well as any bits that were not able to be included in the unaliased bit-slice.

Views the underlying memory of a bit-slice, removing alias protections where possible.

The documentation of Domain goes into this in more detail. In short, this produces a &[T] slice with alias protections removed, covering all elements that self completely fills. Partially-used elements on either the front or back edge of the slice are returned separately.

Views the underlying memory of a bit-slice, removing alias protections where possible.

The documentation of Domain goes into this in more detail. In short, this produces a &mut [T] slice with alias protections removed, covering all elements that self completely fills. Partially-used elements on the front or back edge of the slice are returned separately.

Counts the number of bits set to 1 in the bit-slice contents.

Examples
use bitvec::prelude::*;

let bits = bits![1, 1, 0, 0];
assert_eq!(bits[.. 2].count_ones(), 2);
assert_eq!(bits[2 ..].count_ones(), 0);
assert_eq!(bits![].count_ones(), 0);

Counts the number of bits cleared to 0 in the bit-slice contents.

Examples
use bitvec::prelude::*;

let bits = bits![1, 1, 0, 0];
assert_eq!(bits[.. 2].count_zeros(), 0);
assert_eq!(bits[2 ..].count_zeros(), 2);
assert_eq!(bits![].count_zeros(), 0);

Enumerates the index of each bit in a bit-slice set to 1.

This is a shorthand for a .enumerate().filter_map() iterator that selects the index of each true bit; however, its implementation is eligible for optimizations that the individual-bit iterator is not.

Specializations for the Lsb0 and Msb0 orderings allow processors with instructions that seek particular bits within an element to operate on whole elements, rather than on each bit individually.

Examples

This example uses .iter_ones(), a .filter_map() that finds the index of each set bit, and the known indices, in order to show that they have equivalent behavior.

use bitvec::prelude::*;

let bits = bits![0, 1, 0, 0, 1, 0, 0, 0, 1];

let iter_ones = bits.iter_ones();
let known_indices = [1, 4, 8].iter().copied();
let filter = bits.iter()
  .by_vals()
  .enumerate()
  .filter_map(|(idx, bit)| if bit { Some(idx) } else { None });
let all = iter_ones.zip(known_indices).zip(filter);

for ((iter_one, known), filtered) in all {
  assert_eq!(iter_one, known);
  assert_eq!(known, filtered);
}

Enumerates the index of each bit in a bit-slice cleared to 0.

This is a shorthand for a .enumerate().filter_map() iterator that selects the index of each false bit; however, its implementation is eligible for optimizations that the individual-bit iterator is not.

Specializations for the Lsb0 and Msb0 orderings allow processors with instructions that seek particular bits within an element to operate on whole elements, rather than on each bit individually.

Examples

This example uses .iter_zeros(), a .filter_map() that finds the index of each cleared bit, and the known indices, in order to show that they have equivalent behavior.

use bitvec::prelude::*;

let bits = bits![1, 0, 1, 1, 0, 1, 1, 1, 0];

let iter_zeros = bits.iter_zeros();
let known_indices = [1, 4, 8].iter().copied();
let filter = bits.iter()
  .by_vals()
  .enumerate()
  .filter_map(|(idx, bit)| if !bit { Some(idx) } else { None });
let all = iter_zeros.zip(known_indices).zip(filter);

for ((iter_zero, known), filtered) in all {
  assert_eq!(iter_zero, known);
  assert_eq!(known, filtered);
}

Finds the index of the first bit in the bit-slice set to 1.

Returns None if there is no true bit in the bit-slice.

Examples
use bitvec::prelude::*;

assert!(bits![].first_one().is_none());
assert!(bits![0].first_one().is_none());
assert_eq!(bits![0, 1].first_one(), Some(1));

Finds the index of the first bit in the bit-slice cleared to 0.

Returns None if there is no false bit in the bit-slice.

Examples
use bitvec::prelude::*;

assert!(bits![].first_zero().is_none());
assert!(bits![1].first_zero().is_none());
assert_eq!(bits![1, 0].first_zero(), Some(1));

Finds the index of the last bit in the bit-slice set to 1.

Returns None if there is no true bit in the bit-slice.

Examples
use bitvec::prelude::*;

assert!(bits![].last_one().is_none());
assert!(bits![0].last_one().is_none());
assert_eq!(bits![1, 0].last_one(), Some(0));

Finds the index of the last bit in the bit-slice cleared to 0.

Returns None if there is no false bit in the bit-slice.

Examples
use bitvec::prelude::*;

assert!(bits![].last_zero().is_none());
assert!(bits![1].last_zero().is_none());
assert_eq!(bits![0, 1].last_zero(), Some(0));

Counts the number of bits from the start of the bit-slice to the first bit set to 0.

This returns 0 if the bit-slice is empty.

Examples
use bitvec::prelude::*;

assert_eq!(bits![].leading_ones(), 0);
assert_eq!(bits![0].leading_ones(), 0);
assert_eq!(bits![1, 0].leading_ones(), 1);

Counts the number of bits from the start of the bit-slice to the first bit set to 1.

This returns 0 if the bit-slice is empty.

Examples
use bitvec::prelude::*;

assert_eq!(bits![].leading_zeros(), 0);
assert_eq!(bits![1].leading_zeros(), 0);
assert_eq!(bits![0, 1].leading_zeros(), 1);

Counts the number of bits from the end of the bit-slice to the last bit set to 0.

This returns 0 if the bit-slice is empty.

Examples
use bitvec::prelude::*;

assert_eq!(bits![].trailing_ones(), 0);
assert_eq!(bits![0].trailing_ones(), 0);
assert_eq!(bits![0, 1].trailing_ones(), 1);

Counts the number of bits from the end of the bit-slice to the last bit set to 1.

This returns 0 if the bit-slice is empty.

Examples
use bitvec::prelude::*;

assert_eq!(bits![].trailing_zeros(), 0);
assert_eq!(bits![1].trailing_zeros(), 0);
assert_eq!(bits![1, 0].trailing_zeros(), 1);

Tests if there is at least one bit set to 1 in the bit-slice.

Returns false when self is empty.

Examples
use bitvec::prelude::*;

assert!(!bits![].any());
assert!(!bits![0].any());
assert!(bits![0, 1].any());

Tests if every bit is set to 1 in the bit-slice.

Returns true when self is empty.

Examples
use bitvec::prelude::*;

assert!( bits![].all());
assert!(!bits![0].all());
assert!( bits![1].all());

Tests if every bit is cleared to 0 in the bit-slice.

Returns true when self is empty.

Examples
use bitvec::prelude::*;

assert!( bits![].not_any());
assert!(!bits![1].not_any());
assert!( bits![0].not_any());

Tests if at least one bit is cleared to 0 in the bit-slice.

Returns false when self is empty.

Examples
use bitvec::prelude::*;

assert!(!bits![].not_all());
assert!(!bits![1].not_all());
assert!( bits![0].not_all());

Tests if at least one bit is set to 1, and at least one bit is cleared to 0, in the bit-slice.

Returns false when self is empty.

Examples
use bitvec::prelude::*;

assert!(!bits![].some());
assert!(!bits![0].some());
assert!(!bits![1].some());
assert!( bits![0, 1].some());

Shifts the contents of a bit-slice “left” (towards the zero-index), clearing the “right” bits to 0.

This is a strictly-worse analogue to taking bits = &bits[by ..]: it has to modify the entire memory region that bits governs, and destroys contained information. Unless the actual memory layout and contents of your bit-slice matters to your program, you should probably prefer to munch your way forward through a bit-slice handle.

Note also that the “left” here is semantic only, and does not necessarily correspond to a left-shift instruction applied to the underlying integer storage.

This has no effect when by is 0. When by is self.len(), the bit-slice is entirely cleared to 0.

Panics

This panics if by is not less than self.len().

Examples
use bitvec::prelude::*;

let bits = bits![mut 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1];
// these bits are retained ^--------------------------^
bits.shift_left(2);
assert_eq!(bits, bits![1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0]);
// and move here       ^--------------------------^

let bits = bits![mut 1; 2];
bits.shift_left(2);
assert_eq!(bits, bits![0; 2]);

Shifts the contents of a bit-slice “right” (away from the zero-index), clearing the “left” bits to 0.

This is a strictly-worse analogue to taking `bits = &bits[.. bits.len()

  • by]: it must modify the entire memory region that bits` governs, and destroys contained information. Unless the actual memory layout and contents of your bit-slice matters to your program, you should probably prefer to munch your way backward through a bit-slice handle.

Note also that the “right” here is semantic only, and does not necessarily correspond to a right-shift instruction applied to the underlying integer storage.

This has no effect when by is 0. When by is self.len(), the bit-slice is entirely cleared to 0.

Panics

This panics if by is not less than self.len().

Examples
use bitvec::prelude::*;

let bits = bits![mut 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1];
// these bits stay   ^--------------------------^
bits.shift_right(2);
assert_eq!(bits, bits![0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1]);
// and move here             ^--------------------------^

let bits = bits![mut 1; 2];
bits.shift_right(2);
assert_eq!(bits, bits![0; 2]);

Writes a new value into a single bit, using alias-safe operations.

This is equivalent to .set(), except that it does not require an &mut reference, and allows bit-slices with alias-safe storage to share write permissions.

Parameters
  • &self: This method only exists on bit-slices with alias-safe storage, and so does not require exclusive access.
  • index: The bit index to set. It must be in 0 .. self.len().
  • value: The new bit-value to write into the bit at index.
Panics

This panics if index is out of bounds.

Examples
use bitvec::prelude::*;
use core::cell::Cell;

let bits: &BitSlice<_, _> = bits![Cell<usize>, Lsb0; 0, 1];
bits.set_aliased(0, true);
bits.set_aliased(1, false);

assert_eq!(bits, bits![1, 0]);

Writes a new value into a single bit, using alias-safe operations and without bounds checking.

This is equivalent to .set_unchecked(), except that it does not require an &mut reference, and allows bit-slices with alias-safe storage to share write permissions.

Parameters
  • &self: This method only exists on bit-slices with alias-safe storage, and so does not require exclusive access.
  • index: The bit index to set. It must be in 0 .. self.len().
  • value: The new bit-value to write into the bit at index.
Safety

The caller must ensure that index is not out of bounds.

Examples
use bitvec::prelude::*;
use core::cell::Cell;

let data = Cell::new(0u8);
let bits = &data.view_bits::<Lsb0>()[.. 2];
unsafe {
  bits.set_aliased_unchecked(3, true);
}
assert_eq!(data.get(), 8);

Copies a bit-slice into an owned bit-vector.

Since the new vector is freshly owned, this gets marked as ::Unalias to remove any guards that may have been inserted by the bit-slice’s history.

It does not use the underlying memory type, so that a BitSlice<_, Cell<_>> will produce a BitVec<_, Cell<_>>.

Original

slice::to_vec

Examples
use bitvec::prelude::*;

let bits = bits![0, 1, 0, 1];
let bv = bits.to_bitvec();
assert_eq!(bits, bv);

Trait Implementations

Converts this type into a mutable reference of the (usually inferred) input type.

Converts this type into a shared reference of the (usually inferred) input type.

Formats the value using the given formatter.

The resulting type after applying the & operator.

Performs the & operation. Read more

Performs the &= operation. Read more

Performs the &= operation. Read more

Performs the &= operation. Read more

Bit-Array Implementation of BitField

The BitArray implementation is only ever called when the entire bit-array is available for use, which means it can skip the bit-slice memory detection and instead use the underlying storage elements directly.

The implementation still performs the segmentation for each element contained in the array, in order to maintain value consistency so that viewing the array as a bit-slice is still able to correctly interact with data contained in it.

Little-Endian Integer Loading Read more

Big-Endian Integer Loading Read more

Little-Endian Integer Storing Read more

Big-Endian Integer Storing Read more

Integer Loading Read more

Integer Storing Read more

The resulting type after applying the | operator.

Performs the | operation. Read more

Performs the |= operation. Read more

Performs the |= operation. Read more

Performs the |= operation. Read more

The resulting type after applying the ^ operator.

Performs the ^ operation. Read more

Performs the ^= operation. Read more

Performs the ^= operation. Read more

Performs the ^= operation. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

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

The resulting type after dereferencing.

Dereferences the value.

Mutably dereferences the value.

Deserialize this value from the given Serde deserializer. Read more

Deserialize this value from the given Serde deserializer. Read more

Formats the value using the given formatter. Read more

Converts to this type from the input type.

Converts to this type from the input type.

Converts to this type from the input type.

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

The returned type after indexing.

Performs the indexing (container[index]) operation. Read more

Performs the mutable indexing (container[index]) operation. Read more

Which kind of iterator are we turning this into?

The type of the elements being iterated over.

Creates an iterator from a value. Read more

Which kind of iterator are we turning this into?

The type of the elements being iterated over.

Creates an iterator from a value. Read more

Which kind of iterator are we turning this into?

The type of the elements being iterated over.

Creates an iterator from a value. Read more

Formats the value using the given formatter.

The resulting type after applying the ! operator.

Performs the unary ! operation. Read more

Formats the value using the given formatter.

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Serialize this value into the given Serde serializer. Read more

Serialize this value into the given Serde serializer. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

Formats the value using the given formatter.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Converts self into T using Into<T>. Read more

Causes self to use its Binary implementation when Debug-formatted. Read more

Causes self to use its Display implementation when Debug-formatted. Read more

Causes self to use its LowerExp implementation when Debug-formatted. Read more

Causes self to use its LowerHex implementation when Debug-formatted. Read more

Causes self to use its Octal implementation when Debug-formatted. Read more

Causes self to use its Pointer implementation when Debug-formatted. Read more

Causes self to use its UpperExp implementation when Debug-formatted. Read more

Causes self to use its UpperHex implementation when Debug-formatted. Read more

Formats each item in a sequence. Read more

Converts to this type from the input type.

Returns the argument unchanged.

Calls U::from(self).

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

Pipes by value. This is generally the method you want to use. Read more

Borrows self and passes that borrow into the pipe function. Read more

Mutably borrows self and passes that borrow into the pipe function. Read more

Borrows self, then passes self.borrow() into the pipe function. Read more

Mutably borrows self, then passes self.borrow_mut() into the pipe function. Read more

Borrows self, then passes self.as_ref() into the pipe function.

Mutably borrows self, then passes self.as_mut() into the pipe function. Read more

Borrows self, then passes self.deref() into the pipe function.

Mutably borrows self, then passes self.deref_mut() into the pipe function. Read more

Immutable access to a value. Read more

Mutable access to a value. Read more

Immutable access to the Borrow<B> of a value. Read more

Mutable access to the BorrowMut<B> of a value. Read more

Immutable access to the AsRef<R> view of a value. Read more

Mutable access to the AsMut<R> view of a value. Read more

Immutable access to the Deref::Target of a value. Read more

Mutable access to the Deref::Target of a value. Read more

Calls .tap() only in debug builds, and is erased in release builds.

Calls .tap_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_borrow() only in debug builds, and is erased in release builds. Read more

Calls .tap_borrow_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_ref() only in debug builds, and is erased in release builds. Read more

Calls .tap_ref_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_deref() only in debug builds, and is erased in release builds. Read more

Calls .tap_deref_mut() only in debug builds, and is erased in release builds. Read more

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

Converts the given value to a String. Read more

Attempts to convert self into T using TryInto<T>. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.