Struct BitSpan

pub struct BitSpan<'a, T: BitWord> { /* private fields */ }

A non-owning read-only view into a bit array.

BitSpan provides a view into a sequence of bits stored in memory, allowing read-only access to individual bits or ranges of bits. It can be used to efficiently operate on a subset of bits without copying or allocating memory.

The span is defined by:

• A pointer to the start of the word array
• A bit offset from the start of the first word
• A length in bits

Safety

This type uses raw pointers internally. The caller must ensure that:

• The referenced memory remains valid for the lifetime of the span
• The offset and length parameters don’t cause out-of-bounds access

Implementations

impl<'a, T: BitWord> BitSpan<'a, T>

pub fn from_raw_parts(ptr: *const T, offset: usize, len: usize) -> Self

Creates a new BitSpan from raw parts.

This function allows creating a span directly from a raw pointer, which is useful for interfacing with external memory or creating views into existing bit arrays.

Arguments

• ptr - A pointer to the word array (will be converted to non-null)
• offset - The bit offset from the start of the first word
• len - The number of bits in the span

Safety

The caller must ensure that:

• The pointer is valid for reads of len bits starting at offset
• The memory remains valid for the lifetime of the returned span

If ptr is null, a dangling pointer will be used. This is safe as long as len is 0, but will lead to undefined behavior otherwise.

Trait Implementations

impl<'a, 'b, T: BitWord> BitAndAssign<&'b BitSpan<'b, T>> for BitSpanMut<'a, T>

fn bitand_assign(&mut self, rhs: &'b BitSpan<'b, T>)

Performs the &= operation.

impl<'a, 'b, T: BitWord> BitOrAssign<&'b BitSpan<'b, T>> for BitSpanMut<'a, T>

fn bitor_assign(&mut self, rhs: &'b BitSpan<'b, T>)

Performs the |= operation.

impl<'a, T: BitWord> BitRead for BitSpan<'a, T>

type Iter<'b> = BitSpanIter<'b, T> where Self: 'b

The iterator type returned by the iter method.

fn len(&self) -> usize

Returns the number of bits in the span.

fn is_empty(&self) -> bool

Returns true if the span is empty or contains no set bits.

This implementation considers a span empty if either:

• It has zero length
• It has no bits set to 1

fn test(&self, idx: usize) -> bool

Tests if the bit at the given index is set.

Arguments

• idx - The index of the bit to test

Returns

true if the bit is set, false otherwise

Panics

Panics if idx is out of bounds (>= self.len).

fn count_ones(&self) -> usize

Counts the number of bits set to 1 in the span.

Returns

The number of bits set to 1

fn all(&self) -> bool

Returns true if all bits in the span are set to 1.

Returns

true if the span is non-empty and all bits are set to 1, false otherwise

fn any(&self) -> bool

Returns true if any bit in the span is set to 1.

Returns

true if at least one bit is set to 1, false otherwise

fn iter(&self) -> Self::Iter<'_>

Returns an iterator over the indices of bits set to 1.

Returns

An iterator that yields the indices of all bits set to 1 in ascending order

fn none(&self) -> bool

impl<'a, 'b, T: BitWord> BitXorAssign<&'b BitSpan<'b, T>> for BitSpanMut<'a, T>

fn bitxor_assign(&mut self, rhs: &'b BitSpan<'b, T>)

Performs the ^= operation.