Struct Prunable 

pub struct Prunable<const N: usize> { /* private fields */ }

A prunable bitmap that stores data in chunks of N bytes.

Panics

Operations panic if bit / CHUNK_SIZE_BITS > usize::MAX. On 32-bit systems with N=32, this occurs at bit >= 1,099,511,627,776.

Implementations

impl<const N: usize> Prunable<N>

pub const CHUNK_SIZE_BITS: u64 = BitMap<N>::CHUNK_SIZE_BITS

The size of a chunk in bits.

pub fn new() -> Self

Create a new empty prunable bitmap.

pub fn new_with_pruned_chunks(pruned_chunks: usize) -> Result<Self, Error>

Create a new empty prunable bitmap with the given number of pruned chunks.

Errors

Returns an error if pruned_chunks violates the invariant that pruned_chunks as u64 * CHUNK_SIZE_BITS must not overflow u64.

pub fn len(&self) -> u64

Return the number of bits in the bitmap, irrespective of any pruning.

pub fn is_empty(&self) -> bool

Return true if the bitmap is empty.

pub fn is_chunk_aligned(&self) -> bool

Returns true if the bitmap length is aligned to a chunk boundary.

pub fn chunks_len(&self) -> usize

Return the number of unpruned chunks in the bitmap.

pub fn pruned_chunks(&self) -> usize

Return the number of pruned chunks.

pub fn pruned_bits(&self) -> u64

Return the number of pruned bits.

pub fn get_bit(&self, bit: u64) -> bool

Get the value of a bit.

Warning

Panics if the bit doesn’t exist or has been pruned.

pub fn get_chunk_containing(&self, bit: u64) -> &[u8; N]

Returns the bitmap chunk containing the specified bit.

Warning

Panics if the bit doesn’t exist or has been pruned.

pub fn get_bit_from_chunk(chunk: &[u8; N], bit: u64) -> bool

Get the value of a bit from its chunk. bit is an index into the entire bitmap, not just the chunk.

pub fn last_chunk(&self) -> (&[u8; N], u64)

Return the last chunk of the bitmap and its size in bits.

pub fn set_bit(&mut self, bit: u64, value: bool)

Set the value of the given bit.

Warning

Panics if the bit doesn’t exist or has been pruned.

pub fn push(&mut self, bit: bool)

Add a single bit to the end of the bitmap.

pub fn pop(&mut self) -> bool

Remove and return the last bit from the bitmap.

Warning

Panics if the bitmap is empty.

pub fn push_byte(&mut self, byte: u8)

Add a byte to the bitmap.

Warning

Panics if self.next_bit is not byte aligned.

pub fn push_chunk(&mut self, chunk: &[u8; N])

Add a chunk of bits to the bitmap.

Warning

Panics if self.next_bit is not chunk aligned.

pub fn pop_chunk(&mut self) -> [u8; N]

Remove and return the last complete chunk from the bitmap.

Warning

Panics if the bitmap has fewer than CHUNK_SIZE_BITS bits or if not chunk-aligned.

pub fn prune_to_bit(&mut self, bit: u64)

Prune all complete chunks before the chunk containing the given bit.

The chunk containing bit and all subsequent chunks are retained. All chunks before it are pruned.

If bit equals the bitmap length, this prunes all complete chunks while retaining the empty trailing chunk, preparing the bitmap for appending new data.

Warning

Panics if bit is greater than the bitmap length.

pub fn chunk_byte_bitmask(bit: u64) -> u8

Convert a bit into a bitmask for the byte containing that bit.

pub fn chunk_byte_offset(bit: u64) -> usize

Convert a bit into the index of the byte within a chunk containing the bit.

pub fn pruned_chunk(&self, bit: u64) -> usize

Convert a bit into the index of the chunk it belongs to within the bitmap, taking pruned chunks into account. That is, the returned value is a valid index into the inner bitmap.

Warning

Panics if the bit doesn’t exist or has been pruned.

pub fn unpruned_chunk(bit: u64) -> usize

Convert a bit into the number of the chunk it belongs to, ignoring any pruning.

Panics

Panics if bit / CHUNK_SIZE_BITS > usize::MAX.

pub fn get_chunk(&self, chunk: usize) -> &[u8; N]

Get a reference to a chunk by its index in the current bitmap Note this is an index into the chunks, not a bit.

Trait Implementations

impl<const N: usize> Clone for Prunable<N>

fn clone(&self) -> Prunable<N>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<const N: usize> Debug for Prunable<N>

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

Formats the value using the given formatter.

impl<const N: usize> Default for Prunable<N>

fn default() -> Self

Returns the “default value” for a type.

impl<const N: usize> EncodeSize for Prunable<N>

fn encode_size(&self) -> usize

Returns the encoded size of this value (in bytes).

impl<const N: usize> Read for Prunable<N>

type Cfg = u64

The Cfg type parameter allows passing configuration during the read process. This is crucial for safely decoding untrusted data, for example, by providing size limits for collections or strings.

fn read_cfg(buf: &mut impl Buf, max_len: &Self::Cfg) -> Result<Self, CodecError>

Reads a value from the buffer using the provided configuration cfg.

impl<const N: usize> Write for Prunable<N>

fn write(&self, buf: &mut impl BufMut)

Writes the binary representation of self to the provided buffer buf.