Struct BitReader 

pub struct BitReader<'a> { /* private fields */ }

A most-significant-bit-first reader over an AV1 byte slice.

Position is tracked in bits so byte_alignment and the byte-granular primitives (leb128, le) can assert and act on alignment.

Implementations

impl<'a> BitReader<'a>

pub fn new(data: &'a [u8]) -> Self

Wrap a byte slice. Reading starts at its first bit.

pub fn bit_position(&self) -> usize

The current position, in bits from the start.

pub fn bit_len(&self) -> usize

The total length of the underlying slice, in bits.

pub fn bits_left(&self) -> usize

Bits remaining before the end of the slice.

pub fn is_byte_aligned(&self) -> bool

Whether the reader sits exactly on a byte boundary.

pub fn byte_position(&self) -> usize

The current position in whole bytes — only meaningful when byte-aligned.

pub fn f(&mut self, n: u32) -> Result<u32>

f(n) — read n bits as an unsigned integer, MSB first (§4.10.2).

n is at most 32; the AV1 syntax never reads a wider f(n) in one call.

pub fn flag(&mut self) -> Result<bool>

Read a boolean flag — f(1) reported as bool.

pub fn uvlc(&mut self) -> Result<u32>

uvlc() — unsigned variable-length code (§4.10.3).

A run of zero bits terminated by a one, then that many value bits. A run of 32 or more leading zeros is the spec’s saturation case and yields u32::MAX.

pub fn le(&mut self, n: u32) -> Result<u64>

le(n) — an n-byte little-endian unsigned integer (§4.10.4).

Must be byte-aligned, which the syntax guarantees at every call site.

pub fn leb128(&mut self) -> Result<u64>

leb128() — a little-endian base-128 unsigned integer (§4.10.5).

At most eight bytes; a ninth continuation bit is malformed. Returns the value and the number of bytes consumed so callers can bound a payload.

pub fn su(&mut self, n: u32) -> Result<i32>

su(n) — a signed integer in n+1 bits, sign last (§4.10.6).

pub fn ns(&mut self, n: u32) -> Result<u32>

ns(n) — a non-symmetric unsigned integer over [0, n) (§4.10.7).

Uses one fewer bit for the smaller half of the range, so it is not a plain f. n == 0 reads nothing and yields 0.

pub fn byte_alignment(&mut self) -> Result<()>

Advance to the next byte boundary, requiring the skipped bits be zero (byte_alignment(), §5.3.5). AV1 mandates the padding be zero.

pub fn skip_bits(&mut self, n: usize) -> Result<()>

Skip n bits without interpreting them.