Struct BitReader 

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

Bit-level reader for JPEG entropy-coded data.

Handles JPEG byte-stuffing (0xFF00 → 0xFF) and marker detection. Bits are read MSB-first from a 32-bit internal buffer.

Implementations

impl<'a> BitReader<'a>

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

Create a new BitReader over the given byte slice. pos should point to the first byte of entropy-coded data (after SOS header).

pub fn read_bits(&mut self, count: u8) -> Result<u16>

Read count bits (1–16) and return them right-aligned.

pub fn peek_bits(&mut self, count: u8) -> Result<u16>

Peek at the top count bits without consuming them.

pub fn skip_bits(&mut self, count: u8)

Discard count bits (must have been peeked already).

pub fn byte_align(&mut self)

Align to the next byte boundary by discarding remaining bits in the current byte.

pub fn position(&self) -> usize

Current byte position in the underlying data.

pub fn marker_found(&self) -> Option<u8>

Returns the marker byte if a marker was encountered during reading.

pub fn check_restart_marker(&mut self) -> Result<Option<u8>>

Check if a restart marker (0xFFD0–0xFFD7) is present. Checks both the marker_found flag (set if fill_byte already consumed a RST marker during Huffman decoding) and the next bytes in the stream. If found, consume the marker and return the marker’s low nibble (0–7).