Struct BitReader 

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

High-performance bit-level reader over a byte slice.

Uses safe unaligned 64-bit reads via u64::from_le_bytes for fast bit extraction. Every read returns Result<T> with overflow checking.

Implementations

impl<'a> BitReader<'a>

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

Create a new reader starting at bit 0 of data.

pub fn bits_remaining(&self) -> usize

Number of bits between the cursor and the end of the buffer.

pub fn position(&self) -> usize

Current bit offset from the start of the buffer.

pub fn read_bits(&mut self, n: usize) -> Result<u64>

Read up to 64 bits. Returns the value right-aligned in a u64.

pub fn peek_bits(&self, n: usize) -> Result<u64>

Peek at up to 64 bits without advancing the position.

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

Read a single bit as a boolean.

pub fn read_u8(&mut self) -> Result<u8>

Read 8 bits as a u8.

pub fn read_u16(&mut self) -> Result<u16>

Read 16 bits as a little-endian u16.

pub fn read_u32(&mut self) -> Result<u32>

Read 32 bits as a little-endian u32.

pub fn read_u64(&mut self) -> Result<u64>

Read 64 bits as a little-endian u64.

pub fn read_f32(&mut self) -> Result<f32>

Read 32 bits and reinterpret as an IEEE 754 f32.

pub fn read_bytes(&mut self, buf: &mut [u8]) -> Result<()>

Read N bytes into the provided buffer.

pub fn read_bits_to_bytes(&mut self, buf: &mut [u8], bits: usize) -> Result<()>

Read a specified number of bits into a byte buffer, filling LSB-first.

pub fn read_uvarint32(&mut self) -> Result<u32>

Read an unsigned varint (up to 32 bits).

pub fn read_uvarint64(&mut self) -> Result<u64>

Read an unsigned varint (up to 64 bits).

pub fn read_varint32(&mut self) -> Result<i32>

Read a signed varint (zigzag encoded, 32-bit).

pub fn read_varint64(&mut self) -> Result<i64>

Read a signed varint (zigzag encoded, 64-bit).

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

Valve’s variable-length unsigned integer encoding.

Reads 6 bits; bits 4-5 select the total width: 00 → 6 bits, 01 → 4+4, 10 → 4+8, 11 → 4+28.

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

Field-path variant of ubitvar — cascading 1-bit selectors.

Used exclusively for encoding field path operation indices: 2, 4, 10, 17, or 31 bits depending on which prefix bit is set.

pub fn read_bitcoord(&mut self) -> Result<f32>

Read a coordinate value.

pub fn read_bitnormal(&mut self) -> Result<f32>

Read a normal component (sign + 11-bit fraction).

pub fn read_bitvec3coord(&mut self) -> Result<[f32; 3]>

Read a 3D coordinate vector.

pub fn read_bitvec3normal(&mut self) -> Result<[f32; 3]>

Read a 3D normal vector (2 components + derived Z).

pub fn read_bitangle(&mut self, n: usize) -> Result<f32>

Read an angle encoded as N bits, returning degrees in [0, 360).

pub fn read_string(&mut self) -> Result<String>

Read a null-terminated string.

pub fn read_string_into(&mut self, buf: &mut [u8]) -> Result<usize>

Read a string into the provided buffer, returning bytes written (excluding null).

pub fn read_string_raw(&mut self, buf: &mut Vec<u8>) -> Result<usize>

Read a string as raw bytes into a Vec, returning bytes written (excluding null).

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

Skip forward by N bits.

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

Skip a varint without decoding it.

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

Skip a bitcoord value.

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

Skip a bitnormal value.

pub fn skip_bitvec3coord(&mut self) -> Result<()>

Skip a 3D coordinate vector.

pub fn skip_bitvec3normal(&mut self) -> Result<()>

Skip a 3D normal vector.

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

Skip a null-terminated string.