Struct TansEncoder 

pub struct TansEncoder { /* private fields */ }

tANS encoder for a single stream.

Uses Arc<[T]> for immutable tables, making Clone O(1) instead of O(n). Only the mutable state field is copied on clone.

Implementations

impl TansEncoder

pub fn from_decode_table(decode_table: &FseTable) -> Self

Build a tANS encoder from a decode table.

Implements the exact algorithm from Zstd’s FSE_buildCTable_wksp.

pub fn init_state(&mut self, symbol: u8)

Initialize encoder state for a specific symbol.

Implements FSE_initCState2 from Zstd:

nbBitsOut = (deltaNbBits + (1<<15)) >> 16  // with rounding
value = (nbBitsOut << 16) - deltaNbBits
state = stateTable[(value >> nbBitsOut) + deltaFindState]

This sets up the encoder for the first (last in sequence) symbol without outputting any bits.

pub fn encode_symbol(&mut self, symbol: u8) -> (u32, u8)

Encode a symbol and return (bits, num_bits).

Implements FSE_encodeSymbol from Zstd:

nbBitsOut = (state + deltaNbBits) >> 16
output low nbBitsOut bits of state
state = stateTable[(state >> nbBitsOut) + deltaFindState]

pub fn get_state(&self) -> u32

Get current state for serialization.

The decoder reads this as the initial state. For the bitstream, we write (state - tableSize) masked to accuracy_log bits.

pub fn accuracy_log(&self) -> u8

Get accuracy log.

pub fn reset(&mut self)

Reset encoder for new stream.

Trait Implementations

impl Clone for TansEncoder

fn clone(&self) -> TansEncoder

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TansEncoder

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

Formats the value using the given formatter.