Struct ResendReceiver 

pub struct ResendReceiver { /* private fields */ }

Go-Back-N receiver state machine.

In Go-Back-N ARQ, frames arriving out of order are not queued or reordered; they are immediately dropped and prompt a cumulative ACK of the latest contiguous in-order frame.

This state machine provides two-phase sequence progression (inspect and advance_in_order) to allow transport drivers to apply backpressure.

Implementations

impl ResendReceiver

pub fn new() -> Self

Creates a new receiver state machine with expected_seq = 0.

pub fn expected_seq(&self) -> u8

Returns the sequence number currently expected by the receiver.

pub fn inspect(&self, seq: u8) -> FrameStatus

Evaluates an incoming frame sequence number without advancing state.

Returns FrameStatus::InOrder if seq == expected_seq. Otherwise, returns FrameStatus::OutOfOrder with the cumulative ACK sequence to transmit.

pub fn advance_in_order(&mut self, seq: u8) -> Result<u8, UnexpectedSeqError>

Advances expected_seq by 1 and returns the cumulative ACK sequence to transmit.

Errors

Returns UnexpectedSeqError if seq != expected_seq.

pub fn accept_seq(&mut self, seq: u8) -> FrameStatus

Processes an incoming frame sequence number in a single step.

If seq == expected_seq, advances the sequence and returns FrameStatus::InOrder. Otherwise, returns FrameStatus::OutOfOrder with the cumulative ACK to send in response.

Callers implementing two-phase flow control (e.g. attempting non-blocking writes to bounded channels before committing sequence progression) should use inspect followed by advance_in_order instead.

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

Returns the current cumulative ACK sequence for out-of-order/duplicate frames.

If no frames have been received yet, returns None to suppress spurious ACK 255 emission on startup packet loss (BUG-PROT-02).

pub fn reset(&mut self)

Resets the receiver to expect sequence number 0.

Trait Implementations

impl Clone for ResendReceiver

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ResendReceiver

impl Debug for ResendReceiver

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

Formats the value using the given formatter.

impl Default for ResendReceiver

fn default() -> Self

Returns the “default value” for a type.

impl Eq for ResendReceiver

impl PartialEq for ResendReceiver

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ResendReceiver