Struct SequenceManager 

pub struct SequenceManager { /* private fields */ }

Manages sequence numbers for a FIX session.

Uses atomic operations for thread-safe access without locks.

Implementations

impl SequenceManager

pub fn new() -> Self

Creates a new sequence manager with sequence numbers starting at 1.

pub fn with_initial(sender_seq: u64, target_seq: u64) -> Self

Creates a new sequence manager with specified starting values.

Arguments

• sender_seq - Initial sender sequence number
• target_seq - Initial target sequence number

pub fn next_sender_seq(&self) -> SeqNum

Returns the next sender sequence number without incrementing.

pub fn next_target_seq(&self) -> SeqNum

Returns the next target sequence number without incrementing.

pub fn allocate_sender_seq(&self) -> SeqNum

Allocates and returns the next sender sequence number.

This atomically increments the sequence number and returns the value before the increment.

Note: wraps silently on u64 overflow. Prefer try_allocate_sender_seq for venue-grade sessions where exhaustion must be an explicit error.

pub fn try_allocate_sender_seq(&self) -> Result<SeqNum, SequenceExhausted>

Allocates and returns the next sender sequence number, failing instead of wrapping when the counter is exhausted.

On success this atomically increments the counter and returns the value before the increment. On exhaustion the counter is left untouched; the session must perform a sequence reset (see SequenceExhausted) before more numbers can be allocated.

Errors

Returns SequenceExhausted if the counter has reached u64::MAX.

pub fn increment_target_seq(&self)

Increments the target sequence number.

Call this after successfully processing an incoming message.

Note: wraps silently on u64 overflow. Prefer try_increment_target_seq for venue-grade sessions where exhaustion must be an explicit error.

pub fn try_increment_target_seq(&self) -> Result<SeqNum, SequenceExhausted>

Increments the target sequence number, failing instead of wrapping when the counter is exhausted.

On success returns the new next expected target sequence number. On exhaustion the counter is left untouched; the session must perform a sequence reset (see SequenceExhausted) before more messages can be accepted.

Errors

Returns SequenceExhausted if the counter has reached u64::MAX.

pub fn set_sender_seq(&self, seq: u64)

Sets the next sender sequence number.

Arguments

• seq - The new sequence number

pub fn set_target_seq(&self, seq: u64)

Sets the next target sequence number.

Arguments

• seq - The new sequence number

pub fn reset(&self)

Resets both sequence numbers to 1.

pub fn validate_incoming(&self, received: u64) -> SequenceResult

Validates an incoming sequence number.

Arguments

• received - The received sequence number

Returns

• Ok(()) if the sequence number matches expected
• Err(SequenceResult::TooLow) if it’s a possible duplicate
• Err(SequenceResult::Gap) if there’s a gap

Trait Implementations

impl Debug for SequenceManager

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

Formats the value using the given formatter.

impl Default for SequenceManager

fn default() -> Self

Returns the “default value” for a type.