Struct TopicAliasSend

pub struct TopicAliasSend { /* private fields */ }

Topic alias manager for sending MQTT packets

This manages the mapping between topic names and numeric aliases for outgoing MQTT PUBLISH packets to reduce packet size for frequently used topics.

According to MQTT v5.0 specification, one topic can have multiple aliases.

Implementations

impl TopicAliasSend

pub fn new(max_alias: u16) -> Self

Create a new TopicAliasSend with the specified maximum alias value

pub fn insert_or_update(&mut self, topic: &str, alias: u16)

Insert or update a topic-alias mapping

Parameters

• topic - The topic name (must not be empty)
• alias - The alias value (must be between MIN_ALIAS and max_alias)

Panics

Panics if topic is empty or alias is out of valid range

pub fn get(&mut self, alias: u16) -> Option<&str>

Get topic by alias and update access timestamp (affects LRU)

Parameters

• alias - The alias to look up

Returns

The topic name if found, None otherwise

pub fn peek(&self, alias: u16) -> Option<&str>

Peek topic by alias without updating access timestamp (does not affect LRU)

Parameters

• alias - The alias to look up

Returns

The topic name if found, None otherwise

pub fn find_by_topic(&self, topic: &str) -> Option<u16>

Find alias by topic name

Parameters

• topic - The topic name to look up

Returns

The first alias if found, None otherwise

pub fn clear(&mut self)

Clear all topic-alias mappings

pub fn get_lru_alias(&self) -> u16

Get the least recently used (LRU) alias

Returns either the first vacant alias or the oldest used alias

Returns

An alias value that can be reused

Panics

Panics if max_alias is 0

pub fn max(&self) -> u16

Get the maximum alias value