Struct GCounter 

pub struct GCounter<const MAX_NODES: usize = 32> { /* private fields */ }

A Grow-only Counter (G-Counter).

Each node can only increment its own count. The counter value is the sum of all node counts. Merge takes the maximum of each node’s count.

Memory usage: approximately 4 + (MAX_NODES * 8) bytes. Default capacity of 32 nodes ≈ 260 bytes.

Example

use peat_lite::{GCounter, NodeId};

let node1 = NodeId::new(1);
let node2 = NodeId::new(2);

let mut counter1 = GCounter::<8>::new();
counter1.increment(node1, 5);

let mut counter2 = GCounter::<8>::new();
counter2.increment(node2, 3);

counter1.merge(&counter2);
assert_eq!(counter1.value(), 8);

Implementations

impl<const MAX_NODES: usize> GCounter<MAX_NODES>

pub const fn new() -> Self

Create a new empty counter.

pub fn value(&self) -> u64

Get the total counter value (sum of all node counts).

pub fn node_count(&self, node: NodeId) -> u32

Get a specific node’s count.

pub fn increment(&mut self, node: NodeId, delta: u32) -> Option<u32>

Increment the counter for a specific node.

Returns the new count for that node, or None if the counter is full and can’t add a new node.

pub fn inc(&mut self, node: NodeId) -> Option<u32>

Increment by 1.

pub fn merge(&mut self, other: &Self)

Merge with another counter.

Takes the maximum of each node’s count.

pub fn node_count_total(&self) -> usize

Get the number of nodes that have contributed to this counter.

pub fn is_empty(&self) -> bool

Check if this counter is empty (all counts are 0 or no nodes).

pub fn clear(&mut self)

Clear all counts.

pub fn iter(&self) -> impl Iterator<Item = (NodeId, u32)> + '_

Iterate over (node_id, count) pairs.

pub fn encode(&self) -> Vec<u8, 258>

Encode to bytes for transmission.

Format: [num_entries: u16][entry1][entry2]... Each entry: [node_id: 4B][count: 4B] = 8 bytes

pub fn decode(data: &[u8]) -> Option<Self>

Decode from bytes.

Trait Implementations

impl<const MAX_NODES: usize> Clone for GCounter<MAX_NODES>

fn clone(&self) -> GCounter<MAX_NODES>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<const MAX_NODES: usize> Debug for GCounter<MAX_NODES>

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

Formats the value using the given formatter.

impl<const MAX_NODES: usize> Default for GCounter<MAX_NODES>

fn default() -> Self

Returns the “default value” for a type.

impl<const MAX_NODES: usize> PartialEq for GCounter<MAX_NODES>

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<const MAX_NODES: usize> Eq for GCounter<MAX_NODES>