Struct crdts::pncounter::PNCounter

pub struct PNCounter<A: Ord> { /* private fields */ }

PNCounter allows the counter to be both incremented and decremented by representing the increments (P) and the decrements (N) in separate internal G-Counters.

Merge is implemented by merging the internal P and N counters. The value of the counter is P minus N.

Examples

use crdts::{PNCounter, CmRDT};

let mut a = PNCounter::new();
a.apply(a.inc("A"));
a.apply(a.inc("A"));
a.apply(a.dec("A"));
a.apply(a.inc("A"));

assert_eq!(a.read(), 2.into());

Implementations

impl<A: Ord + Clone> PNCounter<A>

pub fn new() -> Self

Produce a new PNCounter.

pub fn inc(&self, actor: A) -> Op<A>

Generate an Op to increment the counter.

pub fn dec(&self, actor: A) -> Op<A>

Generate an Op to increment the counter.

pub fn inc_many(&self, actor: A, steps: u64) -> Op<A>

Generate an Op to increment the counter by a number of steps.

pub fn dec_many(&self, actor: A, steps: u64) -> Op<A>

Generate an Op to decrement the counter by a number of steps.

pub fn read(&self) -> BigInt

Return the current value of this counter (P-N).

Trait Implementations

impl<A: Clone + Ord> Clone for PNCounter<A>

fn clone(&self) -> PNCounter<A>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<A: Ord + Clone + Debug> CmRDT for PNCounter<A>

type Op = Op<A>

Op defines a mutation to the CRDT. As long as Op’s from one actor are replayed in exactly the same order they were generated by that actor, the CRDT will converge. In other words, we must have a total ordering on each actors operations, while requiring only a partial order over all ops. E.g.

type Validation = <GCounter<A> as CmRDT>::Validation

The validation error returned by validate_op.

fn validate_op(&self, op: &Self::Op) -> Result<(), Self::Validation>

Some CRDT’s have stricter requirements on how they must be used. To avoid violating these requirements, CRDT’s provide an interface to optionally validate op’s before they are applied.

fn apply(&mut self, op: Self::Op)

Apply an Op to the CRDT

impl<A: Ord + Clone + Debug> CvRDT for PNCounter<A>

type Validation = <GCounter<A> as CvRDT>::Validation

The validation error returned by validate_merge.

fn validate_merge(&self, other: &Self) -> Result<(), Self::Validation>

Some CRDT’s have stricter requirements on how they must be used. To avoid violating these requirements, CRDT’s provide an interface to optionally validate merge compatibility before attempting to merge.

fn merge(&mut self, other: Self)

Merge the given CRDT into the current CRDT.

impl<A: Debug + Ord> Debug for PNCounter<A>

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

Formats the value using the given formatter.

impl<A: Ord> Default for PNCounter<A>

fn default() -> Self

Returns the “default value” for a type.

impl<'de, A> Deserialize<'de> for PNCounter<A>where A: Deserialize<'de> + Ord,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<A: Hash + Ord> Hash for PNCounter<A>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<A: PartialEq + Ord> PartialEq<PNCounter<A>> for PNCounter<A>

fn eq(&self, other: &PNCounter<A>) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

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

impl<A: Ord> ResetRemove<A> for PNCounter<A>

fn reset_remove(&mut self, clock: &VClock<A>)

Remove data that is strictly smaller than this clock

impl<A> Serialize for PNCounter<A>where A: Serialize + Ord,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<A: Eq + Ord> Eq for PNCounter<A>

impl<A: Ord> StructuralEq for PNCounter<A>

impl<A: Ord> StructuralPartialEq for PNCounter<A>