Struct HlcTimestamp

pub struct HlcTimestamp(/* private fields */);

Hybrid logical clock (HLC) timestamp.

This is a lock-free implementation of a hybrid logical clock (HLC) timestamp.

The timestamp is represented as a 64-bit unsigned integer. The upper 42 bits represent the physical time in milliseconds since a custom epoch, and the lower 22 bits represent the logical clock count.

Normally, you don’t need to worry about the details of the representation.

Whenever you need to create a new timestamp, use the new() to create a timestamp with the current time, or from_parts() to create a timestamp with a specific Unix timestamp (in ms) and logical clock count.

When you need to update the timestamp, use the update() method.

Finally, you can use the as_u64() method to get the raw data, which is guaranteed to be monotonically increasing and capturing the happens-before relationship.

To get the physical time and logical clock count, use the timestamp() and count() methods respectively.

Implementations

impl HlcTimestamp

pub fn new() -> Self

Creates a new HLC timestamp.

pub fn from_parts(pt: i64, lc: u64) -> HlcResult<Self>

Creates a new HLC timestamp from the given physical time and logical clock count.

pub fn update<F>(&self, new_values: F) -> HlcResult<HlcTimestamp>

where F: Fn(i64, u64) -> HlcResult<(i64, u64)>,

Sets the physical time and logical clock count.

Expected closure gets the current physical time and logical clock count at the moment of the call and must return the new values for both.

This is an atomic operation that ensures thread safety in a lock-free fashion. Either both values are updated or none are.

pub fn as_u64(&self) -> u64

Returns the current HLC timestamp as a number.

pub fn from_u64(value: u64) -> HlcResult<Self>

Creates a new HLC timestamp from the given u64 value.

The encoded value should be in the format of the HLC timestamp.

pub fn parts(&self) -> (i64, u64)

Returns the current physical timestamp and logical clock count as a tuple.

This operation is atomic, as it uses a single load operation to get the inner value.

Trait Implementations

impl Clone for HlcTimestamp

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for HlcTimestamp

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

Formats the value using the given formatter.

impl Default for HlcTimestamp

fn default() -> Self

Returns the “default value” for a type.

impl Ord for HlcTimestamp

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for HlcTimestamp

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 PartialOrd for HlcTimestamp

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl TryFrom<u64> for HlcTimestamp

type Error = HlcError

The type returned in the event of a conversion error.

fn try_from(value: u64) -> Result<Self, Self::Error>

Performs the conversion.

impl Eq for HlcTimestamp