Struct Instant 

pub struct Instant<P: Profile> { /* private fields */ }

A point in absolute time: an unsigned integer count of ticks since the datum, parameterised by profile at the type level (Rule P).

Cross-profile arithmetic and comparison do not compile. Instant<UC1> and Instant<UC2> are distinct types with no coercion between them; conversion is available only through Instant::rebase, which reports the constant shift.

Implementations

impl<P: Profile> Instant<P>

pub fn to_ucid(&self) -> Result<Ucid>

The instant’s UCID (§7.2). UCAL-E0031 above 2^256 (Rule I).

Not a unique identifier: see the module documentation and Rule I.

pub fn from_ucid(u: &Ucid) -> Result<Self>

Recover an instant from its UCID.

pub fn from_bytes_slice(bytes: &[u8]) -> Result<Self>

Decode the canonical binary form from a slice, checking the width.

UCAL-E0030 if the slice is not exactly 64 bytes. The array-typed Instant::from_bytes makes that unrepresentable; this exists for the boundary where a length arrives from outside the type system — a socket, a column, a file — which is precisely where Rule B’s fixed width needs enforcing rather than assuming.

impl<P: Profile> Instant<P>

The datum, as a const, on the default backend only.

§13 specifies pub const ZERO: Self. That is achievable when Ticks is const-constructible, which it is on the default backend and is not on bigint (a heap value cannot be a const). Instant::zero is the portable form and is available on both.

pub const ZERO: Self

Tick 0 — the datum (Rule Z, Rule Q).

impl<P: Profile> Instant<P>

pub fn zero() -> Self

Tick 0 — the datum. A stipulated reference point, conventionally identified with the FLRW t→0 limit; not a measurement and not an observed event (Rule Q, N17).

pub fn from_ticks(ticks: Ticks) -> Result<Self>

Construct from a tick count, rejecting values outside the profile domain.

pub fn from_u64(v: u64) -> Result<Self>

Construct from a small tick count.

pub fn ticks(&self) -> &Ticks

The raw tick count.

pub fn tier_value(&self, tier: Tier) -> u16

The decimal group value at a tier, in 0..=3124.

pub fn groups(&self, from: Tier, to: Tier) -> Result<Vec<u16>>

Group values for tiers from down to to, most significant first.

pub fn floor_to(&self, tier: Tier) -> Self

Truncate toward the datum. Truncation is rounding (G3, Rule G).

pub fn ceil_to(&self, tier: Tier) -> Result<Self>

Round away from the datum, failing on domain exit.

pub fn round_to(&self, tier: Tier, mode: Rounding) -> Result<Self>

Round to a tier under an explicit mode (Rule R).

pub fn window_at(&self, precision: Precision) -> Result<Window<P>>

The closed interval a value stated at this precision denotes (Rule T).

For Precision::Tick this is the degenerate window [v, v]. For a tier it is [floor, floor + 5^e - 1] — never a bare instant, which is what keeps failure mode F2 closed.

pub fn since(&self, earlier: &Self) -> Result<Delta>

Elapsed ticks since an earlier instant. UCAL-E0020 if earlier is later than self — Rule Z admits no negative result.

pub fn between(&self, other: &Self) -> Signed

The signed difference self - other. Always succeeds.

pub fn checked_add(&self, d: &Delta) -> Result<Self>

Advance by a magnitude, failing on domain exit (UCAL-E0021).

pub fn checked_sub(&self, d: &Delta) -> Result<Self>

Retreat by a magnitude, failing before the datum (UCAL-E0020).

pub fn to_bytes(&self) -> [u8; 64]

Canonical binary form: 64 bytes, big-endian, zero-padded (§7.1, Rule B).

Byte order is chronological order, so the encoding is directly usable as a database key. Identical on every backend, which is what makes the cross-backend differential test a conformance test (Rule W).

pub fn from_bytes(bytes: &[u8; 64]) -> Result<Self>

Inverse of Instant::to_bytes.

pub fn rebase<Q: Profile>(&self) -> Result<(Instant<Q>, Signed)>

Reinterpret under another profile, reporting the constant tick shift (D-14, Rule P).

The shift is Q::origin_offset() - P::origin_offset(): both profiles date from their own datum, so rebasing is a translation. Returns the new instant and the shift that was applied, because a caller that does not see the shift cannot audit the conversion.

Trait Implementations

impl<P: Profile> Clone for Instant<P>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<P: Profile> Copy for Instant<P>

Available on crate feature u512 only.

impl<P: Profile> Debug for Instant<P>

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

Formats the value using the given formatter.

impl<P: Profile> Eq for Instant<P>

impl<P: Profile> Hash for Instant<P>

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<P: Profile> Ord for Instant<P>

Rule M: for instants in one profile, exactly one of a < b, a = b, a > b holds, and it is the chronological order. Rule P makes the “in one profile” part a type-level guarantee rather than a runtime check.

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<P: Profile> PartialEq for Instant<P>

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

Equality operator ==.

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

Inequality operator !=.

impl<P: Profile> PartialOrd for Instant<P>

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.