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use crate::{Dt, TSpan};
use core::cmp::Ordering;
use core::ops::{Add, AddAssign, Sub, SubAssign};
impl Add<TSpan> for Dt {
type Output = Self;
#[inline]
fn add(self, rhs: TSpan) -> Self {
self.add(rhs)
}
}
impl AddAssign<TSpan> for Dt {
#[inline]
fn add_assign(&mut self, rhs: TSpan) {
*self = self.add(rhs);
}
}
impl Sub<TSpan> for Dt {
type Output = Self;
#[inline]
fn sub(self, rhs: TSpan) -> Self {
self.sub(rhs)
}
}
impl SubAssign<TSpan> for Dt {
#[inline]
fn sub_assign(&mut self, rhs: TSpan) {
*self = self.sub(rhs);
}
}
impl Sub<Dt> for Dt {
type Output = TSpan;
#[inline]
fn sub(self, rhs: Dt) -> TSpan {
self.to_tai_since(rhs)
}
}
impl Dt {
/// Compares this `Dt` with another by converting both to the TAI timescale
/// (the library's canonical physical-time reference) and then comparing their
/// `(sec, attos)` pairs.
///
/// This is a `const fn` so it can be used in const contexts and is allocation-free.
/// It provides the total order used by `<`, `>`, `<=`, `>=`, `cmp`, etc.
///
/// Two `Dt`s that represent the exact same physical instant (after all
/// leap-second, relativistic, and scale conversions) compare as `Equal`, even if
/// they were constructed with different [`Scale`]s.
pub const fn cmp(self, other: Self) -> Ordering {
if self.sec < other.sec {
Ordering::Less
} else if self.sec > other.sec {
Ordering::Greater
} else if self.attos < other.attos {
Ordering::Less
} else if self.attos > other.attos {
Ordering::Greater
} else {
Ordering::Equal
}
}
/// Returns the smaller of two `Dt`s according to the total physical-time order
/// defined by [`Self::cmp`].
///
/// Both instants are converted to TAI internally, so the result is the physically
/// earlier instant even when the two `Dt`s belong to different [`Scale`]s
/// (leap seconds, relativistic offsets, etc. are all taken into account).
///
/// This is a `const fn` and can be used in const contexts.
#[inline]
pub const fn min(self, other: Self) -> Self {
match self.cmp(other) {
Ordering::Greater => other,
_ => self,
}
}
/// Returns the larger of two `Dt`s according to the total physical-time order
/// defined by [`Self::cmp`].
///
/// See [`Self::min`] for more details.
#[inline]
pub const fn max(self, other: Self) -> Self {
match self.cmp(other) {
Ordering::Less => other,
_ => self,
}
}
#[inline]
pub const fn eq(&self, other: &Self) -> bool {
match Dt::cmp(*self, *other) {
Ordering::Equal => true,
_ => false,
}
}
}
impl PartialEq for Dt {
#[inline]
fn eq(&self, other: &Self) -> bool {
Dt::eq(self, other)
}
}
impl Eq for Dt {}
impl PartialOrd for Dt {
#[inline]
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(Dt::cmp(*self, *other))
}
}
impl Ord for Dt {
#[inline]
fn cmp(&self, other: &Self) -> Ordering {
Dt::cmp(*self, *other)
}
}
impl core::hash::Hash for Dt {
/// Hashes the canonical TAI representation so that two `Dt`s that are
/// physically equal (after conversion) produce the same hash, regardless of
/// the original [`Scale`].
fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
self.sec.hash(state);
self.attos.hash(state);
}
}