deep-time 0.1.0-alpha.2

High-precision time types, time scale conversions, relativistic time, and a flexible date and duration parser
Documentation 
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use crate::{Scale, Dt};
use hifitime::Epoch;

impl Dt {
    /// Creates a `Dt` from a `hifitime::Epoch`.
    ///
    /// The conversion is exact (within hifitime's nanosecond precision).
    /// Uses a runtime-computed offset so it always matches whatever
    /// calendar math hifitime uses (including negative years).
    pub fn from_hifitime_epoch(epoch: Epoch) -> Self {
        let ns_since_j1900 = epoch.to_tai_duration().total_nanoseconds();

        let j1900 = Epoch::from_gregorian_tai(1900, 1, 1, 12, 0, 0, 0);
        let j2000 = Epoch::from_gregorian_tai(2000, 1, 1, 12, 0, 0, 0);
        let offset_ns = j2000.to_tai_duration().total_nanoseconds()
            - j1900.to_tai_duration().total_nanoseconds();

        let ns_since_zero_tai = ns_since_j1900 - offset_ns;
        Self::from_ns(ns_since_zero_tai, Scale::TAI)
    }
}