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Implement LeapSecondsProvider
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‎Cargo.lock

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‎crates/lox-time/Cargo.toml

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@@ -7,6 +7,7 @@ license.workspace = true
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authors.workspace = true
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[dependencies]
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lox-io.workspace = true
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lox-utils.workspace = true
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lox-eop.workspace = true
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‎crates/lox-time/src/utc/leap_seconds.rs

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/*
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* Copyright (c) 2024. Helge Eichhorn and the LOX contributors
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, you can obtain one at https://mozilla.org/MPL/2.0/.
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*/
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use crate::calendar_dates::Date;
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use crate::constants::i64::{SECONDS_PER_DAY, SECONDS_PER_HALF_DAY};
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use lox_io::spice::{Kernel, KernelError};
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use std::fs::read_to_string;
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use std::num::ParseIntError;
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use std::path::Path;
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use thiserror::Error;
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use crate::deltas::TimeDelta;
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use crate::time_of_day::CivilTime;
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use crate::time_scales::Tai;
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use crate::utc::Utc;
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use crate::Time;
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const LEAP_SECONDS_KEY: &str = "DELTET/DELTA_AT";
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const LEAP_SECOND_EPOCHS_UTC: [i64; 28] = [
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-883656000, -867931200, -852033600, -820497600, -788961600, -757425600, -725803200, -694267200,
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-662731200, -631195200, -583934400, -552398400, -520862400, -457704000, -378734400, -315576000,
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-284040000, -236779200, -205243200, -173707200, -126273600, -79012800, -31579200, 189345600,
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284040000, 394372800, 488980800, 536500800,
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];
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const LEAP_SECOND_EPOCHS_TAI: [i64; 28] = [
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-883655991, -867931190, -852033589, -820497588, -788961587, -757425586, -725803185, -694267184,
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-662731183, -631195182, -583934381, -552398380, -520862379, -457703978, -378734377, -315575976,
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-284039975, -236779174, -205243173, -173707172, -126273571, -79012770, -31579169, 189345632,
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284040033, 394372834, 488980835, 536500836,
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];
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const LEAP_SECONDS: [i64; 28] = [
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10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
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34, 35, 36, 37,
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];
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pub trait LeapSecondsProvider {
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fn epochs_utc(&self) -> &[i64];
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fn epochs_tai(&self) -> &[i64];
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fn leap_seconds(&self) -> &[i64];
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fn find_leap_seconds(&self, epochs: &[i64], seconds: i64) -> Option<TimeDelta> {
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if seconds < epochs[0] {
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return None;
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}
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let idx = epochs.partition_point(|&epoch| epoch <= seconds) - 1;
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let seconds = self.leap_seconds()[idx];
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Some(TimeDelta::from_seconds(seconds))
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}
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fn delta_tai_utc(&self, tai: Time<Tai>) -> Option<TimeDelta> {
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self.find_leap_seconds(self.epochs_tai(), tai.seconds())
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}
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fn delta_utc_tai(&self, utc: Utc) -> Option<TimeDelta> {
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self.find_leap_seconds(self.epochs_utc(), utc.to_delta().seconds)
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.map(|mut ls| {
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if utc.second() == 60 {
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ls.seconds -= 1;
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}
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-ls
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})
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}
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}
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pub struct BuiltinLeapSeconds;
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impl LeapSecondsProvider for BuiltinLeapSeconds {
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fn epochs_utc(&self) -> &[i64] {
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&LEAP_SECOND_EPOCHS_UTC
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}
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fn epochs_tai(&self) -> &[i64] {
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&LEAP_SECOND_EPOCHS_TAI
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}
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fn leap_seconds(&self) -> &[i64] {
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&LEAP_SECONDS
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}
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}
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#[derive(Debug, Error)]
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pub enum LskError {
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#[error(transparent)]
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Io(#[from] std::io::Error),
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#[error(transparent)]
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Kernel(#[from] KernelError),
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#[error("no leap seconds found in kernel under key `{}`", LEAP_SECONDS_KEY)]
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NoLeapSeconds,
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#[error(transparent)]
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ParseInt(#[from] ParseIntError),
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}
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pub struct Lsk {
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epochs_utc: Vec<i64>,
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epochs_tai: Vec<i64>,
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leap_seconds: Vec<i64>,
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}
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impl Lsk {
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pub fn from_string(kernel: impl AsRef<str>) -> Result<Self, LskError> {
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let kernel = Kernel::from_string(kernel.as_ref())?;
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let data = kernel
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.get_timestamp_array(LEAP_SECONDS_KEY)
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.ok_or(LskError::NoLeapSeconds)?;
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let mut epochs_utc: Vec<i64> = vec![];
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let mut epochs_tai: Vec<i64> = vec![];
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let mut leap_seconds: Vec<i64> = vec![];
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data.chunks(2).for_each(|chunk| {
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if chunk.len() != 2 {
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return;
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}
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let ls = chunk[0].parse::<i64>();
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let date = Date::from_iso(
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&chunk[1]
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.replace("JAN", "01")
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.replace("JUL", "07")
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.replace("-1", "-01"),
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);
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if let (Ok(ls), Ok(date)) = (ls, date) {
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let epoch = date.j2000_day_number() * SECONDS_PER_DAY - SECONDS_PER_HALF_DAY;
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epochs_utc.push(epoch);
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epochs_tai.push(epoch + ls - 1);
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leap_seconds.push(ls);
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}
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});
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Ok(Self {
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epochs_utc,
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epochs_tai,
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leap_seconds,
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})
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}
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pub fn from_file(path: impl AsRef<Path>) -> Result<Self, LskError> {
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let path = path.as_ref();
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let kernel = read_to_string(path)?;
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Self::from_string(kernel)
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}
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}
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impl LeapSecondsProvider for Lsk {
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fn epochs_utc(&self) -> &[i64] {
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&self.epochs_utc
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}
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fn epochs_tai(&self) -> &[i64] {
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&self.epochs_tai
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}
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fn leap_seconds(&self) -> &[i64] {
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&self.leap_seconds
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use rstest::rstest;
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use std::sync::OnceLock;
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use crate::time;
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use crate::utc;
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#[rstest]
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#[case::j2000(Time::default(), Utc::default(), 32)]
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#[case::new_year_1972(time!(Tai, 1972, 1, 1, 0, 0, 10.0).unwrap(), utc!(1972, 1, 1).unwrap(), 10)]
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#[case::new_year_2017(time!(Tai, 2017, 1, 1, 0, 0, 37.0).unwrap(), utc!(2017, 1, 1, 0, 0, 0.0).unwrap(), 37)]
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#[case::new_year_2024(time!(Tai, 2024, 1, 1).unwrap(), utc!(2024, 1, 1).unwrap(), 37)]
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fn test_builtin_leap_seconds(#[case] tai: Time<Tai>, #[case] utc: Utc, #[case] expected: i64) {
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let ls_tai = BuiltinLeapSeconds.delta_tai_utc(tai).unwrap();
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let ls_utc = BuiltinLeapSeconds.delta_utc_tai(utc).unwrap();
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assert_eq!(ls_tai, TimeDelta::from_seconds(expected));
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assert_eq!(ls_utc, TimeDelta::from_seconds(-expected));
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}
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#[rstest]
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#[case::j2000(Time::default(), Utc::default(), 32)]
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#[case::new_year_1972(time!(Tai, 1972, 1, 1, 0, 0, 10.0).unwrap(), utc!(1972, 1, 1).unwrap(), 10)]
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#[case::new_year_2017(time!(Tai, 2017, 1, 1, 0, 0, 37.0).unwrap(), utc!(2017, 1, 1, 0, 0, 0.0).unwrap(), 37)]
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#[case::new_year_2024(time!(Tai, 2024, 1, 1).unwrap(), utc!(2024, 1, 1).unwrap(), 37)]
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fn test_lsk_leap_seconds(#[case] tai: Time<Tai>, #[case] utc: Utc, #[case] expected: i64) {
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let lsk = kernel();
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let ls_tai = lsk.delta_tai_utc(tai).unwrap();
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let ls_utc = lsk.delta_utc_tai(utc).unwrap();
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assert_eq!(ls_tai, TimeDelta::from_seconds(expected));
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assert_eq!(ls_utc, TimeDelta::from_seconds(-expected));
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}
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#[test]
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fn test_lsk() {
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let lsk = kernel();
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assert_eq!(lsk.epochs_utc().len(), 28);
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assert_eq!(lsk.epochs_tai().len(), 28);
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assert_eq!(lsk.leap_seconds().len(), 28);
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assert_eq!(lsk.epochs_utc(), &LEAP_SECOND_EPOCHS_UTC);
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assert_eq!(lsk.epochs_tai(), &LEAP_SECOND_EPOCHS_TAI);
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}
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const KERNEL: &str = "KPL/LSK
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\\begindata
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DELTET/DELTA_AT = ( 10, @1972-JAN-1
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11, @1972-JUL-1
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12, @1973-JAN-1
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13, @1974-JAN-1
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14, @1975-JAN-1
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15, @1976-JAN-1
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16, @1977-JAN-1
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17, @1978-JAN-1
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18, @1979-JAN-1
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19, @1980-JAN-1
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20, @1981-JUL-1
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21, @1982-JUL-1
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22, @1983-JUL-1
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23, @1985-JUL-1
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24, @1988-JAN-1
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25, @1990-JAN-1
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26, @1991-JAN-1
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27, @1992-JUL-1
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28, @1993-JUL-1
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29, @1994-JUL-1
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30, @1996-JAN-1
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31, @1997-JUL-1
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32, @1999-JAN-1
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33, @2006-JAN-1
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34, @2009-JAN-1
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35, @2012-JUL-1
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36, @2015-JUL-1
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37, @2017-JAN-1 )
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\\begintext";
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fn kernel() -> &'static Lsk {
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static LSK: OnceLock<Lsk> = OnceLock::new();
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LSK.get_or_init(|| Lsk::from_string(KERNEL).expect("file should be parsable"))
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}
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}

‎crates/lox-time/src/utc/transformations/from1972.rs

Lines changed: 4 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -19,8 +19,8 @@ use lox_utils::slices::is_sorted_asc;
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use crate::calendar_dates::Date;
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use crate::deltas::TimeDelta;
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use crate::julian_dates::JulianDate;
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use crate::time_of_day::CivilTime;
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use crate::time_scales::Tai;
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use crate::utc::leap_seconds::{BuiltinLeapSeconds, LeapSecondsProvider};
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use crate::utc::Utc;
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use crate::Time;
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@@ -33,7 +33,7 @@ const MJD_LEAP_SECOND_EPOCHS: [u64; 28] = [
3333

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impl Date {
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pub fn is_leap_second_date(&self) -> bool {
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let mjd = (self.days_since_modified_julian_epoch().ceil()).to_u64();
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let mjd = (self.days_since_modified_julian_epoch() + 1.0).to_u64();
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if let Some(mjd) = mjd {
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return MJD_LEAP_SECOND_EPOCHS.contains(&mjd);
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}
@@ -82,39 +82,12 @@ pub const LEAP_SECONDS: [i64; 28] = [
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/// For dates from 1972-01-01, returns a [TimeDelta] representing the count of leap seconds between
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/// TAI and UTC. Returns `None` for dates before 1972.
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pub fn delta_tai_utc(tai: Time<Tai>) -> Option<TimeDelta> {
85-
j2000_tai_leap_second_epochs()
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.iter()
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.rev()
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.zip(LEAP_SECONDS.iter().rev())
89-
.find_map(|(&epoch, &leap_seconds)| {
90-
if epoch <= tai.seconds() {
91-
Some(TimeDelta::from_seconds(leap_seconds))
92-
} else {
93-
None
94-
}
95-
})
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BuiltinLeapSeconds.delta_tai_utc(tai)
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}
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/// UTC minus TAI. Calculates the correct leap second count for dates after 1972 by simple lookup.
9989
pub fn delta_utc_tai(utc: Utc) -> Option<TimeDelta> {
100-
let base_time = utc.to_delta();
101-
j2000_utc_leap_second_epochs()
102-
.iter()
103-
.rev()
104-
.zip(LEAP_SECONDS.iter().rev())
105-
.find_map(|(&epoch, &leap_seconds)| {
106-
if epoch <= base_time.seconds {
107-
Some(TimeDelta::from_seconds(leap_seconds))
108-
} else {
109-
None
110-
}
111-
})
112-
.map(|mut delta| {
113-
if utc.second() == 60 {
114-
delta.seconds -= 1;
115-
}
116-
-delta
117-
})
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BuiltinLeapSeconds.delta_utc_tai(utc)
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}
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impl Time<Tai> {

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