esbat/
conv.rs

1// Copyright (c) 2020 iliana destroyer of worlds <iliana@buttslol.net>
2// SPDX-License-Identifier: CC-BY-NC-4.0
3//
4// This work is licensed under the Creative Commons Attribution-NonCommercial 4.0 International
5// License. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc/4.0/
6// or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
7
8use crate::calendar::{fixed_from_gregorian, gregorian_from_fixed};
9use crate::util::u32;
10use chrono::{DateTime, Datelike, TimeZone, Timelike, Utc};
11
12pub(crate) fn fixed_from_chrono(t: DateTime<Utc>) -> f64 {
13    let rd_sec = f64::from(t.hour() * 3600 + t.minute() * 60 + t.second())
14        + (f64::from(t.nanosecond()) / 1_000_000_000.0);
15    f64::from(fixed_from_gregorian(t.year(), t.month(), t.day())) + (rd_sec / 86400.0)
16}
17
18pub(crate) fn chrono_from_fixed(t: f64) -> Option<DateTime<Utc>> {
19    let (year, month, day) = gregorian_from_fixed(t);
20    let fract = t.rem_euclid(1.0) * 86400.0;
21    let hour = u32(fract / 3600.0);
22    let min = u32(fract % 3600.0 / 60.0);
23    let sec = u32(fract % 60.0);
24    let nano = u32((fract % 1.0) * 1_000_000_000.0);
25    Utc.ymd_opt(year, month, day).and_hms_nano_opt(hour, min, sec, nano).single()
26}
27
28#[cfg(test)]
29#[allow(clippy::float_cmp)]
30#[test]
31fn test_chrono_conversions() {
32    let input = [
33        (730_120.5, Utc.ymd(2000, 1, 1).and_hms(12, 0, 0)),
34        (-61_387.0 + 256_f64.recip(), Utc.ymd(-168, 12, 5).and_hms_milli(0, 5, 37, 500)),
35        (-95_746_495.0, chrono::MIN_DATE.and_hms(0, 0, 0)),
36        (95_745_764.0, chrono::MAX_DATE.and_hms(0, 0, 0)),
37    ];
38    let iter = crate::data::TEST_DATA
39        .iter()
40        .copied()
41        .map(|(rd, (y, m, d), _, _, _, _)| (rd, Utc.ymd(y, m, d).and_hms(0, 0, 0)))
42        .chain(input.iter().copied());
43    for (rd, datetime) in iter {
44        assert_eq!(rd, fixed_from_chrono(datetime));
45        assert_eq!(chrono_from_fixed(rd).unwrap(), datetime);
46    }
47
48    assert!(chrono_from_fixed(-95_746_496.0).is_none());
49    assert!(chrono_from_fixed(95_745_765.0).is_none());
50}
esbat/conv.rs

esbat/
conv.rs
