firefox-main/third_party/rust/icu_calendar/src/cal/iso.rs

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// This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
use crate::cal::abstract_gregorian::{impl_with_abstract_gregorian, GregorianYears};
use crate::calendar_arithmetic::ArithmeticDate;
use crate::error::UnknownEraError;
use crate::{types, Date, DateError, RangeError};
use tinystr::tinystr;
/// The [ISO-8601 Calendar](https://en.wikipedia.org/wiki/ISO_8601#Dates)
///
/// This calendar is identical to the [`Gregorian`](super::Gregorian) calendar,
/// except that it uses a single `default` era instead of `bce` and `ce`.
///
/// This corresponds to the `"iso8601"` [CLDR calendar](https://unicode.org/reports/tr35/#UnicodeCalendarIdentifier).
///
/// # Era codes
///
/// This calendar uses a single era: `default`
#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[allow(clippy::exhaustive_structs)] // this type is stable
pub struct Iso;
impl_with_abstract_gregorian!(crate::cal::Iso, IsoDateInner, IsoEra, _x, IsoEra);
#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub(crate) struct IsoEra;
impl GregorianYears for IsoEra {
fn extended_from_era_year(
&self,
era: Option<&[u8]>,
year: i32,
) -> Result<i32, UnknownEraError> {
match era {
Some(b"default") | None => Ok(year),
Some(_) => Err(UnknownEraError),
}
}
fn era_year_from_extended(&self, extended_year: i32, _month: u8, _day: u8) -> types::EraYear {
types::EraYear {
era_index: Some(0),
era: tinystr!(16, "default"),
year: extended_year,
extended_year,
ambiguity: types::YearAmbiguity::Unambiguous,
}
}
fn debug_name(&self) -> &'static str {
"ISO"
}
}
impl Date<Iso> {
/// Construct a new ISO date from integers.
///
/// ```rust
/// use icu::calendar::Date;
///
/// let date_iso = Date::try_new_iso(1970, 1, 2)
/// .expect("Failed to initialize ISO Date instance.");
///
/// assert_eq!(date_iso.era_year().year, 1970);
/// assert_eq!(date_iso.month().ordinal, 1);
/// assert_eq!(date_iso.day_of_month().0, 2);
/// ```
pub fn try_new_iso(year: i32, month: u8, day: u8) -> Result<Date<Iso>, RangeError> {
ArithmeticDate::new_gregorian::<IsoEra>(year, month, day)
.map(IsoDateInner)
.map(|i| Date::from_raw(i, Iso))
}
}
impl Iso {
/// Construct a new ISO Calendar
pub fn new() -> Self {
Self
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::types::{DateDuration, RataDie, Weekday};
use crate::Calendar;
#[test]
fn iso_overflow() {
#[derive(Debug)]
struct TestCase {
year: i32,
month: u8,
day: u8,
rd: RataDie,
saturating: bool,
}
// Calculates the max possible year representable using i32::MAX as the RD
let max_year = Iso.from_rata_die(RataDie::new(i32::MAX as i64)).0.year;
// Calculates the minimum possible year representable using i32::MIN as the RD
// *Cannot be tested yet due to hard coded date not being available yet (see line 436)
let min_year = -5879610;
let cases = [
TestCase {
// Earliest date that can be represented before causing a minimum overflow
year: min_year,
month: 6,
day: 22,
rd: RataDie::new(i32::MIN as i64),
saturating: false,
},
TestCase {
year: min_year,
month: 6,
day: 23,
rd: RataDie::new(i32::MIN as i64 + 1),
saturating: false,
},
TestCase {
year: min_year,
month: 6,
day: 21,
rd: RataDie::new(i32::MIN as i64 - 1),
saturating: false,
},
TestCase {
year: min_year,
month: 12,
day: 31,
rd: RataDie::new(-2147483456),
saturating: false,
},
TestCase {
year: min_year + 1,
month: 1,
day: 1,
rd: RataDie::new(-2147483455),
saturating: false,
},
TestCase {
year: max_year,
month: 6,
day: 11,
rd: RataDie::new(i32::MAX as i64 - 30),
saturating: false,
},
TestCase {
year: max_year,
month: 7,
day: 9,
rd: RataDie::new(i32::MAX as i64 - 2),
saturating: false,
},
TestCase {
year: max_year,
month: 7,
day: 10,
rd: RataDie::new(i32::MAX as i64 - 1),
saturating: false,
},
TestCase {
// Latest date that can be represented before causing a maximum overflow
year: max_year,
month: 7,
day: 11,
rd: RataDie::new(i32::MAX as i64),
saturating: false,
},
TestCase {
year: max_year,
month: 7,
day: 12,
rd: RataDie::new(i32::MAX as i64 + 1),
saturating: false,
},
TestCase {
year: i32::MIN,
month: 1,
day: 2,
rd: RataDie::new(-784352296669),
saturating: false,
},
TestCase {
year: i32::MIN,
month: 1,
day: 1,
rd: RataDie::new(-784352296670),
saturating: false,
},
TestCase {
year: i32::MIN,
month: 1,
day: 1,
rd: RataDie::new(-784352296671),
saturating: true,
},
TestCase {
year: i32::MAX,
month: 12,
day: 30,
rd: RataDie::new(784352295938),
saturating: false,
},
TestCase {
year: i32::MAX,
month: 12,
day: 31,
rd: RataDie::new(784352295939),
saturating: false,
},
TestCase {
year: i32::MAX,
month: 12,
day: 31,
rd: RataDie::new(784352295940),
saturating: true,
},
];
for case in cases {
let date = Date::try_new_iso(case.year, case.month, case.day).unwrap();
if !case.saturating {
assert_eq!(date.to_rata_die(), case.rd, "{case:?}");
}
assert_eq!(Date::from_rata_die(case.rd, Iso), date, "{case:?}");
}
}
// Calculates the minimum possible year representable using a large negative fixed date
#[test]
fn min_year() {
assert_eq!(
Date::from_rata_die(RataDie::big_negative(), Iso)
.year()
.era()
.unwrap()
.year,
i32::MIN
);
}
#[test]
fn test_day_of_week() {
// June 23, 2021 is a Wednesday
assert_eq!(
Date::try_new_iso(2021, 6, 23).unwrap().day_of_week(),
Weekday::Wednesday,
);
// Feb 2, 1983 was a Wednesday
assert_eq!(
Date::try_new_iso(1983, 2, 2).unwrap().day_of_week(),
Weekday::Wednesday,
);
// Jan 21, 2021 was a Tuesday
assert_eq!(
Date::try_new_iso(2020, 1, 21).unwrap().day_of_week(),
Weekday::Tuesday,
);
}
#[test]
fn test_day_of_year() {
// June 23, 2021 was day 174
assert_eq!(Date::try_new_iso(2021, 6, 23).unwrap().day_of_year().0, 174,);
// June 23, 2020 was day 175
assert_eq!(Date::try_new_iso(2020, 6, 23).unwrap().day_of_year().0, 175,);
// Feb 2, 1983 was a Wednesday
assert_eq!(Date::try_new_iso(1983, 2, 2).unwrap().day_of_year().0, 33,);
}
#[test]
fn test_offset() {
let today = Date::try_new_iso(2021, 6, 23).unwrap();
let today_plus_5000 = Date::try_new_iso(2035, 3, 2).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_days(5000), Default::default())
.unwrap();
assert_eq!(offset, today_plus_5000);
let today = Date::try_new_iso(2021, 6, 23).unwrap();
let today_minus_5000 = Date::try_new_iso(2007, 10, 15).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_days(-5000), Default::default())
.unwrap();
assert_eq!(offset, today_minus_5000);
}
#[test]
fn test_offset_at_month_boundary() {
let today = Date::try_new_iso(2020, 2, 28).unwrap();
let today_plus_2 = Date::try_new_iso(2020, 3, 1).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_days(2), Default::default())
.unwrap();
assert_eq!(offset, today_plus_2);
let today = Date::try_new_iso(2020, 2, 28).unwrap();
let today_plus_3 = Date::try_new_iso(2020, 3, 2).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_days(3), Default::default())
.unwrap();
assert_eq!(offset, today_plus_3);
let today = Date::try_new_iso(2020, 2, 28).unwrap();
let today_plus_1 = Date::try_new_iso(2020, 2, 29).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_days(1), Default::default())
.unwrap();
assert_eq!(offset, today_plus_1);
let today = Date::try_new_iso(2019, 2, 28).unwrap();
let today_plus_2 = Date::try_new_iso(2019, 3, 2).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_days(2), Default::default())
.unwrap();
assert_eq!(offset, today_plus_2);
let today = Date::try_new_iso(2019, 2, 28).unwrap();
let today_plus_1 = Date::try_new_iso(2019, 3, 1).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_days(1), Default::default())
.unwrap();
assert_eq!(offset, today_plus_1);
let today = Date::try_new_iso(2020, 3, 1).unwrap();
let today_minus_1 = Date::try_new_iso(2020, 2, 29).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_days(-1), Default::default())
.unwrap();
assert_eq!(offset, today_minus_1);
}
#[test]
fn test_offset_handles_negative_month_offset() {
let today = Date::try_new_iso(2020, 3, 1).unwrap();
let today_minus_2_months = Date::try_new_iso(2020, 1, 1).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_months(-2), Default::default())
.unwrap();
assert_eq!(offset, today_minus_2_months);
let today = Date::try_new_iso(2020, 3, 1).unwrap();
let today_minus_4_months = Date::try_new_iso(2019, 11, 1).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_months(-4), Default::default())
.unwrap();
assert_eq!(offset, today_minus_4_months);
let today = Date::try_new_iso(2020, 3, 1).unwrap();
let today_minus_24_months = Date::try_new_iso(2018, 3, 1).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_months(-24), Default::default())
.unwrap();
assert_eq!(offset, today_minus_24_months);
let today = Date::try_new_iso(2020, 3, 1).unwrap();
let today_minus_27_months = Date::try_new_iso(2017, 12, 1).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_months(-27), Default::default())
.unwrap();
assert_eq!(offset, today_minus_27_months);
}
#[test]
fn test_offset_handles_out_of_bound_month_offset() {
let today = Date::try_new_iso(2021, 1, 31).unwrap();
// since 2021/02/31 isn't a valid date, `offset_date` auto-adjusts by constraining to the last day in February
let today_plus_1_month = Date::try_new_iso(2021, 2, 28).unwrap();
let offset = today
.try_added_with_options(DateDuration::for_months(1), Default::default())
.unwrap();
assert_eq!(offset, today_plus_1_month);
let today = Date::try_new_iso(2021, 1, 31).unwrap();
// since 2021/02/31 isn't a valid date, `offset_date` auto-adjusts by constraining to the last day in February
// and then adding the days
let today_plus_1_month_1_day = Date::try_new_iso(2021, 3, 1).unwrap();
let offset = today
.try_added_with_options(
DateDuration {
months: 1,
days: 1,
..Default::default()
},
Default::default(),
)
.unwrap();
assert_eq!(offset, today_plus_1_month_1_day);
}
#[test]
fn test_iso_to_from_rd() {
// Reminder: ISO year 0 is Gregorian year 1 BCE.
// Year 0 is a leap year due to the 400-year rule.
fn check(rd: i64, year: i32, month: u8, day: u8) {
let rd = RataDie::new(rd);
assert_eq!(
Date::from_rata_die(rd, Iso),
Date::try_new_iso(year, month, day).unwrap(),
"RD: {rd:?}"
);
}
check(-1828, -5, 12, 30);
check(-1827, -5, 12, 31); // leap year
check(-1826, -4, 1, 1);
check(-1462, -4, 12, 30);
check(-1461, -4, 12, 31);
check(-1460, -3, 1, 1);
check(-1459, -3, 1, 2);
check(-732, -2, 12, 30);
check(-731, -2, 12, 31);
check(-730, -1, 1, 1);
check(-367, -1, 12, 30);
check(-366, -1, 12, 31);
check(-365, 0, 1, 1); // leap year
check(-364, 0, 1, 2);
check(-1, 0, 12, 30);
check(0, 0, 12, 31);
check(1, 1, 1, 1);
check(2, 1, 1, 2);
check(364, 1, 12, 30);
check(365, 1, 12, 31);
check(366, 2, 1, 1);
check(1459, 4, 12, 29);
check(1460, 4, 12, 30);
check(1461, 4, 12, 31); // leap year
check(1462, 5, 1, 1);
}
}