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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
//! This module contains types and implementations for the Republic of China calendar.
//!
//! ```rust
//! use icu::calendar::{roc::Roc, Date, DateTime};
//!
//! // `Date` type
//! let date_iso = Date::try_new_iso_date(1970, 1, 2)
//! .expect("Failed to initialize ISO Date instance.");
//! let date_roc = Date::new_from_iso(date_iso, Roc);
//!
//! // `DateTime` type
//! let datetime_iso = DateTime::try_new_iso_datetime(1970, 1, 2, 13, 1, 0)
//! .expect("Failed to initialize ISO DateTime instance.");
//! let datetime_roc = DateTime::new_from_iso(datetime_iso, Roc);
//!
//! // `Date` checks
//! assert_eq!(date_roc.year().number, 59);
//! assert_eq!(date_roc.month().ordinal, 1);
//! assert_eq!(date_roc.day_of_month().0, 2);
//!
//! // `DateTime` checks
//! assert_eq!(datetime_roc.date.year().number, 59);
//! assert_eq!(datetime_roc.date.month().ordinal, 1);
//! assert_eq!(datetime_roc.date.day_of_month().0, 2);
//! assert_eq!(datetime_roc.time.hour.number(), 13);
//! assert_eq!(datetime_roc.time.minute.number(), 1);
//! assert_eq!(datetime_roc.time.second.number(), 0);
//! ```
use crate::{
calendar_arithmetic::ArithmeticDate, iso::IsoDateInner, types, AnyCalendarKind, Calendar,
CalendarError, Date, DateTime, Iso, Time,
};
use calendrical_calculations::helpers::i64_to_saturated_i32;
use tinystr::tinystr;
/// Year of the beginning of the Taiwanese (ROC/Minguo) calendar.
/// 1912 ISO = ROC 1
const ROC_ERA_OFFSET: i32 = 1911;
/// The Republic of China (ROC) Calendar
///
/// The [Republic of China calendar] is a solar calendar used in Taiwan and Penghu, as well as by overseas diaspora from
/// those locations. Months and days are identical to the [`Gregorian`] calendar, while years are counted
/// with 1912, the year of the establishment of the Republic of China, as year 1 of the ROC/Minguo/民国/民國 era.
///
///
/// The Republic of China calendar should not be confused with the Chinese traditional lunar calendar
/// (see [`Chinese`]).
///
/// # Era codes
///
/// This calendar supports two era codes: `"roc"`, corresponding to years in the 民國 (minguo) era (CE year 1912 and
/// after), and `"roc-inverse"`, corresponding to years before the 民國 (minguo) era (CE year 1911 and before).
///
///
/// # Month codes
///
/// This calendar supports 12 solar month codes (`"M01" - "M12"`)
///
/// [`Chinese`]: crate::chinese::Chinese
/// [`Gregorian`]: crate::Gregorian
#[derive(Copy, Clone, Debug, Default)]
#[allow(clippy::exhaustive_structs)] // this type is stable
pub struct Roc;
/// The inner date type used for representing [`Date`]s of [`Roc`]. See [`Date`] and [`Roc`] for more info.
#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq, PartialOrd, Ord)]
pub struct RocDateInner(IsoDateInner);
impl Calendar for Roc {
type DateInner = RocDateInner;
fn date_from_codes(
&self,
era: crate::types::Era,
year: i32,
month_code: crate::types::MonthCode,
day: u8,
) -> Result<Self::DateInner, crate::Error> {
let year = if era.0 == tinystr!(16, "roc") {
if year <= 0 {
return Err(CalendarError::OutOfRange);
}
year + ROC_ERA_OFFSET
} else if era.0 == tinystr!(16, "roc-inverse") {
if year <= 0 {
return Err(CalendarError::OutOfRange);
}
1 - year + ROC_ERA_OFFSET
} else {
return Err(CalendarError::UnknownEra(era.0, self.debug_name()));
};
ArithmeticDate::new_from_codes(self, year, month_code, day)
.map(IsoDateInner)
.map(RocDateInner)
}
fn date_from_iso(&self, iso: crate::Date<crate::Iso>) -> Self::DateInner {
RocDateInner(*iso.inner())
}
fn date_to_iso(&self, date: &Self::DateInner) -> crate::Date<crate::Iso> {
Date::from_raw(date.0, Iso)
}
fn months_in_year(&self, date: &Self::DateInner) -> u8 {
Iso.months_in_year(&date.0)
}
fn days_in_year(&self, date: &Self::DateInner) -> u16 {
Iso.days_in_year(&date.0)
}
fn days_in_month(&self, date: &Self::DateInner) -> u8 {
Iso.days_in_month(&date.0)
}
fn offset_date(&self, date: &mut Self::DateInner, offset: crate::DateDuration<Self>) {
Iso.offset_date(&mut date.0, offset.cast_unit())
}
fn until(
&self,
date1: &Self::DateInner,
date2: &Self::DateInner,
_calendar2: &Self,
largest_unit: crate::DateDurationUnit,
smallest_unit: crate::DateDurationUnit,
) -> crate::DateDuration<Self> {
Iso.until(&date1.0, &date2.0, &Iso, largest_unit, smallest_unit)
.cast_unit()
}
fn debug_name(&self) -> &'static str {
"ROC"
}
fn year(&self, date: &Self::DateInner) -> crate::types::FormattableYear {
year_as_roc(date.0 .0.year as i64)
}
fn is_in_leap_year(&self, date: &Self::DateInner) -> bool {
Iso.is_in_leap_year(&date.0)
}
fn month(&self, date: &Self::DateInner) -> crate::types::FormattableMonth {
Iso.month(&date.0)
}
fn day_of_month(&self, date: &Self::DateInner) -> crate::types::DayOfMonth {
Iso.day_of_month(&date.0)
}
fn day_of_year_info(&self, date: &Self::DateInner) -> crate::types::DayOfYearInfo {
let prev_year = date.0 .0.year.saturating_sub(1);
let next_year = date.0 .0.year.saturating_add(1);
types::DayOfYearInfo {
day_of_year: Iso::day_of_year(date.0),
days_in_year: Iso::days_in_year_direct(date.0 .0.year),
prev_year: year_as_roc(prev_year as i64),
days_in_prev_year: Iso::days_in_year_direct(prev_year),
next_year: year_as_roc(next_year as i64),
}
}
/// The [`AnyCalendarKind`] corresponding to this calendar
fn any_calendar_kind(&self) -> Option<AnyCalendarKind> {
Some(AnyCalendarKind::Roc)
}
}
impl Date<Roc> {
/// Construct a new Republic of China calendar Date.
///
/// Years are specified in the "roc" era. This function accepts an extended year in that era, so dates
/// before Minguo are negative and year 0 is 1 Before Minguo. To specify dates using explicit era
/// codes, use [`Roc::date_from_codes()`].
///
/// ```rust
/// use icu::calendar::Date;
/// use icu::calendar::gregorian::Gregorian;
/// use tinystr::tinystr;
///
/// // Create a new ROC Date
/// let date_roc = Date::try_new_roc_date(1, 2, 3)
/// .expect("Failed to initialize ROC Date instance.");
///
/// assert_eq!(date_roc.year().era.0, tinystr!(16, "roc"));
/// assert_eq!(date_roc.year().number, 1, "ROC year check failed!");
/// assert_eq!(date_roc.month().ordinal, 2, "ROC month check failed!");
/// assert_eq!(date_roc.day_of_month().0, 3, "ROC day of month check failed!");
///
/// // Convert to an equivalent Gregorian date
/// let date_gregorian = date_roc.to_calendar(Gregorian);
///
/// assert_eq!(date_gregorian.year().number, 1912, "Gregorian from ROC year check failed!");
/// assert_eq!(date_gregorian.month().ordinal, 2, "Gregorian from ROC month check failed!");
/// assert_eq!(date_gregorian.day_of_month().0, 3, "Gregorian from ROC day of month check failed!");
pub fn try_new_roc_date(year: i32, month: u8, day: u8) -> Result<Date<Roc>, CalendarError> {
let iso_year = year.saturating_add(ROC_ERA_OFFSET);
Date::try_new_iso_date(iso_year, month, day).map(|d| Date::new_from_iso(d, Roc))
}
}
impl DateTime<Roc> {
/// Construct a new Republic of China calendar datetime from integers.
///
/// Years are specified in the "roc" era, Before Minguo dates are negative (year 0 is 1 Before Minguo)
///
/// ```rust
/// use icu::calendar::DateTime;
/// use tinystr::tinystr;
///
/// // Create a new ROC DateTime
/// let datetime_roc = DateTime::try_new_roc_datetime(1, 2, 3, 13, 1, 0)
/// .expect("Failed to initialize ROC DateTime instance.");
///
/// assert_eq!(datetime_roc.date.year().era.0, tinystr!(16, "roc"));
/// assert_eq!(datetime_roc.date.year().number, 1, "ROC year check failed!");
/// assert_eq!(
/// datetime_roc.date.month().ordinal,
/// 2,
/// "ROC month check failed!"
/// );
/// assert_eq!(
/// datetime_roc.date.day_of_month().0,
/// 3,
/// "ROC day of month check failed!"
/// );
/// assert_eq!(datetime_roc.time.hour.number(), 13);
/// assert_eq!(datetime_roc.time.minute.number(), 1);
/// assert_eq!(datetime_roc.time.second.number(), 0);
/// ```
pub fn try_new_roc_datetime(
year: i32,
month: u8,
day: u8,
hour: u8,
minute: u8,
second: u8,
) -> Result<DateTime<Roc>, CalendarError> {
Ok(DateTime {
date: Date::try_new_roc_date(year, month, day)?,
time: Time::try_new(hour, minute, second, 0)?,
})
}
}
pub(crate) fn year_as_roc(year: i64) -> types::FormattableYear {
let year_i32 = i64_to_saturated_i32(year);
let offset_i64 = ROC_ERA_OFFSET as i64;
if year > offset_i64 {
types::FormattableYear {
era: types::Era(tinystr!(16, "roc")),
number: year_i32.saturating_sub(ROC_ERA_OFFSET),
cyclic: None,
related_iso: Some(year_i32),
}
} else {
types::FormattableYear {
era: types::Era(tinystr!(16, "roc-inverse")),
number: (ROC_ERA_OFFSET + 1).saturating_sub(year_i32),
cyclic: None,
related_iso: Some(year_i32),
}
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::types::Era;
use calendrical_calculations::rata_die::RataDie;
#[derive(Debug)]
struct TestCase {
fixed_date: RataDie,
iso_year: i32,
iso_month: u8,
iso_day: u8,
expected_year: i32,
expected_era: Era,
expected_month: u32,
expected_day: u32,
}
fn check_test_case(case: TestCase) {
let iso_from_fixed = Iso::iso_from_fixed(case.fixed_date);
let roc_from_fixed = Date::new_from_iso(iso_from_fixed, Roc);
assert_eq!(roc_from_fixed.year().number, case.expected_year,
"Failed year check from fixed: {case:?}\nISO: {iso_from_fixed:?}\nROC: {roc_from_fixed:?}");
assert_eq!(roc_from_fixed.year().era, case.expected_era,
"Failed era check from fixed: {case:?}\nISO: {iso_from_fixed:?}\nROC: {roc_from_fixed:?}");
assert_eq!(roc_from_fixed.month().ordinal, case.expected_month,
"Failed month check from fixed: {case:?}\nISO: {iso_from_fixed:?}\nROC: {roc_from_fixed:?}");
assert_eq!(roc_from_fixed.day_of_month().0, case.expected_day,
"Failed day_of_month check from fixed: {case:?}\nISO: {iso_from_fixed:?}\nROC: {roc_from_fixed:?}");
let iso_from_case = Date::try_new_iso_date(case.iso_year, case.iso_month, case.iso_day)
.expect("Failed to initialize ISO date for {case:?}");
let roc_from_case = Date::new_from_iso(iso_from_case, Roc);
assert_eq!(iso_from_fixed, iso_from_case,
"ISO from fixed not equal to ISO generated from manually-input ymd\nCase: {case:?}\nFixed: {iso_from_fixed:?}\nManual: {iso_from_case:?}");
assert_eq!(roc_from_fixed, roc_from_case,
"ROC date from fixed not equal to ROC generated from manually-input ymd\nCase: {case:?}\nFixed: {roc_from_fixed:?}\nManual: {roc_from_case:?}");
}
#[test]
fn test_roc_current_era() {
// Tests that the ROC calendar gives the correct expected day, month, and year for years >= 1912
// (years in the ROC/minguo era)
//
// Jan 1. 1912 CE = RD 697978
let cases = [
TestCase {
fixed_date: RataDie::new(697978),
iso_year: 1912,
iso_month: 1,
iso_day: 1,
expected_year: 1,
expected_era: Era(tinystr!(16, "roc")),
expected_month: 1,
expected_day: 1,
},
TestCase {
fixed_date: RataDie::new(698037),
iso_year: 1912,
iso_month: 2,
iso_day: 29,
expected_year: 1,
expected_era: Era(tinystr!(16, "roc")),
expected_month: 2,
expected_day: 29,
},
TestCase {
fixed_date: RataDie::new(698524),
iso_year: 1913,
iso_month: 6,
iso_day: 30,
expected_year: 2,
expected_era: Era(tinystr!(16, "roc")),
expected_month: 6,
expected_day: 30,
},
TestCase {
fixed_date: RataDie::new(738714),
iso_year: 2023,
iso_month: 7,
iso_day: 13,
expected_year: 112,
expected_era: Era(tinystr!(16, "roc")),
expected_month: 7,
expected_day: 13,
},
];
for case in cases {
check_test_case(case);
}
}
#[test]
fn test_roc_prior_era() {
// Tests that the ROC calendar gives the correct expected day, month, and year for years <= 1911
// (years in the ROC/minguo era)
//
// Jan 1. 1912 CE = RD 697978
let cases = [
TestCase {
fixed_date: RataDie::new(697977),
iso_year: 1911,
iso_month: 12,
iso_day: 31,
expected_year: 1,
expected_era: Era(tinystr!(16, "roc-inverse")),
expected_month: 12,
expected_day: 31,
},
TestCase {
fixed_date: RataDie::new(697613),
iso_year: 1911,
iso_month: 1,
iso_day: 1,
expected_year: 1,
expected_era: Era(tinystr!(16, "roc-inverse")),
expected_month: 1,
expected_day: 1,
},
TestCase {
fixed_date: RataDie::new(697612),
iso_year: 1910,
iso_month: 12,
iso_day: 31,
expected_year: 2,
expected_era: Era(tinystr!(16, "roc-inverse")),
expected_month: 12,
expected_day: 31,
},
TestCase {
fixed_date: RataDie::new(696576),
iso_year: 1908,
iso_month: 2,
iso_day: 29,
expected_year: 4,
expected_era: Era(tinystr!(16, "roc-inverse")),
expected_month: 2,
expected_day: 29,
},
TestCase {
fixed_date: RataDie::new(1),
iso_year: 1,
iso_month: 1,
iso_day: 1,
expected_year: 1911,
expected_era: Era(tinystr!(16, "roc-inverse")),
expected_month: 1,
expected_day: 1,
},
TestCase {
fixed_date: RataDie::new(0),
iso_year: 0,
iso_month: 12,
iso_day: 31,
expected_year: 1912,
expected_era: Era(tinystr!(16, "roc-inverse")),
expected_month: 12,
expected_day: 31,
},
];
for case in cases {
check_test_case(case);
}
}
#[test]
fn test_roc_directionality_near_epoch() {
// Tests that for a large range of fixed dates near the beginning of the minguo era (CE 1912),
// the comparison between those two fixed dates should be equal to the comparison between their
// corresponding YMD.
let rd_epoch_start = 697978;
for i in (rd_epoch_start - 100)..=(rd_epoch_start + 100) {
for j in (rd_epoch_start - 100)..=(rd_epoch_start + 100) {
let iso_i = Iso::iso_from_fixed(RataDie::new(i));
let iso_j = Iso::iso_from_fixed(RataDie::new(j));
let roc_i = iso_i.to_calendar(Roc);
let roc_j = iso_j.to_calendar(Roc);
assert_eq!(
i.cmp(&j),
iso_i.cmp(&iso_j),
"ISO directionality inconsistent with directionality for i: {i}, j: {j}"
);
assert_eq!(
i.cmp(&j),
roc_i.cmp(&roc_j),
"ROC directionality inconsistent with directionality for i: {i}, j: {j}"
);
}
}
}
#[test]
fn test_roc_directionality_near_rd_zero() {
// Same as `test_directionality_near_epoch`, but with a focus around RD 0
for i in -100..=100 {
for j in -100..100 {
let iso_i = Iso::iso_from_fixed(RataDie::new(i));
let iso_j = Iso::iso_from_fixed(RataDie::new(j));
let roc_i = iso_i.to_calendar(Roc);
let roc_j = iso_j.to_calendar(Roc);
assert_eq!(
i.cmp(&j),
iso_i.cmp(&iso_j),
"ISO directionality inconsistent with directionality for i: {i}, j: {j}"
);
assert_eq!(
i.cmp(&j),
roc_i.cmp(&roc_j),
"ROC directionality inconsistent with directionality for i: {i}, j: {j}"
);
}
}
}
}