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// This is a part of Chrono. // See README.md and LICENSE.txt for details. //! ISO 8601 week. use core::fmt; use super::internals::{DateImpl, Of, YearFlags}; /// ISO 8601 week. /// /// This type, combined with [`Weekday`](../enum.Weekday.html), /// constitues the ISO 8601 [week date](./struct.NaiveDate.html#week-date). /// One can retrieve this type from the existing [`Datelike`](../trait.Datelike.html) types /// via the [`Datelike::iso_week`](../trait.Datelike.html#tymethod.iso_week) method. #[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone)] pub struct IsoWeek { // note that this allows for larger year range than `NaiveDate`. // this is crucial because we have an edge case for the first and last week supported, // which year number might not match the calendar year number. ywf: DateImpl, // (year << 10) | (week << 4) | flag } /// Returns the corresponding `IsoWeek` from the year and the `Of` internal value. // // internal use only. we don't expose the public constructor for `IsoWeek` for now, // because the year range for the week date and the calendar date do not match and // it is confusing to have a date that is out of range in one and not in another. // currently we sidestep this issue by making `IsoWeek` fully dependent of `Datelike`. pub fn iso_week_from_yof(year: i32, of: Of) -> IsoWeek { let (rawweek, _) = of.isoweekdate_raw(); let (year, week) = if rawweek < 1 { // previous year let prevlastweek = YearFlags::from_year(year - 1).nisoweeks(); (year - 1, prevlastweek) } else { let lastweek = of.flags().nisoweeks(); if rawweek > lastweek { // next year (year + 1, 1) } else { (year, rawweek) } }; IsoWeek { ywf: (year << 10) | (week << 4) as DateImpl | DateImpl::from(of.flags().0) } } impl IsoWeek { /// Returns the year number for this ISO week. /// /// # Example /// /// ~~~~ /// use chrono::{NaiveDate, Datelike, Weekday}; /// /// let d = NaiveDate::from_isoywd(2015, 1, Weekday::Mon); /// assert_eq!(d.iso_week().year(), 2015); /// ~~~~ /// /// This year number might not match the calendar year number. /// Continuing the example... /// /// ~~~~ /// # use chrono::{NaiveDate, Datelike, Weekday}; /// # let d = NaiveDate::from_isoywd(2015, 1, Weekday::Mon); /// assert_eq!(d.year(), 2014); /// assert_eq!(d, NaiveDate::from_ymd(2014, 12, 29)); /// ~~~~ #[inline] pub fn year(&self) -> i32 { self.ywf >> 10 } /// Returns the ISO week number starting from 1. /// /// The return value ranges from 1 to 53. (The last week of year differs by years.) /// /// # Example /// /// ~~~~ /// use chrono::{NaiveDate, Datelike, Weekday}; /// /// let d = NaiveDate::from_isoywd(2015, 15, Weekday::Mon); /// assert_eq!(d.iso_week().week(), 15); /// ~~~~ #[inline] pub fn week(&self) -> u32 { ((self.ywf >> 4) & 0x3f) as u32 } /// Returns the ISO week number starting from 0. /// /// The return value ranges from 0 to 52. (The last week of year differs by years.) /// /// # Example /// /// ~~~~ /// use chrono::{NaiveDate, Datelike, Weekday}; /// /// let d = NaiveDate::from_isoywd(2015, 15, Weekday::Mon); /// assert_eq!(d.iso_week().week0(), 14); /// ~~~~ #[inline] pub fn week0(&self) -> u32 { ((self.ywf >> 4) & 0x3f) as u32 - 1 } } /// The `Debug` output of the ISO week `w` is the same as /// [`d.format("%G-W%V")`](../format/strftime/index.html) /// where `d` is any `NaiveDate` value in that week. /// /// # Example /// /// ~~~~ /// use chrono::{NaiveDate, Datelike}; /// /// assert_eq!(format!("{:?}", NaiveDate::from_ymd(2015, 9, 5).iso_week()), "2015-W36"); /// assert_eq!(format!("{:?}", NaiveDate::from_ymd( 0, 1, 3).iso_week()), "0000-W01"); /// assert_eq!(format!("{:?}", NaiveDate::from_ymd(9999, 12, 31).iso_week()), "9999-W52"); /// ~~~~ /// /// ISO 8601 requires an explicit sign for years before 1 BCE or after 9999 CE. /// /// ~~~~ /// # use chrono::{NaiveDate, Datelike}; /// assert_eq!(format!("{:?}", NaiveDate::from_ymd( 0, 1, 2).iso_week()), "-0001-W52"); /// assert_eq!(format!("{:?}", NaiveDate::from_ymd(10000, 12, 31).iso_week()), "+10000-W52"); /// ~~~~ impl fmt::Debug for IsoWeek { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { let year = self.year(); let week = self.week(); if 0 <= year && year <= 9999 { write!(f, "{:04}-W{:02}", year, week) } else { // ISO 8601 requires the explicit sign for out-of-range years write!(f, "{:+05}-W{:02}", year, week) } } } #[cfg(test)] mod tests { use naive::{internals, MAX_DATE, MIN_DATE}; use Datelike; #[test] fn test_iso_week_extremes() { let minweek = MIN_DATE.iso_week(); let maxweek = MAX_DATE.iso_week(); assert_eq!(minweek.year(), internals::MIN_YEAR); assert_eq!(minweek.week(), 1); assert_eq!(minweek.week0(), 0); assert_eq!(format!("{:?}", minweek), MIN_DATE.format("%G-W%V").to_string()); assert_eq!(maxweek.year(), internals::MAX_YEAR + 1); assert_eq!(maxweek.week(), 1); assert_eq!(maxweek.week0(), 0); assert_eq!(format!("{:?}", maxweek), MAX_DATE.format("%G-W%V").to_string()); } }