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Diffstat (limited to 'third_party/rust/time/src/date.rs')
| -rw-r--r-- | third_party/rust/time/src/date.rs | 1050 |
1 files changed, 1050 insertions, 0 deletions
diff --git a/third_party/rust/time/src/date.rs b/third_party/rust/time/src/date.rs new file mode 100644 index 0000000000..b3023e0c05 --- /dev/null +++ b/third_party/rust/time/src/date.rs @@ -0,0 +1,1050 @@ +//! The [`Date`] struct and its associated `impl`s. + +use core::fmt; +use core::ops::{Add, Sub}; +use core::time::Duration as StdDuration; +#[cfg(feature = "formatting")] +use std::io; + +#[cfg(feature = "formatting")] +use crate::formatting::Formattable; +#[cfg(feature = "parsing")] +use crate::parsing::Parsable; +use crate::util::{days_in_year, days_in_year_month, is_leap_year, weeks_in_year}; +use crate::{error, Duration, Month, PrimitiveDateTime, Time, Weekday}; + +/// The minimum valid year. +pub(crate) const MIN_YEAR: i32 = if cfg!(feature = "large-dates") { + -999_999 +} else { + -9999 +}; +/// The maximum valid year. +pub(crate) const MAX_YEAR: i32 = if cfg!(feature = "large-dates") { + 999_999 +} else { + 9999 +}; + +/// Date in the proleptic Gregorian calendar. +/// +/// By default, years between ±9999 inclusive are representable. This can be expanded to ±999,999 +/// inclusive by enabling the `large-dates` crate feature. Doing so has performance implications +/// and introduces some ambiguities when parsing. +#[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)] +pub struct Date { + /// Bitpacked field containing both the year and ordinal. + // | xx | xxxxxxxxxxxxxxxxxxxxx | xxxxxxxxx | + // | 2 bits | 21 bits | 9 bits | + // | unassigned | year | ordinal | + // The year is 15 bits when `large-dates` is not enabled. + value: i32, +} + +impl Date { + /// The minimum valid `Date`. + /// + /// The value of this may vary depending on the feature flags enabled. + pub const MIN: Self = Self::__from_ordinal_date_unchecked(MIN_YEAR, 1); + + /// The maximum valid `Date`. + /// + /// The value of this may vary depending on the feature flags enabled. + pub const MAX: Self = Self::__from_ordinal_date_unchecked(MAX_YEAR, days_in_year(MAX_YEAR)); + + // region: constructors + /// Construct a `Date` from the year and ordinal values, the validity of which must be + /// guaranteed by the caller. + #[doc(hidden)] + pub const fn __from_ordinal_date_unchecked(year: i32, ordinal: u16) -> Self { + debug_assert!(year >= MIN_YEAR); + debug_assert!(year <= MAX_YEAR); + debug_assert!(ordinal != 0); + debug_assert!(ordinal <= days_in_year(year)); + + Self { + value: (year << 9) | ordinal as i32, + } + } + + /// Attempt to create a `Date` from the year, month, and day. + /// + /// ```rust + /// # use time::{Date, Month}; + /// assert!(Date::from_calendar_date(2019, Month::January, 1).is_ok()); + /// assert!(Date::from_calendar_date(2019, Month::December, 31).is_ok()); + /// ``` + /// + /// ```rust + /// # use time::{Date, Month}; + /// assert!(Date::from_calendar_date(2019, Month::February, 29).is_err()); // 2019 isn't a leap year. + /// ``` + pub const fn from_calendar_date( + year: i32, + month: Month, + day: u8, + ) -> Result<Self, error::ComponentRange> { + /// Cumulative days through the beginning of a month in both common and leap years. + const DAYS_CUMULATIVE_COMMON_LEAP: [[u16; 12]; 2] = [ + [0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334], + [0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335], + ]; + + ensure_value_in_range!(year in MIN_YEAR => MAX_YEAR); + ensure_value_in_range!(day conditionally in 1 => days_in_year_month(year, month)); + + Ok(Self::__from_ordinal_date_unchecked( + year, + DAYS_CUMULATIVE_COMMON_LEAP[is_leap_year(year) as usize][month as usize - 1] + + day as u16, + )) + } + + /// Attempt to create a `Date` from the year and ordinal day number. + /// + /// ```rust + /// # use time::Date; + /// assert!(Date::from_ordinal_date(2019, 1).is_ok()); + /// assert!(Date::from_ordinal_date(2019, 365).is_ok()); + /// ``` + /// + /// ```rust + /// # use time::Date; + /// assert!(Date::from_ordinal_date(2019, 366).is_err()); // 2019 isn't a leap year. + /// ``` + pub const fn from_ordinal_date(year: i32, ordinal: u16) -> Result<Self, error::ComponentRange> { + ensure_value_in_range!(year in MIN_YEAR => MAX_YEAR); + ensure_value_in_range!(ordinal conditionally in 1 => days_in_year(year)); + Ok(Self::__from_ordinal_date_unchecked(year, ordinal)) + } + + /// Attempt to create a `Date` from the ISO year, week, and weekday. + /// + /// ```rust + /// # use time::{Date, Weekday::*}; + /// assert!(Date::from_iso_week_date(2019, 1, Monday).is_ok()); + /// assert!(Date::from_iso_week_date(2019, 1, Tuesday).is_ok()); + /// assert!(Date::from_iso_week_date(2020, 53, Friday).is_ok()); + /// ``` + /// + /// ```rust + /// # use time::{Date, Weekday::*}; + /// assert!(Date::from_iso_week_date(2019, 53, Monday).is_err()); // 2019 doesn't have 53 weeks. + /// ``` + pub const fn from_iso_week_date( + year: i32, + week: u8, + weekday: Weekday, + ) -> Result<Self, error::ComponentRange> { + ensure_value_in_range!(year in MIN_YEAR => MAX_YEAR); + ensure_value_in_range!(week conditionally in 1 => weeks_in_year(year)); + + let adj_year = year - 1; + let raw = 365 * adj_year + div_floor!(adj_year, 4) - div_floor!(adj_year, 100) + + div_floor!(adj_year, 400); + let jan_4 = match (raw % 7) as i8 { + -6 | 1 => 8, + -5 | 2 => 9, + -4 | 3 => 10, + -3 | 4 => 4, + -2 | 5 => 5, + -1 | 6 => 6, + _ => 7, + }; + let ordinal = week as i16 * 7 + weekday.number_from_monday() as i16 - jan_4; + + Ok(if ordinal <= 0 { + Self::__from_ordinal_date_unchecked( + year - 1, + (ordinal as u16).wrapping_add(days_in_year(year - 1)), + ) + } else if ordinal > days_in_year(year) as i16 { + Self::__from_ordinal_date_unchecked(year + 1, ordinal as u16 - days_in_year(year)) + } else { + Self::__from_ordinal_date_unchecked(year, ordinal as _) + }) + } + + /// Create a `Date` from the Julian day. + /// + /// The algorithm to perform this conversion is derived from one provided by Peter Baum; it is + /// freely available [here](https://www.researchgate.net/publication/316558298_Date_Algorithms). + /// + /// ```rust + /// # use time::Date; + /// # use time_macros::date; + /// assert_eq!(Date::from_julian_day(0), Ok(date!(-4713 - 11 - 24))); + /// assert_eq!(Date::from_julian_day(2_451_545), Ok(date!(2000 - 01 - 01))); + /// assert_eq!(Date::from_julian_day(2_458_485), Ok(date!(2019 - 01 - 01))); + /// assert_eq!(Date::from_julian_day(2_458_849), Ok(date!(2019 - 12 - 31))); + /// ``` + #[doc(alias = "from_julian_date")] + pub const fn from_julian_day(julian_day: i32) -> Result<Self, error::ComponentRange> { + ensure_value_in_range!( + julian_day in Self::MIN.to_julian_day() => Self::MAX.to_julian_day() + ); + Ok(Self::from_julian_day_unchecked(julian_day)) + } + + /// Create a `Date` from the Julian day. + /// + /// This does not check the validity of the provided Julian day, and as such may result in an + /// internally invalid value. + #[doc(alias = "from_julian_date_unchecked")] + pub(crate) const fn from_julian_day_unchecked(julian_day: i32) -> Self { + debug_assert!(julian_day >= Self::MIN.to_julian_day()); + debug_assert!(julian_day <= Self::MAX.to_julian_day()); + + // To avoid a potential overflow, the value may need to be widened for some arithmetic. + + let z = julian_day - 1_721_119; + let (mut year, mut ordinal) = if julian_day < -19_752_948 || julian_day > 23_195_514 { + let g = 100 * z as i64 - 25; + let a = (g / 3_652_425) as i32; + let b = a - a / 4; + let year = div_floor!(100 * b as i64 + g, 36525) as i32; + let ordinal = (b + z - div_floor!(36525 * year as i64, 100) as i32) as _; + (year, ordinal) + } else { + let g = 100 * z - 25; + let a = g / 3_652_425; + let b = a - a / 4; + let year = div_floor!(100 * b + g, 36525); + let ordinal = (b + z - div_floor!(36525 * year, 100)) as _; + (year, ordinal) + }; + + if is_leap_year(year) { + ordinal += 60; + cascade!(ordinal in 1..367 => year); + } else { + ordinal += 59; + cascade!(ordinal in 1..366 => year); + } + + Self::__from_ordinal_date_unchecked(year, ordinal) + } + // endregion constructors + + // region: getters + /// Get the year of the date. + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).year(), 2019); + /// assert_eq!(date!(2019 - 12 - 31).year(), 2019); + /// assert_eq!(date!(2020 - 01 - 01).year(), 2020); + /// ``` + pub const fn year(self) -> i32 { + self.value >> 9 + } + + /// Get the month. + /// + /// ```rust + /// # use time::Month; + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).month(), Month::January); + /// assert_eq!(date!(2019 - 12 - 31).month(), Month::December); + /// ``` + pub const fn month(self) -> Month { + self.month_day().0 + } + + /// Get the day of the month. + /// + /// The returned value will always be in the range `1..=31`. + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).day(), 1); + /// assert_eq!(date!(2019 - 12 - 31).day(), 31); + /// ``` + pub const fn day(self) -> u8 { + self.month_day().1 + } + + /// Get the month and day. This is more efficient than fetching the components individually. + // For whatever reason, rustc has difficulty optimizing this function. It's significantly faster + // to write the statements out by hand. + pub(crate) const fn month_day(self) -> (Month, u8) { + /// The number of days up to and including the given month. Common years + /// are first, followed by leap years. + const CUMULATIVE_DAYS_IN_MONTH_COMMON_LEAP: [[u16; 11]; 2] = [ + [31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334], + [31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335], + ]; + + let days = CUMULATIVE_DAYS_IN_MONTH_COMMON_LEAP[is_leap_year(self.year()) as usize]; + let ordinal = self.ordinal(); + + if ordinal > days[10] { + (Month::December, (ordinal - days[10]) as _) + } else if ordinal > days[9] { + (Month::November, (ordinal - days[9]) as _) + } else if ordinal > days[8] { + (Month::October, (ordinal - days[8]) as _) + } else if ordinal > days[7] { + (Month::September, (ordinal - days[7]) as _) + } else if ordinal > days[6] { + (Month::August, (ordinal - days[6]) as _) + } else if ordinal > days[5] { + (Month::July, (ordinal - days[5]) as _) + } else if ordinal > days[4] { + (Month::June, (ordinal - days[4]) as _) + } else if ordinal > days[3] { + (Month::May, (ordinal - days[3]) as _) + } else if ordinal > days[2] { + (Month::April, (ordinal - days[2]) as _) + } else if ordinal > days[1] { + (Month::March, (ordinal - days[1]) as _) + } else if ordinal > days[0] { + (Month::February, (ordinal - days[0]) as _) + } else { + (Month::January, ordinal as _) + } + } + + /// Get the day of the year. + /// + /// The returned value will always be in the range `1..=366` (`1..=365` for common years). + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).ordinal(), 1); + /// assert_eq!(date!(2019 - 12 - 31).ordinal(), 365); + /// ``` + pub const fn ordinal(self) -> u16 { + (self.value & 0x1FF) as _ + } + + /// Get the ISO 8601 year and week number. + pub(crate) const fn iso_year_week(self) -> (i32, u8) { + let (year, ordinal) = self.to_ordinal_date(); + + match ((ordinal + 10 - self.weekday().number_from_monday() as u16) / 7) as _ { + 0 => (year - 1, weeks_in_year(year - 1)), + 53 if weeks_in_year(year) == 52 => (year + 1, 1), + week => (year, week), + } + } + + /// Get the ISO week number. + /// + /// The returned value will always be in the range `1..=53`. + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).iso_week(), 1); + /// assert_eq!(date!(2019 - 10 - 04).iso_week(), 40); + /// assert_eq!(date!(2020 - 01 - 01).iso_week(), 1); + /// assert_eq!(date!(2020 - 12 - 31).iso_week(), 53); + /// assert_eq!(date!(2021 - 01 - 01).iso_week(), 53); + /// ``` + pub const fn iso_week(self) -> u8 { + self.iso_year_week().1 + } + + /// Get the week number where week 1 begins on the first Sunday. + /// + /// The returned value will always be in the range `0..=53`. + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).sunday_based_week(), 0); + /// assert_eq!(date!(2020 - 01 - 01).sunday_based_week(), 0); + /// assert_eq!(date!(2020 - 12 - 31).sunday_based_week(), 52); + /// assert_eq!(date!(2021 - 01 - 01).sunday_based_week(), 0); + /// ``` + pub const fn sunday_based_week(self) -> u8 { + ((self.ordinal() as i16 - self.weekday().number_days_from_sunday() as i16 + 6) / 7) as _ + } + + /// Get the week number where week 1 begins on the first Monday. + /// + /// The returned value will always be in the range `0..=53`. + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).monday_based_week(), 0); + /// assert_eq!(date!(2020 - 01 - 01).monday_based_week(), 0); + /// assert_eq!(date!(2020 - 12 - 31).monday_based_week(), 52); + /// assert_eq!(date!(2021 - 01 - 01).monday_based_week(), 0); + /// ``` + pub const fn monday_based_week(self) -> u8 { + ((self.ordinal() as i16 - self.weekday().number_days_from_monday() as i16 + 6) / 7) as _ + } + + /// Get the year, month, and day. + /// + /// ```rust + /// # use time::Month; + /// # use time_macros::date; + /// assert_eq!( + /// date!(2019 - 01 - 01).to_calendar_date(), + /// (2019, Month::January, 1) + /// ); + /// ``` + pub const fn to_calendar_date(self) -> (i32, Month, u8) { + let (month, day) = self.month_day(); + (self.year(), month, day) + } + + /// Get the year and ordinal day number. + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).to_ordinal_date(), (2019, 1)); + /// ``` + pub const fn to_ordinal_date(self) -> (i32, u16) { + (self.year(), self.ordinal()) + } + + /// Get the ISO 8601 year, week number, and weekday. + /// + /// ```rust + /// # use time::Weekday::*; + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).to_iso_week_date(), (2019, 1, Tuesday)); + /// assert_eq!(date!(2019 - 10 - 04).to_iso_week_date(), (2019, 40, Friday)); + /// assert_eq!( + /// date!(2020 - 01 - 01).to_iso_week_date(), + /// (2020, 1, Wednesday) + /// ); + /// assert_eq!( + /// date!(2020 - 12 - 31).to_iso_week_date(), + /// (2020, 53, Thursday) + /// ); + /// assert_eq!(date!(2021 - 01 - 01).to_iso_week_date(), (2020, 53, Friday)); + /// ``` + pub const fn to_iso_week_date(self) -> (i32, u8, Weekday) { + let (year, ordinal) = self.to_ordinal_date(); + let weekday = self.weekday(); + + match ((ordinal + 10 - self.weekday().number_from_monday() as u16) / 7) as _ { + 0 => (year - 1, weeks_in_year(year - 1), weekday), + 53 if weeks_in_year(year) == 52 => (year + 1, 1, weekday), + week => (year, week, weekday), + } + } + + /// Get the weekday. + /// + /// ```rust + /// # use time::Weekday::*; + /// # use time_macros::date; + /// assert_eq!(date!(2019 - 01 - 01).weekday(), Tuesday); + /// assert_eq!(date!(2019 - 02 - 01).weekday(), Friday); + /// assert_eq!(date!(2019 - 03 - 01).weekday(), Friday); + /// assert_eq!(date!(2019 - 04 - 01).weekday(), Monday); + /// assert_eq!(date!(2019 - 05 - 01).weekday(), Wednesday); + /// assert_eq!(date!(2019 - 06 - 01).weekday(), Saturday); + /// assert_eq!(date!(2019 - 07 - 01).weekday(), Monday); + /// assert_eq!(date!(2019 - 08 - 01).weekday(), Thursday); + /// assert_eq!(date!(2019 - 09 - 01).weekday(), Sunday); + /// assert_eq!(date!(2019 - 10 - 01).weekday(), Tuesday); + /// assert_eq!(date!(2019 - 11 - 01).weekday(), Friday); + /// assert_eq!(date!(2019 - 12 - 01).weekday(), Sunday); + /// ``` + pub const fn weekday(self) -> Weekday { + match self.to_julian_day() % 7 { + -6 | 1 => Weekday::Tuesday, + -5 | 2 => Weekday::Wednesday, + -4 | 3 => Weekday::Thursday, + -3 | 4 => Weekday::Friday, + -2 | 5 => Weekday::Saturday, + -1 | 6 => Weekday::Sunday, + val => { + debug_assert!(val == 0); + Weekday::Monday + } + } + } + + /// Get the next calendar date. + /// + /// ```rust + /// # use time::Date; + /// # use time_macros::date; + /// assert_eq!( + /// date!(2019 - 01 - 01).next_day(), + /// Some(date!(2019 - 01 - 02)) + /// ); + /// assert_eq!( + /// date!(2019 - 01 - 31).next_day(), + /// Some(date!(2019 - 02 - 01)) + /// ); + /// assert_eq!( + /// date!(2019 - 12 - 31).next_day(), + /// Some(date!(2020 - 01 - 01)) + /// ); + /// assert_eq!(Date::MAX.next_day(), None); + /// ``` + pub const fn next_day(self) -> Option<Self> { + if self.ordinal() == 366 || (self.ordinal() == 365 && !is_leap_year(self.year())) { + if self.value == Self::MAX.value { + None + } else { + Some(Self::__from_ordinal_date_unchecked(self.year() + 1, 1)) + } + } else { + Some(Self { + value: self.value + 1, + }) + } + } + + /// Get the previous calendar date. + /// + /// ```rust + /// # use time::Date; + /// # use time_macros::date; + /// assert_eq!( + /// date!(2019 - 01 - 02).previous_day(), + /// Some(date!(2019 - 01 - 01)) + /// ); + /// assert_eq!( + /// date!(2019 - 02 - 01).previous_day(), + /// Some(date!(2019 - 01 - 31)) + /// ); + /// assert_eq!( + /// date!(2020 - 01 - 01).previous_day(), + /// Some(date!(2019 - 12 - 31)) + /// ); + /// assert_eq!(Date::MIN.previous_day(), None); + /// ``` + pub const fn previous_day(self) -> Option<Self> { + if self.ordinal() != 1 { + Some(Self { + value: self.value - 1, + }) + } else if self.value == Self::MIN.value { + None + } else { + Some(Self::__from_ordinal_date_unchecked( + self.year() - 1, + days_in_year(self.year() - 1), + )) + } + } + + /// Get the Julian day for the date. + /// + /// The algorithm to perform this conversion is derived from one provided by Peter Baum; it is + /// freely available [here](https://www.researchgate.net/publication/316558298_Date_Algorithms). + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!(date!(-4713 - 11 - 24).to_julian_day(), 0); + /// assert_eq!(date!(2000 - 01 - 01).to_julian_day(), 2_451_545); + /// assert_eq!(date!(2019 - 01 - 01).to_julian_day(), 2_458_485); + /// assert_eq!(date!(2019 - 12 - 31).to_julian_day(), 2_458_849); + /// ``` + pub const fn to_julian_day(self) -> i32 { + let year = self.year() - 1; + let ordinal = self.ordinal() as i32; + + ordinal + 365 * year + div_floor!(year, 4) - div_floor!(year, 100) + + div_floor!(year, 400) + + 1_721_425 + } + // endregion getters + + // region: checked arithmetic + /// Computes `self + duration`, returning `None` if an overflow occurred. + /// + /// ```rust + /// # use time::{Date, ext::NumericalDuration}; + /// # use time_macros::date; + /// assert_eq!(Date::MAX.checked_add(1.days()), None); + /// assert_eq!(Date::MIN.checked_add((-2).days()), None); + /// assert_eq!( + /// date!(2020 - 12 - 31).checked_add(2.days()), + /// Some(date!(2021 - 01 - 02)) + /// ); + /// ``` + /// + /// # Note + /// + /// This function only takes whole days into account. + /// + /// ```rust + /// # use time::{Date, ext::NumericalDuration}; + /// # use time_macros::date; + /// assert_eq!(Date::MAX.checked_add(23.hours()), Some(Date::MAX)); + /// assert_eq!(Date::MIN.checked_add((-23).hours()), Some(Date::MIN)); + /// assert_eq!( + /// date!(2020 - 12 - 31).checked_add(23.hours()), + /// Some(date!(2020 - 12 - 31)) + /// ); + /// assert_eq!( + /// date!(2020 - 12 - 31).checked_add(47.hours()), + /// Some(date!(2021 - 01 - 01)) + /// ); + /// ``` + pub const fn checked_add(self, duration: Duration) -> Option<Self> { + let whole_days = duration.whole_days(); + if whole_days < i32::MIN as i64 || whole_days > i32::MAX as i64 { + return None; + } + + let julian_day = const_try_opt!(self.to_julian_day().checked_add(whole_days as _)); + if let Ok(date) = Self::from_julian_day(julian_day) { + Some(date) + } else { + None + } + } + + /// Computes `self - duration`, returning `None` if an overflow occurred. + /// + /// ``` + /// # use time::{Date, ext::NumericalDuration}; + /// # use time_macros::date; + /// assert_eq!(Date::MAX.checked_sub((-2).days()), None); + /// assert_eq!(Date::MIN.checked_sub(1.days()), None); + /// assert_eq!( + /// date!(2020 - 12 - 31).checked_sub(2.days()), + /// Some(date!(2020 - 12 - 29)) + /// ); + /// ``` + /// + /// # Note + /// + /// This function only takes whole days into account. + /// + /// ``` + /// # use time::{Date, ext::NumericalDuration}; + /// # use time_macros::date; + /// assert_eq!(Date::MAX.checked_sub((-23).hours()), Some(Date::MAX)); + /// assert_eq!(Date::MIN.checked_sub(23.hours()), Some(Date::MIN)); + /// assert_eq!( + /// date!(2020 - 12 - 31).checked_sub(23.hours()), + /// Some(date!(2020 - 12 - 31)) + /// ); + /// assert_eq!( + /// date!(2020 - 12 - 31).checked_sub(47.hours()), + /// Some(date!(2020 - 12 - 30)) + /// ); + /// ``` + pub const fn checked_sub(self, duration: Duration) -> Option<Self> { + let whole_days = duration.whole_days(); + if whole_days < i32::MIN as i64 || whole_days > i32::MAX as i64 { + return None; + } + + let julian_day = const_try_opt!(self.to_julian_day().checked_sub(whole_days as _)); + if let Ok(date) = Self::from_julian_day(julian_day) { + Some(date) + } else { + None + } + } + // endregion: checked arithmetic + + // region: saturating arithmetic + /// Computes `self + duration`, saturating value on overflow. + /// + /// ```rust + /// # use time::{Date, ext::NumericalDuration}; + /// # use time_macros::date; + /// assert_eq!(Date::MAX.saturating_add(1.days()), Date::MAX); + /// assert_eq!(Date::MIN.saturating_add((-2).days()), Date::MIN); + /// assert_eq!( + /// date!(2020 - 12 - 31).saturating_add(2.days()), + /// date!(2021 - 01 - 02) + /// ); + /// ``` + /// + /// # Note + /// + /// This function only takes whole days into account. + /// + /// ```rust + /// # use time::ext::NumericalDuration; + /// # use time_macros::date; + /// assert_eq!( + /// date!(2020 - 12 - 31).saturating_add(23.hours()), + /// date!(2020 - 12 - 31) + /// ); + /// assert_eq!( + /// date!(2020 - 12 - 31).saturating_add(47.hours()), + /// date!(2021 - 01 - 01) + /// ); + /// ``` + pub const fn saturating_add(self, duration: Duration) -> Self { + if let Some(datetime) = self.checked_add(duration) { + datetime + } else if duration.is_negative() { + Self::MIN + } else { + debug_assert!(duration.is_positive()); + Self::MAX + } + } + + /// Computes `self - duration`, saturating value on overflow. + /// + /// ``` + /// # use time::{Date, ext::NumericalDuration}; + /// # use time_macros::date; + /// assert_eq!(Date::MAX.saturating_sub((-2).days()), Date::MAX); + /// assert_eq!(Date::MIN.saturating_sub(1.days()), Date::MIN); + /// assert_eq!( + /// date!(2020 - 12 - 31).saturating_sub(2.days()), + /// date!(2020 - 12 - 29) + /// ); + /// ``` + /// + /// # Note + /// + /// This function only takes whole days into account. + /// + /// ``` + /// # use time::ext::NumericalDuration; + /// # use time_macros::date; + /// assert_eq!( + /// date!(2020 - 12 - 31).saturating_sub(23.hours()), + /// date!(2020 - 12 - 31) + /// ); + /// assert_eq!( + /// date!(2020 - 12 - 31).saturating_sub(47.hours()), + /// date!(2020 - 12 - 30) + /// ); + /// ``` + pub const fn saturating_sub(self, duration: Duration) -> Self { + if let Some(datetime) = self.checked_sub(duration) { + datetime + } else if duration.is_negative() { + Self::MAX + } else { + debug_assert!(duration.is_positive()); + Self::MIN + } + } + // region: saturating arithmetic + + // region: replacement + /// Replace the year. The month and day will be unchanged. + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!( + /// date!(2022 - 02 - 18).replace_year(2019), + /// Ok(date!(2019 - 02 - 18)) + /// ); + /// assert!(date!(2022 - 02 - 18).replace_year(-1_000_000_000).is_err()); // -1_000_000_000 isn't a valid year + /// assert!(date!(2022 - 02 - 18).replace_year(1_000_000_000).is_err()); // 1_000_000_000 isn't a valid year + /// ``` + #[must_use = "This method does not mutate the original `Date`."] + pub const fn replace_year(self, year: i32) -> Result<Self, error::ComponentRange> { + ensure_value_in_range!(year in MIN_YEAR => MAX_YEAR); + + let ordinal = self.ordinal(); + + // Dates in January and February are unaffected by leap years. + if ordinal <= 59 { + return Ok(Self::__from_ordinal_date_unchecked(year, ordinal)); + } + + match (is_leap_year(self.year()), is_leap_year(year)) { + (false, false) | (true, true) => Ok(Self::__from_ordinal_date_unchecked(year, ordinal)), + // February 29 does not exist in common years. + (true, false) if ordinal == 60 => Err(error::ComponentRange { + name: "day", + value: 29, + minimum: 1, + maximum: 28, + conditional_range: true, + }), + // We're going from a common year to a leap year. Shift dates in March and later by + // one day. + (false, true) => Ok(Self::__from_ordinal_date_unchecked(year, ordinal + 1)), + // We're going from a leap year to a common year. Shift dates in January and + // February by one day. + (true, false) => Ok(Self::__from_ordinal_date_unchecked(year, ordinal - 1)), + } + } + + /// Replace the month of the year. + /// + /// ```rust + /// # use time_macros::date; + /// # use time::Month; + /// assert_eq!( + /// date!(2022 - 02 - 18).replace_month(Month::January), + /// Ok(date!(2022 - 01 - 18)) + /// ); + /// assert!( + /// date!(2022 - 01 - 30) + /// .replace_month(Month::February) + /// .is_err() + /// ); // 30 isn't a valid day in February + /// ``` + #[must_use = "This method does not mutate the original `Date`."] + pub const fn replace_month(self, month: Month) -> Result<Self, error::ComponentRange> { + let (year, _, day) = self.to_calendar_date(); + Self::from_calendar_date(year, month, day) + } + + /// Replace the day of the month. + /// + /// ```rust + /// # use time_macros::date; + /// assert_eq!( + /// date!(2022 - 02 - 18).replace_day(1), + /// Ok(date!(2022 - 02 - 01)) + /// ); + /// assert!(date!(2022 - 02 - 18).replace_day(0).is_err()); // 0 isn't a valid day + /// assert!(date!(2022 - 02 - 18).replace_day(30).is_err()); // 30 isn't a valid day in February + /// ``` + #[must_use = "This method does not mutate the original `Date`."] + pub const fn replace_day(self, day: u8) -> Result<Self, error::ComponentRange> { + // Days 1-28 are present in every month, so we can skip checking. + if day == 0 || day >= 29 { + ensure_value_in_range!( + day conditionally in 1 => days_in_year_month(self.year(), self.month()) + ); + } + + Ok(Self::__from_ordinal_date_unchecked( + self.year(), + (self.ordinal() as i16 - self.day() as i16 + day as i16) as _, + )) + } + // endregion replacement +} + +// region: attach time +/// Methods to add a [`Time`] component, resulting in a [`PrimitiveDateTime`]. +impl Date { + /// Create a [`PrimitiveDateTime`] using the existing date. The [`Time`] component will be set + /// to midnight. + /// + /// ```rust + /// # use time_macros::{date, datetime}; + /// assert_eq!(date!(1970-01-01).midnight(), datetime!(1970-01-01 0:00)); + /// ``` + pub const fn midnight(self) -> PrimitiveDateTime { + PrimitiveDateTime::new(self, Time::MIDNIGHT) + } + + /// Create a [`PrimitiveDateTime`] using the existing date and the provided [`Time`]. + /// + /// ```rust + /// # use time_macros::{date, datetime, time}; + /// assert_eq!( + /// date!(1970-01-01).with_time(time!(0:00)), + /// datetime!(1970-01-01 0:00), + /// ); + /// ``` + pub const fn with_time(self, time: Time) -> PrimitiveDateTime { + PrimitiveDateTime::new(self, time) + } + + /// Attempt to create a [`PrimitiveDateTime`] using the existing date and the provided time. + /// + /// ```rust + /// # use time_macros::date; + /// assert!(date!(1970 - 01 - 01).with_hms(0, 0, 0).is_ok()); + /// assert!(date!(1970 - 01 - 01).with_hms(24, 0, 0).is_err()); + /// ``` + pub const fn with_hms( + self, + hour: u8, + minute: u8, + second: u8, + ) -> Result<PrimitiveDateTime, error::ComponentRange> { + Ok(PrimitiveDateTime::new( + self, + const_try!(Time::from_hms(hour, minute, second)), + )) + } + + /// Attempt to create a [`PrimitiveDateTime`] using the existing date and the provided time. + /// + /// ```rust + /// # use time_macros::date; + /// assert!(date!(1970 - 01 - 01).with_hms_milli(0, 0, 0, 0).is_ok()); + /// assert!(date!(1970 - 01 - 01).with_hms_milli(24, 0, 0, 0).is_err()); + /// ``` + pub const fn with_hms_milli( + self, + hour: u8, + minute: u8, + second: u8, + millisecond: u16, + ) -> Result<PrimitiveDateTime, error::ComponentRange> { + Ok(PrimitiveDateTime::new( + self, + const_try!(Time::from_hms_milli(hour, minute, second, millisecond)), + )) + } + + /// Attempt to create a [`PrimitiveDateTime`] using the existing date and the provided time. + /// + /// ```rust + /// # use time_macros::date; + /// assert!(date!(1970 - 01 - 01).with_hms_micro(0, 0, 0, 0).is_ok()); + /// assert!(date!(1970 - 01 - 01).with_hms_micro(24, 0, 0, 0).is_err()); + /// ``` + pub const fn with_hms_micro( + self, + hour: u8, + minute: u8, + second: u8, + microsecond: u32, + ) -> Result<PrimitiveDateTime, error::ComponentRange> { + Ok(PrimitiveDateTime::new( + self, + const_try!(Time::from_hms_micro(hour, minute, second, microsecond)), + )) + } + + /// Attempt to create a [`PrimitiveDateTime`] using the existing date and the provided time. + /// + /// ```rust + /// # use time_macros::date; + /// assert!(date!(1970 - 01 - 01).with_hms_nano(0, 0, 0, 0).is_ok()); + /// assert!(date!(1970 - 01 - 01).with_hms_nano(24, 0, 0, 0).is_err()); + /// ``` + pub const fn with_hms_nano( + self, + hour: u8, + minute: u8, + second: u8, + nanosecond: u32, + ) -> Result<PrimitiveDateTime, error::ComponentRange> { + Ok(PrimitiveDateTime::new( + self, + const_try!(Time::from_hms_nano(hour, minute, second, nanosecond)), + )) + } +} +// endregion attach time + +// region: formatting & parsing +#[cfg(feature = "formatting")] +impl Date { + /// Format the `Date` using the provided [format description](crate::format_description). + pub fn format_into( + self, + output: &mut impl io::Write, + format: &(impl Formattable + ?Sized), + ) -> Result<usize, error::Format> { + format.format_into(output, Some(self), None, None) + } + + /// Format the `Date` using the provided [format description](crate::format_description). + /// + /// ```rust + /// # use time::{format_description}; + /// # use time_macros::date; + /// let format = format_description::parse("[year]-[month]-[day]")?; + /// assert_eq!(date!(2020 - 01 - 02).format(&format)?, "2020-01-02"); + /// # Ok::<_, time::Error>(()) + /// ``` + pub fn format(self, format: &(impl Formattable + ?Sized)) -> Result<String, error::Format> { + format.format(Some(self), None, None) + } +} + +#[cfg(feature = "parsing")] +impl Date { + /// Parse a `Date` from the input using the provided [format + /// description](crate::format_description). + /// + /// ```rust + /// # use time::Date; + /// # use time_macros::{date, format_description}; + /// let format = format_description!("[year]-[month]-[day]"); + /// assert_eq!(Date::parse("2020-01-02", &format)?, date!(2020 - 01 - 02)); + /// # Ok::<_, time::Error>(()) + /// ``` + pub fn parse( + input: &str, + description: &(impl Parsable + ?Sized), + ) -> Result<Self, error::Parse> { + description.parse_date(input.as_bytes()) + } +} + +impl fmt::Display for Date { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + if cfg!(feature = "large-dates") && self.year().abs() >= 10_000 { + write!( + f, + "{:+}-{:02}-{:02}", + self.year(), + self.month() as u8, + self.day() + ) + } else { + write!( + f, + "{:0width$}-{:02}-{:02}", + self.year(), + self.month() as u8, + self.day(), + width = 4 + (self.year() < 0) as usize + ) + } + } +} + +impl fmt::Debug for Date { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> { + fmt::Display::fmt(self, f) + } +} +// endregion formatting & parsing + +// region: trait impls +impl Add<Duration> for Date { + type Output = Self; + + fn add(self, duration: Duration) -> Self::Output { + self.checked_add(duration) + .expect("overflow adding duration to date") + } +} + +impl Add<StdDuration> for Date { + type Output = Self; + + fn add(self, duration: StdDuration) -> Self::Output { + Self::from_julian_day(self.to_julian_day() + (duration.as_secs() / 86_400) as i32) + .expect("overflow adding duration to date") + } +} + +impl_add_assign!(Date: Duration, StdDuration); + +impl Sub<Duration> for Date { + type Output = Self; + + fn sub(self, duration: Duration) -> Self::Output { + self.checked_sub(duration) + .expect("overflow subtracting duration from date") + } +} + +impl Sub<StdDuration> for Date { + type Output = Self; + + fn sub(self, duration: StdDuration) -> Self::Output { + Self::from_julian_day(self.to_julian_day() - (duration.as_secs() / 86_400) as i32) + .expect("overflow subtracting duration from date") + } +} + +impl_sub_assign!(Date: Duration, StdDuration); + +impl Sub for Date { + type Output = Duration; + + fn sub(self, other: Self) -> Self::Output { + Duration::days((self.to_julian_day() - other.to_julian_day()) as _) + } +} +// endregion trait impls |