| use crate::{IsoWeek, Weekday}; |
| |
| /// The common set of methods for date component. |
| pub trait Datelike: Sized { |
| /// Returns the year number in the [calendar date](./naive/struct.NaiveDate.html#calendar-date). |
| fn year(&self) -> i32; |
| |
| /// Returns the absolute year number starting from 1 with a boolean flag, |
| /// which is false when the year predates the epoch (BCE/BC) and true otherwise (CE/AD). |
| #[inline] |
| fn year_ce(&self) -> (bool, u32) { |
| let year = self.year(); |
| if year < 1 { |
| (false, (1 - year) as u32) |
| } else { |
| (true, year as u32) |
| } |
| } |
| |
| /// Returns the month number starting from 1. |
| /// |
| /// The return value ranges from 1 to 12. |
| fn month(&self) -> u32; |
| |
| /// Returns the month number starting from 0. |
| /// |
| /// The return value ranges from 0 to 11. |
| fn month0(&self) -> u32; |
| |
| /// Returns the day of month starting from 1. |
| /// |
| /// The return value ranges from 1 to 31. (The last day of month differs by months.) |
| fn day(&self) -> u32; |
| |
| /// Returns the day of month starting from 0. |
| /// |
| /// The return value ranges from 0 to 30. (The last day of month differs by months.) |
| fn day0(&self) -> u32; |
| |
| /// Returns the day of year starting from 1. |
| /// |
| /// The return value ranges from 1 to 366. (The last day of year differs by years.) |
| fn ordinal(&self) -> u32; |
| |
| /// Returns the day of year starting from 0. |
| /// |
| /// The return value ranges from 0 to 365. (The last day of year differs by years.) |
| fn ordinal0(&self) -> u32; |
| |
| /// Returns the day of week. |
| fn weekday(&self) -> Weekday; |
| |
| /// Returns the ISO week. |
| fn iso_week(&self) -> IsoWeek; |
| |
| /// Makes a new value with the year number changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_year(&self, year: i32) -> Option<Self>; |
| |
| /// Makes a new value with the month number (starting from 1) changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_month(&self, month: u32) -> Option<Self>; |
| |
| /// Makes a new value with the month number (starting from 0) changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_month0(&self, month0: u32) -> Option<Self>; |
| |
| /// Makes a new value with the day of month (starting from 1) changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_day(&self, day: u32) -> Option<Self>; |
| |
| /// Makes a new value with the day of month (starting from 0) changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_day0(&self, day0: u32) -> Option<Self>; |
| |
| /// Makes a new value with the day of year (starting from 1) changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_ordinal(&self, ordinal: u32) -> Option<Self>; |
| |
| /// Makes a new value with the day of year (starting from 0) changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_ordinal0(&self, ordinal0: u32) -> Option<Self>; |
| |
| /// Counts the days in the proleptic Gregorian calendar, with January 1, Year 1 (CE) as day 1. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// use chrono::{NaiveDate, Datelike}; |
| /// |
| /// assert_eq!(NaiveDate::from_ymd_opt(1970, 1, 1).unwrap().num_days_from_ce(), 719_163); |
| /// assert_eq!(NaiveDate::from_ymd_opt(2, 1, 1).unwrap().num_days_from_ce(), 366); |
| /// assert_eq!(NaiveDate::from_ymd_opt(1, 1, 1).unwrap().num_days_from_ce(), 1); |
| /// assert_eq!(NaiveDate::from_ymd_opt(0, 1, 1).unwrap().num_days_from_ce(), -365); |
| /// ``` |
| fn num_days_from_ce(&self) -> i32 { |
| // See test_num_days_from_ce_against_alternative_impl below for a more straightforward |
| // implementation. |
| |
| // we know this wouldn't overflow since year is limited to 1/2^13 of i32's full range. |
| let mut year = self.year() - 1; |
| let mut ndays = 0; |
| if year < 0 { |
| let excess = 1 + (-year) / 400; |
| year += excess * 400; |
| ndays -= excess * 146_097; |
| } |
| let div_100 = year / 100; |
| ndays += ((year * 1461) >> 2) - div_100 + (div_100 >> 2); |
| ndays + self.ordinal() as i32 |
| } |
| } |
| |
| /// The common set of methods for time component. |
| pub trait Timelike: Sized { |
| /// Returns the hour number from 0 to 23. |
| fn hour(&self) -> u32; |
| |
| /// Returns the hour number from 1 to 12 with a boolean flag, |
| /// which is false for AM and true for PM. |
| #[inline] |
| fn hour12(&self) -> (bool, u32) { |
| let hour = self.hour(); |
| let mut hour12 = hour % 12; |
| if hour12 == 0 { |
| hour12 = 12; |
| } |
| (hour >= 12, hour12) |
| } |
| |
| /// Returns the minute number from 0 to 59. |
| fn minute(&self) -> u32; |
| |
| /// Returns the second number from 0 to 59. |
| fn second(&self) -> u32; |
| |
| /// Returns the number of nanoseconds since the whole non-leap second. |
| /// The range from 1,000,000,000 to 1,999,999,999 represents |
| /// the [leap second](./naive/struct.NaiveTime.html#leap-second-handling). |
| fn nanosecond(&self) -> u32; |
| |
| /// Makes a new value with the hour number changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_hour(&self, hour: u32) -> Option<Self>; |
| |
| /// Makes a new value with the minute number changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| fn with_minute(&self, min: u32) -> Option<Self>; |
| |
| /// Makes a new value with the second number changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| /// As with the [`second`](#tymethod.second) method, |
| /// the input range is restricted to 0 through 59. |
| fn with_second(&self, sec: u32) -> Option<Self>; |
| |
| /// Makes a new value with nanoseconds since the whole non-leap second changed. |
| /// |
| /// Returns `None` when the resulting value would be invalid. |
| /// As with the [`nanosecond`](#tymethod.nanosecond) method, |
| /// the input range can exceed 1,000,000,000 for leap seconds. |
| fn with_nanosecond(&self, nano: u32) -> Option<Self>; |
| |
| /// Returns the number of non-leap seconds past the last midnight. |
| #[inline] |
| fn num_seconds_from_midnight(&self) -> u32 { |
| self.hour() * 3600 + self.minute() * 60 + self.second() |
| } |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use super::Datelike; |
| use crate::{Duration, NaiveDate}; |
| |
| /// Tests `Datelike::num_days_from_ce` against an alternative implementation. |
| /// |
| /// The alternative implementation is not as short as the current one but it is simpler to |
| /// understand, with less unexplained magic constants. |
| #[test] |
| fn test_num_days_from_ce_against_alternative_impl() { |
| /// Returns the number of multiples of `div` in the range `start..end`. |
| /// |
| /// If the range `start..end` is back-to-front, i.e. `start` is greater than `end`, the |
| /// behaviour is defined by the following equation: |
| /// `in_between(start, end, div) == - in_between(end, start, div)`. |
| /// |
| /// When `div` is 1, this is equivalent to `end - start`, i.e. the length of `start..end`. |
| /// |
| /// # Panics |
| /// |
| /// Panics if `div` is not positive. |
| fn in_between(start: i32, end: i32, div: i32) -> i32 { |
| assert!(div > 0, "in_between: nonpositive div = {}", div); |
| let start = (start.div_euclid(div), start.rem_euclid(div)); |
| let end = (end.div_euclid(div), end.rem_euclid(div)); |
| // The lowest multiple of `div` greater than or equal to `start`, divided. |
| let start = start.0 + (start.1 != 0) as i32; |
| // The lowest multiple of `div` greater than or equal to `end`, divided. |
| let end = end.0 + (end.1 != 0) as i32; |
| end - start |
| } |
| |
| /// Alternative implementation to `Datelike::num_days_from_ce` |
| fn num_days_from_ce<Date: Datelike>(date: &Date) -> i32 { |
| let year = date.year(); |
| let diff = move |div| in_between(1, year, div); |
| // 365 days a year, one more in leap years. In the gregorian calendar, leap years are all |
| // the multiples of 4 except multiples of 100 but including multiples of 400. |
| date.ordinal() as i32 + 365 * diff(1) + diff(4) - diff(100) + diff(400) |
| } |
| |
| use num_iter::range_inclusive; |
| |
| for year in range_inclusive(NaiveDate::MIN.year(), NaiveDate::MAX.year()) { |
| let jan1_year = NaiveDate::from_ymd_opt(year, 1, 1).unwrap(); |
| assert_eq!( |
| jan1_year.num_days_from_ce(), |
| num_days_from_ce(&jan1_year), |
| "on {:?}", |
| jan1_year |
| ); |
| let mid_year = jan1_year + Duration::days(133); |
| assert_eq!( |
| mid_year.num_days_from_ce(), |
| num_days_from_ce(&mid_year), |
| "on {:?}", |
| mid_year |
| ); |
| } |
| } |
| } |