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Diffstat (limited to 'src/offset/mod.rs')
| -rw-r--r-- | src/offset/mod.rs | 531 |
1 files changed, 531 insertions, 0 deletions
diff --git a/src/offset/mod.rs b/src/offset/mod.rs new file mode 100644 index 0000000..0da6bfb --- /dev/null +++ b/src/offset/mod.rs @@ -0,0 +1,531 @@ +// This is a part of Chrono. +// See README.md and LICENSE.txt for details. + +//! The time zone, which calculates offsets from the local time to UTC. +//! +//! There are four operations provided by the `TimeZone` trait: +//! +//! 1. Converting the local `NaiveDateTime` to `DateTime<Tz>` +//! 2. Converting the UTC `NaiveDateTime` to `DateTime<Tz>` +//! 3. Converting `DateTime<Tz>` to the local `NaiveDateTime` +//! 4. Constructing `DateTime<Tz>` objects from various offsets +//! +//! 1 is used for constructors. 2 is used for the `with_timezone` method of date and time types. +//! 3 is used for other methods, e.g. `year()` or `format()`, and provided by an associated type +//! which implements `Offset` (which then passed to `TimeZone` for actual implementations). +//! Technically speaking `TimeZone` has a total knowledge about given timescale, +//! but `Offset` is used as a cache to avoid the repeated conversion +//! and provides implementations for 1 and 3. +//! An `TimeZone` instance can be reconstructed from the corresponding `Offset` instance. + +use core::fmt; + +use format::{parse, ParseResult, Parsed, StrftimeItems}; +use naive::{NaiveDate, NaiveDateTime, NaiveTime}; +use Weekday; +use {Date, DateTime}; + +/// The conversion result from the local time to the timezone-aware datetime types. +#[derive(Clone, PartialEq, Debug, Copy, Eq, Hash)] +pub enum LocalResult<T> { + /// Given local time representation is invalid. + /// This can occur when, for example, the positive timezone transition. + None, + /// Given local time representation has a single unique result. + Single(T), + /// Given local time representation has multiple results and thus ambiguous. + /// This can occur when, for example, the negative timezone transition. + Ambiguous(T /*min*/, T /*max*/), +} + +impl<T> LocalResult<T> { + /// Returns `Some` only when the conversion result is unique, or `None` otherwise. + pub fn single(self) -> Option<T> { + match self { + LocalResult::Single(t) => Some(t), + _ => None, + } + } + + /// Returns `Some` for the earliest possible conversion result, or `None` if none. + pub fn earliest(self) -> Option<T> { + match self { + LocalResult::Single(t) | LocalResult::Ambiguous(t, _) => Some(t), + _ => None, + } + } + + /// Returns `Some` for the latest possible conversion result, or `None` if none. + pub fn latest(self) -> Option<T> { + match self { + LocalResult::Single(t) | LocalResult::Ambiguous(_, t) => Some(t), + _ => None, + } + } + + /// Maps a `LocalResult<T>` into `LocalResult<U>` with given function. + pub fn map<U, F: FnMut(T) -> U>(self, mut f: F) -> LocalResult<U> { + match self { + LocalResult::None => LocalResult::None, + LocalResult::Single(v) => LocalResult::Single(f(v)), + LocalResult::Ambiguous(min, max) => LocalResult::Ambiguous(f(min), f(max)), + } + } +} + +impl<Tz: TimeZone> LocalResult<Date<Tz>> { + /// Makes a new `DateTime` from the current date and given `NaiveTime`. + /// The offset in the current date is preserved. + /// + /// Propagates any error. Ambiguous result would be discarded. + #[inline] + pub fn and_time(self, time: NaiveTime) -> LocalResult<DateTime<Tz>> { + match self { + LocalResult::Single(d) => { + d.and_time(time).map_or(LocalResult::None, LocalResult::Single) + } + _ => LocalResult::None, + } + } + + /// Makes a new `DateTime` from the current date, hour, minute and second. + /// The offset in the current date is preserved. + /// + /// Propagates any error. Ambiguous result would be discarded. + #[inline] + pub fn and_hms_opt(self, hour: u32, min: u32, sec: u32) -> LocalResult<DateTime<Tz>> { + match self { + LocalResult::Single(d) => { + d.and_hms_opt(hour, min, sec).map_or(LocalResult::None, LocalResult::Single) + } + _ => LocalResult::None, + } + } + + /// Makes a new `DateTime` from the current date, hour, minute, second and millisecond. + /// The millisecond part can exceed 1,000 in order to represent the leap second. + /// The offset in the current date is preserved. + /// + /// Propagates any error. Ambiguous result would be discarded. + #[inline] + pub fn and_hms_milli_opt( + self, + hour: u32, + min: u32, + sec: u32, + milli: u32, + ) -> LocalResult<DateTime<Tz>> { + match self { + LocalResult::Single(d) => d + .and_hms_milli_opt(hour, min, sec, milli) + .map_or(LocalResult::None, LocalResult::Single), + _ => LocalResult::None, + } + } + + /// Makes a new `DateTime` from the current date, hour, minute, second and microsecond. + /// The microsecond part can exceed 1,000,000 in order to represent the leap second. + /// The offset in the current date is preserved. + /// + /// Propagates any error. Ambiguous result would be discarded. + #[inline] + pub fn and_hms_micro_opt( + self, + hour: u32, + min: u32, + sec: u32, + micro: u32, + ) -> LocalResult<DateTime<Tz>> { + match self { + LocalResult::Single(d) => d + .and_hms_micro_opt(hour, min, sec, micro) + .map_or(LocalResult::None, LocalResult::Single), + _ => LocalResult::None, + } + } + + /// Makes a new `DateTime` from the current date, hour, minute, second and nanosecond. + /// The nanosecond part can exceed 1,000,000,000 in order to represent the leap second. + /// The offset in the current date is preserved. + /// + /// Propagates any error. Ambiguous result would be discarded. + #[inline] + pub fn and_hms_nano_opt( + self, + hour: u32, + min: u32, + sec: u32, + nano: u32, + ) -> LocalResult<DateTime<Tz>> { + match self { + LocalResult::Single(d) => d + .and_hms_nano_opt(hour, min, sec, nano) + .map_or(LocalResult::None, LocalResult::Single), + _ => LocalResult::None, + } + } +} + +impl<T: fmt::Debug> LocalResult<T> { + /// Returns the single unique conversion result, or panics accordingly. + pub fn unwrap(self) -> T { + match self { + LocalResult::None => panic!("No such local time"), + LocalResult::Single(t) => t, + LocalResult::Ambiguous(t1, t2) => { + panic!("Ambiguous local time, ranging from {:?} to {:?}", t1, t2) + } + } + } +} + +/// The offset from the local time to UTC. +pub trait Offset: Sized + Clone + fmt::Debug { + /// Returns the fixed offset from UTC to the local time stored. + fn fix(&self) -> FixedOffset; +} + +/// The time zone. +/// +/// The methods here are the primarily constructors for [`Date`](../struct.Date.html) and +/// [`DateTime`](../struct.DateTime.html) types. +pub trait TimeZone: Sized + Clone { + /// An associated offset type. + /// This type is used to store the actual offset in date and time types. + /// The original `TimeZone` value can be recovered via `TimeZone::from_offset`. + type Offset: Offset; + + /// Makes a new `Date` from year, month, day and the current time zone. + /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE. + /// + /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24), + /// but it will propagate to the `DateTime` values constructed via this date. + /// + /// Panics on the out-of-range date, invalid month and/or day. + /// + /// # Example + /// + /// ~~~~ + /// use chrono::{Utc, TimeZone}; + /// + /// assert_eq!(Utc.ymd(2015, 5, 15).to_string(), "2015-05-15UTC"); + /// ~~~~ + fn ymd(&self, year: i32, month: u32, day: u32) -> Date<Self> { + self.ymd_opt(year, month, day).unwrap() + } + + /// Makes a new `Date` from year, month, day and the current time zone. + /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE. + /// + /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24), + /// but it will propagate to the `DateTime` values constructed via this date. + /// + /// Returns `None` on the out-of-range date, invalid month and/or day. + /// + /// # Example + /// + /// ~~~~ + /// use chrono::{Utc, LocalResult, TimeZone}; + /// + /// assert_eq!(Utc.ymd_opt(2015, 5, 15).unwrap().to_string(), "2015-05-15UTC"); + /// assert_eq!(Utc.ymd_opt(2000, 0, 0), LocalResult::None); + /// ~~~~ + fn ymd_opt(&self, year: i32, month: u32, day: u32) -> LocalResult<Date<Self>> { + match NaiveDate::from_ymd_opt(year, month, day) { + Some(d) => self.from_local_date(&d), + None => LocalResult::None, + } + } + + /// Makes a new `Date` from year, day of year (DOY or "ordinal") and the current time zone. + /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE. + /// + /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24), + /// but it will propagate to the `DateTime` values constructed via this date. + /// + /// Panics on the out-of-range date and/or invalid DOY. + /// + /// # Example + /// + /// ~~~~ + /// use chrono::{Utc, TimeZone}; + /// + /// assert_eq!(Utc.yo(2015, 135).to_string(), "2015-05-15UTC"); + /// ~~~~ + fn yo(&self, year: i32, ordinal: u32) -> Date<Self> { + self.yo_opt(year, ordinal).unwrap() + } + + /// Makes a new `Date` from year, day of year (DOY or "ordinal") and the current time zone. + /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE. + /// + /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24), + /// but it will propagate to the `DateTime` values constructed via this date. + /// + /// Returns `None` on the out-of-range date and/or invalid DOY. + fn yo_opt(&self, year: i32, ordinal: u32) -> LocalResult<Date<Self>> { + match NaiveDate::from_yo_opt(year, ordinal) { + Some(d) => self.from_local_date(&d), + None => LocalResult::None, + } + } + + /// Makes a new `Date` from ISO week date (year and week number), day of the week (DOW) and + /// the current time zone. + /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE. + /// The resulting `Date` may have a different year from the input year. + /// + /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24), + /// but it will propagate to the `DateTime` values constructed via this date. + /// + /// Panics on the out-of-range date and/or invalid week number. + /// + /// # Example + /// + /// ~~~~ + /// use chrono::{Utc, Weekday, TimeZone}; + /// + /// assert_eq!(Utc.isoywd(2015, 20, Weekday::Fri).to_string(), "2015-05-15UTC"); + /// ~~~~ + fn isoywd(&self, year: i32, week: u32, weekday: Weekday) -> Date<Self> { + self.isoywd_opt(year, week, weekday).unwrap() + } + + /// Makes a new `Date` from ISO week date (year and week number), day of the week (DOW) and + /// the current time zone. + /// This assumes the proleptic Gregorian calendar, with the year 0 being 1 BCE. + /// The resulting `Date` may have a different year from the input year. + /// + /// The time zone normally does not affect the date (unless it is between UTC-24 and UTC+24), + /// but it will propagate to the `DateTime` values constructed via this date. + /// + /// Returns `None` on the out-of-range date and/or invalid week number. + fn isoywd_opt(&self, year: i32, week: u32, weekday: Weekday) -> LocalResult<Date<Self>> { + match NaiveDate::from_isoywd_opt(year, week, weekday) { + Some(d) => self.from_local_date(&d), + None => LocalResult::None, + } + } + + /// Makes a new `DateTime` from the number of non-leap seconds + /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp") + /// and the number of nanoseconds since the last whole non-leap second. + /// + /// Panics on the out-of-range number of seconds and/or invalid nanosecond, + /// for a non-panicking version see [`timestamp_opt`](#method.timestamp_opt). + /// + /// # Example + /// + /// ~~~~ + /// use chrono::{Utc, TimeZone}; + /// + /// assert_eq!(Utc.timestamp(1431648000, 0).to_string(), "2015-05-15 00:00:00 UTC"); + /// ~~~~ + fn timestamp(&self, secs: i64, nsecs: u32) -> DateTime<Self> { + self.timestamp_opt(secs, nsecs).unwrap() + } + + /// Makes a new `DateTime` from the number of non-leap seconds + /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp") + /// and the number of nanoseconds since the last whole non-leap second. + /// + /// Returns `LocalResult::None` on out-of-range number of seconds and/or + /// invalid nanosecond, otherwise always returns `LocalResult::Single`. + fn timestamp_opt(&self, secs: i64, nsecs: u32) -> LocalResult<DateTime<Self>> { + match NaiveDateTime::from_timestamp_opt(secs, nsecs) { + Some(dt) => LocalResult::Single(self.from_utc_datetime(&dt)), + None => LocalResult::None, + } + } + + /// Makes a new `DateTime` from the number of non-leap milliseconds + /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp"). + /// + /// Panics on out-of-range number of milliseconds for a non-panicking + /// version see [`timestamp_millis_opt`](#method.timestamp_millis_opt). + /// + /// # Example + /// + /// ~~~~ + /// use chrono::{Utc, TimeZone}; + /// + /// assert_eq!(Utc.timestamp_millis(1431648000).timestamp(), 1431648); + /// ~~~~ + fn timestamp_millis(&self, millis: i64) -> DateTime<Self> { + self.timestamp_millis_opt(millis).unwrap() + } + + /// Makes a new `DateTime` from the number of non-leap milliseconds + /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp"). + /// + /// + /// Returns `LocalResult::None` on out-of-range number of milliseconds + /// and/or invalid nanosecond, otherwise always returns + /// `LocalResult::Single`. + /// + /// # Example + /// + /// ~~~~ + /// use chrono::{Utc, TimeZone, LocalResult}; + /// match Utc.timestamp_millis_opt(1431648000) { + /// LocalResult::Single(dt) => assert_eq!(dt.timestamp(), 1431648), + /// _ => panic!("Incorrect timestamp_millis"), + /// }; + /// ~~~~ + fn timestamp_millis_opt(&self, millis: i64) -> LocalResult<DateTime<Self>> { + let (mut secs, mut millis) = (millis / 1000, millis % 1000); + if millis < 0 { + secs -= 1; + millis += 1000; + } + self.timestamp_opt(secs, millis as u32 * 1_000_000) + } + + /// Makes a new `DateTime` from the number of non-leap nanoseconds + /// since January 1, 1970 0:00:00 UTC (aka "UNIX timestamp"). + /// + /// Unlike [`timestamp_millis`](#method.timestamp_millis), this never + /// panics. + /// + /// # Example + /// + /// ~~~~ + /// use chrono::{Utc, TimeZone}; + /// + /// assert_eq!(Utc.timestamp_nanos(1431648000000000).timestamp(), 1431648); + /// ~~~~ + fn timestamp_nanos(&self, nanos: i64) -> DateTime<Self> { + let (mut secs, mut nanos) = (nanos / 1_000_000_000, nanos % 1_000_000_000); + if nanos < 0 { + secs -= 1; + nanos += 1_000_000_000; + } + self.timestamp_opt(secs, nanos as u32).unwrap() + } + + /// Parses a string with the specified format string and + /// returns a `DateTime` with the current offset. + /// See the [`format::strftime` module](../format/strftime/index.html) + /// on the supported escape sequences. + /// + /// If the format does not include offsets, the current offset is assumed; + /// otherwise the input should have a matching UTC offset. + /// + /// See also `DateTime::parse_from_str` which gives a local `DateTime` + /// with parsed `FixedOffset`. + fn datetime_from_str(&self, s: &str, fmt: &str) -> ParseResult<DateTime<Self>> { + let mut parsed = Parsed::new(); + parse(&mut parsed, s, StrftimeItems::new(fmt))?; + parsed.to_datetime_with_timezone(self) + } + + /// Reconstructs the time zone from the offset. + fn from_offset(offset: &Self::Offset) -> Self; + + /// Creates the offset(s) for given local `NaiveDate` if possible. + fn offset_from_local_date(&self, local: &NaiveDate) -> LocalResult<Self::Offset>; + + /// Creates the offset(s) for given local `NaiveDateTime` if possible. + fn offset_from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<Self::Offset>; + + /// Converts the local `NaiveDate` to the timezone-aware `Date` if possible. + fn from_local_date(&self, local: &NaiveDate) -> LocalResult<Date<Self>> { + self.offset_from_local_date(local).map(|offset| { + // since FixedOffset is within +/- 1 day, the date is never affected + Date::from_utc(*local, offset) + }) + } + + /// Converts the local `NaiveDateTime` to the timezone-aware `DateTime` if possible. + fn from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<DateTime<Self>> { + self.offset_from_local_datetime(local) + .map(|offset| DateTime::from_utc(*local - offset.fix(), offset)) + } + + /// Creates the offset for given UTC `NaiveDate`. This cannot fail. + fn offset_from_utc_date(&self, utc: &NaiveDate) -> Self::Offset; + + /// Creates the offset for given UTC `NaiveDateTime`. This cannot fail. + fn offset_from_utc_datetime(&self, utc: &NaiveDateTime) -> Self::Offset; + + /// Converts the UTC `NaiveDate` to the local time. + /// The UTC is continuous and thus this cannot fail (but can give the duplicate local time). + fn from_utc_date(&self, utc: &NaiveDate) -> Date<Self> { + Date::from_utc(*utc, self.offset_from_utc_date(utc)) + } + + /// Converts the UTC `NaiveDateTime` to the local time. + /// The UTC is continuous and thus this cannot fail (but can give the duplicate local time). + fn from_utc_datetime(&self, utc: &NaiveDateTime) -> DateTime<Self> { + DateTime::from_utc(*utc, self.offset_from_utc_datetime(utc)) + } +} + +mod fixed; +#[cfg(feature = "clock")] +mod local; +mod utc; + +pub use self::fixed::FixedOffset; +#[cfg(feature = "clock")] +pub use self::local::Local; +pub use self::utc::Utc; + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn test_negative_millis() { + let dt = Utc.timestamp_millis(-1000); + assert_eq!(dt.to_string(), "1969-12-31 23:59:59 UTC"); + let dt = Utc.timestamp_millis(-7000); + assert_eq!(dt.to_string(), "1969-12-31 23:59:53 UTC"); + let dt = Utc.timestamp_millis(-7001); + assert_eq!(dt.to_string(), "1969-12-31 23:59:52.999 UTC"); + let dt = Utc.timestamp_millis(-7003); + assert_eq!(dt.to_string(), "1969-12-31 23:59:52.997 UTC"); + let dt = Utc.timestamp_millis(-999); + assert_eq!(dt.to_string(), "1969-12-31 23:59:59.001 UTC"); + let dt = Utc.timestamp_millis(-1); + assert_eq!(dt.to_string(), "1969-12-31 23:59:59.999 UTC"); + let dt = Utc.timestamp_millis(-60000); + assert_eq!(dt.to_string(), "1969-12-31 23:59:00 UTC"); + let dt = Utc.timestamp_millis(-3600000); + assert_eq!(dt.to_string(), "1969-12-31 23:00:00 UTC"); + + for (millis, expected) in &[ + (-7000, "1969-12-31 23:59:53 UTC"), + (-7001, "1969-12-31 23:59:52.999 UTC"), + (-7003, "1969-12-31 23:59:52.997 UTC"), + ] { + match Utc.timestamp_millis_opt(*millis) { + LocalResult::Single(dt) => { + assert_eq!(dt.to_string(), *expected); + } + e => panic!("Got {:?} instead of an okay answer", e), + } + } + } + + #[test] + fn test_negative_nanos() { + let dt = Utc.timestamp_nanos(-1_000_000_000); + assert_eq!(dt.to_string(), "1969-12-31 23:59:59 UTC"); + let dt = Utc.timestamp_nanos(-999_999_999); + assert_eq!(dt.to_string(), "1969-12-31 23:59:59.000000001 UTC"); + let dt = Utc.timestamp_nanos(-1); + assert_eq!(dt.to_string(), "1969-12-31 23:59:59.999999999 UTC"); + let dt = Utc.timestamp_nanos(-60_000_000_000); + assert_eq!(dt.to_string(), "1969-12-31 23:59:00 UTC"); + let dt = Utc.timestamp_nanos(-3_600_000_000_000); + assert_eq!(dt.to_string(), "1969-12-31 23:00:00 UTC"); + } + + #[test] + fn test_nanos_never_panics() { + Utc.timestamp_nanos(i64::max_value()); + Utc.timestamp_nanos(i64::default()); + Utc.timestamp_nanos(i64::min_value()); + } +} |