third_party/rust_crates/vendor/chrono/src/date.rs - fuchsia - Git at Google

 // This is a part of Chrono.
 // See README.md and LICENSE.txt for details.

 //! ISO 8601 calendar date with time zone.

 use std::{fmt, hash};
 use std::cmp::Ordering;
 use std::ops::{Add, Sub};
 use oldtime::Duration as OldDuration;

 use {Weekday, Datelike};
 use offset::{TimeZone, Utc};
 use naive::{self, NaiveDate, NaiveTime, IsoWeek};
 use DateTime;
 use format::{Item, DelayedFormat, StrftimeItems};

 /// ISO 8601 calendar date with time zone.
 ///
 /// This type should be considered ambiguous at best,
 /// due to the inherent lack of precision required for the time zone resolution.
 /// For serialization and deserialization uses, it is best to use `NaiveDate` instead.
 /// There are some guarantees on the usage of `Date<Tz>`:
 ///
 /// - If properly constructed via `TimeZone::ymd` and others without an error,
 ///   the corresponding local date should exist for at least a moment.
 ///   (It may still have a gap from the offset changes.)
 ///
 /// - The `TimeZone` is free to assign *any* `Offset` to the local date,
 ///   as long as that offset did occur in given day.
 ///   For example, if `2015-03-08T01:59-08:00` is followed by `2015-03-08T03:00-07:00`,
 ///   it may produce either `2015-03-08-08:00` or `2015-03-08-07:00`
 ///   but *not* `2015-03-08+00:00` and others.
 ///
 /// - Once constructed as a full `DateTime`,
 ///   `DateTime::date` and other associated methods should return those for the original `Date`.
 ///   For example, if `dt = tz.ymd(y,m,d).hms(h,n,s)` were valid, `dt.date() == tz.ymd(y,m,d)`.
 ///
 /// - The date is timezone-agnostic up to one day (i.e. practically always),
 ///   so the local date and UTC date should be equal for most cases
 ///   even though the raw calculation between `NaiveDate` and `Duration` may not.
 #[derive(Clone)]
 pub struct Date<Tz: TimeZone> {
     date: NaiveDate,
     offset: Tz::Offset,
 }

 /// The minimum possible `Date`.
 pub const MIN_DATE: Date<Utc> = Date { date: naive::MIN_DATE, offset: Utc };
 /// The maximum possible `Date`.
 pub const MAX_DATE: Date<Utc> = Date { date: naive::MAX_DATE, offset: Utc };

 impl<Tz: TimeZone> Date<Tz> {
     /// Makes a new `Date` with given *UTC* date and offset.
     /// The local date should be constructed via the `TimeZone` trait.
     //
     // note: this constructor is purposedly not named to `new` to discourage the direct usage.
     #[inline]
     pub fn from_utc(date: NaiveDate, offset: Tz::Offset) -> Date<Tz> {
         Date { date: date, offset: offset }
     }

     /// Makes a new `DateTime` from the current date and given `NaiveTime`.
     /// The offset in the current date is preserved.
     ///
     /// Panics on invalid datetime.
     #[inline]
     pub fn and_time(&self, time: NaiveTime) -> Option<DateTime<Tz>> {
         let localdt = self.naive_local().and_time(time);
         self.timezone().from_local_datetime(&localdt).single()
     }

     /// Makes a new `DateTime` from the current date, hour, minute and second.
     /// The offset in the current date is preserved.
     ///
     /// Panics on invalid hour, minute and/or second.
     #[inline]
     pub fn and_hms(&self, hour: u32, min: u32, sec: u32) -> DateTime<Tz> {
         self.and_hms_opt(hour, min, sec).expect("invalid time")
     }

     /// Makes a new `DateTime` from the current date, hour, minute and second.
     /// The offset in the current date is preserved.
     ///
     /// Returns `None` on invalid hour, minute and/or second.
     #[inline]
     pub fn and_hms_opt(&self, hour: u32, min: u32, sec: u32) -> Option<DateTime<Tz>> {
         NaiveTime::from_hms_opt(hour, min, sec).and_then(|time| self.and_time(time))
     }

     /// 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.
     ///
     /// Panics on invalid hour, minute, second and/or millisecond.
     #[inline]
     pub fn and_hms_milli(&self, hour: u32, min: u32, sec: u32, milli: u32) -> DateTime<Tz> {
         self.and_hms_milli_opt(hour, min, sec, milli).expect("invalid time")
     }

     /// 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.
     ///
     /// Returns `None` on invalid hour, minute, second and/or millisecond.
     #[inline]
     pub fn and_hms_milli_opt(&self, hour: u32, min: u32, sec: u32,
                              milli: u32) -> Option<DateTime<Tz>> {
         NaiveTime::from_hms_milli_opt(hour, min, sec, milli).and_then(|time| self.and_time(time))
     }

     /// 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.
     ///
     /// Panics on invalid hour, minute, second and/or microsecond.
     #[inline]
     pub fn and_hms_micro(&self, hour: u32, min: u32, sec: u32, micro: u32) -> DateTime<Tz> {
         self.and_hms_micro_opt(hour, min, sec, micro).expect("invalid time")
     }

     /// 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.
     ///
     /// Returns `None` on invalid hour, minute, second and/or microsecond.
     #[inline]
     pub fn and_hms_micro_opt(&self, hour: u32, min: u32, sec: u32,
                              micro: u32) -> Option<DateTime<Tz>> {
         NaiveTime::from_hms_micro_opt(hour, min, sec, micro).and_then(|time| self.and_time(time))
     }

     /// 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.
     ///
     /// Panics on invalid hour, minute, second and/or nanosecond.
     #[inline]
     pub fn and_hms_nano(&self, hour: u32, min: u32, sec: u32, nano: u32) -> DateTime<Tz> {
         self.and_hms_nano_opt(hour, min, sec, nano).expect("invalid time")
     }

     /// 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.
     ///
     /// Returns `None` on invalid hour, minute, second and/or nanosecond.
     #[inline]
     pub fn and_hms_nano_opt(&self, hour: u32, min: u32, sec: u32,
                             nano: u32) -> Option<DateTime<Tz>> {
         NaiveTime::from_hms_nano_opt(hour, min, sec, nano).and_then(|time| self.and_time(time))
     }

     /// Makes a new `Date` for the next date.
     ///
     /// Panics when `self` is the last representable date.
     #[inline]
     pub fn succ(&self) -> Date<Tz> {
         self.succ_opt().expect("out of bound")
     }

     /// Makes a new `Date` for the next date.
     ///
     /// Returns `None` when `self` is the last representable date.
     #[inline]
     pub fn succ_opt(&self) -> Option<Date<Tz>> {
         self.date.succ_opt().map(|date| Date::from_utc(date, self.offset.clone()))
     }

     /// Makes a new `Date` for the prior date.
     ///
     /// Panics when `self` is the first representable date.
     #[inline]
     pub fn pred(&self) -> Date<Tz> {
         self.pred_opt().expect("out of bound")
     }

     /// Makes a new `Date` for the prior date.
     ///
     /// Returns `None` when `self` is the first representable date.
     #[inline]
     pub fn pred_opt(&self) -> Option<Date<Tz>> {
         self.date.pred_opt().map(|date| Date::from_utc(date, self.offset.clone()))
     }

     /// Retrieves an associated offset from UTC.
     #[inline]
     pub fn offset(&self) -> &Tz::Offset {
         &self.offset
     }

     /// Retrieves an associated time zone.
     #[inline]
     pub fn timezone(&self) -> Tz {
         TimeZone::from_offset(&self.offset)
     }

     /// Changes the associated time zone.
     /// This does not change the actual `Date` (but will change the string representation).
     #[inline]
     pub fn with_timezone<Tz2: TimeZone>(&self, tz: &Tz2) -> Date<Tz2> {
         tz.from_utc_date(&self.date)
     }

     /// Adds given `Duration` to the current date.
     ///
     /// Returns `None` when it will result in overflow.
     #[inline]
     pub fn checked_add_signed(self, rhs: OldDuration) -> Option<Date<Tz>> {
         let date = try_opt!(self.date.checked_add_signed(rhs));
         Some(Date { date: date, offset: self.offset })
     }

     /// Subtracts given `Duration` from the current date.
     ///
     /// Returns `None` when it will result in overflow.
     #[inline]
     pub fn checked_sub_signed(self, rhs: OldDuration) -> Option<Date<Tz>> {
         let date = try_opt!(self.date.checked_sub_signed(rhs));
         Some(Date { date: date, offset: self.offset })
     }

     /// Subtracts another `Date` from the current date.
     /// Returns a `Duration` of integral numbers.
     ///
     /// This does not overflow or underflow at all,
     /// as all possible output fits in the range of `Duration`.
     #[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
     #[inline]
     pub fn signed_duration_since<Tz2: TimeZone>(self, rhs: Date<Tz2>) -> OldDuration {
         self.date.signed_duration_since(rhs.date)
     }

     /// Returns a view to the naive UTC date.
     #[inline]
     pub fn naive_utc(&self) -> NaiveDate {
         self.date
     }

     /// Returns a view to the naive local date.
     ///
     /// This is technically same to [`naive_utc`](#method.naive_utc)
     /// because the offset is restricted to never exceed one day,
     /// but provided for the consistency.
     #[inline]
     pub fn naive_local(&self) -> NaiveDate {
         self.date
     }
 }

 /// Maps the local date to other date with given conversion function.
 fn map_local<Tz: TimeZone, F>(d: &Date<Tz>, mut f: F) -> Option<Date<Tz>>
         where F: FnMut(NaiveDate) -> Option<NaiveDate> {
     f(d.naive_local()).and_then(|date| d.timezone().from_local_date(&date).single())
 }

 impl<Tz: TimeZone> Date<Tz> where Tz::Offset: fmt::Display {
     /// Formats the date with the specified formatting items.
     #[inline]
     pub fn format_with_items<'a, I>(&self, items: I) -> DelayedFormat<I>
             where I: Iterator<Item=Item<'a>> + Clone {
         DelayedFormat::new_with_offset(Some(self.naive_local()), None, &self.offset, items)
     }

     /// Formats the date with the specified format string.
     /// See the [`format::strftime` module](./format/strftime/index.html)
     /// on the supported escape sequences.
     #[inline]
     pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
         self.format_with_items(StrftimeItems::new(fmt))
     }
 }

 impl<Tz: TimeZone> Datelike for Date<Tz> {
     #[inline] fn year(&self) -> i32 { self.naive_local().year() }
     #[inline] fn month(&self) -> u32 { self.naive_local().month() }
     #[inline] fn month0(&self) -> u32 { self.naive_local().month0() }
     #[inline] fn day(&self) -> u32 { self.naive_local().day() }
     #[inline] fn day0(&self) -> u32 { self.naive_local().day0() }
     #[inline] fn ordinal(&self) -> u32 { self.naive_local().ordinal() }
     #[inline] fn ordinal0(&self) -> u32 { self.naive_local().ordinal0() }
     #[inline] fn weekday(&self) -> Weekday { self.naive_local().weekday() }
     #[inline] fn iso_week(&self) -> IsoWeek { self.naive_local().iso_week() }

     #[inline]
     fn with_year(&self, year: i32) -> Option<Date<Tz>> {
         map_local(self, |date| date.with_year(year))
     }

     #[inline]
     fn with_month(&self, month: u32) -> Option<Date<Tz>> {
         map_local(self, |date| date.with_month(month))
     }

     #[inline]
     fn with_month0(&self, month0: u32) -> Option<Date<Tz>> {
         map_local(self, |date| date.with_month0(month0))
     }

     #[inline]
     fn with_day(&self, day: u32) -> Option<Date<Tz>> {
         map_local(self, |date| date.with_day(day))
     }

     #[inline]
     fn with_day0(&self, day0: u32) -> Option<Date<Tz>> {
         map_local(self, |date| date.with_day0(day0))
     }

     #[inline]
     fn with_ordinal(&self, ordinal: u32) -> Option<Date<Tz>> {
         map_local(self, |date| date.with_ordinal(ordinal))
     }

     #[inline]
     fn with_ordinal0(&self, ordinal0: u32) -> Option<Date<Tz>> {
         map_local(self, |date| date.with_ordinal0(ordinal0))
     }
 }

 // we need them as automatic impls cannot handle associated types
 impl<Tz: TimeZone> Copy for Date<Tz> where <Tz as TimeZone>::Offset: Copy {}
 unsafe impl<Tz: TimeZone> Send for Date<Tz> where <Tz as TimeZone>::Offset: Send {}

 impl<Tz: TimeZone, Tz2: TimeZone> PartialEq<Date<Tz2>> for Date<Tz> {
     fn eq(&self, other: &Date<Tz2>) -> bool { self.date == other.date }
 }

 impl<Tz: TimeZone> Eq for Date<Tz> {
 }

 impl<Tz: TimeZone> PartialOrd for Date<Tz> {
     fn partial_cmp(&self, other: &Date<Tz>) -> Option<Ordering> {
         self.date.partial_cmp(&other.date)
     }
 }

 impl<Tz: TimeZone> Ord for Date<Tz> {
     fn cmp(&self, other: &Date<Tz>) -> Ordering { self.date.cmp(&other.date) }
 }

 impl<Tz: TimeZone> hash::Hash for Date<Tz> {
     fn hash<H: hash::Hasher>(&self, state: &mut H) { self.date.hash(state) }
 }

 impl<Tz: TimeZone> Add<OldDuration> for Date<Tz> {
     type Output = Date<Tz>;

     #[inline]
     fn add(self, rhs: OldDuration) -> Date<Tz> {
         self.checked_add_signed(rhs).expect("`Date + Duration` overflowed")
     }
 }

 impl<Tz: TimeZone> Sub<OldDuration> for Date<Tz> {
     type Output = Date<Tz>;

     #[inline]
     fn sub(self, rhs: OldDuration) -> Date<Tz> {
         self.checked_sub_signed(rhs).expect("`Date - Duration` overflowed")
     }
 }

 impl<Tz: TimeZone> Sub<Date<Tz>> for Date<Tz> {
     type Output = OldDuration;

     #[inline]
     fn sub(self, rhs: Date<Tz>) -> OldDuration {
         self.signed_duration_since(rhs)
     }
 }

 impl<Tz: TimeZone> fmt::Debug for Date<Tz> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{:?}{:?}", self.naive_local(), self.offset)
     }
 }

 impl<Tz: TimeZone> fmt::Display for Date<Tz> where Tz::Offset: fmt::Display {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{}{}", self.naive_local(), self.offset)
     }
 }
	// This is a part of Chrono.
	// See README.md and LICENSE.txt for details.

	//! ISO 8601 calendar date with time zone.

	use std::{fmt, hash};
	use std::cmp::Ordering;
	use std::ops::{Add, Sub};
	use oldtime::Duration as OldDuration;

	use {Weekday, Datelike};
	use offset::{TimeZone, Utc};
	use naive::{self, NaiveDate, NaiveTime, IsoWeek};
	use DateTime;
	use format::{Item, DelayedFormat, StrftimeItems};

	/// ISO 8601 calendar date with time zone.
	///
	/// This type should be considered ambiguous at best,
	/// due to the inherent lack of precision required for the time zone resolution.
	/// For serialization and deserialization uses, it is best to use `NaiveDate` instead.
	/// There are some guarantees on the usage of `Date<Tz>`:
	///
	/// - If properly constructed via `TimeZone::ymd` and others without an error,
	/// the corresponding local date should exist for at least a moment.
	/// (It may still have a gap from the offset changes.)
	///
	/// - The `TimeZone` is free to assign any `Offset` to the local date,
	/// as long as that offset did occur in given day.
	/// For example, if `2015-03-08T01:59-08:00` is followed by `2015-03-08T03:00-07:00`,
	/// it may produce either `2015-03-08-08:00` or `2015-03-08-07:00`
	/// but not `2015-03-08+00:00` and others.
	///
	/// - Once constructed as a full `DateTime`,
	/// `DateTime::date` and other associated methods should return those for the original `Date`.
	/// For example, if `dt = tz.ymd(y,m,d).hms(h,n,s)` were valid, `dt.date() == tz.ymd(y,m,d)`.
	///
	/// - The date is timezone-agnostic up to one day (i.e. practically always),
	/// so the local date and UTC date should be equal for most cases
	/// even though the raw calculation between `NaiveDate` and `Duration` may not.
	#[derive(Clone)]
	pub struct Date<Tz: TimeZone> {
	date: NaiveDate,
	offset: Tz::Offset,
	}

	/// The minimum possible `Date`.
	pub const MIN_DATE: Date<Utc> = Date { date: naive::MIN_DATE, offset: Utc };
	/// The maximum possible `Date`.
	pub const MAX_DATE: Date<Utc> = Date { date: naive::MAX_DATE, offset: Utc };

	impl<Tz: TimeZone> Date<Tz> {
	/// Makes a new `Date` with given UTC date and offset.
	/// The local date should be constructed via the `TimeZone` trait.
	//
	// note: this constructor is purposedly not named to `new` to discourage the direct usage.
	#[inline]
	pub fn from_utc(date: NaiveDate, offset: Tz::Offset) -> Date<Tz> {
	Date { date: date, offset: offset }
	}

	/// Makes a new `DateTime` from the current date and given `NaiveTime`.
	/// The offset in the current date is preserved.
	///
	/// Panics on invalid datetime.
	#[inline]
	pub fn and_time(&self, time: NaiveTime) -> Option<DateTime<Tz>> {
	let localdt = self.naive_local().and_time(time);
	self.timezone().from_local_datetime(&localdt).single()
	}

	/// Makes a new `DateTime` from the current date, hour, minute and second.
	/// The offset in the current date is preserved.
	///
	/// Panics on invalid hour, minute and/or second.
	#[inline]
	pub fn and_hms(&self, hour: u32, min: u32, sec: u32) -> DateTime<Tz> {
	self.and_hms_opt(hour, min, sec).expect("invalid time")
	}

	/// Makes a new `DateTime` from the current date, hour, minute and second.
	/// The offset in the current date is preserved.
	///
	/// Returns `None` on invalid hour, minute and/or second.
	#[inline]
	pub fn and_hms_opt(&self, hour: u32, min: u32, sec: u32) -> Option<DateTime<Tz>> {
	NaiveTime::from_hms_opt(hour, min, sec).and_then(\|time\| self.and_time(time))
	}

	/// 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.
	///
	/// Panics on invalid hour, minute, second and/or millisecond.
	#[inline]
	pub fn and_hms_milli(&self, hour: u32, min: u32, sec: u32, milli: u32) -> DateTime<Tz> {
	self.and_hms_milli_opt(hour, min, sec, milli).expect("invalid time")
	}

	/// 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.
	///
	/// Returns `None` on invalid hour, minute, second and/or millisecond.
	#[inline]
	pub fn and_hms_milli_opt(&self, hour: u32, min: u32, sec: u32,
	milli: u32) -> Option<DateTime<Tz>> {
	NaiveTime::from_hms_milli_opt(hour, min, sec, milli).and_then(\|time\| self.and_time(time))
	}

	/// 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.
	///
	/// Panics on invalid hour, minute, second and/or microsecond.
	#[inline]
	pub fn and_hms_micro(&self, hour: u32, min: u32, sec: u32, micro: u32) -> DateTime<Tz> {
	self.and_hms_micro_opt(hour, min, sec, micro).expect("invalid time")
	}

	/// 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.
	///
	/// Returns `None` on invalid hour, minute, second and/or microsecond.
	#[inline]
	pub fn and_hms_micro_opt(&self, hour: u32, min: u32, sec: u32,
	micro: u32) -> Option<DateTime<Tz>> {
	NaiveTime::from_hms_micro_opt(hour, min, sec, micro).and_then(\|time\| self.and_time(time))
	}

	/// 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.
	///
	/// Panics on invalid hour, minute, second and/or nanosecond.
	#[inline]
	pub fn and_hms_nano(&self, hour: u32, min: u32, sec: u32, nano: u32) -> DateTime<Tz> {
	self.and_hms_nano_opt(hour, min, sec, nano).expect("invalid time")
	}

	/// 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.
	///
	/// Returns `None` on invalid hour, minute, second and/or nanosecond.
	#[inline]
	pub fn and_hms_nano_opt(&self, hour: u32, min: u32, sec: u32,
	nano: u32) -> Option<DateTime<Tz>> {
	NaiveTime::from_hms_nano_opt(hour, min, sec, nano).and_then(\|time\| self.and_time(time))
	}

	/// Makes a new `Date` for the next date.
	///
	/// Panics when `self` is the last representable date.
	#[inline]
	pub fn succ(&self) -> Date<Tz> {
	self.succ_opt().expect("out of bound")
	}

	/// Makes a new `Date` for the next date.
	///
	/// Returns `None` when `self` is the last representable date.
	#[inline]
	pub fn succ_opt(&self) -> Option<Date<Tz>> {
	self.date.succ_opt().map(\|date\| Date::from_utc(date, self.offset.clone()))
	}

	/// Makes a new `Date` for the prior date.
	///
	/// Panics when `self` is the first representable date.
	#[inline]
	pub fn pred(&self) -> Date<Tz> {
	self.pred_opt().expect("out of bound")
	}

	/// Makes a new `Date` for the prior date.
	///
	/// Returns `None` when `self` is the first representable date.
	#[inline]
	pub fn pred_opt(&self) -> Option<Date<Tz>> {
	self.date.pred_opt().map(\|date\| Date::from_utc(date, self.offset.clone()))
	}

	/// Retrieves an associated offset from UTC.
	#[inline]
	pub fn offset(&self) -> &Tz::Offset {
	&self.offset
	}

	/// Retrieves an associated time zone.
	#[inline]
	pub fn timezone(&self) -> Tz {
	TimeZone::from_offset(&self.offset)
	}

	/// Changes the associated time zone.
	/// This does not change the actual `Date` (but will change the string representation).
	#[inline]
	pub fn with_timezone<Tz2: TimeZone>(&self, tz: &Tz2) -> Date<Tz2> {
	tz.from_utc_date(&self.date)
	}

	/// Adds given `Duration` to the current date.
	///
	/// Returns `None` when it will result in overflow.
	#[inline]
	pub fn checked_add_signed(self, rhs: OldDuration) -> Option<Date<Tz>> {
	let date = try_opt!(self.date.checked_add_signed(rhs));
	Some(Date { date: date, offset: self.offset })
	}

	/// Subtracts given `Duration` from the current date.
	///
	/// Returns `None` when it will result in overflow.
	#[inline]
	pub fn checked_sub_signed(self, rhs: OldDuration) -> Option<Date<Tz>> {
	let date = try_opt!(self.date.checked_sub_signed(rhs));
	Some(Date { date: date, offset: self.offset })
	}

	/// Subtracts another `Date` from the current date.
	/// Returns a `Duration` of integral numbers.
	///
	/// This does not overflow or underflow at all,
	/// as all possible output fits in the range of `Duration`.
	#[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
	#[inline]
	pub fn signed_duration_since<Tz2: TimeZone>(self, rhs: Date<Tz2>) -> OldDuration {
	self.date.signed_duration_since(rhs.date)
	}

	/// Returns a view to the naive UTC date.
	#[inline]
	pub fn naive_utc(&self) -> NaiveDate {
	self.date
	}

	/// Returns a view to the naive local date.
	///
	/// This is technically same to [`naive_utc`](#method.naive_utc)
	/// because the offset is restricted to never exceed one day,
	/// but provided for the consistency.
	#[inline]
	pub fn naive_local(&self) -> NaiveDate {
	self.date
	}
	}

	/// Maps the local date to other date with given conversion function.
	fn map_local<Tz: TimeZone, F>(d: &Date<Tz>, mut f: F) -> Option<Date<Tz>>
	where F: FnMut(NaiveDate) -> Option<NaiveDate> {
	f(d.naive_local()).and_then(\|date\| d.timezone().from_local_date(&date).single())
	}

	impl<Tz: TimeZone> Date<Tz> where Tz::Offset: fmt::Display {
	/// Formats the date with the specified formatting items.
	#[inline]
	pub fn format_with_items<'a, I>(&self, items: I) -> DelayedFormat<I>
	where I: Iterator<Item=Item<'a>> + Clone {
	DelayedFormat::new_with_offset(Some(self.naive_local()), None, &self.offset, items)
	}

	/// Formats the date with the specified format string.
	/// See the [`format::strftime` module](./format/strftime/index.html)
	/// on the supported escape sequences.
	#[inline]
	pub fn format<'a>(&self, fmt: &'a str) -> DelayedFormat<StrftimeItems<'a>> {
	self.format_with_items(StrftimeItems::new(fmt))
	}
	}

	impl<Tz: TimeZone> Datelike for Date<Tz> {
	#[inline] fn year(&self) -> i32 { self.naive_local().year() }
	#[inline] fn month(&self) -> u32 { self.naive_local().month() }
	#[inline] fn month0(&self) -> u32 { self.naive_local().month0() }
	#[inline] fn day(&self) -> u32 { self.naive_local().day() }
	#[inline] fn day0(&self) -> u32 { self.naive_local().day0() }
	#[inline] fn ordinal(&self) -> u32 { self.naive_local().ordinal() }
	#[inline] fn ordinal0(&self) -> u32 { self.naive_local().ordinal0() }
	#[inline] fn weekday(&self) -> Weekday { self.naive_local().weekday() }
	#[inline] fn iso_week(&self) -> IsoWeek { self.naive_local().iso_week() }

	#[inline]
	fn with_year(&self, year: i32) -> Option<Date<Tz>> {
	map_local(self, \|date\| date.with_year(year))
	}

	#[inline]
	fn with_month(&self, month: u32) -> Option<Date<Tz>> {
	map_local(self, \|date\| date.with_month(month))
	}

	#[inline]
	fn with_month0(&self, month0: u32) -> Option<Date<Tz>> {
	map_local(self, \|date\| date.with_month0(month0))
	}

	#[inline]
	fn with_day(&self, day: u32) -> Option<Date<Tz>> {
	map_local(self, \|date\| date.with_day(day))
	}

	#[inline]
	fn with_day0(&self, day0: u32) -> Option<Date<Tz>> {
	map_local(self, \|date\| date.with_day0(day0))
	}

	#[inline]
	fn with_ordinal(&self, ordinal: u32) -> Option<Date<Tz>> {
	map_local(self, \|date\| date.with_ordinal(ordinal))
	}

	#[inline]
	fn with_ordinal0(&self, ordinal0: u32) -> Option<Date<Tz>> {
	map_local(self, \|date\| date.with_ordinal0(ordinal0))
	}
	}

	// we need them as automatic impls cannot handle associated types
	impl<Tz: TimeZone> Copy for Date<Tz> where <Tz as TimeZone>::Offset: Copy {}
	unsafe impl<Tz: TimeZone> Send for Date<Tz> where <Tz as TimeZone>::Offset: Send {}

	impl<Tz: TimeZone, Tz2: TimeZone> PartialEq<Date<Tz2>> for Date<Tz> {
	fn eq(&self, other: &Date<Tz2>) -> bool { self.date == other.date }
	}

	impl<Tz: TimeZone> Eq for Date<Tz> {
	}

	impl<Tz: TimeZone> PartialOrd for Date<Tz> {
	fn partial_cmp(&self, other: &Date<Tz>) -> Option<Ordering> {
	self.date.partial_cmp(&other.date)
	}
	}

	impl<Tz: TimeZone> Ord for Date<Tz> {
	fn cmp(&self, other: &Date<Tz>) -> Ordering { self.date.cmp(&other.date) }
	}

	impl<Tz: TimeZone> hash::Hash for Date<Tz> {
	fn hash<H: hash::Hasher>(&self, state: &mut H) { self.date.hash(state) }
	}

	impl<Tz: TimeZone> Add<OldDuration> for Date<Tz> {
	type Output = Date<Tz>;

	#[inline]
	fn add(self, rhs: OldDuration) -> Date<Tz> {
	self.checked_add_signed(rhs).expect("`Date + Duration` overflowed")
	}
	}

	impl<Tz: TimeZone> Sub<OldDuration> for Date<Tz> {
	type Output = Date<Tz>;

	#[inline]
	fn sub(self, rhs: OldDuration) -> Date<Tz> {
	self.checked_sub_signed(rhs).expect("`Date - Duration` overflowed")
	}
	}

	impl<Tz: TimeZone> Sub<Date<Tz>> for Date<Tz> {
	type Output = OldDuration;

	#[inline]
	fn sub(self, rhs: Date<Tz>) -> OldDuration {
	self.signed_duration_since(rhs)
	}
	}

	impl<Tz: TimeZone> fmt::Debug for Date<Tz> {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	write!(f, "{:?}{:?}", self.naive_local(), self.offset)
	}
	}

	impl<Tz: TimeZone> fmt::Display for Date<Tz> where Tz::Offset: fmt::Display {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	write!(f, "{}{}", self.naive_local(), self.offset)
	}
	}