// This is a part of rust-chrono.
// Copyright (c) 2014-2015, Kang Seonghoon.
// See README.md and LICENSE.txt for details.
//! # Chrono 0.2.25
//!
//! Date and time handling for Rust. (also known as `rust-chrono`)
//! It aims to be a feature-complete superset of
//! the [time](https://github.com/rust-lang-deprecated/time) library.
//! In particular,
//!
//! * Chrono strictly adheres to ISO 8601.
//! * Chrono is timezone-aware by default, with separate timezone-naive types.
//! * Chrono is space-optimal and (while not being the primary goal) reasonably efficient.
//!
//! There were several previous attempts to bring a good date and time library to Rust,
//! which Chrono builts upon and should acknowledge:
//!
//! * [Initial research on
//! the wiki](https://github.com/rust-lang/rust-wiki-backup/blob/master/Lib-datetime.md)
//! * Dietrich Epp's [datetime-rs](https://github.com/depp/datetime-rs)
//! * Luis de Bethencourt's [rust-datetime](https://github.com/luisbg/rust-datetime)
//!
//! ## Usage
//!
//! Put this in your `Cargo.toml`:
//!
//! ```toml
//! [dependencies]
//! chrono = "0.2"
//! ```
//!
//! Or, if you want [Serde](https://github.com/serde-rs/serde) or
//! [rustc-serialize](https://github.com/rust-lang-nursery/rustc-serialize) support,
//! include the features like this:
//!
//! ```toml
//! [dependencies]
//! chrono = { version = "0.2", features = ["serde", "rustc-serialize"] }
//! ```
//!
//! Then put this in your crate root:
//!
//! ```rust
//! extern crate chrono;
//! ```
//!
//! ## Overview
//!
//! ### Duration
//!
//! [**`Duration`**](./struct.Duration.html)
//! represents the magnitude of a time span. `Duration` used to be provided by Chrono.
//! It has been moved to the `time` crate as the
//! [`time::Duration`](https://doc.rust-lang.org/time/time/struct.Duration.html) type, but is
//! still re-exported from Chrono.
//!
//! ### Date and Time
//!
//! Chrono provides a
//! [**`DateTime`**](./datetime/struct.DateTime.html)
//! type to represent a date and a time in a timezone.
//!
//! For more abstract moment-in-time tracking such as internal timekeeping
//! that is unconcerned with timezones, consider
//! [`time::SystemTime`](https://doc.rust-lang.org/std/time/struct.SystemTime.html),
//! which tracks your system clock, or
//! [`time::Instant`](https://doc.rust-lang.org/std/time/struct.Instant.html), which
//! is an opaque but monotonically-increasing representation of a moment in time.
//!
//! `DateTime` is timezone-aware and must be constructed from
//! the [**`TimeZone`**](./offset/trait.TimeZone.html) object,
//! which defines how the local date is converted to and back from the UTC date.
//! There are three well-known `TimeZone` implementations:
//!
//! * [**`UTC`**](./offset/utc/struct.UTC.html) specifies the UTC time zone. It is most efficient.
//!
//! * [**`Local`**](./offset/local/struct.Local.html) specifies the system local time zone.
//!
//! * [**`FixedOffset`**](./offset/fixed/struct.FixedOffset.html) specifies
//! an arbitrary, fixed time zone such as UTC+09:00 or UTC-10:30.
//! This often results from the parsed textual date and time.
//! Since it stores the most information and does not depend on the system environment,
//! you would want to normalize other `TimeZone`s into this type.
//!
//! `DateTime`s with different `TimeZone` types are distinct and do not mix,
//! but can be converted to each other using
//! the [`DateTime::with_timezone`](./datetime/struct.DateTime.html#method.with_timezone) method.
//!
//! You can get the current date and time in the UTC time zone
//! ([`UTC::now()`](./offset/utc/struct.UTC.html#method.now))
//! or in the local time zone
//! ([`Local::now()`](./offset/local/struct.Local.html#method.now)).
//!
//! ~~~~ {.rust}
//! use chrono::*;
//!
//! let utc: DateTime<UTC> = UTC::now(); // e.g. `2014-11-28T12:45:59.324310806Z`
//! let local: DateTime<Local> = Local::now(); // e.g. `2014-11-28T21:45:59.324310806+09:00`
//! # let _ = utc; let _ = local;
//! ~~~~
//!
//! Alternatively, you can create your own date and time.
//! This is a bit verbose due to Rust's lack of function and method overloading,
//! but in turn we get a rich combination of initialization methods.
//!
//! ~~~~ {.rust}
//! use chrono::*;
//!
//! let dt = UTC.ymd(2014, 7, 8).and_hms(9, 10, 11); // `2014-07-08T09:10:11Z`
//! // July 8 is 188th day of the year 2014 (`o` for "ordinal")
//! assert_eq!(dt, UTC.yo(2014, 189).and_hms(9, 10, 11));
//! // July 8 is Tuesday in ISO week 28 of the year 2014.
//! assert_eq!(dt, UTC.isoywd(2014, 28, Weekday::Tue).and_hms(9, 10, 11));
//!
//! let dt = UTC.ymd(2014, 7, 8).and_hms_milli(9, 10, 11, 12); // `2014-07-08T09:10:11.012Z`
//! assert_eq!(dt, UTC.ymd(2014, 7, 8).and_hms_micro(9, 10, 11, 12_000));
//! assert_eq!(dt, UTC.ymd(2014, 7, 8).and_hms_nano(9, 10, 11, 12_000_000));
//!
//! // dynamic verification
//! assert_eq!(UTC.ymd_opt(2014, 7, 8).and_hms_opt(21, 15, 33),
//! LocalResult::Single(UTC.ymd(2014, 7, 8).and_hms(21, 15, 33)));
//! assert_eq!(UTC.ymd_opt(2014, 7, 8).and_hms_opt(80, 15, 33), LocalResult::None);
//! assert_eq!(UTC.ymd_opt(2014, 7, 38).and_hms_opt(21, 15, 33), LocalResult::None);
//!
//! // other time zone objects can be used to construct a local datetime.
//! // obviously, `local_dt` is normally different from `dt`, but `fixed_dt` should be identical.
//! let local_dt = Local.ymd(2014, 7, 8).and_hms_milli(9, 10, 11, 12);
//! let fixed_dt = FixedOffset::east(9 * 3600).ymd(2014, 7, 8).and_hms_milli(18, 10, 11, 12);
//! assert_eq!(dt, fixed_dt);
//! # let _ = local_dt;
//! ~~~~
//!
//! Various properties are available to the date and time, and can be altered individually.
//! Most of them are defined in the traits [`Datelike`](./trait.Datelike.html) and
//! [`Timelike`](./trait.Timelike.html) which you should `use` before.
//! Addition and subtraction is also supported.
//! The following illustrates most supported operations to the date and time:
//!
//! ~~~~ {.rust}
//! use chrono::*;
//!
//! # /* we intentionally fake the datetime...
//! // assume this returned `2014-11-28T21:45:59.324310806+09:00`:
//! let dt = Local::now();
//! # */ // up to here. we now define a fixed datetime for the illustrative purpose.
//! # let dt = FixedOffset::east(9*3600).ymd(2014, 11, 28).and_hms_nano(21, 45, 59, 324310806);
//!
//! // property accessors
//! assert_eq!((dt.year(), dt.month(), dt.day()), (2014, 11, 28));
//! assert_eq!((dt.month0(), dt.day0()), (10, 27)); // for unfortunate souls
//! assert_eq!((dt.hour(), dt.minute(), dt.second()), (21, 45, 59));
//! assert_eq!(dt.weekday(), Weekday::Fri);
//! assert_eq!(dt.weekday().number_from_monday(), 5); // Mon=1, ..., Sat=7
//! assert_eq!(dt.ordinal(), 332); // the day of year
//! assert_eq!(dt.num_days_from_ce(), 735565); // the number of days from and including Jan 1, 1
//!
//! // time zone accessor and manipulation
//! assert_eq!(dt.offset().local_minus_utc(), Duration::hours(9));
//! assert_eq!(dt.timezone(), FixedOffset::east(9 * 3600));
//! assert_eq!(dt.with_timezone(&UTC), UTC.ymd(2014, 11, 28).and_hms_nano(12, 45, 59, 324310806));
//!
//! // a sample of property manipulations (validates dynamically)
//! assert_eq!(dt.with_day(29).unwrap().weekday(), Weekday::Sat); // 2014-11-29 is Saturday
//! assert_eq!(dt.with_day(32), None);
//! assert_eq!(dt.with_year(-300).unwrap().num_days_from_ce(), -109606); // November 29, 301 BCE
//!
//! // arithmetic operations
//! assert_eq!(UTC.ymd(2014, 11, 14).and_hms(8, 9, 10) - UTC.ymd(2014, 11, 14).and_hms(10, 9, 8),
//! Duration::seconds(-2 * 3600 + 2));
//! assert_eq!(UTC.ymd(1970, 1, 1).and_hms(0, 0, 0) + Duration::seconds(1_000_000_000),
//! UTC.ymd(2001, 9, 9).and_hms(1, 46, 40));
//! assert_eq!(UTC.ymd(1970, 1, 1).and_hms(0, 0, 0) - Duration::seconds(1_000_000_000),
//! UTC.ymd(1938, 4, 24).and_hms(22, 13, 20));
//! ~~~~
//!
//! Formatting is done via the [`format`](./datetime/struct.DateTime.html#method.format) method,
//! which format is equivalent to the familiar `strftime` format.
//! (See the [`format::strftime` module documentation](./format/strftime/index.html#specifiers)
//! for full syntax.)
//!
//! The default `to_string` method and `{:?}` specifier also give a reasonable representation.
//! Chrono also provides [`to_rfc2822`](./datetime/struct.DateTime.html#method.to_rfc2822) and
//! [`to_rfc3339`](./datetime/struct.DateTime.html#method.to_rfc3339) methods
//! for well-known formats.
//!
//! ~~~~ {.rust}
//! use chrono::*;
//!
//! let dt = UTC.ymd(2014, 11, 28).and_hms(12, 0, 9);
//! assert_eq!(dt.format("%Y-%m-%d %H:%M:%S").to_string(), "2014-11-28 12:00:09");
//! assert_eq!(dt.format("%a %b %e %T %Y").to_string(), "Fri Nov 28 12:00:09 2014");
//! assert_eq!(dt.format("%a %b %e %T %Y").to_string(), dt.format("%c").to_string());
//!
//! assert_eq!(dt.to_string(), "2014-11-28 12:00:09 UTC");
//! assert_eq!(dt.to_rfc2822(), "Fri, 28 Nov 2014 12:00:09 +0000");
//! assert_eq!(dt.to_rfc3339(), "2014-11-28T12:00:09+00:00");
//! assert_eq!(format!("{:?}", dt), "2014-11-28T12:00:09Z");
//! ~~~~
//!
//! Parsing can be done with three methods:
//!
//! 1. The standard [`FromStr`](https://doc.rust-lang.org/std/str/trait.FromStr.html) trait
//! (and [`parse`](https://doc.rust-lang.org/std/primitive.str.html#method.parse) method
//! on a string) can be used for parsing `DateTime<FixedOffset>`, `DateTime<UTC>` and
//! `DateTime<Local>` values. This parses what the `{:?}`
//! ([`std::fmt::Debug`](https://doc.rust-lang.org/std/fmt/trait.Debug.html))
//! format specifier prints, and requires the offset to be present.
//!
//! 2. [`DateTime::parse_from_str`](./datetime/struct.DateTime.html#method.parse_from_str) parses
//! a date and time with offsets and returns `DateTime<FixedOffset>`.
//! This should be used when the offset is a part of input and the caller cannot guess that.
//! It *cannot* be used when the offset can be missing.
//! [`DateTime::parse_from_rfc2822`](./datetime/struct.DateTime.html#method.parse_from_rfc2822)
//! and
//! [`DateTime::parse_from_rfc3339`](./datetime/struct.DateTime.html#method.parse_from_rfc3339)
//! are similar but for well-known formats.
//!
//! 3. [`Offset::datetime_from_str`](./offset/trait.TimeZone.html#method.datetime_from_str) is
//! similar but returns `DateTime` of given offset.
//! When the explicit offset is missing from the input, it simply uses given offset.
//! It issues an error when the input contains an explicit offset different
//! from the current offset.
//!
//! More detailed control over the parsing process is available via
//! [`format`](./format/index.html) module.
//!
//! ~~~~ {.rust}
//! use chrono::*;
//!
//! let dt = UTC.ymd(2014, 11, 28).and_hms(12, 0, 9);
//! let fixed_dt = dt.with_timezone(&FixedOffset::east(9*3600));
//!
//! // method 1
//! assert_eq!("2014-11-28T12:00:09Z".parse::<DateTime<UTC>>(), Ok(dt.clone()));
//! assert_eq!("2014-11-28T21:00:09+09:00".parse::<DateTime<UTC>>(), Ok(dt.clone()));
//! assert_eq!("2014-11-28T21:00:09+09:00".parse::<DateTime<FixedOffset>>(), Ok(fixed_dt.clone()));
//!
//! // method 2
//! assert_eq!(DateTime::parse_from_str("2014-11-28 21:00:09 +09:00", "%Y-%m-%d %H:%M:%S %z"),
//! Ok(fixed_dt.clone()));
//! assert_eq!(DateTime::parse_from_rfc2822("Fri, 28 Nov 2014 21:00:09 +0900"),
//! Ok(fixed_dt.clone()));
//! assert_eq!(DateTime::parse_from_rfc3339("2014-11-28T21:00:09+09:00"), Ok(fixed_dt.clone()));
//!
//! // method 3
//! assert_eq!(UTC.datetime_from_str("2014-11-28 12:00:09", "%Y-%m-%d %H:%M:%S"), Ok(dt.clone()));
//! assert_eq!(UTC.datetime_from_str("Fri Nov 28 12:00:09 2014", "%a %b %e %T %Y"), Ok(dt.clone()));
//!
//! // oops, the year is missing!
//! assert!(UTC.datetime_from_str("Fri Nov 28 12:00:09", "%a %b %e %T %Y").is_err());
//! // oops, the format string does not include the year at all!
//! assert!(UTC.datetime_from_str("Fri Nov 28 12:00:09", "%a %b %e %T").is_err());
//! // oops, the weekday is incorrect!
//! assert!(UTC.datetime_from_str("Sat Nov 28 12:00:09 2014", "%a %b %e %T %Y").is_err());
//! ~~~~
//!
//! ### Individual date
//!
//! Chrono also provides an individual date type ([**`Date`**](./date/struct.Date.html)).
//! It also has time zones attached, and have to be constructed via time zones.
//! Most operations available to `DateTime` are also available to `Date` whenever appropriate.
//!
//! ~~~~ {.rust}
//! use chrono::*;
//!
//! # // these *may* fail, but only very rarely. just rerun the test if you were that unfortunate ;)
//! assert_eq!(UTC::today(), UTC::now().date());
//! assert_eq!(Local::today(), Local::now().date());
//!
//! assert_eq!(UTC.ymd(2014, 11, 28).weekday(), Weekday::Fri);
//! assert_eq!(UTC.ymd_opt(2014, 11, 31), LocalResult::None);
//! assert_eq!(UTC.ymd(2014, 11, 28).and_hms_milli(7, 8, 9, 10).format("%H%M%S").to_string(),
//! "070809");
//! ~~~~
//!
//! There is no timezone-aware `Time` due to the lack of usefulness and also the complexity.
//!
//! `DateTime` has [`date`](./datetime/struct.DateTime.html#method.date) method
//! which returns a `Date` which represents its date component.
//! There is also a [`time`](./datetime/struct.DateTime.html#method.time) method,
//! which simply returns a naive local time described below.
//!
//! ### Naive date and time
//!
//! Chrono provides naive counterparts to `Date`, (non-existent) `Time` and `DateTime`
//! as [**`NaiveDate`**](./naive/date/struct.NaiveDate.html),
//! [**`NaiveTime`**](./naive/time/struct.NaiveTime.html) and
//! [**`NaiveDateTime`**](./naive/datetime/struct.NaiveDateTime.html) respectively.
//!
//! They have almost equivalent interfaces as their timezone-aware twins,
//! but are not associated to time zones obviously and can be quite low-level.
//! They are mostly useful for building blocks for higher-level types.
//!
//! Timezone-aware `DateTime` and `Date` types have two methods returning naive versions:
//! [`naive_local`](./datetime/struct.DateTime.html#method.naive_local) returns
//! a view to the naive local time,
//! and [`naive_utc`](./datetime/struct.DateTime.html#method.naive_utc) returns
//! a view to the naive UTC time.
//!
//! ## Limitations
//!
//! Only proleptic Gregorian calendar (i.e. extended to support older dates) is supported.
//! Be very careful if you really have to deal with pre-20C dates, they can be in Julian or others.
//!
//! Date types are limited in about +/- 262,000 years from the common epoch.
//! Time types are limited in the nanosecond accuracy.
//!
//! [Leap seconds are supported in the representation but
//! Chrono doesn't try to make use of them](./naive/time/index.html#leap-second-handling).
//! (The main reason is that leap seconds are not really predictable.)
//! Almost *every* operation over the possible leap seconds will ignore them.
//! Consider using `NaiveDateTime` with the implicit TAI (International Atomic Time) scale
//! if you want.
//!
//! Chrono inherently does not support an inaccurate or partial date and time representation.
//! Any operation that can be ambiguous will return `None` in such cases.
//! For example, "a month later" of 2014-01-30 is not well-defined
//! and consequently `UTC.ymd(2014, 1, 30).with_month(2)` returns `None`.
//!
//! Advanced time zone handling is not yet supported (but is planned in 0.3).
// lib stability features as per RFC #507
extern crate time as stdtime;
extern crate num;
extern crate rustc_serialize;
extern crate serde;
pub use Duration;
pub use ;
pub use UTC;
pub use FixedOffset;
pub use Local;
pub use NaiveDate;
pub use NaiveTime;
pub use NaiveDateTime;
pub use Date;
pub use DateTime;
pub use ;
// useful throughout the codebase
/// The day of week.
///
/// The order of the days of week depends on the context.
/// (This is why this type does *not* implement `PartialOrd` or `Ord` traits.)
/// One should prefer `*_from_monday` or `*_from_sunday` methods to get the correct result.
/// Any weekday can be represented as an integer from 0 to 6, which equals to
/// [`Weekday::num_days_from_monday`](#method.num_days_from_monday) in this implementation.
/// Do not heavily depend on this though; use explicit methods whenever possible.
/// The common set of methods for date component.
/// The common set of methods for time component.