1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131

// This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

//! Types for resolving and manipulating time zones.
//!
//! # Fields
//!
//! In ICU4X, a [formattable time zone](TimeZoneInfo) consists of up to four different fields:
//!
//! 1. The time zone ID
//! 2. The offset from UTC
//! 3. A timestamp, as time zone names can change over time
//! 4. The zone variant, representing concepts such as Standard, Summer, Daylight, and Ramadan time
//!
//! ## Time Zone
//!
//! The time zone ID corresponds to a time zone from the time zone database. The time zone ID
//! usually corresponds to the largest city in the time zone.
//!
//! There are two mostly-interchangeable standards for time zone IDs:
//!
//! 1. IANA time zone IDs, like `"America/Chicago"`
//! 2. BCP-47 time zone IDs, like `"uschi"`
//!
//! ICU4X uses BCP-47 time zone IDs for all of its APIs. To get a BCP-47 time zone from an
//! IANA time zone, use [`TimeZoneIdMapper`].
//!
//! ## UTC Offset
//!
//! The UTC offset precisely states the time difference between the time zone in question and
//! Coordinated Universal Time (UTC).
//!
//! In localized strings, it is often rendered as "UTC-6", meaning 6 hours less than UTC (some locales
//! use the term "GMT" instead of "UTC").
//!
//! ## Timestamp
//!
//! Some time zones change names over time, such as when changing "metazone". For example, Portugal changed from
//! "Western European Time" to "Central European Time" and back in the 1990s, without changing time zone id
//! (`Europe/Lisbon`/`ptlis`). Therefore, a timestamp is needed to resolve such generic time zone names.
//!
//! It is not required to set the timestamp on [`TimeZoneInfo`]. If it is not set, some string
//! formats may be unsupported.
//!
//! ## Zone Variant
//!
//! Many zones use different names and offsets in the summer than in the winter. In ICU4X,
//! this is called the _zone variant_.
//!
//! CLDR has two zone variants, named `"standard"` and `"daylight"`. However, the mapping of these
//! variants to specific observed offsets varies from time zone to time zone, and they may not
//! consistently represent winter versus summer time.
//!
//! Note: It is not required to set the zone variant on [`TimeZoneInfo`]. If it is not set, some string
//! formats may be unsupported.
//!
//! # Examples
//!
//! ```
//! use icu::calendar::{Date, Time};
//! use icu::timezone::TimeZoneBcp47Id;
//! use icu::timezone::TimeZoneIdMapper;
//! use icu::timezone::ZoneVariant;
//! use tinystr::tinystr;
//!
//! // Parse the IANA ID
//! let id = TimeZoneIdMapper::new().iana_to_bcp47("America/Chicago");
//!
//! // Alternatively, use the BCP47 ID directly
//! let id = TimeZoneBcp47Id(tinystr!(8, "uschi"));
//!
//! // Create a TimeZoneInfo<Base> by associating the ID with an offset
//! let time_zone = id.with_offset("-0600".parse().ok());
//!
//! // Extend to a TimeZoneInfo<AtTime> by adding a local time
//! let time_zone_at_time = time_zone.at_time((Date::try_new_iso(2023, 12, 2).unwrap(), Time::midnight()));
//!
//! // Extend to a TimeZoneInfo<Full> by adding a zone variant
//! let time_zone_with_variant = time_zone_at_time.with_zone_variant(ZoneVariant::Standard);
//! ```

// https://github.com/unicode-org/icu4x/blob/main/documents/process/boilerplate.md#library-annotations
#![cfg_attr(not(any(test, feature = "std")), no_std)]
#![cfg_attr(
    not(test),
    deny(
        clippy::indexing_slicing,
        clippy::unwrap_used,
        clippy::expect_used,
        clippy::panic,
        clippy::exhaustive_structs,
        clippy::exhaustive_enums,
        missing_debug_implementations,
    )
)]
#![warn(missing_docs)]

extern crate alloc;

mod error;
mod ids;
pub mod provider;
pub mod scaffold;
mod time_zone;
mod types;
mod windows_tz;
mod zone_offset;
mod zoned_datetime;

#[cfg(feature = "ixdtf")]
mod ixdtf;
#[cfg(feature = "ixdtf")]
pub use self::ixdtf::IxdtfParser;

pub use error::InvalidOffsetError;
pub use ids::{
    TimeZoneIdMapper, TimeZoneIdMapperBorrowed, TimeZoneIdMapperWithFastCanonicalization,
    TimeZoneIdMapperWithFastCanonicalizationBorrowed,
};
pub use provider::TimeZoneBcp47Id;
pub use time_zone::models;
pub use time_zone::TimeZoneInfo;
pub use time_zone::TimeZoneModel;
pub use types::{UtcOffset, ZoneVariant};
pub use windows_tz::{WindowsTimeZoneMapper, WindowsTimeZoneMapperBorrowed};
pub use zone_offset::{ZoneOffsetCalculator, ZoneOffsets};
pub use zoned_datetime::CustomZonedDateTime;

#[cfg(all(feature = "ixdtf", feature = "compiled_data"))]
pub use crate::ixdtf::ParseError;