1// This is a part of Chrono.
2// See README.md and LICENSE.txt for details.
3
4//! The time zone which has a fixed offset from UTC.
5
6use core::fmt;
7use core::str::FromStr;
8
9#[cfg(any(feature = "rkyv", feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
10use rkyv::{Archive, Deserialize, Serialize};
11
12use super::{MappedLocalTime, Offset, TimeZone};
13use crate::format::{scan, ParseError, OUT_OF_RANGE};
14use crate::naive::{NaiveDate, NaiveDateTime};
15
16/// The time zone with fixed offset, from UTC-23:59:59 to UTC+23:59:59.
17///
18/// Using the [`TimeZone`](./trait.TimeZone.html) methods
19/// on a `FixedOffset` struct is the preferred way to construct
20/// `DateTime<FixedOffset>` instances. See the [`east_opt`](#method.east_opt) and
21/// [`west_opt`](#method.west_opt) methods for examples.
22#[derive(PartialEq, Eq, Hash, Copy, Clone)]
23#[cfg_attr(
24 any(feature = "rkyv", feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
25 derive(Archive, Deserialize, Serialize),
26 archive(compare(PartialEq)),
27 archive_attr(derive(Clone, Copy, PartialEq, Eq, Hash, Debug))
28)]
29#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
30pub struct FixedOffset {
31 local_minus_utc: i32,
32}
33
34impl FixedOffset {
35 /// Makes a new `FixedOffset` for the Eastern Hemisphere with given timezone difference.
36 /// The negative `secs` means the Western Hemisphere.
37 ///
38 /// Panics on the out-of-bound `secs`.
39 #[deprecated(since = "0.4.23", note = "use `east_opt()` instead")]
40 #[must_use]
41 pub fn east(secs: i32) -> FixedOffset {
42 FixedOffset::east_opt(secs).expect("FixedOffset::east out of bounds")
43 }
44
45 /// Makes a new `FixedOffset` for the Eastern Hemisphere with given timezone difference.
46 /// The negative `secs` means the Western Hemisphere.
47 ///
48 /// Returns `None` on the out-of-bound `secs`.
49 ///
50 /// # Example
51 ///
52 /// ```
53 /// # #[cfg(feature = "alloc")] {
54 /// use chrono::{FixedOffset, TimeZone};
55 /// let hour = 3600;
56 /// let datetime =
57 /// FixedOffset::east_opt(5 * hour).unwrap().with_ymd_and_hms(2016, 11, 08, 0, 0, 0).unwrap();
58 /// assert_eq!(&datetime.to_rfc3339(), "2016-11-08T00:00:00+05:00")
59 /// # }
60 /// ```
61 #[must_use]
62 pub const fn east_opt(secs: i32) -> Option<FixedOffset> {
63 if -86_400 < secs && secs < 86_400 {
64 Some(FixedOffset { local_minus_utc: secs })
65 } else {
66 None
67 }
68 }
69
70 /// Makes a new `FixedOffset` for the Western Hemisphere with given timezone difference.
71 /// The negative `secs` means the Eastern Hemisphere.
72 ///
73 /// Panics on the out-of-bound `secs`.
74 #[deprecated(since = "0.4.23", note = "use `west_opt()` instead")]
75 #[must_use]
76 pub fn west(secs: i32) -> FixedOffset {
77 FixedOffset::west_opt(secs).expect("FixedOffset::west out of bounds")
78 }
79
80 /// Makes a new `FixedOffset` for the Western Hemisphere with given timezone difference.
81 /// The negative `secs` means the Eastern Hemisphere.
82 ///
83 /// Returns `None` on the out-of-bound `secs`.
84 ///
85 /// # Example
86 ///
87 /// ```
88 /// # #[cfg(feature = "alloc")] {
89 /// use chrono::{FixedOffset, TimeZone};
90 /// let hour = 3600;
91 /// let datetime =
92 /// FixedOffset::west_opt(5 * hour).unwrap().with_ymd_and_hms(2016, 11, 08, 0, 0, 0).unwrap();
93 /// assert_eq!(&datetime.to_rfc3339(), "2016-11-08T00:00:00-05:00")
94 /// # }
95 /// ```
96 #[must_use]
97 pub const fn west_opt(secs: i32) -> Option<FixedOffset> {
98 if -86_400 < secs && secs < 86_400 {
99 Some(FixedOffset { local_minus_utc: -secs })
100 } else {
101 None
102 }
103 }
104
105 /// Returns the number of seconds to add to convert from UTC to the local time.
106 #[inline]
107 pub const fn local_minus_utc(&self) -> i32 {
108 self.local_minus_utc
109 }
110
111 /// Returns the number of seconds to add to convert from the local time to UTC.
112 #[inline]
113 pub const fn utc_minus_local(&self) -> i32 {
114 -self.local_minus_utc
115 }
116}
117
118/// Parsing a `str` into a `FixedOffset` uses the format [`%z`](crate::format::strftime).
119impl FromStr for FixedOffset {
120 type Err = ParseError;
121 fn from_str(s: &str) -> Result<Self, Self::Err> {
122 let (_, offset: i32) = scan::timezone_offset(s, consume_colon:scan::colon_or_space, allow_zulu:false, allow_missing_minutes:false, allow_tz_minus_sign:true)?;
123 Self::east_opt(offset).ok_or(OUT_OF_RANGE)
124 }
125}
126
127impl TimeZone for FixedOffset {
128 type Offset = FixedOffset;
129
130 fn from_offset(offset: &FixedOffset) -> FixedOffset {
131 *offset
132 }
133
134 fn offset_from_local_date(&self, _local: &NaiveDate) -> MappedLocalTime<FixedOffset> {
135 MappedLocalTime::Single(*self)
136 }
137 fn offset_from_local_datetime(&self, _local: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
138 MappedLocalTime::Single(*self)
139 }
140
141 fn offset_from_utc_date(&self, _utc: &NaiveDate) -> FixedOffset {
142 *self
143 }
144 fn offset_from_utc_datetime(&self, _utc: &NaiveDateTime) -> FixedOffset {
145 *self
146 }
147}
148
149impl Offset for FixedOffset {
150 fn fix(&self) -> FixedOffset {
151 *self
152 }
153}
154
155impl fmt::Debug for FixedOffset {
156 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
157 let offset: i32 = self.local_minus_utc;
158 let (sign: char, offset: i32) = if offset < 0 { ('-', -offset) } else { ('+', offset) };
159 let sec: i32 = offset.rem_euclid(60);
160 let mins: i32 = offset.div_euclid(60);
161 let min: i32 = mins.rem_euclid(60);
162 let hour: i32 = mins.div_euclid(60);
163 if sec == 0 {
164 write!(f, "{}{:02}:{:02}", sign, hour, min)
165 } else {
166 write!(f, "{}{:02}:{:02}:{:02}", sign, hour, min, sec)
167 }
168 }
169}
170
171impl fmt::Display for FixedOffset {
172 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
173 fmt::Debug::fmt(self, f)
174 }
175}
176
177#[cfg(all(feature = "arbitrary", feature = "std"))]
178impl arbitrary::Arbitrary<'_> for FixedOffset {
179 fn arbitrary(u: &mut arbitrary::Unstructured) -> arbitrary::Result<FixedOffset> {
180 let secs = u.int_in_range(-86_399..=86_399)?;
181 let fixed_offset = FixedOffset::east_opt(secs)
182 .expect("Could not generate a valid chrono::FixedOffset. It looks like implementation of Arbitrary for FixedOffset is erroneous.");
183 Ok(fixed_offset)
184 }
185}
186
187#[cfg(test)]
188mod tests {
189 use super::FixedOffset;
190 use crate::offset::TimeZone;
191 use std::str::FromStr;
192
193 #[test]
194 fn test_date_extreme_offset() {
195 // starting from 0.3 we don't have an offset exceeding one day.
196 // this makes everything easier!
197 let offset = FixedOffset::east_opt(86399).unwrap();
198 assert_eq!(
199 format!("{:?}", offset.with_ymd_and_hms(2012, 2, 29, 5, 6, 7).unwrap()),
200 "2012-02-29T05:06:07+23:59:59"
201 );
202 let offset = FixedOffset::east_opt(-86399).unwrap();
203 assert_eq!(
204 format!("{:?}", offset.with_ymd_and_hms(2012, 2, 29, 5, 6, 7).unwrap()),
205 "2012-02-29T05:06:07-23:59:59"
206 );
207 let offset = FixedOffset::west_opt(86399).unwrap();
208 assert_eq!(
209 format!("{:?}", offset.with_ymd_and_hms(2012, 3, 4, 5, 6, 7).unwrap()),
210 "2012-03-04T05:06:07-23:59:59"
211 );
212 let offset = FixedOffset::west_opt(-86399).unwrap();
213 assert_eq!(
214 format!("{:?}", offset.with_ymd_and_hms(2012, 3, 4, 5, 6, 7).unwrap()),
215 "2012-03-04T05:06:07+23:59:59"
216 );
217 }
218
219 #[test]
220 fn test_parse_offset() {
221 let offset = FixedOffset::from_str("-0500").unwrap();
222 assert_eq!(offset.local_minus_utc, -5 * 3600);
223 let offset = FixedOffset::from_str("-08:00").unwrap();
224 assert_eq!(offset.local_minus_utc, -8 * 3600);
225 let offset = FixedOffset::from_str("+06:30").unwrap();
226 assert_eq!(offset.local_minus_utc, (6 * 3600) + 1800);
227 }
228
229 #[test]
230 #[cfg(feature = "rkyv-validation")]
231 fn test_rkyv_validation() {
232 let offset = FixedOffset::from_str("-0500").unwrap();
233 let bytes = rkyv::to_bytes::<_, 4>(&offset).unwrap();
234 assert_eq!(rkyv::from_bytes::<FixedOffset>(&bytes).unwrap(), offset);
235 }
236}
237