chrono/offset/
fixed.rs

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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
// This is a part of Chrono.
// See README.md and LICENSE.txt for details.

//! The time zone which has a fixed offset from UTC.

use core::fmt;
use core::str::FromStr;

#[cfg(any(feature = "rkyv", feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
use rkyv::{Archive, Deserialize, Serialize};

use super::{MappedLocalTime, Offset, TimeZone};
use crate::format::{scan, ParseError, OUT_OF_RANGE};
use crate::naive::{NaiveDate, NaiveDateTime};

/// The time zone with fixed offset, from UTC-23:59:59 to UTC+23:59:59.
///
/// Using the [`TimeZone`](./trait.TimeZone.html) methods
/// on a `FixedOffset` struct is the preferred way to construct
/// `DateTime<FixedOffset>` instances. See the [`east_opt`](#method.east_opt) and
/// [`west_opt`](#method.west_opt) methods for examples.
#[derive(PartialEq, Eq, Hash, Copy, Clone)]
#[cfg_attr(
    any(feature = "rkyv", feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"),
    derive(Archive, Deserialize, Serialize),
    archive(compare(PartialEq)),
    archive_attr(derive(Clone, Copy, PartialEq, Eq, Hash, Debug))
)]
#[cfg_attr(feature = "rkyv-validation", archive(check_bytes))]
pub struct FixedOffset {
    local_minus_utc: i32,
}

impl FixedOffset {
    /// Makes a new `FixedOffset` for the Eastern Hemisphere with given timezone difference.
    /// The negative `secs` means the Western Hemisphere.
    ///
    /// Panics on the out-of-bound `secs`.
    #[deprecated(since = "0.4.23", note = "use `east_opt()` instead")]
    #[must_use]
    pub fn east(secs: i32) -> FixedOffset {
        FixedOffset::east_opt(secs).expect("FixedOffset::east out of bounds")
    }

    /// Makes a new `FixedOffset` for the Eastern Hemisphere with given timezone difference.
    /// The negative `secs` means the Western Hemisphere.
    ///
    /// Returns `None` on the out-of-bound `secs`.
    ///
    /// # Example
    ///
    /// ```
    /// # #[cfg(feature = "alloc")] {
    /// use chrono::{FixedOffset, TimeZone};
    /// let hour = 3600;
    /// let datetime =
    ///     FixedOffset::east_opt(5 * hour).unwrap().with_ymd_and_hms(2016, 11, 08, 0, 0, 0).unwrap();
    /// assert_eq!(&datetime.to_rfc3339(), "2016-11-08T00:00:00+05:00")
    /// # }
    /// ```
    #[must_use]
    pub const fn east_opt(secs: i32) -> Option<FixedOffset> {
        if -86_400 < secs && secs < 86_400 {
            Some(FixedOffset { local_minus_utc: secs })
        } else {
            None
        }
    }

    /// Makes a new `FixedOffset` for the Western Hemisphere with given timezone difference.
    /// The negative `secs` means the Eastern Hemisphere.
    ///
    /// Panics on the out-of-bound `secs`.
    #[deprecated(since = "0.4.23", note = "use `west_opt()` instead")]
    #[must_use]
    pub fn west(secs: i32) -> FixedOffset {
        FixedOffset::west_opt(secs).expect("FixedOffset::west out of bounds")
    }

    /// Makes a new `FixedOffset` for the Western Hemisphere with given timezone difference.
    /// The negative `secs` means the Eastern Hemisphere.
    ///
    /// Returns `None` on the out-of-bound `secs`.
    ///
    /// # Example
    ///
    /// ```
    /// # #[cfg(feature = "alloc")] {
    /// use chrono::{FixedOffset, TimeZone};
    /// let hour = 3600;
    /// let datetime =
    ///     FixedOffset::west_opt(5 * hour).unwrap().with_ymd_and_hms(2016, 11, 08, 0, 0, 0).unwrap();
    /// assert_eq!(&datetime.to_rfc3339(), "2016-11-08T00:00:00-05:00")
    /// # }
    /// ```
    #[must_use]
    pub const fn west_opt(secs: i32) -> Option<FixedOffset> {
        if -86_400 < secs && secs < 86_400 {
            Some(FixedOffset { local_minus_utc: -secs })
        } else {
            None
        }
    }

    /// Returns the number of seconds to add to convert from UTC to the local time.
    #[inline]
    pub const fn local_minus_utc(&self) -> i32 {
        self.local_minus_utc
    }

    /// Returns the number of seconds to add to convert from the local time to UTC.
    #[inline]
    pub const fn utc_minus_local(&self) -> i32 {
        -self.local_minus_utc
    }
}

/// Parsing a `str` into a `FixedOffset` uses the format [`%z`](crate::format::strftime).
impl FromStr for FixedOffset {
    type Err = ParseError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let (_, offset) = scan::timezone_offset(s, scan::colon_or_space, false, false, true)?;
        Self::east_opt(offset).ok_or(OUT_OF_RANGE)
    }
}

impl TimeZone for FixedOffset {
    type Offset = FixedOffset;

    fn from_offset(offset: &FixedOffset) -> FixedOffset {
        *offset
    }

    fn offset_from_local_date(&self, _local: &NaiveDate) -> MappedLocalTime<FixedOffset> {
        MappedLocalTime::Single(*self)
    }
    fn offset_from_local_datetime(&self, _local: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
        MappedLocalTime::Single(*self)
    }

    fn offset_from_utc_date(&self, _utc: &NaiveDate) -> FixedOffset {
        *self
    }
    fn offset_from_utc_datetime(&self, _utc: &NaiveDateTime) -> FixedOffset {
        *self
    }
}

impl Offset for FixedOffset {
    fn fix(&self) -> FixedOffset {
        *self
    }
}

impl fmt::Debug for FixedOffset {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let offset = self.local_minus_utc;
        let (sign, offset) = if offset < 0 { ('-', -offset) } else { ('+', offset) };
        let sec = offset.rem_euclid(60);
        let mins = offset.div_euclid(60);
        let min = mins.rem_euclid(60);
        let hour = mins.div_euclid(60);
        if sec == 0 {
            write!(f, "{}{:02}:{:02}", sign, hour, min)
        } else {
            write!(f, "{}{:02}:{:02}:{:02}", sign, hour, min, sec)
        }
    }
}

impl fmt::Display for FixedOffset {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        fmt::Debug::fmt(self, f)
    }
}

#[cfg(all(feature = "arbitrary", feature = "std"))]
impl arbitrary::Arbitrary<'_> for FixedOffset {
    fn arbitrary(u: &mut arbitrary::Unstructured) -> arbitrary::Result<FixedOffset> {
        let secs = u.int_in_range(-86_399..=86_399)?;
        let fixed_offset = FixedOffset::east_opt(secs)
            .expect("Could not generate a valid chrono::FixedOffset. It looks like implementation of Arbitrary for FixedOffset is erroneous.");
        Ok(fixed_offset)
    }
}

#[cfg(test)]
mod tests {
    use super::FixedOffset;
    use crate::offset::TimeZone;
    use std::str::FromStr;

    #[test]
    fn test_date_extreme_offset() {
        // starting from 0.3 we don't have an offset exceeding one day.
        // this makes everything easier!
        let offset = FixedOffset::east_opt(86399).unwrap();
        assert_eq!(
            format!("{:?}", offset.with_ymd_and_hms(2012, 2, 29, 5, 6, 7).unwrap()),
            "2012-02-29T05:06:07+23:59:59"
        );
        let offset = FixedOffset::east_opt(-86399).unwrap();
        assert_eq!(
            format!("{:?}", offset.with_ymd_and_hms(2012, 2, 29, 5, 6, 7).unwrap()),
            "2012-02-29T05:06:07-23:59:59"
        );
        let offset = FixedOffset::west_opt(86399).unwrap();
        assert_eq!(
            format!("{:?}", offset.with_ymd_and_hms(2012, 3, 4, 5, 6, 7).unwrap()),
            "2012-03-04T05:06:07-23:59:59"
        );
        let offset = FixedOffset::west_opt(-86399).unwrap();
        assert_eq!(
            format!("{:?}", offset.with_ymd_and_hms(2012, 3, 4, 5, 6, 7).unwrap()),
            "2012-03-04T05:06:07+23:59:59"
        );
    }

    #[test]
    fn test_parse_offset() {
        let offset = FixedOffset::from_str("-0500").unwrap();
        assert_eq!(offset.local_minus_utc, -5 * 3600);
        let offset = FixedOffset::from_str("-08:00").unwrap();
        assert_eq!(offset.local_minus_utc, -8 * 3600);
        let offset = FixedOffset::from_str("+06:30").unwrap();
        assert_eq!(offset.local_minus_utc, (6 * 3600) + 1800);
    }

    #[test]
    #[cfg(feature = "rkyv-validation")]
    fn test_rkyv_validation() {
        let offset = FixedOffset::from_str("-0500").unwrap();
        let bytes = rkyv::to_bytes::<_, 4>(&offset).unwrap();
        assert_eq!(rkyv::from_bytes::<FixedOffset>(&bytes).unwrap(), offset);
    }
}