chrono/format/
formatting.rs

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1// This is a part of Chrono.
2// See README.md and LICENSE.txt for details.
3
4//! Date and time formatting routines.
5
6#[cfg(all(feature = "alloc", not(feature = "std"), not(test)))]
7use alloc::string::{String, ToString};
8#[cfg(feature = "alloc")]
9use core::borrow::Borrow;
10#[cfg(feature = "alloc")]
11use core::fmt::Display;
12use core::fmt::{self, Write};
13
14#[cfg(feature = "alloc")]
15use crate::offset::Offset;
16#[cfg(any(feature = "alloc", feature = "serde"))]
17use crate::{Datelike, FixedOffset, NaiveDateTime, Timelike};
18#[cfg(feature = "alloc")]
19use crate::{NaiveDate, NaiveTime, Weekday};
20
21#[cfg(feature = "alloc")]
22use super::locales;
23#[cfg(any(feature = "alloc", feature = "serde"))]
24use super::{Colons, OffsetFormat, OffsetPrecision, Pad};
25#[cfg(feature = "alloc")]
26use super::{Fixed, InternalFixed, InternalInternal, Item, Numeric};
27#[cfg(feature = "alloc")]
28use locales::*;
29
30/// A *temporary* object which can be used as an argument to `format!` or others.
31/// This is normally constructed via `format` methods of each date and time type.
32#[cfg(feature = "alloc")]
33#[derive(Debug)]
34pub struct DelayedFormat<I> {
35    /// The date view, if any.
36    date: Option<NaiveDate>,
37    /// The time view, if any.
38    time: Option<NaiveTime>,
39    /// The name and local-to-UTC difference for the offset (timezone), if any.
40    off: Option<(String, FixedOffset)>,
41    /// An iterator returning formatting items.
42    items: I,
43    /// Locale used for text.
44    /// ZST if the `unstable-locales` feature is not enabled.
45    locale: Locale,
46}
47
48#[cfg(feature = "alloc")]
49impl<'a, I: Iterator<Item = B> + Clone, B: Borrow<Item<'a>>> DelayedFormat<I> {
50    /// Makes a new `DelayedFormat` value out of local date and time.
51    #[must_use]
52    pub fn new(date: Option<NaiveDate>, time: Option<NaiveTime>, items: I) -> DelayedFormat<I> {
53        DelayedFormat { date, time, off: None, items, locale: default_locale() }
54    }
55
56    /// Makes a new `DelayedFormat` value out of local date and time and UTC offset.
57    #[must_use]
58    pub fn new_with_offset<Off>(
59        date: Option<NaiveDate>,
60        time: Option<NaiveTime>,
61        offset: &Off,
62        items: I,
63    ) -> DelayedFormat<I>
64    where
65        Off: Offset + Display,
66    {
67        let name_and_diff = (offset.to_string(), offset.fix());
68        DelayedFormat { date, time, off: Some(name_and_diff), items, locale: default_locale() }
69    }
70
71    /// Makes a new `DelayedFormat` value out of local date and time and locale.
72    #[cfg(feature = "unstable-locales")]
73    #[must_use]
74    pub fn new_with_locale(
75        date: Option<NaiveDate>,
76        time: Option<NaiveTime>,
77        items: I,
78        locale: Locale,
79    ) -> DelayedFormat<I> {
80        DelayedFormat { date, time, off: None, items, locale }
81    }
82
83    /// Makes a new `DelayedFormat` value out of local date and time, UTC offset and locale.
84    #[cfg(feature = "unstable-locales")]
85    #[must_use]
86    pub fn new_with_offset_and_locale<Off>(
87        date: Option<NaiveDate>,
88        time: Option<NaiveTime>,
89        offset: &Off,
90        items: I,
91        locale: Locale,
92    ) -> DelayedFormat<I>
93    where
94        Off: Offset + Display,
95    {
96        let name_and_diff = (offset.to_string(), offset.fix());
97        DelayedFormat { date, time, off: Some(name_and_diff), items, locale }
98    }
99
100    /// Formats `DelayedFormat` into a `core::fmt::Write` instance.
101    /// # Errors
102    /// This function returns a `core::fmt::Error` if formatting into the `core::fmt::Write` instance fails.
103    ///
104    /// # Example
105    /// ### Writing to a String
106    /// ```
107    /// let dt = chrono::DateTime::from_timestamp(1643723400, 123456789).unwrap();
108    /// let df = dt.format("%Y-%m-%d %H:%M:%S%.9f");
109    /// let mut buffer = String::new();
110    /// let _ = df.write_to(&mut buffer);
111    /// ```
112    pub fn write_to(&self, w: &mut impl Write) -> fmt::Result {
113        for item in self.items.clone() {
114            match *item.borrow() {
115                Item::Literal(s) | Item::Space(s) => w.write_str(s),
116                #[cfg(feature = "alloc")]
117                Item::OwnedLiteral(ref s) | Item::OwnedSpace(ref s) => w.write_str(s),
118                Item::Numeric(ref spec, pad) => self.format_numeric(w, spec, pad),
119                Item::Fixed(ref spec) => self.format_fixed(w, spec),
120                Item::Error => Err(fmt::Error),
121            }?;
122        }
123        Ok(())
124    }
125
126    #[cfg(feature = "alloc")]
127    fn format_numeric(&self, w: &mut impl Write, spec: &Numeric, pad: Pad) -> fmt::Result {
128        use self::Numeric::*;
129
130        fn write_one(w: &mut impl Write, v: u8) -> fmt::Result {
131            w.write_char((b'0' + v) as char)
132        }
133
134        fn write_two(w: &mut impl Write, v: u8, pad: Pad) -> fmt::Result {
135            let ones = b'0' + v % 10;
136            match (v / 10, pad) {
137                (0, Pad::None) => {}
138                (0, Pad::Space) => w.write_char(' ')?,
139                (tens, _) => w.write_char((b'0' + tens) as char)?,
140            }
141            w.write_char(ones as char)
142        }
143
144        #[inline]
145        fn write_year(w: &mut impl Write, year: i32, pad: Pad) -> fmt::Result {
146            if (1000..=9999).contains(&year) {
147                // fast path
148                write_hundreds(w, (year / 100) as u8)?;
149                write_hundreds(w, (year % 100) as u8)
150            } else {
151                write_n(w, 4, year as i64, pad, !(0..10_000).contains(&year))
152            }
153        }
154
155        fn write_n(
156            w: &mut impl Write,
157            n: usize,
158            v: i64,
159            pad: Pad,
160            always_sign: bool,
161        ) -> fmt::Result {
162            if always_sign {
163                match pad {
164                    Pad::None => write!(w, "{:+}", v),
165                    Pad::Zero => write!(w, "{:+01$}", v, n + 1),
166                    Pad::Space => write!(w, "{:+1$}", v, n + 1),
167                }
168            } else {
169                match pad {
170                    Pad::None => write!(w, "{}", v),
171                    Pad::Zero => write!(w, "{:01$}", v, n),
172                    Pad::Space => write!(w, "{:1$}", v, n),
173                }
174            }
175        }
176
177        match (spec, self.date, self.time) {
178            (Year, Some(d), _) => write_year(w, d.year(), pad),
179            (YearDiv100, Some(d), _) => write_two(w, d.year().div_euclid(100) as u8, pad),
180            (YearMod100, Some(d), _) => write_two(w, d.year().rem_euclid(100) as u8, pad),
181            (IsoYear, Some(d), _) => write_year(w, d.iso_week().year(), pad),
182            (IsoYearDiv100, Some(d), _) => {
183                write_two(w, d.iso_week().year().div_euclid(100) as u8, pad)
184            }
185            (IsoYearMod100, Some(d), _) => {
186                write_two(w, d.iso_week().year().rem_euclid(100) as u8, pad)
187            }
188            (Quarter, Some(d), _) => write_one(w, d.quarter() as u8),
189            (Month, Some(d), _) => write_two(w, d.month() as u8, pad),
190            (Day, Some(d), _) => write_two(w, d.day() as u8, pad),
191            (WeekFromSun, Some(d), _) => write_two(w, d.weeks_from(Weekday::Sun) as u8, pad),
192            (WeekFromMon, Some(d), _) => write_two(w, d.weeks_from(Weekday::Mon) as u8, pad),
193            (IsoWeek, Some(d), _) => write_two(w, d.iso_week().week() as u8, pad),
194            (NumDaysFromSun, Some(d), _) => write_one(w, d.weekday().num_days_from_sunday() as u8),
195            (WeekdayFromMon, Some(d), _) => write_one(w, d.weekday().number_from_monday() as u8),
196            (Ordinal, Some(d), _) => write_n(w, 3, d.ordinal() as i64, pad, false),
197            (Hour, _, Some(t)) => write_two(w, t.hour() as u8, pad),
198            (Hour12, _, Some(t)) => write_two(w, t.hour12().1 as u8, pad),
199            (Minute, _, Some(t)) => write_two(w, t.minute() as u8, pad),
200            (Second, _, Some(t)) => {
201                write_two(w, (t.second() + t.nanosecond() / 1_000_000_000) as u8, pad)
202            }
203            (Nanosecond, _, Some(t)) => {
204                write_n(w, 9, (t.nanosecond() % 1_000_000_000) as i64, pad, false)
205            }
206            (Timestamp, Some(d), Some(t)) => {
207                let offset = self.off.as_ref().map(|(_, o)| i64::from(o.local_minus_utc()));
208                let timestamp = d.and_time(t).and_utc().timestamp() - offset.unwrap_or(0);
209                write_n(w, 9, timestamp, pad, false)
210            }
211            (Internal(_), _, _) => Ok(()), // for future expansion
212            _ => Err(fmt::Error),          // insufficient arguments for given format
213        }
214    }
215
216    #[cfg(feature = "alloc")]
217    fn format_fixed(&self, w: &mut impl Write, spec: &Fixed) -> fmt::Result {
218        use Fixed::*;
219        use InternalInternal::*;
220
221        match (spec, self.date, self.time, self.off.as_ref()) {
222            (ShortMonthName, Some(d), _, _) => {
223                w.write_str(short_months(self.locale)[d.month0() as usize])
224            }
225            (LongMonthName, Some(d), _, _) => {
226                w.write_str(long_months(self.locale)[d.month0() as usize])
227            }
228            (ShortWeekdayName, Some(d), _, _) => w.write_str(
229                short_weekdays(self.locale)[d.weekday().num_days_from_sunday() as usize],
230            ),
231            (LongWeekdayName, Some(d), _, _) => {
232                w.write_str(long_weekdays(self.locale)[d.weekday().num_days_from_sunday() as usize])
233            }
234            (LowerAmPm, _, Some(t), _) => {
235                let ampm = if t.hour12().0 { am_pm(self.locale)[1] } else { am_pm(self.locale)[0] };
236                for c in ampm.chars().flat_map(|c| c.to_lowercase()) {
237                    w.write_char(c)?
238                }
239                Ok(())
240            }
241            (UpperAmPm, _, Some(t), _) => {
242                let ampm = if t.hour12().0 { am_pm(self.locale)[1] } else { am_pm(self.locale)[0] };
243                w.write_str(ampm)
244            }
245            (Nanosecond, _, Some(t), _) => {
246                let nano = t.nanosecond() % 1_000_000_000;
247                if nano == 0 {
248                    Ok(())
249                } else {
250                    w.write_str(decimal_point(self.locale))?;
251                    if nano % 1_000_000 == 0 {
252                        write!(w, "{:03}", nano / 1_000_000)
253                    } else if nano % 1_000 == 0 {
254                        write!(w, "{:06}", nano / 1_000)
255                    } else {
256                        write!(w, "{:09}", nano)
257                    }
258                }
259            }
260            (Nanosecond3, _, Some(t), _) => {
261                w.write_str(decimal_point(self.locale))?;
262                write!(w, "{:03}", t.nanosecond() / 1_000_000 % 1000)
263            }
264            (Nanosecond6, _, Some(t), _) => {
265                w.write_str(decimal_point(self.locale))?;
266                write!(w, "{:06}", t.nanosecond() / 1_000 % 1_000_000)
267            }
268            (Nanosecond9, _, Some(t), _) => {
269                w.write_str(decimal_point(self.locale))?;
270                write!(w, "{:09}", t.nanosecond() % 1_000_000_000)
271            }
272            (Internal(InternalFixed { val: Nanosecond3NoDot }), _, Some(t), _) => {
273                write!(w, "{:03}", t.nanosecond() / 1_000_000 % 1_000)
274            }
275            (Internal(InternalFixed { val: Nanosecond6NoDot }), _, Some(t), _) => {
276                write!(w, "{:06}", t.nanosecond() / 1_000 % 1_000_000)
277            }
278            (Internal(InternalFixed { val: Nanosecond9NoDot }), _, Some(t), _) => {
279                write!(w, "{:09}", t.nanosecond() % 1_000_000_000)
280            }
281            (TimezoneName, _, _, Some((tz_name, _))) => write!(w, "{}", tz_name),
282            (TimezoneOffset | TimezoneOffsetZ, _, _, Some((_, off))) => {
283                let offset_format = OffsetFormat {
284                    precision: OffsetPrecision::Minutes,
285                    colons: Colons::Maybe,
286                    allow_zulu: *spec == TimezoneOffsetZ,
287                    padding: Pad::Zero,
288                };
289                offset_format.format(w, *off)
290            }
291            (TimezoneOffsetColon | TimezoneOffsetColonZ, _, _, Some((_, off))) => {
292                let offset_format = OffsetFormat {
293                    precision: OffsetPrecision::Minutes,
294                    colons: Colons::Colon,
295                    allow_zulu: *spec == TimezoneOffsetColonZ,
296                    padding: Pad::Zero,
297                };
298                offset_format.format(w, *off)
299            }
300            (TimezoneOffsetDoubleColon, _, _, Some((_, off))) => {
301                let offset_format = OffsetFormat {
302                    precision: OffsetPrecision::Seconds,
303                    colons: Colons::Colon,
304                    allow_zulu: false,
305                    padding: Pad::Zero,
306                };
307                offset_format.format(w, *off)
308            }
309            (TimezoneOffsetTripleColon, _, _, Some((_, off))) => {
310                let offset_format = OffsetFormat {
311                    precision: OffsetPrecision::Hours,
312                    colons: Colons::None,
313                    allow_zulu: false,
314                    padding: Pad::Zero,
315                };
316                offset_format.format(w, *off)
317            }
318            (RFC2822, Some(d), Some(t), Some((_, off))) => {
319                write_rfc2822(w, crate::NaiveDateTime::new(d, t), *off)
320            }
321            (RFC3339, Some(d), Some(t), Some((_, off))) => write_rfc3339(
322                w,
323                crate::NaiveDateTime::new(d, t),
324                *off,
325                SecondsFormat::AutoSi,
326                false,
327            ),
328            _ => Err(fmt::Error), // insufficient arguments for given format
329        }
330    }
331}
332
333#[cfg(feature = "alloc")]
334impl<'a, I: Iterator<Item = B> + Clone, B: Borrow<Item<'a>>> Display for DelayedFormat<I> {
335    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
336        let mut result = String::new();
337        self.write_to(&mut result)?;
338        f.pad(&result)
339    }
340}
341
342/// Tries to format given arguments with given formatting items.
343/// Internally used by `DelayedFormat`.
344#[cfg(feature = "alloc")]
345#[deprecated(since = "0.4.32", note = "Use DelayedFormat::fmt or DelayedFormat::write_to instead")]
346pub fn format<'a, I, B>(
347    w: &mut fmt::Formatter,
348    date: Option<&NaiveDate>,
349    time: Option<&NaiveTime>,
350    off: Option<&(String, FixedOffset)>,
351    items: I,
352) -> fmt::Result
353where
354    I: Iterator<Item = B> + Clone,
355    B: Borrow<Item<'a>>,
356{
357    DelayedFormat {
358        date: date.copied(),
359        time: time.copied(),
360        off: off.cloned(),
361        items,
362        locale: default_locale(),
363    }
364    .fmt(w)
365}
366
367/// Formats single formatting item
368#[cfg(feature = "alloc")]
369#[deprecated(since = "0.4.32", note = "Use DelayedFormat::fmt or DelayedFormat::write_to instead")]
370pub fn format_item(
371    w: &mut fmt::Formatter,
372    date: Option<&NaiveDate>,
373    time: Option<&NaiveTime>,
374    off: Option<&(String, FixedOffset)>,
375    item: &Item<'_>,
376) -> fmt::Result {
377    DelayedFormat {
378        date: date.copied(),
379        time: time.copied(),
380        off: off.cloned(),
381        items: [item].into_iter(),
382        locale: default_locale(),
383    }
384    .fmt(w)
385}
386
387#[cfg(any(feature = "alloc", feature = "serde"))]
388impl OffsetFormat {
389    /// Writes an offset from UTC with the format defined by `self`.
390    fn format(&self, w: &mut impl Write, off: FixedOffset) -> fmt::Result {
391        let off = off.local_minus_utc();
392        if self.allow_zulu && off == 0 {
393            w.write_char('Z')?;
394            return Ok(());
395        }
396        let (sign, off) = if off < 0 { ('-', -off) } else { ('+', off) };
397
398        let hours;
399        let mut mins = 0;
400        let mut secs = 0;
401        let precision = match self.precision {
402            OffsetPrecision::Hours => {
403                // Minutes and seconds are simply truncated
404                hours = (off / 3600) as u8;
405                OffsetPrecision::Hours
406            }
407            OffsetPrecision::Minutes | OffsetPrecision::OptionalMinutes => {
408                // Round seconds to the nearest minute.
409                let minutes = (off + 30) / 60;
410                mins = (minutes % 60) as u8;
411                hours = (minutes / 60) as u8;
412                if self.precision == OffsetPrecision::OptionalMinutes && mins == 0 {
413                    OffsetPrecision::Hours
414                } else {
415                    OffsetPrecision::Minutes
416                }
417            }
418            OffsetPrecision::Seconds
419            | OffsetPrecision::OptionalSeconds
420            | OffsetPrecision::OptionalMinutesAndSeconds => {
421                let minutes = off / 60;
422                secs = (off % 60) as u8;
423                mins = (minutes % 60) as u8;
424                hours = (minutes / 60) as u8;
425                if self.precision != OffsetPrecision::Seconds && secs == 0 {
426                    if self.precision == OffsetPrecision::OptionalMinutesAndSeconds && mins == 0 {
427                        OffsetPrecision::Hours
428                    } else {
429                        OffsetPrecision::Minutes
430                    }
431                } else {
432                    OffsetPrecision::Seconds
433                }
434            }
435        };
436        let colons = self.colons == Colons::Colon;
437
438        if hours < 10 {
439            if self.padding == Pad::Space {
440                w.write_char(' ')?;
441            }
442            w.write_char(sign)?;
443            if self.padding == Pad::Zero {
444                w.write_char('0')?;
445            }
446            w.write_char((b'0' + hours) as char)?;
447        } else {
448            w.write_char(sign)?;
449            write_hundreds(w, hours)?;
450        }
451        if let OffsetPrecision::Minutes | OffsetPrecision::Seconds = precision {
452            if colons {
453                w.write_char(':')?;
454            }
455            write_hundreds(w, mins)?;
456        }
457        if let OffsetPrecision::Seconds = precision {
458            if colons {
459                w.write_char(':')?;
460            }
461            write_hundreds(w, secs)?;
462        }
463        Ok(())
464    }
465}
466
467/// Specific formatting options for seconds. This may be extended in the
468/// future, so exhaustive matching in external code is not recommended.
469///
470/// See the `TimeZone::to_rfc3339_opts` function for usage.
471#[derive(Clone, Copy, Debug, Eq, PartialEq, Hash)]
472#[allow(clippy::manual_non_exhaustive)]
473pub enum SecondsFormat {
474    /// Format whole seconds only, with no decimal point nor subseconds.
475    Secs,
476
477    /// Use fixed 3 subsecond digits. This corresponds to [Fixed::Nanosecond3].
478    Millis,
479
480    /// Use fixed 6 subsecond digits. This corresponds to [Fixed::Nanosecond6].
481    Micros,
482
483    /// Use fixed 9 subsecond digits. This corresponds to [Fixed::Nanosecond9].
484    Nanos,
485
486    /// Automatically select one of `Secs`, `Millis`, `Micros`, or `Nanos` to display all available
487    /// non-zero sub-second digits.  This corresponds to [Fixed::Nanosecond].
488    AutoSi,
489
490    // Do not match against this.
491    #[doc(hidden)]
492    __NonExhaustive,
493}
494
495/// Writes the date, time and offset to the string. same as `%Y-%m-%dT%H:%M:%S%.f%:z`
496#[inline]
497#[cfg(any(feature = "alloc", feature = "serde"))]
498pub(crate) fn write_rfc3339(
499    w: &mut impl Write,
500    dt: NaiveDateTime,
501    off: FixedOffset,
502    secform: SecondsFormat,
503    use_z: bool,
504) -> fmt::Result {
505    let year = dt.date().year();
506    if (0..=9999).contains(&year) {
507        write_hundreds(w, (year / 100) as u8)?;
508        write_hundreds(w, (year % 100) as u8)?;
509    } else {
510        // ISO 8601 requires the explicit sign for out-of-range years
511        write!(w, "{:+05}", year)?;
512    }
513    w.write_char('-')?;
514    write_hundreds(w, dt.date().month() as u8)?;
515    w.write_char('-')?;
516    write_hundreds(w, dt.date().day() as u8)?;
517
518    w.write_char('T')?;
519
520    let (hour, min, mut sec) = dt.time().hms();
521    let mut nano = dt.nanosecond();
522    if nano >= 1_000_000_000 {
523        sec += 1;
524        nano -= 1_000_000_000;
525    }
526    write_hundreds(w, hour as u8)?;
527    w.write_char(':')?;
528    write_hundreds(w, min as u8)?;
529    w.write_char(':')?;
530    let sec = sec;
531    write_hundreds(w, sec as u8)?;
532
533    match secform {
534        SecondsFormat::Secs => {}
535        SecondsFormat::Millis => write!(w, ".{:03}", nano / 1_000_000)?,
536        SecondsFormat::Micros => write!(w, ".{:06}", nano / 1000)?,
537        SecondsFormat::Nanos => write!(w, ".{:09}", nano)?,
538        SecondsFormat::AutoSi => {
539            if nano == 0 {
540            } else if nano % 1_000_000 == 0 {
541                write!(w, ".{:03}", nano / 1_000_000)?
542            } else if nano % 1_000 == 0 {
543                write!(w, ".{:06}", nano / 1_000)?
544            } else {
545                write!(w, ".{:09}", nano)?
546            }
547        }
548        SecondsFormat::__NonExhaustive => unreachable!(),
549    };
550
551    OffsetFormat {
552        precision: OffsetPrecision::Minutes,
553        colons: Colons::Colon,
554        allow_zulu: use_z,
555        padding: Pad::Zero,
556    }
557    .format(w, off)
558}
559
560#[cfg(feature = "alloc")]
561/// write datetimes like `Tue, 1 Jul 2003 10:52:37 +0200`, same as `%a, %d %b %Y %H:%M:%S %z`
562pub(crate) fn write_rfc2822(
563    w: &mut impl Write,
564    dt: NaiveDateTime,
565    off: FixedOffset,
566) -> fmt::Result {
567    let year = dt.year();
568    // RFC2822 is only defined on years 0 through 9999
569    if !(0..=9999).contains(&year) {
570        return Err(fmt::Error);
571    }
572
573    let english = default_locale();
574
575    w.write_str(short_weekdays(english)[dt.weekday().num_days_from_sunday() as usize])?;
576    w.write_str(", ")?;
577    let day = dt.day();
578    if day < 10 {
579        w.write_char((b'0' + day as u8) as char)?;
580    } else {
581        write_hundreds(w, day as u8)?;
582    }
583    w.write_char(' ')?;
584    w.write_str(short_months(english)[dt.month0() as usize])?;
585    w.write_char(' ')?;
586    write_hundreds(w, (year / 100) as u8)?;
587    write_hundreds(w, (year % 100) as u8)?;
588    w.write_char(' ')?;
589
590    let (hour, min, sec) = dt.time().hms();
591    write_hundreds(w, hour as u8)?;
592    w.write_char(':')?;
593    write_hundreds(w, min as u8)?;
594    w.write_char(':')?;
595    let sec = sec + dt.nanosecond() / 1_000_000_000;
596    write_hundreds(w, sec as u8)?;
597    w.write_char(' ')?;
598    OffsetFormat {
599        precision: OffsetPrecision::Minutes,
600        colons: Colons::None,
601        allow_zulu: false,
602        padding: Pad::Zero,
603    }
604    .format(w, off)
605}
606
607/// Equivalent to `{:02}` formatting for n < 100.
608pub(crate) fn write_hundreds(w: &mut impl Write, n: u8) -> fmt::Result {
609    if n >= 100 {
610        return Err(fmt::Error);
611    }
612
613    let tens = b'0' + n / 10;
614    let ones = b'0' + n % 10;
615    w.write_char(tens as char)?;
616    w.write_char(ones as char)
617}
618
619#[cfg(test)]
620#[cfg(feature = "alloc")]
621mod tests {
622    use super::{Colons, OffsetFormat, OffsetPrecision, Pad};
623    use crate::FixedOffset;
624    #[cfg(feature = "alloc")]
625    use crate::{NaiveDate, NaiveTime, TimeZone, Timelike, Utc};
626
627    #[cfg(feature = "alloc")]
628    #[test]
629    fn test_delayed_write_to() {
630        let dt = crate::DateTime::from_timestamp(1643723400, 123456789).unwrap();
631        let df = dt.format("%Y-%m-%d %H:%M:%S%.9f");
632
633        let mut dt_str = String::new();
634
635        df.write_to(&mut dt_str).unwrap();
636        assert_eq!(dt_str, "2022-02-01 13:50:00.123456789");
637    }
638
639    #[cfg(all(feature = "std", feature = "unstable-locales", feature = "alloc"))]
640    #[test]
641    fn test_with_locale_delayed_write_to() {
642        use crate::DateTime;
643        use crate::format::locales::Locale;
644
645        let dt = DateTime::from_timestamp(1643723400, 123456789).unwrap();
646        let df = dt.format_localized("%A, %B %d, %Y", Locale::ja_JP);
647
648        let mut dt_str = String::new();
649
650        df.write_to(&mut dt_str).unwrap();
651
652        assert_eq!(dt_str, "火曜日, 2月 01, 2022");
653    }
654
655    #[test]
656    #[cfg(feature = "alloc")]
657    fn test_date_format() {
658        let d = NaiveDate::from_ymd_opt(2012, 3, 4).unwrap();
659        assert_eq!(d.format("%Y,%C,%y,%G,%g").to_string(), "2012,20,12,2012,12");
660        assert_eq!(d.format("%m,%b,%h,%B").to_string(), "03,Mar,Mar,March");
661        assert_eq!(d.format("%q").to_string(), "1");
662        assert_eq!(d.format("%d,%e").to_string(), "04, 4");
663        assert_eq!(d.format("%U,%W,%V").to_string(), "10,09,09");
664        assert_eq!(d.format("%a,%A,%w,%u").to_string(), "Sun,Sunday,0,7");
665        assert_eq!(d.format("%j").to_string(), "064"); // since 2012 is a leap year
666        assert_eq!(d.format("%D,%x").to_string(), "03/04/12,03/04/12");
667        assert_eq!(d.format("%F").to_string(), "2012-03-04");
668        assert_eq!(d.format("%v").to_string(), " 4-Mar-2012");
669        assert_eq!(d.format("%t%n%%%n%t").to_string(), "\t\n%\n\t");
670
671        // non-four-digit years
672        assert_eq!(
673            NaiveDate::from_ymd_opt(12345, 1, 1).unwrap().format("%Y").to_string(),
674            "+12345"
675        );
676        assert_eq!(NaiveDate::from_ymd_opt(1234, 1, 1).unwrap().format("%Y").to_string(), "1234");
677        assert_eq!(NaiveDate::from_ymd_opt(123, 1, 1).unwrap().format("%Y").to_string(), "0123");
678        assert_eq!(NaiveDate::from_ymd_opt(12, 1, 1).unwrap().format("%Y").to_string(), "0012");
679        assert_eq!(NaiveDate::from_ymd_opt(1, 1, 1).unwrap().format("%Y").to_string(), "0001");
680        assert_eq!(NaiveDate::from_ymd_opt(0, 1, 1).unwrap().format("%Y").to_string(), "0000");
681        assert_eq!(NaiveDate::from_ymd_opt(-1, 1, 1).unwrap().format("%Y").to_string(), "-0001");
682        assert_eq!(NaiveDate::from_ymd_opt(-12, 1, 1).unwrap().format("%Y").to_string(), "-0012");
683        assert_eq!(NaiveDate::from_ymd_opt(-123, 1, 1).unwrap().format("%Y").to_string(), "-0123");
684        assert_eq!(NaiveDate::from_ymd_opt(-1234, 1, 1).unwrap().format("%Y").to_string(), "-1234");
685        assert_eq!(
686            NaiveDate::from_ymd_opt(-12345, 1, 1).unwrap().format("%Y").to_string(),
687            "-12345"
688        );
689
690        // corner cases
691        assert_eq!(
692            NaiveDate::from_ymd_opt(2007, 12, 31).unwrap().format("%G,%g,%U,%W,%V").to_string(),
693            "2008,08,52,53,01"
694        );
695        assert_eq!(
696            NaiveDate::from_ymd_opt(2010, 1, 3).unwrap().format("%G,%g,%U,%W,%V").to_string(),
697            "2009,09,01,00,53"
698        );
699    }
700
701    #[test]
702    #[cfg(feature = "alloc")]
703    fn test_time_format() {
704        let t = NaiveTime::from_hms_nano_opt(3, 5, 7, 98765432).unwrap();
705        assert_eq!(t.format("%H,%k,%I,%l,%P,%p").to_string(), "03, 3,03, 3,am,AM");
706        assert_eq!(t.format("%M").to_string(), "05");
707        assert_eq!(t.format("%S,%f,%.f").to_string(), "07,098765432,.098765432");
708        assert_eq!(t.format("%.3f,%.6f,%.9f").to_string(), ".098,.098765,.098765432");
709        assert_eq!(t.format("%R").to_string(), "03:05");
710        assert_eq!(t.format("%T,%X").to_string(), "03:05:07,03:05:07");
711        assert_eq!(t.format("%r").to_string(), "03:05:07 AM");
712        assert_eq!(t.format("%t%n%%%n%t").to_string(), "\t\n%\n\t");
713
714        let t = NaiveTime::from_hms_micro_opt(3, 5, 7, 432100).unwrap();
715        assert_eq!(t.format("%S,%f,%.f").to_string(), "07,432100000,.432100");
716        assert_eq!(t.format("%.3f,%.6f,%.9f").to_string(), ".432,.432100,.432100000");
717
718        let t = NaiveTime::from_hms_milli_opt(3, 5, 7, 210).unwrap();
719        assert_eq!(t.format("%S,%f,%.f").to_string(), "07,210000000,.210");
720        assert_eq!(t.format("%.3f,%.6f,%.9f").to_string(), ".210,.210000,.210000000");
721
722        let t = NaiveTime::from_hms_opt(3, 5, 7).unwrap();
723        assert_eq!(t.format("%S,%f,%.f").to_string(), "07,000000000,");
724        assert_eq!(t.format("%.3f,%.6f,%.9f").to_string(), ".000,.000000,.000000000");
725
726        // corner cases
727        assert_eq!(
728            NaiveTime::from_hms_opt(13, 57, 9).unwrap().format("%r").to_string(),
729            "01:57:09 PM"
730        );
731        assert_eq!(
732            NaiveTime::from_hms_milli_opt(23, 59, 59, 1_000).unwrap().format("%X").to_string(),
733            "23:59:60"
734        );
735    }
736
737    #[test]
738    #[cfg(feature = "alloc")]
739    fn test_datetime_format() {
740        let dt =
741            NaiveDate::from_ymd_opt(2010, 9, 8).unwrap().and_hms_milli_opt(7, 6, 54, 321).unwrap();
742        assert_eq!(dt.format("%c").to_string(), "Wed Sep  8 07:06:54 2010");
743        assert_eq!(dt.format("%s").to_string(), "1283929614");
744        assert_eq!(dt.format("%t%n%%%n%t").to_string(), "\t\n%\n\t");
745
746        // a horror of leap second: coming near to you.
747        let dt = NaiveDate::from_ymd_opt(2012, 6, 30)
748            .unwrap()
749            .and_hms_milli_opt(23, 59, 59, 1_000)
750            .unwrap();
751        assert_eq!(dt.format("%c").to_string(), "Sat Jun 30 23:59:60 2012");
752        assert_eq!(dt.format("%s").to_string(), "1341100799"); // not 1341100800, it's intentional.
753    }
754
755    #[test]
756    #[cfg(feature = "alloc")]
757    fn test_datetime_format_alignment() {
758        let datetime = Utc
759            .with_ymd_and_hms(2007, 1, 2, 12, 34, 56)
760            .unwrap()
761            .with_nanosecond(123456789)
762            .unwrap();
763
764        // Item::Literal, odd number of padding bytes.
765        let percent = datetime.format("%%");
766        assert_eq!("   %", format!("{:>4}", percent));
767        assert_eq!("%   ", format!("{:<4}", percent));
768        assert_eq!(" %  ", format!("{:^4}", percent));
769
770        // Item::Numeric, custom non-ASCII padding character
771        let year = datetime.format("%Y");
772        assert_eq!("——2007", format!("{:—>6}", year));
773        assert_eq!("2007——", format!("{:—<6}", year));
774        assert_eq!("—2007—", format!("{:—^6}", year));
775
776        // Item::Fixed
777        let tz = datetime.format("%Z");
778        assert_eq!("  UTC", format!("{:>5}", tz));
779        assert_eq!("UTC  ", format!("{:<5}", tz));
780        assert_eq!(" UTC ", format!("{:^5}", tz));
781
782        // [Item::Numeric, Item::Space, Item::Literal, Item::Space, Item::Numeric]
783        let ymd = datetime.format("%Y %B %d");
784        assert_eq!("  2007 January 02", format!("{:>17}", ymd));
785        assert_eq!("2007 January 02  ", format!("{:<17}", ymd));
786        assert_eq!(" 2007 January 02 ", format!("{:^17}", ymd));
787
788        // Truncated
789        let time = datetime.format("%T%.6f");
790        assert_eq!("12:34:56.1234", format!("{:.13}", time));
791    }
792
793    #[test]
794    fn test_offset_formatting() {
795        fn check_all(precision: OffsetPrecision, expected: [[&str; 7]; 12]) {
796            fn check(
797                precision: OffsetPrecision,
798                colons: Colons,
799                padding: Pad,
800                allow_zulu: bool,
801                offsets: [FixedOffset; 7],
802                expected: [&str; 7],
803            ) {
804                let offset_format = OffsetFormat { precision, colons, allow_zulu, padding };
805                for (offset, expected) in offsets.iter().zip(expected.iter()) {
806                    let mut output = String::new();
807                    offset_format.format(&mut output, *offset).unwrap();
808                    assert_eq!(&output, expected);
809                }
810            }
811            // +03:45, -03:30, +11:00, -11:00:22, +02:34:26, -12:34:30, +00:00
812            let offsets = [
813                FixedOffset::east_opt(13_500).unwrap(),
814                FixedOffset::east_opt(-12_600).unwrap(),
815                FixedOffset::east_opt(39_600).unwrap(),
816                FixedOffset::east_opt(-39_622).unwrap(),
817                FixedOffset::east_opt(9266).unwrap(),
818                FixedOffset::east_opt(-45270).unwrap(),
819                FixedOffset::east_opt(0).unwrap(),
820            ];
821            check(precision, Colons::Colon, Pad::Zero, false, offsets, expected[0]);
822            check(precision, Colons::Colon, Pad::Zero, true, offsets, expected[1]);
823            check(precision, Colons::Colon, Pad::Space, false, offsets, expected[2]);
824            check(precision, Colons::Colon, Pad::Space, true, offsets, expected[3]);
825            check(precision, Colons::Colon, Pad::None, false, offsets, expected[4]);
826            check(precision, Colons::Colon, Pad::None, true, offsets, expected[5]);
827            check(precision, Colons::None, Pad::Zero, false, offsets, expected[6]);
828            check(precision, Colons::None, Pad::Zero, true, offsets, expected[7]);
829            check(precision, Colons::None, Pad::Space, false, offsets, expected[8]);
830            check(precision, Colons::None, Pad::Space, true, offsets, expected[9]);
831            check(precision, Colons::None, Pad::None, false, offsets, expected[10]);
832            check(precision, Colons::None, Pad::None, true, offsets, expected[11]);
833            // `Colons::Maybe` should format the same as `Colons::None`
834            check(precision, Colons::Maybe, Pad::Zero, false, offsets, expected[6]);
835            check(precision, Colons::Maybe, Pad::Zero, true, offsets, expected[7]);
836            check(precision, Colons::Maybe, Pad::Space, false, offsets, expected[8]);
837            check(precision, Colons::Maybe, Pad::Space, true, offsets, expected[9]);
838            check(precision, Colons::Maybe, Pad::None, false, offsets, expected[10]);
839            check(precision, Colons::Maybe, Pad::None, true, offsets, expected[11]);
840        }
841        check_all(
842            OffsetPrecision::Hours,
843            [
844                ["+03", "-03", "+11", "-11", "+02", "-12", "+00"],
845                ["+03", "-03", "+11", "-11", "+02", "-12", "Z"],
846                [" +3", " -3", "+11", "-11", " +2", "-12", " +0"],
847                [" +3", " -3", "+11", "-11", " +2", "-12", "Z"],
848                ["+3", "-3", "+11", "-11", "+2", "-12", "+0"],
849                ["+3", "-3", "+11", "-11", "+2", "-12", "Z"],
850                ["+03", "-03", "+11", "-11", "+02", "-12", "+00"],
851                ["+03", "-03", "+11", "-11", "+02", "-12", "Z"],
852                [" +3", " -3", "+11", "-11", " +2", "-12", " +0"],
853                [" +3", " -3", "+11", "-11", " +2", "-12", "Z"],
854                ["+3", "-3", "+11", "-11", "+2", "-12", "+0"],
855                ["+3", "-3", "+11", "-11", "+2", "-12", "Z"],
856            ],
857        );
858        check_all(
859            OffsetPrecision::Minutes,
860            [
861                ["+03:45", "-03:30", "+11:00", "-11:00", "+02:34", "-12:35", "+00:00"],
862                ["+03:45", "-03:30", "+11:00", "-11:00", "+02:34", "-12:35", "Z"],
863                [" +3:45", " -3:30", "+11:00", "-11:00", " +2:34", "-12:35", " +0:00"],
864                [" +3:45", " -3:30", "+11:00", "-11:00", " +2:34", "-12:35", "Z"],
865                ["+3:45", "-3:30", "+11:00", "-11:00", "+2:34", "-12:35", "+0:00"],
866                ["+3:45", "-3:30", "+11:00", "-11:00", "+2:34", "-12:35", "Z"],
867                ["+0345", "-0330", "+1100", "-1100", "+0234", "-1235", "+0000"],
868                ["+0345", "-0330", "+1100", "-1100", "+0234", "-1235", "Z"],
869                [" +345", " -330", "+1100", "-1100", " +234", "-1235", " +000"],
870                [" +345", " -330", "+1100", "-1100", " +234", "-1235", "Z"],
871                ["+345", "-330", "+1100", "-1100", "+234", "-1235", "+000"],
872                ["+345", "-330", "+1100", "-1100", "+234", "-1235", "Z"],
873            ],
874        );
875        #[rustfmt::skip]
876        check_all(
877            OffsetPrecision::Seconds,
878            [
879                ["+03:45:00", "-03:30:00", "+11:00:00", "-11:00:22", "+02:34:26", "-12:34:30", "+00:00:00"],
880                ["+03:45:00", "-03:30:00", "+11:00:00", "-11:00:22", "+02:34:26", "-12:34:30", "Z"],
881                [" +3:45:00", " -3:30:00", "+11:00:00", "-11:00:22", " +2:34:26", "-12:34:30", " +0:00:00"],
882                [" +3:45:00", " -3:30:00", "+11:00:00", "-11:00:22", " +2:34:26", "-12:34:30", "Z"],
883                ["+3:45:00", "-3:30:00", "+11:00:00", "-11:00:22", "+2:34:26", "-12:34:30", "+0:00:00"],
884                ["+3:45:00", "-3:30:00", "+11:00:00", "-11:00:22", "+2:34:26", "-12:34:30", "Z"],
885                ["+034500", "-033000", "+110000", "-110022", "+023426", "-123430", "+000000"],
886                ["+034500", "-033000", "+110000", "-110022", "+023426", "-123430", "Z"],
887                [" +34500", " -33000", "+110000", "-110022", " +23426", "-123430", " +00000"],
888                [" +34500", " -33000", "+110000", "-110022", " +23426", "-123430", "Z"],
889                ["+34500", "-33000", "+110000", "-110022", "+23426", "-123430", "+00000"],
890                ["+34500", "-33000", "+110000", "-110022", "+23426", "-123430", "Z"],
891            ],
892        );
893        check_all(
894            OffsetPrecision::OptionalMinutes,
895            [
896                ["+03:45", "-03:30", "+11", "-11", "+02:34", "-12:35", "+00"],
897                ["+03:45", "-03:30", "+11", "-11", "+02:34", "-12:35", "Z"],
898                [" +3:45", " -3:30", "+11", "-11", " +2:34", "-12:35", " +0"],
899                [" +3:45", " -3:30", "+11", "-11", " +2:34", "-12:35", "Z"],
900                ["+3:45", "-3:30", "+11", "-11", "+2:34", "-12:35", "+0"],
901                ["+3:45", "-3:30", "+11", "-11", "+2:34", "-12:35", "Z"],
902                ["+0345", "-0330", "+11", "-11", "+0234", "-1235", "+00"],
903                ["+0345", "-0330", "+11", "-11", "+0234", "-1235", "Z"],
904                [" +345", " -330", "+11", "-11", " +234", "-1235", " +0"],
905                [" +345", " -330", "+11", "-11", " +234", "-1235", "Z"],
906                ["+345", "-330", "+11", "-11", "+234", "-1235", "+0"],
907                ["+345", "-330", "+11", "-11", "+234", "-1235", "Z"],
908            ],
909        );
910        check_all(
911            OffsetPrecision::OptionalSeconds,
912            [
913                ["+03:45", "-03:30", "+11:00", "-11:00:22", "+02:34:26", "-12:34:30", "+00:00"],
914                ["+03:45", "-03:30", "+11:00", "-11:00:22", "+02:34:26", "-12:34:30", "Z"],
915                [" +3:45", " -3:30", "+11:00", "-11:00:22", " +2:34:26", "-12:34:30", " +0:00"],
916                [" +3:45", " -3:30", "+11:00", "-11:00:22", " +2:34:26", "-12:34:30", "Z"],
917                ["+3:45", "-3:30", "+11:00", "-11:00:22", "+2:34:26", "-12:34:30", "+0:00"],
918                ["+3:45", "-3:30", "+11:00", "-11:00:22", "+2:34:26", "-12:34:30", "Z"],
919                ["+0345", "-0330", "+1100", "-110022", "+023426", "-123430", "+0000"],
920                ["+0345", "-0330", "+1100", "-110022", "+023426", "-123430", "Z"],
921                [" +345", " -330", "+1100", "-110022", " +23426", "-123430", " +000"],
922                [" +345", " -330", "+1100", "-110022", " +23426", "-123430", "Z"],
923                ["+345", "-330", "+1100", "-110022", "+23426", "-123430", "+000"],
924                ["+345", "-330", "+1100", "-110022", "+23426", "-123430", "Z"],
925            ],
926        );
927        check_all(
928            OffsetPrecision::OptionalMinutesAndSeconds,
929            [
930                ["+03:45", "-03:30", "+11", "-11:00:22", "+02:34:26", "-12:34:30", "+00"],
931                ["+03:45", "-03:30", "+11", "-11:00:22", "+02:34:26", "-12:34:30", "Z"],
932                [" +3:45", " -3:30", "+11", "-11:00:22", " +2:34:26", "-12:34:30", " +0"],
933                [" +3:45", " -3:30", "+11", "-11:00:22", " +2:34:26", "-12:34:30", "Z"],
934                ["+3:45", "-3:30", "+11", "-11:00:22", "+2:34:26", "-12:34:30", "+0"],
935                ["+3:45", "-3:30", "+11", "-11:00:22", "+2:34:26", "-12:34:30", "Z"],
936                ["+0345", "-0330", "+11", "-110022", "+023426", "-123430", "+00"],
937                ["+0345", "-0330", "+11", "-110022", "+023426", "-123430", "Z"],
938                [" +345", " -330", "+11", "-110022", " +23426", "-123430", " +0"],
939                [" +345", " -330", "+11", "-110022", " +23426", "-123430", "Z"],
940                ["+345", "-330", "+11", "-110022", "+23426", "-123430", "+0"],
941                ["+345", "-330", "+11", "-110022", "+23426", "-123430", "Z"],
942            ],
943        );
944    }
945}
chrono/format/formatting.rs

chrono/format/
formatting.rs
