1 #![stable(feature = "duration_core", since = "1.25.0")]
3 //! Temporal quantification.
8 //! use std::time::Duration;
10 //! let five_seconds = Duration::new(5, 0);
11 //! // both declarations are equivalent
12 //! assert_eq!(Duration::new(5, 0), Duration::from_secs(5));
16 use crate::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
17 use crate::{fmt, u64};
19 const NANOS_PER_SEC: u32 = 1_000_000_000;
20 const NANOS_PER_MILLI: u32 = 1_000_000;
21 const NANOS_PER_MICRO: u32 = 1_000;
22 const MILLIS_PER_SEC: u64 = 1_000;
23 const MICROS_PER_SEC: u64 = 1_000_000;
25 /// A `Duration` type to represent a span of time, typically used for system
28 /// Each `Duration` is composed of a whole number of seconds and a fractional part
29 /// represented in nanoseconds. If the underlying system does not support
30 /// nanosecond-level precision, APIs binding a system timeout will typically round up
31 /// the number of nanoseconds.
33 /// `Duration`s implement many common traits, including [`Add`], [`Sub`], and other
36 /// [`Add`]: ../../std/ops/trait.Add.html
37 /// [`Sub`]: ../../std/ops/trait.Sub.html
38 /// [`ops`]: ../../std/ops/index.html
43 /// use std::time::Duration;
45 /// let five_seconds = Duration::new(5, 0);
46 /// let five_seconds_and_five_nanos = five_seconds + Duration::new(0, 5);
48 /// assert_eq!(five_seconds_and_five_nanos.as_secs(), 5);
49 /// assert_eq!(five_seconds_and_five_nanos.subsec_nanos(), 5);
51 /// let ten_millis = Duration::from_millis(10);
53 #[stable(feature = "duration", since = "1.3.0")]
54 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
57 nanos: u32, // Always 0 <= nanos < NANOS_PER_SEC
61 /// The duration of one second.
66 /// #![feature(duration_constants)]
67 /// use std::time::Duration;
69 /// assert_eq!(Duration::SECOND, Duration::from_secs(1));
71 #[unstable(feature = "duration_constants", issue = "57391")]
72 pub const SECOND: Duration = Duration::from_secs(1);
74 /// The duration of one millisecond.
79 /// #![feature(duration_constants)]
80 /// use std::time::Duration;
82 /// assert_eq!(Duration::MILLISECOND, Duration::from_millis(1));
84 #[unstable(feature = "duration_constants", issue = "57391")]
85 pub const MILLISECOND: Duration = Duration::from_millis(1);
87 /// The duration of one microsecond.
92 /// #![feature(duration_constants)]
93 /// use std::time::Duration;
95 /// assert_eq!(Duration::MICROSECOND, Duration::from_micros(1));
97 #[unstable(feature = "duration_constants", issue = "57391")]
98 pub const MICROSECOND: Duration = Duration::from_micros(1);
100 /// The duration of one nanosecond.
105 /// #![feature(duration_constants)]
106 /// use std::time::Duration;
108 /// assert_eq!(Duration::NANOSECOND, Duration::from_nanos(1));
110 #[unstable(feature = "duration_constants", issue = "57391")]
111 pub const NANOSECOND: Duration = Duration::from_nanos(1);
113 /// Creates a new `Duration` from the specified number of whole seconds and
114 /// additional nanoseconds.
116 /// If the number of nanoseconds is greater than 1 billion (the number of
117 /// nanoseconds in a second), then it will carry over into the seconds provided.
121 /// This constructor will panic if the carry from the nanoseconds overflows
122 /// the seconds counter.
127 /// use std::time::Duration;
129 /// let five_seconds = Duration::new(5, 0);
131 #[stable(feature = "duration", since = "1.3.0")]
133 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_consts", since = "1.32.0"))]
134 pub fn new(secs: u64, nanos: u32) -> Duration {
136 secs.checked_add((nanos / NANOS_PER_SEC) as u64).expect("overflow in Duration::new");
137 let nanos = nanos % NANOS_PER_SEC;
138 Duration { secs, nanos }
141 /// Creates a new `Duration` from the specified number of whole seconds.
146 /// use std::time::Duration;
148 /// let duration = Duration::from_secs(5);
150 /// assert_eq!(5, duration.as_secs());
151 /// assert_eq!(0, duration.subsec_nanos());
153 #[stable(feature = "duration", since = "1.3.0")]
156 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_consts", since = "1.32.0"))]
157 pub const fn from_secs(secs: u64) -> Duration {
158 Duration { secs, nanos: 0 }
161 /// Creates a new `Duration` from the specified number of milliseconds.
166 /// use std::time::Duration;
168 /// let duration = Duration::from_millis(2569);
170 /// assert_eq!(2, duration.as_secs());
171 /// assert_eq!(569_000_000, duration.subsec_nanos());
173 #[stable(feature = "duration", since = "1.3.0")]
176 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_consts", since = "1.32.0"))]
177 pub const fn from_millis(millis: u64) -> Duration {
179 secs: millis / MILLIS_PER_SEC,
180 nanos: ((millis % MILLIS_PER_SEC) as u32) * NANOS_PER_MILLI,
184 /// Creates a new `Duration` from the specified number of microseconds.
189 /// use std::time::Duration;
191 /// let duration = Duration::from_micros(1_000_002);
193 /// assert_eq!(1, duration.as_secs());
194 /// assert_eq!(2000, duration.subsec_nanos());
196 #[stable(feature = "duration_from_micros", since = "1.27.0")]
199 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_consts", since = "1.32.0"))]
200 pub const fn from_micros(micros: u64) -> Duration {
202 secs: micros / MICROS_PER_SEC,
203 nanos: ((micros % MICROS_PER_SEC) as u32) * NANOS_PER_MICRO,
207 /// Creates a new `Duration` from the specified number of nanoseconds.
212 /// use std::time::Duration;
214 /// let duration = Duration::from_nanos(1_000_000_123);
216 /// assert_eq!(1, duration.as_secs());
217 /// assert_eq!(123, duration.subsec_nanos());
219 #[stable(feature = "duration_extras", since = "1.27.0")]
222 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_consts", since = "1.32.0"))]
223 pub const fn from_nanos(nanos: u64) -> Duration {
225 secs: nanos / (NANOS_PER_SEC as u64),
226 nanos: (nanos % (NANOS_PER_SEC as u64)) as u32,
230 /// Returns the number of _whole_ seconds contained by this `Duration`.
232 /// The returned value does not include the fractional (nanosecond) part of the
233 /// duration, which can be obtained using [`subsec_nanos`].
238 /// use std::time::Duration;
240 /// let duration = Duration::new(5, 730023852);
241 /// assert_eq!(duration.as_secs(), 5);
244 /// To determine the total number of seconds represented by the `Duration`,
245 /// use `as_secs` in combination with [`subsec_nanos`]:
248 /// use std::time::Duration;
250 /// let duration = Duration::new(5, 730023852);
252 /// assert_eq!(5.730023852,
253 /// duration.as_secs() as f64
254 /// + duration.subsec_nanos() as f64 * 1e-9);
257 /// [`subsec_nanos`]: #method.subsec_nanos
258 #[stable(feature = "duration", since = "1.3.0")]
259 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration", since = "1.32.0"))]
261 pub const fn as_secs(&self) -> u64 {
265 /// Returns the fractional part of this `Duration`, in whole milliseconds.
267 /// This method does **not** return the length of the duration when
268 /// represented by milliseconds. The returned number always represents a
269 /// fractional portion of a second (i.e., it is less than one thousand).
274 /// use std::time::Duration;
276 /// let duration = Duration::from_millis(5432);
277 /// assert_eq!(duration.as_secs(), 5);
278 /// assert_eq!(duration.subsec_millis(), 432);
280 #[stable(feature = "duration_extras", since = "1.27.0")]
281 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_extras", since = "1.32.0"))]
283 pub const fn subsec_millis(&self) -> u32 {
284 self.nanos / NANOS_PER_MILLI
287 /// Returns the fractional part of this `Duration`, in whole microseconds.
289 /// This method does **not** return the length of the duration when
290 /// represented by microseconds. The returned number always represents a
291 /// fractional portion of a second (i.e., it is less than one million).
296 /// use std::time::Duration;
298 /// let duration = Duration::from_micros(1_234_567);
299 /// assert_eq!(duration.as_secs(), 1);
300 /// assert_eq!(duration.subsec_micros(), 234_567);
302 #[stable(feature = "duration_extras", since = "1.27.0")]
303 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_extras", since = "1.32.0"))]
305 pub const fn subsec_micros(&self) -> u32 {
306 self.nanos / NANOS_PER_MICRO
309 /// Returns the fractional part of this `Duration`, in nanoseconds.
311 /// This method does **not** return the length of the duration when
312 /// represented by nanoseconds. The returned number always represents a
313 /// fractional portion of a second (i.e., it is less than one billion).
318 /// use std::time::Duration;
320 /// let duration = Duration::from_millis(5010);
321 /// assert_eq!(duration.as_secs(), 5);
322 /// assert_eq!(duration.subsec_nanos(), 10_000_000);
324 #[stable(feature = "duration", since = "1.3.0")]
325 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration", since = "1.32.0"))]
327 pub const fn subsec_nanos(&self) -> u32 {
331 /// Returns the total number of whole milliseconds contained by this `Duration`.
336 /// use std::time::Duration;
338 /// let duration = Duration::new(5, 730023852);
339 /// assert_eq!(duration.as_millis(), 5730);
341 #[stable(feature = "duration_as_u128", since = "1.33.0")]
342 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_as_u128", since = "1.33.0"))]
344 pub const fn as_millis(&self) -> u128 {
345 self.secs as u128 * MILLIS_PER_SEC as u128 + (self.nanos / NANOS_PER_MILLI) as u128
348 /// Returns the total number of whole microseconds contained by this `Duration`.
353 /// use std::time::Duration;
355 /// let duration = Duration::new(5, 730023852);
356 /// assert_eq!(duration.as_micros(), 5730023);
358 #[stable(feature = "duration_as_u128", since = "1.33.0")]
359 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_as_u128", since = "1.33.0"))]
361 pub const fn as_micros(&self) -> u128 {
362 self.secs as u128 * MICROS_PER_SEC as u128 + (self.nanos / NANOS_PER_MICRO) as u128
365 /// Returns the total number of nanoseconds contained by this `Duration`.
370 /// use std::time::Duration;
372 /// let duration = Duration::new(5, 730023852);
373 /// assert_eq!(duration.as_nanos(), 5730023852);
375 #[stable(feature = "duration_as_u128", since = "1.33.0")]
376 #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "duration_as_u128", since = "1.33.0"))]
378 pub const fn as_nanos(&self) -> u128 {
379 self.secs as u128 * NANOS_PER_SEC as u128 + self.nanos as u128
382 /// Checked `Duration` addition. Computes `self + other`, returning [`None`]
383 /// if overflow occurred.
385 /// [`None`]: ../../std/option/enum.Option.html#variant.None
392 /// use std::time::Duration;
394 /// assert_eq!(Duration::new(0, 0).checked_add(Duration::new(0, 1)), Some(Duration::new(0, 1)));
395 /// assert_eq!(Duration::new(1, 0).checked_add(Duration::new(std::u64::MAX, 0)), None);
397 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
399 pub fn checked_add(self, rhs: Duration) -> Option<Duration> {
400 if let Some(mut secs) = self.secs.checked_add(rhs.secs) {
401 let mut nanos = self.nanos + rhs.nanos;
402 if nanos >= NANOS_PER_SEC {
403 nanos -= NANOS_PER_SEC;
404 if let Some(new_secs) = secs.checked_add(1) {
410 debug_assert!(nanos < NANOS_PER_SEC);
411 Some(Duration { secs, nanos })
417 /// Checked `Duration` subtraction. Computes `self - other`, returning [`None`]
418 /// if the result would be negative or if overflow occurred.
420 /// [`None`]: ../../std/option/enum.Option.html#variant.None
427 /// use std::time::Duration;
429 /// assert_eq!(Duration::new(0, 1).checked_sub(Duration::new(0, 0)), Some(Duration::new(0, 1)));
430 /// assert_eq!(Duration::new(0, 0).checked_sub(Duration::new(0, 1)), None);
432 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
434 pub fn checked_sub(self, rhs: Duration) -> Option<Duration> {
435 if let Some(mut secs) = self.secs.checked_sub(rhs.secs) {
436 let nanos = if self.nanos >= rhs.nanos {
437 self.nanos - rhs.nanos
439 if let Some(sub_secs) = secs.checked_sub(1) {
441 self.nanos + NANOS_PER_SEC - rhs.nanos
446 debug_assert!(nanos < NANOS_PER_SEC);
447 Some(Duration { secs, nanos })
453 /// Checked `Duration` multiplication. Computes `self * other`, returning
454 /// [`None`] if overflow occurred.
456 /// [`None`]: ../../std/option/enum.Option.html#variant.None
463 /// use std::time::Duration;
465 /// assert_eq!(Duration::new(0, 500_000_001).checked_mul(2), Some(Duration::new(1, 2)));
466 /// assert_eq!(Duration::new(std::u64::MAX - 1, 0).checked_mul(2), None);
468 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
470 pub fn checked_mul(self, rhs: u32) -> Option<Duration> {
471 // Multiply nanoseconds as u64, because it cannot overflow that way.
472 let total_nanos = self.nanos as u64 * rhs as u64;
473 let extra_secs = total_nanos / (NANOS_PER_SEC as u64);
474 let nanos = (total_nanos % (NANOS_PER_SEC as u64)) as u32;
476 self.secs.checked_mul(rhs as u64).and_then(|s| s.checked_add(extra_secs))
478 debug_assert!(nanos < NANOS_PER_SEC);
479 Some(Duration { secs, nanos })
485 /// Checked `Duration` division. Computes `self / other`, returning [`None`]
488 /// [`None`]: ../../std/option/enum.Option.html#variant.None
495 /// use std::time::Duration;
497 /// assert_eq!(Duration::new(2, 0).checked_div(2), Some(Duration::new(1, 0)));
498 /// assert_eq!(Duration::new(1, 0).checked_div(2), Some(Duration::new(0, 500_000_000)));
499 /// assert_eq!(Duration::new(2, 0).checked_div(0), None);
501 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
503 pub fn checked_div(self, rhs: u32) -> Option<Duration> {
505 let secs = self.secs / (rhs as u64);
506 let carry = self.secs - secs * (rhs as u64);
507 let extra_nanos = carry * (NANOS_PER_SEC as u64) / (rhs as u64);
508 let nanos = self.nanos / rhs + (extra_nanos as u32);
509 debug_assert!(nanos < NANOS_PER_SEC);
510 Some(Duration { secs, nanos })
516 /// Returns the number of seconds contained by this `Duration` as `f64`.
518 /// The returned value does include the fractional (nanosecond) part of the duration.
522 /// use std::time::Duration;
524 /// let dur = Duration::new(2, 700_000_000);
525 /// assert_eq!(dur.as_secs_f64(), 2.7);
527 #[stable(feature = "duration_float", since = "1.38.0")]
529 pub fn as_secs_f64(&self) -> f64 {
530 (self.secs as f64) + (self.nanos as f64) / (NANOS_PER_SEC as f64)
533 /// Returns the number of seconds contained by this `Duration` as `f32`.
535 /// The returned value does include the fractional (nanosecond) part of the duration.
539 /// use std::time::Duration;
541 /// let dur = Duration::new(2, 700_000_000);
542 /// assert_eq!(dur.as_secs_f32(), 2.7);
544 #[stable(feature = "duration_float", since = "1.38.0")]
546 pub fn as_secs_f32(&self) -> f32 {
547 (self.secs as f32) + (self.nanos as f32) / (NANOS_PER_SEC as f32)
550 /// Creates a new `Duration` from the specified number of seconds represented
554 /// This constructor will panic if `secs` is not finite, negative or overflows `Duration`.
558 /// use std::time::Duration;
560 /// let dur = Duration::from_secs_f64(2.7);
561 /// assert_eq!(dur, Duration::new(2, 700_000_000));
563 #[stable(feature = "duration_float", since = "1.38.0")]
565 pub fn from_secs_f64(secs: f64) -> Duration {
566 const MAX_NANOS_F64: f64 = ((u64::MAX as u128 + 1) * (NANOS_PER_SEC as u128)) as f64;
567 let nanos = secs * (NANOS_PER_SEC as f64);
568 if !nanos.is_finite() {
569 panic!("got non-finite value when converting float to duration");
571 if nanos >= MAX_NANOS_F64 {
572 panic!("overflow when converting float to duration");
575 panic!("underflow when converting float to duration");
577 let nanos = nanos as u128;
579 secs: (nanos / (NANOS_PER_SEC as u128)) as u64,
580 nanos: (nanos % (NANOS_PER_SEC as u128)) as u32,
584 /// Creates a new `Duration` from the specified number of seconds represented
588 /// This constructor will panic if `secs` is not finite, negative or overflows `Duration`.
592 /// use std::time::Duration;
594 /// let dur = Duration::from_secs_f32(2.7);
595 /// assert_eq!(dur, Duration::new(2, 700_000_000));
597 #[stable(feature = "duration_float", since = "1.38.0")]
599 pub fn from_secs_f32(secs: f32) -> Duration {
600 const MAX_NANOS_F32: f32 = ((u64::MAX as u128 + 1) * (NANOS_PER_SEC as u128)) as f32;
601 let nanos = secs * (NANOS_PER_SEC as f32);
602 if !nanos.is_finite() {
603 panic!("got non-finite value when converting float to duration");
605 if nanos >= MAX_NANOS_F32 {
606 panic!("overflow when converting float to duration");
609 panic!("underflow when converting float to duration");
611 let nanos = nanos as u128;
613 secs: (nanos / (NANOS_PER_SEC as u128)) as u64,
614 nanos: (nanos % (NANOS_PER_SEC as u128)) as u32,
618 /// Multiplies `Duration` by `f64`.
621 /// This method will panic if result is not finite, negative or overflows `Duration`.
625 /// use std::time::Duration;
627 /// let dur = Duration::new(2, 700_000_000);
628 /// assert_eq!(dur.mul_f64(3.14), Duration::new(8, 478_000_000));
629 /// assert_eq!(dur.mul_f64(3.14e5), Duration::new(847_800, 0));
631 #[stable(feature = "duration_float", since = "1.38.0")]
633 pub fn mul_f64(self, rhs: f64) -> Duration {
634 Duration::from_secs_f64(rhs * self.as_secs_f64())
637 /// Multiplies `Duration` by `f32`.
640 /// This method will panic if result is not finite, negative or overflows `Duration`.
644 /// use std::time::Duration;
646 /// let dur = Duration::new(2, 700_000_000);
647 /// // note that due to rounding errors result is slightly different
648 /// // from 8.478 and 847800.0
649 /// assert_eq!(dur.mul_f32(3.14), Duration::new(8, 478_000_640));
650 /// assert_eq!(dur.mul_f32(3.14e5), Duration::new(847799, 969_120_256));
652 #[stable(feature = "duration_float", since = "1.38.0")]
654 pub fn mul_f32(self, rhs: f32) -> Duration {
655 Duration::from_secs_f32(rhs * self.as_secs_f32())
658 /// Divide `Duration` by `f64`.
661 /// This method will panic if result is not finite, negative or overflows `Duration`.
665 /// use std::time::Duration;
667 /// let dur = Duration::new(2, 700_000_000);
668 /// assert_eq!(dur.div_f64(3.14), Duration::new(0, 859_872_611));
669 /// // note that truncation is used, not rounding
670 /// assert_eq!(dur.div_f64(3.14e5), Duration::new(0, 8_598));
672 #[stable(feature = "duration_float", since = "1.38.0")]
674 pub fn div_f64(self, rhs: f64) -> Duration {
675 Duration::from_secs_f64(self.as_secs_f64() / rhs)
678 /// Divide `Duration` by `f32`.
681 /// This method will panic if result is not finite, negative or overflows `Duration`.
685 /// use std::time::Duration;
687 /// let dur = Duration::new(2, 700_000_000);
688 /// // note that due to rounding errors result is slightly
689 /// // different from 0.859_872_611
690 /// assert_eq!(dur.div_f32(3.14), Duration::new(0, 859_872_576));
691 /// // note that truncation is used, not rounding
692 /// assert_eq!(dur.div_f32(3.14e5), Duration::new(0, 8_598));
694 #[stable(feature = "duration_float", since = "1.38.0")]
696 pub fn div_f32(self, rhs: f32) -> Duration {
697 Duration::from_secs_f32(self.as_secs_f32() / rhs)
700 /// Divide `Duration` by `Duration` and return `f64`.
704 /// #![feature(div_duration)]
705 /// use std::time::Duration;
707 /// let dur1 = Duration::new(2, 700_000_000);
708 /// let dur2 = Duration::new(5, 400_000_000);
709 /// assert_eq!(dur1.div_duration_f64(dur2), 0.5);
711 #[unstable(feature = "div_duration", issue = "63139")]
713 pub fn div_duration_f64(self, rhs: Duration) -> f64 {
714 self.as_secs_f64() / rhs.as_secs_f64()
717 /// Divide `Duration` by `Duration` and return `f32`.
721 /// #![feature(div_duration)]
722 /// use std::time::Duration;
724 /// let dur1 = Duration::new(2, 700_000_000);
725 /// let dur2 = Duration::new(5, 400_000_000);
726 /// assert_eq!(dur1.div_duration_f32(dur2), 0.5);
728 #[unstable(feature = "div_duration", issue = "63139")]
730 pub fn div_duration_f32(self, rhs: Duration) -> f32 {
731 self.as_secs_f32() / rhs.as_secs_f32()
735 #[stable(feature = "duration", since = "1.3.0")]
736 impl Add for Duration {
737 type Output = Duration;
739 fn add(self, rhs: Duration) -> Duration {
740 self.checked_add(rhs).expect("overflow when adding durations")
744 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
745 impl AddAssign for Duration {
746 fn add_assign(&mut self, rhs: Duration) {
751 #[stable(feature = "duration", since = "1.3.0")]
752 impl Sub for Duration {
753 type Output = Duration;
755 fn sub(self, rhs: Duration) -> Duration {
756 self.checked_sub(rhs).expect("overflow when subtracting durations")
760 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
761 impl SubAssign for Duration {
762 fn sub_assign(&mut self, rhs: Duration) {
767 #[stable(feature = "duration", since = "1.3.0")]
768 impl Mul<u32> for Duration {
769 type Output = Duration;
771 fn mul(self, rhs: u32) -> Duration {
772 self.checked_mul(rhs).expect("overflow when multiplying duration by scalar")
776 #[stable(feature = "symmetric_u32_duration_mul", since = "1.31.0")]
777 impl Mul<Duration> for u32 {
778 type Output = Duration;
780 fn mul(self, rhs: Duration) -> Duration {
785 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
786 impl MulAssign<u32> for Duration {
787 fn mul_assign(&mut self, rhs: u32) {
792 #[stable(feature = "duration", since = "1.3.0")]
793 impl Div<u32> for Duration {
794 type Output = Duration;
796 fn div(self, rhs: u32) -> Duration {
797 self.checked_div(rhs).expect("divide by zero error when dividing duration by scalar")
801 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
802 impl DivAssign<u32> for Duration {
803 fn div_assign(&mut self, rhs: u32) {
808 macro_rules! sum_durations {
810 let mut total_secs: u64 = 0;
811 let mut total_nanos: u64 = 0;
815 total_secs.checked_add(entry.secs).expect("overflow in iter::sum over durations");
816 total_nanos = match total_nanos.checked_add(entry.nanos as u64) {
819 total_secs = total_secs
820 .checked_add(total_nanos / NANOS_PER_SEC as u64)
821 .expect("overflow in iter::sum over durations");
822 (total_nanos % NANOS_PER_SEC as u64) + entry.nanos as u64
826 total_secs = total_secs
827 .checked_add(total_nanos / NANOS_PER_SEC as u64)
828 .expect("overflow in iter::sum over durations");
829 total_nanos = total_nanos % NANOS_PER_SEC as u64;
830 Duration { secs: total_secs, nanos: total_nanos as u32 }
834 #[stable(feature = "duration_sum", since = "1.16.0")]
835 impl Sum for Duration {
836 fn sum<I: Iterator<Item = Duration>>(iter: I) -> Duration {
841 #[stable(feature = "duration_sum", since = "1.16.0")]
842 impl<'a> Sum<&'a Duration> for Duration {
843 fn sum<I: Iterator<Item = &'a Duration>>(iter: I) -> Duration {
848 #[stable(feature = "duration_debug_impl", since = "1.27.0")]
849 impl fmt::Debug for Duration {
850 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
851 /// Formats a floating point number in decimal notation.
853 /// The number is given as the `integer_part` and a fractional part.
854 /// The value of the fractional part is `fractional_part / divisor`. So
855 /// `integer_part` = 3, `fractional_part` = 12 and `divisor` = 100
856 /// represents the number `3.012`. Trailing zeros are omitted.
858 /// `divisor` must not be above 100_000_000. It also should be a power
859 /// of 10, everything else doesn't make sense. `fractional_part` has
860 /// to be less than `10 * divisor`!
862 f: &mut fmt::Formatter<'_>,
863 mut integer_part: u64,
864 mut fractional_part: u32,
867 // Encode the fractional part into a temporary buffer. The buffer
868 // only need to hold 9 elements, because `fractional_part` has to
869 // be smaller than 10^9. The buffer is prefilled with '0' digits
870 // to simplify the code below.
871 let mut buf = [b'0'; 9];
873 // The next digit is written at this position
876 // We keep writing digits into the buffer while there are non-zero
877 // digits left and we haven't written enough digits yet.
878 while fractional_part > 0 && pos < f.precision().unwrap_or(9) {
879 // Write new digit into the buffer
880 buf[pos] = b'0' + (fractional_part / divisor) as u8;
882 fractional_part %= divisor;
887 // If a precision < 9 was specified, there may be some non-zero
888 // digits left that weren't written into the buffer. In that case we
889 // need to perform rounding to match the semantics of printing
890 // normal floating point numbers. However, we only need to do work
891 // when rounding up. This happens if the first digit of the
892 // remaining ones is >= 5.
893 if fractional_part > 0 && fractional_part >= divisor * 5 {
894 // Round up the number contained in the buffer. We go through
895 // the buffer backwards and keep track of the carry.
896 let mut rev_pos = pos;
897 let mut carry = true;
898 while carry && rev_pos > 0 {
901 // If the digit in the buffer is not '9', we just need to
902 // increment it and can stop then (since we don't have a
903 // carry anymore). Otherwise, we set it to '0' (overflow)
905 if buf[rev_pos] < b'9' {
913 // If we still have the carry bit set, that means that we set
914 // the whole buffer to '0's and need to increment the integer
921 // Determine the end of the buffer: if precision is set, we just
922 // use as many digits from the buffer (capped to 9). If it isn't
923 // set, we only use all digits up to the last non-zero one.
924 let end = f.precision().map(|p| crate::cmp::min(p, 9)).unwrap_or(pos);
926 // If we haven't emitted a single fractional digit and the precision
927 // wasn't set to a non-zero value, we don't print the decimal point.
929 write!(f, "{}", integer_part)
931 // SAFETY: We are only writing ASCII digits into the buffer and it was
932 // initialized with '0's, so it contains valid UTF8.
933 let s = unsafe { crate::str::from_utf8_unchecked(&buf[..end]) };
935 // If the user request a precision > 9, we pad '0's at the end.
936 let w = f.precision().unwrap_or(pos);
937 write!(f, "{}.{:0<width$}", integer_part, s, width = w)
941 // Print leading '+' sign if requested
947 fmt_decimal(f, self.secs, self.nanos, 100_000_000)?;
949 } else if self.nanos >= 1_000_000 {
950 fmt_decimal(f, self.nanos as u64 / 1_000_000, self.nanos % 1_000_000, 100_000)?;
952 } else if self.nanos >= 1_000 {
953 fmt_decimal(f, self.nanos as u64 / 1_000, self.nanos % 1_000, 100)?;
956 fmt_decimal(f, self.nanos as u64, 0, 1)?;