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));
17 use crate::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
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 #[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")]
155 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
156 pub const fn from_secs(secs: u64) -> Duration {
157 Duration { secs, nanos: 0 }
160 /// Creates a new `Duration` from the specified number of milliseconds.
165 /// use std::time::Duration;
167 /// let duration = Duration::from_millis(2569);
169 /// assert_eq!(2, duration.as_secs());
170 /// assert_eq!(569_000_000, duration.subsec_nanos());
172 #[stable(feature = "duration", since = "1.3.0")]
174 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
175 pub const fn from_millis(millis: u64) -> Duration {
177 secs: millis / MILLIS_PER_SEC,
178 nanos: ((millis % MILLIS_PER_SEC) as u32) * NANOS_PER_MILLI,
182 /// Creates a new `Duration` from the specified number of microseconds.
187 /// use std::time::Duration;
189 /// let duration = Duration::from_micros(1_000_002);
191 /// assert_eq!(1, duration.as_secs());
192 /// assert_eq!(2000, duration.subsec_nanos());
194 #[stable(feature = "duration_from_micros", since = "1.27.0")]
196 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
197 pub const fn from_micros(micros: u64) -> Duration {
199 secs: micros / MICROS_PER_SEC,
200 nanos: ((micros % MICROS_PER_SEC) as u32) * NANOS_PER_MICRO,
204 /// Creates a new `Duration` from the specified number of nanoseconds.
209 /// use std::time::Duration;
211 /// let duration = Duration::from_nanos(1_000_000_123);
213 /// assert_eq!(1, duration.as_secs());
214 /// assert_eq!(123, duration.subsec_nanos());
216 #[stable(feature = "duration_extras", since = "1.27.0")]
218 #[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
219 pub const fn from_nanos(nanos: u64) -> Duration {
221 secs: nanos / (NANOS_PER_SEC as u64),
222 nanos: (nanos % (NANOS_PER_SEC as u64)) as u32,
226 /// Returns the number of _whole_ seconds contained by this `Duration`.
228 /// The returned value does not include the fractional (nanosecond) part of the
229 /// duration, which can be obtained using [`subsec_nanos`].
234 /// use std::time::Duration;
236 /// let duration = Duration::new(5, 730023852);
237 /// assert_eq!(duration.as_secs(), 5);
240 /// To determine the total number of seconds represented by the `Duration`,
241 /// use `as_secs` in combination with [`subsec_nanos`]:
244 /// use std::time::Duration;
246 /// let duration = Duration::new(5, 730023852);
248 /// assert_eq!(5.730023852,
249 /// duration.as_secs() as f64
250 /// + duration.subsec_nanos() as f64 * 1e-9);
253 /// [`subsec_nanos`]: #method.subsec_nanos
254 #[stable(feature = "duration", since = "1.3.0")]
255 #[rustc_const_stable(feature = "duration", since = "1.32.0")]
257 pub const fn as_secs(&self) -> u64 {
261 /// Returns the fractional part of this `Duration`, in whole milliseconds.
263 /// This method does **not** return the length of the duration when
264 /// represented by milliseconds. The returned number always represents a
265 /// fractional portion of a second (i.e., it is less than one thousand).
270 /// use std::time::Duration;
272 /// let duration = Duration::from_millis(5432);
273 /// assert_eq!(duration.as_secs(), 5);
274 /// assert_eq!(duration.subsec_millis(), 432);
276 #[stable(feature = "duration_extras", since = "1.27.0")]
277 #[rustc_const_stable(feature = "duration_extras", since = "1.32.0")]
279 pub const fn subsec_millis(&self) -> u32 {
280 self.nanos / NANOS_PER_MILLI
283 /// Returns the fractional part of this `Duration`, in whole microseconds.
285 /// This method does **not** return the length of the duration when
286 /// represented by microseconds. The returned number always represents a
287 /// fractional portion of a second (i.e., it is less than one million).
292 /// use std::time::Duration;
294 /// let duration = Duration::from_micros(1_234_567);
295 /// assert_eq!(duration.as_secs(), 1);
296 /// assert_eq!(duration.subsec_micros(), 234_567);
298 #[stable(feature = "duration_extras", since = "1.27.0")]
299 #[rustc_const_stable(feature = "duration_extras", since = "1.32.0")]
301 pub const fn subsec_micros(&self) -> u32 {
302 self.nanos / NANOS_PER_MICRO
305 /// Returns the fractional part of this `Duration`, in nanoseconds.
307 /// This method does **not** return the length of the duration when
308 /// represented by nanoseconds. The returned number always represents a
309 /// fractional portion of a second (i.e., it is less than one billion).
314 /// use std::time::Duration;
316 /// let duration = Duration::from_millis(5010);
317 /// assert_eq!(duration.as_secs(), 5);
318 /// assert_eq!(duration.subsec_nanos(), 10_000_000);
320 #[stable(feature = "duration", since = "1.3.0")]
321 #[rustc_const_stable(feature = "duration", since = "1.32.0")]
323 pub const fn subsec_nanos(&self) -> u32 {
327 /// Returns the total number of whole milliseconds contained by this `Duration`.
332 /// use std::time::Duration;
334 /// let duration = Duration::new(5, 730023852);
335 /// assert_eq!(duration.as_millis(), 5730);
337 #[stable(feature = "duration_as_u128", since = "1.33.0")]
338 #[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
340 pub const fn as_millis(&self) -> u128 {
341 self.secs as u128 * MILLIS_PER_SEC as u128 + (self.nanos / NANOS_PER_MILLI) as u128
344 /// Returns the total number of whole microseconds contained by this `Duration`.
349 /// use std::time::Duration;
351 /// let duration = Duration::new(5, 730023852);
352 /// assert_eq!(duration.as_micros(), 5730023);
354 #[stable(feature = "duration_as_u128", since = "1.33.0")]
355 #[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
357 pub const fn as_micros(&self) -> u128 {
358 self.secs as u128 * MICROS_PER_SEC as u128 + (self.nanos / NANOS_PER_MICRO) as u128
361 /// Returns the total number of nanoseconds contained by this `Duration`.
366 /// use std::time::Duration;
368 /// let duration = Duration::new(5, 730023852);
369 /// assert_eq!(duration.as_nanos(), 5730023852);
371 #[stable(feature = "duration_as_u128", since = "1.33.0")]
372 #[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
374 pub const fn as_nanos(&self) -> u128 {
375 self.secs as u128 * NANOS_PER_SEC as u128 + self.nanos as u128
378 /// Checked `Duration` addition. Computes `self + other`, returning [`None`]
379 /// if overflow occurred.
381 /// [`None`]: ../../std/option/enum.Option.html#variant.None
388 /// use std::time::Duration;
390 /// assert_eq!(Duration::new(0, 0).checked_add(Duration::new(0, 1)), Some(Duration::new(0, 1)));
391 /// assert_eq!(Duration::new(1, 0).checked_add(Duration::new(u64::MAX, 0)), None);
393 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
395 pub fn checked_add(self, rhs: Duration) -> Option<Duration> {
396 if let Some(mut secs) = self.secs.checked_add(rhs.secs) {
397 let mut nanos = self.nanos + rhs.nanos;
398 if nanos >= NANOS_PER_SEC {
399 nanos -= NANOS_PER_SEC;
400 if let Some(new_secs) = secs.checked_add(1) {
406 debug_assert!(nanos < NANOS_PER_SEC);
407 Some(Duration { secs, nanos })
413 /// Checked `Duration` subtraction. Computes `self - other`, returning [`None`]
414 /// if the result would be negative or if overflow occurred.
416 /// [`None`]: ../../std/option/enum.Option.html#variant.None
423 /// use std::time::Duration;
425 /// assert_eq!(Duration::new(0, 1).checked_sub(Duration::new(0, 0)), Some(Duration::new(0, 1)));
426 /// assert_eq!(Duration::new(0, 0).checked_sub(Duration::new(0, 1)), None);
428 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
430 pub fn checked_sub(self, rhs: Duration) -> Option<Duration> {
431 if let Some(mut secs) = self.secs.checked_sub(rhs.secs) {
432 let nanos = if self.nanos >= rhs.nanos {
433 self.nanos - rhs.nanos
435 if let Some(sub_secs) = secs.checked_sub(1) {
437 self.nanos + NANOS_PER_SEC - rhs.nanos
442 debug_assert!(nanos < NANOS_PER_SEC);
443 Some(Duration { secs, nanos })
449 /// Checked `Duration` multiplication. Computes `self * other`, returning
450 /// [`None`] if overflow occurred.
452 /// [`None`]: ../../std/option/enum.Option.html#variant.None
459 /// use std::time::Duration;
461 /// assert_eq!(Duration::new(0, 500_000_001).checked_mul(2), Some(Duration::new(1, 2)));
462 /// assert_eq!(Duration::new(u64::MAX - 1, 0).checked_mul(2), None);
464 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
466 pub fn checked_mul(self, rhs: u32) -> Option<Duration> {
467 // Multiply nanoseconds as u64, because it cannot overflow that way.
468 let total_nanos = self.nanos as u64 * rhs as u64;
469 let extra_secs = total_nanos / (NANOS_PER_SEC as u64);
470 let nanos = (total_nanos % (NANOS_PER_SEC as u64)) as u32;
472 self.secs.checked_mul(rhs as u64).and_then(|s| s.checked_add(extra_secs))
474 debug_assert!(nanos < NANOS_PER_SEC);
475 Some(Duration { secs, nanos })
481 /// Checked `Duration` division. Computes `self / other`, returning [`None`]
484 /// [`None`]: ../../std/option/enum.Option.html#variant.None
491 /// use std::time::Duration;
493 /// assert_eq!(Duration::new(2, 0).checked_div(2), Some(Duration::new(1, 0)));
494 /// assert_eq!(Duration::new(1, 0).checked_div(2), Some(Duration::new(0, 500_000_000)));
495 /// assert_eq!(Duration::new(2, 0).checked_div(0), None);
497 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
499 pub fn checked_div(self, rhs: u32) -> Option<Duration> {
501 let secs = self.secs / (rhs as u64);
502 let carry = self.secs - secs * (rhs as u64);
503 let extra_nanos = carry * (NANOS_PER_SEC as u64) / (rhs as u64);
504 let nanos = self.nanos / rhs + (extra_nanos as u32);
505 debug_assert!(nanos < NANOS_PER_SEC);
506 Some(Duration { secs, nanos })
512 /// Returns the number of seconds contained by this `Duration` as `f64`.
514 /// The returned value does include the fractional (nanosecond) part of the duration.
518 /// use std::time::Duration;
520 /// let dur = Duration::new(2, 700_000_000);
521 /// assert_eq!(dur.as_secs_f64(), 2.7);
523 #[stable(feature = "duration_float", since = "1.38.0")]
525 pub fn as_secs_f64(&self) -> f64 {
526 (self.secs as f64) + (self.nanos as f64) / (NANOS_PER_SEC as f64)
529 /// Returns the number of seconds contained by this `Duration` as `f32`.
531 /// The returned value does include the fractional (nanosecond) part of the duration.
535 /// use std::time::Duration;
537 /// let dur = Duration::new(2, 700_000_000);
538 /// assert_eq!(dur.as_secs_f32(), 2.7);
540 #[stable(feature = "duration_float", since = "1.38.0")]
542 pub fn as_secs_f32(&self) -> f32 {
543 (self.secs as f32) + (self.nanos as f32) / (NANOS_PER_SEC as f32)
546 /// Creates a new `Duration` from the specified number of seconds represented
550 /// This constructor will panic if `secs` is not finite, negative or overflows `Duration`.
554 /// use std::time::Duration;
556 /// let dur = Duration::from_secs_f64(2.7);
557 /// assert_eq!(dur, Duration::new(2, 700_000_000));
559 #[stable(feature = "duration_float", since = "1.38.0")]
561 pub fn from_secs_f64(secs: f64) -> Duration {
562 const MAX_NANOS_F64: f64 = ((u64::MAX as u128 + 1) * (NANOS_PER_SEC as u128)) as f64;
563 let nanos = secs * (NANOS_PER_SEC as f64);
564 if !nanos.is_finite() {
565 panic!("got non-finite value when converting float to duration");
567 if nanos >= MAX_NANOS_F64 {
568 panic!("overflow when converting float to duration");
571 panic!("underflow when converting float to duration");
573 let nanos = nanos as u128;
575 secs: (nanos / (NANOS_PER_SEC as u128)) as u64,
576 nanos: (nanos % (NANOS_PER_SEC as u128)) as u32,
580 /// Creates a new `Duration` from the specified number of seconds represented
584 /// This constructor will panic if `secs` is not finite, negative or overflows `Duration`.
588 /// use std::time::Duration;
590 /// let dur = Duration::from_secs_f32(2.7);
591 /// assert_eq!(dur, Duration::new(2, 700_000_000));
593 #[stable(feature = "duration_float", since = "1.38.0")]
595 pub fn from_secs_f32(secs: f32) -> Duration {
596 const MAX_NANOS_F32: f32 = ((u64::MAX as u128 + 1) * (NANOS_PER_SEC as u128)) as f32;
597 let nanos = secs * (NANOS_PER_SEC as f32);
598 if !nanos.is_finite() {
599 panic!("got non-finite value when converting float to duration");
601 if nanos >= MAX_NANOS_F32 {
602 panic!("overflow when converting float to duration");
605 panic!("underflow when converting float to duration");
607 let nanos = nanos as u128;
609 secs: (nanos / (NANOS_PER_SEC as u128)) as u64,
610 nanos: (nanos % (NANOS_PER_SEC as u128)) as u32,
614 /// Multiplies `Duration` by `f64`.
617 /// This method will panic if result is not finite, negative or overflows `Duration`.
621 /// use std::time::Duration;
623 /// let dur = Duration::new(2, 700_000_000);
624 /// assert_eq!(dur.mul_f64(3.14), Duration::new(8, 478_000_000));
625 /// assert_eq!(dur.mul_f64(3.14e5), Duration::new(847_800, 0));
627 #[stable(feature = "duration_float", since = "1.38.0")]
629 pub fn mul_f64(self, rhs: f64) -> Duration {
630 Duration::from_secs_f64(rhs * self.as_secs_f64())
633 /// Multiplies `Duration` by `f32`.
636 /// This method will panic if result is not finite, negative or overflows `Duration`.
640 /// use std::time::Duration;
642 /// let dur = Duration::new(2, 700_000_000);
643 /// // note that due to rounding errors result is slightly different
644 /// // from 8.478 and 847800.0
645 /// assert_eq!(dur.mul_f32(3.14), Duration::new(8, 478_000_640));
646 /// assert_eq!(dur.mul_f32(3.14e5), Duration::new(847799, 969_120_256));
648 #[stable(feature = "duration_float", since = "1.38.0")]
650 pub fn mul_f32(self, rhs: f32) -> Duration {
651 Duration::from_secs_f32(rhs * self.as_secs_f32())
654 /// Divide `Duration` by `f64`.
657 /// This method will panic if result is not finite, negative or overflows `Duration`.
661 /// use std::time::Duration;
663 /// let dur = Duration::new(2, 700_000_000);
664 /// assert_eq!(dur.div_f64(3.14), Duration::new(0, 859_872_611));
665 /// // note that truncation is used, not rounding
666 /// assert_eq!(dur.div_f64(3.14e5), Duration::new(0, 8_598));
668 #[stable(feature = "duration_float", since = "1.38.0")]
670 pub fn div_f64(self, rhs: f64) -> Duration {
671 Duration::from_secs_f64(self.as_secs_f64() / rhs)
674 /// Divide `Duration` by `f32`.
677 /// This method will panic if result is not finite, negative or overflows `Duration`.
681 /// use std::time::Duration;
683 /// let dur = Duration::new(2, 700_000_000);
684 /// // note that due to rounding errors result is slightly
685 /// // different from 0.859_872_611
686 /// assert_eq!(dur.div_f32(3.14), Duration::new(0, 859_872_576));
687 /// // note that truncation is used, not rounding
688 /// assert_eq!(dur.div_f32(3.14e5), Duration::new(0, 8_598));
690 #[stable(feature = "duration_float", since = "1.38.0")]
692 pub fn div_f32(self, rhs: f32) -> Duration {
693 Duration::from_secs_f32(self.as_secs_f32() / rhs)
696 /// Divide `Duration` by `Duration` and return `f64`.
700 /// #![feature(div_duration)]
701 /// use std::time::Duration;
703 /// let dur1 = Duration::new(2, 700_000_000);
704 /// let dur2 = Duration::new(5, 400_000_000);
705 /// assert_eq!(dur1.div_duration_f64(dur2), 0.5);
707 #[unstable(feature = "div_duration", issue = "63139")]
709 pub fn div_duration_f64(self, rhs: Duration) -> f64 {
710 self.as_secs_f64() / rhs.as_secs_f64()
713 /// Divide `Duration` by `Duration` and return `f32`.
717 /// #![feature(div_duration)]
718 /// use std::time::Duration;
720 /// let dur1 = Duration::new(2, 700_000_000);
721 /// let dur2 = Duration::new(5, 400_000_000);
722 /// assert_eq!(dur1.div_duration_f32(dur2), 0.5);
724 #[unstable(feature = "div_duration", issue = "63139")]
726 pub fn div_duration_f32(self, rhs: Duration) -> f32 {
727 self.as_secs_f32() / rhs.as_secs_f32()
731 #[stable(feature = "duration", since = "1.3.0")]
732 impl Add for Duration {
733 type Output = Duration;
735 fn add(self, rhs: Duration) -> Duration {
736 self.checked_add(rhs).expect("overflow when adding durations")
740 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
741 impl AddAssign for Duration {
742 fn add_assign(&mut self, rhs: Duration) {
747 #[stable(feature = "duration", since = "1.3.0")]
748 impl Sub for Duration {
749 type Output = Duration;
751 fn sub(self, rhs: Duration) -> Duration {
752 self.checked_sub(rhs).expect("overflow when subtracting durations")
756 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
757 impl SubAssign for Duration {
758 fn sub_assign(&mut self, rhs: Duration) {
763 #[stable(feature = "duration", since = "1.3.0")]
764 impl Mul<u32> for Duration {
765 type Output = Duration;
767 fn mul(self, rhs: u32) -> Duration {
768 self.checked_mul(rhs).expect("overflow when multiplying duration by scalar")
772 #[stable(feature = "symmetric_u32_duration_mul", since = "1.31.0")]
773 impl Mul<Duration> for u32 {
774 type Output = Duration;
776 fn mul(self, rhs: Duration) -> Duration {
781 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
782 impl MulAssign<u32> for Duration {
783 fn mul_assign(&mut self, rhs: u32) {
788 #[stable(feature = "duration", since = "1.3.0")]
789 impl Div<u32> for Duration {
790 type Output = Duration;
792 fn div(self, rhs: u32) -> Duration {
793 self.checked_div(rhs).expect("divide by zero error when dividing duration by scalar")
797 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
798 impl DivAssign<u32> for Duration {
799 fn div_assign(&mut self, rhs: u32) {
804 macro_rules! sum_durations {
806 let mut total_secs: u64 = 0;
807 let mut total_nanos: u64 = 0;
811 total_secs.checked_add(entry.secs).expect("overflow in iter::sum over durations");
812 total_nanos = match total_nanos.checked_add(entry.nanos as u64) {
815 total_secs = total_secs
816 .checked_add(total_nanos / NANOS_PER_SEC as u64)
817 .expect("overflow in iter::sum over durations");
818 (total_nanos % NANOS_PER_SEC as u64) + entry.nanos as u64
822 total_secs = total_secs
823 .checked_add(total_nanos / NANOS_PER_SEC as u64)
824 .expect("overflow in iter::sum over durations");
825 total_nanos = total_nanos % NANOS_PER_SEC as u64;
826 Duration { secs: total_secs, nanos: total_nanos as u32 }
830 #[stable(feature = "duration_sum", since = "1.16.0")]
831 impl Sum for Duration {
832 fn sum<I: Iterator<Item = Duration>>(iter: I) -> Duration {
837 #[stable(feature = "duration_sum", since = "1.16.0")]
838 impl<'a> Sum<&'a Duration> for Duration {
839 fn sum<I: Iterator<Item = &'a Duration>>(iter: I) -> Duration {
844 #[stable(feature = "duration_debug_impl", since = "1.27.0")]
845 impl fmt::Debug for Duration {
846 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
847 /// Formats a floating point number in decimal notation.
849 /// The number is given as the `integer_part` and a fractional part.
850 /// The value of the fractional part is `fractional_part / divisor`. So
851 /// `integer_part` = 3, `fractional_part` = 12 and `divisor` = 100
852 /// represents the number `3.012`. Trailing zeros are omitted.
854 /// `divisor` must not be above 100_000_000. It also should be a power
855 /// of 10, everything else doesn't make sense. `fractional_part` has
856 /// to be less than `10 * divisor`!
858 f: &mut fmt::Formatter<'_>,
859 mut integer_part: u64,
860 mut fractional_part: u32,
863 // Encode the fractional part into a temporary buffer. The buffer
864 // only need to hold 9 elements, because `fractional_part` has to
865 // be smaller than 10^9. The buffer is prefilled with '0' digits
866 // to simplify the code below.
867 let mut buf = [b'0'; 9];
869 // The next digit is written at this position
872 // We keep writing digits into the buffer while there are non-zero
873 // digits left and we haven't written enough digits yet.
874 while fractional_part > 0 && pos < f.precision().unwrap_or(9) {
875 // Write new digit into the buffer
876 buf[pos] = b'0' + (fractional_part / divisor) as u8;
878 fractional_part %= divisor;
883 // If a precision < 9 was specified, there may be some non-zero
884 // digits left that weren't written into the buffer. In that case we
885 // need to perform rounding to match the semantics of printing
886 // normal floating point numbers. However, we only need to do work
887 // when rounding up. This happens if the first digit of the
888 // remaining ones is >= 5.
889 if fractional_part > 0 && fractional_part >= divisor * 5 {
890 // Round up the number contained in the buffer. We go through
891 // the buffer backwards and keep track of the carry.
892 let mut rev_pos = pos;
893 let mut carry = true;
894 while carry && rev_pos > 0 {
897 // If the digit in the buffer is not '9', we just need to
898 // increment it and can stop then (since we don't have a
899 // carry anymore). Otherwise, we set it to '0' (overflow)
901 if buf[rev_pos] < b'9' {
909 // If we still have the carry bit set, that means that we set
910 // the whole buffer to '0's and need to increment the integer
917 // Determine the end of the buffer: if precision is set, we just
918 // use as many digits from the buffer (capped to 9). If it isn't
919 // set, we only use all digits up to the last non-zero one.
920 let end = f.precision().map(|p| crate::cmp::min(p, 9)).unwrap_or(pos);
922 // If we haven't emitted a single fractional digit and the precision
923 // wasn't set to a non-zero value, we don't print the decimal point.
925 write!(f, "{}", integer_part)
927 // SAFETY: We are only writing ASCII digits into the buffer and it was
928 // initialized with '0's, so it contains valid UTF8.
929 let s = unsafe { crate::str::from_utf8_unchecked(&buf[..end]) };
931 // If the user request a precision > 9, we pad '0's at the end.
932 let w = f.precision().unwrap_or(pos);
933 write!(f, "{}.{:0<width$}", integer_part, s, width = w)
937 // Print leading '+' sign if requested
943 fmt_decimal(f, self.secs, self.nanos, 100_000_000)?;
945 } else if self.nanos >= 1_000_000 {
946 fmt_decimal(f, self.nanos as u64 / 1_000_000, self.nanos % 1_000_000, 100_000)?;
948 } else if self.nanos >= 1_000 {
949 fmt_decimal(f, self.nanos as u64 / 1_000, self.nanos % 1_000, 100)?;
952 fmt_decimal(f, self.nanos as u64, 0, 1)?;