1 // Copyright 2012-2017 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
10 #![stable(feature = "duration_core", since = "1.25.0")]
12 //! Temporal quantification.
17 //! use std::time::Duration;
19 //! let five_seconds = Duration::new(5, 0);
20 //! // both declarations are equivalent
21 //! assert_eq!(Duration::new(5, 0), Duration::from_secs(5));
26 use ops::{Add, Sub, Mul, Div, AddAssign, SubAssign, MulAssign, DivAssign};
28 const NANOS_PER_SEC: u32 = 1_000_000_000;
29 const NANOS_PER_MILLI: u32 = 1_000_000;
30 const NANOS_PER_MICRO: u32 = 1_000;
31 const MILLIS_PER_SEC: u64 = 1_000;
32 const MICROS_PER_SEC: u64 = 1_000_000;
33 const MAX_NANOS_F64: f64 = ((u64::MAX as u128 + 1)*(NANOS_PER_SEC as u128)) as f64;
35 /// A `Duration` type to represent a span of time, typically used for system
38 /// Each `Duration` is composed of a whole number of seconds and a fractional part
39 /// represented in nanoseconds. If the underlying system does not support
40 /// nanosecond-level precision, APIs binding a system timeout will typically round up
41 /// the number of nanoseconds.
43 /// `Duration`s implement many common traits, including [`Add`], [`Sub`], and other
46 /// [`Add`]: ../../std/ops/trait.Add.html
47 /// [`Sub`]: ../../std/ops/trait.Sub.html
48 /// [`ops`]: ../../std/ops/index.html
53 /// use std::time::Duration;
55 /// let five_seconds = Duration::new(5, 0);
56 /// let five_seconds_and_five_nanos = five_seconds + Duration::new(0, 5);
58 /// assert_eq!(five_seconds_and_five_nanos.as_secs(), 5);
59 /// assert_eq!(five_seconds_and_five_nanos.subsec_nanos(), 5);
61 /// let ten_millis = Duration::from_millis(10);
63 #[stable(feature = "duration", since = "1.3.0")]
64 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
67 nanos: u32, // Always 0 <= nanos < NANOS_PER_SEC
71 /// Creates a new `Duration` from the specified number of whole seconds and
72 /// additional nanoseconds.
74 /// If the number of nanoseconds is greater than 1 billion (the number of
75 /// nanoseconds in a second), then it will carry over into the seconds provided.
79 /// This constructor will panic if the carry from the nanoseconds overflows
80 /// the seconds counter.
85 /// use std::time::Duration;
87 /// let five_seconds = Duration::new(5, 0);
89 #[stable(feature = "duration", since = "1.3.0")]
91 pub fn new(secs: u64, nanos: u32) -> Duration {
92 let secs = secs.checked_add((nanos / NANOS_PER_SEC) as u64)
93 .expect("overflow in Duration::new");
94 let nanos = nanos % NANOS_PER_SEC;
95 Duration { secs, nanos }
98 /// Creates a new `Duration` from the specified number of whole seconds.
103 /// use std::time::Duration;
105 /// let duration = Duration::from_secs(5);
107 /// assert_eq!(5, duration.as_secs());
108 /// assert_eq!(0, duration.subsec_nanos());
110 #[stable(feature = "duration", since = "1.3.0")]
113 pub const fn from_secs(secs: u64) -> Duration {
114 Duration { secs, nanos: 0 }
117 /// Creates a new `Duration` from the specified number of milliseconds.
122 /// use std::time::Duration;
124 /// let duration = Duration::from_millis(2569);
126 /// assert_eq!(2, duration.as_secs());
127 /// assert_eq!(569_000_000, duration.subsec_nanos());
129 #[stable(feature = "duration", since = "1.3.0")]
132 pub const fn from_millis(millis: u64) -> Duration {
134 secs: millis / MILLIS_PER_SEC,
135 nanos: ((millis % MILLIS_PER_SEC) as u32) * NANOS_PER_MILLI,
139 /// Creates a new `Duration` from the specified number of microseconds.
144 /// use std::time::Duration;
146 /// let duration = Duration::from_micros(1_000_002);
148 /// assert_eq!(1, duration.as_secs());
149 /// assert_eq!(2000, duration.subsec_nanos());
151 #[stable(feature = "duration_from_micros", since = "1.27.0")]
154 pub const fn from_micros(micros: u64) -> Duration {
156 secs: micros / MICROS_PER_SEC,
157 nanos: ((micros % MICROS_PER_SEC) as u32) * NANOS_PER_MICRO,
161 /// Creates a new `Duration` from the specified number of nanoseconds.
166 /// use std::time::Duration;
168 /// let duration = Duration::from_nanos(1_000_000_123);
170 /// assert_eq!(1, duration.as_secs());
171 /// assert_eq!(123, duration.subsec_nanos());
173 #[stable(feature = "duration_extras", since = "1.27.0")]
176 pub const fn from_nanos(nanos: u64) -> Duration {
178 secs: nanos / (NANOS_PER_SEC as u64),
179 nanos: (nanos % (NANOS_PER_SEC as u64)) as u32,
183 /// Returns the number of _whole_ seconds contained by this `Duration`.
185 /// The returned value does not include the fractional (nanosecond) part of the
186 /// duration, which can be obtained using [`subsec_nanos`].
191 /// use std::time::Duration;
193 /// let duration = Duration::new(5, 730023852);
194 /// assert_eq!(duration.as_secs(), 5);
197 /// To determine the total number of seconds represented by the `Duration`,
198 /// use `as_secs` in combination with [`subsec_nanos`]:
201 /// use std::time::Duration;
203 /// let duration = Duration::new(5, 730023852);
205 /// assert_eq!(5.730023852,
206 /// duration.as_secs() as f64
207 /// + duration.subsec_nanos() as f64 * 1e-9);
210 /// [`subsec_nanos`]: #method.subsec_nanos
211 #[stable(feature = "duration", since = "1.3.0")]
213 pub const fn as_secs(&self) -> u64 { self.secs }
215 /// Returns the fractional part of this `Duration`, in whole milliseconds.
217 /// This method does **not** return the length of the duration when
218 /// represented by milliseconds. The returned number always represents a
219 /// fractional portion of a second (i.e. it is less than one thousand).
224 /// use std::time::Duration;
226 /// let duration = Duration::from_millis(5432);
227 /// assert_eq!(duration.as_secs(), 5);
228 /// assert_eq!(duration.subsec_millis(), 432);
230 #[stable(feature = "duration_extras", since = "1.27.0")]
232 pub const fn subsec_millis(&self) -> u32 { self.nanos / NANOS_PER_MILLI }
234 /// Returns the fractional part of this `Duration`, in whole microseconds.
236 /// This method does **not** return the length of the duration when
237 /// represented by microseconds. The returned number always represents a
238 /// fractional portion of a second (i.e. it is less than one million).
243 /// use std::time::Duration;
245 /// let duration = Duration::from_micros(1_234_567);
246 /// assert_eq!(duration.as_secs(), 1);
247 /// assert_eq!(duration.subsec_micros(), 234_567);
249 #[stable(feature = "duration_extras", since = "1.27.0")]
251 pub const fn subsec_micros(&self) -> u32 { self.nanos / NANOS_PER_MICRO }
253 /// Returns the fractional part of this `Duration`, in nanoseconds.
255 /// This method does **not** return the length of the duration when
256 /// represented by nanoseconds. The returned number always represents a
257 /// fractional portion of a second (i.e. it is less than one billion).
262 /// use std::time::Duration;
264 /// let duration = Duration::from_millis(5010);
265 /// assert_eq!(duration.as_secs(), 5);
266 /// assert_eq!(duration.subsec_nanos(), 10_000_000);
268 #[stable(feature = "duration", since = "1.3.0")]
270 pub const fn subsec_nanos(&self) -> u32 { self.nanos }
272 /// Returns the total number of whole milliseconds contained by this `Duration`.
277 /// # #![feature(duration_as_u128)]
278 /// use std::time::Duration;
280 /// let duration = Duration::new(5, 730023852);
281 /// assert_eq!(duration.as_millis(), 5730);
283 #[unstable(feature = "duration_as_u128", issue = "50202")]
285 pub const fn as_millis(&self) -> u128 {
286 self.secs as u128 * MILLIS_PER_SEC as u128 + (self.nanos / NANOS_PER_MILLI) as u128
289 /// Returns the total number of whole microseconds contained by this `Duration`.
294 /// # #![feature(duration_as_u128)]
295 /// use std::time::Duration;
297 /// let duration = Duration::new(5, 730023852);
298 /// assert_eq!(duration.as_micros(), 5730023);
300 #[unstable(feature = "duration_as_u128", issue = "50202")]
302 pub const fn as_micros(&self) -> u128 {
303 self.secs as u128 * MICROS_PER_SEC as u128 + (self.nanos / NANOS_PER_MICRO) as u128
306 /// Returns the total number of nanoseconds contained by this `Duration`.
311 /// # #![feature(duration_as_u128)]
312 /// use std::time::Duration;
314 /// let duration = Duration::new(5, 730023852);
315 /// assert_eq!(duration.as_nanos(), 5730023852);
317 #[unstable(feature = "duration_as_u128", issue = "50202")]
319 pub const fn as_nanos(&self) -> u128 {
320 self.secs as u128 * NANOS_PER_SEC as u128 + self.nanos as u128
323 /// Checked `Duration` addition. Computes `self + other`, returning [`None`]
324 /// if overflow occurred.
326 /// [`None`]: ../../std/option/enum.Option.html#variant.None
333 /// use std::time::Duration;
335 /// assert_eq!(Duration::new(0, 0).checked_add(Duration::new(0, 1)), Some(Duration::new(0, 1)));
336 /// assert_eq!(Duration::new(1, 0).checked_add(Duration::new(std::u64::MAX, 0)), None);
338 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
340 pub fn checked_add(self, rhs: Duration) -> Option<Duration> {
341 if let Some(mut secs) = self.secs.checked_add(rhs.secs) {
342 let mut nanos = self.nanos + rhs.nanos;
343 if nanos >= NANOS_PER_SEC {
344 nanos -= NANOS_PER_SEC;
345 if let Some(new_secs) = secs.checked_add(1) {
351 debug_assert!(nanos < NANOS_PER_SEC);
361 /// Checked `Duration` subtraction. Computes `self - other`, returning [`None`]
362 /// if the result would be negative or if overflow occurred.
364 /// [`None`]: ../../std/option/enum.Option.html#variant.None
371 /// use std::time::Duration;
373 /// assert_eq!(Duration::new(0, 1).checked_sub(Duration::new(0, 0)), Some(Duration::new(0, 1)));
374 /// assert_eq!(Duration::new(0, 0).checked_sub(Duration::new(0, 1)), None);
376 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
378 pub fn checked_sub(self, rhs: Duration) -> Option<Duration> {
379 if let Some(mut secs) = self.secs.checked_sub(rhs.secs) {
380 let nanos = if self.nanos >= rhs.nanos {
381 self.nanos - rhs.nanos
383 if let Some(sub_secs) = secs.checked_sub(1) {
385 self.nanos + NANOS_PER_SEC - rhs.nanos
390 debug_assert!(nanos < NANOS_PER_SEC);
391 Some(Duration { secs, nanos })
397 /// Checked `Duration` multiplication. Computes `self * other`, returning
398 /// [`None`] if overflow occurred.
400 /// [`None`]: ../../std/option/enum.Option.html#variant.None
407 /// use std::time::Duration;
409 /// assert_eq!(Duration::new(0, 500_000_001).checked_mul(2), Some(Duration::new(1, 2)));
410 /// assert_eq!(Duration::new(std::u64::MAX - 1, 0).checked_mul(2), None);
412 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
414 pub fn checked_mul(self, rhs: u32) -> Option<Duration> {
415 // Multiply nanoseconds as u64, because it cannot overflow that way.
416 let total_nanos = self.nanos as u64 * rhs as u64;
417 let extra_secs = total_nanos / (NANOS_PER_SEC as u64);
418 let nanos = (total_nanos % (NANOS_PER_SEC as u64)) as u32;
419 if let Some(secs) = self.secs
420 .checked_mul(rhs as u64)
421 .and_then(|s| s.checked_add(extra_secs)) {
422 debug_assert!(nanos < NANOS_PER_SEC);
432 /// Checked `Duration` division. Computes `self / other`, returning [`None`]
435 /// [`None`]: ../../std/option/enum.Option.html#variant.None
442 /// use std::time::Duration;
444 /// assert_eq!(Duration::new(2, 0).checked_div(2), Some(Duration::new(1, 0)));
445 /// assert_eq!(Duration::new(1, 0).checked_div(2), Some(Duration::new(0, 500_000_000)));
446 /// assert_eq!(Duration::new(2, 0).checked_div(0), None);
448 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
450 pub fn checked_div(self, rhs: u32) -> Option<Duration> {
452 let secs = self.secs / (rhs as u64);
453 let carry = self.secs - secs * (rhs as u64);
454 let extra_nanos = carry * (NANOS_PER_SEC as u64) / (rhs as u64);
455 let nanos = self.nanos / rhs + (extra_nanos as u32);
456 debug_assert!(nanos < NANOS_PER_SEC);
457 Some(Duration { secs, nanos })
463 /// Returns the number of seconds contained by this `Duration` as `f64`.
465 /// The returned value does include the fractional (nanosecond) part of the duration.
469 /// #![feature(duration_float)]
470 /// use std::time::Duration;
472 /// let dur = Duration::new(2, 700_000_000);
473 /// assert_eq!(dur.as_float_secs(), 2.7);
475 #[unstable(feature = "duration_float", issue = "54361")]
477 pub const fn as_float_secs(&self) -> f64 {
478 (self.secs as f64) + (self.nanos as f64) / (NANOS_PER_SEC as f64)
481 /// Creates a new `Duration` from the specified number of seconds.
484 /// This constructor will panic if `secs` is not finite, negative or overflows `Duration`.
488 /// #![feature(duration_float)]
489 /// use std::time::Duration;
491 /// let dur = Duration::from_float_secs(2.7);
492 /// assert_eq!(dur, Duration::new(2, 700_000_000));
494 #[unstable(feature = "duration_float", issue = "54361")]
496 pub fn from_float_secs(secs: f64) -> Duration {
497 let nanos = secs * (NANOS_PER_SEC as f64);
498 if !nanos.is_finite() {
499 panic!("got non-finite value when converting float to duration");
501 if nanos >= MAX_NANOS_F64 {
502 panic!("overflow when converting float to duration");
505 panic!("underflow when converting float to duration");
507 let nanos = nanos as u128;
509 secs: (nanos / (NANOS_PER_SEC as u128)) as u64,
510 nanos: (nanos % (NANOS_PER_SEC as u128)) as u32,
514 /// Multiply `Duration` by `f64`.
517 /// This method will panic if result is not finite, negative or overflows `Duration`.
521 /// #![feature(duration_float)]
522 /// use std::time::Duration;
524 /// let dur = Duration::new(2, 700_000_000);
525 /// assert_eq!(dur.mul_f64(3.14), Duration::new(8, 478_000_000));
526 /// assert_eq!(dur.mul_f64(3.14e5), Duration::new(847_800, 0));
528 #[unstable(feature = "duration_float", issue = "54361")]
530 pub fn mul_f64(self, rhs: f64) -> Duration {
531 Duration::from_float_secs(rhs * self.as_float_secs())
534 /// Divide `Duration` by `f64`.
537 /// This method will panic if result is not finite, negative or overflows `Duration`.
541 /// #![feature(duration_float)]
542 /// use std::time::Duration;
544 /// let dur = Duration::new(2, 700_000_000);
545 /// assert_eq!(dur.div_f64(3.14), Duration::new(0, 859_872_611));
546 /// // note that truncation is used, not rounding
547 /// assert_eq!(dur.div_f64(3.14e5), Duration::new(0, 8_598));
549 #[unstable(feature = "duration_float", issue = "54361")]
551 pub fn div_f64(self, rhs: f64) -> Duration {
552 Duration::from_float_secs(self.as_float_secs() / rhs)
555 /// Divide `Duration` by `Duration` and return `f64`.
559 /// #![feature(duration_float)]
560 /// use std::time::Duration;
562 /// let dur1 = Duration::new(2, 700_000_000);
563 /// let dur2 = Duration::new(5, 400_000_000);
564 /// assert_eq!(dur1.div_duration(dur2), 0.5);
566 #[unstable(feature = "duration_float", issue = "54361")]
568 pub fn div_duration(self, rhs: Duration) -> f64 {
569 self.as_float_secs() / rhs.as_float_secs()
573 #[stable(feature = "duration", since = "1.3.0")]
574 impl Add for Duration {
575 type Output = Duration;
577 fn add(self, rhs: Duration) -> Duration {
578 self.checked_add(rhs).expect("overflow when adding durations")
582 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
583 impl AddAssign for Duration {
584 fn add_assign(&mut self, rhs: Duration) {
589 #[stable(feature = "duration", since = "1.3.0")]
590 impl Sub for Duration {
591 type Output = Duration;
593 fn sub(self, rhs: Duration) -> Duration {
594 self.checked_sub(rhs).expect("overflow when subtracting durations")
598 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
599 impl SubAssign for Duration {
600 fn sub_assign(&mut self, rhs: Duration) {
605 #[stable(feature = "duration", since = "1.3.0")]
606 impl Mul<u32> for Duration {
607 type Output = Duration;
609 fn mul(self, rhs: u32) -> Duration {
610 self.checked_mul(rhs).expect("overflow when multiplying duration by scalar")
614 #[stable(feature = "symmetric_u32_duration_mul", since = "1.31.0")]
615 impl Mul<Duration> for u32 {
616 type Output = Duration;
618 fn mul(self, rhs: Duration) -> Duration {
623 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
624 impl MulAssign<u32> for Duration {
625 fn mul_assign(&mut self, rhs: u32) {
630 #[stable(feature = "duration", since = "1.3.0")]
631 impl Div<u32> for Duration {
632 type Output = Duration;
634 fn div(self, rhs: u32) -> Duration {
635 self.checked_div(rhs).expect("divide by zero error when dividing duration by scalar")
639 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
640 impl DivAssign<u32> for Duration {
641 fn div_assign(&mut self, rhs: u32) {
646 macro_rules! sum_durations {
648 let mut total_secs: u64 = 0;
649 let mut total_nanos: u64 = 0;
652 total_secs = total_secs
653 .checked_add(entry.secs)
654 .expect("overflow in iter::sum over durations");
655 total_nanos = match total_nanos.checked_add(entry.nanos as u64) {
658 total_secs = total_secs
659 .checked_add(total_nanos / NANOS_PER_SEC as u64)
660 .expect("overflow in iter::sum over durations");
661 (total_nanos % NANOS_PER_SEC as u64) + entry.nanos as u64
665 total_secs = total_secs
666 .checked_add(total_nanos / NANOS_PER_SEC as u64)
667 .expect("overflow in iter::sum over durations");
668 total_nanos = total_nanos % NANOS_PER_SEC as u64;
671 nanos: total_nanos as u32,
676 #[stable(feature = "duration_sum", since = "1.16.0")]
677 impl Sum for Duration {
678 fn sum<I: Iterator<Item=Duration>>(iter: I) -> Duration {
683 #[stable(feature = "duration_sum", since = "1.16.0")]
684 impl<'a> Sum<&'a Duration> for Duration {
685 fn sum<I: Iterator<Item=&'a Duration>>(iter: I) -> Duration {
690 #[stable(feature = "duration_debug_impl", since = "1.27.0")]
691 impl fmt::Debug for Duration {
692 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
693 /// Formats a floating point number in decimal notation.
695 /// The number is given as the `integer_part` and a fractional part.
696 /// The value of the fractional part is `fractional_part / divisor`. So
697 /// `integer_part` = 3, `fractional_part` = 12 and `divisor` = 100
698 /// represents the number `3.012`. Trailing zeros are omitted.
700 /// `divisor` must not be above 100_000_000. It also should be a power
701 /// of 10, everything else doesn't make sense. `fractional_part` has
702 /// to be less than `10 * divisor`!
704 f: &mut fmt::Formatter,
705 mut integer_part: u64,
706 mut fractional_part: u32,
709 // Encode the fractional part into a temporary buffer. The buffer
710 // only need to hold 9 elements, because `fractional_part` has to
711 // be smaller than 10^9. The buffer is prefilled with '0' digits
712 // to simplify the code below.
713 let mut buf = [b'0'; 9];
715 // The next digit is written at this position
718 // We keep writing digits into the buffer while there are non-zero
719 // digits left and we haven't written enough digits yet.
720 while fractional_part > 0 && pos < f.precision().unwrap_or(9) {
721 // Write new digit into the buffer
722 buf[pos] = b'0' + (fractional_part / divisor) as u8;
724 fractional_part %= divisor;
729 // If a precision < 9 was specified, there may be some non-zero
730 // digits left that weren't written into the buffer. In that case we
731 // need to perform rounding to match the semantics of printing
732 // normal floating point numbers. However, we only need to do work
733 // when rounding up. This happens if the first digit of the
734 // remaining ones is >= 5.
735 if fractional_part > 0 && fractional_part >= divisor * 5 {
736 // Round up the number contained in the buffer. We go through
737 // the buffer backwards and keep track of the carry.
738 let mut rev_pos = pos;
739 let mut carry = true;
740 while carry && rev_pos > 0 {
743 // If the digit in the buffer is not '9', we just need to
744 // increment it and can stop then (since we don't have a
745 // carry anymore). Otherwise, we set it to '0' (overflow)
747 if buf[rev_pos] < b'9' {
755 // If we still have the carry bit set, that means that we set
756 // the whole buffer to '0's and need to increment the integer
763 // Determine the end of the buffer: if precision is set, we just
764 // use as many digits from the buffer (capped to 9). If it isn't
765 // set, we only use all digits up to the last non-zero one.
766 let end = f.precision().map(|p| ::cmp::min(p, 9)).unwrap_or(pos);
768 // If we haven't emitted a single fractional digit and the precision
769 // wasn't set to a non-zero value, we don't print the decimal point.
771 write!(f, "{}", integer_part)
773 // We are only writing ASCII digits into the buffer and it was
774 // initialized with '0's, so it contains valid UTF8.
776 ::str::from_utf8_unchecked(&buf[..end])
779 // If the user request a precision > 9, we pad '0's at the end.
780 let w = f.precision().unwrap_or(pos);
781 write!(f, "{}.{:0<width$}", integer_part, s, width = w)
785 // Print leading '+' sign if requested
791 fmt_decimal(f, self.secs, self.nanos, 100_000_000)?;
793 } else if self.nanos >= 1_000_000 {
794 fmt_decimal(f, self.nanos as u64 / 1_000_000, self.nanos % 1_000_000, 100_000)?;
796 } else if self.nanos >= 1_000 {
797 fmt_decimal(f, self.nanos as u64 / 1_000, self.nanos % 1_000, 100)?;
800 fmt_decimal(f, self.nanos as u64, 0, 1)?;