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;
34 /// A `Duration` type to represent a span of time, typically used for system
37 /// Each `Duration` is composed of a whole number of seconds and a fractional part
38 /// represented in nanoseconds. If the underlying system does not support
39 /// nanosecond-level precision, APIs binding a system timeout will typically round up
40 /// the number of nanoseconds.
42 /// `Duration`s implement many common traits, including [`Add`], [`Sub`], and other
45 /// [`Add`]: ../../std/ops/trait.Add.html
46 /// [`Sub`]: ../../std/ops/trait.Sub.html
47 /// [`ops`]: ../../std/ops/index.html
52 /// use std::time::Duration;
54 /// let five_seconds = Duration::new(5, 0);
55 /// let five_seconds_and_five_nanos = five_seconds + Duration::new(0, 5);
57 /// assert_eq!(five_seconds_and_five_nanos.as_secs(), 5);
58 /// assert_eq!(five_seconds_and_five_nanos.subsec_nanos(), 5);
60 /// let ten_millis = Duration::from_millis(10);
62 #[stable(feature = "duration", since = "1.3.0")]
63 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
66 nanos: u32, // Always 0 <= nanos < NANOS_PER_SEC
70 /// Creates a new `Duration` from the specified number of whole seconds and
71 /// additional nanoseconds.
73 /// If the number of nanoseconds is greater than 1 billion (the number of
74 /// nanoseconds in a second), then it will carry over into the seconds provided.
78 /// This constructor will panic if the carry from the nanoseconds overflows
79 /// the seconds counter.
84 /// use std::time::Duration;
86 /// let five_seconds = Duration::new(5, 0);
88 #[stable(feature = "duration", since = "1.3.0")]
90 pub fn new(secs: u64, nanos: u32) -> Duration {
91 let secs = secs.checked_add((nanos / NANOS_PER_SEC) as u64)
92 .expect("overflow in Duration::new");
93 let nanos = nanos % NANOS_PER_SEC;
94 Duration { secs: secs, nanos: nanos }
97 /// Creates a new `Duration` from the specified number of whole seconds.
102 /// use std::time::Duration;
104 /// let duration = Duration::from_secs(5);
106 /// assert_eq!(5, duration.as_secs());
107 /// assert_eq!(0, duration.subsec_nanos());
109 #[stable(feature = "duration", since = "1.3.0")]
111 pub const fn from_secs(secs: u64) -> Duration {
112 Duration { secs: secs, nanos: 0 }
115 /// Creates a new `Duration` from the specified number of milliseconds.
120 /// use std::time::Duration;
122 /// let duration = Duration::from_millis(2569);
124 /// assert_eq!(2, duration.as_secs());
125 /// assert_eq!(569_000_000, duration.subsec_nanos());
127 #[stable(feature = "duration", since = "1.3.0")]
129 pub const fn from_millis(millis: u64) -> Duration {
131 secs: millis / MILLIS_PER_SEC,
132 nanos: ((millis % MILLIS_PER_SEC) as u32) * NANOS_PER_MILLI,
136 /// Creates a new `Duration` from the specified number of microseconds.
141 /// use std::time::Duration;
143 /// let duration = Duration::from_micros(1_000_002);
145 /// assert_eq!(1, duration.as_secs());
146 /// assert_eq!(2000, duration.subsec_nanos());
148 #[stable(feature = "duration_from_micros", since = "1.27.0")]
150 pub const fn from_micros(micros: u64) -> Duration {
152 secs: micros / MICROS_PER_SEC,
153 nanos: ((micros % MICROS_PER_SEC) as u32) * NANOS_PER_MICRO,
157 /// Creates a new `Duration` from the specified number of nanoseconds.
162 /// use std::time::Duration;
164 /// let duration = Duration::from_nanos(1_000_000_123);
166 /// assert_eq!(1, duration.as_secs());
167 /// assert_eq!(123, duration.subsec_nanos());
169 #[stable(feature = "duration_extras", since = "1.27.0")]
171 pub const fn from_nanos(nanos: u64) -> Duration {
173 secs: nanos / (NANOS_PER_SEC as u64),
174 nanos: (nanos % (NANOS_PER_SEC as u64)) as u32,
178 /// Returns the number of _whole_ seconds contained by this `Duration`.
180 /// The returned value does not include the fractional (nanosecond) part of the
181 /// duration, which can be obtained using [`subsec_nanos`].
186 /// use std::time::Duration;
188 /// let duration = Duration::new(5, 730023852);
189 /// assert_eq!(duration.as_secs(), 5);
192 /// To determine the total number of seconds represented by the `Duration`,
193 /// use `as_secs` in combination with [`subsec_nanos`]:
196 /// use std::time::Duration;
198 /// let duration = Duration::new(5, 730023852);
200 /// assert_eq!(5.730023852,
201 /// duration.as_secs() as f64
202 /// + duration.subsec_nanos() as f64 * 1e-9);
205 /// [`subsec_nanos`]: #method.subsec_nanos
206 #[stable(feature = "duration", since = "1.3.0")]
207 #[rustc_const_unstable(feature="duration_getters")]
209 pub const fn as_secs(&self) -> u64 { self.secs }
211 /// Returns the fractional part of this `Duration`, in whole milliseconds.
213 /// This method does **not** return the length of the duration when
214 /// represented by milliseconds. The returned number always represents a
215 /// fractional portion of a second (i.e. it is less than one thousand).
220 /// use std::time::Duration;
222 /// let duration = Duration::from_millis(5432);
223 /// assert_eq!(duration.as_secs(), 5);
224 /// assert_eq!(duration.subsec_millis(), 432);
226 #[stable(feature = "duration_extras", since = "1.27.0")]
227 #[rustc_const_unstable(feature="duration_getters")]
229 pub const fn subsec_millis(&self) -> u32 { self.nanos / NANOS_PER_MILLI }
231 /// Returns the fractional part of this `Duration`, in whole microseconds.
233 /// This method does **not** return the length of the duration when
234 /// represented by microseconds. The returned number always represents a
235 /// fractional portion of a second (i.e. it is less than one million).
240 /// use std::time::Duration;
242 /// let duration = Duration::from_micros(1_234_567);
243 /// assert_eq!(duration.as_secs(), 1);
244 /// assert_eq!(duration.subsec_micros(), 234_567);
246 #[stable(feature = "duration_extras", since = "1.27.0")]
247 #[rustc_const_unstable(feature="duration_getters")]
249 pub const fn subsec_micros(&self) -> u32 { self.nanos / NANOS_PER_MICRO }
251 /// Returns the fractional part of this `Duration`, in nanoseconds.
253 /// This method does **not** return the length of the duration when
254 /// represented by nanoseconds. The returned number always represents a
255 /// fractional portion of a second (i.e. it is less than one billion).
260 /// use std::time::Duration;
262 /// let duration = Duration::from_millis(5010);
263 /// assert_eq!(duration.as_secs(), 5);
264 /// assert_eq!(duration.subsec_nanos(), 10_000_000);
266 #[stable(feature = "duration", since = "1.3.0")]
267 #[rustc_const_unstable(feature="duration_getters")]
269 pub const fn subsec_nanos(&self) -> u32 { self.nanos }
271 /// Returns the total number of whole milliseconds contained by this `Duration`.
276 /// # #![feature(duration_as_u128)]
277 /// use std::time::Duration;
279 /// let duration = Duration::new(5, 730023852);
280 /// assert_eq!(duration.as_millis(), 5730);
282 #[unstable(feature = "duration_as_u128", issue = "50202")]
284 pub fn as_millis(&self) -> u128 {
285 self.secs as u128 * MILLIS_PER_SEC as u128 + (self.nanos / NANOS_PER_MILLI) as u128
288 /// Returns the total number of whole microseconds contained by this `Duration`.
293 /// # #![feature(duration_as_u128)]
294 /// use std::time::Duration;
296 /// let duration = Duration::new(5, 730023852);
297 /// assert_eq!(duration.as_micros(), 5730023);
299 #[unstable(feature = "duration_as_u128", issue = "50202")]
301 pub fn as_micros(&self) -> u128 {
302 self.secs as u128 * MICROS_PER_SEC as u128 + (self.nanos / NANOS_PER_MICRO) as u128
305 /// Returns the total number of nanoseconds contained by this `Duration`.
310 /// # #![feature(duration_as_u128)]
311 /// use std::time::Duration;
313 /// let duration = Duration::new(5, 730023852);
314 /// assert_eq!(duration.as_nanos(), 5730023852);
316 #[unstable(feature = "duration_as_u128", issue = "50202")]
318 pub fn as_nanos(&self) -> u128 {
319 self.secs as u128 * NANOS_PER_SEC as u128 + self.nanos as u128
322 /// Checked `Duration` addition. Computes `self + other`, returning [`None`]
323 /// if overflow occurred.
325 /// [`None`]: ../../std/option/enum.Option.html#variant.None
332 /// use std::time::Duration;
334 /// assert_eq!(Duration::new(0, 0).checked_add(Duration::new(0, 1)), Some(Duration::new(0, 1)));
335 /// assert_eq!(Duration::new(1, 0).checked_add(Duration::new(std::u64::MAX, 0)), None);
337 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
339 pub fn checked_add(self, rhs: Duration) -> Option<Duration> {
340 if let Some(mut secs) = self.secs.checked_add(rhs.secs) {
341 let mut nanos = self.nanos + rhs.nanos;
342 if nanos >= NANOS_PER_SEC {
343 nanos -= NANOS_PER_SEC;
344 if let Some(new_secs) = secs.checked_add(1) {
350 debug_assert!(nanos < NANOS_PER_SEC);
360 /// Checked `Duration` subtraction. Computes `self - other`, returning [`None`]
361 /// if the result would be negative or if overflow occurred.
363 /// [`None`]: ../../std/option/enum.Option.html#variant.None
370 /// use std::time::Duration;
372 /// assert_eq!(Duration::new(0, 1).checked_sub(Duration::new(0, 0)), Some(Duration::new(0, 1)));
373 /// assert_eq!(Duration::new(0, 0).checked_sub(Duration::new(0, 1)), None);
375 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
377 pub fn checked_sub(self, rhs: Duration) -> Option<Duration> {
378 if let Some(mut secs) = self.secs.checked_sub(rhs.secs) {
379 let nanos = if self.nanos >= rhs.nanos {
380 self.nanos - rhs.nanos
382 if let Some(sub_secs) = secs.checked_sub(1) {
384 self.nanos + NANOS_PER_SEC - rhs.nanos
389 debug_assert!(nanos < NANOS_PER_SEC);
390 Some(Duration { secs: secs, nanos: nanos })
396 /// Checked `Duration` multiplication. Computes `self * other`, returning
397 /// [`None`] if overflow occurred.
399 /// [`None`]: ../../std/option/enum.Option.html#variant.None
406 /// use std::time::Duration;
408 /// assert_eq!(Duration::new(0, 500_000_001).checked_mul(2), Some(Duration::new(1, 2)));
409 /// assert_eq!(Duration::new(std::u64::MAX - 1, 0).checked_mul(2), None);
411 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
413 pub fn checked_mul(self, rhs: u32) -> Option<Duration> {
414 // Multiply nanoseconds as u64, because it cannot overflow that way.
415 let total_nanos = self.nanos as u64 * rhs as u64;
416 let extra_secs = total_nanos / (NANOS_PER_SEC as u64);
417 let nanos = (total_nanos % (NANOS_PER_SEC as u64)) as u32;
418 if let Some(secs) = self.secs
419 .checked_mul(rhs as u64)
420 .and_then(|s| s.checked_add(extra_secs)) {
421 debug_assert!(nanos < NANOS_PER_SEC);
431 /// Checked `Duration` division. Computes `self / other`, returning [`None`]
434 /// [`None`]: ../../std/option/enum.Option.html#variant.None
441 /// use std::time::Duration;
443 /// assert_eq!(Duration::new(2, 0).checked_div(2), Some(Duration::new(1, 0)));
444 /// assert_eq!(Duration::new(1, 0).checked_div(2), Some(Duration::new(0, 500_000_000)));
445 /// assert_eq!(Duration::new(2, 0).checked_div(0), None);
447 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
449 pub fn checked_div(self, rhs: u32) -> Option<Duration> {
451 let secs = self.secs / (rhs as u64);
452 let carry = self.secs - secs * (rhs as u64);
453 let extra_nanos = carry * (NANOS_PER_SEC as u64) / (rhs as u64);
454 let nanos = self.nanos / rhs + (extra_nanos as u32);
455 debug_assert!(nanos < NANOS_PER_SEC);
456 Some(Duration { secs: secs, nanos: nanos })
463 #[stable(feature = "duration", since = "1.3.0")]
464 impl Add for Duration {
465 type Output = Duration;
467 fn add(self, rhs: Duration) -> Duration {
468 self.checked_add(rhs).expect("overflow when adding durations")
472 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
473 impl AddAssign for Duration {
474 fn add_assign(&mut self, rhs: Duration) {
479 #[stable(feature = "duration", since = "1.3.0")]
480 impl Sub for Duration {
481 type Output = Duration;
483 fn sub(self, rhs: Duration) -> Duration {
484 self.checked_sub(rhs).expect("overflow when subtracting durations")
488 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
489 impl SubAssign for Duration {
490 fn sub_assign(&mut self, rhs: Duration) {
495 #[stable(feature = "duration", since = "1.3.0")]
496 impl Mul<u32> for Duration {
497 type Output = Duration;
499 fn mul(self, rhs: u32) -> Duration {
500 self.checked_mul(rhs).expect("overflow when multiplying duration by scalar")
504 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
505 impl MulAssign<u32> for Duration {
506 fn mul_assign(&mut self, rhs: u32) {
511 #[stable(feature = "duration", since = "1.3.0")]
512 impl Div<u32> for Duration {
513 type Output = Duration;
515 fn div(self, rhs: u32) -> Duration {
516 self.checked_div(rhs).expect("divide by zero error when dividing duration by scalar")
520 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
521 impl DivAssign<u32> for Duration {
522 fn div_assign(&mut self, rhs: u32) {
527 macro_rules! sum_durations {
529 let mut total_secs: u64 = 0;
530 let mut total_nanos: u64 = 0;
533 total_secs = total_secs
534 .checked_add(entry.secs)
535 .expect("overflow in iter::sum over durations");
536 total_nanos = match total_nanos.checked_add(entry.nanos as u64) {
539 total_secs = total_secs
540 .checked_add(total_nanos / NANOS_PER_SEC as u64)
541 .expect("overflow in iter::sum over durations");
542 (total_nanos % NANOS_PER_SEC as u64) + entry.nanos as u64
546 total_secs = total_secs
547 .checked_add(total_nanos / NANOS_PER_SEC as u64)
548 .expect("overflow in iter::sum over durations");
549 total_nanos = total_nanos % NANOS_PER_SEC as u64;
552 nanos: total_nanos as u32,
557 #[stable(feature = "duration_sum", since = "1.16.0")]
558 impl Sum for Duration {
559 fn sum<I: Iterator<Item=Duration>>(iter: I) -> Duration {
564 #[stable(feature = "duration_sum", since = "1.16.0")]
565 impl<'a> Sum<&'a Duration> for Duration {
566 fn sum<I: Iterator<Item=&'a Duration>>(iter: I) -> Duration {
571 #[stable(feature = "duration_debug_impl", since = "1.27.0")]
572 impl fmt::Debug for Duration {
573 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
574 /// Formats a floating point number in decimal notation.
576 /// The number is given as the `integer_part` and a fractional part.
577 /// The value of the fractional part is `fractional_part / divisor`. So
578 /// `integer_part` = 3, `fractional_part` = 12 and `divisor` = 100
579 /// represents the number `3.012`. Trailing zeros are omitted.
581 /// `divisor` must not be above 100_000_000. It also should be a power
582 /// of 10, everything else doesn't make sense. `fractional_part` has
583 /// to be less than `10 * divisor`!
585 f: &mut fmt::Formatter,
586 mut integer_part: u64,
587 mut fractional_part: u32,
590 // Encode the fractional part into a temporary buffer. The buffer
591 // only need to hold 9 elements, because `fractional_part` has to
592 // be smaller than 10^9. The buffer is prefilled with '0' digits
593 // to simplify the code below.
594 let mut buf = [b'0'; 9];
596 // The next digit is written at this position
599 // We keep writing digits into the buffer while there are non-zero
600 // digits left and we haven't written enough digits yet.
601 while fractional_part > 0 && pos < f.precision().unwrap_or(9) {
602 // Write new digit into the buffer
603 buf[pos] = b'0' + (fractional_part / divisor) as u8;
605 fractional_part %= divisor;
610 // If a precision < 9 was specified, there may be some non-zero
611 // digits left that weren't written into the buffer. In that case we
612 // need to perform rounding to match the semantics of printing
613 // normal floating point numbers. However, we only need to do work
614 // when rounding up. This happens if the first digit of the
615 // remaining ones is >= 5.
616 if fractional_part > 0 && fractional_part >= divisor * 5 {
617 // Round up the number contained in the buffer. We go through
618 // the buffer backwards and keep track of the carry.
619 let mut rev_pos = pos;
620 let mut carry = true;
621 while carry && rev_pos > 0 {
624 // If the digit in the buffer is not '9', we just need to
625 // increment it and can stop then (since we don't have a
626 // carry anymore). Otherwise, we set it to '0' (overflow)
628 if buf[rev_pos] < b'9' {
636 // If we still have the carry bit set, that means that we set
637 // the whole buffer to '0's and need to increment the integer
644 // Determine the end of the buffer: if precision is set, we just
645 // use as many digits from the buffer (capped to 9). If it isn't
646 // set, we only use all digits up to the last non-zero one.
647 let end = f.precision().map(|p| ::cmp::min(p, 9)).unwrap_or(pos);
649 // If we haven't emitted a single fractional digit and the precision
650 // wasn't set to a non-zero value, we don't print the decimal point.
652 write!(f, "{}", integer_part)
654 // We are only writing ASCII digits into the buffer and it was
655 // initialized with '0's, so it contains valid UTF8.
657 ::str::from_utf8_unchecked(&buf[..end])
660 // If the user request a precision > 9, we pad '0's at the end.
661 let w = f.precision().unwrap_or(pos);
662 write!(f, "{}.{:0<width$}", integer_part, s, width = w)
666 // Print leading '+' sign if requested
672 fmt_decimal(f, self.secs, self.nanos, 100_000_000)?;
674 } else if self.nanos >= 1_000_000 {
675 fmt_decimal(f, self.nanos as u64 / 1_000_000, self.nanos % 1_000_000, 100_000)?;
677 } else if self.nanos >= 1_000 {
678 fmt_decimal(f, self.nanos as u64 / 1_000, self.nanos % 1_000, 100)?;
681 fmt_decimal(f, self.nanos as u64, 0, 1)?;