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));
25 use ops::{Add, Sub, Mul, Div, AddAssign, SubAssign, MulAssign, DivAssign};
27 const NANOS_PER_SEC: u32 = 1_000_000_000;
28 const NANOS_PER_MILLI: u32 = 1_000_000;
29 const NANOS_PER_MICRO: u32 = 1_000;
30 const MILLIS_PER_SEC: u64 = 1_000;
31 const MICROS_PER_SEC: u64 = 1_000_000;
33 /// A `Duration` type to represent a span of time, typically used for system
36 /// Each `Duration` is composed of a whole number of seconds and a fractional part
37 /// represented in nanoseconds. If the underlying system does not support
38 /// nanosecond-level precision, APIs binding a system timeout will typically round up
39 /// the number of nanoseconds.
41 /// `Duration`s implement many common traits, including [`Add`], [`Sub`], and other
44 /// [`Add`]: ../../std/ops/trait.Add.html
45 /// [`Sub`]: ../../std/ops/trait.Sub.html
46 /// [`ops`]: ../../std/ops/index.html
51 /// use std::time::Duration;
53 /// let five_seconds = Duration::new(5, 0);
54 /// let five_seconds_and_five_nanos = five_seconds + Duration::new(0, 5);
56 /// assert_eq!(five_seconds_and_five_nanos.as_secs(), 5);
57 /// assert_eq!(five_seconds_and_five_nanos.subsec_nanos(), 5);
59 /// let ten_millis = Duration::from_millis(10);
61 #[stable(feature = "duration", since = "1.3.0")]
62 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash, Default)]
65 nanos: u32, // Always 0 <= nanos < NANOS_PER_SEC
69 /// Creates a new `Duration` from the specified number of whole seconds and
70 /// additional nanoseconds.
72 /// If the number of nanoseconds is greater than 1 billion (the number of
73 /// nanoseconds in a second), then it will carry over into the seconds provided.
77 /// This constructor will panic if the carry from the nanoseconds overflows
78 /// the seconds counter.
83 /// use std::time::Duration;
85 /// let five_seconds = Duration::new(5, 0);
87 #[stable(feature = "duration", since = "1.3.0")]
89 pub fn new(secs: u64, nanos: u32) -> Duration {
90 let secs = secs.checked_add((nanos / NANOS_PER_SEC) as u64)
91 .expect("overflow in Duration::new");
92 let nanos = nanos % NANOS_PER_SEC;
93 Duration { secs: secs, nanos: nanos }
96 /// Creates a new `Duration` from the specified number of whole seconds.
101 /// use std::time::Duration;
103 /// let duration = Duration::from_secs(5);
105 /// assert_eq!(5, duration.as_secs());
106 /// assert_eq!(0, duration.subsec_nanos());
108 #[stable(feature = "duration", since = "1.3.0")]
110 pub const fn from_secs(secs: u64) -> Duration {
111 Duration { secs: secs, nanos: 0 }
114 /// Creates a new `Duration` from the specified number of milliseconds.
119 /// use std::time::Duration;
121 /// let duration = Duration::from_millis(2569);
123 /// assert_eq!(2, duration.as_secs());
124 /// assert_eq!(569_000_000, duration.subsec_nanos());
126 #[stable(feature = "duration", since = "1.3.0")]
128 pub const fn from_millis(millis: u64) -> Duration {
130 secs: millis / MILLIS_PER_SEC,
131 nanos: ((millis % MILLIS_PER_SEC) as u32) * NANOS_PER_MILLI,
135 /// Creates a new `Duration` from the specified number of microseconds.
140 /// use std::time::Duration;
142 /// let duration = Duration::from_micros(1_000_002);
144 /// assert_eq!(1, duration.as_secs());
145 /// assert_eq!(2000, duration.subsec_nanos());
147 #[stable(feature = "duration_from_micros", since = "1.27.0")]
149 pub const fn from_micros(micros: u64) -> Duration {
151 secs: micros / MICROS_PER_SEC,
152 nanos: ((micros % MICROS_PER_SEC) as u32) * NANOS_PER_MICRO,
156 /// Creates a new `Duration` from the specified number of nanoseconds.
161 /// use std::time::Duration;
163 /// let duration = Duration::from_nanos(1_000_000_123);
165 /// assert_eq!(1, duration.as_secs());
166 /// assert_eq!(123, duration.subsec_nanos());
168 #[stable(feature = "duration_extras", since = "1.27.0")]
170 pub const fn from_nanos(nanos: u64) -> Duration {
172 secs: nanos / (NANOS_PER_SEC as u64),
173 nanos: (nanos % (NANOS_PER_SEC as u64)) as u32,
177 /// Returns the number of _whole_ seconds contained by this `Duration`.
179 /// The returned value does not include the fractional (nanosecond) part of the
180 /// duration, which can be obtained using [`subsec_nanos`].
185 /// use std::time::Duration;
187 /// let duration = Duration::new(5, 730023852);
188 /// assert_eq!(duration.as_secs(), 5);
191 /// To determine the total number of seconds represented by the `Duration`,
192 /// use `as_secs` in combination with [`subsec_nanos`]:
195 /// use std::time::Duration;
197 /// let duration = Duration::new(5, 730023852);
199 /// assert_eq!(5.730023852,
200 /// duration.as_secs() as f64
201 /// + duration.subsec_nanos() as f64 * 1e-9);
204 /// [`subsec_nanos`]: #method.subsec_nanos
205 #[stable(feature = "duration", since = "1.3.0")]
207 pub fn as_secs(&self) -> u64 { self.secs }
209 /// Returns the fractional part of this `Duration`, in milliseconds.
211 /// This method does **not** return the length of the duration when
212 /// represented by milliseconds. The returned number always represents a
213 /// fractional portion of a second (i.e. it is less than one thousand).
218 /// use std::time::Duration;
220 /// let duration = Duration::from_millis(5432);
221 /// assert_eq!(duration.as_secs(), 5);
222 /// assert_eq!(duration.subsec_millis(), 432);
224 #[stable(feature = "duration_extras", since = "1.27.0")]
226 pub fn subsec_millis(&self) -> u32 { self.nanos / NANOS_PER_MILLI }
228 /// Returns the fractional part of this `Duration`, in microseconds.
230 /// This method does **not** return the length of the duration when
231 /// represented by microseconds. The returned number always represents a
232 /// fractional portion of a second (i.e. it is less than one million).
237 /// use std::time::Duration;
239 /// let duration = Duration::from_micros(1_234_567);
240 /// assert_eq!(duration.as_secs(), 1);
241 /// assert_eq!(duration.subsec_micros(), 234_567);
243 #[stable(feature = "duration_extras", since = "1.27.0")]
245 pub fn subsec_micros(&self) -> u32 { self.nanos / NANOS_PER_MICRO }
247 /// Returns the fractional part of this `Duration`, in nanoseconds.
249 /// This method does **not** return the length of the duration when
250 /// represented by nanoseconds. The returned number always represents a
251 /// fractional portion of a second (i.e. it is less than one billion).
256 /// use std::time::Duration;
258 /// let duration = Duration::from_millis(5010);
259 /// assert_eq!(duration.as_secs(), 5);
260 /// assert_eq!(duration.subsec_nanos(), 10_000_000);
262 #[stable(feature = "duration", since = "1.3.0")]
264 pub fn subsec_nanos(&self) -> u32 { self.nanos }
266 /// Checked `Duration` addition. Computes `self + other`, returning [`None`]
267 /// if overflow occurred.
269 /// [`None`]: ../../std/option/enum.Option.html#variant.None
276 /// use std::time::Duration;
278 /// assert_eq!(Duration::new(0, 0).checked_add(Duration::new(0, 1)), Some(Duration::new(0, 1)));
279 /// assert_eq!(Duration::new(1, 0).checked_add(Duration::new(std::u64::MAX, 0)), None);
281 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
283 pub fn checked_add(self, rhs: Duration) -> Option<Duration> {
284 if let Some(mut secs) = self.secs.checked_add(rhs.secs) {
285 let mut nanos = self.nanos + rhs.nanos;
286 if nanos >= NANOS_PER_SEC {
287 nanos -= NANOS_PER_SEC;
288 if let Some(new_secs) = secs.checked_add(1) {
294 debug_assert!(nanos < NANOS_PER_SEC);
304 /// Checked `Duration` subtraction. Computes `self - other`, returning [`None`]
305 /// if the result would be negative or if overflow occurred.
307 /// [`None`]: ../../std/option/enum.Option.html#variant.None
314 /// use std::time::Duration;
316 /// assert_eq!(Duration::new(0, 1).checked_sub(Duration::new(0, 0)), Some(Duration::new(0, 1)));
317 /// assert_eq!(Duration::new(0, 0).checked_sub(Duration::new(0, 1)), None);
319 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
321 pub fn checked_sub(self, rhs: Duration) -> Option<Duration> {
322 if let Some(mut secs) = self.secs.checked_sub(rhs.secs) {
323 let nanos = if self.nanos >= rhs.nanos {
324 self.nanos - rhs.nanos
326 if let Some(sub_secs) = secs.checked_sub(1) {
328 self.nanos + NANOS_PER_SEC - rhs.nanos
333 debug_assert!(nanos < NANOS_PER_SEC);
334 Some(Duration { secs: secs, nanos: nanos })
340 /// Checked `Duration` multiplication. Computes `self * other`, returning
341 /// [`None`] if overflow occurred.
343 /// [`None`]: ../../std/option/enum.Option.html#variant.None
350 /// use std::time::Duration;
352 /// assert_eq!(Duration::new(0, 500_000_001).checked_mul(2), Some(Duration::new(1, 2)));
353 /// assert_eq!(Duration::new(std::u64::MAX - 1, 0).checked_mul(2), None);
355 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
357 pub fn checked_mul(self, rhs: u32) -> Option<Duration> {
358 // Multiply nanoseconds as u64, because it cannot overflow that way.
359 let total_nanos = self.nanos as u64 * rhs as u64;
360 let extra_secs = total_nanos / (NANOS_PER_SEC as u64);
361 let nanos = (total_nanos % (NANOS_PER_SEC as u64)) as u32;
362 if let Some(secs) = self.secs
363 .checked_mul(rhs as u64)
364 .and_then(|s| s.checked_add(extra_secs)) {
365 debug_assert!(nanos < NANOS_PER_SEC);
375 /// Checked `Duration` division. Computes `self / other`, returning [`None`]
378 /// [`None`]: ../../std/option/enum.Option.html#variant.None
385 /// use std::time::Duration;
387 /// assert_eq!(Duration::new(2, 0).checked_div(2), Some(Duration::new(1, 0)));
388 /// assert_eq!(Duration::new(1, 0).checked_div(2), Some(Duration::new(0, 500_000_000)));
389 /// assert_eq!(Duration::new(2, 0).checked_div(0), None);
391 #[stable(feature = "duration_checked_ops", since = "1.16.0")]
393 pub fn checked_div(self, rhs: u32) -> Option<Duration> {
395 let secs = self.secs / (rhs as u64);
396 let carry = self.secs - secs * (rhs as u64);
397 let extra_nanos = carry * (NANOS_PER_SEC as u64) / (rhs as u64);
398 let nanos = self.nanos / rhs + (extra_nanos as u32);
399 debug_assert!(nanos < NANOS_PER_SEC);
400 Some(Duration { secs: secs, nanos: nanos })
407 #[stable(feature = "duration", since = "1.3.0")]
408 impl Add for Duration {
409 type Output = Duration;
411 fn add(self, rhs: Duration) -> Duration {
412 self.checked_add(rhs).expect("overflow when adding durations")
416 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
417 impl AddAssign for Duration {
418 fn add_assign(&mut self, rhs: Duration) {
423 #[stable(feature = "duration", since = "1.3.0")]
424 impl Sub for Duration {
425 type Output = Duration;
427 fn sub(self, rhs: Duration) -> Duration {
428 self.checked_sub(rhs).expect("overflow when subtracting durations")
432 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
433 impl SubAssign for Duration {
434 fn sub_assign(&mut self, rhs: Duration) {
439 #[stable(feature = "duration", since = "1.3.0")]
440 impl Mul<u32> for Duration {
441 type Output = Duration;
443 fn mul(self, rhs: u32) -> Duration {
444 self.checked_mul(rhs).expect("overflow when multiplying duration by scalar")
448 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
449 impl MulAssign<u32> for Duration {
450 fn mul_assign(&mut self, rhs: u32) {
455 #[stable(feature = "duration", since = "1.3.0")]
456 impl Div<u32> for Duration {
457 type Output = Duration;
459 fn div(self, rhs: u32) -> Duration {
460 self.checked_div(rhs).expect("divide by zero error when dividing duration by scalar")
464 #[stable(feature = "time_augmented_assignment", since = "1.9.0")]
465 impl DivAssign<u32> for Duration {
466 fn div_assign(&mut self, rhs: u32) {
471 #[stable(feature = "duration_sum", since = "1.16.0")]
472 impl Sum for Duration {
473 fn sum<I: Iterator<Item=Duration>>(iter: I) -> Duration {
474 iter.fold(Duration::new(0, 0), |a, b| a + b)
478 #[stable(feature = "duration_sum", since = "1.16.0")]
479 impl<'a> Sum<&'a Duration> for Duration {
480 fn sum<I: Iterator<Item=&'a Duration>>(iter: I) -> Duration {
481 iter.fold(Duration::new(0, 0), |a, b| a + *b)