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rust/rust/84f09c7144fc419fc42915b406db8e53ab2eca03/./library/core/src/time.rs
blob: c123c66ee3bc05e8ce0886f79770cfc5b2880009 [file]
#![stable(feature = "duration_core", since = "1.25.0")]
//! Temporal quantification.
//!
//! # Examples:
//!
//! There are multiple ways to create a new [`Duration`]:
//!
//! ```
//! # use std::time::Duration;
//! let five_seconds = Duration::from_secs(5);
//! assert_eq!(five_seconds, Duration::from_millis(5_000));
//! assert_eq!(five_seconds, Duration::from_micros(5_000_000));
//! assert_eq!(five_seconds, Duration::from_nanos(5_000_000_000));
//!
//! let ten_seconds = Duration::from_secs(10);
//! let seven_nanos = Duration::from_nanos(7);
//! let total = ten_seconds + seven_nanos;
//! assert_eq!(total, Duration::new(10, 7));
//! ```
use crate::fmt;
use crate::iter::Sum;
use crate::num::niche_types::Nanoseconds;
use crate::ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign};
const NANOS_PER_SEC: u32 = 1_000_000_000;
const NANOS_PER_MILLI: u32 = 1_000_000;
const NANOS_PER_MICRO: u32 = 1_000;
const MILLIS_PER_SEC: u64 = 1_000;
const MICROS_PER_SEC: u64 = 1_000_000;
#[unstable(feature = "duration_units", issue = "120301")]
const SECS_PER_MINUTE: u64 = 60;
#[unstable(feature = "duration_units", issue = "120301")]
const MINS_PER_HOUR: u64 = 60;
#[unstable(feature = "duration_units", issue = "120301")]
const HOURS_PER_DAY: u64 = 24;
#[unstable(feature = "duration_units", issue = "120301")]
const DAYS_PER_WEEK: u64 = 7;
/// A `Duration` type to represent a span of time, typically used for system
/// timeouts.
///
/// Each `Duration` is composed of a whole number of seconds and a fractional part
/// represented in nanoseconds. If the underlying system does not support
/// nanosecond-level precision, APIs binding a system timeout will typically round up
/// the number of nanoseconds.
///
/// [`Duration`]s implement many common traits, including [`Add`], [`Sub`], and other
/// [`ops`] traits. It implements [`Default`] by returning a zero-length `Duration`.
///
/// [`ops`]: crate::ops
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let five_seconds = Duration::new(5, 0);
/// let five_seconds_and_five_nanos = five_seconds + Duration::new(0, 5);
///
/// assert_eq!(five_seconds_and_five_nanos.as_secs(), 5);
/// assert_eq!(five_seconds_and_five_nanos.subsec_nanos(), 5);
///
/// let ten_millis = Duration::from_millis(10);
/// ```
///
/// # Formatting `Duration` values
///
/// `Duration` intentionally does not have a `Display` impl, as there are a
/// variety of ways to format spans of time for human readability. `Duration`
/// provides a `Debug` impl that shows the full precision of the value.
///
/// The `Debug` output uses the non-ASCII "µs" suffix for microseconds. If your
/// program output may appear in contexts that cannot rely on full Unicode
/// compatibility, you may wish to format `Duration` objects yourself or use a
/// crate to do so.
#[stable(feature = "duration", since = "1.3.0")]
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
#[rustc_diagnostic_item = "Duration"]
pub struct Duration {
secs: u64,
nanos: Nanoseconds, // Always 0 <= nanos < NANOS_PER_SEC
}
impl Duration {
/// The duration of one second.
///
/// # Examples
///
/// ```
/// #![feature(duration_constants)]
/// use std::time::Duration;
///
/// assert_eq!(Duration::SECOND, Duration::from_secs(1));
/// ```
#[unstable(feature = "duration_constants", issue = "57391")]
pub const SECOND: Duration = Duration::from_secs(1);
/// The duration of one millisecond.
///
/// # Examples
///
/// ```
/// #![feature(duration_constants)]
/// use std::time::Duration;
///
/// assert_eq!(Duration::MILLISECOND, Duration::from_millis(1));
/// ```
#[unstable(feature = "duration_constants", issue = "57391")]
pub const MILLISECOND: Duration = Duration::from_millis(1);
/// The duration of one microsecond.
///
/// # Examples
///
/// ```
/// #![feature(duration_constants)]
/// use std::time::Duration;
///
/// assert_eq!(Duration::MICROSECOND, Duration::from_micros(1));
/// ```
#[unstable(feature = "duration_constants", issue = "57391")]
pub const MICROSECOND: Duration = Duration::from_micros(1);
/// The duration of one nanosecond.
///
/// # Examples
///
/// ```
/// #![feature(duration_constants)]
/// use std::time::Duration;
///
/// assert_eq!(Duration::NANOSECOND, Duration::from_nanos(1));
/// ```
#[unstable(feature = "duration_constants", issue = "57391")]
pub const NANOSECOND: Duration = Duration::from_nanos(1);
/// A duration of zero time.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::ZERO;
/// assert!(duration.is_zero());
/// assert_eq!(duration.as_nanos(), 0);
/// ```
#[stable(feature = "duration_zero", since = "1.53.0")]
pub const ZERO: Duration = Duration::from_nanos(0);
/// The maximum duration.
///
/// May vary by platform as necessary. Must be able to contain the difference between
/// two instances of [`Instant`] or two instances of [`SystemTime`].
/// This constraint gives it a value of about 584,942,417,355 years in practice,
/// which is currently used on all platforms.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::MAX, Duration::new(u64::MAX, 1_000_000_000 - 1));
/// ```
/// [`Instant`]: ../../std/time/struct.Instant.html
/// [`SystemTime`]: ../../std/time/struct.SystemTime.html
#[stable(feature = "duration_saturating_ops", since = "1.53.0")]
pub const MAX: Duration = Duration::new(u64::MAX, NANOS_PER_SEC - 1);
/// Creates a new `Duration` from the specified number of whole seconds and
/// additional nanoseconds.
///
/// If the number of nanoseconds is greater than 1 billion (the number of
/// nanoseconds in a second), then it will carry over into the seconds provided.
///
/// # Panics
///
/// This constructor will panic if the carry from the nanoseconds overflows
/// the seconds counter.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let five_seconds = Duration::new(5, 0);
/// ```
#[stable(feature = "duration", since = "1.3.0")]
#[inline]
#[must_use]
#[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
pub const fn new(secs: u64, nanos: u32) -> Duration {
if nanos < NANOS_PER_SEC {
// SAFETY: nanos < NANOS_PER_SEC, therefore nanos is within the valid range
Duration { secs, nanos: unsafe { Nanoseconds::new_unchecked(nanos) } }
} else {
let secs = secs
.checked_add((nanos / NANOS_PER_SEC) as u64)
.expect("overflow in Duration::new");
let nanos = nanos % NANOS_PER_SEC;
// SAFETY: nanos % NANOS_PER_SEC < NANOS_PER_SEC, therefore nanos is within the valid range
Duration { secs, nanos: unsafe { Nanoseconds::new_unchecked(nanos) } }
}
}
/// Creates a new `Duration` from the specified number of whole seconds.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_secs(5);
///
/// assert_eq!(5, duration.as_secs());
/// assert_eq!(0, duration.subsec_nanos());
/// ```
#[stable(feature = "duration", since = "1.3.0")]
#[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
pub const fn from_secs(secs: u64) -> Duration {
Duration { secs, nanos: Nanoseconds::ZERO }
}
/// Creates a new `Duration` from the specified number of milliseconds.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_millis(2_569);
///
/// assert_eq!(2, duration.as_secs());
/// assert_eq!(569_000_000, duration.subsec_nanos());
/// ```
#[stable(feature = "duration", since = "1.3.0")]
#[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
pub const fn from_millis(millis: u64) -> Duration {
let secs = millis / MILLIS_PER_SEC;
let subsec_millis = (millis % MILLIS_PER_SEC) as u32;
// SAFETY: (x % 1_000) * 1_000_000 < 1_000_000_000
// => x % 1_000 < 1_000
let subsec_nanos = unsafe { Nanoseconds::new_unchecked(subsec_millis * NANOS_PER_MILLI) };
Duration { secs, nanos: subsec_nanos }
}
/// Creates a new `Duration` from the specified number of microseconds.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_micros(1_000_002);
///
/// assert_eq!(1, duration.as_secs());
/// assert_eq!(2_000, duration.subsec_nanos());
/// ```
#[stable(feature = "duration_from_micros", since = "1.27.0")]
#[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
pub const fn from_micros(micros: u64) -> Duration {
let secs = micros / MICROS_PER_SEC;
let subsec_micros = (micros % MICROS_PER_SEC) as u32;
// SAFETY: (x % 1_000_000) * 1_000 < 1_000_000_000
// => x % 1_000_000 < 1_000_000
let subsec_nanos = unsafe { Nanoseconds::new_unchecked(subsec_micros * NANOS_PER_MICRO) };
Duration { secs, nanos: subsec_nanos }
}
/// Creates a new `Duration` from the specified number of nanoseconds.
///
/// Note: Using this on the return value of `as_nanos()` might cause unexpected behavior:
/// `as_nanos()` returns a u128, and can return values that do not fit in u64, e.g. 585 years.
/// Instead, consider using the pattern `Duration::new(d.as_secs(), d.subsec_nanos())`
/// if you cannot copy/clone the Duration directly.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_nanos(1_000_000_123);
///
/// assert_eq!(1, duration.as_secs());
/// assert_eq!(123, duration.subsec_nanos());
/// ```
#[stable(feature = "duration_extras", since = "1.27.0")]
#[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
pub const fn from_nanos(nanos: u64) -> Duration {
const NANOS_PER_SEC: u64 = self::NANOS_PER_SEC as u64;
let secs = nanos / NANOS_PER_SEC;
let subsec_nanos = (nanos % NANOS_PER_SEC) as u32;
// SAFETY: x % 1_000_000_000 < 1_000_000_000
let subsec_nanos = unsafe { Nanoseconds::new_unchecked(subsec_nanos) };
Duration { secs, nanos: subsec_nanos }
}
/// Creates a new `Duration` from the specified number of nanoseconds.
///
/// # Panics
///
/// Panics if the given number of nanoseconds is greater than [`Duration::MAX`].
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let nanos = 10_u128.pow(24) + 321;
/// let duration = Duration::from_nanos_u128(nanos);
///
/// assert_eq!(10_u64.pow(15), duration.as_secs());
/// assert_eq!(321, duration.subsec_nanos());
/// ```
#[stable(feature = "duration_from_nanos_u128", since = "1.93.0")]
#[rustc_const_stable(feature = "duration_from_nanos_u128", since = "1.93.0")]
#[must_use]
#[inline]
#[track_caller]
#[rustc_allow_const_fn_unstable(const_trait_impl, const_convert)] // for `u64::try_from`
pub const fn from_nanos_u128(nanos: u128) -> Duration {
const NANOS_PER_SEC: u128 = self::NANOS_PER_SEC as u128;
let Ok(secs) = u64::try_from(nanos / NANOS_PER_SEC) else {
panic!("overflow in `Duration::from_nanos_u128`");
};
let subsec_nanos = (nanos % NANOS_PER_SEC) as u32;
// SAFETY: x % 1_000_000_000 < 1_000_000_000 also, subsec_nanos >= 0 since u128 >=0 and u32 >=0
let subsec_nanos = unsafe { Nanoseconds::new_unchecked(subsec_nanos) };
Duration { secs: secs as u64, nanos: subsec_nanos }
}
/// Creates a new `Duration` from the specified number of weeks.
///
/// For this function, one week is defined as 7 days, or 604,800 seconds.
///
/// # Panics
///
/// Panics if the given number of weeks overflows the `Duration` size.
///
/// # Examples
///
/// ```
/// #![feature(duration_constructors)]
/// use std::time::Duration;
///
/// let duration = Duration::from_weeks(4);
///
/// assert_eq!(4 * 7 * 24 * 60 * 60, duration.as_secs());
/// assert_eq!(0, duration.subsec_nanos());
/// ```
#[unstable(feature = "duration_constructors", issue = "120301")]
#[must_use]
#[inline]
pub const fn from_weeks(weeks: u64) -> Duration {
if weeks > u64::MAX / (SECS_PER_MINUTE * MINS_PER_HOUR * HOURS_PER_DAY * DAYS_PER_WEEK) {
panic!("overflow in Duration::from_weeks");
}
Duration::from_secs(weeks * MINS_PER_HOUR * SECS_PER_MINUTE * HOURS_PER_DAY * DAYS_PER_WEEK)
}
/// Creates a new `Duration` from the specified number of days.
///
/// For this function, one day is defined as 24 hours, or 86,400 seconds.
///
/// # Panics
///
/// Panics if the given number of days overflows the `Duration` size.
///
/// # Examples
///
/// ```
/// #![feature(duration_constructors)]
/// use std::time::Duration;
///
/// let duration = Duration::from_days(7);
///
/// assert_eq!(7 * 24 * 60 * 60, duration.as_secs());
/// assert_eq!(0, duration.subsec_nanos());
/// ```
#[unstable(feature = "duration_constructors", issue = "120301")]
#[must_use]
#[inline]
pub const fn from_days(days: u64) -> Duration {
if days > u64::MAX / (SECS_PER_MINUTE * MINS_PER_HOUR * HOURS_PER_DAY) {
panic!("overflow in Duration::from_days");
}
Duration::from_secs(days * MINS_PER_HOUR * SECS_PER_MINUTE * HOURS_PER_DAY)
}
/// Creates a new `Duration` from the specified number of hours.
///
/// For this function, one hour is defined as 60 minutes, or 3,600 seconds.
///
/// # Panics
///
/// Panics if the given number of hours overflows the `Duration` size.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_hours(6);
///
/// assert_eq!(6 * 60 * 60, duration.as_secs());
/// assert_eq!(0, duration.subsec_nanos());
/// ```
#[stable(feature = "duration_constructors_lite", since = "1.91.0")]
#[rustc_const_stable(feature = "duration_constructors_lite", since = "1.91.0")]
#[must_use]
#[inline]
pub const fn from_hours(hours: u64) -> Duration {
if hours > u64::MAX / (SECS_PER_MINUTE * MINS_PER_HOUR) {
panic!("overflow in Duration::from_hours");
}
Duration::from_secs(hours * MINS_PER_HOUR * SECS_PER_MINUTE)
}
/// Creates a new `Duration` from the specified number of minutes.
///
/// For this function, one minute is defined as 60 seconds.
///
/// # Panics
///
/// Panics if the given number of minutes overflows the `Duration` size.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_mins(10);
///
/// assert_eq!(10 * 60, duration.as_secs());
/// assert_eq!(0, duration.subsec_nanos());
/// ```
#[stable(feature = "duration_constructors_lite", since = "1.91.0")]
#[rustc_const_stable(feature = "duration_constructors_lite", since = "1.91.0")]
#[must_use]
#[inline]
pub const fn from_mins(mins: u64) -> Duration {
if mins > u64::MAX / SECS_PER_MINUTE {
panic!("overflow in Duration::from_mins");
}
Duration::from_secs(mins * SECS_PER_MINUTE)
}
/// Returns true if this `Duration` spans no time.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert!(Duration::ZERO.is_zero());
/// assert!(Duration::new(0, 0).is_zero());
/// assert!(Duration::from_nanos(0).is_zero());
/// assert!(Duration::from_secs(0).is_zero());
///
/// assert!(!Duration::new(1, 1).is_zero());
/// assert!(!Duration::from_nanos(1).is_zero());
/// assert!(!Duration::from_secs(1).is_zero());
/// ```
#[must_use]
#[stable(feature = "duration_zero", since = "1.53.0")]
#[rustc_const_stable(feature = "duration_zero", since = "1.53.0")]
#[inline]
pub const fn is_zero(&self) -> bool {
self.secs == 0 && self.nanos.as_inner() == 0
}
/// Returns the number of _whole_ seconds contained by this `Duration`.
///
/// The returned value does not include the fractional (nanosecond) part of the
/// duration, which can be obtained using [`subsec_nanos`].
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::new(5, 730_023_852);
/// assert_eq!(duration.as_secs(), 5);
/// ```
///
/// To determine the total number of seconds represented by the `Duration`
/// including the fractional part, use [`as_secs_f64`] or [`as_secs_f32`]
///
/// [`as_secs_f64`]: Duration::as_secs_f64
/// [`as_secs_f32`]: Duration::as_secs_f32
/// [`subsec_nanos`]: Duration::subsec_nanos
#[stable(feature = "duration", since = "1.3.0")]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
#[must_use]
#[inline]
pub const fn as_secs(&self) -> u64 {
self.secs
}
/// Returns the fractional part of this `Duration`, in whole milliseconds.
///
/// This method does **not** return the length of the duration when
/// represented by milliseconds. The returned number always represents a
/// fractional portion of a second (i.e., it is less than one thousand).
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_millis(5_432);
/// assert_eq!(duration.as_secs(), 5);
/// assert_eq!(duration.subsec_millis(), 432);
/// ```
#[stable(feature = "duration_extras", since = "1.27.0")]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
#[must_use]
#[inline]
pub const fn subsec_millis(&self) -> u32 {
self.nanos.as_inner() / NANOS_PER_MILLI
}
/// Returns the fractional part of this `Duration`, in whole microseconds.
///
/// This method does **not** return the length of the duration when
/// represented by microseconds. The returned number always represents a
/// fractional portion of a second (i.e., it is less than one million).
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_micros(1_234_567);
/// assert_eq!(duration.as_secs(), 1);
/// assert_eq!(duration.subsec_micros(), 234_567);
/// ```
#[stable(feature = "duration_extras", since = "1.27.0")]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
#[must_use]
#[inline]
pub const fn subsec_micros(&self) -> u32 {
self.nanos.as_inner() / NANOS_PER_MICRO
}
/// Returns the fractional part of this `Duration`, in nanoseconds.
///
/// This method does **not** return the length of the duration when
/// represented by nanoseconds. The returned number always represents a
/// fractional portion of a second (i.e., it is less than one billion).
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::from_millis(5_010);
/// assert_eq!(duration.as_secs(), 5);
/// assert_eq!(duration.subsec_nanos(), 10_000_000);
/// ```
#[stable(feature = "duration", since = "1.3.0")]
#[rustc_const_stable(feature = "duration_consts", since = "1.32.0")]
#[must_use]
#[inline]
pub const fn subsec_nanos(&self) -> u32 {
self.nanos.as_inner()
}
/// Returns the total number of whole milliseconds contained by this `Duration`.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::new(5, 730_023_852);
/// assert_eq!(duration.as_millis(), 5_730);
/// ```
#[stable(feature = "duration_as_u128", since = "1.33.0")]
#[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
#[must_use]
#[inline]
pub const fn as_millis(&self) -> u128 {
self.secs as u128 * MILLIS_PER_SEC as u128
+ (self.nanos.as_inner() / NANOS_PER_MILLI) as u128
}
/// Returns the total number of whole microseconds contained by this `Duration`.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::new(5, 730_023_852);
/// assert_eq!(duration.as_micros(), 5_730_023);
/// ```
#[stable(feature = "duration_as_u128", since = "1.33.0")]
#[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
#[must_use]
#[inline]
pub const fn as_micros(&self) -> u128 {
self.secs as u128 * MICROS_PER_SEC as u128
+ (self.nanos.as_inner() / NANOS_PER_MICRO) as u128
}
/// Returns the total number of nanoseconds contained by this `Duration`.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let duration = Duration::new(5, 730_023_852);
/// assert_eq!(duration.as_nanos(), 5_730_023_852);
/// ```
#[stable(feature = "duration_as_u128", since = "1.33.0")]
#[rustc_const_stable(feature = "duration_as_u128", since = "1.33.0")]
#[must_use]
#[inline]
pub const fn as_nanos(&self) -> u128 {
self.secs as u128 * NANOS_PER_SEC as u128 + self.nanos.as_inner() as u128
}
/// Computes the absolute difference between `self` and `other`.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::new(100, 0).abs_diff(Duration::new(80, 0)), Duration::new(20, 0));
/// assert_eq!(Duration::new(100, 400_000_000).abs_diff(Duration::new(110, 0)), Duration::new(9, 600_000_000));
/// ```
#[stable(feature = "duration_abs_diff", since = "1.81.0")]
#[rustc_const_stable(feature = "duration_abs_diff", since = "1.81.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn abs_diff(self, other: Duration) -> Duration {
if let Some(res) = self.checked_sub(other) { res } else { other.checked_sub(self).unwrap() }
}
/// Checked `Duration` addition. Computes `self + other`, returning [`None`]
/// if overflow occurred.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::new(0, 0).checked_add(Duration::new(0, 1)), Some(Duration::new(0, 1)));
/// assert_eq!(Duration::new(1, 0).checked_add(Duration::new(u64::MAX, 0)), None);
/// ```
#[stable(feature = "duration_checked_ops", since = "1.16.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
pub const fn checked_add(self, rhs: Duration) -> Option<Duration> {
if let Some(mut secs) = self.secs.checked_add(rhs.secs) {
let mut nanos = self.nanos.as_inner() + rhs.nanos.as_inner();
if nanos >= NANOS_PER_SEC {
nanos -= NANOS_PER_SEC;
let Some(new_secs) = secs.checked_add(1) else {
return None;
};
secs = new_secs;
}
debug_assert!(nanos < NANOS_PER_SEC);
Some(Duration::new(secs, nanos))
} else {
None
}
}
/// Saturating `Duration` addition. Computes `self + other`, returning [`Duration::MAX`]
/// if overflow occurred.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::new(0, 0).saturating_add(Duration::new(0, 1)), Duration::new(0, 1));
/// assert_eq!(Duration::new(1, 0).saturating_add(Duration::new(u64::MAX, 0)), Duration::MAX);
/// ```
#[stable(feature = "duration_saturating_ops", since = "1.53.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
pub const fn saturating_add(self, rhs: Duration) -> Duration {
match self.checked_add(rhs) {
Some(res) => res,
None => Duration::MAX,
}
}
/// Checked `Duration` subtraction. Computes `self - other`, returning [`None`]
/// if the result would be negative or if overflow occurred.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::new(0, 1).checked_sub(Duration::new(0, 0)), Some(Duration::new(0, 1)));
/// assert_eq!(Duration::new(0, 0).checked_sub(Duration::new(0, 1)), None);
/// ```
#[stable(feature = "duration_checked_ops", since = "1.16.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
pub const fn checked_sub(self, rhs: Duration) -> Option<Duration> {
if let Some(mut secs) = self.secs.checked_sub(rhs.secs) {
let nanos = if self.nanos.as_inner() >= rhs.nanos.as_inner() {
self.nanos.as_inner() - rhs.nanos.as_inner()
} else if let Some(sub_secs) = secs.checked_sub(1) {
secs = sub_secs;
self.nanos.as_inner() + NANOS_PER_SEC - rhs.nanos.as_inner()
} else {
return None;
};
debug_assert!(nanos < NANOS_PER_SEC);
Some(Duration::new(secs, nanos))
} else {
None
}
}
/// Saturating `Duration` subtraction. Computes `self - other`, returning [`Duration::ZERO`]
/// if the result would be negative or if overflow occurred.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::new(0, 1).saturating_sub(Duration::new(0, 0)), Duration::new(0, 1));
/// assert_eq!(Duration::new(0, 0).saturating_sub(Duration::new(0, 1)), Duration::ZERO);
/// ```
#[stable(feature = "duration_saturating_ops", since = "1.53.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
pub const fn saturating_sub(self, rhs: Duration) -> Duration {
match self.checked_sub(rhs) {
Some(res) => res,
None => Duration::ZERO,
}
}
/// Checked `Duration` multiplication. Computes `self * other`, returning
/// [`None`] if overflow occurred.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::new(0, 500_000_001).checked_mul(2), Some(Duration::new(1, 2)));
/// assert_eq!(Duration::new(u64::MAX - 1, 0).checked_mul(2), None);
/// ```
#[stable(feature = "duration_checked_ops", since = "1.16.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
pub const fn checked_mul(self, rhs: u32) -> Option<Duration> {
// Multiply nanoseconds as u64, because it cannot overflow that way.
let total_nanos = self.nanos.as_inner() as u64 * rhs as u64;
let extra_secs = total_nanos / (NANOS_PER_SEC as u64);
let nanos = (total_nanos % (NANOS_PER_SEC as u64)) as u32;
// FIXME(const-hack): use `and_then` once that is possible.
if let Some(s) = self.secs.checked_mul(rhs as u64) {
if let Some(secs) = s.checked_add(extra_secs) {
debug_assert!(nanos < NANOS_PER_SEC);
return Some(Duration::new(secs, nanos));
}
}
None
}
/// Saturating `Duration` multiplication. Computes `self * other`, returning
/// [`Duration::MAX`] if overflow occurred.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::new(0, 500_000_001).saturating_mul(2), Duration::new(1, 2));
/// assert_eq!(Duration::new(u64::MAX - 1, 0).saturating_mul(2), Duration::MAX);
/// ```
#[stable(feature = "duration_saturating_ops", since = "1.53.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
pub const fn saturating_mul(self, rhs: u32) -> Duration {
match self.checked_mul(rhs) {
Some(res) => res,
None => Duration::MAX,
}
}
/// Checked `Duration` division. Computes `self / other`, returning [`None`]
/// if `other == 0`.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// assert_eq!(Duration::new(2, 0).checked_div(2), Some(Duration::new(1, 0)));
/// assert_eq!(Duration::new(1, 0).checked_div(2), Some(Duration::new(0, 500_000_000)));
/// assert_eq!(Duration::new(2, 0).checked_div(0), None);
/// ```
#[stable(feature = "duration_checked_ops", since = "1.16.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_2", since = "1.58.0")]
pub const fn checked_div(self, rhs: u32) -> Option<Duration> {
if rhs != 0 {
let (secs, extra_secs) = (self.secs / (rhs as u64), self.secs % (rhs as u64));
let (mut nanos, extra_nanos) =
(self.nanos.as_inner() / rhs, self.nanos.as_inner() % rhs);
nanos +=
((extra_secs * (NANOS_PER_SEC as u64) + extra_nanos as u64) / (rhs as u64)) as u32;
debug_assert!(nanos < NANOS_PER_SEC);
Some(Duration::new(secs, nanos))
} else {
None
}
}
/// Returns the number of seconds contained by this `Duration` as `f64`.
///
/// The returned value includes the fractional (nanosecond) part of the duration.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 700_000_000);
/// assert_eq!(dur.as_secs_f64(), 2.7);
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
#[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts_float", since = "1.83.0")]
pub const fn as_secs_f64(&self) -> f64 {
(self.secs as f64) + (self.nanos.as_inner() as f64) / (NANOS_PER_SEC as f64)
}
/// Returns the number of seconds contained by this `Duration` as `f32`.
///
/// The returned value includes the fractional (nanosecond) part of the duration.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 700_000_000);
/// assert_eq!(dur.as_secs_f32(), 2.7);
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
#[must_use]
#[inline]
#[rustc_const_stable(feature = "duration_consts_float", since = "1.83.0")]
pub const fn as_secs_f32(&self) -> f32 {
(self.secs as f32) + (self.nanos.as_inner() as f32) / (NANOS_PER_SEC as f32)
}
/// Returns the number of milliseconds contained by this `Duration` as `f64`.
///
/// The returned value includes the fractional (nanosecond) part of the duration.
///
/// # Examples
/// ```
/// #![feature(duration_millis_float)]
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 345_678_000);
/// assert_eq!(dur.as_millis_f64(), 2_345.678);
/// ```
#[unstable(feature = "duration_millis_float", issue = "122451")]
#[must_use]
#[inline]
pub const fn as_millis_f64(&self) -> f64 {
(self.secs as f64) * (MILLIS_PER_SEC as f64)
+ (self.nanos.as_inner() as f64) / (NANOS_PER_MILLI as f64)
}
/// Returns the number of milliseconds contained by this `Duration` as `f32`.
///
/// The returned value includes the fractional (nanosecond) part of the duration.
///
/// # Examples
/// ```
/// #![feature(duration_millis_float)]
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 345_678_000);
/// assert_eq!(dur.as_millis_f32(), 2_345.678);
/// ```
#[unstable(feature = "duration_millis_float", issue = "122451")]
#[must_use]
#[inline]
pub const fn as_millis_f32(&self) -> f32 {
(self.secs as f32) * (MILLIS_PER_SEC as f32)
+ (self.nanos.as_inner() as f32) / (NANOS_PER_MILLI as f32)
}
/// Creates a new `Duration` from the specified number of seconds represented
/// as `f64`.
///
/// # Panics
/// This constructor will panic if `secs` is negative, overflows `Duration` or not finite.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let res = Duration::from_secs_f64(0.0);
/// assert_eq!(res, Duration::new(0, 0));
/// let res = Duration::from_secs_f64(1e-20);
/// assert_eq!(res, Duration::new(0, 0));
/// let res = Duration::from_secs_f64(4.2e-7);
/// assert_eq!(res, Duration::new(0, 420));
/// let res = Duration::from_secs_f64(2.7);
/// assert_eq!(res, Duration::new(2, 700_000_000));
/// let res = Duration::from_secs_f64(3e10);
/// assert_eq!(res, Duration::new(30_000_000_000, 0));
/// // subnormal float
/// let res = Duration::from_secs_f64(f64::from_bits(1));
/// assert_eq!(res, Duration::new(0, 0));
/// // conversion uses rounding
/// let res = Duration::from_secs_f64(0.999e-9);
/// assert_eq!(res, Duration::new(0, 1));
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
#[must_use]
#[inline]
pub fn from_secs_f64(secs: f64) -> Duration {
match Duration::try_from_secs_f64(secs) {
Ok(v) => v,
Err(e) => panic!("{e}"),
}
}
/// Creates a new `Duration` from the specified number of seconds represented
/// as `f32`.
///
/// # Panics
/// This constructor will panic if `secs` is negative, overflows `Duration` or not finite.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let res = Duration::from_secs_f32(0.0);
/// assert_eq!(res, Duration::new(0, 0));
/// let res = Duration::from_secs_f32(1e-20);
/// assert_eq!(res, Duration::new(0, 0));
/// let res = Duration::from_secs_f32(4.2e-7);
/// assert_eq!(res, Duration::new(0, 420));
/// let res = Duration::from_secs_f32(2.7);
/// assert_eq!(res, Duration::new(2, 700_000_048));
/// let res = Duration::from_secs_f32(3e10);
/// assert_eq!(res, Duration::new(30_000_001_024, 0));
/// // subnormal float
/// let res = Duration::from_secs_f32(f32::from_bits(1));
/// assert_eq!(res, Duration::new(0, 0));
/// // conversion uses rounding
/// let res = Duration::from_secs_f32(0.999e-9);
/// assert_eq!(res, Duration::new(0, 1));
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
#[must_use]
#[inline]
pub fn from_secs_f32(secs: f32) -> Duration {
match Duration::try_from_secs_f32(secs) {
Ok(v) => v,
Err(e) => panic!("{e}"),
}
}
/// Multiplies `Duration` by `f64`.
///
/// # Panics
/// This method will panic if result is negative, overflows `Duration` or not finite.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 700_000_000);
/// assert_eq!(dur.mul_f64(3.14), Duration::new(8, 478_000_000));
/// assert_eq!(dur.mul_f64(3.14e5), Duration::new(847_800, 0));
/// ```
///
/// Note that `f64` does not have enough bits ([`f64::MANTISSA_DIGITS`]) to represent the full
/// range of possible `Duration` with nanosecond precision, so rounding may occur even for
/// trivial operations like multiplying by 1.
///
/// ```
/// # #![feature(float_exact_integer_constants)]
/// use std::time::Duration;
///
/// // This is about 14.9 weeks, remaining precise to the nanosecond:
/// let weeks = Duration::from_nanos(f64::MAX_EXACT_INTEGER as u64);
/// assert_eq!(weeks, weeks.mul_f64(1.0));
///
/// // A larger value incurs rounding in the floating-point operation:
/// let weeks = Duration::from_nanos(u64::MAX);
/// assert_ne!(weeks, weeks.mul_f64(1.0));
///
/// // This is over 285 million years, remaining precise to the second:
/// let years = Duration::from_secs(f64::MAX_EXACT_INTEGER as u64);
/// assert_eq!(years, years.mul_f64(1.0));
///
/// // And again larger values incur rounding:
/// let years = Duration::from_secs(u64::MAX / 2);
/// assert_ne!(years, years.mul_f64(1.0));
/// ```
///
/// ```should_panic
/// # use std::time::Duration;
/// // In the extreme, rounding can even overflow `Duration`, which panics.
/// let _ = Duration::from_secs(u64::MAX).mul_f64(1.0);
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn mul_f64(self, rhs: f64) -> Duration {
Duration::from_secs_f64(rhs * self.as_secs_f64())
}
/// Multiplies `Duration` by `f32`.
///
/// Since the significand of `f32` is quite limited compared to the range of `Duration`
/// -- only about 16.8ms of exact nanosecond precision -- this method currently forwards
/// to [`mul_f64`][Self::mul_f64] for greater accuracy.
///
/// # Panics
/// This method will panic if result is negative, overflows `Duration` or not finite.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 700_000_000);
/// // Note that this `3.14_f32` argument already has more floating-point
/// // representation error than a direct `3.14_f64` would, so the result
/// // is slightly different from the ideal 8.478s.
/// assert_eq!(dur.mul_f32(3.14), Duration::new(8, 478_000_283));
/// assert_eq!(dur.mul_f32(3.14e5), Duration::new(847_800, 0));
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn mul_f32(self, rhs: f32) -> Duration {
self.mul_f64(rhs.into())
}
/// Divides `Duration` by `f64`.
///
/// # Panics
/// This method will panic if result is negative, overflows `Duration` or not finite.
///
/// # Examples
///
/// ```
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 700_000_000);
/// assert_eq!(dur.div_f64(3.14), Duration::new(0, 859_872_611));
/// assert_eq!(dur.div_f64(3.14e5), Duration::new(0, 8_599));
/// ```
///
/// Note that `f64` does not have enough bits ([`f64::MANTISSA_DIGITS`]) to represent the full
/// range of possible `Duration` with nanosecond precision, so rounding may occur even for
/// trivial operations like dividing by 1.
///
/// ```
/// # #![feature(float_exact_integer_constants)]
/// use std::time::Duration;
///
/// // This is about 14.9 weeks, remaining precise to the nanosecond:
/// let weeks = Duration::from_nanos(f64::MAX_EXACT_INTEGER as u64);
/// assert_eq!(weeks, weeks.div_f64(1.0));
///
/// // A larger value incurs rounding in the floating-point operation:
/// let weeks = Duration::from_nanos(u64::MAX);
/// assert_ne!(weeks, weeks.div_f64(1.0));
///
/// // This is over 285 million years, remaining precise to the second:
/// let years = Duration::from_secs(f64::MAX_EXACT_INTEGER as u64);
/// assert_eq!(years, years.div_f64(1.0));
///
/// // And again larger values incur rounding:
/// let years = Duration::from_secs(u64::MAX / 2);
/// assert_ne!(years, years.div_f64(1.0));
/// ```
///
/// ```should_panic
/// # use std::time::Duration;
/// // In the extreme, rounding can even overflow `Duration`, which panics.
/// let _ = Duration::from_secs(u64::MAX).div_f64(1.0);
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn div_f64(self, rhs: f64) -> Duration {
Duration::from_secs_f64(self.as_secs_f64() / rhs)
}
/// Divides `Duration` by `f32`.
///
/// Since the significand of `f32` is quite limited compared to the range of `Duration`
/// -- only about 16.8ms of exact nanosecond precision -- this method currently forwards
/// to [`div_f64`][Self::div_f64] for greater accuracy.
///
/// # Panics
/// This method will panic if result is negative, overflows `Duration` or not finite.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 700_000_000);
/// // Note that this `3.14_f32` argument already has more floating-point
/// // representation error than a direct `3.14_f64` would, so the result
/// // is slightly different from the ideally rounded 0.859_872_611.
/// assert_eq!(dur.div_f32(3.14), Duration::new(0, 859_872_583));
/// assert_eq!(dur.div_f32(3.14e5), Duration::new(0, 8_599));
/// ```
#[stable(feature = "duration_float", since = "1.38.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn div_f32(self, rhs: f32) -> Duration {
self.div_f64(rhs.into())
}
/// Divides `Duration` by `Duration` and returns `f64`.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let dur1 = Duration::new(2, 700_000_000);
/// let dur2 = Duration::new(5, 400_000_000);
/// assert_eq!(dur1.div_duration_f64(dur2), 0.5);
/// ```
#[stable(feature = "div_duration", since = "1.80.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_float", since = "1.83.0")]
pub const fn div_duration_f64(self, rhs: Duration) -> f64 {
let self_nanos =
(self.secs as f64) * (NANOS_PER_SEC as f64) + (self.nanos.as_inner() as f64);
let rhs_nanos = (rhs.secs as f64) * (NANOS_PER_SEC as f64) + (rhs.nanos.as_inner() as f64);
self_nanos / rhs_nanos
}
/// Divides `Duration` by `Duration` and returns `f32`.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let dur1 = Duration::new(2, 700_000_000);
/// let dur2 = Duration::new(5, 400_000_000);
/// assert_eq!(dur1.div_duration_f32(dur2), 0.5);
/// ```
#[stable(feature = "div_duration", since = "1.80.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_const_stable(feature = "duration_consts_float", since = "1.83.0")]
pub const fn div_duration_f32(self, rhs: Duration) -> f32 {
let self_nanos =
(self.secs as f32) * (NANOS_PER_SEC as f32) + (self.nanos.as_inner() as f32);
let rhs_nanos = (rhs.secs as f32) * (NANOS_PER_SEC as f32) + (rhs.nanos.as_inner() as f32);
self_nanos / rhs_nanos
}
/// Divides `Duration` by `Duration` and returns `u128`, rounding the result towards zero.
///
/// # Examples
/// ```
/// #![feature(duration_integer_division)]
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 0);
/// assert_eq!(dur.div_duration_floor(Duration::new(1, 000_000_001)), 1);
/// assert_eq!(dur.div_duration_floor(Duration::new(1, 000_000_000)), 2);
/// assert_eq!(dur.div_duration_floor(Duration::new(0, 999_999_999)), 2);
/// ```
#[unstable(feature = "duration_integer_division", issue = "149573")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn div_duration_floor(self, rhs: Duration) -> u128 {
self.as_nanos().div_floor(rhs.as_nanos())
}
/// Divides `Duration` by `Duration` and returns `u128`, rounding the result towards positive infinity.
///
/// # Examples
/// ```
/// #![feature(duration_integer_division)]
/// use std::time::Duration;
///
/// let dur = Duration::new(2, 0);
/// assert_eq!(dur.div_duration_ceil(Duration::new(1, 000_000_001)), 2);
/// assert_eq!(dur.div_duration_ceil(Duration::new(1, 000_000_000)), 2);
/// assert_eq!(dur.div_duration_ceil(Duration::new(0, 999_999_999)), 3);
/// ```
#[unstable(feature = "duration_integer_division", issue = "149573")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn div_duration_ceil(self, rhs: Duration) -> u128 {
self.as_nanos().div_ceil(rhs.as_nanos())
}
}
#[stable(feature = "duration", since = "1.3.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl Add for Duration {
type Output = Duration;
#[inline]
fn add(self, rhs: Duration) -> Duration {
self.checked_add(rhs).expect("overflow when adding durations")
}
}
#[stable(feature = "time_augmented_assignment", since = "1.9.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl AddAssign for Duration {
#[inline]
fn add_assign(&mut self, rhs: Duration) {
*self = *self + rhs;
}
}
#[stable(feature = "duration", since = "1.3.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl Sub for Duration {
type Output = Duration;
#[inline]
fn sub(self, rhs: Duration) -> Duration {
self.checked_sub(rhs).expect("overflow when subtracting durations")
}
}
#[stable(feature = "time_augmented_assignment", since = "1.9.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl SubAssign for Duration {
#[inline]
fn sub_assign(&mut self, rhs: Duration) {
*self = *self - rhs;
}
}
#[stable(feature = "duration", since = "1.3.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl Mul<u32> for Duration {
type Output = Duration;
#[inline]
fn mul(self, rhs: u32) -> Duration {
self.checked_mul(rhs).expect("overflow when multiplying duration by scalar")
}
}
#[stable(feature = "symmetric_u32_duration_mul", since = "1.31.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl Mul<Duration> for u32 {
type Output = Duration;
#[inline]
fn mul(self, rhs: Duration) -> Duration {
rhs * self
}
}
#[stable(feature = "time_augmented_assignment", since = "1.9.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl MulAssign<u32> for Duration {
#[inline]
fn mul_assign(&mut self, rhs: u32) {
*self = *self * rhs;
}
}
#[stable(feature = "duration", since = "1.3.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl Div<u32> for Duration {
type Output = Duration;
#[inline]
#[track_caller]
fn div(self, rhs: u32) -> Duration {
self.checked_div(rhs).expect("divide by zero error when dividing duration by scalar")
}
}
#[stable(feature = "time_augmented_assignment", since = "1.9.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
const impl DivAssign<u32> for Duration {
#[inline]
#[track_caller]
fn div_assign(&mut self, rhs: u32) {
*self = *self / rhs;
}
}
macro_rules! sum_durations {
($iter:expr) => {{
let mut total_secs: u64 = 0;
let mut total_nanos: u64 = 0;
for entry in $iter {
total_secs =
total_secs.checked_add(entry.secs).expect("overflow in iter::sum over durations");
total_nanos = match total_nanos.checked_add(entry.nanos.as_inner() as u64) {
Some(n) => n,
None => {
total_secs = total_secs
.checked_add(total_nanos / NANOS_PER_SEC as u64)
.expect("overflow in iter::sum over durations");
(total_nanos % NANOS_PER_SEC as u64) + entry.nanos.as_inner() as u64
}
};
}
total_secs = total_secs
.checked_add(total_nanos / NANOS_PER_SEC as u64)
.expect("overflow in iter::sum over durations");
total_nanos %= NANOS_PER_SEC as u64;
Duration::new(total_secs, total_nanos as u32)
}};
}
#[stable(feature = "duration_sum", since = "1.16.0")]
impl Sum for Duration {
fn sum<I: Iterator<Item = Duration>>(iter: I) -> Duration {
sum_durations!(iter)
}
}
#[stable(feature = "duration_sum", since = "1.16.0")]
impl<'a> Sum<&'a Duration> for Duration {
fn sum<I: Iterator<Item = &'a Duration>>(iter: I) -> Duration {
sum_durations!(iter)
}
}
#[stable(feature = "duration_debug_impl", since = "1.27.0")]
impl fmt::Debug for Duration {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
/// Formats a floating point number in decimal notation.
///
/// The number is given as the `integer_part` and a fractional part.
/// The value of the fractional part is `fractional_part / divisor`. So
/// `integer_part` = 3, `fractional_part` = 12 and `divisor` = 100
/// represents the number `3.012`. Trailing zeros are omitted.
///
/// `divisor` must not be above 100_000_000. It also should be a power
/// of 10, everything else doesn't make sense. `fractional_part` has
/// to be less than `10 * divisor`!
///
/// A prefix and postfix may be added. The whole thing is padded
/// to the formatter's `width`, if specified.
fn fmt_decimal(
f: &mut fmt::Formatter<'_>,
integer_part: u64,
mut fractional_part: u32,
mut divisor: u32,
prefix: &str,
postfix: &str,
) -> fmt::Result {
// Encode the fractional part into a temporary buffer. The buffer
// only need to hold 9 elements, because `fractional_part` has to
// be smaller than 10^9. The buffer is prefilled with '0' digits
// to simplify the code below.
let mut buf = [b'0'; 9];
// The next digit is written at this position
let mut pos = 0;
// We keep writing digits into the buffer while there are non-zero
// digits left and we haven't written enough digits yet.
while fractional_part > 0 && pos < f.precision().unwrap_or(9) {
// Write new digit into the buffer
buf[pos] = b'0' + (fractional_part / divisor) as u8;
fractional_part %= divisor;
divisor /= 10;
pos += 1;
}
// If a precision < 9 was specified, there may be some non-zero
// digits left that weren't written into the buffer. In that case we
// need to perform rounding to match the semantics of printing
// normal floating point numbers. However, we only need to do work
// when rounding up. This happens if the first digit of the
// remaining ones is >= 5. When the first digit is exactly 5, rounding
// follows IEEE-754 round-ties-to-even semantics: we only round up
// if the last written digit is odd.
let integer_part = if fractional_part > 0 && fractional_part >= divisor * 5 {
// For ties (fractional_part == divisor * 5), only round up if last digit is odd
let is_tie = fractional_part == divisor * 5;
let last_digit_is_odd = if pos > 0 {
(buf[pos - 1] - b'0') % 2 == 1
} else {
// No fractional digits - check the integer part
(integer_part % 2) == 1
};
if is_tie && !last_digit_is_odd {
Some(integer_part)
} else {
// Round up the number contained in the buffer. We go through
// the buffer backwards and keep track of the carry.
let mut rev_pos = pos;
let mut carry = true;
while carry && rev_pos > 0 {
rev_pos -= 1;
// If the digit in the buffer is not '9', we just need to
// increment it and can stop then (since we don't have a
// carry anymore). Otherwise, we set it to '0' (overflow)
// and continue.
if buf[rev_pos] < b'9' {
buf[rev_pos] += 1;
carry = false;
} else {
buf[rev_pos] = b'0';
}
}
// If we still have the carry bit set, that means that we set
// the whole buffer to '0's and need to increment the integer
// part.
if carry {
// If `integer_part == u64::MAX` and precision < 9, any
// carry of the overflow during rounding of the
// `fractional_part` into the `integer_part` will cause the
// `integer_part` itself to overflow. Avoid this by using an
// `Option<u64>`, with `None` representing `u64::MAX + 1`.
integer_part.checked_add(1)
} else {
Some(integer_part)
}
}
} else {
Some(integer_part)
};
// Determine the end of the buffer: if precision is set, we just
// use as many digits from the buffer (capped to 9). If it isn't
// set, we only use all digits up to the last non-zero one.
let end = f.precision().map(|p| crate::cmp::min(p, 9)).unwrap_or(pos);
// This closure emits the formatted duration without emitting any
// padding (padding is calculated below).
let emit_without_padding = |f: &mut fmt::Formatter<'_>| {
if let Some(integer_part) = integer_part {
write!(f, "{}{}", prefix, integer_part)?;
} else {
// u64::MAX + 1 == 18446744073709551616
write!(f, "{}18446744073709551616", prefix)?;
}
// Write the decimal point and the fractional part (if any).
if end > 0 {
// SAFETY: We are only writing ASCII digits into the buffer and
// it was initialized with '0's, so it contains valid UTF8.
let s = unsafe { crate::str::from_utf8_unchecked(&buf[..end]) };
// If the user request a precision > 9, we pad '0's at the end.
let w = f.precision().unwrap_or(pos);
write!(f, ".{:0<width$}", s, width = w)?;
}
write!(f, "{}", postfix)
};
match f.width() {
None => {
// No `width` specified. There's no need to calculate the
// length of the output in this case, just emit it.
emit_without_padding(f)
}
Some(requested_w) => {
// A `width` was specified. Calculate the actual width of
// the output in order to calculate the required padding.
// It consists of 4 parts:
// 1. The prefix: is either "+" or "", so we can just use len().
// 2. The postfix: can be "µs" so we have to count UTF8 characters.
let mut actual_w = prefix.len() + postfix.chars().count();
// 3. The integer part:
if let Some(integer_part) = integer_part {
if let Some(log) = integer_part.checked_ilog10() {
// integer_part is > 0, so has length log10(x)+1
actual_w += 1 + log as usize;
} else {
// integer_part is 0, so has length 1.
actual_w += 1;
}
} else {
// integer_part is u64::MAX + 1, so has length 20
actual_w += 20;
}
// 4. The fractional part (if any):
if end > 0 {
let frac_part_w = f.precision().unwrap_or(pos);
actual_w += 1 + frac_part_w;
}
if requested_w <= actual_w {
// Output is already longer than `width`, so don't pad.
emit_without_padding(f)
} else {
// We need to add padding. Use the `Formatter::padding` helper function.
let default_align = fmt::Alignment::Left;
let post_padding =
f.padding((requested_w - actual_w) as u16, default_align)?;
emit_without_padding(f)?;
post_padding.write(f)
}
}
}
}
// Print leading '+' sign if requested
let prefix = if f.sign_plus() { "+" } else { "" };
if self.secs > 0 {
fmt_decimal(f, self.secs, self.nanos.as_inner(), NANOS_PER_SEC / 10, prefix, "s")
} else if self.nanos.as_inner() >= NANOS_PER_MILLI {
fmt_decimal(
f,
(self.nanos.as_inner() / NANOS_PER_MILLI) as u64,
self.nanos.as_inner() % NANOS_PER_MILLI,
NANOS_PER_MILLI / 10,
prefix,
"ms",
)
} else if self.nanos.as_inner() >= NANOS_PER_MICRO {
fmt_decimal(
f,
(self.nanos.as_inner() / NANOS_PER_MICRO) as u64,
self.nanos.as_inner() % NANOS_PER_MICRO,
NANOS_PER_MICRO / 10,
prefix,
"µs",
)
} else {
fmt_decimal(f, self.nanos.as_inner() as u64, 0, 1, prefix, "ns")
}
}
}
/// An error which can be returned when converting a floating-point value of seconds
/// into a [`Duration`].
///
/// This error is used as the error type for [`Duration::try_from_secs_f32`] and
/// [`Duration::try_from_secs_f64`].
///
/// # Example
///
/// ```
/// use std::time::Duration;
///
/// if let Err(e) = Duration::try_from_secs_f32(-1.0) {
/// println!("Failed conversion to Duration: {e}");
/// }
/// ```
#[derive(Debug, Clone, PartialEq, Eq)]
#[stable(feature = "duration_checked_float", since = "1.66.0")]
pub struct TryFromFloatSecsError {
kind: TryFromFloatSecsErrorKind,
}
#[stable(feature = "duration_checked_float", since = "1.66.0")]
impl fmt::Display for TryFromFloatSecsError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self.kind {
TryFromFloatSecsErrorKind::Negative => {
"cannot convert float seconds to Duration: value is negative"
}
TryFromFloatSecsErrorKind::OverflowOrNan => {
"cannot convert float seconds to Duration: value is either too big or NaN"
}
}
.fmt(f)
}
}
#[derive(Debug, Clone, PartialEq, Eq)]
enum TryFromFloatSecsErrorKind {
// Value is negative.
Negative,
// Value is either too big to be represented as `Duration` or `NaN`.
OverflowOrNan,
}
macro_rules! try_from_secs {
(
secs = $secs: expr,
mantissa_bits = $mant_bits: literal,
exponent_bits = $exp_bits: literal,
offset = $offset: literal,
bits_ty = $bits_ty:ty,
double_ty = $double_ty:ty,
) => {{
const MIN_EXP: i16 = 1 - (1i16 << $exp_bits) / 2;
const MANT_MASK: $bits_ty = (1 << $mant_bits) - 1;
const EXP_MASK: $bits_ty = (1 << $exp_bits) - 1;
if $secs < 0.0 {
return Err(TryFromFloatSecsError { kind: TryFromFloatSecsErrorKind::Negative });
}
let bits = $secs.to_bits();
let mant = (bits & MANT_MASK) | (MANT_MASK + 1);
let exp = ((bits >> $mant_bits) & EXP_MASK) as i16 + MIN_EXP;
let (secs, nanos) = if exp < -31 {
// the input represents less than 1ns and can not be rounded to it
(0u64, 0u32)
} else if exp < 0 {
// the input is less than 1 second
let t = <$double_ty>::from(mant) << ($offset + exp);
let nanos_offset = $mant_bits + $offset;
let nanos_tmp = u128::from(NANOS_PER_SEC) * u128::from(t);
let nanos = (nanos_tmp >> nanos_offset) as u32;
let rem_mask = (1 << nanos_offset) - 1;
let rem_msb_mask = 1 << (nanos_offset - 1);
let rem = nanos_tmp & rem_mask;
let is_tie = rem == rem_msb_mask;
let is_even = (nanos & 1) == 0;
let rem_msb = nanos_tmp & rem_msb_mask == 0;
let add_ns = !(rem_msb || (is_even && is_tie));
// f32 does not have enough precision to trigger the second branch
// since it can not represent numbers between 0.999_999_940_395 and 1.0.
let nanos = nanos + add_ns as u32;
if ($mant_bits == 23) || (nanos != NANOS_PER_SEC) { (0, nanos) } else { (1, 0) }
} else if exp < $mant_bits {
let secs = u64::from(mant >> ($mant_bits - exp));
let t = <$double_ty>::from((mant << exp) & MANT_MASK);
let nanos_offset = $mant_bits;
let nanos_tmp = <$double_ty>::from(NANOS_PER_SEC) * t;
let nanos = (nanos_tmp >> nanos_offset) as u32;
let rem_mask = (1 << nanos_offset) - 1;
let rem_msb_mask = 1 << (nanos_offset - 1);
let rem = nanos_tmp & rem_mask;
let is_tie = rem == rem_msb_mask;
let is_even = (nanos & 1) == 0;
let rem_msb = nanos_tmp & rem_msb_mask == 0;
let add_ns = !(rem_msb || (is_even && is_tie));
// f32 does not have enough precision to trigger the second branch.
// For example, it can not represent numbers between 1.999_999_880...
// and 2.0. Bigger values result in even smaller precision of the
// fractional part.
let nanos = nanos + add_ns as u32;
if ($mant_bits == 23) || (nanos != NANOS_PER_SEC) {
(secs, nanos)
} else {
(secs + 1, 0)
}
} else if exp < 64 {
// the input has no fractional part
let secs = u64::from(mant) << (exp - $mant_bits);
(secs, 0)
} else {
return Err(TryFromFloatSecsError { kind: TryFromFloatSecsErrorKind::OverflowOrNan });
};
Ok(Duration::new(secs, nanos))
}};
}
impl Duration {
/// The checked version of [`from_secs_f32`].
///
/// [`from_secs_f32`]: Duration::from_secs_f32
///
/// This constructor will return an `Err` if `secs` is negative, overflows `Duration` or not finite.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let res = Duration::try_from_secs_f32(0.0);
/// assert_eq!(res, Ok(Duration::new(0, 0)));
/// let res = Duration::try_from_secs_f32(1e-20);
/// assert_eq!(res, Ok(Duration::new(0, 0)));
/// let res = Duration::try_from_secs_f32(4.2e-7);
/// assert_eq!(res, Ok(Duration::new(0, 420)));
/// let res = Duration::try_from_secs_f32(2.7);
/// assert_eq!(res, Ok(Duration::new(2, 700_000_048)));
/// let res = Duration::try_from_secs_f32(3e10);
/// assert_eq!(res, Ok(Duration::new(30_000_001_024, 0)));
/// // subnormal float:
/// let res = Duration::try_from_secs_f32(f32::from_bits(1));
/// assert_eq!(res, Ok(Duration::new(0, 0)));
///
/// let res = Duration::try_from_secs_f32(-5.0);
/// assert!(res.is_err());
/// let res = Duration::try_from_secs_f32(f32::NAN);
/// assert!(res.is_err());
/// let res = Duration::try_from_secs_f32(2e19);
/// assert!(res.is_err());
///
/// // the conversion uses rounding with tie resolution to even
/// let res = Duration::try_from_secs_f32(0.999e-9);
/// assert_eq!(res, Ok(Duration::new(0, 1)));
///
/// // this float represents exactly 976562.5e-9
/// let val = f32::from_bits(0x3A80_0000);
/// let res = Duration::try_from_secs_f32(val);
/// assert_eq!(res, Ok(Duration::new(0, 976_562)));
///
/// // this float represents exactly 2929687.5e-9
/// let val = f32::from_bits(0x3B40_0000);
/// let res = Duration::try_from_secs_f32(val);
/// assert_eq!(res, Ok(Duration::new(0, 2_929_688)));
///
/// // this float represents exactly 1.000_976_562_5
/// let val = f32::from_bits(0x3F802000);
/// let res = Duration::try_from_secs_f32(val);
/// assert_eq!(res, Ok(Duration::new(1, 976_562)));
///
/// // this float represents exactly 1.002_929_687_5
/// let val = f32::from_bits(0x3F806000);
/// let res = Duration::try_from_secs_f32(val);
/// assert_eq!(res, Ok(Duration::new(1, 2_929_688)));
/// ```
#[stable(feature = "duration_checked_float", since = "1.66.0")]
#[inline]
pub fn try_from_secs_f32(secs: f32) -> Result<Duration, TryFromFloatSecsError> {
try_from_secs!(
secs = secs,
mantissa_bits = 23,
exponent_bits = 8,
offset = 41,
bits_ty = u32,
double_ty = u64,
)
}
/// The checked version of [`from_secs_f64`].
///
/// [`from_secs_f64`]: Duration::from_secs_f64
///
/// This constructor will return an `Err` if `secs` is negative, overflows `Duration` or not finite.
///
/// # Examples
/// ```
/// use std::time::Duration;
///
/// let res = Duration::try_from_secs_f64(0.0);
/// assert_eq!(res, Ok(Duration::new(0, 0)));
/// let res = Duration::try_from_secs_f64(1e-20);
/// assert_eq!(res, Ok(Duration::new(0, 0)));
/// let res = Duration::try_from_secs_f64(4.2e-7);
/// assert_eq!(res, Ok(Duration::new(0, 420)));
/// let res = Duration::try_from_secs_f64(2.7);
/// assert_eq!(res, Ok(Duration::new(2, 700_000_000)));
/// let res = Duration::try_from_secs_f64(3e10);
/// assert_eq!(res, Ok(Duration::new(30_000_000_000, 0)));
/// // subnormal float
/// let res = Duration::try_from_secs_f64(f64::from_bits(1));
/// assert_eq!(res, Ok(Duration::new(0, 0)));
///
/// let res = Duration::try_from_secs_f64(-5.0);
/// assert!(res.is_err());
/// let res = Duration::try_from_secs_f64(f64::NAN);
/// assert!(res.is_err());
/// let res = Duration::try_from_secs_f64(2e19);
/// assert!(res.is_err());
///
/// // the conversion uses rounding with tie resolution to even
/// let res = Duration::try_from_secs_f64(0.999e-9);
/// assert_eq!(res, Ok(Duration::new(0, 1)));
/// let res = Duration::try_from_secs_f64(0.999_999_999_499);
/// assert_eq!(res, Ok(Duration::new(0, 999_999_999)));
/// let res = Duration::try_from_secs_f64(0.999_999_999_501);
/// assert_eq!(res, Ok(Duration::new(1, 0)));
/// let res = Duration::try_from_secs_f64(42.999_999_999_499);
/// assert_eq!(res, Ok(Duration::new(42, 999_999_999)));
/// let res = Duration::try_from_secs_f64(42.999_999_999_501);
/// assert_eq!(res, Ok(Duration::new(43, 0)));
///
/// // this float represents exactly 976562.5e-9
/// let val = f64::from_bits(0x3F50_0000_0000_0000);
/// let res = Duration::try_from_secs_f64(val);
/// assert_eq!(res, Ok(Duration::new(0, 976_562)));
///
/// // this float represents exactly 2929687.5e-9
/// let val = f64::from_bits(0x3F68_0000_0000_0000);
/// let res = Duration::try_from_secs_f64(val);
/// assert_eq!(res, Ok(Duration::new(0, 2_929_688)));
///
/// // this float represents exactly 1.000_976_562_5
/// let val = f64::from_bits(0x3FF0_0400_0000_0000);
/// let res = Duration::try_from_secs_f64(val);
/// assert_eq!(res, Ok(Duration::new(1, 976_562)));
///
/// // this float represents exactly 1.002_929_687_5
/// let val = f64::from_bits(0x3_FF00_C000_0000_000);
/// let res = Duration::try_from_secs_f64(val);
/// assert_eq!(res, Ok(Duration::new(1, 2_929_688)));
/// ```
#[stable(feature = "duration_checked_float", since = "1.66.0")]
#[inline]
pub fn try_from_secs_f64(secs: f64) -> Result<Duration, TryFromFloatSecsError> {
try_from_secs!(
secs = secs,
mantissa_bits = 52,
exponent_bits = 11,
offset = 44,
bits_ty = u64,
double_ty = u128,
)
}
}