Make remaining methods const

src/datetime/mod.rs

@@ -27,6 +27,7 @@ use crate::naive::{Days, IsoWeek, NaiveDate, NaiveDateTime, NaiveTime};
 #[cfg(feature = "clock")]
 use crate::offset::Local;
 use crate::offset::{FixedOffset, Offset, TimeZone, Utc};
+use crate::try_opt;
 #[allow(deprecated)]
 use crate::Date;
 use crate::{Datelike, Months, Timelike, Weekday};
@@ -626,8 +627,11 @@ impl DateTime<Utc> {
     /// ```
     #[inline]
     #[must_use]
-    pub fn from_timestamp(secs: i64, nsecs: u32) -> Option<Self> {
-        NaiveDateTime::from_timestamp_opt(secs, nsecs).as_ref().map(NaiveDateTime::and_utc)
+    pub const fn from_timestamp(secs: i64, nsecs: u32) -> Option<Self> {
+        Some(DateTime {
+            datetime: try_opt!(NaiveDateTime::from_timestamp_opt(secs, nsecs)),
+            offset: Utc,
+        })
     }
 
     /// Makes a new [`DateTime<Utc>`] from the number of non-leap milliseconds

src/duration.rs

@@ -16,6 +16,8 @@ use core::{fmt, i64};
 #[cfg(feature = "std")]
 use std::error::Error;
 
+use crate::{expect, try_opt};
+
 #[cfg(any(feature = "rkyv", feature = "rkyv-16", feature = "rkyv-32", feature = "rkyv-64"))]
 use rkyv::{Archive, Deserialize, Serialize};
 
@@ -38,15 +40,6 @@ const SECS_PER_DAY: i64 = 86_400;
 /// The number of (non-leap) seconds in a week.
 const SECS_PER_WEEK: i64 = 604_800;
 
-macro_rules! try_opt {
-    ($e:expr) => {
-        match $e {
-            Some(v) => v,
-            None => return None,
-        }
-    };
-}
-
 /// ISO 8601 time duration with nanosecond precision.
 ///
 /// This also allows for negative durations; see individual methods for details.
@@ -82,6 +75,23 @@ pub(crate) const MAX: Duration = Duration {
 };
 
 impl Duration {
+    /// Makes a new `Duration` with given number of seconds and nanoseconds.
+    ///
+    /// # Errors
+    ///
+    /// Returns `None` when the duration is out of bounds, or if `nanos` ≥ 1,000,000,000.
+    pub(crate) const fn new(secs: i64, nanos: u32) -> Option<Duration> {
+        if secs < MIN.secs
+            || secs > MAX.secs
+            || nanos > 1_000_000_000
+            || (secs == MAX.secs && nanos > MAX.nanos as u32)
+            || (secs == MIN.secs && nanos < MIN.nanos as u32)
+        {
+            return None;
+        }
+        Some(Duration { secs, nanos: nanos as i32 })
+    }
+
     /// Makes a new `Duration` with the given number of weeks.
     ///
     /// Equivalent to `Duration::seconds(weeks * 7 * 24 * 60 * 60)` with
@@ -92,8 +102,8 @@ impl Duration {
     /// Panics when the duration is out of bounds.
     #[inline]
     #[must_use]
-    pub fn weeks(weeks: i64) -> Duration {
-        Duration::try_weeks(weeks).expect("Duration::weeks out of bounds")
+    pub const fn weeks(weeks: i64) -> Duration {
+        expect!(Duration::try_weeks(weeks), "Duration::weeks out of bounds")
     }
 
     /// Makes a new `Duration` with the given number of weeks.
@@ -105,8 +115,8 @@ impl Duration {
     ///
     /// Returns `None` when the duration is out of bounds.
     #[inline]
-    pub fn try_weeks(weeks: i64) -> Option<Duration> {
-        weeks.checked_mul(SECS_PER_WEEK).and_then(Duration::try_seconds)
+    pub const fn try_weeks(weeks: i64) -> Option<Duration> {
+        Duration::try_seconds(try_opt!(weeks.checked_mul(SECS_PER_WEEK)))
     }
 
     /// Makes a new `Duration` with the given number of days.
@@ -119,8 +129,8 @@ impl Duration {
     /// Panics when the duration is out of bounds.
     #[inline]
     #[must_use]
-    pub fn days(days: i64) -> Duration {
-        Duration::try_days(days).expect("Duration::days out of bounds")
+    pub const fn days(days: i64) -> Duration {
+        expect!(Duration::try_days(days), "Duration::days out of bounds")
     }
 
     /// Makes a new `Duration` with the given number of days.
@@ -132,8 +142,8 @@ impl Duration {
     ///
     /// Returns `None` when the duration is out of bounds.
     #[inline]
-    pub fn try_days(days: i64) -> Option<Duration> {
-        days.checked_mul(SECS_PER_DAY).and_then(Duration::try_seconds)
+    pub const fn try_days(days: i64) -> Option<Duration> {
+        Duration::try_seconds(try_opt!(days.checked_mul(SECS_PER_DAY)))
     }
 
     /// Makes a new `Duration` with the given number of hours.
@@ -145,8 +155,8 @@ impl Duration {
     /// Panics when the duration is out of bounds.
     #[inline]
     #[must_use]
-    pub fn hours(hours: i64) -> Duration {
-        Duration::try_hours(hours).expect("Duration::hours out of bounds")
+    pub const fn hours(hours: i64) -> Duration {
+        expect!(Duration::try_hours(hours), "Duration::hours out of bounds")
     }
 
     /// Makes a new `Duration` with the given number of hours.
@@ -157,8 +167,8 @@ impl Duration {
     ///
     /// Returns `None` when the duration is out of bounds.
     #[inline]
-    pub fn try_hours(hours: i64) -> Option<Duration> {
-        hours.checked_mul(SECS_PER_HOUR).and_then(Duration::try_seconds)
+    pub const fn try_hours(hours: i64) -> Option<Duration> {
+        Duration::try_seconds(try_opt!(hours.checked_mul(SECS_PER_HOUR)))
     }
 
     /// Makes a new `Duration` with the given number of minutes.
@@ -170,8 +180,8 @@ impl Duration {
     /// Panics when the duration is out of bounds.
     #[inline]
     #[must_use]
-    pub fn minutes(minutes: i64) -> Duration {
-        Duration::try_minutes(minutes).expect("Duration::minutes out of bounds")
+    pub const fn minutes(minutes: i64) -> Duration {
+        expect!(Duration::try_minutes(minutes), "Duration::minutes out of bounds")
     }
 
     /// Makes a new `Duration` with the given number of minutes.
@@ -182,8 +192,8 @@ impl Duration {
     ///
     /// Returns `None` when the duration is out of bounds.
     #[inline]
-    pub fn try_minutes(minutes: i64) -> Option<Duration> {
-        minutes.checked_mul(SECS_PER_MINUTE).and_then(Duration::try_seconds)
+    pub const fn try_minutes(minutes: i64) -> Option<Duration> {
+        Duration::try_seconds(try_opt!(minutes.checked_mul(SECS_PER_MINUTE)))
     }
 
     /// Makes a new `Duration` with the given number of seconds.
@@ -196,8 +206,8 @@ impl Duration {
     /// rounding).
     #[inline]
     #[must_use]
-    pub fn seconds(seconds: i64) -> Duration {
-        Duration::try_seconds(seconds).expect("Duration::seconds out of bounds")
+    pub const fn seconds(seconds: i64) -> Duration {
+        expect!(Duration::try_seconds(seconds), "Duration::seconds out of bounds")
     }
 
     /// Makes a new `Duration` with the given number of seconds.
@@ -208,12 +218,8 @@ impl Duration {
     /// or less than `-i64::MAX / 1_000` seconds (in this context, this is the
     /// same as `i64::MIN / 1_000` due to rounding).
     #[inline]
-    pub fn try_seconds(seconds: i64) -> Option<Duration> {
-        let d = Duration { secs: seconds, nanos: 0 };
-        if d < MIN || d > MAX {
-            return None;
-        }
-        Some(d)
+    pub const fn try_seconds(seconds: i64) -> Option<Duration> {
+        Duration::new(seconds, 0)
     }
 
     /// Makes a new `Duration` with the given number of milliseconds.
@@ -224,8 +230,8 @@ impl Duration {
     /// more than `i64::MAX` milliseconds or less than `-i64::MAX` milliseconds.
     /// Notably, this is not the same as `i64::MIN`.
     #[inline]
-    pub fn milliseconds(milliseconds: i64) -> Duration {
-        Duration::try_milliseconds(milliseconds).expect("Duration::milliseconds out of bounds")
+    pub const fn milliseconds(milliseconds: i64) -> Duration {
+        expect!(Duration::try_milliseconds(milliseconds), "Duration::milliseconds out of bounds")
     }
 
     /// Makes a new `Duration` with the given number of milliseconds.
@@ -236,14 +242,14 @@ impl Duration {
     /// less than `-i64::MAX` milliseconds. Notably, this is not the same as
     /// `i64::MIN`.
     #[inline]
-    pub fn try_milliseconds(milliseconds: i64) -> Option<Duration> {
-        let (secs, millis) = div_mod_floor_64(milliseconds, MILLIS_PER_SEC);
-        let d = Duration { secs, nanos: millis as i32 * NANOS_PER_MILLI };
+    pub const fn try_milliseconds(milliseconds: i64) -> Option<Duration> {
         // We don't need to compare against MAX, as this function accepts an
         // i64, and MAX is aligned to i64::MAX milliseconds.
-        if d < MIN {
+        if milliseconds < -i64::MAX {
             return None;
         }
+        let (secs, millis) = div_mod_floor_64(milliseconds, MILLIS_PER_SEC);
+        let d = Duration { secs, nanos: millis as i32 * NANOS_PER_MILLI };
         Some(d)
     }
 
@@ -344,40 +350,30 @@ impl Duration {
 
     /// Add two `Duration`s, returning `None` if overflow occurred.
     #[must_use]
-    pub fn checked_add(&self, rhs: &Duration) -> Option<Duration> {
-        let mut secs = try_opt!(self.secs.checked_add(rhs.secs));
+    pub const fn checked_add(&self, rhs: &Duration) -> Option<Duration> {
+        // No overflow checks here because we stay comfortably within the range of an `i64`.
+        // Range checks happen in `Duration::new`.
+        let mut secs = self.secs + rhs.secs;
         let mut nanos = self.nanos + rhs.nanos;
         if nanos >= NANOS_PER_SEC {
             nanos -= NANOS_PER_SEC;
-            secs = try_opt!(secs.checked_add(1));
-        }
-        let d = Duration { secs, nanos };
-        // Even if d is within the bounds of i64 seconds,
-        // it might still overflow i64 milliseconds.
-        if d < MIN || d > MAX {
-            None
-        } else {
-            Some(d)
+            secs += 1;
         }
+        Duration::new(secs, nanos as u32)
     }
 
     /// Subtract two `Duration`s, returning `None` if overflow occurred.
     #[must_use]
-    pub fn checked_sub(&self, rhs: &Duration) -> Option<Duration> {
-        let mut secs = try_opt!(self.secs.checked_sub(rhs.secs));
+    pub const fn checked_sub(&self, rhs: &Duration) -> Option<Duration> {
+        // No overflow checks here because we stay comfortably within the range of an `i64`.
+        // Range checks happen in `Duration::new`.
+        let mut secs = self.secs - rhs.secs;
         let mut nanos = self.nanos - rhs.nanos;
         if nanos < 0 {
             nanos += NANOS_PER_SEC;
-            secs = try_opt!(secs.checked_sub(1));
-        }
-        let d = Duration { secs, nanos };
-        // Even if d is within the bounds of i64 seconds,
-        // it might still overflow i64 milliseconds.
-        if d < MIN || d > MAX {
-            None
-        } else {
-            Some(d)
+            secs -= 1;
         }
+        Duration::new(secs, nanos as u32)
     }
 
     /// Returns the `Duration` as an absolute (non-negative) value.
@@ -418,40 +414,48 @@ impl Duration {
     ///
     /// This function errors when original duration is larger than the maximum
     /// value supported for this type.
-    pub fn from_std(duration: StdDuration) -> Result<Duration, OutOfRangeError> {
+    pub const fn from_std(duration: StdDuration) -> Result<Duration, OutOfRangeError> {
         // We need to check secs as u64 before coercing to i64
         if duration.as_secs() > MAX.secs as u64 {
             return Err(OutOfRangeError(()));
         }
-        let d = Duration { secs: duration.as_secs() as i64, nanos: duration.subsec_nanos() as i32 };
-        if d > MAX {
-            return Err(OutOfRangeError(()));
+        match Duration::new(duration.as_secs() as i64, duration.subsec_nanos()) {
+            Some(d) => Ok(d),
+            None => Err(OutOfRangeError(())),
         }
-        Ok(d)
     }
 
     /// Creates a `std::time::Duration` object from `time::Duration`
     ///
     /// This function errors when duration is less than zero. As standard
     /// library implementation is limited to non-negative values.
-    pub fn to_std(&self) -> Result<StdDuration, OutOfRangeError> {
+    pub const fn to_std(&self) -> Result<StdDuration, OutOfRangeError> {
         if self.secs < 0 {
             return Err(OutOfRangeError(()));
         }
         Ok(StdDuration::new(self.secs as u64, self.nanos as u32))
     }
+
+    /// This duplicates `Neg::neg` because trait methods can't be const yet.
+    pub(crate) const fn neg(self) -> Duration {
+        let (secs_diff, nanos) = match self.nanos {
+            0 => (0, 0),
+            nanos => (1, NANOS_PER_SEC - nanos),
+        };
+        Duration { secs: -self.secs - secs_diff, nanos }
+    }
 }
 
 impl Neg for Duration {
     type Output = Duration;
 
     #[inline]
     fn neg(self) -> Duration {
-        if self.nanos == 0 {
-            Duration { secs: -self.secs, nanos: 0 }
-        } else {
-            Duration { secs: -self.secs - 1, nanos: NANOS_PER_SEC - self.nanos }
-        }
+        let (secs_diff, nanos) = match self.nanos {
+            0 => (0, 0),
+            nanos => (1, NANOS_PER_SEC - nanos),
+        };
+        Duration { secs: -self.secs - secs_diff, nanos }
     }
 }
 
@@ -1148,6 +1152,40 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_duration_const() {
+        const ONE_WEEK: Duration = Duration::weeks(1);
+        const ONE_DAY: Duration = Duration::days(1);
+        const ONE_HOUR: Duration = Duration::hours(1);
+        const ONE_MINUTE: Duration = Duration::minutes(1);
+        const ONE_SECOND: Duration = Duration::seconds(1);
+        const ONE_MILLI: Duration = Duration::milliseconds(1);
+        const ONE_MICRO: Duration = Duration::microseconds(1);
+        const ONE_NANO: Duration = Duration::nanoseconds(1);
+        let combo: Duration = ONE_WEEK
+            + ONE_DAY
+            + ONE_HOUR
+            + ONE_MINUTE
+            + ONE_SECOND
+            + ONE_MILLI
+            + ONE_MICRO
+            + ONE_NANO;
+
+        assert!(ONE_WEEK != Duration::zero());
+        assert!(ONE_DAY != Duration::zero());
+        assert!(ONE_HOUR != Duration::zero());
+        assert!(ONE_MINUTE != Duration::zero());
+        assert!(ONE_SECOND != Duration::zero());
+        assert!(ONE_MILLI != Duration::zero());
+        assert!(ONE_MICRO != Duration::zero());
+        assert!(ONE_NANO != Duration::zero());
+        assert_eq!(
+            combo,
+            Duration::seconds(86400 * 7 + 86400 + 3600 + 60 + 1)
+                + Duration::nanoseconds(1 + 1_000 + 1_000_000)
+        );
+    }
+
     #[test]
     #[cfg(feature = "rkyv-validation")]
     fn test_rkyv_validation() {