Port Duration::from_secs_f32|64 from std

This ports the algorithm for constructing `Duration` from floating point
seconds from `std`. The new algorithm in `std` uses bit manipulation to
construct the `Duration` with the most precision possible. Additionally
this adds `saturating` and `checked` variants of those functions.

Original `std` PR: rust-lang/rust#90247

Co-authored-by: Ted Wollman <25165500+TheTedder@users.noreply.github.com>

benchmarks/duration.rs

@@ -127,6 +127,26 @@ setup_benchmark! {
         ben.iter(|| Duration::seconds_f32(-0.5));
     }
 
+    fn saturating_seconds_f64(ben: &mut Bencher<'_>) {
+        ben.iter(|| Duration::saturating_seconds_f64(0.5));
+        ben.iter(|| Duration::saturating_seconds_f64(-0.5));
+    }
+
+    fn saturating_seconds_f32(ben: &mut Bencher<'_>) {
+        ben.iter(|| Duration::saturating_seconds_f32(0.5));
+        ben.iter(|| Duration::saturating_seconds_f32(-0.5));
+    }
+
+    fn checked_seconds_f64(ben: &mut Bencher<'_>) {
+        ben.iter(|| Duration::checked_seconds_f64(0.5));
+        ben.iter(|| Duration::checked_seconds_f64(-0.5));
+    }
+
+    fn checked_seconds_f32(ben: &mut Bencher<'_>) {
+        ben.iter(|| Duration::checked_seconds_f32(0.5));
+        ben.iter(|| Duration::checked_seconds_f32(-0.5));
+    }
+
     fn milliseconds(ben: &mut Bencher<'_>) {
         ben.iter(|| Duration::milliseconds(1));
         ben.iter(|| Duration::milliseconds(-1));

tests/duration.rs

@@ -189,6 +189,26 @@ fn seconds_f64() {
     assert_panic!(Duration::seconds_f64(f64::NAN));
 }
 
+#[test]
+fn saturating_seconds_f64() {
+    assert_eq!(Duration::saturating_seconds_f64(0.5), 0.5.seconds());
+    assert_eq!(Duration::saturating_seconds_f64(-0.5), (-0.5).seconds());
+
+    assert_eq!(Duration::saturating_seconds_f64(f64::MAX), Duration::MAX);
+    assert_eq!(Duration::saturating_seconds_f64(f64::MIN), Duration::MIN);
+    assert_eq!(Duration::saturating_seconds_f64(f64::NAN), Duration::ZERO);
+}
+
+#[test]
+fn checked_seconds_f64() {
+    assert_eq!(Duration::checked_seconds_f64(0.5), Some(0.5.seconds()));
+    assert_eq!(Duration::checked_seconds_f64(-0.5), Some((-0.5).seconds()));
+
+    assert_eq!(Duration::checked_seconds_f64(f64::MAX), None);
+    assert_eq!(Duration::checked_seconds_f64(f64::MIN), None);
+    assert_eq!(Duration::checked_seconds_f64(f64::NAN), None);
+}
+
 #[test]
 #[allow(clippy::float_cmp)]
 fn as_seconds_f64() {
@@ -210,6 +230,26 @@ fn seconds_f32() {
     assert_panic!(Duration::seconds_f32(f32::NAN));
 }
 
+#[test]
+fn saturating_seconds_f32() {
+    assert_eq!(Duration::saturating_seconds_f32(0.5), 0.5.seconds());
+    assert_eq!(Duration::saturating_seconds_f32(-0.5), (-0.5).seconds());
+
+    assert_eq!(Duration::saturating_seconds_f32(f32::MAX), Duration::MAX);
+    assert_eq!(Duration::saturating_seconds_f32(f32::MIN), Duration::MIN);
+    assert_eq!(Duration::saturating_seconds_f32(f32::NAN), Duration::ZERO);
+}
+
+#[test]
+fn checked_seconds_f32() {
+    assert_eq!(Duration::checked_seconds_f32(0.5), Some(0.5.seconds()));
+    assert_eq!(Duration::checked_seconds_f32(-0.5), Some((-0.5).seconds()));
+
+    assert_eq!(Duration::checked_seconds_f32(f32::MAX), None);
+    assert_eq!(Duration::checked_seconds_f32(f32::MIN), None);
+    assert_eq!(Duration::checked_seconds_f32(f32::NAN), None);
+}
+
 #[test]
 #[allow(clippy::float_cmp)]
 fn as_seconds_f32() {