Generic add/sub

src/instant.rs

@@ -1,12 +1,13 @@
 //! An instant of time
 
 use crate::{
-    duration::{self, Duration},
+    duration::{self, Duration, Generic},
     fixed_point::FixedPoint,
+    time_int::TimeInt,
 };
 use core::{
     cmp::Ordering,
-    convert::TryFrom,
+    convert::{TryFrom, TryInto},
     hash::{Hash, Hasher},
     ops,
 };
@@ -189,6 +190,23 @@ impl<Clock: crate::Clock> Instant<Clock> {
         }
     }
 
+    /// `Generic` version of `checked_add`.
+    pub fn checked_add_generic<T: TimeInt>(self, duration: Generic<T>) -> Option<Self>
+    where
+        Clock::T: core::ops::Div<Output = Clock::T>,
+        Generic<Clock::T>: TryFrom<Generic<T>>,
+    {
+        let clock_dur: Generic<Clock::T> = duration.try_into().ok()?;
+        let add_ticks: Clock::T = *clock_dur.integer();
+        if add_ticks <= (<Clock::T as num::Bounded>::max_value() / 2.into()) {
+            Some(Self {
+                ticks: self.ticks.wrapping_add(&add_ticks),
+            })
+        } else {
+            None
+        }
+    }
+
     /// This `Instant` - [`Duration`] = earlier `Instant`
     ///
     /// Returns [`None`] if the [`Duration`] is too large
@@ -226,6 +244,23 @@ impl<Clock: crate::Clock> Instant<Clock> {
             None
         }
     }
+
+    /// `Generic` version of `checked_sub`.
+    pub fn checked_sub_generic<T: TimeInt>(self, duration: Generic<T>) -> Option<Self>
+    where
+        Clock::T: core::ops::Div<Output = Clock::T>,
+        Generic<Clock::T>: TryFrom<Generic<T>>,
+    {
+        let clock_dur: Generic<Clock::T> = duration.try_into().ok()?;
+        let sub_ticks: Clock::T = *clock_dur.integer();
+        if sub_ticks <= (<Clock::T as num::Bounded>::max_value() / 2.into()) {
+            Some(Self {
+                ticks: self.ticks.wrapping_sub(&sub_ticks),
+            })
+        } else {
+            None
+        }
+    }
 }
 
 impl<Clock: crate::Clock> Copy for Instant<Clock> {}
@@ -342,6 +377,21 @@ where
     }
 }
 
+impl<Clock: crate::Clock, T: TimeInt> ops::Add<Generic<T>> for Instant<Clock>
+where
+    Generic<Clock::T>: TryFrom<Generic<T>>,
+{
+    type Output = Self;
+
+    fn add(self, rhs: Generic<T>) -> Self::Output {
+        if let Some(v) = self.checked_add_generic(rhs) {
+            v
+        } else {
+            panic!("Add failed")
+        }
+    }
+}
+
 impl<Clock: crate::Clock, Dur: Duration> ops::Sub<Dur> for Instant<Clock>
 where
     Clock::T: TryFrom<Dur::T>,
@@ -404,6 +454,21 @@ where
     }
 }
 
+impl<Clock: crate::Clock, T: TimeInt> ops::Sub<Generic<T>> for Instant<Clock>
+where
+    Generic<Clock::T>: TryFrom<Generic<T>>,
+{
+    type Output = Self;
+
+    fn sub(self, rhs: Generic<T>) -> Self::Output {
+        if let Some(v) = self.checked_sub_generic(rhs) {
+            v
+        } else {
+            panic!("Sub failed")
+        }
+    }
+}
+
 impl<Clock: crate::Clock> ops::Sub<Instant<Clock>> for Instant<Clock> {
     type Output = duration::Generic<Clock::T>;