feat(core): Add casting and correct subtraction/cmp

argus-core/src/signals/cast.rs

@@ -0,0 +1,80 @@
+use itertools::Itertools;
+use num_traits::{Num, NumCast};
+
+use crate::signals::traits::SignalNumCast;
+use crate::signals::{AnySignal, ConstantSignal, Signal};
+
+macro_rules! impl_cast {
+    ($type:ty) => {
+        paste::paste! {
+            #[inline]
+            fn [<to_ $type>](&self) -> Option<Signal<$type>> {
+                let samples = self
+                    .iter()
+                    .map_while(|(&t, &v)| num_traits::cast::<_, $type>(v).map(|v| (t, v)))
+                    .collect_vec();
+                if samples.len() < self.time_points.len() {
+                    // Failed to convert some item
+                    None
+                } else {
+                    Some(samples.into_iter().collect())
+                }
+            }
+        }
+    };
+}
+
+impl<T> SignalNumCast for Signal<T>
+where
+    T: Num + NumCast + Copy,
+{
+    type Value = T;
+
+    type Output<U> = Signal<U>
+    where
+        U: Num + NumCast + Copy;
+
+    impl_cast!(i8);
+    impl_cast!(i16);
+    impl_cast!(i32);
+    impl_cast!(i64);
+    impl_cast!(u8);
+    impl_cast!(u16);
+    impl_cast!(u32);
+    impl_cast!(u64);
+    impl_cast!(f32);
+    impl_cast!(f64);
+}
+
+macro_rules! impl_cast {
+    ($type:ty) => {
+        paste::paste! {
+            #[inline]
+            fn [<to_ $type>](&self) -> Option<ConstantSignal<$type>> {
+                num_traits::cast::<_, $type>(self.value).map(ConstantSignal::new)
+            }
+        }
+    };
+}
+
+impl<T> SignalNumCast for ConstantSignal<T>
+where
+    T: Num + NumCast + Copy,
+{
+    type Value = T;
+
+    type Output<U> = ConstantSignal<U>
+    where
+        U: Num + NumCast + Copy;
+
+    impl_cast!(i8);
+    impl_cast!(i16);
+    impl_cast!(i32);
+    impl_cast!(i64);
+    impl_cast!(u8);
+    impl_cast!(u16);
+    impl_cast!(u32);
+    impl_cast!(u64);
+    impl_cast!(f32);
+    impl_cast!(f64);
+}