Initial proof of concept

src/quantity/mod.rs

@@ -0,0 +1,170 @@
+mod irradiance;
+mod resistance;
+mod temperature;
+mod voltage;
+mod volume;
+mod volume_rate;
+mod pressure;
+
+#[cfg(feature = "defmt")]
+pub use defmt_impl::*;
+
+pub use irradiance::*;
+pub use resistance::*;
+pub use temperature::*;
+pub use voltage::*;
+pub use volume::*;
+pub use volume_rate::*;
+pub use pressure::*;
+
+use core::fmt::Display;
+use core::marker::PhantomData;
+use core::ops::{Add, Sub};
+use num_traits::{FromPrimitive, Num, NumCast};
+
+const DECA: u8 = 10;
+const DECI: u8 = 10;
+const HECTO: u8 = 100;
+const CENTI: u8 = 100;
+const KILO: u16 = 1_000;
+const MILLI: u16 = 1_000;
+const MEGA: u32 = 1_000_000;
+const MICRO: u32 = 1_000_000;
+const GIGA: u32 = 1_000_000_000;
+const NANO: u32 = 1_000_000_000;
+
+pub trait Quantity<V: Value>: Copy + PartialEq + PartialOrd + Add + Sub {
+    fn value(self) -> V;
+
+    fn symbol() -> &'static str;
+
+    /// Returns a wrapper that implements [Display] and [defmt::Format] for [Quantity]s with core number values.
+    ///
+    /// - `rounding` - Sets the number of decimal places to round to when formatting (currently ignored with defmt).
+    #[inline(always)]
+    fn fmt(self, rounding: Option<usize>) -> Fmt<V, Self> {
+        Fmt::new(self, rounding)
+    }
+}
+
+pub trait Value: Num + Copy + PartialOrd + FromPrimitive + NumCast + Display {}
+impl<V> Value for V where V: Num + Copy + PartialOrd + FromPrimitive + NumCast + Display {}
+
+#[derive(Copy, Clone)]
+pub struct Fmt<V: Value, Q: Quantity<V>> {
+    quantity: Q,
+    rounding: Option<usize>,
+    _phantom: PhantomData<V>,
+}
+
+impl<V: Value, Q: Quantity<V>> Fmt<V, Q> {
+    #[inline(always)]
+    fn new(quantity: Q, rounding: Option<usize>) -> Self {
+        Self {
+            quantity,
+            rounding,
+            _phantom: PhantomData,
+        }
+    }
+}
+
+impl<V: Value, Q: Quantity<V>> Display for Fmt<V, Q> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        match self.rounding {
+            Some(places) => {
+                write!(f, "{:.prec$} {}", self.quantity.value(), Q::symbol(), prec = places)
+            },
+            None => write!(f, "{} {}", self.quantity.value(), Q::symbol()),
+        }
+    }
+}
+
+#[cfg(feature = "defmt")]
+mod defmt_impl {
+    use super::*;
+    use defmt::{write, Format, Formatter};
+
+    impl<Q: Quantity<u8>> Format for Fmt<u8, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<u16>> Format for Fmt<u16, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<u32>> Format for Fmt<u32, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<u64>> Format for Fmt<u64, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<u128>> Format for Fmt<u128, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<usize>> Format for Fmt<usize, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<i8>> Format for Fmt<i8, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<i16>> Format for Fmt<i16, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<i32>> Format for Fmt<i32, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<i64>> Format for Fmt<i64, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<i128>> Format for Fmt<i128, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<isize>> Format for Fmt<isize, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<f32>> Format for Fmt<f32, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+
+    impl<Q: Quantity<f64>> Format for Fmt<f64, Q> {
+        fn format(&self, fmt: Formatter) {
+            write!(fmt, "{} {}", self.quantity.value(), Q::symbol());
+        }
+    }
+}