add Expected trait to utils; use (already transitive) num-traits.

Signed-off-by: Jason Volk <jason@zemos.net>

Cargo.lock

@@ -730,6 +730,7 @@ dependencies = [
  "libloading",
  "log",
  "nix",
+ "num-traits",
  "rand",
  "regex",
  "reqwest",

Cargo.toml

@@ -501,6 +501,9 @@ version = "0.8.1"
 [workspace.dependencies.libc]
 version = "0.2"
 
+[workspace.dependencies.num-traits]
+version = "0.2"
+
 #
 # Patches
 #

src/core/Cargo.toml

@@ -77,6 +77,7 @@ itertools.workspace = true
 libc.workspace = true
 libloading.workspace = true
 log.workspace = true
+num-traits.workspace = true
 rand.workspace = true
 regex.workspace = true
 reqwest.workspace = true

src/core/utils/math.rs

@@ -1,7 +1,10 @@
+mod expected;
+
 use std::{cmp, convert::TryFrom};
 
 pub use checked_ops::checked_ops;
 
+pub use self::expected::Expected;
 use crate::{debug::type_name, err, Err, Error, Result};
 
 /// Checked arithmetic expression. Returns a Result<R, Error::Arithmetic>

src/core/utils/math/expected.rs

@@ -0,0 +1,52 @@
+use num_traits::ops::checked::{CheckedAdd, CheckedDiv, CheckedMul, CheckedRem, CheckedSub};
+
+use crate::expected;
+
+pub trait Expected {
+	#[inline]
+	#[must_use]
+	fn expected_add(self, rhs: Self) -> Self
+	where
+		Self: CheckedAdd + Sized,
+	{
+		expected!(self + rhs)
+	}
+
+	#[inline]
+	#[must_use]
+	fn expected_sub(self, rhs: Self) -> Self
+	where
+		Self: CheckedSub + Sized,
+	{
+		expected!(self - rhs)
+	}
+
+	#[inline]
+	#[must_use]
+	fn expected_mul(self, rhs: Self) -> Self
+	where
+		Self: CheckedMul + Sized,
+	{
+		expected!(self * rhs)
+	}
+
+	#[inline]
+	#[must_use]
+	fn expected_div(self, rhs: Self) -> Self
+	where
+		Self: CheckedDiv + Sized,
+	{
+		expected!(self / rhs)
+	}
+
+	#[inline]
+	#[must_use]
+	fn expected_rem(self, rhs: Self) -> Self
+	where
+		Self: CheckedRem + Sized,
+	{
+		expected!(self % rhs)
+	}
+}
+
+impl<T> Expected for T {}