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The checked Rust arithmetic methods are unfortunately not behind a trait, which makes them unavailable to generic code. As a start, add the `CheckedAdd` trait providing the `checked_add` operation and implement it for all integer types. Its name and location are inspired by the user-space `num` crate. This trait is to be first used by the `Alignment` type. Signed-off-by: Alexandre Courbot Reviewed-by: Daniel Almeida --- rust/kernel/lib.rs | 1 + rust/kernel/num.rs | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 6b4774b2b1c37f4da1866e993be6230bc6715841..2955f65da1278dd4cba1e4272ff= 178b8211a892c 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -89,6 +89,7 @@ pub mod mm; #[cfg(CONFIG_NET)] pub mod net; +pub mod num; pub mod of; #[cfg(CONFIG_PM_OPP)] pub mod opp; diff --git a/rust/kernel/num.rs b/rust/kernel/num.rs new file mode 100644 index 0000000000000000000000000000000000000000..c81bb046078b70c321dd52aa9c2= b5518be49d249 --- /dev/null +++ b/rust/kernel/num.rs @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Numerical and binary utilities for primitive types. + +use core::ops::Add; + +/// Trait for performing a checked addition that returns `None` if the ope= ration would overflow. +/// +/// This trait exists in order to represent scalar types already having a = `checked_add` method in +/// generic code. +pub trait CheckedAdd: Sized + Add { + /// Computes `self + rhs`, returning `None` if an overflow would occur. + fn checked_add(self, rhs: Self) -> Option; +} + +macro_rules! impl_checked_add { + ($($t:ty),*) =3D> { + $( + impl CheckedAdd for $t { + fn checked_add(self, rhs: Self) -> Option { + self.checked_add(rhs) + } + } + )* + }; +} + +impl_checked_add!(u8, u16, u32, u64, usize, i8, i16, i32, i64, isize); --=20 2.50.1