overflowing.rs - source
Description: Source of the Rust file `/Users/erlendbasso/.cargo/registry/src/github.com-1ecc6299db9ec823/num-traits-0.2.15/src/ops/overflowing.rs`.
Keywords: rust, rustlang, rust-lang

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    use core::ops::{Add, Mul, Sub};
    #[cfg(has_i128)]
    use core::{i128, u128};
    use core::{i16, i32, i64, i8, isize};
    use core::{u16, u32, u64, u8, usize};

    macro_rules! overflowing_impl {
        ($trait_name:ident, $method:ident, $t:ty) => {
            impl $trait_name for $t {
                #[inline]
                fn $method(&self, v: &Self) -> (Self, bool) {
                    <$t>::$method(*self, *v)
                }
            }
        };
    }

    /// Performs addition with a flag for overflow.
    pub trait OverflowingAdd: Sized + Add<Self, Output = Self> {
        /// Returns a tuple of the sum along with a boolean indicating whether an arithmetic overflow would occur.
        /// If an overflow would have occurred then the wrapped value is returned.
        fn overflowing_add(&self, v: &Self) -> (Self, bool);
    }

    overflowing_impl!(OverflowingAdd, overflowing_add, u8);
    overflowing_impl!(OverflowingAdd, overflowing_add, u16);
    overflowing_impl!(OverflowingAdd, overflowing_add, u32);
    overflowing_impl!(OverflowingAdd, overflowing_add, u64);
    overflowing_impl!(OverflowingAdd, overflowing_add, usize);
    #[cfg(has_i128)]
    overflowing_impl!(OverflowingAdd, overflowing_add, u128);

    overflowing_impl!(OverflowingAdd, overflowing_add, i8);
    overflowing_impl!(OverflowingAdd, overflowing_add, i16);
    overflowing_impl!(OverflowingAdd, overflowing_add, i32);
    overflowing_impl!(OverflowingAdd, overflowing_add, i64);
    overflowing_impl!(OverflowingAdd, overflowing_add, isize);
    #[cfg(has_i128)]
    overflowing_impl!(OverflowingAdd, overflowing_add, i128);

    /// Performs substraction with a flag for overflow.
    pub trait OverflowingSub: Sized + Sub<Self, Output = Self> {
        /// Returns a tuple of the difference along with a boolean indicating whether an arithmetic overflow would occur.
        /// If an overflow would have occurred then the wrapped value is returned.
        fn overflowing_sub(&self, v: &Self) -> (Self, bool);
    }

    overflowing_impl!(OverflowingSub, overflowing_sub, u8);
    overflowing_impl!(OverflowingSub, overflowing_sub, u16);
    overflowing_impl!(OverflowingSub, overflowing_sub, u32);
    overflowing_impl!(OverflowingSub, overflowing_sub, u64);
    overflowing_impl!(OverflowingSub, overflowing_sub, usize);
    #[cfg(has_i128)]
    overflowing_impl!(OverflowingSub, overflowing_sub, u128);

    overflowing_impl!(OverflowingSub, overflowing_sub, i8);
    overflowing_impl!(OverflowingSub, overflowing_sub, i16);
    overflowing_impl!(OverflowingSub, overflowing_sub, i32);
    overflowing_impl!(OverflowingSub, overflowing_sub, i64);
    overflowing_impl!(OverflowingSub, overflowing_sub, isize);
    #[cfg(has_i128)]
    overflowing_impl!(OverflowingSub, overflowing_sub, i128);

    /// Performs multiplication with a flag for overflow.
    pub trait OverflowingMul: Sized + Mul<Self, Output = Self> {
        /// Returns a tuple of the product along with a boolean indicating whether an arithmetic overflow would occur.
        /// If an overflow would have occurred then the wrapped value is returned.
        fn overflowing_mul(&self, v: &Self) -> (Self, bool);
    }

    overflowing_impl!(OverflowingMul, overflowing_mul, u8);
    overflowing_impl!(OverflowingMul, overflowing_mul, u16);
    overflowing_impl!(OverflowingMul, overflowing_mul, u32);
    overflowing_impl!(OverflowingMul, overflowing_mul, u64);
    overflowing_impl!(OverflowingMul, overflowing_mul, usize);
    #[cfg(has_i128)]
    overflowing_impl!(OverflowingMul, overflowing_mul, u128);

    overflowing_impl!(OverflowingMul, overflowing_mul, i8);
    overflowing_impl!(OverflowingMul, overflowing_mul, i16);
    overflowing_impl!(OverflowingMul, overflowing_mul, i32);
    overflowing_impl!(OverflowingMul, overflowing_mul, i64);
    overflowing_impl!(OverflowingMul, overflowing_mul, isize);
    #[cfg(has_i128)]
    overflowing_impl!(OverflowingMul, overflowing_mul, i128);

    #[test]
    fn test_overflowing_traits() {
        fn overflowing_add<T: OverflowingAdd>(a: T, b: T) -> (T, bool) {
            a.overflowing_add(&b)
        }
        fn overflowing_sub<T: OverflowingSub>(a: T, b: T) -> (T, bool) {
            a.overflowing_sub(&b)
        }
        fn overflowing_mul<T: OverflowingMul>(a: T, b: T) -> (T, bool) {
            a.overflowing_mul(&b)
        }
        assert_eq!(overflowing_add(5i16, 2), (7, false));
        assert_eq!(overflowing_add(i16::MAX, 1), (i16::MIN, true));
        assert_eq!(overflowing_sub(5i16, 2), (3, false));
        assert_eq!(overflowing_sub(i16::MIN, 1), (i16::MAX, true));
        assert_eq!(overflowing_mul(5i16, 2), (10, false));
        assert_eq!(overflowing_mul(1_000_000_000i32, 10), (1410065408, true));
    }