num_traits/ops/
overflowing.rs

1use core::ops::{Add, Mul, Sub};
2#[cfg(has_i128)]
3use core::{i128, u128};
4use core::{i16, i32, i64, i8, isize};
5use core::{u16, u32, u64, u8, usize};
6
7macro_rules! overflowing_impl {
8    ($trait_name:ident, $method:ident, $t:ty) => {
9        impl $trait_name for $t {
10            #[inline]
11            fn $method(&self, v: &Self) -> (Self, bool) {
12                <$t>::$method(*self, *v)
13            }
14        }
15    };
16}
17
18/// Performs addition with a flag for overflow.
19pub trait OverflowingAdd: Sized + Add<Self, Output = Self> {
20    /// Returns a tuple of the sum along with a boolean indicating whether an arithmetic overflow would occur.
21    /// If an overflow would have occurred then the wrapped value is returned.
22    fn overflowing_add(&self, v: &Self) -> (Self, bool);
23}
24
25overflowing_impl!(OverflowingAdd, overflowing_add, u8);
26overflowing_impl!(OverflowingAdd, overflowing_add, u16);
27overflowing_impl!(OverflowingAdd, overflowing_add, u32);
28overflowing_impl!(OverflowingAdd, overflowing_add, u64);
29overflowing_impl!(OverflowingAdd, overflowing_add, usize);
30#[cfg(has_i128)]
31overflowing_impl!(OverflowingAdd, overflowing_add, u128);
32
33overflowing_impl!(OverflowingAdd, overflowing_add, i8);
34overflowing_impl!(OverflowingAdd, overflowing_add, i16);
35overflowing_impl!(OverflowingAdd, overflowing_add, i32);
36overflowing_impl!(OverflowingAdd, overflowing_add, i64);
37overflowing_impl!(OverflowingAdd, overflowing_add, isize);
38#[cfg(has_i128)]
39overflowing_impl!(OverflowingAdd, overflowing_add, i128);
40
41/// Performs substraction with a flag for overflow.
42pub trait OverflowingSub: Sized + Sub<Self, Output = Self> {
43    /// Returns a tuple of the difference along with a boolean indicating whether an arithmetic overflow would occur.
44    /// If an overflow would have occurred then the wrapped value is returned.
45    fn overflowing_sub(&self, v: &Self) -> (Self, bool);
46}
47
48overflowing_impl!(OverflowingSub, overflowing_sub, u8);
49overflowing_impl!(OverflowingSub, overflowing_sub, u16);
50overflowing_impl!(OverflowingSub, overflowing_sub, u32);
51overflowing_impl!(OverflowingSub, overflowing_sub, u64);
52overflowing_impl!(OverflowingSub, overflowing_sub, usize);
53#[cfg(has_i128)]
54overflowing_impl!(OverflowingSub, overflowing_sub, u128);
55
56overflowing_impl!(OverflowingSub, overflowing_sub, i8);
57overflowing_impl!(OverflowingSub, overflowing_sub, i16);
58overflowing_impl!(OverflowingSub, overflowing_sub, i32);
59overflowing_impl!(OverflowingSub, overflowing_sub, i64);
60overflowing_impl!(OverflowingSub, overflowing_sub, isize);
61#[cfg(has_i128)]
62overflowing_impl!(OverflowingSub, overflowing_sub, i128);
63
64/// Performs multiplication with a flag for overflow.
65pub trait OverflowingMul: Sized + Mul<Self, Output = Self> {
66    /// Returns a tuple of the product along with a boolean indicating whether an arithmetic overflow would occur.
67    /// If an overflow would have occurred then the wrapped value is returned.
68    fn overflowing_mul(&self, v: &Self) -> (Self, bool);
69}
70
71overflowing_impl!(OverflowingMul, overflowing_mul, u8);
72overflowing_impl!(OverflowingMul, overflowing_mul, u16);
73overflowing_impl!(OverflowingMul, overflowing_mul, u32);
74overflowing_impl!(OverflowingMul, overflowing_mul, u64);
75overflowing_impl!(OverflowingMul, overflowing_mul, usize);
76#[cfg(has_i128)]
77overflowing_impl!(OverflowingMul, overflowing_mul, u128);
78
79overflowing_impl!(OverflowingMul, overflowing_mul, i8);
80overflowing_impl!(OverflowingMul, overflowing_mul, i16);
81overflowing_impl!(OverflowingMul, overflowing_mul, i32);
82overflowing_impl!(OverflowingMul, overflowing_mul, i64);
83overflowing_impl!(OverflowingMul, overflowing_mul, isize);
84#[cfg(has_i128)]
85overflowing_impl!(OverflowingMul, overflowing_mul, i128);
86
87#[test]
88fn test_overflowing_traits() {
89    fn overflowing_add<T: OverflowingAdd>(a: T, b: T) -> (T, bool) {
90        a.overflowing_add(&b)
91    }
92    fn overflowing_sub<T: OverflowingSub>(a: T, b: T) -> (T, bool) {
93        a.overflowing_sub(&b)
94    }
95    fn overflowing_mul<T: OverflowingMul>(a: T, b: T) -> (T, bool) {
96        a.overflowing_mul(&b)
97    }
98    assert_eq!(overflowing_add(5i16, 2), (7, false));
99    assert_eq!(overflowing_add(i16::MAX, 1), (i16::MIN, true));
100    assert_eq!(overflowing_sub(5i16, 2), (3, false));
101    assert_eq!(overflowing_sub(i16::MIN, 1), (i16::MAX, true));
102    assert_eq!(overflowing_mul(5i16, 2), (10, false));
103    assert_eq!(overflowing_mul(1_000_000_000i32, 10), (1410065408, true));
104}
num_traits/ops/overflowing.rs

num_traits/ops/
overflowing.rs
