diff options
| -rw-r--r-- | library/core/src/num/uint_macros.rs | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs index dba51b4f67e..e6bdc4d450d 100644 --- a/library/core/src/num/uint_macros.rs +++ b/library/core/src/num/uint_macros.rs @@ -765,6 +765,67 @@ macro_rules! uint_impl { } } + #[doc = concat!( + "Checked integer subtraction. Computes `self - rhs` and checks if the result fits into an [`", + stringify!($SignedT), "`], returning `None` if overflow occurred." + )] + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(unsigned_signed_diff)] + #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_signed_diff(2), Some(8));")] + #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_signed_diff(10), Some(-8));")] + #[doc = concat!( + "assert_eq!(", + stringify!($SelfT), + "::MAX.checked_signed_diff(", + stringify!($SignedT), + "::MAX as ", + stringify!($SelfT), + "), None);" + )] + #[doc = concat!( + "assert_eq!((", + stringify!($SignedT), + "::MAX as ", + stringify!($SelfT), + ").checked_signed_diff(", + stringify!($SelfT), + "::MAX), Some(", + stringify!($SignedT), + "::MIN));" + )] + #[doc = concat!( + "assert_eq!((", + stringify!($SignedT), + "::MAX as ", + stringify!($SelfT), + " + 1).checked_signed_diff(0), None);" + )] + #[doc = concat!( + "assert_eq!(", + stringify!($SelfT), + "::MAX.checked_signed_diff(", + stringify!($SelfT), + "::MAX), Some(0));" + )] + /// ``` + #[unstable(feature = "unsigned_signed_diff", issue = "126041")] + #[inline] + pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> { + let res = self.wrapping_sub(rhs) as $SignedT; + let overflow = (self >= rhs) == (res < 0); + + if !overflow { + Some(res) + } else { + None + } + } + /// Checked integer multiplication. Computes `self * rhs`, returning /// `None` if overflow occurred. /// |