From 6979bb40f8dd1a67e7508779873e7525441de0ce Mon Sep 17 00:00:00 2001 From: Iago-lito Date: Thu, 15 Apr 2021 12:31:32 +0200 Subject: [PATCH] NonZero unchecked_mul. --- library/core/src/num/nonzero.rs | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs index 7a1b4d6c719b..fdb874bc723d 100644 --- a/library/core/src/num/nonzero.rs +++ b/library/core/src/num/nonzero.rs @@ -709,6 +709,34 @@ macro_rules! nonzero_unsigned_signed_operations { // so the result cannot be zero. unsafe { $Ty::new_unchecked(self.get().saturating_mul(other.get())) } } + + /// Multiply two non-zero integers together, + /// assuming overflow cannot occur. + /// This results in undefined behavior when + #[doc = concat!("`self * rhs > ", stringify!($Int), "::MAX`, ")] + #[doc = concat!("or `self * rhs < ", stringify!($Int), "::MIN`.")] + /// + /// # Examples + /// + /// ``` + /// #![feature(nonzero_ops)] + /// # #![feature(try_trait)] + #[doc = concat!("# use std::num::", stringify!($Ty), ";")] + /// + /// # fn main() -> Result<(), std::option::NoneError> { + #[doc = concat!("let two = ", stringify!($Ty), "::new(2)?;")] + #[doc = concat!("let four = ", stringify!($Ty), "::new(4)?;")] + /// + /// assert_eq!(four, unsafe { two.unchecked_mul(two) }); + /// # Ok(()) + /// # } + /// ``` + #[unstable(feature = "nonzero_ops", issue = "84186")] + #[inline] + pub unsafe fn unchecked_mul(self, other: $Ty) -> $Ty { + // SAFETY: The caller ensures there is no overflow. + unsafe { $Ty::new_unchecked(self.get().unchecked_mul(other.get())) } + } } )+ }