diff options
| -rw-r--r-- | library/core/src/num/nonzero.rs | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs index 532a09736a7..d8e3c95cc87 100644 --- a/library/core/src/num/nonzero.rs +++ b/library/core/src/num/nonzero.rs @@ -721,6 +721,160 @@ macro_rules! nonzero_signed_operations { // SAFETY: absolute value of nonzero cannot yield zero values. unsafe { $Uty::new_unchecked(self.get().unsigned_abs()) } } + + /// Returns `true` if `self` is negative and `false` if the + /// number is positive. + /// + /// # Example + /// + /// ``` + /// #![feature(nonzero_negation_ops)] + /// + #[doc = concat!("# use std::num::", stringify!($Ty), ";")] + /// # fn main() { test().unwrap(); } + /// # fn test() -> Option<()> { + #[doc = concat!("let pos_five = ", stringify!($Ty), "::new(5)?;")] + #[doc = concat!("let neg_five = ", stringify!($Ty), "::new(-5)?;")] + /// + /// assert!(neg_five.is_negative()); + /// assert!(!pos_five.is_negative()); + /// # Some(()) + /// # } + /// ``` + #[must_use] + #[inline(always)] + #[unstable(feature = "nonzero_negation_ops", issue = "none")] + pub const fn is_negative(self) -> bool { + self.get().is_negative() + } + + /// Checked negation. Computes `-self`, returning `None` if `self == i32::MIN`. + /// + /// # Example + /// + /// ``` + /// #![feature(nonzero_negation_ops)] + /// + #[doc = concat!("# use std::num::", stringify!($Ty), ";")] + /// # fn main() { test().unwrap(); } + /// # fn test() -> Option<()> { + #[doc = concat!("let pos_five = ", stringify!($Ty), "::new(5)?;")] + #[doc = concat!("let neg_five = ", stringify!($Ty), "::new(-5)?;")] + #[doc = concat!("let min = ", stringify!($Ty), "::new(", + stringify!($Int), "::MIN)?;")] + /// + /// assert_eq!(pos_five.checked_neg(), Some(neg_five)); + /// assert_eq!(min.checked_neg(), None); + /// # Some(()) + /// # } + /// ``` + #[inline] + #[unstable(feature = "nonzero_negation_ops", issue = "none")] + pub const fn checked_neg(self) -> Option<$Ty> { + if let Some(result) = self.get().checked_neg() { + // SAFETY: negation of nonzero cannot yield zero values. + return Some(unsafe { $Ty::new_unchecked(result) }); + } + None + } + + /// Negates self, overflowing if this is equal to the minimum value. + /// + #[doc = concat!("See [`", stringify!($Int), "::overflowing_neg`]")] + /// for documentation on overflow behaviour. + /// + /// # Example + /// + /// ``` + /// #![feature(nonzero_negation_ops)] + /// + #[doc = concat!("# use std::num::", stringify!($Ty), ";")] + /// # fn main() { test().unwrap(); } + /// # fn test() -> Option<()> { + #[doc = concat!("let pos_five = ", stringify!($Ty), "::new(5)?;")] + #[doc = concat!("let neg_five = ", stringify!($Ty), "::new(-5)?;")] + #[doc = concat!("let min = ", stringify!($Ty), "::new(", + stringify!($Int), "::MIN)?;")] + /// + /// assert_eq!(pos_five.overflowing_neg(), (neg_five, false)); + /// assert_eq!(min.overflowing_neg(), (min, true)); + /// # Some(()) + /// # } + /// ``` + #[inline] + #[unstable(feature = "nonzero_negation_ops", issue = "none")] + pub const fn overflowing_neg(self) -> ($Ty, bool) { + let (result, overflow) = self.get().overflowing_neg(); + // SAFETY: negation of nonzero cannot yield zero values. + ((unsafe { $Ty::new_unchecked(result) }), overflow) + } + + /// Saturating negation. Computes `-self`, returning `MAX` if + /// `self == i32::MIN` instead of overflowing. + /// + /// # Example + /// + /// ``` + /// #![feature(nonzero_negation_ops)] + /// + #[doc = concat!("# use std::num::", stringify!($Ty), ";")] + /// # fn main() { test().unwrap(); } + /// # fn test() -> Option<()> { + #[doc = concat!("let pos_five = ", stringify!($Ty), "::new(5)?;")] + #[doc = concat!("let neg_five = ", stringify!($Ty), "::new(-5)?;")] + #[doc = concat!("let min = ", stringify!($Ty), "::new(", + stringify!($Int), "::MIN)?;")] + #[doc = concat!("let min_plus_one = ", stringify!($Ty), "::new(", + stringify!($Int), "::MIN + 1)?;")] + #[doc = concat!("let max = ", stringify!($Ty), "::new(", + stringify!($Int), "::MAX)?;")] + /// + /// assert_eq!(pos_five.saturating_neg(), neg_five); + /// assert_eq!(min.saturating_neg(), max); + /// assert_eq!(max.saturating_neg(), min_plus_one); + /// # Some(()) + /// # } + /// ``` + #[inline] + #[unstable(feature = "nonzero_negation_ops", issue = "none")] + pub const fn saturating_neg(self) -> $Ty { + if let Some(result) = self.checked_neg() { + return result; + } + $Ty::MAX + } + + /// Wrapping (modular) negation. Computes `-self`, wrapping around at the boundary + /// of the type. + /// + #[doc = concat!("See [`", stringify!($Int), "::wrapping_neg`]")] + /// for documentation on overflow behaviour. + /// + /// # Example + /// + /// ``` + /// #![feature(nonzero_negation_ops)] + /// + #[doc = concat!("# use std::num::", stringify!($Ty), ";")] + /// # fn main() { test().unwrap(); } + /// # fn test() -> Option<()> { + #[doc = concat!("let pos_five = ", stringify!($Ty), "::new(5)?;")] + #[doc = concat!("let neg_five = ", stringify!($Ty), "::new(-5)?;")] + #[doc = concat!("let min = ", stringify!($Ty), "::new(", + stringify!($Int), "::MIN)?;")] + /// + /// assert_eq!(pos_five.wrapping_neg(), neg_five); + /// assert_eq!(min.wrapping_neg(), min); + /// # Some(()) + /// # } + /// ``` + #[inline] + #[unstable(feature = "nonzero_negation_ops", issue = "none")] + pub const fn wrapping_neg(self) -> $Ty { + let result = self.get().wrapping_neg(); + // SAFETY: negation of nonzero cannot yield zero values. + unsafe { $Ty::new_unchecked(result) } + } } )+ } |