diff options
| -rw-r--r-- | library/core/src/num/uint_macros.rs | 24 | ||||
| -rw-r--r-- | library/coretests/tests/lib.rs | 1 | ||||
| -rw-r--r-- | library/coretests/tests/num/uint_macros.rs | 8 |
3 files changed, 33 insertions, 0 deletions
diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs index 5f82e6af86b..4ee0e7326b3 100644 --- a/library/core/src/num/uint_macros.rs +++ b/library/core/src/num/uint_macros.rs @@ -213,6 +213,30 @@ macro_rules! uint_impl { (!self).trailing_zeros() } + /// Returns the minimum number of bits required to represent `self`. + /// + /// This method returns zero if `self` is zero. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(uint_bit_width)] + /// + #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".bit_width(), 0);")] + #[doc = concat!("assert_eq!(0b111_", stringify!($SelfT), ".bit_width(), 3);")] + #[doc = concat!("assert_eq!(0b1110_", stringify!($SelfT), ".bit_width(), 4);")] + #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.bit_width(), ", stringify!($BITS), ");")] + /// ``` + #[unstable(feature = "uint_bit_width", issue = "142326")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline(always)] + pub const fn bit_width(self) -> u32 { + Self::BITS - self.leading_zeros() + } + /// Returns `self` with only the most significant bit set, or `0` if /// the input is `0`. /// diff --git a/library/coretests/tests/lib.rs b/library/coretests/tests/lib.rs index 92b920dd775..5449132413b 100644 --- a/library/coretests/tests/lib.rs +++ b/library/coretests/tests/lib.rs @@ -94,6 +94,7 @@ #![feature(try_blocks)] #![feature(try_find)] #![feature(try_trait_v2)] +#![feature(uint_bit_width)] #![feature(unsize)] #![feature(unwrap_infallible)] // tidy-alphabetical-end diff --git a/library/coretests/tests/num/uint_macros.rs b/library/coretests/tests/num/uint_macros.rs index 6f3d160964f..7e02027bdd6 100644 --- a/library/coretests/tests/num/uint_macros.rs +++ b/library/coretests/tests/num/uint_macros.rs @@ -72,6 +72,14 @@ macro_rules! uint_module { assert_eq_const_safe!(u32: X.trailing_ones(), 0); } + fn test_bit_width() { + assert_eq_const_safe!(u32: A.bit_width(), 6); + assert_eq_const_safe!(u32: B.bit_width(), 6); + assert_eq_const_safe!(u32: C.bit_width(), 7); + assert_eq_const_safe!(u32: _0.bit_width(), 0); + assert_eq_const_safe!(u32: _1.bit_width(), $T::BITS); + } + fn test_rotate() { assert_eq_const_safe!($T: A.rotate_left(6).rotate_right(2).rotate_right(4), A); assert_eq_const_safe!($T: B.rotate_left(3).rotate_left(2).rotate_right(5), B); |