diff options
Diffstat (limited to 'library/core/src/num/mod.rs')
| -rw-r--r-- | library/core/src/num/mod.rs | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs index ecc1c7bf902..a82b2aa61ce 100644 --- a/library/core/src/num/mod.rs +++ b/library/core/src/num/mod.rs @@ -492,6 +492,26 @@ impl u8 { ascii::Char::from_u8(*self) } + /// Converts this byte to an [ASCII character](ascii::Char), without + /// checking whether or not it's valid. + /// + /// # Safety + /// + /// This byte must be valid ASCII, or else this is UB. + #[must_use] + #[unstable(feature = "ascii_char", issue = "110998")] + #[inline] + pub const unsafe fn as_ascii_unchecked(&self) -> ascii::Char { + assert_unsafe_precondition!( + check_library_ub, + "as_ascii_unchecked requires that the byte is valid ASCII", + (it: &u8 = self) => it.is_ascii() + ); + + // SAFETY: the caller promised that this byte is ASCII. + unsafe { ascii::Char::from_u8_unchecked(*self) } + } + /// Makes a copy of the value in its ASCII upper case equivalent. /// /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', |