diff options
| -rw-r--r-- | library/core/src/fmt/num.rs | 12 | ||||
| -rw-r--r-- | library/core/src/mem/maybe_uninit.rs | 4 |
2 files changed, 11 insertions, 5 deletions
diff --git a/library/core/src/fmt/num.rs b/library/core/src/fmt/num.rs index 795cbf5fbbd..7a98210995e 100644 --- a/library/core/src/fmt/num.rs +++ b/library/core/src/fmt/num.rs @@ -595,7 +595,6 @@ fn fmt_u128(n: u128, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::R // 2^128 is about 3*10^38, so 39 gives an extra byte of space let mut buf = [MaybeUninit::<u8>::uninit(); 39]; let mut curr = buf.len() as isize; - let buf_ptr = MaybeUninit::slice_as_mut_ptr(&mut buf); let (n, rem) = udiv_1e19(n); parse_u64_into(rem, &mut buf, &mut curr); @@ -606,7 +605,11 @@ fn fmt_u128(n: u128, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::R // SAFETY: Guaranteed that we wrote at most 19 bytes, and there must be space // remaining since it has length 39 unsafe { - ptr::write_bytes(buf_ptr.offset(target), b'0', (curr - target) as usize); + ptr::write_bytes( + MaybeUninit::slice_as_mut_ptr(&mut buf).offset(target), + b'0', + (curr - target) as usize, + ); } curr = target; @@ -615,6 +618,9 @@ fn fmt_u128(n: u128, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::R // Should this following branch be annotated with unlikely? if n != 0 { let target = (buf.len() - 38) as isize; + // The raw `buf_ptr` pointer is only valid until `buf` is used the next time, + // buf `buf` is not used in this scope so we are good. + let buf_ptr = MaybeUninit::slice_as_mut_ptr(&mut buf); // SAFETY: At this point we wrote at most 38 bytes, pad up to that point, // There can only be at most 1 digit remaining. unsafe { @@ -629,7 +635,7 @@ fn fmt_u128(n: u128, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::R // UTF-8 since `DEC_DIGITS_LUT` is let buf_slice = unsafe { str::from_utf8_unchecked(slice::from_raw_parts( - buf_ptr.offset(curr), + MaybeUninit::slice_as_mut_ptr(&mut buf).offset(curr), buf.len() - curr as usize, )) }; diff --git a/library/core/src/mem/maybe_uninit.rs b/library/core/src/mem/maybe_uninit.rs index 862c452a434..660b7db70be 100644 --- a/library/core/src/mem/maybe_uninit.rs +++ b/library/core/src/mem/maybe_uninit.rs @@ -842,13 +842,13 @@ impl<T> MaybeUninit<T> { #[unstable(feature = "maybe_uninit_slice", issue = "63569")] #[inline(always)] pub fn slice_as_ptr(this: &[MaybeUninit<T>]) -> *const T { - this as *const [MaybeUninit<T>] as *const T + this.as_ptr() as *const T } /// Gets a mutable pointer to the first element of the array. #[unstable(feature = "maybe_uninit_slice", issue = "63569")] #[inline(always)] pub fn slice_as_mut_ptr(this: &mut [MaybeUninit<T>]) -> *mut T { - this as *mut [MaybeUninit<T>] as *mut T + this.as_mut_ptr() as *mut T } } |