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Document unsafety in src/libcore/hash/mod.rs

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This commit is contained in:
LeSeulArtichaut 2020-04-11 22:00:34 +02:00
parent 37514dedab
commit d1ce7ff84e
1 changed files with 7 additions and 2 deletions
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9
src/libcore/hash/mod.rs
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@ -79,8 +79,6 @@
//! }
//! ```
// ignore-tidy-undocumented-unsafe
#![stable(feature = "rust1", since = "1.0.0")]
use crate::fmt;
@ -572,6 +570,9 @@ mod impls {
fn hash_slice<H: Hasher>(data: &[$ty], state: &mut H) {
let newlen = data.len() * mem::size_of::<$ty>();
let ptr = data.as_ptr() as *const u8;
// SAFETY: `ptr` is valid and aligned, the new slice only spans
// across `data` and is never mutated, and its total size is the
// same as the original `data` so it can't be over `isize::MAX`.
state.write(unsafe { slice::from_raw_parts(ptr, newlen) })
}
}
@ -691,6 +692,8 @@ mod impls {
state.write_usize(*self as *const () as usize);
} else {
// Fat pointer
// SAFETY: we are accessing the memory occupied by `self`
// which is guaranteed to be valid.
let (a, b) = unsafe { *(self as *const Self as *const (usize, usize)) };
state.write_usize(a);
state.write_usize(b);
@ -706,6 +709,8 @@ mod impls {
state.write_usize(*self as *const () as usize);
} else {
// Fat pointer
// SAFETY: we are accessing the memory occupied by `self`
// which is guaranteed to be valid.
let (a, b) = unsafe { *(self as *const Self as *const (usize, usize)) };
state.write_usize(a);
state.write_usize(b);