Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Make sure we do not create an unaligned slice #42

Merged
merged 2 commits into from
Aug 3, 2018
Merged

Make sure we do not create an unaligned slice #42

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f25840a
Make sure we do not create an unaligned slice
RalfJung Aug 2, 2018
9fd343b
assert that the mid slice is aligned
RalfJung Aug 3, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 6 additions & 1 deletion src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -178,12 +178,17 @@ fn chunk_align<Chunk: ByteChunk>(x: &[u8]) -> (&[u8], &[Chunk], &[u8]) {
let offset_ptr = (x.as_ptr() as usize) % align;
let offset_end = (x.as_ptr() as usize + x.len()) % align;

let d1 = (align - offset_ptr) % align; // `offset_ptr` might be 0, then `d1` should be 0.
let d2 = x.len().saturating_sub(offset_end);
let d1 = cmp::min((align - offset_ptr) % align, d2);
if d1 > d2 {
// No space for anything aligned
return (x, &[], &[]);
}

let (init, tail) = x.split_at(d2);
let (init, mid) = init.split_at(d1);
assert_eq!(mid.len() % align, 0);
assert_eq!(mid.as_ptr() as usize % mem::align_of::<Chunk>(), 0, "`mid` must be aligned");
let mid = unsafe { slice::from_raw_parts(mid.as_ptr() as *const Chunk, mid.len() / align) };

(init, mid, tail)
Expand Down