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

Jump to bottom

docs: std::hash::Hash should ensure prefix-free data #89438

Merged
merged 3 commits into from
Oct 10, 2021
Merged

docs: std::hash::Hash should ensure prefix-free data #89438

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
f531b81
docs: `std::hash::Hash` should ensure prefix-free data
pierwill Oct 1, 2021
2a5dcd5
fix: edit description of "prefix-free"
pierwill Oct 1, 2021
749194d
Update library/core/src/hash/mod.rs
pierwill Oct 9, 2021
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
12 changes: 12 additions & 0 deletions library/core/src/hash/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -153,9 +153,21 @@ mod sip;
/// Thankfully, you won't need to worry about upholding this property when
/// deriving both [`Eq`] and `Hash` with `#[derive(PartialEq, Eq, Hash)]`.
///
/// ## Prefix collisions
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Thinking more about this... "Collision" isn't the right term, here, is it?

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It's not but I can't think of a better word to use.

///
/// Implementations of `hash` should ensure that the data they
/// pass to the `Hasher` are prefix-free. That is,
/// unequal values should cause two different sequences of values to be written,
/// and neither of the two sequences should be a prefix of the other.
///
/// For example, the standard implementation of [`Hash` for `&str`][impl] passes an extra
/// `0xFF` byte to the `Hasher` so that the values `("ab", "c")` and `("a",
/// "bc")` hash differently.
///
/// [`HashMap`]: ../../std/collections/struct.HashMap.html
/// [`HashSet`]: ../../std/collections/struct.HashSet.html
/// [`hash`]: Hash::hash
/// [impl]: ../../std/primitive.str.html#impl-Hash
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_diagnostic_item = "Hash"]
pub trait Hash {
Expand Down