[PATCH v7 2/6] rust: str: implement `Index` for `BStr`

Andreas Hindborg
2025-02-18T13:02:27Z

The `Index` implementation on `BStr` was lost when we switched `BStr` from
a type alias of `[u8]` to a newtype. This patch adds back `Index` by
implementing `Index` for `BStr` when `Index` would be implemented for
`[u8]`.

Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
---
rust/kernel/str.rs | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index 002dcddf7c768..ba6b1a5c4f99d 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -114,6 +114,17 @@ fn eq(&self, other: &Self) -> bool {
}
}

+impl<Idx> Index<Idx> for BStr
+where
+ [u8]: Index<Idx, Output = [u8]>,
+{
+ type Output = Self;
+
+ fn index(&self, index: Idx) -> &Self::Output {
+ BStr::from_bytes(&self.0[index])
+ }
+}
+
/// Creates a new [`BStr`] from a string literal.
///
/// `b_str!` converts the supplied string literal to byte string, so non-ASCII

--
2.47.0