[PATCH v7 4/6] rust: str: implement `strip_prefix` for `BStr`
STALE584d
REVIEWED: 16 (16M)
From: Andreas Hindborg <a.hindborg@kernel.org>
Date: 2025-02-18 13:01:47
Also in:
linux-kbuild, lkml, rust-for-linux
Subsystem:
rust, the rest · Maintainers:
Miguel Ojeda, Linus Torvalds
2 review trailers (2 from subsystem maintainers).
Implement `strip_prefix` for `BStr` by deferring to `slice::strip_prefix` on the underlying `&[u8]`. Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org> --- It is also possible to get this method by implementing `core::slice::SlicePattern` for `BStr`. `SlicePattern` is unstable, so this seems more reasonable. --- rust/kernel/str.rs | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index c6bd2c69543dc..db272d2198fcc 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs@@ -31,6 +31,22 @@ pub const fn from_bytes(bytes: &[u8]) -> &Self { // SAFETY: `BStr` is transparent to `[u8]`. unsafe { &*(bytes as *const [u8] as *const BStr) } } + + /// Strip a prefix from `self`. Delegates to [`slice::strip_prefix`]. + /// + /// # Example + /// ``` + /// use kernel::b_str; + /// assert_eq!(Some(b_str!("bar")), b_str!("foobar").strip_prefix(b_str!("foo"))); + /// assert_eq!(None, b_str!("foobar").strip_prefix(b_str!("bar"))); + /// assert_eq!(Some(b_str!("foobar")), b_str!("foobar").strip_prefix(b_str!(""))); + /// assert_eq!(Some(b_str!("")), b_str!("foobar").strip_prefix(b_str!("foobar"))); + /// ``` + pub fn strip_prefix(&self, pattern: impl AsRef<Self>) -> Option<&BStr> { + self.deref() + .strip_prefix(pattern.as_ref().deref()) + .map(Self::from_bytes) + } } impl fmt::Display for BStr {
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2.47.0