On Thu, 09 Jan 2025 11:54:57 +0100
Andreas Hindborg <a.hindborg@xxxxxxxxxx> wrote:
> Implement `strip_prefix` for `BStr` by deferring to `slice::strip_prefix`
> on the underlying `&[u8]`.
>
> Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxx>
Reviewed-by: Gary Guo <gary@xxxxxxxxxxx>
>
> ---
>
> 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 c441acf76ebd1f14919b6d233edffbbbbf944619..9c446ff1ad7adba7ca09a5ae9df00fd369a32899 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: &Self) -> Option<&BStr> {
> + self.deref()
> + .strip_prefix(pattern.deref())
> + .map(Self::from_bytes)
> + }
> }
>
> impl fmt::Display for BStr {
>
