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Message-ID: <04049a83-c757-4103-9d63-f303686d8dbf@redhat.com>
Date: Tue, 13 Feb 2024 15:12:24 +0100
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Subject: Re: [PATCH v2] rust: str: add {make,to}_{upper,lower}case() to
 CString
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To: ojeda@kernel.org, alex.gaynor@gmail.com, wedsonaf@gmail.com,
 boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com,
 benno.lossin@proton.me, a.hindborg@samsung.com, aliceryhl@google.com
Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240130023843.11512-1-dakr@redhat.com>
From: Danilo Krummrich <dakr@redhat.com>
Organization: RedHat
In-Reply-To: <20240130023843.11512-1-dakr@redhat.com>
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On 1/30/24 03:35, Danilo Krummrich wrote:
> Add functions to convert a CString to upper- / lowercase, either
> in-place or by creating a copy of the original CString.
> 
> Naming followes the one from the Rust stdlib, where functions starting
> with 'to' create a copy and functions starting with 'make' perform an
> in-place conversion.
> 
> This is required by the Nova project (GSP only Rust successor of
> Nouveau) to convert stringified enum values (representing different GPU
> chipsets) to strings in order to generate the corresponding firmware
> paths. See also [1].
> 
> [1] https://rust-for-linux.zulipchat.com/#narrow/stream/288089-General/topic/String.20manipulation.20in.20kernel.20Rust
> 
> Signed-off-by: Danilo Krummrich <dakr@redhat.com>

Ping.

> ---
> Changes in V2:
>    - expand commit message mentioning the use case
>    - expand function doc comments to match the ones from Rust's stdlib
>    - rename to_* to make_* and add the actual to_* implementations
> ---
>   rust/kernel/str.rs | 60 ++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 60 insertions(+)
> 
> diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
> index 7d848b83add4..758bb70d98e9 100644
> --- a/rust/kernel/str.rs
> +++ b/rust/kernel/str.rs
> @@ -581,6 +581,66 @@ pub fn try_from_fmt(args: fmt::Arguments<'_>) -> Result<Self, Error> {
>           // exist in the buffer.
>           Ok(Self { buf })
>       }
> +
> +    /// Converts this CString to its ASCII lower case equivalent in-place.
> +    ///
> +    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
> +    /// but non-ASCII letters are unchanged.
> +    ///
> +    /// To return a new lowercased value without modifying the existing one, use
> +    /// [`to_ascii_lowercase()`].
> +    ///
> +    /// [`to_ascii_lowercase()`]: #method.to_ascii_lowercase
> +    pub fn make_ascii_lowercase(&mut self) {
> +        self.buf.make_ascii_lowercase();
> +    }
> +
> +    /// Converts this CString to its ASCII upper case equivalent in-place.
> +    ///
> +    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
> +    /// but non-ASCII letters are unchanged.
> +    ///
> +    /// To return a new uppercased value without modifying the existing one, use
> +    /// [`to_ascii_uppercase()`].
> +    ///
> +    /// [`to_ascii_uppercase()`]: #method.to_ascii_uppercase
> +    pub fn make_ascii_uppercase(&mut self) {
> +        self.buf.make_ascii_uppercase();
> +    }
> +
> +    /// Returns a copy of this CString where each character is mapped to its
> +    /// ASCII lower case equivalent.
> +    ///
> +    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
> +    /// but non-ASCII letters are unchanged.
> +    ///
> +    /// To lowercase the value in-place, use [`make_ascii_lowercase`].
> +    ///
> +    /// [`make_ascii_lowercase`]: str::make_ascii_lowercase
> +    pub fn to_ascii_lowercase(&self) -> Result<CString, AllocError> {
> +        let mut s = (*self).to_cstring()?;
> +
> +        s.make_ascii_lowercase();
> +
> +        return Ok(s);
> +    }
> +
> +    /// Returns a copy of this CString where each character is mapped to its
> +    /// ASCII upper case equivalent.
> +    ///
> +    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
> +    /// but non-ASCII letters are unchanged.
> +    ///
> +    /// To uppercase the value in-place, use [`make_ascii_uppercase`].
> +    ///
> +    /// [`make_ascii_uppercase`]: str::make_ascii_uppercase
> +    pub fn to_ascii_uppercase(&self) -> Result<CString, AllocError> {
> +        let mut s = (*self).to_cstring()?;
> +
> +        s.make_ascii_uppercase();
> +
> +        return Ok(s);
> +    }
>   }
>   
>   impl Deref for CString {
> 
> base-commit: 41bccc98fb7931d63d03f326a746ac4d429c1dd3