Messages in this thread Patch in this message | | | From | Miguel Ojeda <> | Subject | [PATCH v1 19/28] rust: str: add `c_str!` macro | Date | Thu, 10 Nov 2022 17:41:31 +0100 |
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From: Gary Guo <gary@garyguo.net>
Add `c_str!`, which is a convenience macro that creates a new `CStr` from a string literal.
It is designed to be similar to a `str` in usage, and it is usable in const contexts, for instance:
const X: &CStr = c_str!("Example");
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Gary Guo <gary@garyguo.net> [Reworded, adapted for upstream and applied latest changes] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> --- rust/kernel/str.rs | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index 3ed685cb5a3c..3fb73b888dce 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -128,6 +128,18 @@ impl CStr { Ok(unsafe { Self::from_bytes_with_nul_unchecked(bytes) }) } + /// Creates a [`CStr`] from a `[u8]`, panic if input is not valid. + /// + /// This function is only meant to be used by `c_str!` macro, so + /// crates using `c_str!` macro don't have to enable `const_panic` feature. + #[doc(hidden)] + pub const fn from_bytes_with_nul_unwrap(bytes: &[u8]) -> &Self { + match Self::from_bytes_with_nul(bytes) { + Ok(v) => v, + Err(_) => panic!("string contains interior NUL"), + } + } + /// Creates a [`CStr`] from a `[u8]` without performing any additional /// checks. /// @@ -321,6 +333,26 @@ where } } +/// Creates a new [`CStr`] from a string literal. +/// +/// The string literal should not contain any `NUL` bytes. +/// +/// # Examples +/// +/// ``` +/// # use kernel::c_str; +/// # use kernel::str::CStr; +/// const MY_CSTR: &CStr = c_str!("My awesome CStr!"); +/// ``` +#[macro_export] +macro_rules! c_str { + ($str:expr) => {{ + const S: &str = concat!($str, "\0"); + const C: &$crate::str::CStr = $crate::str::CStr::from_bytes_with_nul_unwrap(S.as_bytes()); + C + }}; +} + #[cfg(test)] mod tests { use super::*; -- 2.38.1
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