[PATCH v1 15/28] rust: str: add `b_str!` macro

Miguel Ojeda
2022-11-10T16:44:09Z

From: Gary Guo <gary@garyguo.net>

Add the `b_str!` macro, which creates a new `BStr` from
a string literal.

It is usable in const contexts, for instance:

const X: &BStr = b_str!("Example");

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 | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index 3aa1a0cb9bf8..95eb757c619d 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -9,6 +9,27 @@ use core::fmt;
/// `BStr` is simply an alias to `[u8]`, but has a more evident semantical meaning.
pub type BStr = [u8];

+/// Creates a new [`BStr`] from a string literal.
+///
+/// `b_str!` converts the supplied string literal to byte string, so non-ASCII
+/// characters can be included.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::b_str;
+/// # use kernel::str::BStr;
+/// const MY_BSTR: &BStr = b_str!("My awesome BStr!");
+/// ```
+#[macro_export]
+macro_rules! b_str {
+ ($str:literal) => {{
+ const S: &'static str = $str;
+ const C: &'static $crate::str::BStr = S.as_bytes();
+ C
+ }};
+}
+
/// Allows formatting of [`fmt::Arguments`] into a raw buffer.
///
/// It does not fail if callers write past the end of the buffer so that they can calculate the
--
2.38.1