Refactor project structure

kernel/libs/int-to-c-enum/src/lib.rs

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: MPL-2.0
+
+//! This crate provides a derive macro named TryFromInt. This macro can be used to automatically implement TryFrom trait
+//! for [C-like enums](https://doc.rust-lang.org/stable/rust-by-example/custom_types/enum/c_like.html).
+//!
+//! Currently, this macro only supports enums with [explicit discriminants](https://doc.rust-lang.org/reference/items/enumerations.html#explicit-discriminants).
+//!
+//! Below is a simple example. We derive macro `TryFromInt` for an enum `Color`.
+//! ```rust
+//! use int_to_c_enum::TryFromInt;
+//! #[repr(u8)]
+//! #[derive(TryFromInt, Eq, PartialEq)]
+//! pub enum Color {
+//!     Red = 1,
+//!     Yellow = 2,
+//!     Blue = 3,
+//! }
+//! // Then, we can use method `try_from` for `Color`.
+//! let color = Color::try_from(1).unwrap();
+//! assert!(color == Color::Red);
+//! ```
+//!
+//! The `TryFromInt` macro will automatically implement trait `TryFrom<u8>` for `Color`.
+//! After macro expansion, the generated code looks like as follows:
+//! ```ignore
+//! impl TryFrom<u8> for Color {
+//!     type Error = TryFromIntError;
+//!     fn try_from(value: u8) -> Result<Self, Self::Error> {
+//!         match value {
+//!             1 => Ok(Color::Red),
+//!             2 => Ok(Color::Yellow),
+//!             3 => Ok(Color::Blue),
+//!             _ => Err(TryFromIntError::InvalidValue),
+//!         }
+//!     }
+//! }
+//! ```
+//!
+
+#![cfg_attr(not(test), no_std)]
+
+/// Error type for TryFromInt derive macro
+#[derive(Debug, Clone, Copy)]
+pub enum TryFromIntError {
+    InvalidValue,
+}
+
+#[cfg(feature = "derive")]
+pub use int_to_c_enum_derive::TryFromInt;