| // Copyright 2024 The Pigweed Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| // use this file except in compliance with the License. You may obtain a copy of |
| // the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| // License for the specific language governing permissions and limitations under |
| // the License. |
| #![no_std] |
| //! Core support code for code generated by `pw_format` macros |
| //! |
| //! The contents of this crate are primarily used by code which is generated |
| //! by macros using `pw_format`. |
| |
| /// Trait used to produce printf style format strings for untyped format |
| /// specifiers. |
| /// |
| /// The const [`PrintfFormatter::FORMAT_ARG`] is used to provide the printf |
| /// format specifier (i.e. the `d` in `%02d`) for a given type in Rust. This |
| /// must be const so that it can be used to build static const format strings at |
| /// compile time. |
| pub trait PrintfFormatter { |
| /// The format specifier for this type. |
| const FORMAT_ARG: &'static str; |
| } |
| |
| /// A helper to declare a [`PrintfFormatter`] trait for a given type. |
| macro_rules! declare_formatter { |
| ($ty:ty, $specifier:literal) => { |
| impl PrintfFormatter for $ty { |
| const FORMAT_ARG: &'static str = $specifier; |
| } |
| }; |
| } |
| |
| declare_formatter!(i32, "d"); |
| declare_formatter!(u32, "u"); |
| declare_formatter!(&str, "s"); |