| commit | db36f4b0cb980a2a76b26cd1ebff45ee0fb2ef9f | [log] [tgz] |
|---|---|---|
| author | Roopa Sattiraju <[email protected]> | Tue Dec 21 16:37:23 2021 -0800 |
| committer | Roopa Sattiraju <[email protected]> | Tue Dec 21 16:49:03 2021 -0800 |
| tree | 36bc3873a07934dd7d5791d7bcadf34d97f2e051 | |
| parent | 7efe0cdee56598f959e5e07999ed8a64c2019ad5 [diff] |
Adding bluetooth apex Bug: 206121418 Test: Compile Change-Id: Ie8bd93197f4c836b626c0bb3cdfc4d1fa0b76d47
C-Like offset_of functionality for Rust structs.
Introduces the following macros:
offset_of! for obtaining the offset of a member of a struct.offset_of_tuple! for obtaining the offset of a member of a tuple. (Requires Rust 1.20+)span_of! for obtaining the range that a field, or fields, span.memoffset works under no_std environments.
Add the following dependency to your Cargo.toml:
[dependencies] memoffset = "0.6"
These versions will compile fine with rustc versions greater or equal to 1.19.
Add the following lines at the top of your main.rs or lib.rs files.
#[macro_use] extern crate memoffset;
#[macro_use] extern crate memoffset; #[repr(C, packed)] struct Foo { a: u32, b: u32, c: [u8; 5], d: u32, } fn main() { assert_eq!(offset_of!(Foo, b), 4); assert_eq!(offset_of!(Foo, d), 4+4+5); assert_eq!(span_of!(Foo, a), 0..4); assert_eq!(span_of!(Foo, a .. c), 0..8); assert_eq!(span_of!(Foo, a ..= c), 0..13); assert_eq!(span_of!(Foo, ..= d), 0..17); assert_eq!(span_of!(Foo, b ..), 4..17); }
memoffset has experimental support for compile-time offset_of! on a nightly compiler.
In order to use it, you must enable the unstable_const crate feature and several compiler features.
Cargo.toml:
[dependencies.memoffset] version = "0.6" features = ["unstable_const"]
Your crate root: (lib.rs/main.rs)
#![feature(const_ptr_offset_from, const_maybe_uninit_as_ptr, const_raw_ptr_deref, const_refs_to_cell)]