| commit | 11612a423fa0571718636f08ca28304ed1c12021 | [log] [tgz] |
|---|---|---|
| author | Android Build Coastguard Worker <[email protected]> | Thu Aug 25 07:54:00 2022 +0000 |
| committer | Android Build Coastguard Worker <[email protected]> | Thu Aug 25 07:54:00 2022 +0000 |
| tree | fbd0d683b85a5b7f16cebc8ebf609887df552ed1 | |
| parent | 5eeb50be3f3632e1368110d6adf2e9fb77b31533 [diff] | |
| parent | 41f53a7b2311ba3bfece38a5ae473912cf7b5312 [diff] |
Snap for 8992082 from 41f53a7b2311ba3bfece38a5ae473912cf7b5312 to gki13-boot-release Change-Id: I2ea2c75b831777cf23a2aa16d54917f374ec2f3f
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.
use memoffset::{offset_of, span_of}; #[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_refs_to_cell)]