commit | 83cc72322d29387af97d008cf0ca92f28f53b019 | [log] [tgz] |
---|---|---|
author | Android Build Coastguard Worker <android-build-coastguard-worker@google.com> | Mon Jan 31 01:50:50 2022 +0000 |
committer | Android Build Coastguard Worker <android-build-coastguard-worker@google.com> | Mon Jan 31 01:50:50 2022 +0000 |
tree | 36bc3873a07934dd7d5791d7bcadf34d97f2e051 | |
parent | 44d9edb21054b4662cf2f70dde8b806a7603f750 [diff] | |
parent | 0b696fa0112b6ad99c0ce1b9a4026316181ce044 [diff] |
Snap for 8133678 from 0b696fa0112b6ad99c0ce1b9a4026316181ce044 to t-keystone-qcom-release Change-Id: I2fab7c76f3073f60900f60b0136a90f24367058a
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)]