| Crates.io | memoffset |
| lib.rs | memoffset |
| version | 0.9.1 |
| created_at | 2017-10-17 06:16:56.082296+00 |
| updated_at | 2024-03-26 19:58:31.849513+00 |
| description | offset_of functionality for Rust structs. |
| homepage | |
| repository | https://github.com/Gilnaa/memoffset |
| max_upload_size | |
| id | 35941 |
| size | 39,352 |
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+)offset_of_union! for obtaining the offset of a member of a union.span_of! for obtaining the range that a field, or fields, span.memoffset works under no_std environments.
If you're using a rustc version greater or equal to 1.77, this crate's offset_of!() macro simply forwards to core::mem::offset_of!().
Add the following dependency to your Cargo.toml:
[dependencies]
memoffset = "0.9"
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 support for compile-time offset_of! on rust>=1.65.
On versions below 1.77, this is an incomplete implementation with one caveat:
Due to dependence on #![feature(const_refs_to_cell)], you cannot get the offset of a Cell field in a const-context.