#offset #mem #offset_of #offsetof

no-std memoffset

offset_of functionality for Rust structs

7 releases

0.5.3 Nov 7, 2019
0.5.2 Oct 31, 2019
0.5.1 Jul 15, 2019
0.4.0 Jul 4, 2019
0.1.0 Oct 17, 2017

#6 in No standard library

Download history 105323/week @ 2019-07-25 108587/week @ 2019-08-01 118512/week @ 2019-08-08 110641/week @ 2019-08-15 106160/week @ 2019-08-22 104905/week @ 2019-08-29 120145/week @ 2019-09-05 114663/week @ 2019-09-12 116300/week @ 2019-09-19 128996/week @ 2019-09-26 137534/week @ 2019-10-03 137427/week @ 2019-10-10 138224/week @ 2019-10-17 142841/week @ 2019-10-24 156566/week @ 2019-10-31

537,808 downloads per month
Used in 2,792 crates (18 directly)

MIT license

20KB
279 lines

memoffset

C-Like offset_of functionality for Rust structs.

Introduces the following macros:

  • offset_of! for obtaining the offset of a member of a struct.
  • span_of! for obtaining the range that a field, or fields, span.

memoffset works under no_std environments.

Usage

Add the following dependency to your Cargo.toml:

[dependencies]
memoffset = "0.5"

These versions will compile fine with rustc versions greater or equal to 1.20.

Add the following lines at the top of your main.rs or lib.rs files.

#[macro_use]
extern crate memoffset;

Examples

#[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);
}

No runtime deps

~12KB