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:

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.

```rust,ignore

[macro_use]

extern crate memoffset; ```

Examples

```rust

[macro_use]

extern crate memoffset;

[repr(C, packed)]

struct Foo { a: u32, b: u32, c: [u8; 5], d: u32, }

fn main() { asserteq!(offsetof!(Foo, b), 4); asserteq!(offsetof!(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);

} ```