#proc-macro #bytes

macro byteme

Converts a struct into Vec<u8> and back. The conversion is Big Endian by default.

6 releases

0.0.5 Jun 14, 2022
0.0.4 Dec 1, 2021
0.0.3-dev Nov 30, 2021
0.0.2-dev Nov 30, 2021
0.0.1-dev Nov 30, 2021

#395 in Procedural macros


250 lines


A proc-macro to convert a struct into Vec and back by implemeting From trait on the struct. The conversion is Big Endian by default.

We have made the following assumptions about the the struct:

  • The struct must have fields.
  • The fields are public.
  • The fields have the following types
    • u8
    • u16
    • u32
    • u64
    • u128
    • usize
    • [u8; N]
    • an enum
  • For enum, we must attach a #[byte_me($size)] attribute, where size is any of the positive integer types.
  • The enum declration must have #[derive(FromPrimitive)] from the num-derive crate.

The num-derive crate is required to generate the FromPrimitive trait for enums. Having said that, the same functionality can be achieved using num-enum crate. It provides furthur control over the enum data types, and might prove handy. here is the discussion on the topic.


use byteme::ByteMe;
pub use num_derive::FromPrimitive;

#[derive(Debug, FromPrimitive)]
pub enum Mode {
  Unavailable = 0,
  Unauthenticated = 1,
  Authenticated = 2,
  Encrypted = 4,

#[derive(ByteMe, Debug)]
pub struct FrameOne {
  pub unused: [u8; 12],
  pub mode: Mode,
  pub challenge: [u8; 16],
  pub salt: [u8; 16],
  pub count: u32,
  pub mbz: [u8; 12],

let frame = FrameOne {
  unused: [0; 12],
  mode: Mode::Authenticated,
  challenge: [0; 16],
  salt: [0; 16],
  count: 1024,
  mbz: [0; 12],

let size = FrameOne::SIZE; // Get the number of bytes in the frame
let bytes: Vec<u8> = frame.into(); // Converts the frame into vector of bytes
let frame: FrameOne = bytes.into(); // Converts the bytes back to frame

License: Apache-2.0


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