byteme

Macro to provide from() & into() implementations for a struct with either enums and positive integer field.

We have made the following assumptions about the fields of the struct:

• The fields are public.
• The fields will have the following types
  • u8
  • u16
  • u32
  • u64
  • u128
  • usize
  • [u8]
  • 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 #[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.

Example

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],
  #[byte_me(u32)]
  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