Trait bytepack::Packed [−] [src]

pub trait Packed {
    fn switch_endianness(&mut self);
}

This trait both identifies a type which holds his data packed together in memory and a type which offers a switch_endianness method. This trait is voluntarily not implemented for isize and usize because their size can vary from one system to another.

Example

If you would like to read and write one of your struct using bytepack, you can derive Packed for it:

extern crate bytepack;
#[macro_use]
extern crate bytepack_derive;
 
use std::fs::File;
use bytepack::{LEUnpacker, Packed};

#[derive(Packed)]
struct Vector {
   x: f32,
   y: f32,
   z: f32,
}

#[derive(Packed)]
struct RGB(u8,u8,u8);

fn main() {
    let mut file = File::open("test").unwrap();
    let vector : Vector = file.unpack().unwrap();
    let rgb : RGB = file.unpack().unwrap();
}

Please note that also specifying #[repr(packed)] might make sense if you want to get rid of the padding inside your structure.

Packed can only be derived for strutures only composed of types implementing Packed themselves. If you which to circumvent this restriction you can implement Packed yourselve, however you need to make sure your struct is indeed "packed" and that reading and writing it as one continuous memory zone makes sense. For example the following structures are not "packed" because they all hold a reference to their data.

struct NotPacked1 {
    name: String
}

struct NotPacked2 {
    numbers: Vec<f32>
}

struct NotPacked3 {
    count: Rc<u64>
}

Required Methods

Perform an in-place switch of the endianness. This might be a no-op in some cases.

Implementors