Unaligned reads & incorrect encoded sizes

[mumbleskates]

It looks like a number of methods, including at the very least UnsafeReader::unwire_u64, perform unsound unaligned reads which will cause the program to crash with assertions enabled. Additionally, structs which derive Wiring and Unwiring but have unused padding inside or outside the struct use mem::size_of::<T>() to calculate the encoded size of multiple values in <Vec<T> as Unwiring>::bytes_length, even though the actual byte size may be much shorter.

Here are a couple tests demonstrating the issues I found:

use wiring::prelude::*;

#[derive(Debug, PartialEq, Unwiring, Wiring)]
struct Syncopated {
    small: u8,
    big: u64,
}
#[derive(Debug, PartialEq, Unwiring, Wiring)]
struct Several {
    vec: Vec<Syncopated>,
}

#[test]
fn unaligned_read() {
    let a = Syncopated { small: 1, big: 2 };
    let mut buf = Vec::new();
    BufWire::new(&mut buf).wire(&a).unwrap();
    let b = BufUnWire::new(buf.as_slice()).unwire::<Syncopated>().unwrap();

    assert_eq!(a, b);
}

#[test]
fn incorrect_size_estimation() {
    let a = Several {
        vec: vec![Syncopated { small: 1, big: 2 }, Syncopated { small: 3, big: 4 }],
    };
    let mut buf = Vec::new();
    BufWire::new(&mut buf).wire(&a).unwrap();
    let b = BufUnWire::new(buf.as_slice()).unwire::<Several>().unwrap();

    assert_eq!(a, b);
}

[louaykamel]

Oh I see, thank you for highlighting the issues. I will dive into this during the weekend.