How to convert a slice into an array reference?

Question

I have an &[u8] and would like to turn it into an &[u8; 3] without copying. It should reference the original array. How can I do this?

Answer 1

As of Rust 1.34, you can use TryFrom / TryInto:

use std::convert::TryFrom;

fn example(slice: &[u8]) {
    let array = <&[u8; 3]>::try_from(slice);
    println!("{:?}", array);
}

fn example_mut(slice: &mut [u8]) {
    let array = <&mut [u8; 3]>::try_from(slice);
    println!("{:?}", array);
}