Convert Vec<u8> to Vec<{float}> in rust

Question

I'm looking to pass a message through a channel. The message type is bytes::Bytes due to the implementation of the channel.

The message I want to send is about a vector of floats (Vec<{float}>) and I convert it like this:

let flatten_array: Vec<u8> = correct_centroids
            .clone()
            .into_iter()
            .flat_map(|x| f32::to_le_bytes(x).to_vec().into_iter())
            .collect();

 let data = Bytes::from(flatten_array);

My question is, how can I reconvert the Vec<u8> that I get back to Vec<{float}> again.

Is there any other better way to serialize the message?

Answer 1

You can use chunks to split the Vec (or more specifically any slice) up, convert to arrays and call from_le_bytes, i.e. almost just do the reverse of what you did:

fn u8_to_f32_vec(v: &[u8]) -> Vec<f32> {
    v.chunks_exact(4)
        .map(TryInto::try_into)
        .map(Result::unwrap)
        .map(f32::from_le_bytes)
        .collect()
}

The only problem is that chunks does only give slices, not array references. In future (or on nightly) that can be written with the array_chunks method instead:

#![feature(array_chunks)]
fn u8_to_f32_vec(v: &[u8]) -> Vec<f32> {
    v.array_chunks::<4>()
        .copied()
        .map(f32::from_le_bytes)
        .collect()
}

Playground

Note: Both versions will silently drop excess bytes at the end of the slice.