Function from_bytes

crates/aiur/src/vk_codec.rs:355–375

Deserialize a `System ` from [`to_bytes`] output, requiring that every byte is consumed.

(bytes: &[u8])

  let mut lookups = Vec::with_capacity(lookup_count);
  for _ in 0..lookup_count {
    let multiplicity = seg.node_id()?;
    let arg_count = seg.u16()? as usize;
    let mut args = Vec::with_capacity(arg_count.min(1 << 16));
    for _ in 0..arg_count {
      args.push(seg.node_id()?);
    }
    lookups.push(Lookup { multiplicity, args });
  }

  let degrees = recompute_degrees(&nodes);
  // The graph's own max degree covers only the user roots (the serialized
  // `max_constraint_degree` is the combined user + analytic-logUp value).
  let user_max_degree = zeros
    .iter()
    .map(|z| degrees[usize::try_from(z.0).expect("node id")])
    .max()
    .unwrap_or(0);
  // The lookup prefix is exactly the nodes interned while compiling the
  // lookup expressions, all of which are reachable from (and bounded by)
  // the lookup roots — children always precede parents.
  let lookup_prefix_len = lookups
    .iter()
    .flat_map(|l| std::iter::once(l.multiplicity).chain(l.args.iter().copied()))
    .map(|id| id.0 as usize + 1)