Function bao::decode::hash_from_outboard_encoded_nostd

pub fn hash_from_outboard_encoded_nostd<F1, F2, E>(
    content_read_exact_fn: F1, 
    outboard_read_exact_fn: F2
) -> Result<Hash, E> where
    F1: FnOnce(&mut [u8]) -> Result<(), E>,
    F2: FnMut(&mut [u8]) -> Result<(), E>, 

Given an outboard encoding, quickly determine the root hash by reading just the root node.

Depending on the content length, the outboard_read_exact_fn callback will be called one or two times, and the content_read_exact_fn will be called either one time or not at all.

Example

let input = b"foobar";
let (hash1, outboard) = bao::encode::encode_outboard_to_vec(input);
let mut content_reader = &input[..];
let mut outboard_reader = &*outboard;
let hash2 = bao::decode::hash_from_outboard_encoded_nostd(
    |buf| {
        let take = buf.len();
        buf.copy_from_slice(&content_reader[..take]);
        content_reader = &content_reader[take..];
        Ok::<(), ()>(())
    },
    |buf| {
        let take = buf.len();
        buf.copy_from_slice(&outboard_reader[..take]);
        outboard_reader = &outboard_reader[take..];
        Ok::<(), ()>(())
    },
).unwrap();
assert_eq!(hash1, hash2);