collection 0.1.1

Deterministic, copy-on-write balanced search trees
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

use std::hash::{Hash, Hasher};

use seahash::SeaHasher;

pub trait Weight {
    fn weight_hash(&self) -> u64;

    fn weight(&self) -> usize {
        // count leading zeroes
        // TODO: use extended instructions when supported
        let mut w = 0;
        let a = self.weight_hash();
        loop {
            if a >> (63 - w) == 1 {
                return w;
            }
            w += 1;
        }
    }
}

impl<T> Weight for T
    where T: Hash
{
    fn weight_hash(&self) -> u64 {
        let mut hasher = SeaHasher::new();
        self.hash(&mut hasher);
        hasher.finish()
    }
}