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### `threshold-rs`: threshold data structures in Rust!

#### Example
Assume multiset `X` is `{10: 1, 8: 2, 6: 3, 5: 1}`.
This means that event `10` was seen once, event `8` twice, and so on.

Assume that these events come from vector clocks, and thus seeing event 10 means seeing all events from 1 to 10.

If, for example, we want the event that was seen at least 4 times (i.e. our [threshold](https://vitorenes.org/post/2018/11/threshold-union/) is 4), we should get event `6`.
    
Assume `threshold(u64, X) -> Option<u64>` where the first argument is the threshold desired and the output the event that passes the threshold (in case there's one). Then:
- `threshold(1, X) = Some(10)`
- `threshold(2, X) = Some(8)`
- `threshold(3, X) = Some(8)`
- `threshold(4, X) = Some(6)`
- `threshold(7, X) = Some(5)`
- `threshold(8, X) = None`

#### Code Example
```rust
use threshold::{clock, *};

let vclock_0 = clock::vclock_from_seqs(vec![10, 5, 5]);
let vclock_1 = clock::vclock_from_seqs(vec![8, 10, 6]);
let vclock_2 = clock::vclock_from_seqs(vec![9, 8, 7]);

let mut tclock = TClock::new();
tclock.add(vclock_0);
tclock.add(vclock_1);
tclock.add(vclock_2);

let vclock_t1 = clock::vclock_from_seqs(vec![10, 10, 7]);
let vclock_t2 = clock::vclock_from_seqs(vec![9, 8, 6]);
let vclock_t3 = clock::vclock_from_seqs(vec![8, 5, 5]);

assert_eq!(tclock.threshold_union(1), vclock_t1);
assert_eq!(tclock.threshold_union(2), vclock_t2);
assert_eq!(tclock.threshold_union(3), vclock_t3);
```

## License

Licensed under either of

 * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.