use std::cmp::Ordering::*;

//
// This implementation fails the following test
//
#[test]
fn binary_search_returns_none() {
    let data = vec![1, 2, 3];
    let target = 10;
    assert_eq!(binary_search(&data, &target), None);
}

// Broken, didn't manage to debug sorry.
fn binary_search<T: Ord>(arr: &[T], elem: &T) -> Option<usize>
{
    let mut size = arr.len();
    let mut base = 0;

    while size > 0 {
        size /= 2;
        let mid = base + size;
        base = match arr[mid].cmp(elem) {
            Less    => mid,
            Greater => base,
            Equal   => return Some(mid)
        };
    }

    None
}