Function indices 

pub fn indices<'a, T>(
    slots: &'a Slots<T>,
    occupied: bool,
) -> impl Iterator<Item = usize> + 'a

Returns an iterator over the indices of occupied or unoccupied slots in the slots.

Example

use slots_slice;

let slots = [None, None, Some('a'), None, Some('b')];
let occupied_indices: Vec<usize> = slots_slice::indices(&slots, true).collect();
assert_eq!(occupied_indices, vec![2, 4]);

let unoccupied_indices: Vec<usize> = slots_slice::indices(&slots, false).collect();
assert_eq!(unoccupied_indices, vec![0, 1, 3]);