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
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92

use crate::private::Entry;

/// Read-only iterator to access all occupied slots.
pub struct Iter<'a, IT> {
    inner: core::slice::Iter<'a, Entry<IT>>,
}

impl<'a, IT> Iter<'a, IT> {
    pub(crate) fn from_entry_slice(inner: &'a [Entry<IT>]) -> Self {
        Self {
            inner: inner.iter(),
        }
    }
}

impl<'a, IT> Iterator for Iter<'a, IT> {
    type Item = &'a IT;

    fn next(&mut self) -> Option<Self::Item> {
        for slot in self.inner.by_ref() {
            if let Entry::Used(ref item) = slot {
                return Some(item);
            }
        }
        None
    }
}

/// Read-write iterator to access all occupied slots.
pub struct IterMut<'a, IT> {
    inner: core::slice::IterMut<'a, Entry<IT>>,
}

impl<'a, IT> IterMut<'a, IT> {
    pub(crate) fn from_entry_slice(inner: &'a mut [Entry<IT>]) -> Self {
        Self {
            inner: inner.iter_mut(),
        }
    }
}

impl<'a, IT> Iterator for IterMut<'a, IT> {
    type Item = &'a mut IT;

    fn next(&mut self) -> Option<Self::Item> {
        for slot in self.inner.by_ref() {
            if let Entry::Used(ref mut item) = slot {
                return Some(item);
            }
        }
        None
    }
}

#[cfg(test)]
mod iter_test {
    use crate::{slots::Slots, unrestricted::UnrestrictedSlots};

    #[test]
    fn sanity_check() {
        let mut slots: Slots<_, 3> = Slots::new();

        let _k1 = slots.store(1).unwrap();
        let k2 = slots.store(2).unwrap();
        let _k3 = slots.store(3).unwrap();

        slots.take(k2);

        let mut iter = slots.iter();
        // iterator does not return elements in order of store
        assert_eq!(Some(&3), iter.next());
        assert_eq!(Some(&1), iter.next());
        assert_eq!(None, iter.next());

        for &_ in slots.iter() {}
    }

    #[test]
    fn test_mut() {
        let mut slots: UnrestrictedSlots<_, 3> = UnrestrictedSlots::new();

        let _k1 = slots.store(1).unwrap();
        let k2 = slots.store(2).unwrap();
        let _k3 = slots.store(3).unwrap();

        for k in slots.iter_mut() {
            *k *= 2;
        }

        assert_eq!(Some(4), slots.take(k2));
    }
}