standard_lib/collections/cons/tree/
iter.rs

1use std::{mem, rc::Rc};
2
3use super::{ConsBranch, ConsNode};
4
5/// See [`ConsTree::iter`].
6pub struct Iter<'a, T> {
7    pub(crate) inner: Option<&'a ConsNode<T>>,
8}
9
10impl<'a, T> Iterator for Iter<'a, T> {
11    type Item = &'a T;
12
13    fn next(&mut self) -> Option<Self::Item> {
14        let ConsNode { value, next } = self.inner?;
15        self.inner = next.inner.as_deref();
16        Some(value)
17    }
18}
19
20impl<'a, T> Clone for Iter<'a, T> {
21    fn clone(&self) -> Self {
22        Self {
23            inner: self.inner.clone(),
24        }
25    }
26}
27
28/// See [`ConsTree::into_iter_owned`].
29pub struct OwnedIter<T: Clone> {
30    pub(crate) inner: ConsBranch<T>,
31}
32
33impl<T: Clone> OwnedIter<T> {
34    /// Returns all remaining elements of this iterator, as a `ConsTree`.
35    pub fn remainder(self) -> ConsBranch<T> {
36        self.inner
37    }
38}
39
40impl<T: Clone> Iterator for OwnedIter<T> {
41    type Item = T;
42
43    fn next(&mut self) -> Option<Self::Item> {
44        self.inner.pop_to_owned()
45    }
46}
47
48/// See [`ConsTree::into_iter_unique`].
49pub struct UniqueIter<T> {
50    pub(crate) inner: ConsBranch<T>,
51}
52
53impl<T> UniqueIter<T> {
54    /// Returns all remaining elements of this iterator, as a [`ConsTree`]. When used on an
55    /// exhausted `UniqueIter`, the list returned will contain all the shared items (of which there
56    /// may be none).
57    pub fn remainder(self) -> ConsBranch<T> {
58        self.inner
59    }
60}
61
62impl<T> Iterator for UniqueIter<T> {
63    type Item = T;
64
65    fn next(&mut self) -> Option<Self::Item> {
66        self.inner.pop_if_unique()
67    }
68}
69
70/// See [`ConsTree::into_iter_rc`].
71pub struct RcIter<T> {
72    pub(crate) inner: ConsBranch<T>,
73}
74
75impl<T> RcIter<T> {
76    /// Returns all remaining elements of this iterator, as a `ConsTree`.
77    pub fn remainder(self) -> ConsBranch<T> {
78        self.inner
79    }
80}
81
82impl<T> Iterator for RcIter<T> {
83    type Item = Rc<ConsNode<T>>;
84
85    fn next(&mut self) -> Option<Self::Item> {
86        let inner = mem::take(&mut self.inner.inner);
87
88        match inner {
89            Some(rc) => {
90                self.inner = rc.next.clone();
91                Some(rc)
92            },
93            None => {
94                self.inner.inner = inner;
95                None
96            },
97        }
98    }
99}
standard_lib/collections/cons/tree/iter.rs

standard_lib/collections/cons/tree/
iter.rs
