orx_split_vec/common_traits/iterator/
iter.rs

1use super::reductions;
2use crate::{Growth, SplitVec, fragment::fragment_struct::Fragment};
3use core::iter::FusedIterator;
4
5impl<'a, T, G: Growth> IntoIterator for &'a SplitVec<T, G> {
6    type Item = &'a T;
7    type IntoIter = Iter<'a, T>;
8
9    fn into_iter(self) -> Self::IntoIter {
10        Self::IntoIter::new(&self.fragments)
11    }
12}
13
14/// Iterator over the `SplitVec`.
15///
16/// This struct is created by `SplitVec::iter()` method.
17#[derive(Debug)]
18#[must_use = "iterators are lazy and do nothing unless consumed"]
19pub struct Iter<'a, T> {
20    outer: core::slice::Iter<'a, Fragment<T>>,
21    inner: core::slice::Iter<'a, T>,
22}
23
24impl<T> Default for Iter<'_, T> {
25    fn default() -> Self {
26        Self {
27            outer: Default::default(),
28            inner: Default::default(),
29        }
30    }
31}
32
33impl<'a, T> Iter<'a, T> {
34    pub(crate) fn new(fragments: &'a [Fragment<T>]) -> Self {
35        let mut outer = fragments.iter();
36        let inner = outer.next().map(|x| x.iter()).unwrap_or([].iter());
37        Self { outer, inner }
38    }
39
40    fn next_fragment(&mut self) -> Option<&'a T> {
41        match self.outer.next() {
42            Some(f) => {
43                self.inner = f.iter();
44                self.next()
45            }
46            None => None,
47        }
48    }
49
50    #[inline(always)]
51    fn remaining_len(&self) -> usize {
52        self.inner.len() + self.outer.clone().map(|x| x.len()).sum::<usize>()
53    }
54}
55
56impl<T> Clone for Iter<'_, T> {
57    fn clone(&self) -> Self {
58        Self {
59            outer: self.outer.clone(),
60            inner: self.inner.clone(),
61        }
62    }
63}
64
65impl<'a, T> Iterator for Iter<'a, T> {
66    type Item = &'a T;
67
68    #[inline(always)]
69    fn next(&mut self) -> Option<Self::Item> {
70        let next_element = self.inner.next();
71        match next_element.is_some() {
72            true => next_element,
73            false => self.next_fragment(),
74        }
75    }
76
77    // override default implementations
78
79    fn all<F>(&mut self, f: F) -> bool
80    where
81        Self: Sized,
82        F: FnMut(Self::Item) -> bool,
83    {
84        reductions::all(&mut self.outer, &mut self.inner, f)
85    }
86
87    fn any<F>(&mut self, f: F) -> bool
88    where
89        Self: Sized,
90        F: FnMut(Self::Item) -> bool,
91    {
92        reductions::any(&mut self.outer, &mut self.inner, f)
93    }
94
95    #[inline(always)]
96    fn count(self) -> usize
97    where
98        Self: Sized,
99    {
100        self.remaining_len()
101    }
102
103    fn fold<B, F>(mut self, init: B, f: F) -> B
104    where
105        Self: Sized,
106        F: FnMut(B, Self::Item) -> B,
107    {
108        reductions::fold(&mut self.outer, &mut self.inner, init, f)
109    }
110
111    fn last(self) -> Option<Self::Item>
112    where
113        Self: Sized,
114    {
115        match self.outer.last() {
116            Some(x) => x.last(),
117            _ => self.inner.last(),
118        }
119    }
120
121    fn max(self) -> Option<Self::Item>
122    where
123        Self: Sized,
124        Self::Item: Ord,
125    {
126        let a = self.inner.max();
127        let b = self.outer.filter_map(|x| x.iter().max()).max();
128        inner_outer_reduce(a, b, core::cmp::max)
129    }
130
131    fn min(self) -> Option<Self::Item>
132    where
133        Self: Sized,
134        Self::Item: Ord,
135    {
136        let a = self.inner.min();
137        let b = self.outer.filter_map(|x| x.iter().min()).min();
138        inner_outer_reduce(a, b, core::cmp::min)
139    }
140
141    fn nth(&mut self, n: usize) -> Option<Self::Item> {
142        if self.inner.len() == 0 {
143            let fragment = self.outer.next()?;
144            self.inner = fragment.iter()
145        }
146
147        let mut inner_len = self.inner.len();
148        let mut n = n;
149        while n >= inner_len {
150            n -= inner_len;
151            let fragment = self.outer.next()?;
152            self.inner = fragment.iter();
153            inner_len = fragment.len();
154        }
155
156        self.inner.nth(n)
157    }
158
159    fn reduce<F>(mut self, f: F) -> Option<Self::Item>
160    where
161        Self: Sized,
162        F: FnMut(Self::Item, Self::Item) -> Self::Item,
163    {
164        reductions::reduce(&mut self.outer, &mut self.inner, f)
165    }
166
167    fn size_hint(&self) -> (usize, Option<usize>) {
168        let len = self.remaining_len();
169        (len, Some(len))
170    }
171}
172
173impl<T> FusedIterator for Iter<'_, T> {}
174
175impl<T> ExactSizeIterator for Iter<'_, T> {
176    #[inline(always)]
177    fn len(&self) -> usize {
178        self.remaining_len()
179    }
180}
181
182// helper functions
183
184fn inner_outer_reduce<'a, T, F>(a: Option<&'a T>, b: Option<&'a T>, compare: F) -> Option<&'a T>
185where
186    F: Fn(&'a T, &'a T) -> &'a T,
187{
188    match (a, b) {
189        (Some(a), Some(b)) => Some(compare(a, b)),
190        (Some(a), None) => Some(a),
191        _ => b,
192    }
193}
orx_split_vec/common_traits/iterator/iter.rs

orx_split_vec/common_traits/iterator/
iter.rs
