irox-tools 0.11.1

Stuff that should have been in the Rust STL, but aren't
Documentation 
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
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

// SPDX-License-Identifier: MIT
// Copyright 2024 IROX Contributors
//

extern crate alloc;

use alloc::collections::VecDeque;
use alloc::vec::Vec;

pub struct Joining<I, E>
where
    I: Iterator<Item = E>,
    E: Clone,
{
    wrapped: I,
    delimiter: E,
    peeked: Option<E>,
    delim: Option<E>,
}

impl<I, E> Joining<I, E>
where
    I: Iterator<Item = E>,
    E: Clone,
{
    pub fn new(mut wrapped: I, delim: E) -> Self {
        let peeked = wrapped.next();
        Self {
            wrapped,
            delimiter: delim,
            peeked,
            delim: None,
        }
    }
}

impl<I, E> Iterator for Joining<I, E>
where
    I: Iterator<Item = E>,
    E: Clone,
{
    type Item = E;

    fn next(&mut self) -> Option<Self::Item> {
        if let Some(delim) = self.delim.take() {
            return Some(delim);
        }
        if let Some(peek) = self.peeked.take() {
            self.peeked = self.wrapped.next();
            if self.peeked.is_some() {
                self.delim = Some(self.delimiter.clone());
            }
            return Some(peek);
        }
        None
    }
}

pub struct MultiJoining<I, E>
where
    I: Iterator<Item = E>,
    E: Clone,
{
    wrapped: I,
    delimiters: Vec<E>,
    peeked: Option<E>,
    delim: VecDeque<E>,
}

impl<I, E> MultiJoining<I, E>
where
    I: Iterator<Item = E>,
    E: Clone,
{
    pub fn new(mut wrapped: I, delim: &[E]) -> Self {
        let peeked = wrapped.next();
        Self {
            wrapped,
            delimiters: Vec::from(delim),
            peeked,
            delim: VecDeque::with_capacity(delim.len()),
        }
    }
}

impl<I, E> Iterator for MultiJoining<I, E>
where
    I: Iterator<Item = E>,
    E: Clone,
{
    type Item = E;

    fn next(&mut self) -> Option<Self::Item> {
        if let Some(delim) = self.delim.pop_front() {
            return Some(delim);
        }
        if let Some(peek) = self.peeked.take() {
            self.peeked = self.wrapped.next();
            if self.peeked.is_some() {
                for elem in &self.delimiters {
                    self.delim.push_back(elem.clone());
                }
            }
            return Some(peek);
        }
        None
    }
}

#[cfg(test)]
mod test {
    use crate::iterators::Itertools;

    #[test]
    pub fn test_joining() {
        let mut iter = ["A", "B", "C", "D"].iter().joining(&"z");

        assert_eq!(iter.next().unwrap(), &"A");
        assert_eq!(iter.next().unwrap(), &"z");
        assert_eq!(iter.next().unwrap(), &"B");
        assert_eq!(iter.next().unwrap(), &"z");
        assert_eq!(iter.next().unwrap(), &"C");
        assert_eq!(iter.next().unwrap(), &"z");
        assert_eq!(iter.next().unwrap(), &"D");
        assert_eq!(iter.next(), None);
    }

    #[test]
    pub fn test_multi_joining() {
        let mut iter = ["A", "B", "C", "D"].iter().joining_multi(&[&"y", &"z"]);

        assert_eq!(iter.next().unwrap(), &"A");
        assert_eq!(iter.next().unwrap(), &"y");
        assert_eq!(iter.next().unwrap(), &"z");
        assert_eq!(iter.next().unwrap(), &"B");
        assert_eq!(iter.next().unwrap(), &"y");
        assert_eq!(iter.next().unwrap(), &"z");
        assert_eq!(iter.next().unwrap(), &"C");
        assert_eq!(iter.next().unwrap(), &"y");
        assert_eq!(iter.next().unwrap(), &"z");
        assert_eq!(iter.next().unwrap(), &"D");
        assert_eq!(iter.next(), None);
    }
}