more-itertools 0.1.6

A rust implementation of python more-itertools
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
145
146
147
148
149
150
151

use std::collections::VecDeque;
use crate::error;
use crate::error::Error;

pub struct ZipEqual<T> {
    buf: VecDeque<T>,
    buf2: VecDeque<Option<T>>,
    iter_vec: Vec<Box<dyn Iterator<Item = Result<T,Error>>>>,
    iter_finished: bool
}

impl<T> Iterator for ZipEqual<T> 
where
T: Clone + 'static
{
    type Item = Result<Vec<T>, Error>;

    fn next(&mut self) -> Option<Self::Item> {
        loop {
            if self.iter_finished {
                return None;
            }

            // if self.buf.len() > 0 {
            //     let ret = self.buf.pop_front().unwrap();
            //     return Some(ret);
            // }

            assert_eq!(0, self.buf2.len());

            for i in self.iter_vec.iter_mut() {
                if let Some(v) = i.next() {
                    match v {
                        Ok(ok_v) => {
                            self.buf2.push_back(Some(ok_v));
                        },
                        Err(err_v) => {
                            self.iter_finished = true;
                            return Some(Err(err_v));
                        }
                    }
                } else {
                    self.buf2.push_back(None);
                }
            }

            if self.buf2.iter().all(|x| match x {
                None => { return true; },
                Some(_) => { return false; }
            }) {
                self.iter_finished = true;
            } else {
                while self.buf2.len() > 0 {
                    match self.buf2.front() {
                        None => {
                            self.buf2.pop_front();
                            continue;
                        },
                        Some(v) => {
                            match v {
                                None => {
                                    self.buf2.pop_front();
                                    continue;
                                },
                                Some(v2) => {
                                    self.buf.push_back(v2.clone());
                                    self.buf2.pop_front();
                                }
                            }
                        }
                    }
                }
                if self.buf.len() != self.iter_vec.len() {
                    self.iter_finished = true;
                    return Some(Err(error::any_error(error::Kind::IteratorError, "Iterables have different lengths".to_string())));
                } else {
                    let mut ret = Vec::new();
                    while self.buf.len() > 0 {
                        ret.push(self.buf.pop_front().unwrap());
                    }
                    return Some(Ok(ret));
                }
            }
        }   
    }
}

pub fn zip_equal<T>(iter_vec: Vec<Box<dyn Iterator<Item = Result<T,Error>>>>) -> Box<dyn Iterator<Item = Result<Vec<T>,Error>>> 
where T: Clone + 'static
{
    Box::new(ZipEqual {
        buf: VecDeque::new(),
        buf2: VecDeque::new(),
        iter_vec,
        iter_finished: false
    })
}

#[cfg(test)]
mod tests {

    use crate::utils::{generate_okok_iterator, generate_okokerr_iterator};

    use super::*;

    #[test]
    fn test1() {
        let mut v = Vec::new();
        v.push(generate_okok_iterator(vec![1,2,3]));
        v.push(generate_okok_iterator(vec![4,5,6]));
        v.push(generate_okok_iterator(vec![6,7,8]));

        let mut iter = zip_equal(v);

        assert_eq!(Some(Ok(vec![1, 4, 6])), iter.next());
        assert_eq!(Some(Ok(vec![2, 5, 7])), iter.next());
        assert_eq!(Some(Ok(vec![3, 6, 8])), iter.next());
        assert_eq!(None, iter.next());
    }

    #[test]
    fn test2() {
        let mut v = Vec::new();
        v.push(generate_okok_iterator(vec![1,2,3]));
        v.push(generate_okok_iterator(vec![4,5]));
        v.push(generate_okok_iterator(vec![6,7,8]));

        let mut iter = zip_equal(v);

        assert_eq!(Some(Ok(vec![1, 4, 6])), iter.next());
        assert_eq!(Some(Ok(vec![2, 5, 7])), iter.next());
        assert_eq!(error::Kind::IteratorError, iter.next().unwrap().err().unwrap().kind());
        assert_eq!(None, iter.next());
    }

    #[test]
    fn test3() {
        let mut v = Vec::new();
        v.push(generate_okok_iterator(vec![1,2,3]));
        v.push(generate_okokerr_iterator(vec![4,5], error::overflow_error("[test]".to_string())));
        v.push(generate_okok_iterator(vec![6,7,8]));

        let mut iter = zip_equal(v);

        assert_eq!(Some(Ok(vec![1, 4, 6])), iter.next());
        assert_eq!(Some(Ok(vec![2, 5, 7])), iter.next());
        assert_eq!(error::Kind::OverflowError, iter.next().unwrap().err().unwrap().kind());
        assert_eq!(None, iter.next());
    }

}