1//! The module contains [`LimitColumns`] records iterator.
2
3use crate::grid::records::IntoRecords;
4
5/// An iterator which limits amount of columns.
6#[derive(Debug)]
7pub struct LimitColumns<I> {
8 records: I,
9 limit: usize,
10}
11
12impl LimitColumns<()> {
13 /// Creates new [`LimitColumns`].
14 pub fn new<I: IntoRecords>(records: I, limit: usize) -> LimitColumns<I> {
15 LimitColumns { records, limit }
16 }
17}
18
19impl<I> IntoRecords for LimitColumns<I>
20where
21 I: IntoRecords,
22{
23 type Cell = I::Cell;
24 type IterColumns = LimitColumnsColumnsIter<<I::IterColumns as IntoIterator>::IntoIter>;
25 type IterRows = LimitColumnsIter<<I::IterRows as IntoIterator>::IntoIter>;
26
27 fn iter_rows(self) -> Self::IterRows {
28 LimitColumnsIter {
29 iter: self.records.iter_rows().into_iter(),
30 limit: self.limit,
31 }
32 }
33}
34
35/// An iterator over rows for [`LimitColumns`].
36#[derive(Debug)]
37pub struct LimitColumnsIter<I> {
38 iter: I,
39 limit: usize,
40}
41
42impl<I> Iterator for LimitColumnsIter<I>
43where
44 I: Iterator,
45 I::Item: IntoIterator,
46 <I::Item as IntoIterator>::Item: AsRef<str>,
47{
48 type Item = LimitColumnsColumnsIter<<I::Item as IntoIterator>::IntoIter>;
49
50 fn next(&mut self) -> Option<Self::Item> {
51 let iter: ::Item = self.iter.next()?;
52 Some(LimitColumnsColumnsIter {
53 iter: iter.into_iter(),
54 limit: self.limit,
55 })
56 }
57}
58
59/// An iterator over columns for [`LimitColumns`].
60#[derive(Debug)]
61pub struct LimitColumnsColumnsIter<I> {
62 iter: I,
63 limit: usize,
64}
65
66impl<I> Iterator for LimitColumnsColumnsIter<I>
67where
68 I: Iterator,
69 I::Item: AsRef<str>,
70{
71 type Item = I::Item;
72
73 fn next(&mut self) -> Option<Self::Item> {
74 if self.limit == 0 {
75 return None;
76 }
77
78 self.limit -= 1;
79
80 self.iter.next()
81 }
82}
83