time/iter/
month_iter.rs

1//! An infinite iterator over [`Month`]s.
2
3use core::iter::FusedIterator;
4
5use super::Rev;
6use crate::Month::{self, *};
7
8pub(super) const ALL_MONTHS: [Month; 12] = [
9    January, February, March, April, May, June, July, August, September, October, November,
10    December,
11];
12
13/// An infinite iterator over [`Month`]s.
14///
15/// This struct is created by [`Month::iter_from`] or [`MonthIter::new`].
16#[derive(Debug, Clone, PartialEq, Eq)]
17pub struct MonthIter {
18    current: Month,
19}
20
21impl MonthIter {
22    /// Create a new `MonthIter` starting at `start`.
23    ///
24    /// ```rust
25    /// # use time::{Month, iter::MonthIter};
26    /// let mut iter = MonthIter::new(Month::January);
27    /// assert_eq!(iter.next(), Some(Month::January));
28    /// assert_eq!(iter.next(), Some(Month::February));
29    /// assert_eq!(iter.next(), Some(Month::March));
30    /// ```
31    #[inline]
32    pub const fn new(start: Month) -> Self {
33        Self { current: start }
34    }
35
36    /// Make the iterator go in reverse order.
37    ///
38    /// ```rust
39    /// # use time::{Month, iter::MonthIter};
40    /// let mut iter = MonthIter::new(Month::January).rev();
41    /// assert_eq!(iter.next(), Some(Month::January));
42    /// assert_eq!(iter.next(), Some(Month::December));
43    /// assert_eq!(iter.next(), Some(Month::November));
44    /// ```
45    #[inline]
46    pub const fn rev(self) -> Rev<Self> {
47        Rev { iter: self }
48    }
49}
50
51impl Iterator for MonthIter {
52    type Item = Month;
53
54    #[inline]
55    fn next(&mut self) -> Option<Self::Item> {
56        let current = self.current;
57        self.current = current.next();
58        Some(current)
59    }
60
61    #[inline]
62    fn size_hint(&self) -> (usize, Option<usize>) {
63        (usize::MAX, None)
64    }
65
66    #[inline]
67    fn nth(&mut self, n: usize) -> Option<Self::Item> {
68        let result = self.current.nth_next((n % 12) as u8);
69        self.current = result.next();
70        Some(result)
71    }
72
73    fn count(self) -> usize {
74        panic!("`MonthIter` is infinite and cannot be counted")
75    }
76
77    fn last(self) -> Option<Self::Item> {
78        panic!("`MonthIter` is infinite and has no last element")
79    }
80
81    #[inline]
82    fn all<F>(&mut self, f: F) -> bool
83    where
84        F: FnMut(Self::Item) -> bool,
85    {
86        ALL_MONTHS.into_iter().all(f)
87    }
88
89    #[inline]
90    fn any<F>(&mut self, f: F) -> bool
91    where
92        F: FnMut(Self::Item) -> bool,
93    {
94        ALL_MONTHS.into_iter().any(f)
95    }
96
97    #[inline]
98    fn max(self) -> Option<Self::Item> {
99        Some(December)
100    }
101
102    #[inline]
103    fn min(self) -> Option<Self::Item> {
104        Some(January)
105    }
106
107    #[inline]
108    fn is_sorted(self) -> bool {
109        // The iterator will always have December followed by January, so it is not sorted.
110        false
111    }
112}
113
114impl Iterator for Rev<MonthIter> {
115    type Item = Month;
116
117    #[inline]
118    fn next(&mut self) -> Option<Self::Item> {
119        let current = self.iter.current;
120        self.iter.current = current.previous();
121        Some(current)
122    }
123
124    #[inline]
125    fn size_hint(&self) -> (usize, Option<usize>) {
126        (usize::MAX, None)
127    }
128
129    #[inline]
130    fn nth(&mut self, n: usize) -> Option<Self::Item> {
131        let result = self.iter.current.nth_prev((n % 12) as u8);
132        self.iter.current = result.previous();
133        Some(result)
134    }
135
136    fn count(self) -> usize {
137        panic!("`Rev<MonthIter>` is infinite and cannot be counted")
138    }
139
140    fn last(self) -> Option<Self::Item> {
141        panic!("`Rev<MonthIter>` is infinite and has no last element")
142    }
143
144    #[inline]
145    fn all<F>(&mut self, f: F) -> bool
146    where
147        F: FnMut(Self::Item) -> bool,
148    {
149        ALL_MONTHS.into_iter().all(f)
150    }
151
152    #[inline]
153    fn any<F>(&mut self, f: F) -> bool
154    where
155        F: FnMut(Self::Item) -> bool,
156    {
157        ALL_MONTHS.into_iter().any(f)
158    }
159
160    #[inline]
161    fn max(self) -> Option<Self::Item> {
162        Some(December)
163    }
164
165    #[inline]
166    fn min(self) -> Option<Self::Item> {
167        Some(January)
168    }
169
170    #[inline]
171    fn is_sorted(self) -> bool {
172        false
173    }
174}
175
176impl FusedIterator for MonthIter {}
177impl FusedIterator for Rev<MonthIter> {}
time/iter/month_iter.rs

time/iter/
month_iter.rs
