ncalendar

 1/// Represents a time span between two dates.
 2pub struct TimeSpan {
 3    start: time::Date,
 4    end: time::Date,
 5}
 6
 7/// Iterates over a time span by included days.
 8pub struct DayIterator<'a> {
 9    cur: &'a TimeSpan,
10    off: i64, // offset in days
11}
12
13impl<'a> Iterator for DayIterator<'a> {
14    type Item = time::Date;
15
16    fn next(&mut self) -> Option<Self::Item> {
17        let cur = &self.cur;
18        match cur.start.checked_add(time::Duration::days(self.off)) {
19            Some(ndate) => {
20                if ndate > cur.end {
21                    return None;
22                }
23                self.off += 1;
24                return Some(ndate);
25            }
26            None => return None,
27        }
28    }
29}
30
31impl TimeSpan {
32    pub fn new(day: time::Date, back: time::Duration, forward: time::Duration) -> Option<Self> {
33        let start = day.checked_sub(back)?;
34        let end = day.checked_add(forward)?;
35
36        Some(TimeSpan { start, end })
37    }
38
39    /// Iterate over all days in the given time span.
40    pub fn iter(&self) -> DayIterator {
41        return DayIterator { cur: self, off: 0 };
42    }
43}
44
45////////////////////////////////////////////////////////////////////////
46
47#[cfg(test)]
48mod tests {
49    use super::*;
50    use time::macros::date;
51
52    #[test]
53    fn iterator() {
54        let d = date!(1980 - 03 - 20);
55        let t = TimeSpan::new(d, time::Duration::days(0), time::Duration::days(1)).unwrap();
56
57        let mut it: DayIterator = t.iter();
58        assert_eq!(it.next(), Some(date!(1980 - 03 - 20)));
59        assert_eq!(it.next(), Some(date!(1980 - 03 - 21)));
60        assert_eq!(it.next(), None);
61    }
62}