1 | //! Utility functions. |
2 | |
3 | /// Returns if the provided year is a leap year in the proleptic Gregorian calendar. Uses |
4 | /// [astronomical year numbering](https://en.wikipedia.org/wiki/Astronomical_year_numbering). |
5 | /// |
6 | /// ```rust |
7 | /// # use time::util::is_leap_year; |
8 | /// assert!(!is_leap_year(1900)); |
9 | /// assert!(is_leap_year(2000)); |
10 | /// assert!(is_leap_year(2004)); |
11 | /// assert!(!is_leap_year(2005)); |
12 | /// assert!(!is_leap_year(2100)); |
13 | /// ``` |
14 | pub const fn is_leap_year(year: i32) -> bool { |
15 | year % 4 == 0 && (year % 25 != 0 || year % 16 == 0) |
16 | } |
17 | |
18 | /// Get the number of calendar days in a given year. |
19 | /// |
20 | /// The returned value will always be either 365 or 366. |
21 | /// |
22 | /// ```rust |
23 | /// # use time::util::days_in_year; |
24 | /// assert_eq!(days_in_year(1900), 365); |
25 | /// assert_eq!(days_in_year(2000), 366); |
26 | /// assert_eq!(days_in_year(2004), 366); |
27 | /// assert_eq!(days_in_year(2005), 365); |
28 | /// assert_eq!(days_in_year(2100), 365); |
29 | /// ``` |
30 | pub const fn days_in_year(year: i32) -> u16 { |
31 | if is_leap_year(year) { 366 } else { 365 } |
32 | } |
33 | |
34 | /// Get the number of weeks in the ISO year. |
35 | /// |
36 | /// The returned value will always be either 52 or 53. |
37 | /// |
38 | /// ```rust |
39 | /// # use time::util::weeks_in_year; |
40 | /// assert_eq!(weeks_in_year(2019), 52); |
41 | /// assert_eq!(weeks_in_year(2020), 53); |
42 | /// ``` |
43 | pub const fn weeks_in_year(year: i32) -> u8 { |
44 | match year.rem_euclid(400) { |
45 | 4 | 9 | 15 | 20 | 26 | 32 | 37 | 43 | 48 | 54 | 60 | 65 | 71 | 76 | 82 | 88 | 93 | 99 |
46 | | 105 | 111 | 116 | 122 | 128 | 133 | 139 | 144 | 150 | 156 | 161 | 167 | 172 | 178 |
47 | | 184 | 189 | 195 | 201 | 207 | 212 | 218 | 224 | 229 | 235 | 240 | 246 | 252 | 257 |
48 | | 263 | 268 | 274 | 280 | 285 | 291 | 296 | 303 | 308 | 314 | 320 | 325 | 331 | 336 |
49 | | 342 | 348 | 353 | 359 | 364 | 370 | 376 | 381 | 387 | 392 | 398 => 53, |
50 | _ => 52, |
51 | } |
52 | } |
53 | |