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