36 lines
936 B
Rust
36 lines
936 B
Rust
use chrono::{Datelike, NaiveDate, Weekday};
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pub fn is_leap_year(year: i32) -> bool {
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NaiveDate::from_ymd_opt(year, 2, 29).is_some()
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}
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pub fn is_iso_leap_year(year: i32) -> bool {
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NaiveDate::from_isoywd_opt(year, 53, Weekday::Sun).is_some()
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}
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pub fn year_length(year: i32) -> u32 {
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NaiveDate::from_ymd(year, 12, 31).ordinal()
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}
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pub fn month_length(year: i32, month: u32) -> u32 {
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NaiveDate::from_ymd_opt(year, month + 1, 1)
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.unwrap_or_else(|| NaiveDate::from_ymd(year + 1, 1, 1))
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.pred()
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.day()
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}
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// Length of an ISO week year in days.
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pub fn iso_year_length(year: i32) -> u32 {
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if is_iso_leap_year(year) {
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53 * 7
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} else {
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52 * 7
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}
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}
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pub fn add_months(year: i32, month: u32, delta: i32) -> (i32, u32) {
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let month0 = (month as i32) - 1 + delta;
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let year = year + month0.div_euclid(12);
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let month = month0.rem_euclid(12) as u32 + 1;
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(year, month)
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}
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