Move all crates into a crates directory (#1940)

crates/egui_extras/src/datepicker/mod.rs

@@ -0,0 +1,34 @@
+mod button;
+mod popup;
+
+pub use button::DatePickerButton;
+use chrono::{Date, Datelike, Duration, NaiveDate, Utc, Weekday};
+
+#[derive(Debug)]
+struct Week {
+    number: u8,
+    days: Vec<Date<Utc>>,
+}
+
+fn month_data(year: i32, month: u32) -> Vec<Week> {
+    let first = Date::from_utc(NaiveDate::from_ymd(year, month, 1), Utc);
+    let mut start = first;
+    while start.weekday() != Weekday::Mon {
+        start = start.checked_sub_signed(Duration::days(1)).unwrap();
+    }
+    let mut weeks = vec![];
+    let mut week = vec![];
+    while start < first || start.month() == first.month() || start.weekday() != Weekday::Mon {
+        week.push(start);
+
+        if start.weekday() == Weekday::Sun {
+            weeks.push(Week {
+                number: start.iso_week().week() as u8,
+                days: week.drain(..).collect(),
+            });
+        }
+        start = start.checked_add_signed(Duration::days(1)).unwrap();
+    }
+
+    weeks
+}