restructure files

1 files changed, 43 insertions, 0 deletions

diff --git a/src/iter/easter.rs b/src/iter/easter.rs
new file mode 100644
index 0000000..b41b270
--- /dev/null
+++ b/src/iter/easter.rs
@@ -0,0 +1,43 @@
+use chrono::prelude::*;
+
+pub fn easter(y: isize, offset: isize) -> Vec<isize> {
+    let a = y % 19;
+    let b = (y as f32 / 100_f32).floor() as isize;
+    let c = y % 100;
+    let d = (b as f32 / 4_f32).floor() as isize;
+    let e = b % 4;
+    let f = ((b + 8) as f32 / 25_f32).floor() as isize;
+    let g = ((b - f + 1) as f32 / 3_f32).floor() as isize;
+    let h = (19 * a + b - d - g + 15) % 30;
+    let i = (c as f32 / 4_f32).floor() as isize;
+    let k = c % 4;
+    let l = (32 + 2 * e + 2 * i - h - k) % 7;
+    let m = ((a + 11 * h + 22 * l) as f32 / 451_f32).floor() as isize;
+    let month = ((h + l - 7 * m + 114) as f32 / 31_f32).floor() as u32;
+    let day = ((h + l - 7 * m + 114) % 31) + 1;
+    let date = Utc
+        .ymd(y as i32, month, (day + offset) as u32)
+        .and_hms(0, 0, 0);
+    let year_start = Utc.ymd(y as i32, 1, 1).and_hms(0, 0, 0);
+    return vec![
+        ((date.timestamp() - year_start.timestamp()) as f32 / (60 * 60 * 24) as f32).ceil()
+            as isize,
+    ];
+}
+
+#[cfg(test)]
+mod test_easter_masks {
+    use super::*;
+
+    #[test]
+    fn easter_mask() {
+        let mask = easter(1997, 0);
+        assert_eq!(mask[0], 88);
+        let mask = easter(1998, 0);
+        assert_eq!(mask[0], 101);
+        let mask = easter(1999, 0);
+        assert_eq!(mask[0], 93);
+        let mask = easter(2000, 0);
+        assert_eq!(mask[0], 113);
+    }
+}