Add end-of-month type/calc

Adds util module

1 files changed, 36 insertions, 0 deletions

diff --git a/src/util.rs b/src/util.rs
new file mode 100644
index 0000000..3062c84
--- /dev/null
+++ b/src/util.rs
@@ -0,0 +1,36 @@
+
+#[inline]
+pub fn get_num_of_days_in_month(y: i32, m: u32) -> u32 {
+    if m == 1 || m == 3 || m == 5 || m == 7 || m == 8 || m == 10 || m == 12 {
+        31
+    } else if m == 2 {
+        if is_leap_year(y) {
+            29
+        } else {
+            28
+        }
+    } else {
+        30
+    }
+}
+
+#[inline]
+pub fn is_leap_year(y: i32) -> bool {
+    (y % 4 == 0) && (y % 100 != 0 || y % 400 == 0)
+}
+
+#[test]
+fn test_is_leap_year() {
+    let leaps = [ 1880, 1884, 1888, 1892, 1896, 1904, 1908, 1912, 1916, 1920, 1924, 1928, 1932,
+        1936, 1940, 1944, 1948, 1952, 1956, 1960, 1964, 1968, 1972, 1976, 1980, 1984, 1988, 1992,
+        1996, 2000, 2004, 2008, 2012, 2020, 2024, 2028, 2032, 2036, 2040, 2044, 2048, 2052, 2056,
+        2060, 2064, 2068, 2072, 2076, 2080, 2084, 2088, 2092, 2096, 2104, 2108, 2112, 2116, 2120,
+        2124, 2128, 2132, 2136, 2140, 2144, 2148, 2152, 2156, 2160, 2164, 2168, 2172, 2176, 2180,
+        2184, 2188, 2192, 2196, 2204, 2208 ];
+
+    for i in leaps.iter() {
+        assert!(is_leap_year(*i), "Is no leap year: {}", i);
+        assert!(!is_leap_year(*i + 1), "Seems to be leap year: {}, but should not be", i + 1);
+    }
+
+}