1 files changed, 45 insertions, 0 deletions

diff --git a/src/zip/datetime.rs b/src/zip/datetime.rs
new file mode 100644
index 0000000..a4b1b55
--- /dev/null
+++ b/src/zip/datetime.rs
@@ -0,0 +1,45 @@
+use crate::zip::{ZipError, ZipResult};
+use chrono::{DateTime, Datelike, NaiveDate, TimeZone, Timelike};
+
+pub trait DosDateTime<Tz>: Sized {
+    fn from_dos_date_time(date: u16, time: u16, tz: Tz) -> ZipResult<Self>;
+
+    #[allow(dead_code)]
+    fn to_dos_date(&self) -> u16;
+
+    fn to_dos_time(&self) -> u16;
+}
+
+impl<Tz: TimeZone> DosDateTime<Tz> for DateTime<Tz> {
+    #[inline]
+    fn from_dos_date_time(date: u16, time: u16, tz: Tz) -> ZipResult<Self> {
+        Ok(NaiveDate::from_ymd_opt(
+            (date as i32 >> 9 & 0x7F) + 1980,
+            date as u32 >> 5 & 0xF,
+            date as u32 & 0x1F,
+        )
+        .ok_or(ZipError::InvalidDate)?
+        .and_hms_opt(
+            (time as u32 >> 11) & 0x1F,
+            (time as u32 >> 5) & 0x3F,
+            (time as u32 & 0x1F) * 2,
+        )
+        .ok_or(ZipError::InvalidTime)?
+        .and_local_timezone(tz)
+        .unwrap())
+    }
+
+    #[inline]
+    fn to_dos_date(&self) -> u16 {
+        (self.year() as u16 - 1980 & 0x7F) << 9
+            | (self.month() as u16 & 0xF) << 5
+            | self.day() as u16 & 0x1F
+    }
+
+    #[inline]
+    fn to_dos_time(&self) -> u16 {
+        (self.hour() as u16 & 0x1F) << 11
+            | (self.minute() as u16 & 0x3F) << 5
+            | self.second() as u16 / 2 & 0x1F
+    }
+}