refactor timestamp code a bit

1 files changed, 78 insertions, 0 deletions

diff --git a/src/time.rs b/src/time.rs
new file mode 100644
index 0000000..6261573
--- /dev/null
+++ b/src/time.rs
@@ -0,0 +1,78 @@
+use byteorder::{ByteOrder, BigEndian};
+use std::ops::Deref;
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
+use std::u64;
+
+const TAI64N_BASE: i64 = 4611686018427387914;
+
+#[derive(PartialEq, PartialOrd)]
+pub struct Tai64n {
+    tai64n: [u8; 12]
+}
+
+impl Tai64n {
+    pub fn now() -> Tai64n {
+        let mut tai64n = [0u8; 12];
+        let now = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
+        BigEndian::write_i64(&mut tai64n[0..], TAI64N_BASE + now.as_secs() as i64);
+        BigEndian::write_i32(&mut tai64n[8..], now.subsec_nanos() as i32);
+
+        Tai64n { tai64n }
+    }
+}
+
+impl Deref for Tai64n {
+    type Target = [u8; 12];
+
+    fn deref(&self) -> &[u8; 12] {
+        &self.tai64n
+    }
+}
+
+impl From<[u8; 12]> for Tai64n {
+    fn from(tai64n: [u8; 12]) -> Self {
+        Tai64n { tai64n }
+    }
+}
+
+lazy_static! {
+    pub static ref FOREVER:     Duration = Duration::from_secs(u64::MAX);
+    pub static ref FOREVER_AGO: Instant  = Instant::now() - *FOREVER;
+}
+
+pub struct Timestamp(Option<Instant>);
+
+impl Default for Timestamp {
+    fn default() -> Self {
+        Timestamp(None)
+    }
+}
+
+impl Deref for Timestamp {
+    type Target = Instant;
+
+    fn deref(&self) -> &Self::Target {
+        match self.0 {
+            Some(ref time) => time,
+            None           => &*FOREVER_AGO,
+        }
+    }
+}
+
+impl Timestamp {
+    pub fn now() -> Self {
+        Timestamp(Some(Instant::now()))
+    }
+
+    pub fn unset() -> Self {
+        Timestamp(None)
+    }
+
+    pub fn is_set(&self) -> bool {
+        self.0.is_some()
+    }
+
+    pub fn elapsed(&self) -> Duration {
+        Instant::now().duration_since(**self)
+    }
+}