Flat directory/module structure

src/timer/wallclocktimer.rs

@@ -0,0 +1,30 @@
+use std::process::Child;
+use std::time::Instant;
+
+use crate::timer::{TimerStart, TimerStop};
+use crate::units::Second;
+
+pub struct WallClockTimer {
+    start: Instant,
+}
+
+impl TimerStart for WallClockTimer {
+    fn start() -> WallClockTimer {
+        WallClockTimer {
+            start: Instant::now(),
+        }
+    }
+
+    fn start_for_process(_: &Child) -> Self {
+        Self::start()
+    }
+}
+
+impl TimerStop for WallClockTimer {
+    type Result = Second;
+
+    fn stop(&self) -> Second {
+        let duration = self.start.elapsed();
+        duration.as_secs() as f64 + f64::from(duration.subsec_nanos()) * 1e-9
+    }
+}