better human readable time from ns

tools/stopwatch.py

@@ -1,26 +1,8 @@
 from time import perf_counter_ns
+from .tools import human_readable_time_from_ns
 from .types import IntOrNone
 
 
-def get_time_string_from_ns(ns: int) -> str:
-    # mis, ns = ns // 1000, ns % 1000
-    # ms, mis = mis // 1000, mis % 1000
-    # s, ms = ms // 1000, ms % 1000
-    # m, s = s // 60, s % 60
-    # h, m = m // 60, m % 60
-    # d, h = h // 24, h % 24
-
-    units = ['ns', 'µs', 'ms', 's']
-    unit = 0
-    while ns > 1_000:
-        if unit > 3:
-            break
-        ns /= 1000
-        unit += 1
-
-    return "%1.2f%s" % (ns, units[unit])
-
-
 class StopWatch:
     started: IntOrNone = None
     stopped: IntOrNone = None
@@ -39,20 +21,20 @@ class StopWatch:
 
     reset = start
 
-    def elapsed(self) -> float:
+    def elapsed(self) -> int:
         if self.stopped is None:
             return perf_counter_ns() - self.started
         else:
             return self.stopped - self.started
 
     def elapsed_string(self) -> str:
-        return get_time_string_from_ns(self.elapsed())
+        return human_readable_time_from_ns(self.elapsed())
 
     def avg_elapsed(self, divider: int) -> float:
         return self.elapsed() / divider
 
     def avg_string(self, divider: int) -> str:
-        return get_time_string_from_ns(int(self.avg_elapsed(divider)))
+        return human_readable_time_from_ns(int(self.avg_elapsed(divider)))
 
     def __str__(self):
         return self.avg_string(1)

tools/tools.py

@@ -64,6 +64,25 @@ def human_readable_time_from_delta(delta: datetime.timedelta) -> str:
     return time_str + "%02d" % (delta.seconds % 60)
 
 
+def human_readable_time_from_ns(ns: int) -> str:
+    units = [
+        (1000, 'ns'),
+        (1000, 'µs'),
+        (1000, 'ms'),
+        (60, 's'),
+        (60, 'm'),
+        (60, 'h'),
+        (24, 'd'),
+    ]
+
+    time_parts = []
+    for div, unit in units:
+        ns, p = ns // div, ns % div
+        time_parts.insert(0, "%d%s" % (p, unit))
+        if ns == 0:
+            return ", ".join(time_parts)
+
+
 def cache(func):
     saved = {}