# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
# -*- coding: utf-8 -*-
from time import perf_counter
from typing import Optional
[docs]class Timer:
"""
A timer which computes the time elapsed since the start/reset of the timer.
"""
def __init__(self) -> None:
self.reset()
[docs] def reset(self) -> None:
"""
Reset the timer.
"""
self._start = perf_counter()
self._paused: Optional[float] = None
self._total_paused = 0
self._count_start = 1
[docs] def pause(self) -> None:
"""
Pause the timer.
"""
if self._paused is not None:
raise ValueError("Trying to pause a Timer that is already paused!")
self._paused = perf_counter()
[docs] def is_paused(self) -> bool:
"""
Returns:
bool: whether the timer is currently paused
"""
return self._paused is not None
[docs] def resume(self) -> None:
"""
Resume the timer.
"""
if self._paused is None:
raise ValueError("Trying to resume a Timer that is not paused!")
self._total_paused += perf_counter() - self._paused
self._paused = None
self._count_start += 1
[docs] def seconds(self) -> float:
"""
Returns:
(float): the total number of seconds since the start/reset of the
timer, excluding the time when the timer is paused.
"""
if self._paused is not None:
end_time: float = self._paused # type: ignore
else:
end_time = perf_counter()
return end_time - self._start - self._total_paused
[docs] def avg_seconds(self) -> float:
"""
Returns:
(float): the average number of seconds between every start/reset and
pause.
"""
return self.seconds() / self._count_start