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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CC_TEST_LAP_TIMER_H_
      6 #define CC_TEST_LAP_TIMER_H_
      7 
      8 #include "base/time/time.h"
      9 
     10 namespace cc {
     11 
     12 // LapTimer is used to calculate average times per "Lap" in perf tests.
     13 // Current() reports the time since the last call to Start().
     14 // Store() adds the time since the last call to Start() to the accumulator, and
     15 // resets the start time to now. Stored() returns the accumulated time.
     16 // NextLap increments the lap counter, used in counting the per lap averages.
     17 // If you initialize the LapTimer with a non zero warmup_laps, it will ignore
     18 // the times for that many laps at the start.
     19 // If you set the time_limit then you can use HasTimeLimitExpired() to see if
     20 // the current accumulated time has crossed that threshold, with an optimization
     21 // that it only tests this every check_interval laps.
     22 class LapTimer {
     23  public:
     24   LapTimer(int warmup_laps, base::TimeDelta time_limit, int check_interval);
     25   // Resets the timer back to it's starting state.
     26   void Reset();
     27   // Sets the start point to now.
     28   void Start();
     29   // Returns true if there are no more warmup laps to do.
     30   bool IsWarmedUp();
     31   // Advance the lap counter and update the accumulated time.
     32   // The accumulated time is only updated every check_interval laps.
     33   // If accumulating then the start point will also be updated.
     34   void NextLap();
     35   // Returns true if the stored time has exceeded the time limit specified.
     36   // May cause a call to Store().
     37   bool HasTimeLimitExpired();
     38   // The average milliseconds per lap.
     39   float MsPerLap();
     40   // The number of laps per second.
     41   float LapsPerSecond();
     42   // The number of laps recorded.
     43   int NumLaps();
     44 
     45  private:
     46   base::TimeTicks start_time_;
     47   base::TimeDelta accumulator_;
     48   int num_laps_;
     49   int warmup_laps_;
     50   int remaining_warmups_;
     51   base::TimeDelta time_limit_;
     52   int check_interval_;
     53   bool accumulated_;
     54 
     55   DISALLOW_COPY_AND_ASSIGN(LapTimer);
     56 };
     57 
     58 }  // namespace cc
     59 
     60 #endif  // CC_TEST_LAP_TIMER_H_
     61