cc/base/rolling_time_delta_history.h

   1 // Copyright 2014 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_BASE_ROLLING_TIME_DELTA_HISTORY_H_
   6 #define CC_BASE_ROLLING_TIME_DELTA_HISTORY_H_
   7
   8 #include <deque>
   9 #include <set>
  10
  11 #include "base/time/time.h"
  12 #include "cc/base/cc_export.h"
  13
  14 namespace cc {
  15
  16 // Stores a limited number of samples. When the maximum size is reached, each
  17 // insertion results in the deletion of the oldest remaining sample.
  18 class CC_EXPORT RollingTimeDeltaHistory {
  19  public:
  20   explicit RollingTimeDeltaHistory(size_t max_size);
  21
  22   ~RollingTimeDeltaHistory();
  23
  24   void InsertSample(base::TimeDelta time);
  25
  26   size_t SampleCount();
  27
  28   void Clear();
  29
  30   // Returns the smallest sample that is greater than or equal to the specified
  31   // percent of samples. If there aren't any samples, returns base::TimeDelta().
  32   base::TimeDelta Percentile(double percent) const;
  33
  34  private:
  35   typedef std::multiset<base::TimeDelta> TimeDeltaMultiset;
  36
  37   TimeDeltaMultiset sample_set_;
  38   std::deque<TimeDeltaMultiset::iterator> chronological_sample_deque_;
  39   size_t max_size_;
  40
  41   DISALLOW_COPY_AND_ASSIGN(RollingTimeDeltaHistory);
  42 };
  43
  44 }  // namespace cc
  45
  46 #endif  // CC_BASE_ROLLING_TIME_DELTA_HISTORY_H_