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samples_stats_counter.h (4742B)

      1 /*
      2 *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
      3 *
      4 *  Use of this source code is governed by a BSD-style license
      5 *  that can be found in the LICENSE file in the root of the source
      6 *  tree. An additional intellectual property rights grant can be found
      7 *  in the file PATENTS.  All contributing project authors may
      8 *  be found in the AUTHORS file in the root of the source tree.
      9 */
     10 
     11 #ifndef API_NUMERICS_SAMPLES_STATS_COUNTER_H_
     12 #define API_NUMERICS_SAMPLES_STATS_COUNTER_H_
     13 
     14 #include <stddef.h>
     15 #include <stdint.h>
     16 
     17 #include <map>
     18 #include <string>
     19 #include <vector>
     20 
     21 #include "api/array_view.h"
     22 #include "api/units/timestamp.h"
     23 #include "rtc_base/checks.h"
     24 #include "rtc_base/numerics/running_statistics.h"
     25 
     26 namespace webrtc {
     27 
     28 // This class extends RunningStatistics by providing GetPercentile() method,
     29 // while slightly adapting the interface.
     30 class SamplesStatsCounter {
     31 public:
     32  struct StatsSample {
     33    double value;
     34    Timestamp time;
     35    // Sample's specific metadata.
     36    std::map<std::string, std::string> metadata;
     37  };
     38 
     39  SamplesStatsCounter();
     40  explicit SamplesStatsCounter(size_t expected_samples_count);
     41  ~SamplesStatsCounter();
     42  SamplesStatsCounter(const SamplesStatsCounter&);
     43  SamplesStatsCounter& operator=(const SamplesStatsCounter&);
     44  SamplesStatsCounter(SamplesStatsCounter&&);
     45  SamplesStatsCounter& operator=(SamplesStatsCounter&&);
     46 
     47  // Adds sample to the stats in amortized O(1) time.
     48  [[deprecated("Use AddSample(StatsSample) instead.")]]
     49  void AddSample(double value);
     50  void AddSample(StatsSample sample);
     51 
     52  // Adds samples from another counter.
     53  void AddSamples(const SamplesStatsCounter& other);
     54 
     55  // Returns if there are any values in O(1) time.
     56  bool IsEmpty() const { return samples_.empty(); }
     57  // Returns the amount of samples added into counter in O(1) time.
     58  int64_t NumSamples() const { return stats_.Size(); }
     59 
     60  // Returns min in O(1) time. This function may not be called if there are no
     61  // samples.
     62  double GetMin() const {
     63    RTC_DCHECK(!IsEmpty());
     64    return *stats_.GetMin();
     65  }
     66  // Returns max in O(1) time. This function may not be called if there are no
     67  // samples.
     68  double GetMax() const {
     69    RTC_DCHECK(!IsEmpty());
     70    return *stats_.GetMax();
     71  }
     72  // Returns sum in O(1) time. This function may not be called if there are
     73  // no samples.
     74  double GetSum() const {
     75    RTC_DCHECK(!IsEmpty());
     76    return *stats_.GetSum();
     77  }
     78  // Returns average in O(1) time. This function may not be called if there are
     79  // no samples.
     80  double GetAverage() const {
     81    RTC_DCHECK(!IsEmpty());
     82    return *stats_.GetMean();
     83  }
     84  // Returns variance in O(1) time. This function may not be called if there are
     85  // no samples.
     86  double GetVariance() const {
     87    RTC_DCHECK(!IsEmpty());
     88    return *stats_.GetVariance();
     89  }
     90  // Returns standard deviation in O(1) time. This function may not be called if
     91  // there are no samples.
     92  double GetStandardDeviation() const {
     93    RTC_DCHECK(!IsEmpty());
     94    return *stats_.GetStandardDeviation();
     95  }
     96  // Returns percentile in O(nlogn) on first call and in O(1) after, if no
     97  // additions were done. This function may not be called if there are no
     98  // samples.
     99  //
    100  // `percentile` has to be in [0; 1]. 0 percentile is the min in the array and
    101  // 1 percentile is the max in the array.
    102  double GetPercentile(double percentile);
    103  // Returns array view with all samples added into counter. There are no
    104  // guarantees of order, so samples can be in different order comparing to in
    105  // which they were added into counter. Also return value will be invalidate
    106  // after call to any non const method.
    107  ArrayView<const StatsSample> GetTimedSamples() const { return samples_; }
    108  std::vector<double> GetSamples() const {
    109    std::vector<double> out;
    110    out.reserve(samples_.size());
    111    for (const auto& sample : samples_) {
    112      out.push_back(sample.value);
    113    }
    114    return out;
    115  }
    116 
    117 private:
    118  webrtc_impl::RunningStatistics<double> stats_;
    119  std::vector<StatsSample> samples_;
    120  bool sorted_ = false;
    121 };
    122 
    123 // Multiply all sample values on `value` and return new SamplesStatsCounter
    124 // with resulted samples. Doesn't change origin SamplesStatsCounter.
    125 SamplesStatsCounter operator*(const SamplesStatsCounter& counter, double value);
    126 inline SamplesStatsCounter operator*(double value,
    127                                     const SamplesStatsCounter& counter) {
    128  return counter * value;
    129 }
    130 // Divide all sample values on `value` and return new SamplesStatsCounter with
    131 // resulted samples. Doesn't change origin SamplesStatsCounter.
    132 SamplesStatsCounter operator/(const SamplesStatsCounter& counter, double value);
    133 
    134 }  // namespace webrtc
    135 
    136 #endif  // API_NUMERICS_SAMPLES_STATS_COUNTER_H_