Repo created

TMessagesProj/jni/voip/webrtc/api/numerics/samples_stats_counter.h

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+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef API_NUMERICS_SAMPLES_STATS_COUNTER_H_
+#define API_NUMERICS_SAMPLES_STATS_COUNTER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "api/array_view.h"
+#include "api/units/timestamp.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/numerics/running_statistics.h"
+
+namespace webrtc {
+
+// This class extends RunningStatistics by providing GetPercentile() method,
+// while slightly adapting the interface.
+class SamplesStatsCounter {
+ public:
+  struct StatsSample {
+    double value;
+    Timestamp time;
+    // Sample's specific metadata.
+    std::map<std::string, std::string> metadata;
+  };
+
+  SamplesStatsCounter();
+  explicit SamplesStatsCounter(size_t expected_samples_count);
+  ~SamplesStatsCounter();
+  SamplesStatsCounter(const SamplesStatsCounter&);
+  SamplesStatsCounter& operator=(const SamplesStatsCounter&);
+  SamplesStatsCounter(SamplesStatsCounter&&);
+  SamplesStatsCounter& operator=(SamplesStatsCounter&&);
+
+  // Adds sample to the stats in amortized O(1) time.
+  void AddSample(double value);
+  void AddSample(StatsSample sample);
+
+  // Adds samples from another counter.
+  void AddSamples(const SamplesStatsCounter& other);
+
+  // Returns if there are any values in O(1) time.
+  bool IsEmpty() const { return samples_.empty(); }
+  // Returns the amount of samples added into counter in O(1) time.
+  int64_t NumSamples() const { return stats_.Size(); }
+
+  // Returns min in O(1) time. This function may not be called if there are no
+  // samples.
+  double GetMin() const {
+    RTC_DCHECK(!IsEmpty());
+    return *stats_.GetMin();
+  }
+  // Returns max in O(1) time. This function may not be called if there are no
+  // samples.
+  double GetMax() const {
+    RTC_DCHECK(!IsEmpty());
+    return *stats_.GetMax();
+  }
+  // Returns sum in O(1) time. This function may not be called if there are
+  // no samples.
+  double GetSum() const {
+    RTC_DCHECK(!IsEmpty());
+    return *stats_.GetSum();
+  }
+  // Returns average in O(1) time. This function may not be called if there are
+  // no samples.
+  double GetAverage() const {
+    RTC_DCHECK(!IsEmpty());
+    return *stats_.GetMean();
+  }
+  // Returns variance in O(1) time. This function may not be called if there are
+  // no samples.
+  double GetVariance() const {
+    RTC_DCHECK(!IsEmpty());
+    return *stats_.GetVariance();
+  }
+  // Returns standard deviation in O(1) time. This function may not be called if
+  // there are no samples.
+  double GetStandardDeviation() const {
+    RTC_DCHECK(!IsEmpty());
+    return *stats_.GetStandardDeviation();
+  }
+  // Returns percentile in O(nlogn) on first call and in O(1) after, if no
+  // additions were done. This function may not be called if there are no
+  // samples.
+  //
+  // `percentile` has to be in [0; 1]. 0 percentile is the min in the array and
+  // 1 percentile is the max in the array.
+  double GetPercentile(double percentile);
+  // Returns array view with all samples added into counter. There are no
+  // guarantees of order, so samples can be in different order comparing to in
+  // which they were added into counter. Also return value will be invalidate
+  // after call to any non const method.
+  rtc::ArrayView<const StatsSample> GetTimedSamples() const { return samples_; }
+  std::vector<double> GetSamples() const {
+    std::vector<double> out;
+    out.reserve(samples_.size());
+    for (const auto& sample : samples_) {
+      out.push_back(sample.value);
+    }
+    return out;
+  }
+
+ private:
+  webrtc_impl::RunningStatistics<double> stats_;
+  std::vector<StatsSample> samples_;
+  bool sorted_ = false;
+};
+
+// Multiply all sample values on `value` and return new SamplesStatsCounter
+// with resulted samples. Doesn't change origin SamplesStatsCounter.
+SamplesStatsCounter operator*(const SamplesStatsCounter& counter, double value);
+inline SamplesStatsCounter operator*(double value,
+                                     const SamplesStatsCounter& counter) {
+  return counter * value;
+}
+// Divide all sample values on `value` and return new SamplesStatsCounter with
+// resulted samples. Doesn't change origin SamplesStatsCounter.
+SamplesStatsCounter operator/(const SamplesStatsCounter& counter, double value);
+
+}  // namespace webrtc
+
+#endif  // API_NUMERICS_SAMPLES_STATS_COUNTER_H_