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 RTC_BASE_NUMERICS_SAMPLE_COUNTER_H_
12 #define RTC_BASE_NUMERICS_SAMPLE_COUNTER_H_
13 
14 #include <stdint.h>
15 
16 #include "absl/types/optional.h"
17 
18 namespace rtc {
19 
20 // Simple utility class for counting basic statistics (max./avg./variance) on
21 // stream of samples.
22 class SampleCounter {
23  public:
24   SampleCounter();
25   ~SampleCounter();
26   void Add(int sample);
27   absl::optional<int> Avg(int64_t min_required_samples) const;
28   absl::optional<int> Max() const;
29   absl::optional<int64_t> Sum(int64_t min_required_samples) const;
30   int64_t NumSamples() const;
31   void Reset();
32   // Adds all the samples from the |other| SampleCounter as if they were all
33   // individually added using |Add(int)| method.
34   void Add(const SampleCounter& other);
35 
36  protected:
37   int64_t sum_ = 0;
38   int64_t num_samples_ = 0;
39   absl::optional<int> max_;
40 };
41 
42 class SampleCounterWithVariance : public SampleCounter {
43  public:
44   SampleCounterWithVariance();
45   ~SampleCounterWithVariance();
46   void Add(int sample);
47   absl::optional<int64_t> Variance(int64_t min_required_samples) const;
48   void Reset();
49   // Adds all the samples from the |other| SampleCounter as if they were all
50   // individually added using |Add(int)| method.
51   void Add(const SampleCounterWithVariance& other);
52 
53  private:
54   int64_t sum_squared_ = 0;
55 };
56 
57 }  // namespace rtc
58 #endif  // RTC_BASE_NUMERICS_SAMPLE_COUNTER_H_
59