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1 /* | 1 /* |
2 * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. | 2 * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license | 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 | 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 | 6 * tree. An additional intellectual property rights grant can be found |
7 * in the file PATENTS. All contributing project authors may | 7 * in the file PATENTS. All contributing project authors may |
8 * be found in the AUTHORS file in the root of the source tree. | 8 * be found in the AUTHORS file in the root of the source tree. |
9 */ | 9 */ |
10 | 10 |
11 #ifndef WEBRTC_BASE_RATE_STATISTICS_H_ | 11 #ifndef WEBRTC_BASE_RATE_STATISTICS_H_ |
12 #define WEBRTC_BASE_RATE_STATISTICS_H_ | 12 #define WEBRTC_BASE_RATE_STATISTICS_H_ |
13 | 13 |
14 #include <memory> | 14 #include <memory> |
15 | 15 |
16 #include "webrtc/base/optional.h" | 16 #include "webrtc/base/optional.h" |
17 #include "webrtc/typedefs.h" | 17 #include "webrtc/typedefs.h" |
18 | 18 |
19 namespace webrtc { | 19 namespace webrtc { |
20 | 20 |
21 class RateStatistics { | 21 class RateStatistics { |
22 public: | 22 public: |
23 static constexpr float kBpsScale = 8000.0f; | |
24 | |
25 // max_window_size_ms = Maximum window size in ms for the rate estimation. | 23 // max_window_size_ms = Maximum window size in ms for the rate estimation. |
26 // Initial window size is set to this, but may be changed | 24 // Initial window size is set to this, but may be changed |
27 // to something lower by calling SetWindowSize(). | 25 // to something lower by calling SetWindowSize(). |
28 // scale = coefficient to convert counts/ms to desired unit | 26 // scale = coefficient to convert counts/ms to desired units, |
29 // ex: kBpsScale (8000) for bits/s if count represents bytes. | 27 // ex: if counts represents bytes, use 8*1000 to go to bits/s |
30 RateStatistics(int64_t max_window_size_ms, float scale); | 28 RateStatistics(int64_t max_window_size_ms, float scale); |
31 ~RateStatistics(); | 29 ~RateStatistics(); |
32 | 30 |
33 // Reset instance to original state. | |
34 void Reset(); | 31 void Reset(); |
35 | |
36 // Update rate with a new data point, moving averaging window as needed. | |
37 void Update(size_t count, int64_t now_ms); | 32 void Update(size_t count, int64_t now_ms); |
38 | 33 rtc::Optional<uint32_t> Rate(int64_t now_ms); |
39 // Note that despite this being a const method, it still updates the internal | |
40 // state (moves averaging window), but it doesn't make any alterations that | |
41 // are observable from the other methods, as long as supplied timestamps are | |
42 // from a monotonic clock. Ie, it doesn't matter if this call moves the | |
43 // window, since any subsequent call to Update or Rate would still have moved | |
44 // the window as much or more. | |
45 rtc::Optional<uint32_t> Rate(int64_t now_ms) const; | |
46 | |
47 // Update the size of the averaging window. The maximum allowed value for | |
48 // window_size_ms is max_window_size_ms as supplied in the constructor. | |
49 bool SetWindowSize(int64_t window_size_ms, int64_t now_ms); | 34 bool SetWindowSize(int64_t window_size_ms, int64_t now_ms); |
50 | 35 |
51 private: | 36 private: |
52 void EraseOld(int64_t now_ms); | 37 void EraseOld(int64_t now_ms); |
53 bool IsInitialized() const; | 38 bool IsInitialized(); |
54 | 39 |
55 // Counters are kept in buckets (circular buffer), with one bucket | 40 // Counters are kept in buckets (circular buffer), with one bucket |
56 // per millisecond. | 41 // per millisecond. |
57 struct Bucket { | 42 struct Bucket { |
58 size_t sum; // Sum of all samples in this bucket. | 43 size_t sum; // Sum of all samples in this bucket. |
59 size_t samples; // Number of samples in this bucket. | 44 size_t samples; // Number of samples in this bucket. |
60 }; | 45 }; |
61 std::unique_ptr<Bucket[]> buckets_; | 46 std::unique_ptr<Bucket[]> buckets_; |
62 | 47 |
63 // Total count recorded in buckets. | 48 // Total count recorded in buckets. |
(...skipping 11 matching lines...) Expand all Loading... |
75 // To convert counts/ms to desired units | 60 // To convert counts/ms to desired units |
76 const float scale_; | 61 const float scale_; |
77 | 62 |
78 // The window sizes, in ms, over which the rate is calculated. | 63 // The window sizes, in ms, over which the rate is calculated. |
79 const int64_t max_window_size_ms_; | 64 const int64_t max_window_size_ms_; |
80 int64_t current_window_size_ms_; | 65 int64_t current_window_size_ms_; |
81 }; | 66 }; |
82 } // namespace webrtc | 67 } // namespace webrtc |
83 | 68 |
84 #endif // WEBRTC_BASE_RATE_STATISTICS_H_ | 69 #endif // WEBRTC_BASE_RATE_STATISTICS_H_ |
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