1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
/*
* Copyright (c) 2015 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.
*/
#include "modules/rtp_rtcp/source/packet_loss_stats.h"
#include <cstdint>
#include <iterator>
#include <set>
#include <vector>
#include "rtc_base/checks.h"
namespace webrtc {
namespace {
// After this many packets are added, adding additional packets will cause the
// oldest packets to be pruned from the buffer.
constexpr int kBufferSize = 100;
} // namespace
PacketLossStats::PacketLossStats()
: single_loss_historic_count_(0),
multiple_loss_historic_event_count_(0),
multiple_loss_historic_packet_count_(0) {}
PacketLossStats::~PacketLossStats() = default;
void PacketLossStats::AddLostPacket(uint16_t sequence_number) {
// Detect sequence number wrap around.
if (!lost_packets_buffer_.empty() &&
static_cast<int>(*(lost_packets_buffer_.rbegin())) - sequence_number >
0x8000) {
// The buffer contains large numbers and this is a small number.
lost_packets_wrapped_buffer_.insert(sequence_number);
} else {
lost_packets_buffer_.insert(sequence_number);
}
if (lost_packets_wrapped_buffer_.size() + lost_packets_buffer_.size() >
kBufferSize ||
(!lost_packets_wrapped_buffer_.empty() &&
*(lost_packets_wrapped_buffer_.rbegin()) > 0x4000)) {
PruneBuffer();
}
}
int PacketLossStats::GetSingleLossCount() const {
int single_loss_count, unused1, unused2;
ComputeLossCounts(&single_loss_count, &unused1, &unused2);
return single_loss_count;
}
int PacketLossStats::GetMultipleLossEventCount() const {
int event_count, unused1, unused2;
ComputeLossCounts(&unused1, &event_count, &unused2);
return event_count;
}
int PacketLossStats::GetMultipleLossPacketCount() const {
int packet_count, unused1, unused2;
ComputeLossCounts(&unused1, &unused2, &packet_count);
return packet_count;
}
void PacketLossStats::ComputeLossCounts(
int* out_single_loss_count,
int* out_multiple_loss_event_count,
int* out_multiple_loss_packet_count) const {
*out_single_loss_count = single_loss_historic_count_;
*out_multiple_loss_event_count = multiple_loss_historic_event_count_;
*out_multiple_loss_packet_count = multiple_loss_historic_packet_count_;
if (lost_packets_buffer_.empty()) {
RTC_DCHECK(lost_packets_wrapped_buffer_.empty());
return;
}
uint16_t last_num = 0;
int sequential_count = 0;
std::vector<const std::set<uint16_t>*> buffers;
buffers.push_back(&lost_packets_buffer_);
buffers.push_back(&lost_packets_wrapped_buffer_);
for (const auto* buffer : buffers) {
for (auto it = buffer->begin(); it != buffer->end(); ++it) {
uint16_t current_num = *it;
if (sequential_count > 0 && current_num != ((last_num + 1) & 0xFFFF)) {
if (sequential_count == 1) {
(*out_single_loss_count)++;
} else {
(*out_multiple_loss_event_count)++;
*out_multiple_loss_packet_count += sequential_count;
}
sequential_count = 0;
}
sequential_count++;
last_num = current_num;
}
}
if (sequential_count == 1) {
(*out_single_loss_count)++;
} else if (sequential_count > 1) {
(*out_multiple_loss_event_count)++;
*out_multiple_loss_packet_count += sequential_count;
}
}
void PacketLossStats::PruneBuffer() {
// Remove the oldest lost packet and any contiguous packets and move them
// into the historic counts.
auto it = lost_packets_buffer_.begin();
uint16_t last_removed = 0;
int remove_count = 0;
// Count adjacent packets and continue counting if it is wrap around by
// swapping in the wrapped buffer and letting our value wrap as well.
while (remove_count == 0 || (!lost_packets_buffer_.empty() &&
*it == ((last_removed + 1) & 0xFFFF))) {
last_removed = *it;
remove_count++;
auto to_erase = it++;
lost_packets_buffer_.erase(to_erase);
if (lost_packets_buffer_.empty()) {
lost_packets_buffer_.swap(lost_packets_wrapped_buffer_);
it = lost_packets_buffer_.begin();
}
}
if (remove_count > 1) {
multiple_loss_historic_event_count_++;
multiple_loss_historic_packet_count_ += remove_count;
} else {
single_loss_historic_count_++;
}
// Continue pruning if the wrapped buffer is beyond a threshold and there are
// things left in the pre-wrapped buffer.
if (!lost_packets_wrapped_buffer_.empty() &&
*(lost_packets_wrapped_buffer_.rbegin()) > 0x4000) {
PruneBuffer();
}
}
} // namespace webrtc
|
