ZLMediaKit/srt/NackContext.cpp

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2022-06-11 15:11:03 +08:00
#include "NackContext.hpp"
namespace SRT {
void NackContext::update(TimePoint now, std::list<PacketQueue::LostPair> &lostlist) {
for (auto item : lostlist) {
mergeItem(now, item);
}
}
void NackContext::getLostList(
TimePoint now, uint32_t rtt, uint32_t rtt_variance, std::list<PacketQueue::LostPair> &lostlist) {
lostlist.clear();
std::list<uint32_t> tmp_list;
for (auto it = _nack_map.begin(); it != _nack_map.end(); ++it) {
if (!it->second._is_nack) {
tmp_list.push_back(it->first);
it->second._ts = now;
it->second._is_nack = true;
} else {
if (DurationCountMicroseconds(now - it->second._ts) > rtt) {
tmp_list.push_back(it->first);
it->second._ts = now;
}
}
}
tmp_list.sort();
if (tmp_list.empty()) {
return;
}
uint32_t min = *tmp_list.begin();
uint32_t max = *tmp_list.rbegin();
if ((max - min) >= (MAX_SEQ >> 1)) {
while ((max - tmp_list.front()) > (MAX_SEQ >> 1)) {
tmp_list.push_back(tmp_list.front());
tmp_list.pop_front();
}
}
PacketQueue::LostPair lost;
bool finish = true;
for (auto cur = tmp_list.begin(); cur != tmp_list.end(); ++cur) {
if (finish) {
lost.first = *cur;
lost.second = genExpectedSeq(*cur + 1);
finish = false;
} else {
if (lost.second == *cur) {
lost.second = genExpectedSeq(*cur + 1);
} else {
finish = true;
lostlist.push_back(lost);
}
}
}
}
void NackContext::drop(uint32_t seq) {
if (_nack_map.empty())
return;
uint32_t min = _nack_map.begin()->first;
uint32_t max = _nack_map.rbegin()->first;
bool is_cycle = false;
if ((max - min) >= (MAX_SEQ >> 1)) {
is_cycle = true;
}
for (auto it = _nack_map.begin(); it != _nack_map.end();) {
if (!is_cycle) {
// 不回环
if (it->first <= seq) {
it = _nack_map.erase(it);
} else {
it++;
}
} else {
if (it->first <= seq) {
if ((seq - it->first) >= (MAX_SEQ >> 1)) {
WarnL << "cycle seq " << seq << " " << it->first;
it++;
} else {
it = _nack_map.erase(it);
}
} else {
if ((it->first - seq) >= (MAX_SEQ >> 1)) {
it = _nack_map.erase(it);
WarnL << "cycle seq " << seq << " " << it->first;
} else {
it++;
}
}
}
}
}
void NackContext::mergeItem(TimePoint now, PacketQueue::LostPair &item) {
for (uint32_t i = item.first; i < item.second; ++i) {
auto it = _nack_map.find(i);
if (it != _nack_map.end()) {
} else {
NackItem tmp;
tmp._is_nack = false;
_nack_map.emplace(i, tmp);
}
}
}
} // namespace SRT