fix timelatency not take effect and avoid buffer is liner avoid cycle

srt/PacketSendQueue.cpp

@@ -0,0 +1,77 @@
+#include "PacketSendQueue.hpp"
+
+namespace SRT {
+
+PacketSendQueue::PacketSendQueue(uint32_t max_size, uint32_t lantency)
+    : _pkt_cap(max_size)
+    , _pkt_lantency(lantency) {}
+bool PacketSendQueue::drop(uint32_t num) {
+    decltype(_pkt_cache.begin()) it;
+    for (it = _pkt_cache.begin(); it != _pkt_cache.end(); ++it) {
+        if ((*it)->packet_seq_number == num) {
+            break;
+        }
+    }
+    if (it != _pkt_cache.end()) {
+        _pkt_cache.erase(_pkt_cache.begin(), it);
+    }
+    return true;
+}
+bool PacketSendQueue::inputPacket(DataPacket::Ptr pkt) {
+    _pkt_cache.push_back(pkt);
+    while (_pkt_cache.size() > _pkt_cap) {
+        _pkt_cache.pop_front();
+    }
+    while (timeLantency() > _pkt_lantency) {
+        _pkt_cache.pop_front();
+    }
+    return true;
+}
+
+std::list<DataPacket::Ptr> PacketSendQueue::findPacketBySeq(uint32_t start, uint32_t end) {
+    std::list<DataPacket::Ptr> re;
+    decltype(_pkt_cache.begin()) it;
+    for (it = _pkt_cache.begin(); it != _pkt_cache.end(); ++it) {
+        if ((*it)->packet_seq_number == start) {
+            break;
+        }
+    }
+
+    if (start == end) {
+        if (it != _pkt_cache.end()) {
+            re.push_back(*it);
+        }
+        return re;
+    }
+
+    for (; it != _pkt_cache.end(); ++it) {
+        re.push_back(*it);
+        if ((*it)->packet_seq_number == end) {
+            break;
+        }
+    }
+    return re;
+}
+
+uint32_t PacketSendQueue::timeLantency() {
+    if (_pkt_cache.empty()) {
+        return 0;
+    }
+    auto first = _pkt_cache.front()->timestamp;
+    auto last = _pkt_cache.back()->timestamp;
+    uint32_t dur;
+
+    if (last > first) {
+        dur = last - first;
+    } else {
+        dur = first - last;
+    }
+    if (dur > (0x01 << 31)) {
+        TraceL << "cycle timeLantency " << dur;
+        dur = 0xffffffff - dur;
+    }
+
+    return dur;
+}
+
+} // namespace SRT