////  SentPacketHistory.cpp//  libraries/networking/src////  Created by Yixin Wang on 6/5/2014////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html// #include "SentPacketHistory.h" #include <limits> #include <QDebug> #include "NetworkLogging.h"#include "NLPacket.h" SentPacketHistory::SentPacketHistory(int size)    : _sentPackets(size),    _newestSequenceNumber(std::numeric_limits<uint16_t>::max()){ } void SentPacketHistory::untrackedPacketSent(uint16_t sequenceNumber) {    // check if given seq number has the expected value.  if not, something's wrong with    // the code calling this function    uint16_t expectedSequenceNumber = _newestSequenceNumber + (uint16_t)1;    if (sequenceNumber != expectedSequenceNumber) {        qCDebug(networking) << "Unexpected sequence number passed to SentPacketHistory::packetSent()!"            << "Expected:" << expectedSequenceNumber << "Actual:" << sequenceNumber;    }    _newestSequenceNumber = sequenceNumber;} void SentPacketHistory::packetSent(uint16_t sequenceNumber, const NLPacket& packet) {    untrackedPacketSent(sequenceNumber);     QWriteLocker locker(&_packetsLock);    _sentPackets.insert(NLPacket::createCopy(packet));} const NLPacket* SentPacketHistory::getPacket(uint16_t sequenceNumber) const {     const int UINT16_RANGE = std::numeric_limits<uint16_t>::max() + 1;     // if sequenceNumber > _newestSequenceNumber, assume sequenceNumber is from before the most recent rollover    // correct the diff so that it correctly represents how far back in the history sequenceNumber is    int seqDiff = (int)_newestSequenceNumber - (int)sequenceNumber;    if (seqDiff < 0) {        seqDiff += UINT16_RANGE;    }        QReadLocker locker(&_packetsLock);    auto packet = _sentPackets.get(seqDiff);    if (packet) {        return packet->get();    }    return nullptr;}