/// <summary>
/// Gets one or more packets from the capture file, beginning at the specified packet index
/// </summary>
/// <param name="index">the index of the first record in the packet index file</param>
/// <param name="count">the number of packets to collect</param>
/// <returns>a new packet collection object</returns>
public PacketCollection GetPackets(long index, int count = 1)
{
PacketCollection collection = new PacketCollection();
long curr = index;
for (int k = 0; k < count; k++)
{
_filestream.Seek(curr, SeekOrigin.Begin);
byte[] header = new byte[16];
_filestream.Read(header, 0, 16);
DateTime time = new DateTime(1970, 1, 1, 0, 0, 0).AddSeconds(BitConverter.ToInt32(header, 0));
time = time.AddMilliseconds(BitConverter.ToInt32(header, 4));
int incl = BitConverter.ToInt32(header, 8);
int orig = BitConverter.ToInt32(header, 12);
byte[] payload = new byte[incl];
_filestream.Read(payload, 0, incl);
collection.AddPacket(new Packet(time, orig, payload));
curr += incl + 16;
}
return(collection);
}
public void Merge(PacketCollection collection)
{
foreach (var packet in collection.Collection)
{
_packetCollection.Add(packet);
}
}
/// <summary>
/// Gets the amount of elapsed time between packets at index1 and index2
/// </summary>
/// <param name="index1">the index of the packet starting the time span</param>
/// <param name="index2">the index of the packet concluding the time span</param>
/// <returns>the time span as a TimeSpan object</returns>
public TimeSpan GetTimeSpan(long index1, long index2)
{
PacketCollection packets = GetPackets(index1);
packets.Merge(GetPackets(index2));
return(packets.Collection[1].ArrivalTime.Subtract(packets.Collection[0].ArrivalTime));
}