/// <summary>
/// This method is based upon increasing the MaxInfoFrames in the MSTP.
/// In Bacnet/IP this will have bad effect due to the retries
/// </summary>
public void DownloadFileByAsync(BacnetClient comm, BacnetAddress adr, BacnetObjectId object_id, string filename, Action <int> progress_action)
{
Cancel = false;
//open file
System.IO.FileStream fs = null;
try
{
fs = System.IO.File.OpenWrite(filename);
}
catch (Exception ex)
{
throw new System.IO.IOException("Couldn't open file", ex);
}
uint max_count = (uint)comm.GetFileBufferMaxSize();
BacnetAsyncResult[] transfers = new BacnetAsyncResult[50];
byte old_max_info_frames = comm.Transport.MaxInfoFrames;
comm.Transport.MaxInfoFrames = 50; //increase max_info_frames so that we can occupy line more. This might be against 'standard'
try
{
int position = 0;
bool eof = false;
while (!eof && !Cancel)
{
//start many async transfers
for (int i = 0; i < transfers.Length; i++)
{
transfers[i] = (BacnetAsyncResult)comm.BeginReadFileRequest(adr, object_id, position + i * (int)max_count, max_count, false);
}
//wait for all transfers to finish
int current = 0;
int retries = comm.Retries;
while (current < transfers.Length)
{
if (!transfers[current].WaitForDone(comm.Timeout))
{
if (--retries > 0)
{
transfers[current].Resend();
continue;
}
else
{
throw new System.IO.IOException("Couldn't read file");
}
}
retries = comm.Retries;
uint count;
byte[] file_buffer;
int file_buffer_offset;
Exception ex;
comm.EndReadFileRequest(transfers[current], out count, out position, out eof, out file_buffer, out file_buffer_offset, out ex);
transfers[current] = null;
if (ex != null)
{
throw ex;
}
if (count > 0)
{
//write to file
fs.Position = position;
fs.Write(file_buffer, file_buffer_offset, (int)count);
position += (int)count;
if (progress_action != null)
{
progress_action(position);
}
}
current++;
}
}
}
finally
{
fs.Close();
comm.Transport.MaxInfoFrames = old_max_info_frames;
}
}