/// <summary>
/// Write data to data point characteristic
/// </summary>
/// <param name="crc32"></param>
/// <param name="file"></param>
/// <param name="device"></param>
/// <param name="MTU"></param>
/// <param name="transferBytes"></param>
/// <param name="remoteOffset"></param>
/// <returns></returns>
private async Task <int> TransferData(IGattCharacteristic packetPoint, CRC32 crc, Stream file, /*int prn = -1,*/ int offsetStart = 0, int offsetEnd = -1, int MTU = 20)
{
const int RESERVED_BYTES = 3;
int bytesWritten = 0;
try
{
int MAX_READ_BYTES = MTU - RESERVED_BYTES;
Debug.WriteLineIf(LogLevelDebug, String.Format("Start of data transfer flen: {0}", file.Length));
file.Seek(offsetStart, SeekOrigin.Begin);
byte[] data = new byte[MAX_READ_BYTES];
for (int packetsSent = 0, offset = offsetStart; ;)
{
int bytesToRead = MAX_READ_BYTES;
if (offsetEnd > -1)
{
int endOffsetDiff = offsetEnd - offset;
if (endOffsetDiff <= 0)
{
break;
}
bytesToRead = Math.Min(bytesToRead, endOffsetDiff);
}
Debug.WriteLineIf(LogLevelDebug, String.Format("Reading {0} bytes from file stream", bytesToRead));
int size = file.Read(data, 0, bytesToRead);
if (size <= 0)
{
break;
}
offset += size;
byte[] pending;
if (size < MAX_READ_BYTES)
{
pending = new byte[size];
Array.Copy(data, pending, size);
}
else
{
pending = data;
}
// Specific for iOS, if no timeout, then sending happens to be blocked
await Task.Delay(1);
await packetPoint.WriteWithoutResponse(pending).Timeout(OperationTimeout);
packetsSent++;
bytesWritten += pending.Length;
crc.Update(pending);
Debug.WriteLineIf(LogLevelDebug, String.Format("### CRC32 Step value, crc: {0} offset:{2} size: {1} packetLocalNo:{3}", crc.Value, pending.Length, offset, packetsSent));
}
Debug.WriteLineIf(LogLevelDebug, String.Format("End of data transfer"));
}
catch (Exception ex)
{
Debug.WriteLineIf(LogLevelDebug, String.Format("Error while transfering data"));
Debug.Write(ex);
}
return(bytesWritten);
}