public override async Task SendRequest(ReqType reqType, uint seq, byte[] plBuff, int offset, int len)
{
try
{
if (len > config.CMD_MAX_PLSZ)
{
throw new ArgumentException("len > CMD_MAX_PLSZ", nameof(len));
}
//write sequence number
int pos = config.CMD_HDR_SIZE;
int seqLen = 0;
if (seq > 0)
{
if (config.CMD_SEQ_SIZE == 4)
{
sendBuff[pos++] = (byte)(seq & 0xFF);
sendBuff[pos++] = (byte)((seq >> 8) & 0xFF);
sendBuff[pos++] = (byte)((seq >> 16) & 0xFF);
sendBuff[pos++] = (byte)((seq >> 24) & 0xFF);
}
else
{
throw new Exception("config.CMD_SEQ_SIZE != 4");
}
seqLen = config.CMD_SEQ_SIZE;
}
else
{
len = 0;
}
//write payload
Buffer.BlockCopy(plBuff, offset, sendBuff, pos, len);
pos += len;
sendBuff[0] = (byte)((int)reqType | (len + seqLen + config.CMD_CRC_SIZE));
//write crc
int testLen = len + seqLen + config.CMD_HDR_SIZE;
sendBuff[testLen] = CRC8.Calculate(sendBuff, 0, testLen);
//send data
using (var cts = new CancellationTokenSource())
{
cts.CancelAfter(UseCommitTimeout?config.COMMIT_TIMEOUT:config.CMD_TIMEOUT);
await link.WriteAsync(sendBuff, 0, testLen + config.CMD_CRC_SIZE, cts.Token);
}
}
catch (TaskCanceledException ex)
{
throw new TimeoutException("SendRequest was timed out", ex);
}
}
public override async Task <Answer> ReceiveAnswer()
{
try
{
int bRead = 0;
using (var cts = new CancellationTokenSource())
{
cts.CancelAfter(UseCommitTimeout?config.COMMIT_TIMEOUT:config.CMD_TIMEOUT);
bRead = await link.ReadAsync(recvBuff, 0, 1, cts.Token);
if (bRead != 1)
{
throw new NotSupportedException("Stream has reached EOF and cannot receive data");
}
}
int remSz = recvBuff[0] & config.CMD_SIZE_MASK;
if (remSz < config.CMD_MIN_REMSZ || remSz > config.CMD_MAX_REMSZ)
{
return(Answer.Invalid);
}
if (!Enum.TryParse <AnsType>((recvBuff[0] & config.ANS_ALL_MASK).ToString(), out AnsType ans))
{
return(Answer.Invalid);
}
//calculate plSize
var plSize = remSz - config.CMD_CRC_SIZE;
switch (ans)
{
case AnsType.Ok:
case AnsType.Pong:
if (plSize != config.CMD_SEQ_SIZE)
{
return(Answer.Invalid);
}
break;
case AnsType.DataMarker:
if (plSize != config.CMD_SEQ_SIZE + 1)
{
return(Answer.Invalid);
}
break;
case AnsType.Data:
if (plSize < config.CMD_SEQ_SIZE)
{
return(Answer.Invalid);
}
break;
case AnsType.Resync:
break;
default:
return(Answer.Invalid);
}
var rem = remSz;
using (var cts = new CancellationTokenSource())
{
cts.CancelAfter(UseCommitTimeout?config.COMMIT_TIMEOUT:config.CMD_TIMEOUT);
while (rem > 0)
{
rem -= await link.ReadAsync(recvBuff, config.CMD_HDR_SIZE + (remSz - rem), rem, cts.Token);
}
}
//verify CRC
var testSz = config.CMD_HDR_SIZE + remSz - 1;
if (recvBuff[testSz] != CRC8.Calculate(recvBuff, 0, testSz))
{
return(Answer.Invalid);
}
//decode sequence number
uint seq = 0;
var seqPos = config.CMD_HDR_SIZE;
int dataSize = 0;
if (plSize >= config.CMD_SEQ_SIZE)
{
if (config.CMD_SEQ_SIZE == 4)
{
seq = unchecked ((uint)(recvBuff[seqPos] | recvBuff[seqPos + 1] << 8 | recvBuff[seqPos + 2] << 16 | recvBuff[seqPos + 3] << 24));
}
else
{
throw new Exception("config.CMD_SEQ_SIZE != 4");
}
dataSize = plSize - config.CMD_SEQ_SIZE;
}
var dataPos = (dataSize > 0) ? config.CMD_HDR_SIZE + config.CMD_SEQ_SIZE : 0;
return(new Answer(ans, seq, recvBuff, dataPos, dataSize));
}
catch (Exception ex) when(ex is TaskCanceledException || ex is TimeoutException)
{
throw new TimeoutException("ReceiveAnswer was timed out", ex);
}
}