Channel[] ReadChannels(ParityStreamReader reader, int channelIdOffset, int numberOfChannels)
{
var channels = new Channel[numberOfChannels];
for (var i = 0; i < numberOfChannels; ++i)
{
var channelData = reader.ReadUntil(',');
var channelState = ' ';
var channelValue = 0.0;
if (channelData[0] != ' ' && (channelData[0] < '0' || channelData[0] > '9'))
{
// There is something other than a number in the first character
channelState = channelData[0];
double.TryParse(channelData.AsSpan().Slice(1), out channelValue);
}
else
{
// Just a number
double.TryParse(channelData, out channelValue);
}
channels[i] = new Channel
{
Id = i + channelIdOffset,
Value = new ChannelValue
{
State = channelState,
Value = channelValue,
ParityError = false,
},
};
}
return(channels);
}
/// <inheritdoc/>
public void BeginParse(Stream stream, Action <Channel> callback, Action <Exception> exceptionOccurred = null)
{
try
{
var reader = new ParityStreamReader(stream);
// Keep track of the blocks
var lastSeenBlock = -1;
var channelIdOffset = 0;
for (;;)
{
reader.SkipTill(StartBlock);
var blockNumber = reader.ReadAsciiInt(3);
var numberOfChannels = reader.ReadAsciiInt(3);
var outOfOrderBlock = false;
if (blockNumber == 0)
{
lastSeenBlock = 0;
channelIdOffset = 0;
}
else if (blockNumber == lastSeenBlock + 1)
{
lastSeenBlock = blockNumber;
}
else
{
outOfOrderBlock = true;
_logger.Warning($"An out of order block '{blockNumber}' was detected, data will have to be thrown away.");
}
_logger.Information($"Handling block '{blockNumber}' with '{numberOfChannels}' channels");
var channels = ReadChannels(reader, channelIdOffset, numberOfChannels);
var calculatedParity = reader.Parity;
if (reader.ReadByte() != '*')
{
throw new InvalidDataException("Expected '*' after all channel data");
}
var transmittedParity = reader.ReadAsciiHexByte();
if (calculatedParity != transmittedParity)
{
_logger.Warning($"A parity error was detected while reading block '{blockNumber}'.");
}
reader.ReadByte(); // There should be an end-of-text here, but there's no need to check
// Transmit the data if the block was in order
if (!outOfOrderBlock)
{
for (var i = 0; i < numberOfChannels; ++i)
{
channels[i].Value.ParityError = calculatedParity != transmittedParity;
callback(channels[i]);
}
}
// Keep track of channels seen
channelIdOffset += numberOfChannels;
}
}
catch (Exception ex)
{
_logger.Error(ex, "Error while parsing");
if (exceptionOccurred != null)
{
exceptionOccurred(ex);
}
}
}