private void ParserOnParserError(NmeaSinkAndSource source, string message, NmeaError errorCode)
{
if (errorCode == NmeaError.PortClosed)
{
Task t = Task.Run(() =>
{
lock (_lock)
{
_activeParsers.Remove(source);
}
// Can't do this synchronously, as it would cause a deadlock
source.StopDecode();
});
_serverTasks.Enqueue(t);
_serverControlEvent.Set();
}
FireOnParserError(message, errorCode);
}
/// <summary>
/// Reads NMEA0183 talker sentence from provided string
/// </summary>
/// <param name="sentence">NMEA0183 talker sentence</param>
/// <param name="expectedTalkerId">If this is not TalkerId.Any, only messages with this talker id are parsed,
/// all others are ignored. This reduces workload if a source acts as repeater, but the repeated messages are not needed.</param>
/// <param name="errorCode">Returns an error code, if the parsing failed</param>
/// <returns>TalkerSentence instance, or null in case of an error</returns>
/// <remarks><paramref name="sentence"/> does not include new line characters</remarks>
public static TalkerSentence?FromSentenceString(string sentence, TalkerId expectedTalkerId, out NmeaError errorCode)
{
// $XXY, ...
const int sentenceHeaderMinLength = 4;
// http://www.tronico.fi/OH6NT/docs/NMEA0183.pdf page 2
// defines this as 80 + 1 (for $), but we don't really care if it is something within a reasonable limit.
const int MaxSentenceLength = 256;
if (sentence == null)
{
throw new ArgumentNullException(nameof(sentence));
}
if (sentence.Length < sentenceHeaderMinLength)
{
errorCode = NmeaError.MessageToShort;
return(null);
}
if (sentence.Length > MaxSentenceLength)
{
errorCode = NmeaError.MessageToLong;
return(null);
}
if (sentence[0] != '$' && sentence[0] != '!')
{
// Valid sentences start with $ or ! (for the AIS sentences)
errorCode = NmeaError.NoSyncByte;
return(null);
}
TalkerId talkerId = new TalkerId(sentence[1], sentence[2]);
if (expectedTalkerId != TalkerId.Any && expectedTalkerId != talkerId)
{
errorCode = NmeaError.None;
return(null);
}
int firstComma = sentence.IndexOf(',', 1);
if (firstComma == -1)
{
errorCode = NmeaError.MessageToShort;
return(null);
}
string sentenceIdString = sentence.Substring(3, firstComma - 3);
SentenceId sentenceId = new SentenceId(sentenceIdString);
string[] fields = sentence.Substring(firstComma + 1).Split(',');
int lastFieldIdx = fields.Length - 1;
// This returns null as the checksum if there was none, or a very big number if the checksum couldn't be parsed
(int?checksum, string lastField) = GetChecksumAndLastField(fields[lastFieldIdx]);
fields[lastFieldIdx] = lastField;
TalkerSentence result = new TalkerSentence(talkerId, sentenceId, fields);
if (checksum.HasValue)
{
byte realChecksum = CalculateChecksumFromSentenceString(sentence.AsSpan());
if (realChecksum != checksum.Value)
{
errorCode = NmeaError.InvalidChecksum;
return(null);
}
}
errorCode = NmeaError.None;
return(result);
}
/// <summary>
/// Reads NMEA0183 talker sentence from provided string
/// </summary>
/// <param name="sentence">NMEA0183 talker sentence</param>
/// <param name="errorCode">Returns an error code, if the parsing failed</param>
/// <returns>TalkerSentence instance, or null in case of an error</returns>
/// <remarks><paramref name="sentence"/> does not include new line characters</remarks>
public static TalkerSentence?FromSentenceString(string sentence, out NmeaError errorCode)
{
return(FromSentenceString(sentence, TalkerId.Any, out errorCode));
}
/// <summary>
/// Fire an event informing about parser errors
/// </summary>
/// <param name="message">The message to write</param>
/// <param name="error">The kind of error seen</param>
protected void FireOnParserError(string message, NmeaError error)
{
OnParserError?.Invoke(this, message, error);
}
private void ParserOnParserError(NmeaSinkAndSource source, string message, NmeaError errorCode)
{
FireOnParserError(message, errorCode);
}
