private void SortAndBuildInternalStructures()
{
if (PGNDefns != null)
{
Array.Sort(pgnDefns);
// Identify any duplicate PGNs in the data
for (int i = 0; i < pgnDefns.Length; i++)
{
pgnDefns[i].HasMultipleDefinitions = false;
}
for (int i = 0; i < pgnDefns.Length - 1; i++)
{
if (pgnDefns[i].PGN == pgnDefns[i + 1].PGN)
{
pgnDefns[i].HasMultipleDefinitions = true;
pgnDefns[i + 1].HasMultipleDefinitions = true;
}
}
// Now (re)build up a dictionary of the PGN indices, recording the *first* instance of each PGN
PGNDictionary.Clear();
for (int i = pgnDefns.Length - 1; i >= 0; i--)
{
PGNDictionary[pgnDefns[i].PGN] = i;
}
// Finally we sort all the fields
foreach (PGNDefn p in PGNDefns)
{
p.SortFields();
}
// ReBuildPGNDictionary();
}
}
// Given a (possibly partially) completed PGN message,
// described by a PGN number, and the apparent 'byte length'
// for the message (which is only relevant if the message is a
// multiple packet message), return the
// PGNDefn that allows this message to be decoded
public PGNDefn GetPGNDefn(N2kFrame msg)
{
uint PGN = (uint)msg.Header.PGN;
int pgnIndex;
if (!PGNDictionary.TryGetValue(PGN, out pgnIndex))
{
// No matching PGN definition; return UnknownPGNDefn
return(UnknownPGNDefn);
}
else
{
PGNDefn pgn = PGNDefns[pgnIndex];
// Is this a multiple definition PGN? (If so, it must be a fast packet PGN?)
if (!pgn.HasMultipleDefinitions)
{
// Only one matching definition available; return it
// int iBytesTransmitted = pgn.ByteLength <= 8 ? msg.Data.Length : msg.Data[1];
return(PGNDefns[pgnIndex]);
}
else
{
// Find the matching definition
while ((pgnIndex < PGNDefns.Length) && (PGNDefns[pgnIndex].PGN == pgn.PGN))
{
if (PGNDefns[pgnIndex].ByteLength == msg.Data[1])
{
return(PGNDefns[pgnIndex]);
}
else
{
// Find any PGN that is not too long, just on case we cannot find any with an exact match
if (pgn.ByteLength < msg.Data[1])
{
pgn = PGNDefns[pgnIndex];
}
pgnIndex++;
}
}
return(pgn);
}
}
}
