byte[] IArchive.ReadMetaData(int historianID)
{
MetadataRecord record = ReadMetadataRecord(historianID);
if ((object)record != null)
{
return(record.BinaryImage());
}
return(null);
}
/// <summary>
/// Processes <see cref="PacketType4"/>.
/// </summary>
/// <returns>An <see cref="IEnumerable{T}"/> object containing the binary images of <see cref="MetadataRecord.Summary"/> for the <see cref="QueryPacketBase.RequestIDs"/>.</returns>
protected virtual IEnumerable <byte[]> Process()
{
if (Archive == null)
{
yield break;
}
byte[] data;
MetadataRecord record;
if (RequestIDs.Count == 0 || (RequestIDs.Count == 1 && RequestIDs[0] == -1))
{
// Information for all defined records is requested.
int id = 0;
while (true)
{
data = Archive.ReadMetaData(++id);
if (data == null)
{
// No more records.
break;
}
record = new MetadataRecord(id, MetadataFileLegacyMode.Enabled, data, 0, data.Length);
// Only send information that has changed.
if (record.GeneralFlags.Changed)
{
// Reset the "changed" field.
record.GeneralFlags.Changed = false;
Archive.WriteMetaData(id, record.BinaryImage());
yield return(record.Summary.BinaryImage());
}
}
}
else
{
// Information for specific records is requested.
foreach (int id in RequestIDs)
{
data = Archive.ReadMetaData(id);
if (data == null)
{
// ID is invalid.
continue;
}
record = new MetadataRecord(id, MetadataFileLegacyMode.Enabled, data, 0, data.Length);
// Only send information that has changed.
if (record.GeneralFlags.Changed)
{
// Reset the "changed" field.
record.GeneralFlags.Changed = false;
Archive.WriteMetaData(id, record.BinaryImage());
yield return(record.Summary.BinaryImage());
}
}
}
yield return(new MetadataRecord(-1, MetadataFileLegacyMode.Enabled).Summary.BinaryImage()); // To indicate EOT.
}