public unsafe override void Encode(BinaryStreamBase stream, HistorianKey prevKey, HistorianValue prevValue, HistorianKey currentKey, HistorianValue currentValue)
{
if (currentKey.Timestamp == prevKey.Timestamp &&
((currentKey.PointID ^ prevKey.PointID) < 64) &&
currentKey.EntryNumber == 0 &&
currentValue.Value1 <= uint.MaxValue && //must be a 32-bit value
currentValue.Value2 == 0 &&
currentValue.Value3 == 0)
{
if (currentValue.Value1 == 0)
{
stream.Write((byte)((currentKey.PointID ^ prevKey.PointID)));
}
else
{
stream.Write((byte)((currentKey.PointID ^ prevKey.PointID) | 64));
stream.Write((uint)currentValue.Value1);
}
return;
}
byte code = 128;
if (currentKey.Timestamp != prevKey.Timestamp)
{
code |= 64;
}
if (currentKey.EntryNumber != 0)
{
code |= 32;
}
if (currentValue.Value1 > uint.MaxValue)
{
code |= 16;
}
else if (currentValue.Value1 > 0)
{
code |= 8;
}
if (currentValue.Value2 != 0)
{
code |= 4;
}
if (currentValue.Value3 > uint.MaxValue)
{
code |= 2;
}
else if (currentValue.Value3 > 0)
{
code |= 1;
}
stream.Write(code);
if (currentKey.Timestamp != prevKey.Timestamp)
{
stream.Write7Bit(currentKey.Timestamp ^ prevKey.Timestamp);
}
stream.Write7Bit(currentKey.PointID ^ prevKey.PointID);
if (currentKey.EntryNumber != 0)
{
stream.Write7Bit(currentKey.EntryNumber);
}
if (currentValue.Value1 > uint.MaxValue)
{
stream.Write(currentValue.Value1);
}
else if (currentValue.Value1 > 0)
{
stream.Write((uint)currentValue.Value1);
}
if (currentValue.Value2 != 0)
{
stream.Write(currentValue.Value2);
}
if (currentValue.Value3 > uint.MaxValue)
{
stream.Write(currentValue.Value3);
}
else if (currentValue.Value3 > 0)
{
stream.Write((uint)currentValue.Value3);
}
}