| public static CalcCRC ( byte packet, int length ) : short | ||
| packet | byte | |
| length | int | |
| return | short | |
public EventMessage(byte[] msgPacket)
{
short msgCRC;
short expectedCRC;
if (msgPacket == null)
{
throw new ArgumentNullException("msgPacket");
}
byte head = msgPacket[VSCP_POS_HEAD];
_ignoreCRC = ((head & VSCP_NO_CRC_CALC) == VSCP_NO_CRC_CALC);
_ignoreCRC = true;
int incomming_packet_length = msgPacket.Length;
short dataSize = EventHelper.GetDataSize(msgPacket);
int msgLength = msgPacket.Length + VSCP_HEADER_SIZE;
msgLength += (_ignoreCRC) ? 0 : VSCP_SIZE_CRC;
if (msgLength > VSCP_MAX_DATA_SIZE)
{
throw new ApplicationException(string.Format("Invalid event message length: {0}", msgLength));
}
_priority = (EVENT_PRIORITY)(head >> 5);
if (_ignoreCRC == false)
{
msgCRC = EventHelper.GetCRC(msgPacket);
expectedCRC = EventHelper.CalcCRC(msgPacket, msgLength - VSCP_SIZE_CRC);
if (msgCRC != expectedCRC)
{
throw new ApplicationException(string.Format("Invalid event message CRC '{0}' instead of {1}", msgCRC, expectedCRC));
}
}
_event = EventHelper.GetEventCode(msgPacket);
_address = new byte [EventMessage.VSCP_SIZE_ADDRESS];
Buffer.BlockCopy(msgPacket, VSCP_POS_ADDRESS, _address, 0, VSCP_SIZE_ADDRESS);
_data = new Byte [dataSize];
Buffer.BlockCopy(msgPacket, VSCP_POS_DATA, _data, 0, dataSize);
}
public Byte[] GetBytes()
{
short crc;
Byte[] packet;
packet = new Byte[this.Length];
// Head
packet[VSCP_POS_HEAD] = this.HeadByte;
// Event Class and Type
Buffer.BlockCopy(
BitConverter.GetBytes(IPAddress.HostToNetworkOrder(this.EventClass)),
0, packet,
EventMessage.VSCP_POS_CLASS,
EventMessage.VSCP_SIZE_CLASS);
Buffer.BlockCopy(
BitConverter.GetBytes(IPAddress.HostToNetworkOrder(this.EventType)),
0, packet,
EventMessage.VSCP_POS_TYPE,
EventMessage.VSCP_SIZE_TYPE);
// Address
Buffer.BlockCopy(this.AddressBytes, 0, packet, VSCP_POS_ADDRESS, VSCP_SIZE_ADDRESS);
// Data Size
Buffer.BlockCopy(this.DataSizeBytes, 0, packet, VSCP_POS_DATA_SIZE, VSCP_SIZE_DATA_SIZE);
// Data - limited to 512-25=487 bytes
Buffer.BlockCopy(this.DataBytes, 0, packet, VSCP_POS_DATA, this.DataSize);
if (!_ignoreCRC)
{
crc = EventHelper.CalcCRC(packet, packet.Length - VSCP_SIZE_CRC);
Buffer.BlockCopy(
BitConverter.GetBytes(IPAddress.HostToNetworkOrder(crc)),
0, packet, packet.Length - VSCP_SIZE_CRC, VSCP_SIZE_CRC);
}
return(packet);
}
