/// <summary>
/// Writes the Frame portion of the message header to the buffer.
/// See http://lan.developer.lifx.com/docs/header-description for more details.
/// </summary>
/// <param name="buffer">The buffer to write to.</param>
private void WriteFrame(MemoryStream buffer)
{
Debug.Assert(buffer != null);
// Write the message size (2B)
//
buffer.LitteEndianWriteUInt16(MessageSizeInBytes);
// The next 2 bytes contain:
// - The Origin field (2 bits, always set to 0)
// - The Tagged flag (1 bit - 1 if Target is specific device, 0 if all devices)
// - The Addressable flag (1 bit, always set to 1)
// - The protocol number (12 bits, always set to 1024)
//
const UInt16 TaggedFlag = 0x2000;
const UInt16 AddressableFlag = 0x1000;
UInt16 flagsAndProtocol = AddressableFlag | Constants.LifXProtocolNumber;
if (Target == MacAddress.Empty)
{
flagsAndProtocol |= TaggedFlag;
}
buffer.LitteEndianWriteUInt16(flagsAndProtocol);
// The last 4 bytes are the message Source.
//
buffer.LitteEndianWriteUInt32(Source);
}
/// <summary>
/// Writes the Protocol Header portion of the message header to the buffer.
/// See http://lan.developer.lifx.com/docs/header-description for more details.
/// </summary>
/// <param name="buffer">The buffer to write to.</param>
private void WriteProtocolHeader(MemoryStream buffer)
{
Debug.Assert(buffer != null);
// The first 8 bytes are unusued and marked "Reserved".
//
buffer.WriteZeros(8);
// The next 2 bytes are the MessageType.
//
buffer.LitteEndianWriteUInt16((UInt16)MessageType);
// The last 2 bytes are also unusued and marked "Reserved".
//
buffer.WriteZeros(2);
}
