text: #include <arpa/inet.h>
  #include <QHostInfo>
  
  // hyperion local includes
  #include "LedDeviceUdpE131.h"
  
  LedDeviceUdpE131::LedDeviceUdpE131(const QJsonObject &deviceConfig)
  	: ProviderUdp()
  {
  	_deviceReady = init(deviceConfig);
  }
  
  bool LedDeviceUdpE131::init(const QJsonObject &deviceConfig)
  {
  	_LatchTime_ns = 104000;
  	_port = 5568;
  	ProviderUdp::init(deviceConfig);
  	_e131_universe = deviceConfig["universe"].toInt(1);
  	_e131_source_name = deviceConfig["source-name"].toString("hyperion on "+QHostInfo::localHostName()).toStdString();
  	QString _json_cid = deviceConfig["cid"].toString("");
  
  	if (_json_cid.isEmpty()) 
  	{
  		_e131_cid = QUuid::createUuid();
  		Debug( _log, "e131 no cid found, generated %s", _e131_cid.toString().toStdString().c_str());
  	} else {
  		_e131_cid = QUuid(_json_cid);
  		Debug( _log, "e131  cid found, using %s", _e131_cid.toString().toStdString().c_str());
  	}
  
  	return true;
  }
  
  LedDevice* LedDeviceUdpE131::construct(const QJsonObject &deviceConfig)
  {
  	return new LedDeviceUdpE131(deviceConfig);
  }
  
  
  // populates the headers
  void LedDeviceUdpE131::prepare(const unsigned this_universe, const unsigned this_dmxChannelCount)
  {
  	memset(e131_packet.raw, 0, sizeof(e131_packet.raw));
  
  	/* Root Layer */
  	e131_packet.preamble_size = htons(16);
  	e131_packet.postamble_size = 0;
  	memcpy (e131_packet.acn_id, _acn_id, 12);
  	e131_packet.root_flength = htons(0x7000 | (110+this_dmxChannelCount) );
  	e131_packet.root_vector = htonl(VECTOR_ROOT_E131_DATA);
  	memcpy (e131_packet.cid, _e131_cid.toRfc4122().constData() , sizeof(e131_packet.cid) );
  
  	/* Frame Layer */
  	e131_packet.frame_flength = htons(0x7000 | (88+this_dmxChannelCount));
  	e131_packet.frame_vector = htonl(VECTOR_E131_DATA_PACKET);
  	snprintf (e131_packet.source_name, sizeof(e131_packet.source_name), "%s", _e131_source_name.c_str() );
  	e131_packet.priority = 100;
  	e131_packet.reserved = htons(0);
  	e131_packet.options = 0;	// Bit 7 =  Preview_Data
  					// Bit 6 =  Stream_Terminated
  					// Bit 5 = Force_Synchronization
  	e131_packet.universe = htons(this_universe);
  
  	/* DMX Layer */
  	e131_packet.dmp_flength = htons(0x7000 | (11+this_dmxChannelCount));
  	e131_packet.dmp_vector = VECTOR_DMP_SET_PROPERTY;
  	e131_packet.type = 0xa1;
  	e131_packet.first_address = htons(0);
  	e131_packet.address_increment = htons(1);
  	e131_packet.property_value_count = htons(1+this_dmxChannelCount);
  
  	e131_packet.property_values[0] = 0;	// start code
  }
  
  int LedDeviceUdpE131::write(const std::vector<ColorRgb> &ledValues)
  {
  	int retVal            = 0;
  	int thisChannelCount = 0;
  	int dmxChannelCount  = _ledRGBCount;
  	const uint8_t * rawdata = reinterpret_cast<const uint8_t *>(ledValues.data());
  
  	_e131_seq++;
  
  	for (int rawIdx = 0; rawIdx < dmxChannelCount; rawIdx++)
  	{
  		if (rawIdx % DMX_MAX == 0) // start of new packet
  		{
  			thisChannelCount = (dmxChannelCount - rawIdx < DMX_MAX) ? dmxChannelCount % DMX_MAX : DMX_MAX;
  //			                       is this the last packet?         ?       ^^ last packet      : ^^ earlier packets
  
  			prepare(_e131_universe + rawIdx / DMX_MAX, thisChannelCount);
  			e131_packet.sequence_number = _e131_seq;
  		}
  
  		e131_packet.property_values[1 + rawIdx%DMX_MAX] = rawdata[rawIdx];
  
  //     is this the      last byte of last packet    ||   last byte of other packets
  		if ( (rawIdx == dmxChannelCount-1) || (rawIdx %DMX_MAX == DMX_MAX-1) )
  		{
  #undef e131debug
  #if e131debug
  			Debug (_log, "send packet: rawidx %d dmxchannelcount %d universe: %d, packetsz %d"
  				, rawIdx
  				, dmxChannelCount
  				, _e131_universe + rawIdx / DMX_MAX
  				, E131_DMP_DATA + 1 + thisChannelCount
  				);
  #endif
  			retVal &= writeBytes(E131_DMP_DATA + 1 + thisChannelCount, e131_packet.raw);
  		}
  	}
  
  	return retVal;
  }
  
  