Function NewPacket

packet.go:654–684

NewPacket creates a new Packet object from a set of bytes. The firstLayerDecoder tells it how to interpret the first layer from the bytes, future layers will be generated from that first layer automatically.

(data []byte, firstLayerDecoder Decoder, options DecodeOptions)

// firstLayerDecoder tells it how to interpret the first layer from the bytes,
// future layers will be generated from that first layer automatically.
func NewPacket(data []byte, firstLayerDecoder Decoder, options DecodeOptions) Packet {
	if !options.NoCopy {
		dataCopy := make([]byte, len(data))
		copy(dataCopy, data)
		data = dataCopy
	}
	if options.Lazy {
		p := &lazyPacket{
			packet: packet{data: data, decodeOptions: options},
			next:   firstLayerDecoder,
		}
		p.layers = p.initialLayers[:0]
		// Crazy craziness:
		// If the following return statemet is REMOVED, and Lazy is FALSE, then
		// eager packet processing becomes 17% FASTER.  No, there is no logical
		// explanation for this.  However, it's such a hacky micro-optimization that
		// we really can't rely on it.  It appears to have to do with the size the
		// compiler guesses for this function's stack space, since one symptom is
		// that with the return statement in place, we more than double calls to
		// runtime.morestack/runtime.lessstack.  We'll hope the compiler gets better
		// over time and we get this optimization for free.  Until then, we'll have
		// to live with slower packet processing.
		return p
	}
	p := &eagerPacket{
		packet: packet{data: data, decodeOptions: options},
	}
	p.layers = p.initialLayers[:0]
	p.initialDecode(firstLayerDecoder)
	return p
}

// PacketDataSource is an interface for some source of packet data.  Users may
// create their own implementations, or use the existing implementations in