package node

import "unsafe"

// ----------------------------------------------------------------------------

const (
	headerSize = 12

	controlStreamID       = 2
	controlHeaderSize     = 24
	controlCipherOverhead = 16

	dataStreamID       = 1
	dataHeaderSize     = 12
	dataCipherOverhead = 16

	forwardStreamID = 3
)

type xHeader struct {
	StreamID byte
	Counter  uint64 // Init with fasttime.Now() << 30 to ensure monotonic.
	SourceIP byte
	DestIP   byte
}

func (h *xHeader) Parse(b []byte) {
	h.StreamID = b[0]
	h.Counter = *(*uint64)(unsafe.Pointer(&b[1]))
	h.SourceIP = b[9]
	h.DestIP = b[10]
}

func (h *xHeader) Marshal(buf []byte) {
	buf[0] = h.StreamID
	*(*uint64)(unsafe.Pointer(&buf[1])) = h.Counter
	buf[9] = h.SourceIP
	buf[10] = h.DestIP
	buf[11] = 0
}