package wal

import "encoding/binary"

type walHeader struct {
	FirstSegmentID int64
	LastSegmentID  int64
}

func (h walHeader) WriteTo(b []byte) {
	vals := []int64{h.FirstSegmentID, h.LastSegmentID}

	for _, val := range vals {
		binary.LittleEndian.PutUint64(b[0:8], uint64(val))
		b = b[8:]
	}
}

func (h *walHeader) ReadFrom(b []byte) {
	ptrs := []*int64{&h.FirstSegmentID, &h.LastSegmentID}
	for _, ptr := range ptrs {
		*ptr = int64(binary.LittleEndian.Uint64(b[0:8]))
		b = b[8:]
	}
}