meta.go

package main

import "encoding/binary"

//meta will be stored at 0 pageNum and will have info about where freelist is stored
const (
	metaPageNum = 0
)

type meta struct {
	//to store root of B-Tree
	root         pgnum
	freelistPage pgnum
}

func newEmptyMeta() *meta {
	return &meta{}
}

//POS is just a cursor we move in order to read from disk.
func (m *meta) serialize(buf []byte) {
	pos := 0

	binary.LittleEndian.PutUint64(buf[pos:], uint64(m.root))
	pos += pageNumSize

	binary.LittleEndian.PutUint64(buf[pos:], uint64(m.freelistPage))
	pos += pageNumSize
}

func (m *meta) deserialize(buf []byte) {
	pos := 0

	m.root = pgnum(binary.LittleEndian.Uint64(buf[pos:]))
	pos += pageNumSize

	m.freelistPage = pgnum(binary.LittleEndian.Uint64(buf[pos:]))
	pos += pageNumSize
}