msg.go

package main

import (
	"bytes"
	"encoding/binary"
)

const magicLen = 17
const magicHead = "blockSync-ver0.01"

type Msg struct {
	MagicHead  [magicLen]byte
	BlockIdx   uint32
	BlockSize  uint32
	FileSize   uint64
	DataSize   uint32
	Compressed bool
	Zero       bool
	Done       bool
}

func stringToFixedSizeArray(s string) [magicLen]byte {
	var arr [magicLen]byte
	copy(arr[:], s)
	return arr
}

func pack(data *Msg) ([]byte, error) {
	buf := new(bytes.Buffer)
	if err := binary.Write(buf, binary.LittleEndian, data); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

func unpack(dataBytes []byte) (*Msg, error) {
	data := &Msg{}
	buf := bytes.NewReader(dataBytes)
	if err := binary.Read(buf, binary.LittleEndian, data); err != nil {
		return nil, err
	}
	return data, nil
}