forked from foxcpp/wirebox
/
pack.go
81 lines (65 loc) · 1.4 KB
/
pack.go
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package wboxproto
import (
"errors"
"fmt"
"google.golang.org/protobuf/proto"
)
//go:generate protoc --go_out=. protocol.proto
type Message = proto.Message
type MsgType byte
const (
MsgSolict MsgType = 1
MsgCfg MsgType = 2
MsgNack MsgType = 3
Version byte = 1
)
var (
ErrUnknownVersion = errors.New("proto: unknown protocol version")
)
func Unpack(b []byte) (proto.Message, error) {
if len(b) < 2 {
return nil, errors.New("proto: malformed datagram")
}
version := b[0]
msgType := MsgType(b[1])
if version != Version {
return nil, ErrUnknownVersion
}
var msg proto.Message
switch msgType {
case MsgSolict:
msg = &CfgSolict{}
case MsgCfg:
msg = &Cfg{}
case MsgNack:
msg = &Nack{}
default:
return nil, errors.New("proto: unknown message type")
}
if err := proto.Unmarshal(b[2:], msg); err != nil {
return nil, fmt.Errorf("proto: unpack: %w", err)
}
return msg, nil
}
func Pack(msg proto.Message) ([]byte, error) {
var msgType MsgType
switch msg.(type) {
case *CfgSolict:
msgType = MsgSolict
case *Cfg:
msgType = MsgCfg
case *Nack:
msgType = MsgNack
default:
return nil, errors.New("proto: unknown message type")
}
body, err := proto.Marshal(msg)
if err != nil {
return nil, fmt.Errorf("proto: pack: %w", err)
}
payload := make([]byte, 2, len(body)+2)
payload[0] = Version
payload[1] = byte(msgType)
payload = append(payload, body...)
return payload, nil
}