gencode example

gencode.go

package main

import (
	"fmt"
	"io"
	"time"
	"unsafe"
)

var (
	_ = unsafe.Sizeof(0)
	_ = io.ReadFull
	_ = time.Now()
)

type Pubsub struct {
	isSubscribe bool
	topic       string
	payload     []byte
}

func (d *Pubsub) Size() (s uint64) {

	{
		l := uint64(len(d.topic))

		{

			t := l
			for t >= 0x80 {
				t >>= 7
				s++
			}
			s++

		}
		s += l
	}
	{
		l := uint64(len(d.payload))

		{

			t := l
			for t >= 0x80 {
				t >>= 7
				s++
			}
			s++

		}
		s += l
	}
	s += 1
	return
}
func (d *Pubsub) Marshal(buf []byte) ([]byte, error) {
	size := d.Size()
	{
		if uint64(cap(buf)) >= size {
			buf = buf[:size]
		} else {
			buf = make([]byte, size)
		}
	}
	i := uint64(0)

	{
		if d.isSubscribe {
			buf[0] = 1
		} else {
			buf[0] = 0
		}
	}
	{
		l := uint64(len(d.topic))

		{

			t := uint64(l)

			for t >= 0x80 {
				buf[i+1] = byte(t) | 0x80
				t >>= 7
				i++
			}
			buf[i+1] = byte(t)
			i++

		}
		copy(buf[i+1:], d.topic)
		i += l
	}
	{
		l := uint64(len(d.payload))

		{

			t := uint64(l)

			for t >= 0x80 {
				buf[i+1] = byte(t) | 0x80
				t >>= 7
				i++
			}
			buf[i+1] = byte(t)
			i++

		}
		copy(buf[i+1:], d.payload)
		i += l
	}
	return buf[:i+1], nil
}

func (d *Pubsub) Unmarshal(buf []byte) (uint64, error) {
	i := uint64(0)

	{
		d.isSubscribe = buf[i+0] == 1
	}
	{
		l := uint64(0)

		{

			bs := uint8(7)
			t := uint64(buf[i+1] & 0x7F)
			for buf[i+1]&0x80 == 0x80 {
				i++
				t |= uint64(buf[i+1]&0x7F) << bs
				bs += 7
			}
			i++

			l = t

		}
		d.topic = string(buf[i+1 : i+1+l])
		i += l
	}
	{
		l := uint64(0)

		{

			bs := uint8(7)
			t := uint64(buf[i+1] & 0x7F)
			for buf[i+1]&0x80 == 0x80 {
				i++
				t |= uint64(buf[i+1]&0x7F) << bs
				bs += 7
			}
			i++

			l = t

		}
		if uint64(cap(d.payload)) >= l {
			d.payload = d.payload[:l]
		} else {
			d.payload = make([]byte, l)
		}
		copy(d.payload, buf[i+1:])
		i += l
	}
	return i + 1, nil
}

func main() {
	pub:=Pubsub{isSubscribe:true, topic: "carLong/Lat", payload:[]byte("stringingingdingdong")}
	buf, _ := pub.Marshal(nil)
	fmt.Println(pub.Size(), buf)
	newPub :=Pubsub{}
	newPub.Unmarshal(buf)
	fmt.Println(newPub)
}