go_cstruct

go-bit

一个对 golang 结构进行编码/解码的库，支持切片数据，并支持校验。 Go struct 与 C struct 对应，内存分布一致。

Installation

go get -u github.com/piaoxue1949/go-cstruct

Usage

这是一个解码TCP标头的简单示例。（大端）

1. 将以下代码保存为tcp.go。
2. go mod init go-cstruct-example
3. go mod tidy
4. go run tcp.go

package main

import (
	"bytes"
	"encoding/binary"
	"fmt"
	go_cstruct "github.com/piaoxue1949/go-cstruct"
)

func main() {
	type TcpHeader struct {
		SrcPort    uint16
		DstPort    uint16
		SeqNo      uint32
		AckNo      uint32
		HeaderLen  [4]bool
		Reserved   [3]bool `cst:"skip"`
		NS         bool
		CWR        bool
		ECE        bool
		URG        bool
		ACK        bool
		PSH        bool
		RST        bool
		SYN        bool
		FIN        bool
		WinSize    uint16
		CheckSum   uint16
		EmePointer uint16
	}

	s := TcpHeader{}

	buf := []byte{0xd8, 0x65, 0x01, 0xbb, 0x4b, 0xe0, 0x76, 0xcd, 0x48, 0xc8, 0x70, 0x8f, 0x50, 0x10, 0x10,
		0x18, 0x0e, 0xc1, 0x00, 0x00}

	if err := go_cstruct.Decode(buf, binary.BigEndian, &s); err != nil {
		fmt.Printf("error:%s", err)
	}

	fmt.Printf("src=%d dst=%d\n", s.SrcPort, s.DstPort)
	fmt.Printf("SeqNo=%d AckNo=%d\n", s.SeqNo, s.AckNo)
	fmt.Printf("HeaderLen=%d\n", go_cstruct.BoolsToNumber(s.HeaderLen[:]))
	fmt.Printf("Ack=%t\n", s.ACK)
}

此外，还有一个自动编码和解码切片的例子

type SmsType uint8

const (
	SmsTypeLogin        SmsType = 1 // 登录
	SmsTypeUpdateMobile SmsType = 2 // 修改手机号
)

type SendSmsReq struct {
	SmsType SmsType `v:"enums"`
	Mobile  []byte  `cst:"len-size:1"`
	Code    []byte  `cst:"len-size:1"`
}

//上面的代码位于test_types/types.go
// 枚举的自动验证需要使用goframe库

func TestCheckAndWrite(t *testing.T) {
	ctx := context.TODO()
	req := &test_types.SendSmsReq{
		SmsType: test_types.SmsTypeLogin,
		Mobile:  []byte("13800138000"),
		Code:    []byte{0x01, 0x02},
	}
	data, err := go_cstruct.CheckAndEncode(ctx, binary.BigEndian, req)
	if err != nil {
		t.Errorf("CheckAndWrite() error = %v", err)
		return
	}
	expect := []byte{0x01, 11, '1', '3', '8', '0', '0', '1', '3', '8', '0', '0', '0', 2, 0x1, 0x2}
	if !bytes.Equal(data, expect) {
		t.Errorf("CheckAndWrite() = %v, want %v", data, expect)
	}
	req.SmsType = 3
	_, err = go_cstruct.CheckAndEncode(ctx, binary.BigEndian, req)
	if err == nil {
		t.Errorf("Check invalid SmsType %v failed", req.SmsType)
		return
	}
}

func TestDecodeAndCheck(t *testing.T) {
	ctx := context.TODO()
	req := &test_types.SendSmsReq{}
	buf := []byte{0x01, 11, '1', '3', '8', '0', '0', '1', '3', '8', '0', '0', '0', 2, 0x1, 0x2}
	err := go_cstruct.DecodeAndCheck(ctx, buf, binary.BigEndian, req)
	if err != nil {
		t.Errorf("ReadAndCheck() error = %v", err)
		return
	}
	expect := &test_types.SendSmsReq{
		SmsType: test_types.SmsTypeLogin,
		Mobile:  []byte("13800138000"),
		Code:    []byte{0x1, 0x2},
	}
	if !reflect.DeepEqual(req, expect) {
		t.Errorf("ReadAndCheck() = %v, want %v", req, expect)
	}
	buf[0] = 3
	err = go_cstruct.DecodeAndCheck(ctx, buf, binary.BigEndian, req)
	if err == nil {
		t.Errorf("Check invalid SmsType %v failed", req.SmsType)
		return
	}
}

结构体标签

该包支持结构标签。

文档

https://pkg.go.dev/github.com/piaoxue1949/go-cstruct

License

Apache License v2.0

参考项目

https://github.com/fananchong/cstruct-go

https://github.com/nokute78/go-bit