在struct和byte数组之间进行转换 [英] Go conversion between struct and byte array

问题描述

我在Go中编写了一个客户端 - 服务器应用程序。我想在Go中执行类似C的类型转换。

I am writing a client - server application in Go. I want to perform C-like type casting in Go.

例如。在Go

type packet struct {
    opcode uint16
    data [1024]byte
}

var pkt1 packet
...
n, raddr, err := conn.ReadFromUDP(pkt1)  // error here

此外，我想要执行C类memcpy（），这将允许我直接映射网络字节流接收到一个结构。

Also I want to perform C-like memcpy(), which will allow me to directly map the network byte stream received to a struct.

例如与上面接收的pkt1

e.g. with above received pkt1

type file_info struct {
    file_size uint32       // 4 bytes
    file_name [1020]byte
}

var file file_info
if (pkt1.opcode == WRITE) {
    memcpy(&file, pkt1.data, 1024)
}

推荐答案

unsafe.Pointer 是，很好，不安全，你实际上不需要它在这里。请改用 encoding / binary 包：

unsafe.Pointer is, well, unsafe, and you don't actually need it here. Use encoding/binary package instead:

// Create a struct and write it.
t := T{A: 0xEEFFEEFF, B: 3.14}
buf := &bytes.Buffer{}
err := binary.Write(buf, binary.BigEndian, t)
if err != nil {
    panic(err)
}
fmt.Println(buf.Bytes())

// Read into an empty struct.
t = T{}
err = binary.Read(buf, binary.BigEndian, &t)
if err != nil {
    panic(err)
}
fmt.Printf("%x %f", t.A, t.B)

a href =http://play.golang.org/p/jcn6ldeAEX>游乐场

Playground

如您所见，它处理大小和字节顺序整齐。

As you can see, it handles sizes and endianness quite neatly.

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