golang struct 和 []byte 互转
example1
type MyStruct struct {
A int
B int
}
var sizeOfMyStruct = int(unsafe.Sizeof(MyStruct{}))
func MyStructToBytes(s *MyStruct) []byte {
var x reflect.SliceHeader
x.Len = sizeOfMyStruct
x.Cap = sizeOfMyStruct
x.Data = uintptr(unsafe.Pointer(s))
return *(*[]byte)(unsafe.Pointer(&x))
}
func BytesToMyStruct(b []byte) *MyStruct {
return (*MyStruct)(unsafe.Pointer(
(*reflect.SliceHeader)(unsafe.Pointer(&b)).Data,
))
}
example2
import (
"fmt"
"unsafe"
)
type TestStructTobytes struct {
data int64
}
type SliceMock struct {
addr uintptr
len int
cap int
}
func main() {
var testStruct = &TestStructTobytes{100}
Len := unsafe.Sizeof(*testStruct)
testBytes := &SliceMock{
addr: uintptr(unsafe.Pointer(testStruct)),
cap: int(Len),
len: int(Len),
}
data := *(*[]byte)(unsafe.Pointer(testBytes))
fmt.Println("[]byte is : ", data)
var ptestStruct *TestStructTobytes = *(**TestStructTobytes)(unsafe.Pointer(&data))
fmt.Println("ptestStruct.data is : ", ptestStruct.data)
}
// 由于在golang中编译器不将[]byte视为指针,所以要使用其地址进行转换,由于[]byte底层存放的是指向数据的地址。用[]byte的地址就需要使用双层指针转换,然后再指向其内容,得出来的就是转换对应struct的指针了。
高效的字符串和字节数组转换
func bytes2str(b []byte) string {
return *(*string)(unsafe.Pointer(&b))
}
func str2bytes(s string) []byte {
x := (*[2]uintptr)(unsafe.Pointer(&s)) // 获取s的起始地址开始后的两个 uintptr 指针
h := [3]uintptr{x[0], x[1], x[1]} // 构造三个指针数组
return *(*[]byte)(unsafe.Pointer(&h))
}
作者:百里求一
出处:http://www.cnblogs.com/bergus/
我的语雀: https://www.yuque.com/barry.bai
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