I want to edit struct fields' value as interface{} parameters. I done almost, but when struct has array field, I couldn't modify that. I tried to find proper function with array value, but I couldn't find that. Here is my code.
edit_struct_via _interface.go
package main
import (
"reflect"
"fmt"
)
type myStruct struct {
Name [8]byte
TID [4]byte
Chksum uint16
}
func main() {
var s = new(myStruct)
name := []byte("Mike")
tid := []byte{0x01, 0x02, 0x03, 0x05}
setArrayField(name, s.Name[:])
setArrayField(tid, s.TID[:])
s.Chksum = 0x0101
myObj := reflect.ValueOf(s).Elem()
typeOfMyObj := myObj.Type()
for i := 0; i < myObj.NumField(); i++ {
f := myObj.Field(i)
fmt.Printf("%d: %s %s = %v\n", i,
typeOfMyObj.Field(i).Name, f.Type(), f.Interface())
}
newName := []byte("Emil")
myObj.Field(0).SetBytes(newName[:])
// I trying to change array field at here, but panic occur here.
// Because SetBytes must been called on slice, but myObj.Field(0) is array.
myObj.Field(2).SetUint(99) // It works.
fmt.Println("s is now: ", *s)
}
func setArrayField(src []byte, target []byte) {
// retun if src is bigger than target
if len(src) > len(target){
return
}
for index, item := range src {
target[index] = item
}
}
When I run above code, I get
0: Name [8]uint8 = [77 105 107 101 0 0 0 0]
1: TID [4]uint8 = [1 2 3 5]
2: Chksum uint16 = 257
panic: reflect: call of reflect.Value.SetBytes on array Value
goroutine 1 [running]:
reflect.flag.mustBe(...)
/usr/local/go/src/reflect/value.go:208
reflect.Value.SetBytes(0x4a6180, 0xc000098010, 0x191, 0xc000098078, 0x4, 0x4)
/usr/local/go/src/reflect/value.go:1557 +0x140
main.main()
/home/hornet/go/src/gateway-golang/edit_struct_via _interface.go:33 +0x522
exit status 2
I'm using Ubuntu 18.04 and go1.13 linux/amd64
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