Golang: pe optional header

pe.go

package main

import (
	"debug/pe"
	"fmt"
	"os"
)

func main() {
	file, err := pe.Open(os.Args[1])
	if err != nil {
		fmt.Fprintf(os.Stderr, "pe.Open:%s\n", err)
		os.Exit(1)
	}
	defer file.Close()

	var dataDir [16]pe.DataDirectory

	switch file.OptionalHeader.(type) {
	case *pe.OptionalHeader32:
		fmt.Fprintf(os.Stdout, "Header32\n")
		o := file.OptionalHeader.(*pe.OptionalHeader32)
		dataDir = o.DataDirectory
	case *pe.OptionalHeader64:
		fmt.Fprintf(os.Stdout, "Header64\n")
		o := file.OptionalHeader.(*pe.OptionalHeader64)
		dataDir = o.DataDirectory
	default:
		fmt.Fprintf(os.Stderr, "invalid format\n")
		os.Exit(1)
	}

	fmt.Printf("dataDir:%v\n", dataDir)
}