UintToIpAndToUint.go

package main

import "net"
import "fmt"
import "strconv"
import "strings"

func main() {
	b, _ := IPToUint("111.11.191.17")
	fmt.Println("111.11.191.17")
	fmt.Println(b)
	fmt.Println(UintToIP(b))
}

func IPToUint(ipstr string) (uint64, error) {
	ip := net.ParseIP(ipstr)
	ip4 := ip.To4()
	if ip4 == nil {
		return 0, fmt.Errorf("illegal: %v", ip)
	}

	bin := make([]string, len(ip4))
	for i, v := range ip4 {
		bin[i] = fmt.Sprintf("%08b", v)
	}
	return strconv.ParseUint(strings.Join(bin, ""), 2, 64)
}

func UintToIP(ip_uint uint64) (string, error) {
	result := make(net.IP, 4)
	for i := 0; i < 4; i++ {
		result[3-i] = byte((ip_uint >> uint(8*i)) & 0xff)
	}
	return result.String(), nil
}