utils.go

package main

import (
	"fmt"
	"net"
	"os"
)

func show(host string, ip net.IP, mode bool) {
	if mode {
		fmt.Println(host)
	} else {
		fmt.Println(ip)
	}
}

func inc(ip net.IP) {
	for j := len(ip) - 1; j >= 0; j-- {
		ip[j]++
		if ip[j] > 0 {
			break
		}
	}
}

func hosts(cidr string) ([]string, error) {
	ip, ipnet, err := net.ParseCIDR(cidr)
	if err != nil {
		return nil, err
	}

	var ips []string
	for ip := ip.Mask(ipnet.Mask); ipnet.Contains(ip); inc(ip) {
		ips = append(ips, ip.String())
	}

	lenIPs := len(ips)
	switch {
	case lenIPs < 2:
		return ips, nil
	default:
		return ips[1 : len(ips)-1], nil
	}
}

func isStdin() bool {
	f, e := os.Stdin.Stat()
	if e != nil {
		return false
	}

	if f.Mode()&os.ModeNamedPipe == 0 {
		return false
	}

	return true
}