Update all new Tasks

Task/Parse-an-IP-Address/Go/parse-an-ip-address.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+)
+
+func ParseIPPort(s string) (ip net.IP, port, space string, err error) {
+	ip = net.ParseIP(s)
+	if ip == nil {
+		var host string
+		host, port, err = net.SplitHostPort(s)
+		if err != nil {
+			return
+		}
+		if port != "" {
+			// This check only makes sense if service names are not allowed
+			if _, err = strconv.ParseUint(port, 10, 16); err != nil {
+				return
+			}
+		}
+		ip = net.ParseIP(host)
+	}
+	if ip == nil {
+		err = errors.New("invalid address format")
+	} else {
+		space = "IPv6"
+		if ip4 := ip.To4(); ip4 != nil {
+			space = "IPv4"
+			ip = ip4
+		}
+	}
+	return
+}
+
+func main() {
+	var testCases = []string{
+		"127.0.0.1",
+		"127.0.0.1:80",
+		"::1",
+		"[::1]:80",
+		"2605:2700:0:3::4713:93e3",
+		"[2605:2700:0:3::4713:93e3]:80",
+	}
+	max := len("Input")
+	for _, addr := range testCases {
+		if len(addr) > max {
+			max = len(addr)
+		}
+	}
+	fmt.Printf("%-*s  %*s  %-6s %s\n", max, "Input",
+		2*net.IPv6len, "Address", "Space", "Port")
+	for _, addr := range testCases {
+		fmt.Printf("%-*s  ", max, addr)
+		ip, port, space, err := ParseIPPort(addr)
+		if err != nil {
+			fmt.Println(err)
+			continue
+		}
+		fmt.Print(strings.Repeat("  ", net.IPv6len-len(ip)))
+		for _, b := range ip {
+			fmt.Printf("%02x", b)
+		}
+		fmt.Printf("  %-6s %s\n", space, port)
+	}
+}