Data commit

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

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"text/tabwriter"
+)
+
+// parseIPPort parses an IP with an optional port, returning an IP and a port (or nil
+// if no port was present in the given address).
+func parseIPPort(address string) (net.IP, *uint64, error) {
+	ip := net.ParseIP(address)
+	if ip != nil {
+		return ip, nil, nil
+	}
+
+	host, portStr, err := net.SplitHostPort(address)
+	if err != nil {
+		return nil, nil, fmt.Errorf("splithostport failed: %w", err)
+	}
+
+	port, err := strconv.ParseUint(portStr, 10, 16)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to parse port: %w", err)
+	}
+
+	ip = net.ParseIP(host)
+	if ip == nil {
+		return nil, nil, fmt.Errorf("failed to parse ip address")
+	}
+
+	return ip, &port, nil
+}
+
+func ipVersion(ip net.IP) int {
+	if ip.To4() == nil {
+		return 6
+	}
+
+	return 4
+}
+
+func main() {
+	testCases := []string{
+		"127.0.0.1",
+		"127.0.0.1:80",
+		"::1",
+		"[::1]:443",
+		"2605:2700:0:3::4713:93e3",
+		"[2605:2700:0:3::4713:93e3]:80",
+	}
+
+	w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
+
+	writeTSV := func(w io.Writer, args ...interface{}) {
+		fmt.Fprintf(w, strings.Repeat("%s\t", len(args)), args...)
+		fmt.Fprintf(w, "\n")
+	}
+
+	writeTSV(w, "Input", "Address", "Space", "Port")
+
+	for _, addr := range testCases {
+		ip, port, err := parseIPPort(addr)
+		if err != nil {
+			panic(err)
+		}
+
+		portStr := "n/a"
+		if port != nil {
+			portStr = fmt.Sprint(*port)
+		}
+
+		ipVersion := fmt.Sprintf("IPv%d", ipVersion(ip))
+
+		writeTSV(w, addr, hex.EncodeToString(ip), ipVersion, portStr)
+	}
+
+	w.Flush()
+}