Added command line argument to extract payload

cmd/sdb/main.go

@@ -5,69 +5,94 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"flag"
 )
 
 func main() {
-	if len(os.Args) < 2 {
-		fmt.Fprintf(os.Stderr,
-			"required argument missing\n")
-		os.Exit(1)
+	flags := flag.NewFlagSet("sdb", flag.ExitOnError)
+	flags.SetOutput(os.Stdout)
+	flags.Usage = func() {
+		fmt.Fprintf(flags.Output(),
+			"Usage: %s [OPTION] <files> ...\nOptions:\n",
+			os.Args[0])
+		flags.PrintDefaults()
 	}
 
-	raw, err := ioutil.ReadFile(os.Args[1])
-	if err != nil {
-		fmt.Fprintf(os.Stderr,
-			"error reading \"%s\": %s\n",
-			os.Args[1], err.Error())
-	}
+	plonly := flags.Bool("payload", false, "only return the payload")
+
+	flags.Parse(os.Args[1:])
 
-	data, err := sdb.ParseSDB(raw)
-	if err != nil {
-		fmt.Fprintf(os.Stderr,
-			"%s\n", err.Error())
+	if flags.NArg() < 1 {
+		fmt.Fprintf(os.Stderr, "files parameter cannot be empty\n")
 		os.Exit(1)
 	}
 
-	fmt.Printf("Protocol Revision: %d\n",
-		data.ProtocolRevision)
-	fmt.Printf("Message Length: %d\n",
-		data.Length)
-	for c, i := range data.Elements {
-		if c > 0 {
-			fmt.Println()
+	for _, fn := range flags.Args() {
+		raw, err := ioutil.ReadFile(fn)
+		if err != nil {
+			fmt.Fprintf(os.Stderr,
+				"error reading \"%s\": %s\n",
+				fn, err.Error())
+			continue
 		}
-		switch v := i.(type) {
-		case sdb.MOHeader:
-			fmt.Printf("\tMO Header IEI: %d\n",
-				v.IEI)
-			fmt.Printf("\tMO Header Length: %d\n",
-				v.Length)
-			fmt.Printf("\tMO Header CDR Reference: %d\n",
-				v.CDRReference)
-			fmt.Printf("\tMO Header IMEI: %s\n",
-				v.IMEI)
-			fmt.Printf("\tMO Header Status: %s (%d)\n",
-				v.StatusString(), v.Status)
-			fmt.Printf("\tMO Header MOMSN: %d\n",
-				v.MOMSN)
-			fmt.Printf("\tMO Header MTMSN: %d\n",
-				v.MTMSN)
-			fmt.Printf("\tMO Header Session Time: %s\n",
-				v.SessionTime().String())
 
-		case sdb.MOPayload:
-			fmt.Printf("\tMO Payload IEI: %d\n",
-				v.IEI)
-			fmt.Printf("\tMO Payload Length: %d\n",
-				v.Length)
+		data, err := sdb.ParseSDB(raw)
+		if err != nil {
+			fmt.Fprintf(os.Stderr,
+				"%s\n", err.Error())
+			continue
+		}
+
+		if *plonly {
+			for _, i := range data.Elements {
+				switch v := i.(type) {
+					case sdb.MOPayload:
+						os.Stdout.Write(v.Payload)
+				}
+			}
+		} else {
+			fmt.Printf("Protocol Revision: %d\n",
+				data.ProtocolRevision)
+			fmt.Printf("Message Length: %d\n",
+				data.Length)
+			for c, i := range data.Elements {
+				if c > 0 {
+					fmt.Println()
+				}
+				switch v := i.(type) {
+				case sdb.MOHeader:
+					fmt.Printf("\tMO Header IEI: %d\n",
+						v.IEI)
+					fmt.Printf("\tMO Header Length: %d\n",
+						v.Length)
+					fmt.Printf("\tMO Header CDR Reference: %d\n",
+						v.CDRReference)
+					fmt.Printf("\tMO Header IMEI: %s\n",
+						v.IMEI)
+					fmt.Printf("\tMO Header Status: %s (%d)\n",
+						v.StatusString(), v.Status)
+					fmt.Printf("\tMO Header MOMSN: %d\n",
+						v.MOMSN)
+					fmt.Printf("\tMO Header MTMSN: %d\n",
+						v.MTMSN)
+					fmt.Printf("\tMO Header Session Time: %s\n",
+						v.SessionTime().String())
+
+				case sdb.MOPayload:
+					fmt.Printf("\tMO Payload IEI: %d\n",
+						v.IEI)
+					fmt.Printf("\tMO Payload Length: %d\n",
+						v.Length)
 
-		case sdb.MOConfirmation:
-			fmt.Printf("\tMO Confirmation IEI: %d\n",
-				v.IEI)
-			fmt.Printf("\tMO Confirmation Length: %d\n",
-				v.Length)
-			fmt.Printf("\tMO Confirmation Status: %d\n",
-				v.Status)
+				case sdb.MOConfirmation:
+					fmt.Printf("\tMO Confirmation IEI: %d\n",
+						v.IEI)
+					fmt.Printf("\tMO Confirmation Length: %d\n",
+						v.Length)
+					fmt.Printf("\tMO Confirmation Status: %d\n",
+						v.Status)
+				}
+			}
 		}
 	}
 }