fix up some OSC string parsing issues and test for them

message.go

@@ -44,6 +44,11 @@ func MessageFromBytes(bytes []byte) (*OSCMessage, error) {
 		Args:    []OSCArg{},
 	}
 
+	if len(typeAndArgBytes) == 0 {
+		// NOTE(jwetzell): no type string return early.
+		return &oscMessage, nil
+	}
+
 	typeString, argBytes, err := readOSCString(typeAndArgBytes)
 
 	if err != nil {
@@ -56,9 +61,9 @@ func MessageFromBytes(bytes []byte) (*OSCMessage, error) {
 				return nil, errors.New("type string is malformed")
 			}
 		} else {
-			oscArg, remainingBytes, error := readOSCArg(argBytes, string(oscType))
-			if error != nil {
-				return nil, error
+			oscArg, remainingBytes, err := readOSCArg(argBytes, string(oscType))
+			if err != nil {
+				return nil, err
 			}
 			argBytes = remainingBytes
 			oscMessage.Args = append(oscMessage.Args, oscArg)

message_test.go

@@ -298,18 +298,32 @@ func TestBadOSCMessageDecoding(t *testing.T) {
 		{
 			name:        "address string not padded",
 			bytes:       []byte{47, 104, 101, 108, 108, 111, 0},
-			errorString: "string data is not properly padded",
+			errorString: "OSC string is not properly padded",
 		},
 		{
 			name:        "type string not padded",
 			bytes:       []byte{47, 104, 101, 108, 108, 111, 0, 0, 44, 0},
-			errorString: "string data is not properly padded",
+			errorString: "OSC string is not properly padded",
 		},
 		{
 			name:        "type string does not start with ,",
 			bytes:       []byte{47, 104, 101, 108, 108, 111, 0, 0, 45, 0, 0, 0},
 			errorString: "type string is malformed",
 		},
+		{
+			name: "string arg not null-terminated",
+			bytes: []byte{
+				47, 104, 101, 108, 108, 111, 0, 0, 44, 115, 0, 0, 97, 114, 103, 49,
+			},
+			errorString: "OSC string must be null-terminated",
+		},
+		{
+			name: "string arg not padded",
+			bytes: []byte{
+				47, 104, 101, 108, 108, 111, 0, 0, 44, 115, 0, 0, 104, 105, 0,
+			},
+			errorString: "OSC string is not properly padded",
+		},
 	}
 
 	for _, testCase := range testCases {

osc.go

@@ -172,18 +172,23 @@ func argsToBuffer(args []OSCArg) []byte {
 }
 
 func readOSCString(bytes []byte) (string, []byte, error) {
-	//TODO(jwetzell): add error handling
 	oscString := ""
 	stringEndIndex := 0
 
+	nullByteFound := false
 	for index, byteIn := range bytes {
 		if byteIn == 0 {
+			nullByteFound = true
 			oscString = string(bytes[0:index])
 			stringEndIndex = index + 1
 			break
 		}
 	}
 
+	if !nullByteFound {
+		return "", bytes, errors.New("OSC string must be null-terminated")
+	}
+
 	stringPadding := 4 - (stringEndIndex % 4)
 
 	if stringPadding < 4 {
@@ -191,7 +196,7 @@ func readOSCString(bytes []byte) (string, []byte, error) {
 	}
 
 	if stringEndIndex > len(bytes) {
-		return "", bytes, errors.New("string data is not properly padded")
+		return "", bytes, errors.New("OSC string is not properly padded")
 	}
 
 	remainingBytes := bytes[stringEndIndex:]