Treat Unknown Tags with defined VL as OW

pkg/tag/tag.go

@@ -128,7 +128,7 @@ func GetVRKind(tag Tag, vr string) VRKind {
 		return VRDate
 	case "AT":
 		return VRTagList
-	case "OW", "OB":
+	case "OW", "OB", "UN":
 		return VRBytes
 	case "LT", "UT":
 		return VRString

read.go

@@ -422,7 +422,7 @@ func readSequenceItem(r dicomio.Reader, t tag.Tag, vr string, vl uint32) (Value,
 
 func readBytes(r dicomio.Reader, t tag.Tag, vr string, vl uint32) (Value, error) {
 	// TODO: add special handling of PixelData
-	if vr == vrraw.OtherByte {
+	if vr == vrraw.OtherByte || vr == vrraw.Unknown {
 		data := make([]byte, vl)
 		_, err := io.ReadFull(r, data)
 		return &bytesValue{value: data}, err
@@ -466,7 +466,6 @@ func readString(r dicomio.Reader, t tag.Tag, vr string, vl uint32) (Value, error
 
 	// Split multiple strings
 	strs := strings.Split(str, "\\")
-
 	return &stringsValue{value: strs}, err
 }
 

read_test.go

@@ -168,12 +168,19 @@ func TestReadOWBytes(t *testing.T) {
 		expectedErr error
 	}{
 		{
-			name:        "even-number bytes",
+			name:        "OW VR with even-number bytes",
 			bytes:       []byte{0x1, 0x2, 0x3, 0x4},
 			VR:          vrraw.OtherWord,
 			want:        &bytesValue{value: []byte{0x1, 0x2, 0x3, 0x4}},
 			expectedErr: nil,
 		},
+		{
+			name:        "UN VR even-number bytes",
+			bytes:       []byte{0x1, 0x2, 0x3, 0x4},
+			VR:          vrraw.Unknown,
+			want:        &bytesValue{value: []byte{0x1, 0x2, 0x3, 0x4}},
+			expectedErr: nil,
+		},
 		{
 			name:        "error on odd-number bytes",
 			bytes:       []byte{0x1, 0x2, 0x3},

write.go

@@ -313,7 +313,7 @@ func verifyValueType(t tag.Tag, value Value, vr string) error {
 		ok = valueType == Sequences
 	case "NA":
 		ok = valueType == SequenceItem
-	case vrraw.OtherWord, vrraw.OtherByte:
+	case vrraw.OtherWord, vrraw.OtherByte, vrraw.Unknown:
 		if t == tag.PixelData {
 			ok = valueType == PixelData
 		} else {
@@ -488,7 +488,7 @@ func writeStrings(w dicomio.Writer, values []string, vr string) error {
 func writeBytes(w dicomio.Writer, values []byte, vr string) error {
 	var err error
 	switch vr {
-	case vrraw.OtherWord:
+	case vrraw.OtherWord, vrraw.Unknown:
 		err = writeOtherWordString(w, values)
 	case vrraw.OtherByte:
 		err = writeOtherByteString(w, values)

write_test.go

@@ -47,6 +47,17 @@ func TestWrite(t *testing.T) {
 				mustNewElement(tag.FloatingPointValue, []float64{128.10}),
 				mustNewElement(tag.DimensionIndexPointer, []int{32, 36950}),
 				mustNewElement(tag.RedPaletteColorLookupTableData, []byte{0x1, 0x2, 0x3, 0x4}),
+				mustNewElement(tag.SelectorSLValue, []int{-20}),
+				// Some tag with an unknown VR.
+				{
+					Tag:                    tag.Tag{0x0019, 0x1027},
+					ValueRepresentation:    tag.VRBytes,
+					RawValueRepresentation: "UN",
+					ValueLength:            4,
+					Value: &bytesValue{
+						value: []byte{0x1, 0x2, 0x3, 0x4},
+					},
+				},
 			}},
 			expectedError: nil,
 		},