FileType box sanity checks. #175

glymur/jp2box.py

@@ -1046,9 +1046,22 @@ class FileTypeBox(Jp2kBox):
 
         return msg
 
+    def _validate(self):
+        """Validate the box before writing to file."""
+        if self.brand not in ['jp2 ', 'jpx ']:
+            msg = "The file type brand must be either 'jp2 ' or 'jpx '."
+            raise IOError(msg)
+        valid_cls = ['jp2 ', 'jpx ', 'jpxb']
+        for item in self.compatibility_list:
+            if item not in valid_cls:
+                msg = "The file type compatibility list item '{0}' is not "
+                msg += "valid:  valid entries are {1}"
+                raise IOError(msg.format(item, valid_cls))
+
     def write(self, fptr):
         """Write a File Type box to file.
         """
+        self._validate()
         length = 16 + 4*len(self.compatibility_list)
         fptr.write(struct.pack('>I', length))
         fptr.write('ftyp'.encode())

glymur/test/test_jp2box.py

@@ -340,6 +340,29 @@ class TestChannelDefinition(unittest.TestCase):
                                                association=association)
 
 
+class TestFileTypeBox(unittest.TestCase):
+    """Test suite for ftyp box issues."""
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def test_brand_unknown(self):
+        """A ftyp box brand must be 'jp2 ' or 'jpx '."""
+        ftyp = glymur.jp2box.FileTypeBox(brand='jp3')
+        with self.assertRaises(IOError):
+            with tempfile.TemporaryFile() as tfile:
+                ftyp.write(tfile) 
+
+    def test_cl_entry_unknown(self):
+        """A ftyp box cl list can only contain 'jp2 ', 'jpx ', or 'jpxb'."""
+        ftyp = glymur.jp2box.FileTypeBox(compatibility_list=['jp3'])
+        with self.assertRaises(IOError):
+            with tempfile.TemporaryFile() as tfile:
+                ftyp.write(tfile) 
+
 class TestColourSpecificationBox(unittest.TestCase):
     """Test suite for colr box instantiation."""