Checking for proper location of jp2h children. #157

Certain boxes can only reside in jp2h or jpch (which is not currently
supported for writing purposed).

glymur/jp2k.py

@@ -1198,6 +1198,22 @@ def _validate_jp2_box_sequence(boxes):
     _jpx_compatibility(boxes, boxes[1].compatibility_list)
     _check_for_singletons(boxes)
     _check_top_level(boxes)
+    _check_jp2h_child_boxes(boxes, 'top-level')
+
+JP2H_CHILDREN = set(['bpcc', 'cmap', 'ihdr', 'pclr'])
+def _check_jp2h_child_boxes(boxes, parent_box_name):
+    """Certain boxes can only reside in the JP2 header."""
+    box_ids = set([box.box_id for box in boxes])
+    intersection = box_ids.intersection(JP2H_CHILDREN)
+    if len(intersection) > 0 and parent_box_name != 'jp2h':
+        msg = "A '{0}' box can only be nested in a JP2 header box."
+        raise IOError(msg.format(list(intersection)[0]))
+
+    # Recursively check any contained superboxes.
+    for box in boxes:
+        if hasattr(box, 'box'):
+            _check_jp2h_child_boxes(box.box, box.box_id)
+
 
 def _collect_box_count(boxes):
     """Count the occurences of each box type."""

glymur/test/test_jp2box.py

@@ -679,6 +679,33 @@ class TestWrap(unittest.TestCase):
             with self.assertRaises(IOError):
                 j2k.wrap(tfile.name, boxes=boxes)
 
+    def test_pclr_not_in_jp2h(self):
+        """A palette box must reside in a JP2 header box."""
+        palette = np.array([[255, 0, 255], [0, 255, 0]], dtype=np.int32)
+        bps = (8, 8, 8)
+        signed = (True, False, True)
+        pclr = glymur.jp2box.PaletteBox(palette=palette, bits_per_component=bps,
+                                        signed=(True, False, True))
+
+        j2k = Jp2k(self.j2kfile)
+        codestream = j2k.get_codestream()
+        height = codestream.segment[1].ysiz
+        width = codestream.segment[1].xsiz
+        num_components = len(codestream.segment[1].xrsiz)
+
+        jp2b = JPEG2000SignatureBox()
+        ftyp = FileTypeBox()
+        jp2h = JP2HeaderBox()
+        jp2c = ContiguousCodestreamBox()
+        colr = ColourSpecificationBox(colorspace=glymur.core.SRGB)
+        ihdr = ImageHeaderBox(height=height, width=width,
+                              num_components=num_components)
+        jp2h.box = [ihdr, colr]
+        boxes = [jp2b, ftyp, jp2h, jp2c, pclr]
+        with tempfile.NamedTemporaryFile(suffix=".jp2") as tfile:
+            with self.assertRaises(IOError):
+                j2k.wrap(tfile.name, boxes=boxes)
+
     def test_jp2h_not_preceeding_jp2c(self):
         """jp2h must precede jp2c"""
         j2k = Jp2k(self.j2kfile)