Added support for Data Reference box.

CHANGES.txt

@@ -1,6 +1,6 @@
-Jan 29, 2014 - Added read support for JPX FreeBox, NumberListBox.  Palette box
+Feb 01, 2014 - Added read support for JPX FreeBox, NumberListBox, Data Reference
-    now a 2D numpy array instead of a list of 1D arrays.  JP2 super box
+    Box.  Palette box now a 2D numpy array instead of a list of 1D arrays.
-    constructors now take optional box list  argument.
+    JP2 super box constructors now take optional box list  argument.
 
 Jan 28, 2014 - v0.5.10  Fixed bad warning when reader requirements box mask
     length is unsupported.

glymur/jp2box.py

@@ -811,6 +811,75 @@ class ContiguousCodestreamBox(Jp2kBox):
         return box
 
 
+class DataReferenceBox(Jp2kBox):
+    """Container for Data Reference box information.
+
+    Attributes
+    ----------
+    box_id : str
+        4-character identifier for the box.
+    length : int
+        length of the box in bytes.
+    offset : int
+        offset of the box from the start of the file.
+    longname : str
+        more verbose description of the box.
+    DR : list
+        Data Entry URL boxes.
+    """
+    def __init__(self, data_entry_url_boxes, length=0, offset=-1):
+        Jp2kBox.__init__(self, box_id='dtbl', longname='Data Reference')
+        self.DR = data_entry_url_boxes
+        self.length = length
+        self.offset = offset
+
+    def __str__(self):
+        msg = Jp2kBox.__str__(self)
+        for box in enumerate(self.DR):
+            msg += '\n    ' + str(box)
+        return msg
+
+    def __repr__(self):
+        msg = 'glymur.jp2box.DataReferenceBox()'
+        return msg
+
+    @staticmethod
+    def parse(fptr, offset, length):
+        """Parse Label box.
+
+        Parameters
+        ----------
+        fptr : file
+            Open file object.
+        offset : int
+            Start position of box in bytes.
+        length : int
+            Length of the box in bytes.
+
+        Returns
+        -------
+        DataReferenceBox instance
+        """
+        # Read the number of data references
+        read_buffer = fptr.read(2)
+        ndr, = struct.unpack('>H', read_buffer)
+
+        # Read each data entry url box.
+        data_entry_url_box_list = []
+        for _ in range(ndr):
+            start = fptr.tell()
+            read_buffer = fptr.read(8)
+            (box_length, box_id) = struct.unpack('>I4s', read_buffer)
+            if sys.hexversion >= 0x03000000:
+                box_id = box_id.decode('utf-8')
+
+            box = DataEntryURLBox.parse(fptr, start, box_length)
+            data_entry_url_box_list.append(box)
+
+        return DataReferenceBox(data_entry_url_box_list,
+                                length=length, offset=offset)
+
+
 class FileTypeBox(Jp2kBox):
     """Container for JPEG 2000 file type box information.
 
@@ -2922,6 +2991,7 @@ _BOX_WITH_ID = {
     'cdef': ChannelDefinitionBox,
     'cmap': ComponentMappingBox,
     'colr': ColourSpecificationBox,
+    'dtbl': DataReferenceBox,
     'ftyp': FileTypeBox,
     'ihdr': ImageHeaderBox,
     'jP  ': JPEG2000SignatureBox,

glymur/test/test_jp2box_jpx.py

@@ -8,7 +8,6 @@ import struct
 import sys
 import tempfile
 import warnings
-import xml.etree.cElementTree as ET
 
 if sys.hexversion < 0x02070000:
     import unittest2 as unittest
@@ -17,7 +16,6 @@ else:
 
 import glymur
 from glymur import Jp2k
-from glymur.jp2box import ReaderRequirementsBox
 
 
 @unittest.skipIf(sys.hexversion < 0x03000000, "Warning assert on 2.x.")
@@ -27,7 +25,6 @@ class TestJPXOther(unittest.TestCase):
 
     def setUp(self):
         self.jpxfile = glymur.data.jpxfile()
-        pass
 
     def tearDown(self):
         pass
@@ -51,6 +48,40 @@ class TestJPXOther(unittest.TestCase):
         self.assertEqual(j.box[16].box[0].box_id, 'free')
         self.assertEqual(type(j.box[16].box[0]), glymur.jp2box.FreeBox)
 
+    def test_dtbl(self):
+        """Verify that we can interpret Data Reference boxes."""
+        # Copy the existing JPX file, add a data reference box onto the end.
+        with tempfile.NamedTemporaryFile(suffix='.jpx') as tfile:
+            with open(self.jpxfile, 'rb') as ifile:
+                tfile.write(ifile.read())
+            write_buffer = struct.pack('>I4s', 50, b'dtbl')
+            tfile.write(write_buffer)
+
+            # Just two boxes.
+            write_buffer = struct.pack('>H', 2)
+            tfile.write(write_buffer)
+
+            # First data entry url box.
+            write_buffer = struct.pack('>I4s', 20, b'url ')
+            tfile.write(write_buffer)
+            write_buffer = struct.pack('>BBBB8s', 0, 0, 0, 0, b'file:///')
+            tfile.write(write_buffer)
+
+            # Second data entry url box.
+            write_buffer = struct.pack('>I4s', 20, b'url ')
+            tfile.write(write_buffer)
+            write_buffer = struct.pack('>BBBB8s', 0, 0, 0, 0, b'file:///')
+            tfile.write(write_buffer)
+
+            tfile.flush()
+
+            with self.assertWarns(UserWarning):
+                jpx = Jp2k(tfile.name)
+
+            self.assertEqual(jpx.box[-1].box_id, 'dtbl')
+            self.assertEqual(len(jpx.box[-1].DR), 2)
+
+
     def test_nlst(self):
         """Verify that we can handle a free box."""
         with warnings.catch_warnings():