diff --git a/glymur/jp2k.py b/glymur/jp2k.py index ea8ef5e..d5c604c 100644 --- a/glymur/jp2k.py +++ b/glymur/jp2k.py @@ -432,6 +432,42 @@ class Jp2k(Jp2kBox): # Refresh the metadata. self.parse() + def append(self, box): + """Append a JP2 box to the file in-place. + + Parameters + ---------- + box : Jp2Box + Instance of a JP2 box. Currently only XML boxes are allowed. + """ + if self._codec_format == opj2.CODEC_J2K: + msg = "Only JP2 files can currently have boxes appended to them." + raise IOError(msg) + + if box.box_id != 'xml ': + raise IOError("Only XML boxes can currently be appended.") + + # Check the last box. If the length field is zero, then rewrite + # the length field to reflect the true length of the box. + with open(self.filename, 'rb') as ifile: + offset = self.box[-1].offset + ifile.seek(offset) + read_buffer = ifile.read(4) + box_length, = struct.unpack('>I', read_buffer) + if box_length == 0: + # Reopen the file in write mode and rewrite the length field. + true_box_length = os.path.getsize(ifile.name) - offset + with open(self.filename, 'r+b') as ofile: + ofile.seek(offset) + write_buffer = struct.pack('>I', true_box_length) + ofile.write(write_buffer) + + # Can now safely append the box. + with open(self.filename, 'ab') as ofile: + box.write(ofile) + + self.parse() + def wrap(self, filename, boxes=None): """Write the codestream back out to file, wrapped in new JP2 jacket. @@ -1133,6 +1169,7 @@ def _unpack_colorspace(colorspace, img_array, cparams): return colorspace + def _populate_comptparms(img_array, cparams): """Instantiate and populate comptparms structure. @@ -1171,6 +1208,7 @@ def _populate_comptparms(img_array, cparams): return comptparms + def _populate_image_struct(cparams, image, imgdata): """Populates image struct needed for compression. @@ -1203,6 +1241,7 @@ def _populate_image_struct(cparams, image, imgdata): return image + def _validate_compression_params(img_array, cparams): """Check that the compression parameters are valid. @@ -1313,4 +1352,3 @@ class LibraryNotFoundError(IOError): """ def __init__(self, msg): IOError.__init__(self, msg) - diff --git a/glymur/test/test_jp2box.py b/glymur/test/test_jp2box.py index 15c0209..71dbd72 100644 --- a/glymur/test/test_jp2box.py +++ b/glymur/test/test_jp2box.py @@ -18,8 +18,11 @@ Test suite specifically targeting JP2 box layout. import doctest import os +import shutil +import struct import sys import tempfile +import uuid import xml.etree.cElementTree as ET if sys.hexversion < 0x02070000: @@ -502,6 +505,100 @@ class TestColourSpecificationBox(unittest.TestCase): approximation=approx) +@unittest.skipIf(glymur.lib.openjp2.OPENJP2 is None, + "Missing openjp2 library.") +class TestAppend(unittest.TestCase): + """Tests for append method.""" + + def setUp(self): + self.j2kfile = glymur.data.goodstuff() + self.jp2file = glymur.data.nemo() + + def tearDown(self): + pass + + def test_append_xml(self): + """Should be able to append an XML box.""" + with tempfile.NamedTemporaryFile(suffix=".jp2") as tfile: + shutil.copyfile(self.jp2file, tfile.name) + + jp2 = Jp2k(tfile.name) + the_xml = ET.fromstring('0') + xmlbox = glymur.jp2box.XMLBox(xml=the_xml) + jp2.append(xmlbox) + + # The sequence of box IDs should be the same as before, but with an + # xml box at the end. + box_ids = [box.box_id for box in jp2.box] + expected = ['jP ', 'ftyp', 'jp2h', 'uuid', 'uuid', 'jp2c', 'xml '] + self.assertEqual(box_ids, expected) + self.assertEqual(ET.tostring(jp2.box[-1].xml.getroot()), + b'0') + + def test_only_jp2_allowed_to_append(self): + """Only JP2 files are allowed to be appended.""" + with tempfile.NamedTemporaryFile(suffix=".j2k") as tfile: + shutil.copyfile(self.j2kfile, tfile.name) + + jp2 = Jp2k(tfile.name) + + # Make a UUID box. + uuid_instance = uuid.UUID('00000000-0000-0000-0000-000000000000') + data = b'0123456789' + uuidbox = glymur.jp2box.UUIDBox(uuid_instance, data) + with self.assertRaises(IOError): + jp2.append(uuidbox) + + def test_length_field_is_zero(self): + """L=0 (length field in box header) is handled. + + L=0 implies that the containing box is the last box. If this is not + handled properly, the appended box is never seen. + """ + baseline_jp2 = Jp2k(self.jp2file) + with tempfile.NamedTemporaryFile(suffix='.jp2') as tfile: + with open(self.jp2file, 'rb') as ifile: + # Everything up until the jp2c box. + offset = baseline_jp2.box[-1].offset + tfile.write(ifile.read(offset)) + + # Write the L, T fields of the jp2c box such that L == 0 + write_buffer = struct.pack('>I4s', int(0), b'jp2c') + tfile.write(write_buffer) + + # Write out the rest of the codestream. + ifile.seek(offset+8) + tfile.write(ifile.read()) + tfile.flush() + + jp2 = Jp2k(tfile.name) + the_xml = ET.fromstring('0') + xmlbox = glymur.jp2box.XMLBox(xml=the_xml) + jp2.append(xmlbox) + + # The sequence of box IDs should be the same as before, but with an + # xml box at the end. + box_ids = [box.box_id for box in jp2.box] + expected = ['jP ', 'ftyp', 'jp2h', 'uuid', 'uuid', 'jp2c', 'xml '] + self.assertEqual(box_ids, expected) + self.assertEqual(ET.tostring(jp2.box[-1].xml.getroot()), + b'0') + + def test_only_xml_allowed_to_append(self): + """Only XML boxes are allowed to be appended.""" + with tempfile.NamedTemporaryFile(suffix=".jp2") as tfile: + shutil.copyfile(self.jp2file, tfile.name) + + jp2 = Jp2k(tfile.name) + + # Make a UUID box. + uuid_instance = uuid.UUID('00000000-0000-0000-0000-000000000000') + data = b'0123456789' + uuidbox = glymur.jp2box.UUIDBox(uuid_instance, data) + with self.assertRaises(IOError): + jp2.append(uuidbox) + + @unittest.skipIf(glymur.lib.openjp2.OPENJP2 is None, "Missing openjp2 library.") class TestWrap(unittest.TestCase): @@ -703,7 +800,7 @@ class TestJp2Boxes(unittest.TestCase): def test_default_ihdr(self): """Should be able to instantiate an image header box.""" ihdr = glymur.jp2box.ImageHeaderBox(height=512, width=256, - num_components=3) + num_components=3) self.assertEqual(ihdr.height, 512) self.assertEqual(ihdr.width, 256) self.assertEqual(ihdr.num_components, 3) @@ -715,7 +812,7 @@ class TestJp2Boxes(unittest.TestCase): """Should be able to set jp2h boxes.""" box = JP2HeaderBox() box.box = [ImageHeaderBox(height=512, width=256), - ColourSpecificationBox(colorspace=glymur.core.GREYSCALE)] + ColourSpecificationBox(colorspace=glymur.core.GREYSCALE)] self.assertTrue(True) def test_default_ccodestreambox(self):