Added append capability, #103
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jevans
parent
16ba90a372
commit
08ff86e4a2
2 changed files with 138 additions and 3 deletions
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@ -432,6 +432,42 @@ class Jp2k(Jp2kBox):
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# Refresh the metadata.
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self.parse()
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def append(self, box):
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"""Append a JP2 box to the file in-place.
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Parameters
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----------
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box : Jp2Box
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Instance of a JP2 box. Currently only XML boxes are allowed.
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"""
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if self._codec_format == opj2.CODEC_J2K:
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msg = "Only JP2 files can currently have boxes appended to them."
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raise IOError(msg)
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if box.box_id != 'xml ':
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raise IOError("Only XML boxes can currently be appended.")
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# Check the last box. If the length field is zero, then rewrite
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# the length field to reflect the true length of the box.
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with open(self.filename, 'rb') as ifile:
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offset = self.box[-1].offset
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ifile.seek(offset)
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read_buffer = ifile.read(4)
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box_length, = struct.unpack('>I', read_buffer)
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if box_length == 0:
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# Reopen the file in write mode and rewrite the length field.
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true_box_length = os.path.getsize(ifile.name) - offset
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with open(self.filename, 'r+b') as ofile:
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ofile.seek(offset)
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write_buffer = struct.pack('>I', true_box_length)
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ofile.write(write_buffer)
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# Can now safely append the box.
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with open(self.filename, 'ab') as ofile:
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box.write(ofile)
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self.parse()
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def wrap(self, filename, boxes=None):
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"""Write the codestream back out to file, wrapped in new JP2 jacket.
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@ -1133,6 +1169,7 @@ def _unpack_colorspace(colorspace, img_array, cparams):
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return colorspace
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def _populate_comptparms(img_array, cparams):
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"""Instantiate and populate comptparms structure.
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@ -1171,6 +1208,7 @@ def _populate_comptparms(img_array, cparams):
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return comptparms
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def _populate_image_struct(cparams, image, imgdata):
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"""Populates image struct needed for compression.
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@ -1203,6 +1241,7 @@ def _populate_image_struct(cparams, image, imgdata):
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return image
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def _validate_compression_params(img_array, cparams):
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"""Check that the compression parameters are valid.
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@ -1313,4 +1352,3 @@ class LibraryNotFoundError(IOError):
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"""
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def __init__(self, msg):
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IOError.__init__(self, msg)
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@ -18,8 +18,11 @@ Test suite specifically targeting JP2 box layout.
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import doctest
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import os
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import shutil
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import struct
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import sys
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import tempfile
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import uuid
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import xml.etree.cElementTree as ET
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if sys.hexversion < 0x02070000:
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@ -502,6 +505,100 @@ class TestColourSpecificationBox(unittest.TestCase):
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approximation=approx)
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@unittest.skipIf(glymur.lib.openjp2.OPENJP2 is None,
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"Missing openjp2 library.")
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class TestAppend(unittest.TestCase):
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"""Tests for append method."""
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def setUp(self):
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self.j2kfile = glymur.data.goodstuff()
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self.jp2file = glymur.data.nemo()
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def tearDown(self):
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pass
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def test_append_xml(self):
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"""Should be able to append an XML box."""
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with tempfile.NamedTemporaryFile(suffix=".jp2") as tfile:
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shutil.copyfile(self.jp2file, tfile.name)
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jp2 = Jp2k(tfile.name)
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the_xml = ET.fromstring('<?xml version="1.0"?><data>0</data>')
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xmlbox = glymur.jp2box.XMLBox(xml=the_xml)
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jp2.append(xmlbox)
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# The sequence of box IDs should be the same as before, but with an
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# xml box at the end.
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box_ids = [box.box_id for box in jp2.box]
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expected = ['jP ', 'ftyp', 'jp2h', 'uuid', 'uuid', 'jp2c', 'xml ']
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self.assertEqual(box_ids, expected)
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self.assertEqual(ET.tostring(jp2.box[-1].xml.getroot()),
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b'<data>0</data>')
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def test_only_jp2_allowed_to_append(self):
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"""Only JP2 files are allowed to be appended."""
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with tempfile.NamedTemporaryFile(suffix=".j2k") as tfile:
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shutil.copyfile(self.j2kfile, tfile.name)
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jp2 = Jp2k(tfile.name)
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# Make a UUID box.
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uuid_instance = uuid.UUID('00000000-0000-0000-0000-000000000000')
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data = b'0123456789'
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uuidbox = glymur.jp2box.UUIDBox(uuid_instance, data)
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with self.assertRaises(IOError):
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jp2.append(uuidbox)
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def test_length_field_is_zero(self):
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"""L=0 (length field in box header) is handled.
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L=0 implies that the containing box is the last box. If this is not
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handled properly, the appended box is never seen.
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"""
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baseline_jp2 = Jp2k(self.jp2file)
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with tempfile.NamedTemporaryFile(suffix='.jp2') as tfile:
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with open(self.jp2file, 'rb') as ifile:
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# Everything up until the jp2c box.
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offset = baseline_jp2.box[-1].offset
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tfile.write(ifile.read(offset))
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# Write the L, T fields of the jp2c box such that L == 0
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write_buffer = struct.pack('>I4s', int(0), b'jp2c')
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tfile.write(write_buffer)
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# Write out the rest of the codestream.
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ifile.seek(offset+8)
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tfile.write(ifile.read())
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tfile.flush()
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jp2 = Jp2k(tfile.name)
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the_xml = ET.fromstring('<?xml version="1.0"?><data>0</data>')
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xmlbox = glymur.jp2box.XMLBox(xml=the_xml)
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jp2.append(xmlbox)
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# The sequence of box IDs should be the same as before, but with an
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# xml box at the end.
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box_ids = [box.box_id for box in jp2.box]
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expected = ['jP ', 'ftyp', 'jp2h', 'uuid', 'uuid', 'jp2c', 'xml ']
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self.assertEqual(box_ids, expected)
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self.assertEqual(ET.tostring(jp2.box[-1].xml.getroot()),
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b'<data>0</data>')
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def test_only_xml_allowed_to_append(self):
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"""Only XML boxes are allowed to be appended."""
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with tempfile.NamedTemporaryFile(suffix=".jp2") as tfile:
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shutil.copyfile(self.jp2file, tfile.name)
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jp2 = Jp2k(tfile.name)
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# Make a UUID box.
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uuid_instance = uuid.UUID('00000000-0000-0000-0000-000000000000')
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data = b'0123456789'
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uuidbox = glymur.jp2box.UUIDBox(uuid_instance, data)
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with self.assertRaises(IOError):
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jp2.append(uuidbox)
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@unittest.skipIf(glymur.lib.openjp2.OPENJP2 is None,
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"Missing openjp2 library.")
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class TestWrap(unittest.TestCase):
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@ -703,7 +800,7 @@ class TestJp2Boxes(unittest.TestCase):
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def test_default_ihdr(self):
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"""Should be able to instantiate an image header box."""
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ihdr = glymur.jp2box.ImageHeaderBox(height=512, width=256,
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num_components=3)
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num_components=3)
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self.assertEqual(ihdr.height, 512)
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self.assertEqual(ihdr.width, 256)
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self.assertEqual(ihdr.num_components, 3)
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@ -715,7 +812,7 @@ class TestJp2Boxes(unittest.TestCase):
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"""Should be able to set jp2h boxes."""
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box = JP2HeaderBox()
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box.box = [ImageHeaderBox(height=512, width=256),
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ColourSpecificationBox(colorspace=glymur.core.GREYSCALE)]
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ColourSpecificationBox(colorspace=glymur.core.GREYSCALE)]
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self.assertTrue(True)
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def test_default_ccodestreambox(self):
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