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Merge pull request #3980 from kkopachev/exif-writing-fixes

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Exif writing fixes: Rational boundaries and signed/unsigned types
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Andrew Murray 2019-12-31 19:36:31 +11:00 committed by GitHub
commit 066cc1b2c7
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2 changed files with 115 additions and 14 deletions
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94
Tests/test_file_tiff_metadata.py
View File

@ -2,7 +2,7 @@ import io
import struct
from PIL import Image, TiffImagePlugin, TiffTags
from PIL.TiffImagePlugin import IFDRational, _limit_rational
from PIL.TiffImagePlugin import IFDRational
from .helper import PillowTestCase, hopper
@ -139,14 +139,6 @@ class TestFileTiffMetadata(PillowTestCase):
with Image.open(f) as loaded:
reloaded = loaded.tag_v2.named()
for k, v in original.items():
if isinstance(v, IFDRational):
original[k] = IFDRational(*_limit_rational(v, 2 ** 31))
elif isinstance(v, tuple) and isinstance(v[0], IFDRational):
original[k] = tuple(
IFDRational(*_limit_rational(elt, 2 ** 31)) for elt in v
)
ignored = ["StripByteCounts", "RowsPerStrip", "PageNumber", "StripOffsets"]
for tag, value in reloaded.items():
@ -225,6 +217,90 @@ class TestFileTiffMetadata(PillowTestCase):
self.assertEqual(0, reloaded.tag_v2[41988].numerator)
self.assertEqual(0, reloaded.tag_v2[41988].denominator)
def test_ifd_unsigned_rational(self):
im = hopper()
info = TiffImagePlugin.ImageFileDirectory_v2()
max_long = 2 ** 32 - 1
# 4 bytes unsigned long
numerator = max_long
info[41493] = TiffImagePlugin.IFDRational(numerator, 1)
out = self.tempfile("temp.tiff")
im.save(out, tiffinfo=info, compression="raw")
reloaded = Image.open(out)
self.assertEqual(max_long, reloaded.tag_v2[41493].numerator)
self.assertEqual(1, reloaded.tag_v2[41493].denominator)
# out of bounds of 4 byte unsigned long
numerator = max_long + 1
info[41493] = TiffImagePlugin.IFDRational(numerator, 1)
out = self.tempfile("temp.tiff")
im.save(out, tiffinfo=info, compression="raw")
reloaded = Image.open(out)
self.assertEqual(max_long, reloaded.tag_v2[41493].numerator)
self.assertEqual(1, reloaded.tag_v2[41493].denominator)
def test_ifd_signed_rational(self):
im = hopper()
info = TiffImagePlugin.ImageFileDirectory_v2()
# pair of 4 byte signed longs
numerator = 2 ** 31 - 1
denominator = -(2 ** 31)
info[37380] = TiffImagePlugin.IFDRational(numerator, denominator)
out = self.tempfile("temp.tiff")
im.save(out, tiffinfo=info, compression="raw")
reloaded = Image.open(out)
self.assertEqual(numerator, reloaded.tag_v2[37380].numerator)
self.assertEqual(denominator, reloaded.tag_v2[37380].denominator)
numerator = -(2 ** 31)
denominator = 2 ** 31 - 1
info[37380] = TiffImagePlugin.IFDRational(numerator, denominator)
out = self.tempfile("temp.tiff")
im.save(out, tiffinfo=info, compression="raw")
reloaded = Image.open(out)
self.assertEqual(numerator, reloaded.tag_v2[37380].numerator)
self.assertEqual(denominator, reloaded.tag_v2[37380].denominator)
# out of bounds of 4 byte signed long
numerator = -(2 ** 31) - 1
denominator = 1
info[37380] = TiffImagePlugin.IFDRational(numerator, denominator)
out = self.tempfile("temp.tiff")
im.save(out, tiffinfo=info, compression="raw")
reloaded = Image.open(out)
self.assertEqual(2 ** 31 - 1, reloaded.tag_v2[37380].numerator)
self.assertEqual(-1, reloaded.tag_v2[37380].denominator)
def test_ifd_signed_long(self):
im = hopper()
info = TiffImagePlugin.ImageFileDirectory_v2()
info[37000] = -60000
out = self.tempfile("temp.tiff")
im.save(out, tiffinfo=info, compression="raw")
reloaded = Image.open(out)
self.assertEqual(reloaded.tag_v2[37000], -60000)
def test_empty_values(self):
data = io.BytesIO(
b"II*\x00\x08\x00\x00\x00\x03\x00\x1a\x01\x05\x00\x00\x00\x00\x00"

35
src/PIL/TiffImagePlugin.py
View File

@ -263,6 +263,20 @@ def _limit_rational(val, max_val):
return n_d[::-1] if inv else n_d
def _limit_signed_rational(val, max_val, min_val):
frac = Fraction(val)
n_d = frac.numerator, frac.denominator
if min(n_d) < min_val:
n_d = _limit_rational(val, abs(min_val))
if max(n_d) > max_val:
val = Fraction(*n_d)
n_d = _limit_rational(val, max_val)
return n_d
##
# Wrapper for TIFF IFDs.
@ -520,12 +534,22 @@ class ImageFileDirectory_v2(MutableMapping):
else:
self.tagtype[tag] = TiffTags.UNDEFINED
if all(isinstance(v, IFDRational) for v in values):
self.tagtype[tag] = TiffTags.RATIONAL
self.tagtype[tag] = (
TiffTags.RATIONAL
if all(v >= 0 for v in values)
else TiffTags.SIGNED_RATIONAL
)
elif all(isinstance(v, int) for v in values):
if all(v < 2 ** 16 for v in values):
if all(0 <= v < 2 ** 16 for v in values):
self.tagtype[tag] = TiffTags.SHORT
elif all(-(2 ** 15) < v < 2 ** 15 for v in values):
self.tagtype[tag] = TiffTags.SIGNED_SHORT
else:
self.tagtype[tag] = TiffTags.LONG
self.tagtype[tag] = (
TiffTags.LONG
if all(v >= 0 for v in values)
else TiffTags.SIGNED_LONG
)
elif all(isinstance(v, float) for v in values):
self.tagtype[tag] = TiffTags.DOUBLE
else:
@ -666,7 +690,7 @@ class ImageFileDirectory_v2(MutableMapping):
@_register_writer(5)
def write_rational(self, *values):
return b"".join(
self._pack("2L", *_limit_rational(frac, 2 ** 31)) for frac in values
self._pack("2L", *_limit_rational(frac, 2 ** 32 - 1)) for frac in values
)
@_register_loader(7, 1)
@ -689,7 +713,8 @@ class ImageFileDirectory_v2(MutableMapping):
@_register_writer(10)
def write_signed_rational(self, *values):
return b"".join(
self._pack("2L", *_limit_rational(frac, 2 ** 30)) for frac in values
self._pack("2l", *_limit_signed_rational(frac, 2 ** 31 - 1, -(2 ** 31)))
for frac in values
)
def _ensure_read(self, fp, size):