A stab in the dark attempt to fix the alpha/tru64 buildbot problem and add more
test coverage of valid inputs to zlib.crc32.
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 92fdb7b..4991ae1 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -420,7 +420,7 @@
except ImportError:
raise CompressionError("zlib module is not available")
self.zlib = zlib
- self.crc = zlib.crc32("")
+ self.crc = zlib.crc32("") & 0xffffffffL
if mode == "r":
self._init_read_gz()
else:
@@ -458,7 +458,7 @@
"""Write string s to the stream.
"""
if self.comptype == "gz":
- self.crc = self.zlib.crc32(s, self.crc)
+ self.crc = self.zlib.crc32(s, self.crc) & 0xffffffffL
self.pos += len(s)
if self.comptype != "tar":
s = self.cmp.compress(s)
diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
index 9f0fe18..0c96842 100644
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -53,6 +53,15 @@
self.assertEqual(binascii.crc32(foo), zlib.crc32(foo))
self.assertEqual(binascii.crc32('spam'), zlib.crc32('spam'))
+ def test_negative_crc_iv_input(self):
+ # The range of valid input values for the crc state should be
+ # -2**31 through 2**32-1 to allow inputs artifically constrained
+ # to a signed 32-bit integer.
+ self.assertEqual(zlib.crc32('ham', -1), zlib.crc32('ham', 0xffffffffL))
+ self.assertEqual(zlib.crc32('spam', -3141593),
+ zlib.crc32('spam', 0xffd01027L))
+ self.assertEqual(zlib.crc32('spam', -(2**31)),
+ zlib.crc32('spam', (2**31)))
class ExceptionTestCase(unittest.TestCase):