diff options
Diffstat (limited to 'Lib/gzip.py')
| -rw-r--r-- | Lib/gzip.py | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/Lib/gzip.py b/Lib/gzip.py index 8802adb0d9..36f9c36fd3 100644 --- a/Lib/gzip.py +++ b/Lib/gzip.py @@ -24,6 +24,10 @@ def U32(i): i += 1L << 32 return i +def LOWU32(i): + """Return the low-order 32 bits of an int, as a non-negative int.""" + return i & 0xFFFFFFFFL + def write32(output, value): output.write(struct.pack("<l", value)) @@ -295,21 +299,22 @@ class GzipFile: # We've read to the end of the file, so we have to rewind in order # to reread the 8 bytes containing the CRC and the file size. # We check the that the computed CRC and size of the - # uncompressed data matches the stored values. + # uncompressed data matches the stored values. Note that the size + # stored is the true file size mod 2**32. self.fileobj.seek(-8, 1) crc32 = read32(self.fileobj) isize = U32(read32(self.fileobj)) # may exceed 2GB if U32(crc32) != U32(self.crc): raise ValueError, "CRC check failed" - elif isize != self.size: + elif isize != LOWU32(self.size): raise ValueError, "Incorrect length of data produced" def close(self): if self.mode == WRITE: self.fileobj.write(self.compress.flush()) write32(self.fileobj, self.crc) - # self.size may exceed 2GB - write32u(self.fileobj, self.size) + # self.size may exceed 2GB, or even 4GB + write32u(self.fileobj, LOWU32(self.size)) self.fileobj = None elif self.mode == READ: self.fileobj = None |