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  • Committer: Robert Collins
  • Date: 2006-04-20 04:52:19 UTC
  • mto: (1711.1.1 integration)
  • mto: This revision was merged to the branch mainline in revision 1677.
  • Revision ID: robertc@robertcollins.net-20060420045219-440c2336c88c5d0e
Really fix short-read support in tuned_gzip. The python zlib module behaved differently than thought.

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bzrlib/tuned_gzip.py
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        if buf == "":
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            self._add_read_data(self.decompress.flush())
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            assert len(self.decompress.unused_data) >= 8, "what does flush do?"
 
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            self._gzip_tail = self.decompress.unused_data[0:8]
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            self._read_eof()
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            # tell the driving read() call we have stuffed all the data
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            # in self.extrabuf
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            if seek_length > 0:
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                # we read too much data
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                self.fileobj.seek(-seek_length, 1)
 
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                self._gzip_tail = self.decompress.unused_data[0:8]
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            elif seek_length < 0:
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                # we haven't read enough to check the checksum.
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                assert -8 < seek_length, "too great a seek."
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                buf = self.fileobj.read(-seek_length)
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                self.decompress.decompress(buf)
 
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                self._gzip_tail = self.decompress.unused_data + buf
 
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            else:
 
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                self._gzip_tail = self.decompress.unused_data
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            # Check the CRC and file size, and set the flag so we read
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            # a new member on the next call
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        # We then check the that the computed CRC and size of the
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        # uncompressed data matches the stored values.  Note that the size
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        # stored is the true file size mod 2**32.
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        crc32, isize = struct.unpack("<LL", self.decompress.unused_data[0:8])
 
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        assert len(self._gzip_tail) == 8, "gzip trailer is incorrect length."
 
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        crc32, isize = struct.unpack("<LL", self._gzip_tail)
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        # note that isize is unsigned - it can exceed 2GB
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        if crc32 != U32(self.crc):
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            raise IOError, "CRC check failed %d %d" % (crc32, U32(self.crc))