Error at the end of zipping: ushort format requires 0 <= number <= (0x7fff * 2 + 1)

[tomresan]

Hey,
I'm getting an error at the end of zipping a larger amount of files (~80.000 files, totaling ~ 1GB).

ushort format requires 0 <= number <= (0x7fff * 2 + 1)
  File ".../zipstream/zipstream.py", line 228, in _make_cdend
    cdend = consts.CD_END_STRUCT.pack(*cdend)
  File ".../zipstream/zipstream.py", line 241, in _make_end_structures
    yield self._make_cdend()
  File ".../zipstream/zipstream.py", line 306, in stream
    for chunk in self._make_end_structures():

[michalc]

(I'm not involved with this project, am just interested in zip files for some reason...)

I think that non-zip64 zip files are limited to a maximum of 2^16 - 1 = 65535 = 0xffff = 0x7fff * 2 + 1 member files, since the number of member files must be stored in an unsigned integer 2 bytes long. If you go to APPNOTE.TXT and search for "End of central directory record" you should see that "total number of entries in the central directory" is a 2 byte field.

zip64 has a much bigger limit, but looking in the README and around the code, it looks like zip64 isn't supported. Often zip64 is described as having a bigger total size limit - it does, but it also has a bigger limit on number of files that can be stored in the zip.