#534 ZIP fails on achives containing > 65.535 entries

open
nobody
7
2007-10-08
2007-10-04
dgiesy2
No

ZIP UNZIP
and
ZIP LIST
behave unpredictably when the Zip archive contains greater than 65,535 entries.
A partial listing of the contests is returned with no indication that there are additional files.

Ideally ZIP needs to support large archives.
Minimally if it can't read an entire archive it should return an error rather than a partial listing.

Discussion

  • Sharon Lucas

    Sharon Lucas - 2007-10-05

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    In the prebuild.zip file that has 65,588 entries, it's "End of central directory" record has a 2-byte field that contains the total number of entries in the central directory and it is set to 51, and so the ZIP service reads this and only lists the first 51 entries in the file.

    The PKWare ZIP File Format Specification says you can have a "Zip64 end of central directory record" which has a 8-byte field for the "total number of entries in the central directory" but it does not appear that prebuild.zip contains this "Zip64 end of central directory record".

    So, at this point, I don't know how a tool like the ZIP service is supposed to get the number of entries, or how other ZIP tools can successfully list > 64K entries in a zip file. Perhaps they just iterating through the file headers and not depending on a field that provides the total number of entries? I don't know.

     
  • Sharon Lucas

    Sharon Lucas - 2007-10-08

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    user_id=285070
    Originator: NO

    Changing to a feature request as this request is to add support to the ZIP service to read/use the "Zip64 end of central directory record" if provided in a zipfile.

     
  • Sharon Lucas

    Sharon Lucas - 2007-10-08
    • labels: 617624 --> Service::Zip
    • milestone: 145350 -->
     
  • Sharon Lucas

    Sharon Lucas - 2007-10-08
    • priority: 5 --> 7
     

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