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  1. Commons Compress
  2. COMPRESS-474

xlsx zip64 compatibility

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    Details

    • Type: Bug
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 1.19
    • Fix Version/s: None
    • Component/s: Archivers
    • Labels:

      Description

      Excel's xlsx files are generally zip archives. But Excel has a very specific and strict ZIP64 implementation.

      Connected Apache POI issue: [https://bz.apache.org/bugzilla/show_bug.cgi?id=57342
      ]My blog post with all the details: https://rzymek.github.io/post/excel-zip64/

      My observations on Excel requirements:

      1. If file size is > 4gb, then zip spec version 4.5 must be set in Local Header File
      2. In streaming creation the zero file sizes must be in 32 field, not in LHF's ZIP64 extra field data.
      3. ZIP64 extra field in Central Directory must not include relativeHeaderOffset. Only size or size and compressed size
      4. ZIP64 Central Directory is not supported

      I did verify these in a prototype repository at https://github.com/rzymek/commons-compress/pull/1/files. This is just a playground where I've tested the changes to verify that Excel opens the generated file.

      Test project: https://github.com/rzymek/xlsx-compress64-test

       

       

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            • Assignee:
              Unassigned
              Reporter:
              rzymek Krzysztof Rzymkowski
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              Dates

              • Created:
                Updated: