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  1. Commons Compress
  2. COMPRESS-115

Imploded entry decompression for Zip archives (method 6)

    Details

    • Type: New Feature
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 1.0
    • Fix Version/s: 1.7
    • Component/s: Archivers
    • Labels:

      Description

      This is a RFE to implement the decompression of zip file entries using the imploded compression method (aka method 6). This method is found in archives created with old versions of PKZip. Only the decompression operation is really useful since this method is less efficient than deflate.

      Some links with technical information about this format:

      http://www.pkware.com/documents/casestudies/APPNOTE.TXT

      http://en.wikipedia.org/wiki/Shannon%E2%80%93Fano_coding

      http://en.wikipedia.org/wiki/LZ77

      http://src.opensolaris.org/source/xref/sfw/usr/src/cmd/unzip/explode.c

      1. explode.c
        24 kB
        Emmanuel Bourg
      2. imploding-4Kdict-2trees.zip
        0.7 kB
        Emmanuel Bourg
      3. imploding-8Kdict-3trees.zip
        4 kB
        Emmanuel Bourg

        Issue Links

          Activity

          Show
          ebourg Emmanuel Bourg added a comment - - edited Alternative explode implementation in ClamAV: https://github.com/vrtadmin/clamav-devel/blob/master/libclamav/explode.h https://github.com/vrtadmin/clamav-devel/blob/master/libclamav/explode.c
          Hide
          ebourg Emmanuel Bourg added a comment -

          Here are 2 test files covering the variants of the imploded format (4K or 8K sliding dictionary, 2 or 3 Shannon-Fano trees)

          Show
          ebourg Emmanuel Bourg added a comment - Here are 2 test files covering the variants of the imploded format (4K or 8K sliding dictionary, 2 or 3 Shannon-Fano trees)

            People

            • Assignee:
              ebourg Emmanuel Bourg
              Reporter:
              ebourg Emmanuel Bourg
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              Dates

              • Created:
                Updated:
                Resolved:

                Development