[COMPRESS-487] PKWARE DCL Implode support (ZIP compression method 10)

• Type: New Feature
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Component/s: Archivers, Compressors
• Labels: zip
• Assignee: Emmanuel Bourg
• Reporter: Emmanuel Bourg
• Created: 23/May/19 14:00
• Updated: 07/May/20 21:21

Description

Commons Compress doesn't yet support the implode compression algorithm implemented in the PKWARE Data Compression Library (DCL). This algorithm can be used in ZIP files (using the compression method 10, which differs from the other implode compression method 6 already supported). It's also used in some old file formats like dBASE/xBase and game files from the 90's (.mpq).

ZIP files using this compression method can be created with recent versions of the PKWARE ZIP Compression Utility. The syntax looks like this:

pkzipc -add -dclimplode=ascii,4096 test.zip *.txt

The format is documented here:
https://groups.google.com/forum/#!msg/comp.compression/M5P064or93o/W1ca1-ad6kgJ

and here is the implementation in zlib:
https://github.com/madler/zlib/blob/master/contrib/blast/blast.c