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The ZIP file format is a standard container format developed by MiniWikipediaLogoIcon.pngPKWARE and allowing a large number of compression methods. This is an open and widely used standard; however it is very seldom implemented fully.

The standard defines the following compression methods (bolded methods are supported by 3DGE):

 0 - The file is stored (no compression)
 1 - The file is Shrunk
 2 - The file is Reduced with compression factor 1
 3 - The file is Reduced with compression factor 2
 4 - The file is Reduced with compression factor 3
 5 - The file is Reduced with compression factor 4
 6 - The file is Imploded
 8 - The file is Deflated
 9 - Enhanced Deflating using Deflate64(tm)
10 - PKWARE Data Compression Library Imploding (old IBM TERSE)
12 - File is compressed using BZIP2 algorithm
14 - LZMA (EFS)
18 - File is compressed using IBM TERSE (new)
19 - IBM LZ77 z Architecture (PFS)
97 - WavPack compressed data
98 - PPMd version I, Rev 1 (as of Template:Latest, only PPMd version H is supported (.7z/.pk7, not .zip/.pk3))

Each file in a ZIP archive can be compressed with a different method. In practice, ZIP implementation is generally limited to only formats 0 (stored) and 8 (deflated).

3DGE and zipdir both support methods 0 (stored), 1 (shrunk), 6 (imploded), 8 (deflated), 12 (bzipped 2) and 14 (LZMA, also used by the 7z format). As of 2009, when Template:Forum, all the zip files on the Idgames archive can be opened successfully by 3DGE (unsupported methods are not used).

The implementation in 3DGE is supported via the use of Physics_FS, by Ryan C. Gordon.

See also

External links