DEFLATE (RFC1951)/gunzip implemented in pure Lua
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bin
lmod
share/compress.deflatelua
test
CHANGES.txt
COPYRIGHT.txt
MANIFEST
README.md
dist.info
rockspec.in
util.mk

README.md

Description

compress.deflatelua is a library implementing DEFLATE, as well as zlib and gzip decompression in pure Lua.

Example usage

./gunziplua lua-5.1.4.tar.gz

Performance

It's somewhat slow (as expected). To decompress lua-5.1.4.tar.gz, it takes about 9 seconds with CRC-checking enabled (4 with LuaJIT 1.x) or 3 seconds with CRC checking disabled (2 with LuaJIT 1.x).

Rationale

Possible reasons for this module include:

  1. for pedagogical reasons
  2. to benchmark Lua
  3. to bootstrap applications like LuaRocks/LuaDist that might not have a precompiled copy of gunzip, and
  4. because DEFLATE has been implemented in other languages too, including Python, Perl, and Lisp.

Status

It should be robust and there are no known bugs. It successfully decompresses gzip files but there is currently no compressor implementation.

Dependencies

  • digest.crc32lua - CRC-32 checksum implemented in pure Lua
  • bit.numberlua - bitwise operations implemented in pure Lua as numbers (not required if using a native bitwise operation library)
  • pythonic.optparse - command-line processing resembling the Python optparse module

Conventions

The modules above follow a somewhat Perl CPAN-like naming convention. Compare to Compress::Zlib::Perl, Digest::CRC32 and the Bit:: modules.

Author

David Manura. See COPYRIGHT file.