README.md

Compression algorithms in C++

src/

• compress executable that can compress and extract arbitrary files with various compression methods (default: Huffman):

  •  $ build/compress -h
     Usage: build/compress [options] INPUT_FILENAME
     -h, --help
       Show this help message
     -l, --lzw
       Use LZW compression instead of Huffman
     -b, --bwmh
       Use Burrows-Wheeler, move-to-front, and then Huffman compression
       instead of only Huffman
     -x, --extract
       Extract input file instead of compressing it
    
     Examples:
     build/compress input.txt		Compress input.txt with Huffman
     build/compress -l input.txt		Compress input.txt with LZW
     build/compress -xl input.txt.lzw	Extract input.txt.lzw with LZW
    

include/

• huffman::compress and huffman::expand to apply Huffman-style lossless compression to data streams
• lzw::compress and lzw::expand to apply Lempel–Ziv–Welch (LZW) lossless compression to data streams
• BitStreamIn as a wrapper to easily read a bit stream from std::istream
• BitStreamOut as a wrapper to easily write a bit stream to std::ostream
• ShortBitSet as a simple bit set with up to 32 bits (stored in a uint32_t) and some convenience functions
• bw::encode and bw::decode for applying the Burrows-Wheeler transform (Note: not the most efficient implementation due to circular suffix array sorting)
• mtf::encode and mtf::decode for applying the Move-to-front transform

Compilation and execution

• Download submodules (for unit tests): git submodule update --init --recursive
• Compile with cmake:

  mkdir build
  cd build/
  cmake ..
  make

• Go to top-level folder again: cd ..
• Run all tests: find build/ -name "*_gtest" -exec {} \;

References

• Introduction to Algorithms by Cormen et al.
• Algorithms, Part II by Princeton University (Robert Sedgewick, Kevin Wayne)