We have developed the CMJBitset class as a plug-in replacement for bitset. The CMJBitset classm depending on compilation optionsm may take as little as 7 bytes to represent a bitset of any size, assuming all the bits are set or reset. In comparision, a 1024 bitset will take 128 bytes. In essence, the CMJBitset operates by run length encoding a bitset if the bitset is either almost all set/reset, but otherwise uses the STL bitset class.

http://codeguru.com/Cpp/Cpp/cpp_mfc/bits/article.php/c7429/

An article by Eric Uner talks a bit about generating reandom numbers, something we all want to do from time to time.

http://www.embedded.com/showArticle.jhtml?articleID=20900500

FLAC is a port of the Free Lossless Audio Codec (FLAC) library to Java. This library allows java developers to experiment and write programs that use the FLAC algorithms.

Version 0.5 is shipping as of June, 2004.

http://jflac.sourceforge.net/

A J2EE servlet filter which compresses data written to the response. It supports several algorithms (gzip, deflate, etc.) and emphasizes minimal memory usage and high throughput. Also provides detailed performance stats.

http://sourceforge.net/projects/pjl-comp-filter/

The zisofs filesystem is an extension to the ISO9660 filesystem that allows files, on a file-by-file basis, to be stored compressed and decompressed in real time. The zisofs filesystem is supported by recent versions of Linux (2.4.14 or later). Legacy systems can still read uncompressed files. zisofs-tools contains the tools necessary to create such a compressed ISO9660 filesystem and to read compressed files on a legacy system.

http://freshmeat.net/projects/zisofs-tools/

An open source project that performs PPM compression on XML files. The advance knowledge of XML format helps give this algorithm somewhat better compressions ratios on XML data than universal compressors.

Version 0.98.1 was shipping as of June, 2004.

http://www.cs.cornell.edu/People/jcheney/xmlppm/xmlppm.html

This page describes a program, ent, which applies various tests to sequences of bytes stored in files and reports the results of those tests. The program is useful for those evaluating pseudorandom number generators for encryption and statistical sampling applications, compression algorithms, and other applications where the information density of a file is of interest

http://www.fourmilab.ch/random/

This version of file encoder and decoder program is based on the Huffman coding method. It explicitly demonstrates the details of the files during the encoding and decoding. The algorithm is encapsulated in a class En_Decode in standard C++.

http://codeproject.com/cpp/HandyHuffmanCoding.asp

An article that describes itself as showing how to implement LZW compression in MFC.

http://codeproject.com/cpp/LZWCompression.asp

Pack all your files into a single executable with MoleBox or MoleBox Pro.

http://www.molebox.com

Libarchive is a programming library that can create and read several different streaming archive formats, including most popular tar variants and the POSIX cpio format. The bsdtar program is an implementation of tar(1) that is built on top of libarchive. It started as a test harness, but is quickly moving toward becoming a candidate system tar for FreeBSD

http://people.freebsd.org/~kientzle/libarchive/

by Ziv and Lempel. The seminal LZ78 paper which spawned LZW, GIF, and an entire academic industry.

Update 2004: Document is now packed in RAR format.

http://www.compression.ru/download/articles/lz/ziv_lempel_1978_variable-rate_pdf.rar

The 1977 paper describing an algorithm for compression using pointers to previously seen text. This algorithm, later known as LZ77, is still one of the most widely used techniques for lossless data compression in use today.

Update 2004: Document is now packed in RAR format.

http://www.compression.ru/download/articles/lz/ziv_lempel_1977_universal_algorithm_pdf.rar

WavPack allows you to losslessly compress (and restore) both 16 and 24-bit audio files in the .WAV format. Unlike “lossy” compression schemes (like MP3) that discard information, WavPack converts the audio data into a more compact form so that the restored files are digitally identical to the original source. It’s somewhat like the file compression portion of WinZIP except that it’s optimized for audio data. Like other lossless compression schemes the data reduction varies with the source, but it is generally between 25% and 50% for typical popular music and somewhat better than that for classical music and other sources with greater dynamic range.

http://www.wavpack.com/

This group at Loughborough University in the UK would like to use sophisticated compression techniques in high speed networks. To make it all happen, they need to do it in hardware, and do it in parallel. This page has information about their efforts, along with links to papers and other information.

hhttp://www.lboro.ac.uk/departments/el/research/esd/projects/parallel_comp.htm

A fast ASIC core designed for lossless compression.

http://www.lboro.ac.uk/departments/el/research/esd/projects/web_xmatch/XMatchPRO_home.htm

This package includes 12Zip and 12Zip2. The first version uses Zip compatible compression, and the second uses a BWT variant.

Version 7.0 of the package is shipping as of May, 2004

http://www.12ghosts.com/ghosts/zip.htm

Marcus Geelnard has created a batch of compression routines that you can plug and ply into your programs at will. Marcus is using the wonderfully open zlib license, which means thare are just about no reason you can’t use this code. The 1.0.5 added an LZ77 codec to the RLE, Huffman, and Rice coders

Satisfied user Todd W said: I needed a simple set of compression routines for use in an embedded system. I must be able to store a fair amount of information in a small EEPROM as a generic database. The Huffman coder works very well in the application and has met my needs exactly! Very nice!

http://bcl.sourceforge.net/

Imran Akthar’s implementation of the BWT transform in Matlab. Free.

http://www.geocities.com/imran_akthar/files/bwt_matlab_code.zip