BitMagic is C++ library designed and developed to implement efficient platform independent bitsets, with the following key features:

• Several types of on-the-fly adaptive compression.
• Dynamic range of addressable space of 232 bits.
• Efficient memory management.
• Serialization in platform independent, compact format suitable for storing in files and databases.
• Performance tuning for 32-bit and 64-bit systems.

Version 3.1.4 shipped August, 2003.

http://bmagic.sourceforge.net/