A C++ library implementing bitmap indexes with a form of word-alignment akin to the Word-Aligned Hybrid encoding (WAH) designed by Wu et al. and made available in the FastBit library.

In its current format, this library indexes efficiently flat files. It can scale up to one hundred million attribute values, and to billions of lines. Support for projection indexes is also available.

It should build without a problem on MacOS and Linux.

See doc/index.html for the documentation.

Reference:

Owen Kaser, Daniel Lemire, Kamel Aouiche, Histogram-Aware Sorting for Enhanced Word-Aligned Compression in Bitmap Indexes, DOLAP 2008, 2008. http://arxiv.org/abs/0808.2083