A Practical Implementation of Compressed Suffix Arrays with Applications to Self-Indexing

In this paper we develop a simple and practical text indexing scheme for compressed suffix arrays (CSA). For a text of n characters, our CSA can be constructed in linear time and needs 2nH
_k
+ n + o(n) bits of space for any k ≤ clog
_σ
n - 1 and any constant c <; 1, where H
_k
denotes the kth order entropy. We compare the performance of our method with two established compressed indexing methods, the FM-index and the Sad-CSA. Experiments on the Canterbury Corpus and the Pizza&Chili Corpus show significant advantages of our algorithm over two other indexes in terms of compression and query time. Our storage scheme achieves better performance on all types of data present in these two corpora, except for evenly distributed data, such as DNA. The source code for our CSA is available online.