An FPGA-based text search engine for approximate regular expression matching

Text search is a procedure to find occurrences of a pattern in a given text where the pattern and each occurrence may have a limited number of differences. Text search is an indispensable technique for bibliographic databases. In this paper, a restricted class of regular expressions is used as patterns, and all substrings in a text that are close to a pattern, possibly with some errors, are located. We call this text search problem approximate regular expression matching. For this problem, a one-dimensional systolic algorithm is presented based on dynamic programming. Experiments show that the proposed hardware engine implemented on FPGA realizes high-speed text search.