Token stitcher for a content search system having pipelined engines

Abstract

A content search system includes multiple pipelined search engines that implement different portions of a regular expression search operation. For some embodiments, the search pipeline includes a DFA engine, an NFA engine, and a token stitcher that combines partial match results generated by the DFA and NFA engines. The token stitcher can be configured to implement unbounded sub-expressions without utilizing resources of the DFA or NFA engines. A token stitcher may comprise an input line for receiving tokens that indicate a partial match between an input string and a regular expression, a flag bank that stores flags which, when activated, identify one or more of the sub-expressions that match the input string, a program memory that stores programs that each comprises instructions for processing tokens, and an engine configured to identify programs that are associated with a newly received token.