Abstract: Disclosed herein are systems, methods, and computer-readable storage media for matching a regular expression in an input string. A system configured to practice the method first identifies a number of substrings (k) in a regular expression of length (m). The system receives a stream of start states for each of the substrings generated according to a regular expression matching process and receives a stream of end occurrences generated according to a multi-string matching process. The system identifies all instances where an end occurrence of a particular substring matches a positive start state of the particular substring, and enters the instances as positive substring accept states in the regular expression matching process on the input string. In one aspect, the system is much more efficient when (k) is much less than (m). The system can match the regular expression based on a bit offset between the first and second stream.