Port of the regular expression engine re2j https://github.com/google/re2j
RE2 is a regular expression engine that runs in time linear in the size of the input. RE2/CS is a port of RE2/J to C#, which is a port of the original RE2 C++ code to Java.
As with other languages, C#'s regular expression api (System.Text.RegularExpressions) uses a backtracking mechanism in matching regular expressions. This code uses Thompson's NFA algorithm, which was implemented by Cox.
This port was done in two days, the first to convert the Java into C#, and the second to get the code working with a few tests.