efficient, principled regular expression library


RE2 is a fast, safe, thread-friendly alternative to backtracking regular expression engines like those used in PCRE, Perl, and Python. It is a C++ library.

RE2 uses automata theory to guarantee that regular expression searches run in time linear in the size of the input. RE2 implements memory limits, so that searches can be constrained to a fixed amount of memory. RE2 is engineered to use a small fixed C++ stack footprint no matter what inputs or regular expressions it must process; thus RE2 is useful in multithreaded environments where thread stacks cannot grow arbitrarily large.

On large inputs, RE2 is often much faster than backtracking engines; its use of automata theory lets it apply optimizations that the others cannot.

Upload more screenshots

Please help extend the collection of screenshots. Just make a screenshot and upload it here. You don't need to register or anything.

Upload a screenshot

Hint: upload an image here from your clipboard with Ctrl-V


Install this software package

If the package is available for the distribution you are currently using on your computer then install the software by clicking on…

Install libre2-9