This is my implementation of Ken Thompson's regular expressions engine, discussed in his 1968 CACM paper.
git clone https://github.com/eddsanity/Fast-Regex-Engine.git
cd Fast-Regex-Engine
Note that main.c isn't part of the repository, you have to provide this yourself. (Assuming you'll be using the regex engine in main.c)
gcc main.c src/*.c -Iinclude/ -o RE.exe
cd tests/
gcc test.c ../src/*.c -I../include/ -o test.exe
Console will write on screen unit tests and overall testing result.
Code is heavily commented.