SANKit
Read and write PGN format and test moves for legality.
SAN Kit was made public in 1993 by Stephen Edwards, the inventor of PGN Chess notation. The original code is in C, and with few comments quite cryptic. In addition, the original author's style was quite quixotic, making it even more difficult to read.
This code is now reformatted to modern standards, adds support for NAG codes and comments, and has a "non-CLI" mode for inclusion in chess playing programs.
The code has gone through extensive analysis using the llvm/clang compiler...