PhysicsFS is a library to provide abstract access to various archives. It is intended for use in video games. For security, no file writing done through the PhysicsFS API can leave a defined write directory. For file reading, a search path with archives and directories is defined, and it becomes a single, transparent hierarchical file system. So archive files can be accessed in the same way as you access files directly on a disk, and it makes it easy to ship a new archive that will override a previous archive on a per-file basis.