Physfs

PhysicsFS is a library to provide abstract access to various archives. It is
intended for use in video games, and the design was somewhat inspired by Quake
3's file subsystem. The programmer defines a "write directory" on the physical
filesystem. No file writing done through the PhysicsFS API can leave that write
directory, for security. For example, an embedded scripting language cannot
write outside of this path if it uses PhysFS for all of its I/O, which means
that untrusted scripts can run more safely. Symbolic links can be disabled as
well, for added safety. For file reading, the programmer lists directories and
archives that form a "search path". Once the search path is defined, it becomes
a single, transparent hierarchical filesystem. This makes for easy access to ZIP
files in the same way as you access a file directly on the disk, and it makes it
easy to ship a new archive that will override a previous archive on a per-file
basis. Finally, PhysicsFS gives you platform-abstracted means to determine if
CD-ROMs are available, the user's home directory, where in the real filesystem
your program is running, etc.