Boost.Filesystem
God no
, this is so not meant for games and will just be confuzling to fit in that role.
The games centric filesystem that is greatly portable, based on dooms filesystems, easy to use(everything is UTF-8, the end), safe for malicious scripts(there is NO way to go outside of your games root folder and read or write to rest of the system using it, so after cutting out all fstreams and FILEs, engine is sanitized and no script can be danger to outside world) and makes underlying filesystem completely transparent(no wchar_t on windows nonsense) after initializing is: PhysicsFS. Oh, and it turns zips, 7zips and few 90s games archives(id techs paks, build engine grps etc.) into part of its virtual filesystem tree and makes it so that later added folders and archives will cover up files with same paths from earlier ones so modding, changing, default and user settings etc. are very easy to achieve.