Will be used from several functions to verify the signatures for
different containers (TMDs, tickets, device signed blobs).
An option was added to disable signature checks, because that could be
useful for people trying to import unsigned stuff.
This makes it possible to catch errors earlier so that file systems
simply fail to load instead of behaving oddly. It also makes it possible
to check for errors that weren't checkable before, like the end of a
directory being after the end of the parent directory.
Instead of expecting callers to know how the size of directory file infos
relates to which files are in which directories, filesystems now offer a
GetRoot() method, and file infos offer a way to get their children. As
a bonus, m_FileInfoVector no longer has to be created and kept around
in RAM. Only the file info objects that actually are used are created.
Not initializing until the filesystem is used is good when
a filesystem is constructed and then never used, but nobody does that.
This simplifies the code a little and lets all methods be const.
Instead of using lots of small scattered reads to read the FST,
only one big read is used, which is more efficient.
This also means that the FST only allocates memory once and stores all
strings close to each other - good for the CPU cache. The file info
objects use pointers to this FST memory of containing data themselves.
Keeping around the big m_FileInfoVector containing objects with only
pointers is a bit unnecessary, but that will be fixed soon.
Instead of calling GetPathFromFSTOffset for every file info, FindFileInfo
now only looks at names in directories that are included in the path.
For the common case of searching for "opening.bnr", this means that
only root-level files and directories have to be searched through.
Some callers already have the file info, making the relatively slow
FindFileInfo calls unnecessary. Callers that didn't have the file info
will now need to call FindFileInfo on their own.
Some callers (i.e. ISOProperties) don't want the full path, so giving them
it is unnecessary. Those that do want it can use GetPathFromFSTOffset.
Not storing full paths everywhere also saves a small bit of RAM and is
necessary for a later commit. The code isn't especially pretty right now
(callers need to use FST offsets...) but it'll become better later.
GC/Wii filesystem internals shouldn't be exposed to other classes.
This change isn't especially useful by itself, but it opens up the
way for some neat stuff in the following commits.
