We can avoid constructing a std::vector here by simply passing a pointer
to the original data and the size of the copy we wish to perform to the
backend's Write() function instead, avoiding copying the data where it's
otherwise not needed.
We were using a second std::vector as a buffer to convert another
std::vector's data into a byte sequence, however we can just use
pointers to the original data and use them directly with WriteBuffer,
which avoids copying the data at all into a separate std::vector.
We simply cast the pointers to u8* (which is allowed by the standard,
given std::uint8_t is an alias for unsigned char on platforms that we
support).
Previously we were just copying the data whole-sale, even if the length
was less than the total data size. This effectively makes the
actual_data vector useless, which is likely not intended.
Instead, amend this to only copy the given length amount of data.
At the same time, we can avoid zeroing out the data before using it by
passing iterators to the constructor instead of a size.
This was introduced within 4f81bc4e1bd12e4df7410c6790ba818d8dbba9c0, and
considering there's no comment indicating that this is intentional, this
is very likely a bug.
This makes it a compilation error to construct additional instances of
the System class directly, preventing accidental wasteful constructions
over and over.
This would result in a lot of allocations and related object
construction, just to toss it all away immediately after the call.
These are definitely not intentional, and it was intended that all of
these should have been accessing the static function GetInstance()
through the name itself, not constructed instances.
These operators don't modify internal class state, so they can be made
const member functions. While we're at it, drop the unnecessary inline
keywords. Member functions that are defined in the class declaration are
already inline by default.
This provides the equivalent behavior, but without as much boilerplate.
While we're at it, explicitly default the move constructor, since we
have a move-assignment operator defined.
This doesn't actually modify the internal class state, so it can be a
const member function. While we're at it, amend the function to take
its arguments by const reference.
QString initializes to an empty string by default, so this does nothing
meaningful. While we're at it, use a constructor initializer list for
initializing the gamelist member variable.
