When using `UNPACKED_MPQS`, avoid all the SDL machinery for reading
files.
This is beneficial not only due to reduced indirection but also because
we can test for the file's existence and get the file size without
opening it, which is much faster.
https://github.com/diasurgical/devilutionx-mpq-tools produces an unpacked MPQ
with all the graphics converted to CLX and the unused files removed.
This is primarily useful on RAM-constrained platforms, such as PS2,
because it eliminates the MPQ overhead.
Adds a build option to load from such unpacked directories instead of the MPQ.
These directories are searched for in the same locations
where the MPQs would be searched for otherwise.
Example directory layout:
* /usr/local/share/diasurgical/devilutionx/diabdat/ -- unpacked and converted diabdat.mpq
* /usr/local/share/diasurgical/devilutionx/hellfire/ -- unpacked and converted hellfire MPQs (all of them merged into 1 directory)
* /usr/local/share/diasurgical/devilutionx/fonts/ -- unpacked fonts.mpq
* /usr/local/share/diasurgical/devilutionx/pl/ -- unpacked pl.mpq
These directory structure is produced by calling `unpack_and_minify_mpq`
Rather than using the Windows-like `MAX_PATH`, what we really want is 2
things:
1. Maximum path of a file in an MPQ. This is now `MaxMpqPathSize`.
2. Max size for the known monster paths. This is now 64 for sounds and
TRNs, which is more than enough (picked arbitrarily).
1. Store all key data and all values data as 2 char arrays.
2. Change map keys to char pointers.
3. Change map values to offsets into the values array.
Example savings for Russian: 460 KiB -> 374.2 KiB (-85.8 KiB)
* Map: 68.5 KiB (with `string_view` keys it would be 101.5 KiB)
* Keys array: 108.7 KiB
* Values array: 197.0 KiB
1. Do not modify the map after loading. Instead, return string views
(guaranteed to be null-terminated) from look up functions and return
the key directly if not found.
2. Use an `unorded_map` instead of `map` where available (C++20).
Saves a bit of RAM (~50 KiB) and improves lookup performance.
We ensure that selectable lines are placed at the same vertical
coordinates but space out unselectable text lines at the cost
of reduced heigh of empty space between the store items.
We also have to move the back button in scrollable lists to the
lower right.
This can definitely be improved further but at least it solves
the problem for now.
Refs #3162
libmpq is a much simpler alternative to StormLib for reading MPQ archives.
We use our own fork of libmpq: https://github.com/diasurgical/libmpq
Impact:
* DevilutionX is now a lot more portable. Unlike StormLib, libmpq only
needs platform-specific code for Windows.
* Locks around file access **removed** (instead we duplicate the file descriptor for streamed audio only).
* RAM usage is **300 KiB** lower than StormLib.
* Stripped release linux_x86_64 binary is **32 KiB** smaller.
* Amiga build now hangs instead of crashing.
`std::make_unique<T[]>(size)` always zero-initalizes the array.
C++20 has `std::make_unique_for_overwrite` to avoid that, while
older C++ versions can use the approach applied here.