C++ classes (RTTI)

The Mohawk engine and OS layer are polymorphic C++; the game's own logic is not (only fileSpec among its types has methods, and it has no vtable). Borland C++ emits RTTI type descriptors for each polymorphic class, and uv run classes recovers 46 of them (how). The names are the engine's own and are used exactly.

basePort                       ports: QuickDraw's GrafPort over a GDI DC (37-39 virtual methods)
 ├─ displayPort
 │   ├─ windowPort             a window's DC
 │   └─ memoryPort             an off-screen bitmap
 └─ DIBPort                    GDI into a DIB section
     └─ DIB8Port               also draws into the bits itself (8-bit blitters)
DIB                            helper around a DIB section (no vtable parent)

audioObj                       sounds (22-slot vtable; the base implements seven)
 ├─ midiObj
 ├─ waveObj
 └─ wavestreamObj              streamed from the resource's file
wavebuf                        a waveOut-like output buffer
 ├─ wavebufWO                  WaveOut, written ahead by a polling thread
 └─ wavebufDS                  a looping DirectSound buffer
wmxObject                      WaveMix
 ├─ wmxMixer                   software mixing
 └─ wmxWaveOut                 straight to waveOut

asyncAPI                       asynchronous file operations
 └─ async… (12 classes)        asyncCreateFile, asyncReadFile, asyncFindFirstFile, …

sync                           the OS layer's synchronisation objects
 ├─ event
 ├─ mutex
 └─ thread                     cooperative thread on a fiber

xmsg ─ xalloc, string::lengtherror, string::outofrange   Borland's exceptions
typeinfo, Bad_cast, Bad_typeid, string, TStringRef        Borland's runtime
fileSpec                       the game's file specifier (no vtable)

Conventions that follow from them

• A vtable is in DATA, preceded by a pointer to its class descriptor and two zero words; slot 0 is the virtual destructor. Constructors store the vtable address into the object; destructors take a hidden flags argument (bit 0: also free).
• The engine's methods are __cdecl (they don't pop their arguments) and take this as the first stack argument.
• A class that declares no destructor under a base with a virtual one gets an implicit destructor, emitted in the last module that needs the class's vtable (displayPort::~displayPort lives in windowPort's module). @zoombi32-implicit markers name them and match measures them.
• The port classes' sizes matter: DIBPort is declared under #pragma pack(push, 4) so newPort allocates 0xc8 bytes for it and 0xc6 for the derived DIB8Port.
• An object created by a global's constructor or destructor (iniState, files) is run by unnamed <startup>/<exit> functions listed in the object's _INIT_/_EXIT_ segments.