"""identify_d3d_vtable.py <pid> <candidate_va>
Read consecutive DWORDs from a candidate vtable address and report how
many of them are valid d3d9.dll function pointers.
IDirect3DDevice9 has 119 slots, IDirect3DTexture9 ~17, IDirect3D9 ~16.
"""
import ctypes, ctypes.wintypes as wt, sys, struct

PROCESS_VM_READ = 0x10
PROCESS_QUERY_INFORMATION = 0x400
k = ctypes.windll.kernel32
k.OpenProcess.argtypes = [wt.DWORD, wt.BOOL, wt.DWORD]; k.OpenProcess.restype = wt.HANDLE
k.ReadProcessMemory.argtypes = [wt.HANDLE, wt.LPCVOID, wt.LPVOID, ctypes.c_size_t, ctypes.POINTER(ctypes.c_size_t)]

D3D9_BASE = 0x6F4E0000
D3D9_END  = 0x6F4E0000 + 0x17A000

def rd(h, va, n):
    buf = (ctypes.c_ubyte * n)(); sz = ctypes.c_size_t(0)
    if not k.ReadProcessMemory(h, va, buf, n, ctypes.byref(sz)): return None
    return bytes(buf[:sz.value])

pid = int(sys.argv[1])
va = int(sys.argv[2], 0)

h = k.OpenProcess(PROCESS_VM_READ | PROCESS_QUERY_INFORMATION, False, pid)
if not h: print("OpenProcess fail"); sys.exit(2)

data = rd(h, va, 4 * 130)
if not data: print(f"unreadable at 0x{va:08x}"); sys.exit(3)

# Count consecutive valid d3d9 function pointers
slot_count = 0
slots = []
for i in range(130):
    if i*4 + 4 > len(data): break
    p = struct.unpack_from('<I', data, i*4)[0]
    if D3D9_BASE <= p < D3D9_END:
        slot_count = i + 1  # at least up to here, all valid
        slots.append(p)
    else:
        # First non-d3d9 entry
        slots.append(p)
        if i > 3:
            break

print(f"Vtable @ 0x{va:08x}:  valid d3d9 slots = {slot_count}")
print(f"  Slot 0:  0x{slots[0]:08x}")
if slot_count > 2:  print(f"  Slot 2:  0x{slots[2]:08x}  (would be IUnknown::Release)")
if slot_count > 16: print(f"  Slot 16: 0x{slots[16]:08x}  (could be IDirect3D9::CreateDevice if D3D9 vtable, or IDirect3DDevice9::Reset)")
if slot_count > 23: print(f"  Slot 23: 0x{slots[23]:08x}  (would be IDirect3DDevice9::CreateTexture)")
if slot_count > 28: print(f"  Slot 28: 0x{slots[28]:08x}  (would be IDirect3DDevice9::CreateRenderTarget)")

# Identify
if slot_count >= 119:
    print(f"\n*** LIKELY IDirect3DDevice9 (119 slots expected) ***")
elif 14 <= slot_count <= 20:
    print(f"\nLIKELY IDirect3D9 or IDirect3DTexture9 (small)")
elif 4 <= slot_count <= 10:
    print(f"\nLIKELY IUnknown derivative (very small)")
else:
    print(f"\nUnknown — {slot_count} slots")

k.CloseHandle(h)