hot patching hook

; hot patching hook
; xorc1zt

Procedure HotPatchHook(TargetFuncAddress.l, ProxyFuncAddress.l)
  ;E9 XX XX XX XX EB F9
  Protection.w
  JumpOffset.l = ( ProxyFuncAddress - ( TargetFuncAddress-5 ) )-5
  VirtualProtect_(TargetFuncAddress-5, 7, #PAGE_EXECUTE_READWRITE, @Protection)
  PokeA( TargetFuncAddress-5, $E9 ) ;Far Jump
  PokeL( TargetFuncAddress-4, JumpOffset )
  PokeA( TargetFuncAddress,   $EB ) ;Short Jump
  PokeA( TargetFuncAddress+1, $F9 ) ; -5
  VirtualProtect_(TargetFuncAddress-5, 7, Protection, @Protection )
EndProcedure

Procedure RemoveHook(TargetFuncAddress.l)
  ;90 90 90 90 90 8B FF
  Protection.w
  VirtualProtect_(TargetFuncAddress-5, 7, #PAGE_EXECUTE_READWRITE, @Protection)
  PokeA( TargetFuncAddress-5, $90 )
  PokeA( TargetFuncAddress-4, $90 )
  PokeA( TargetFuncAddress-3, $90 )
  PokeA( TargetFuncAddress-2, $90 )
  PokeA( TargetFuncAddress-1, $90 )
  PokeA( TargetFuncAddress,   $8B )
  PokeA( TargetFuncAddress+1, $FF )
  VirtualProtect_(TargetFuncAddress-5, 7, Protection, @Protection )
EndProcedure

Procedure.b IsHotPatchable(TargetFuncAddress.l)
  op.q = PeekQ(TargetFuncAddress-5)
  If FindString(Hex(op), "FF8B9090909090", 3)
    ProcedureReturn #True
  EndIf
  ProcedureReturn #False
EndProcedure