Вызов 16-разрядного кода из 32-разрядного

{ GetFeeSystemResources routine for 32-bit Delphi.

Works only under Windows 9x }


unit SysRes32;

interface

const
//Constants whitch specifies the type of resource to be checked


GFSR_SYSTEMRESOURCES = $0000;
GFSR_GDIRESOURCES    = $0001;
GFSR_USERRESOURCES   = $0002;

// 32-bit function exported from this unit

function GetFeeSystemResources(SysResource: Word):Word;

implementation

uses

SysUtils, Windows;

type

//Procedural variable for testing for a nil

TGetFSR = function(ResType: Word): Word; stdcall;

//Declare our class exeptions

EThunkError = class(Exception);
EFOpenError = class(Exception);

var

User16Handle : THandle = 0;
GetFSR       : TGetFSR = nil;

//Prototypes for some undocumented API


function LoadLibrary16(LibFileName: PAnsiChar): THandle; stdcall;
external kernel32 index 35;


function FreeLibrary16(LibModule: THandle): THandle; stdcall;
external kernel32 index 36;


function GetProcAddress16(Module: THandle; ProcName: LPCSTR): TFarProc;stdcall;
external kernel32 index 37;


procedure QT_Thunk; cdecl;
external 'kernel32.dll' name 'QT_Thunk';


{$StackFrames On}

function GetFeeSystemResources(SysResource: Word):Word;
var

EatStackSpace: String[$3C];
begin
// Ensure buffer isn't optimised away

EatStackSpace := '';
@GetFSR:=GetProcAddress16(User16Handle,'GETFREESYSTEMRESOURCES');
if  Assigned(GetFSR) then  //Test result for nil
asm
//Manually push onto the stack type of resource to be checked first

push  SysResource
//Load routine address into EDX

mov   edx, [GetFSR]
//Call routine

call  QT_Thunk
//Assign result to the function

mov   @Result, ax
end
else raise EFOpenError.Create('GetProcAddress16 failed!');
end;

initialization

//Check Platform for Windows 9x
if Win32Platform <> VER_PLATFORM_WIN32_WINDOWS then

raise EThunkError.Create('Flat thunks only supported under Windows 9x');

//Load 16-bit DLL (USER.EXE)
User16Handle:= LoadLibrary16(PChar('User.exe'));

if User16Handle < 32 then
raise EFOpenError.Create('LoadLibrary16 failed!');

finalization

//Release 16-bit DLL when done
if User16Handle <> 0 then

FreeLibrary16(User16Handle);

end.