Еще раз об отображаемом в память файле

unit
 MapWForm;

interface


uses

  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, SyncObjs, TeEngine, Series, ExtCtrls, TeeProcs, Chart, Grids,
  ComCtrls;

type

  TForm1 = class
(TForm)
    Timer1: TTimer;
    TrackBar1: TTrackBar;
    Label1: TLabel;
    procedure
 FormCreate(Sender: TObject);
    procedure
 FormDestroy(Sender: TObject);
    procedure
 Timer1Timer(Sender: TObject);
    procedure
 TrackBar1Change(Sender: TObject);
  private

    hMapFile: THandle;
    MapFilePointer: Pointer;
  end
;

var

  Form1: TForm1;

implementation


{$R *.DFM}

procedure
 TForm1.FormCreate(Sender: TObject);
begin

  hMapFile := CreateFileMapping(
    $FFFFFFFF, // file handle ... or memory
    nil
, // security
    Page_ReadWrite, // access rights
    0, // high memory size
    10000, // low memory size
    'DdhMappedFileGraph'); // mapped file name
  if
 hMapFile <> 0 then

    MapFilePointer := MapViewOfFile(
      hMapFile, // handle returned above
      File_Map_All_Access, // access rights
      0, 0, 0) // access the entire mapped file
  else

    ShowMessage('hMapFile = 0');
  if
 MapFilePointer = nil
 then

    ShowMessage('MapFilePointer = nil');
  // not a listener of messages...
  TrackBar1.Position := 1 + Random(10);
  Label1.Caption := IntToStr(TrackBar1.Position)
end
;

procedure
 TForm1.FormDestroy(Sender: TObject);
begin

  UnMapViewOfFile(MapFilePointer);
  CloseHandle(hMapFile);
end
;

procedure
 TForm1.Timer1Timer(Sender: TObject);
var

  X, Y: Integer;
  Address: Pointer;
begin

  X := TrackBar1.Position - 1;
  Y := Random(10);
  Address := pChar(MapFilePointer) + (X + Y * 10) * 4;
  PInteger(Address)^ := PInteger(Address)^ + Random(10);
  Address := pChar(MapFilePointer) + 400;
  while
 PInteger(Address)^ <> 0 do

  begin

    PostMessage(PInteger(Address)^, wm_user, 0, 0);
    Address := pChar(Address) + 4;
  end
;
end
;

procedure
 TForm1.TrackBar1Change(Sender: TObject);
begin

  Label1.Caption := IntToStr(TrackBar1.Position)
end
;

initialization

  Randomize;
end
.

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