Have you noticed how some compressors like winrar ® or winzip ® can create self-extracting files. Today we will see how we can generate these files using the ZLib unit wich is included with delphi.

The logic goes like this

1) Create a exe which the capacity of decompress a resource, this project is responsible for extract the compressed data, which was previously stored as a resource inside of self.

This is the code to extract the data stored inside of the resource

procedure Extract;
var
  DeCompressStream : TDeCompressionStream;
  ResourceStream   : TResourceStream;
  DestFileStream   : TFileStream;
  FileNameDest     : String;
  RecSFX           : TRecSFX;
begin

  if FindResource(0, 'SFXDATA', RT_RCDATA)=0 then //find the compressed data
  begin
    Application.MessageBox('Sorry i am empty','Warning',MB_OK+MB_ICONWARNING);
    Exit;
  end
  else
  if FindResource(0, 'SFXREC', RT_RCDATA)=0 then //find the header data
  begin
    Application.MessageBox('Sorry i dont have header data','Warning',MB_OK+MB_ICONWARNING);
    Exit;
  end;

 try
    ResourceStream:= TResourceStream.Create(0,'SFXREC',RT_RCDATA); //read the header stored in the resorce named SFXREC
    try
        ResourceStream.Position:=0;
        Move(ResourceStream.Memory^,RecSFX,SizeOf(RecSFX));
        ProgressBarSfx.Max:=RecSFX.Size;
    finally
      ResourceStream.Free;
    end;

    ResourceStream:= TResourceStream.Create(0,'SFXDATA',RT_RCDATA); //read the compressed data stores in the SFXDATA resource
    try
      ProgressBarSfx.Max:=ResourceStream.Size;
      FileNameDest   := EditPath.Text+ChangeFileExt(ExtractFileName(ParamStr(0)),'');
      DestFileStream := TFileStream.Create(FileNameDest,fmCreate); //create the file to uncompress the data
      try
        DeCompressStream:=TDeCompressionStream.Create(ResourceStream);
        DeCompressStream.OnProgress:=DoProgress; //assign the OnProgress event to see the progress
        try
           DestFileStream.CopyFrom(DeCompressStream,RecSFX.Size); //decompress the data
        finally
          DeCompressStream.Free;
        end;
      finally
        DestFileStream.Free;
      end;
    finally
      ResourceStream.Free;
    end;
 except on e : exception do
   Application.MessageBox(PAnsiChar(e.Message),'Error',MB_OK+MB_ICONERROR);
 end;
end;

2) Transform this project in a resource and attach this resource to the second project, using the BRCC32.exe tool

create a file called Stub.rc with this content

STUB RT_RCDATA "SfxExtractor.exe"

now compile the rc file

BRCC32.exe Stub.rc

3) include the generated Stub.res file in the second project

{$R Stub.res}

4) Now the second project select a file to compress

5) Extract the STUB resource and then create a new exe file

var
  StubStream: TResourceStream;
begin
  StubStream := TResourceStream.Create( HInstance, 'STUB', 'RT_RCDATA');
  try
     DeleteFile(FSfxFileName);
     StubStream.SaveToFile(FSfxFileName);
  finally
    StubStream.Free;
  end;
  Result:=FileExists(FSfxFileName);
end;

6) Compress the selected file using the TCompressionStream class and add two resources to the New STUB exe,
one resource store the header info (Original filename, size) and the another store the compressed data.

check the code wich compress the data in a resource and create the two resources in the STUB exe.

procedure CreateSFX;
var
  SrcFileStream   : TFileStream;
  CompressedStream: TMemoryStream;
  hDestRes        : THANDLE;
  Compressor      : TCompressionStream;
  RecSFX          : TRecSFX;
begin
  SrcFileStream      := TFileStream.Create(FSrcFileName,fmOpenRead or fmShareDenyNone); //open the file to compress
  ProgressBarSfx.Max := SrcFileStream.Size;
 try
  try
    CompressedStream:= TMemoryStream.Create;
    try
      Compressor:=TCompressionStream.Create(GetCompressionLevel,CompressedStream); //create the stream to compress the data
      try
        Compressor.OnProgress:=DoProgress;
        Compressor.CopyFrom(SrcFileStream,0);
      finally
        Compressor.Free;
      end;
        //Write the header
        FillChar(RecSFX,SizeOf(RecSFX),#0);
        RecSFX.Size:=SrcFileStream.Size;
        Move(ExtractFileName(FSrcFileName)[1],RecSFX.Name,Length(ExtractFileName(FSrcFileName)));

        hDestRes:= BeginUpdateResource(PAnsiChar(FSfxFileName), False);
        if hDestRes <> 0 then
          if UpdateResource(hDestRes, RT_RCDATA,'SFXREC',0,@RecSFX,SizeOf(RecSFX)) then //create the resource in the exe with the header info
             if EndUpdateResource(hDestRes,FALSE) then
             else
             RaiseLastOSError
          else
          RaiseLastOSError
        else
        RaiseLastOSError;

        hDestRes:= BeginUpdateResource(PAnsiChar(FSfxFileName), False);
        if hDestRes <> 0 then
          if UpdateResource(hDestRes, RT_RCDATA,'SFXDATA',0,CompressedStream.Memory,CompressedStream.Size) then //create the resource in the exe with the compressed data
            if EndUpdateResource(hDestRes,FALSE) then //if all is ok show the summary info
            begin
               LabelInfo.Caption:=
               Format('SFX Created %sOriginal Size %s %sCompressed Size %s Ratio %n %%',[#13,FormatFloat('#,',SrcFileStream.Size),#13,FormatFloat('#,',CompressedStream.Size),CompressedStream.Size*100/SrcFileStream.Size]);
               ProgressBarSfx.Position:=ProgressBarSfx.Max;
               ButtonCreateSFX.Enabled:=False;
            end
            else
            RaiseLastOSError
          else
          RaiseLastOSError
        else
        RaiseLastOSError;
    finally
      CompressedStream.Free;
    end;
  finally
    SrcFileStream.Free;
  end;
 except on e : exception do
   Application.MessageBox(PAnsiChar(e.Message),'Error',MB_OK+MB_ICONERROR);
 end;
end;

You can add many features like password, checksum validation, encryption and others to the STUB Application. just keep in mind final file size of the STUB.

Finally when you run the second application (Project CreateSFX) and select a file the aplication will create a SFX file.

Project SfxExtractor

{$SetPEFlags 1}  //  remove relocation table

unit MainSFX;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ComCtrls;

type
  TFrmMain = class(TForm)
    ButtonSelDir: TButton;
    EditPath: TEdit;
    ButtonExtract: TButton;
    ProgressBarSfx: TProgressBar;
    Label1: TLabel;
    procedure ButtonSelDirClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure ButtonExtractClick(Sender: TObject);
  private
    procedure Extract;
    procedure DoProgress(Sender: TObject);
  public
  end;

var
  FrmMain: TFrmMain;

implementation
{$R *.dfm}

uses
ShlObj,
ZLib,
Common;

function SelectFolderCallbackProc(hwnd: HWND; uMsg: UINT; lParam: LPARAM; lpData: LPARAM): Integer; stdcall;
begin
  if (uMsg = BFFM_INITIALIZED) then
    SendMessage(hwnd, BFFM_SETSELECTION, 1, lpData);
  Result := 0;
end;

function SelectFolder(hwndOwner: HWND;const Caption: string; var InitFolder: string): Boolean;
var
  ItemIDList: PItemIDList;
  idlRoot   : PItemIDList;
  Path      : PAnsiChar;
  BrowseInfo: TBrowseInfo;
begin
  Result := False;
  Path := StrAlloc(MAX_PATH);
  SHGetSpecialFolderLocation(hwndOwner, CSIDL_DRIVES, idlRoot);
  with BrowseInfo do
  begin
    hwndOwner := GetActiveWindow;
    pidlRoot  := idlRoot;
    SHGetSpecialFolderLocation(hwndOwner, CSIDL_DRIVES, idlRoot);
    pszDisplayName := StrAlloc(MAX_PATH);
    lpszTitle := PAnsiChar(Caption);
    lpfn      := @SelectFolderCallbackProc;
    lParam    := LongInt(PAnsiChar(InitFolder));
    ulFlags   := BIF_RETURNONLYFSDIRS OR BIF_USENEWUI;
  end;

  ItemIDList := SHBrowseForFolder(BrowseInfo);
  if (ItemIDList <> nil) then
    if SHGetPathFromIDList(ItemIDList, Path) then
    begin
      InitFolder := Path;
      Result    := True;
    end;
end;

procedure TFrmMain.Extract;
var
  DeCompressStream : TDeCompressionStream;
  ResourceStream   : TResourceStream;
  DestFileStream   : TFileStream;
  FileNameDest     : String;
  RecSFX           : TRecSFX;
begin

  if FindResource(0, 'SFXDATA', RT_RCDATA)=0 then
  begin
    Application.MessageBox('Sorry i am empty','Warning',MB_OK+MB_ICONWARNING);
    Exit;
  end
  else
  if FindResource(0, 'SFXREC', RT_RCDATA)=0 then
  begin
    Application.MessageBox('Sorry i dont have header data','Warning',MB_OK+MB_ICONWARNING);
    Exit;
  end;

 try
    ResourceStream:= TResourceStream.Create(0,'SFXREC',RT_RCDATA);
    try
        ResourceStream.Position:=0;
        Move(ResourceStream.Memory^,RecSFX,SizeOf(RecSFX));
        ProgressBarSfx.Max:=RecSFX.Size;
    finally
      ResourceStream.Free;
    end;

    ResourceStream:= TResourceStream.Create(0,'SFXDATA',RT_RCDATA);
    try
      ProgressBarSfx.Max:=ResourceStream.Size;
      FileNameDest   := EditPath.Text+ChangeFileExt(ExtractFileName(ParamStr(0)),'');
      DestFileStream := TFileStream.Create(FileNameDest,fmCreate);
      try
        DeCompressStream:=TDeCompressionStream.Create(ResourceStream);
        DeCompressStream.OnProgress:=DoProgress;
        try
           DestFileStream.CopyFrom(DeCompressStream,RecSFX.Size);
        finally
          DeCompressStream.Free;
        end;
      finally
        DestFileStream.Free;
      end;
    finally
      ResourceStream.Free;
    end;
 except on e : exception do
   Application.MessageBox(PAnsiChar(e.Message),'Error',MB_OK+MB_ICONERROR);
 end;
end;

procedure TFrmMain.ButtonExtractClick(Sender: TObject);
begin
  Extract;
end;

procedure TFrmMain.ButtonSelDirClick(Sender: TObject);
var
  Path: String;
begin
  Path:=EditPath.Text;
   if SelectFolder(Handle,'Select the output directory',Path) then
    EditPath.Text:=IncludeTrailingPathDelimiter(Path);
end;

procedure TFrmMain.DoProgress(Sender: TObject);
begin
   ProgressBarSfx.Position:=TCustomZLibStream(Sender).Position;
end;

procedure TFrmMain.FormCreate(Sender: TObject);
begin
  EditPath.Text:=IncludeTrailingPathDelimiter(ExtractFilePath(ParamStr(0)));
end;

end.

Project CreateSFX

unit MainCreateSFX;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ComCtrls, ExtCtrls, ZLib;

type
  TFrmCreateSFX = class(TForm)
    ButtonCreateSFX: TButton;
    OpenDialog1: TOpenDialog;
    EditFile: TEdit;
    ButtonSelect: TButton;
    ProgressBarSfx: TProgressBar;
    LabelInfo: TLabel;
    Label1: TLabel;
    RadioButton1: TRadioButton;
    RadioButton2: TRadioButton;
    RadioButton3: TRadioButton;
    RadioButton4: TRadioButton;
    procedure ButtonCreateSFXClick(Sender: TObject);
    procedure ButtonSelectClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    FSrcFileName   : string;
    FSfxFileName   : string;
    function  CreateStub:Boolean;
    function  GetCompressionLevel: TCompressionLevel;
    procedure CreateSFX;
    procedure DoProgress(Sender: TObject);
  end;

var
  FrmCreateSFX: TFrmCreateSFX;

implementation

uses Common;

{$R *.dfm}
{$R Stub.res}

procedure TFrmCreateSFX.ButtonCreateSFXClick(Sender: TObject);
begin
  if CreateStub then
   CreateSFX;
end;

procedure TFrmCreateSFX.ButtonSelectClick(Sender: TObject);
begin
   if OpenDialog1.Execute(Handle) then
   begin
     EditFile.Text:=OpenDialog1.FileName;
     FSrcFileName:=OpenDialog1.FileName;
     FSfxFileName:=ExtractFilePath(ParamStr(0))+ExtractFileName(EditFile.Text)+'.exe';
     ButtonCreateSFX.Enabled:=True;
     ButtonSelect.Enabled:=False;
   end;
end;

procedure TFrmCreateSFX.CreateSFX;
var
  SrcFileStream   : TFileStream;
  CompressedStream: TMemoryStream;
  hDestRes        : THANDLE;
  Compressor      : TCompressionStream;
  RecSFX          : TRecSFX;
begin
  SrcFileStream      := TFileStream.Create(FSrcFileName,fmOpenRead or fmShareDenyNone);
  ProgressBarSfx.Max := SrcFileStream.Size;
 try
  try
    CompressedStream:= TMemoryStream.Create;
    try
      Compressor:=TCompressionStream.Create(GetCompressionLevel,CompressedStream);
      try
        Compressor.OnProgress:=DoProgress;
        Compressor.CopyFrom(SrcFileStream,0);
      finally
        Compressor.Free;
      end;

        FillChar(RecSFX,SizeOf(RecSFX),#0);
        RecSFX.Size:=SrcFileStream.Size;
        Move(ExtractFileName(FSrcFileName)[1],RecSFX.Name,Length(ExtractFileName(FSrcFileName)));

        hDestRes:= BeginUpdateResource(PAnsiChar(FSfxFileName), False);
        if hDestRes <> 0 then
          if UpdateResource(hDestRes, RT_RCDATA,'SFXREC',0,@RecSFX,SizeOf(RecSFX)) then
             if EndUpdateResource(hDestRes,FALSE) then
             else
             RaiseLastOSError
          else
          RaiseLastOSError
        else
        RaiseLastOSError;

        hDestRes:= BeginUpdateResource(PAnsiChar(FSfxFileName), False);
        if hDestRes <> 0 then
          if UpdateResource(hDestRes, RT_RCDATA,'SFXDATA',0,CompressedStream.Memory,CompressedStream.Size) then
            if EndUpdateResource(hDestRes,FALSE) then
            begin
               LabelInfo.Caption:=
               Format('SFX Created %sOriginal Size %s %sCompressed Size %s Ratio %n %%',[#13,FormatFloat('#,',SrcFileStream.Size),#13,FormatFloat('#,',CompressedStream.Size),CompressedStream.Size*100/SrcFileStream.Size]);
               ProgressBarSfx.Position:=ProgressBarSfx.Max;
               ButtonCreateSFX.Enabled:=False;
            end
            else
            RaiseLastOSError
          else
          RaiseLastOSError
        else
        RaiseLastOSError;
    finally
      CompressedStream.Free;
    end;
  finally
    SrcFileStream.Free;
  end;
 except on e : exception do
   Application.MessageBox(PAnsiChar(e.Message),'Error',MB_OK+MB_ICONERROR);
 end;
end;

function TFrmCreateSFX.CreateStub:Boolean;
var
  StubStream: TResourceStream;
begin
  StubStream := TResourceStream.Create( HInstance, 'STUB', 'RT_RCDATA');
  try
     DeleteFile(FSfxFileName);
     StubStream.SaveToFile(FSfxFileName);
  finally
    StubStream.Free;
  end;
  Result:=FileExists(FSfxFileName);
end;

procedure TFrmCreateSFX.DoProgress(Sender: TObject);
begin
   ProgressBarSfx.Position:=TCustomZLibStream(Sender).Position;
   LabelInfo.Caption:=Format('Compressed %s bytes %n %%',[FormatFloat('#,',TCustomZLibStream(Sender).Position),100*TCustomZLibStream(Sender).Position/ProgressBarSfx.Max]);
   LabelInfo.Update;
end;

procedure TFrmCreateSFX.FormCreate(Sender: TObject);
begin
   LabelInfo.Caption:='';
end;

function TFrmCreateSFX.GetCompressionLevel: TCompressionLevel;
var
 i : Integer;
begin
  Result:=clMax;
    for i:= 0 to ComponentCount - 1 do
     if Components[i].ClassType = TRadioButton then
      if TRadioButton(Components[i]).Checked then
       Result:=TCompressionLevel(TRadioButton(Components[i]).Tag);
end;

end.

Notes:

* You can improve the final results if your rewrite the stub application using a library like KOL or avoid the use of the VCL using the WINAPI, to reduce the final exe size.

* These samples applications are for educational purposes only and not pretend be an alternative to another professional tools to generate a SFX file.

* The concept discussed in this entry can help you to build compressed and encrypted files using your own logic.

Check the full sourcecode on Github