{
  Parameters: 

  FileToSplit: Specify a file to split. 
  SizeofFiles: Specify the size of the files you want to split to (in bytes) 
  Progressbar: Specify a TProgressBar to show the splitting progress 

  Result: 
  SplitFile() will create files  FileName.001, FileName.002, FileName.003 and so on 
  that are SizeofFiles bytes in size. 
 } 

function SplitFile(FileName : TFileName; SizeofFiles : Integer;
ProgressBar : TProgressBar) : Boolean;
var
  i : Word; 
  fs, sStream: TFileStream; 
  SplitFileName: String; 
begin
  ProgressBar.Position := 0; 
  fs := TFileStream.Create(FileName, fmOpenRead or fmShareDenyWrite); 
  try 
    for i := 1 to Trunc(fs.Size / SizeofFiles) + 1 do 
    begin 
      SplitFileName := ChangeFileExt(FileName, '.'+ FormatFloat('000', i)); 
      sStream := TFileStream.Create(SplitFileName, fmCreate or fmShareExclusive); 
      try 
        if fs.Size - fs.Position < SizeofFiles then 
          SizeofFiles := fs.Size - fs.Position; 
        sStream.CopyFrom(fs, SizeofFiles); 
        ProgressBar.Position := Round((fs.Position / fs.Size) * 100); 
      finally 
        sStream.Free; 
      end; 
    end; 
  finally 
    fs.Free; 
  end; 

end; 

// Combine files / Dateien zusammenfьhren 

{ 
  Parameters: 

  FileName: Specify the first piece of the splitted files 
  CombinedFileName: Specify the combined file name. (the output file) 

  Result: 
  CombineFiles() will create one large file from the pieces 
 } 

function CombineFiles(FileName, CombinedFileName : TFileName) : Boolean; 
var 
  i: integer; 
  fs, sStream: TFileStream; 
  filenameOrg: String; 
begin 
  i := 1; 
  fs := TFileStream.Create(CombinedFileName, fmCreate or fmShareExclusive); 
  try 
    while FileExists(FileName) do 
    begin 
      sStream := TFileStream.Create(FileName, fmOpenRead or fmShareDenyWrite); 
      try 
        fs.CopyFrom(sStream, 0); 
      finally 
        sStream.Free; 
      end; 
      Inc(i); 
      FileName := ChangeFileExt(FileName, '.'+ FormatFloat('000', i)); 
    end; 
  finally 
    fs.Free; 
  end; 
end; 

// Examples: 

procedure TForm1.Button1Click(Sender: TObject); 
begin 
  SplitFile('C:\temp\FileToSplit.chm',1000000, ProgressBar1); 
end; 

procedure TForm1.Button2Click(Sender: TObject); 
begin 
  CombineFiles('C:\temp\FileToSplit.001','H:\temp\FileToSplit.chm'); 
end;