Append File and Rename within Zip

Download Chilkat Zip ActiveX (includes objects for .zip, .gz, .bz2, and .Z)

How to append an additional file to a .zip and rename it within the .zip.

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    ChilkatZip2Lib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
zip: TChilkatZip2;
success: Integer;
numEntries: Integer;
saveExtraPath: Integer;
entry: IChilkatZipEntry2;

begin
zip := TChilkatZip2.Create(Self);

//  Any string unlocks the component for the 1st 30-days.
success := zip.UnlockComponent('Anything for 30-day trial');
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);

  end;

//  Open an existing .zip.
//  Note: Opening a zip does not read the entire zip into memory.
//  It simply opens the zip and makes it ready for unzipping
//  or retrieving information and/or data.
success := zip.OpenZip('a.zip');
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);

  end;

//  Save the current number of entries.
numEntries := zip.NumEntries;

//  Append a new file to the .zip.
//  The new entry is at index numEntries (indexing begins at 0).
//  Note: The AppendOneFileOrDir simply adds a reference to the
//  file to the zip object.  The file is not actually read
//  or physically added to the .zip file until the WriteZip or
//  WriteZipAndClose method is called.
saveExtraPath := 0;
success := zip.AppendOneFileOrDir('hamlet.xml',saveExtraPath);
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);

  end;

//  Get the entry we just added:

entry := zip.GetEntryByIndex(numEntries);

//  Change the filename.
//  The zip component remembers the file referenced in the filesystem.
//  When the zip is written, the "hamlet.xml" file is read and
//  compressed, but the filename within the zip will be "shakespearePlay.xml".
entry.FileName := 'shakespearePlay.xml';

//  Write the .zip
//  The Chilkat Zip component always writes to a temporary file
//  first.  This is to ensure that (in cases like this), if something
//  goes wrong we don't lose the original .zip.  If the write
//  finishes without error, it is moved to the destination
//  file, thus overwriting it.  The TempDir property controls
//  the directory where the temp zip is written.
success := zip.WriteZipAndClose();
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);

  end;
end;