Append In-Memory Data to Existing Zip w/out Rewriting Entire Zip

Demonstrates how to use the QuickAppend method to append in-memory data (string or byte array) to an existing .zip archive. This method works by editing the existing .zip -- it does not rewrite or recompress the contents of the existing .zip. It is the fastest way to append additional files or data to a pre-existing large .zip archive. Note: The QuickAppend method is new and available in the pre-release downloads, or in official releases dated after 6-October-2007.

Download Chilkat Zip ActiveX

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
zip: TChilkatZip2;
success: Integer;
inZipFilename: String;
strData: String;
strCharset: String;

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;

//  The NewZip method only initializes the Zip object -- it does
//  not create or write a .zip file.
success := zip.NewZip('notUsed.zip');
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);

  end;

inZipFilename := 'something.txt';
strData := 'abcdefghijklmnopqrstuvwxyz1234567890';
strCharset := 'iso-8859-1';
//  Append a string as a file to the existing zip object.
//  Please read the notes about strCharset below.
zip.AppendString2(inZipFilename,strData,strCharset);

//  Note: The AppendString method is identical to AppendString2,
//  except the strCharset argument is omitted and it is assumed
//  you desire the ANSI charset.

//  Note: You may append a byte array (or Variant containing
//  a byte array for ActiveX users) by calling AppendData.

//  Appends the contents of this zip object to the preExisting.zip
//  zip archive.  preExisting.zip is opened, and the files
//  referenced by this zip object are streamed in, compressed,
//  and appended to the end of the archive.
success := zip.QuickAppend('preExisting.zip');
if (success <> 1) then
  begin
    ShowMessage(zip.LastErrorText);

  end;

ShowMessage('Success!');

//  Note about strCharset:
//  string variables in many programming language are Unicode.
//  It is likely that you don't want to create .zip that contains
//  a text file that will unzip to Unicode characters (2 bytes/char).
//  The strCharset argument allows you to specify the exact
//  charset to use.  When the string is added to the .zip, it
//  is first converted to this charset.  English strings
//  may use "us-ascii".  Western-European languages typically
//  use "iso-8859-1" or "windows-1252".  Japanese might choose
//  between "shift_jis", "iso-2022-jp", "euc-jp", etc.
//  Chilkat supports all major character encodings.
//  You may always use "ansi" or "utf-8".

//  Note: Additional files, directory trees, or in-memory data
//  can be appended by calling AppendOneFileOrDir, AppendFiles,
//  AppendString, AppendData, etc. multiple times.
//  Whatever files and/or in-memory data that are referenced by
//  this zip object will be appended to preExisting.zip when
//  QuickAppend is called.

end;