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

LOCAL loZip
LOCAL lnSuccess
LOCAL lcInZipFilename
LOCAL lcStrData
LOCAL lcStrCharset

loZip = CreateObject('Chilkat.Zip2')

*  Any string unlocks the component for the 1st 30-days.
lnSuccess = loZip.UnlockComponent("Anything for 30-day trial")
IF (lnSuccess <> 1) THEN
    =MESSAGEBOX(loZip.LastErrorText)
    QUIT
ENDIF

*  The NewZip method only initializes the Zip object -- it does
*  not create or write a .zip file.
lnSuccess = loZip.NewZip("notUsed.zip")
IF (lnSuccess <> 1) THEN
    =MESSAGEBOX(loZip.LastErrorText)
    QUIT
ENDIF

lcInZipFilename = "something.txt"
lcStrData = "abcdefghijklmnopqrstuvwxyz1234567890"
lcStrCharset = "iso-8859-1"
*  Append a string as a file to the existing zip object.
*  Please read the notes about strCharset below.
loZip.AppendString2(lcInZipFilename,lcStrData,lcStrCharset)

*  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.
lnSuccess = loZip.QuickAppend("preExisting.zip")
IF (lnSuccess <> 1) THEN
    =MESSAGEBOX(loZip.LastErrorText)
    QUIT
ENDIF

=MESSAGEBOX("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.