(VBScript) Transition from BeginCompressStringENC to FirstChunk/LastChunk

Provides instructions for replacing deprecated BeginCompressStringENC method calls with using FirstChunk/LastChunk properties.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

success = 0

' This example assumes the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

set sbCompressedBase64 = CreateObject("Chilkat.StringBuilder")

set compress = CreateObject("Chilkat.Compression")
compress.Algorithm = "deflate"
compress.Charset = "utf-8"
compress.EncodingMode = "base64"

set sbIndex = CreateObject("Chilkat.StringBuilder")

' ----------------------------------------------------------------------------------
' This is the deprecated way of compressing in chunks using Begin/More/End methods..
' ----------------------------------------------------------------------------------

For i = 0 To 24
    ' Note: It is possible (and normal) for a BeginCompress* or MoreCompress* method to return
    ' an empty string (or 0 bytes).  When this happens, the input data is not lost.  It will be flushed
    ' in a subsequent call.
    sbIndex.Clear 
    success = sbIndex.AppendInt(i)
    If (i = 0) Then
        success = sbCompressedBase64.Append(compress.BeginCompressStringENC(sbIndex.GetAsString()))
    Else
        success = sbCompressedBase64.Append(compress.MoreCompressStringENC(sbIndex.GetAsString()))
    End If

    success = sbCompressedBase64.Append(compress.MoreCompressStringENC(": This is a line of data to be compressed..." & vbCrLf))
Next

' Flush any remaining output.
success = sbCompressedBase64.Append(compress.EndCompressStringENC())

outFile.WriteLine("The base64 encoded compressed text:")
outFile.WriteLine(sbCompressedBase64.GetAsString())

' Decompress in one call:
originalText = compress.DecompressStringENC(sbCompressedBase64.GetAsString())
outFile.WriteLine(originalText)

' ----------------------------------------------------------------------------------
' This is new way of compressing in chunks using FirstChunk and LastChunk properties
' ----------------------------------------------------------------------------------

sbCompressedBase64.Clear 

compress.FirstChunk = 1
compress.LastChunk = 0

set bdCompressed = CreateObject("Chilkat.BinData")
set sbUncompressedChunk = CreateObject("Chilkat.StringBuilder")

For i = 0 To 24
    If (i = 24) Then
        compress.LastChunk = 1
    End If

    sbUncompressedChunk.Clear 
    success = sbUncompressedChunk.AppendInt(i)
    success = sbUncompressedChunk.Append(": This is a line of data to be compressed..." & vbCrLf)

    success = compress.CompressSb(sbUncompressedChunk,bdCompressed)

    compress.FirstChunk = 0
Next

outFile.WriteLine("The base64 encoded compressed text:")
outFile.WriteLine(bdCompressed.GetEncoded("base64"))

' Decompress in one call:
originalText = compress.DecompressStringENC(bdCompressed.GetEncoded("base64"))
outFile.WriteLine(originalText)

outFile.Close