VB.NET

Transition from BeginCompressStringENC to FirstChunk/LastChunk

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

Dim success As Boolean = False

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

Dim sbCompressedBase64 As New Chilkat.StringBuilder

Dim compress As New Chilkat.Compression
compress.Algorithm = "deflate"
compress.Charset = "utf-8"
compress.EncodingMode = "base64"

Dim sbIndex As New Chilkat.StringBuilder

' ----------------------------------------------------------------------------------
' This is the deprecated way of compressing in chunks using Begin/More/End methods..
' ----------------------------------------------------------------------------------
Dim i As Integer
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()
    sbIndex.AppendInt(i)
    If (i = 0) Then
        sbCompressedBase64.Append(compress.BeginCompressStringENC(sbIndex.GetAsString()))
    Else
        sbCompressedBase64.Append(compress.MoreCompressStringENC(sbIndex.GetAsString()))
    End If

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

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

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

' Decompress in one call:
Dim originalText As String = compress.DecompressStringENC(sbCompressedBase64.GetAsString())
Debug.WriteLine(originalText)

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

sbCompressedBase64.Clear()

compress.FirstChunk = True
compress.LastChunk = False

Dim bdCompressed As New Chilkat.BinData
Dim sbUncompressedChunk As New Chilkat.StringBuilder

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


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

    compress.CompressSb(sbUncompressedChunk,bdCompressed)

    compress.FirstChunk = False
Next

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

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