PPMD Compress File

Demonstrates how to use the PPMD compression algorithm to compress a file. This code is capable of compressing any size file because the file data is compressed from input to output in a streaming mode. The output file does not contain any "PPMD" header -- it is purely PPMD compressed data.

The functionality in this example is available in pre-release only:
To use, unzip and add a reference to the enclosed DLL in your .NET project.

Download Chilkat .NET for 2.0 / 3.5 Framework

Download Chilkat .NET for 1.0 / 1.1 Framework

Dim compress As New Chilkat.Compression()

'  Any string argument automatically begins a 30-day trial.
Dim success As Boolean
success = compress.UnlockComponent("30-day trial")
If (success <> true) Then
    MsgBox("Compression component unlock failed")
    Exit Sub
End If


compress.Algorithm = "ppmd"

success = compress.CompressFile("hamlet.xml","hamletPpmd.dat")
If (success <> true) Then
    MsgBox(compress.LastErrorText)
    Exit Sub
End If


'  Decompress back to the original:
success = compress.DecompressFile("hamletPpmd.dat","hamletInflated.xml")
If (success <> true) Then
    MsgBox(compress.LastErrorText)
    Exit Sub
End If


TextBox1.Text = TextBox1.Text & "Success!" & vbCrLf