PPMD Compression: String to Compressed Bytes

Demonstrates how to compress a string to a compressed byte array using PPMD.

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"

Dim strData As String
Dim i As Long

'  Create a long string to compress.
strData = "abcdefg1122334455667788"
strData = strData & vbCrLf
For i = 0 To 99
    strData = strData & "abcdefg1122334455667788"
    strData = strData & vbCrLf
Next

'  Depending on the programming language, the string
'  may be Unicode.  Tell the component to convert to
'  ansi (1-byte/char) prior to compression:
compress.Charset = "ansi"

'  PPMD compress the string:
Dim compressedBytes() As Byte
compressedBytes = compress.CompressString(strData)

'  Decompress back to the original:
Dim strOriginal As String
strOriginal = compress.DecompressString(compressedBytes)

'  Display the uncompressed original:
TextBox1.Text = TextBox1.Text & "--- Original ---" & vbCrLf
TextBox1.Text = TextBox1.Text & strOriginal & vbCrLf