PPMD Compression: String to Compressed Bytes

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

Download Chilkat Compression ActiveX

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
Set outFile = fso.CreateTextFile("output.txt", True)

set compress = CreateObject("Chilkat.Compression")

'  Any string argument automatically begins a 30-day trial.
success = compress.UnlockComponent("30-day trial")
If (success <> 1) Then
    MsgBox "Compression component unlock failed"
    WScript.Quit
End If

compress.Algorithm = "ppmd"

'  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:
compressedBytes = compress.CompressString(strData)

'  Decompress back to the original:

strOriginal = compress.DecompressString(compressedBytes)

'  Display the uncompressed original:
outFile.WriteLine("--- Original ---")
outFile.WriteLine(strOriginal)
outFile.Close