(VB.NET) Unzip Binary File to Stream

Demonstrates how to unzip a large binary file to a stream to allow the application to process the uncompressed bytes chunk by chunk.

Note: This example requires Chilkat v9.5.0.67 or greater.

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' This requires the Chilkat Zip API to have been previously unlocked.
' See Unlock Chilkat Zip for sample code.

Dim zip As New Chilkat.Zip

' First open a .zip.
Dim success As Boolean = zip.OpenZip("qa_data/zips/big.zip")
If (success <> True) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


' Get the entry to be unzipped to a stream..
Dim entry As Chilkat.ZipEntry = zip.GetEntryByIndex(0)
If (zip.LastMethodSuccess <> True) Then
    Debug.WriteLine(zip.LastErrorText)
    Exit Sub
End If


Dim dataStream As New Chilkat.Stream

Dim unzipTask As Chilkat.Task = entry.UnzipToStreamAsync(dataStream)
If (entry.LastMethodSuccess <> True) Then
    Debug.WriteLine(entry.LastErrorText)

    Exit Sub
End If


' Start the background unzip thread.
unzipTask.Run()

' We'll read the uncompressed data chunk-by-chunk and write to an output file.
Dim fac As New Chilkat.FileAccess
success = fac.OpenForWrite("qa_output/out.dat")
If (success <> True) Then
    Debug.WriteLine(fac.LastErrorText)

    Exit Sub
End If


' Read the stream.  (this is reading the unzipped file data)
Dim bd As New Chilkat.BinData
While dataStream.EndOfStream <> True
    ' Get the next chunk of decompressed bytes.
    dataStream.ReadBd(bd)
    ' Do something with it..
    ' In this simple example, we'll just write to the file.
    fac.FileWriteBd(bd,0,0)
    ' Clear for the next read.
    bd.Clear()
End While

fac.FileClose()



Debug.WriteLine("Success.")