(Visual Basic 6.0) Unzip One File to a Stream

Demonstrates how to unzip a particular file contained within a .zip archive to a Chilkat stream.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

Dim zip As New ChilkatZip

' First open a .zip.
Dim success As Long
success = zip.OpenZip("qa_data/hamlet.zip")
If (success <> 1) Then
    Debug.Print zip.LastErrorText
    Exit Sub
End If

' Find the entry to be unzipped to a stream..
Dim entry As ChilkatZipEntry
Set entry = zip.FirstMatchingEntry("*hamlet.xml")
If (zip.LastMethodSuccess <> 1) Then
    Debug.Print zip.LastErrorText
    Exit Sub
End If

' There are three ways we can unzip (inflate) to a stream.
' 
' 1) Set a sink file on the stream object and call UnzipToStream synchronously.
'    This unzips to the stream's sink (which is to simply unzip to a file in the filesystem).
' 
' 2) Create a stream object and call UnzipToStreamAsync.  This starts the unzip in a background
'    thread (after Task.Run is called).  Your application can then read the unzipped (inflated) file
'    directly from the stream.
' 
' 3) (not shown in this example) Unzip to a stream object that is the source of something else.
'    

' ----------------------------------------------------------------
' Case 1: Unzip to a file by setting the sink of streamA to a file.
Dim streamA As New ChilkatStream
streamA.SinkFile = "qa_output/hamletA.xml"

success = entry.UnzipToStream(streamA)
If (success <> 1) Then
    Debug.Print entry.LastErrorText

    Exit Sub
End If

' Close the stream to close the output file.
success = streamA.WriteClose()

' ----------------------------------------------------------------
' Case 2a: Uzip to a stream asynchronously. 
Dim streamB As New ChilkatStream

Dim unzipTask As ChilkatTask
Set unzipTask = entry.UnzipToStreamAsync(streamB)
If (entry.LastMethodSuccess <> 1) Then
    Debug.Print entry.LastErrorText

    Exit Sub
End If

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

' Read the stream.  (this is reading the unzipped file data)
Dim sb As New ChilkatStringBuilder
Do While streamB.EndOfStream <> 1
    ' Each call to ReadSb appends to the contents of sb.
    success = streamB.ReadSb(sb)
Loop
success = sb.WriteFile("qa_output/hamletB.xml","utf-8",0)

Debug.Print "Success."

' ----------------------------------------------------------------
' Case 2b: Uzip to a stream asynchronously and emit output while reading. 
Dim streamC As New ChilkatStream

Set unzipTask = entry.UnzipToStreamAsync(streamC)
If (entry.LastMethodSuccess <> 1) Then
    Debug.Print entry.LastErrorText

    Exit Sub
End If

success = unzipTask.Run()

Do While streamC.EndOfStream <> 1
    Dim s As String
    s = streamC.ReadString()
    Debug.Print s
Loop

Debug.Print "Success."