(Lianja) 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.

loZip = createobject("CkZip")

// First open a .zip.
llSuccess = loZip.OpenZip("qa_data/zips/big.zip")
if (llSuccess <> .T.) then
    ? loZip.LastErrorText
    release loZip
    return
endif

// Get the entry to be unzipped to a stream..
loEntry = loZip.GetEntryByIndex(0)
if (loZip.LastMethodSuccess <> .T.) then
    ? loZip.LastErrorText
    release loZip
    return
endif

loDataStream = createobject("CkStream")

loUnzipTask = loEntry.UnzipToStreamAsync(loDataStream)
if (loEntry.LastMethodSuccess <> .T.) then
    ? loEntry.LastErrorText
    release loEntry
    release loZip
    release loDataStream
    return
endif

// Start the background unzip thread.
loUnzipTask.Run()

// We'll read the uncompressed data chunk-by-chunk and write to an output file.
loFac = createobject("CkFileAccess")
llSuccess = loFac.OpenForWrite("qa_output/out.dat")
if (llSuccess <> .T.) then
    ? loFac.LastErrorText
    release loEntry
    release loZip
    release loDataStream
    release loFac
    return
endif

// Read the stream.  (this is reading the unzipped file data)
loBd = createobject("CkBinData")
do while loDataStream.EndOfStream <> .T.
    // Get the next chunk of decompressed bytes.
    loDataStream.ReadBd(loBd)
    // Do something with it..
    // In this simple example, we'll just write to the file.
    loFac.FileWriteBd(loBd,0,0)
    // Clear for the next read.
    loBd.Clear()
enddo

loFac.FileClose()

release loEntry
release loUnzipTask
? "Success."


release loZip
release loDataStream
release loFac
release loBd