PowerBuilder

Unzip One File to a Stream

See more Zip Examples

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

integer li_rc
integer li_Success
oleobject loo_Zip
oleobject loo_Entry
oleobject loo_StreamA
oleobject loo_StreamB
oleobject loo_UnzipTask
oleobject loo_Sb
oleobject loo_StreamC
string s

li_Success = 0

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

loo_Zip = create oleobject
li_rc = loo_Zip.ConnectToNewObject("Chilkat.Zip")
if li_rc < 0 then
    destroy loo_Zip
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// First open a .zip.
li_Success = loo_Zip.OpenZip("qa_data/hamlet.zip")
if li_Success = 0 then
    Write-Debug loo_Zip.LastErrorText
    destroy loo_Zip
    return
end if

// Find the entry to be unzipped to a stream..
loo_Entry = create oleobject
li_rc = loo_Entry.ConnectToNewObject("Chilkat.ZipEntry")

li_Success = loo_Zip.EntryMatching("*hamlet.xml",loo_Entry)
if li_Success = 0 then
    Write-Debug loo_Zip.LastErrorText
    destroy loo_Zip
    destroy loo_Entry
    return
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.
loo_StreamA = create oleobject
li_rc = loo_StreamA.ConnectToNewObject("Chilkat.Stream")

loo_StreamA.SinkFile = "qa_output/hamletA.xml"

li_Success = loo_Entry.UnzipToStream(loo_StreamA)
if li_Success <> 1 then
    Write-Debug loo_Entry.LastErrorText
    destroy loo_Zip
    destroy loo_Entry
    destroy loo_StreamA
    return
end if

// Close the stream to close the output file.
li_Success = loo_StreamA.WriteClose()

// ----------------------------------------------------------------
// Case 2a: Uzip to a stream asynchronously. 
loo_StreamB = create oleobject
li_rc = loo_StreamB.ConnectToNewObject("Chilkat.Stream")

loo_UnzipTask = loo_Entry.UnzipToStreamAsync(loo_StreamB)
if loo_Entry.LastMethodSuccess <> 1 then
    Write-Debug loo_Entry.LastErrorText
    destroy loo_Zip
    destroy loo_Entry
    destroy loo_StreamA
    destroy loo_StreamB
    return
end if

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

// Read the stream.  (this is reading the unzipped file data)
loo_Sb = create oleobject
li_rc = loo_Sb.ConnectToNewObject("Chilkat.StringBuilder")

do while loo_StreamB.EndOfStream <> 1
    // Each call to ReadSb appends to the contents of sb.
    loo_StreamB.ReadSb(loo_Sb)
loop
loo_Sb.WriteFile("qa_output/hamletB.xml","utf-8",0)

destroy loo_UnzipTask
Write-Debug "Success."

// ----------------------------------------------------------------
// Case 2b: Uzip to a stream asynchronously and emit output while reading. 
loo_StreamC = create oleobject
li_rc = loo_StreamC.ConnectToNewObject("Chilkat.Stream")

loo_UnzipTask = loo_Entry.UnzipToStreamAsync(loo_StreamC)
if loo_Entry.LastMethodSuccess <> 1 then
    Write-Debug loo_Entry.LastErrorText
    destroy loo_Zip
    destroy loo_Entry
    destroy loo_StreamA
    destroy loo_StreamB
    destroy loo_Sb
    destroy loo_StreamC
    return
end if

loo_UnzipTask.Run()

do while loo_StreamC.EndOfStream <> 1
    s = loo_StreamC.ReadString()
    Write-Debug s
loop

destroy loo_UnzipTask
Write-Debug "Success."


destroy loo_Zip
destroy loo_Entry
destroy loo_StreamA
destroy loo_StreamB
destroy loo_Sb
destroy loo_StreamC