(Delphi ActiveX) 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.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
zip: TChilkatZip;
success: Integer;
entry: IChilkatZipEntry;
dataStream: TChilkatStream;
unzipTask: IChilkatTask;
fac: TCkFileAccess;
bd: TChilkatBinData;

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

zip := TChilkatZip.Create(Self);

// First open a .zip.
success := zip.OpenZip('qa_data/zips/big.zip');
if (success <> 1) then
  begin
    Memo1.Lines.Add(zip.LastErrorText);
    Exit;
  end;

// Get the entry to be unzipped to a stream..
entry := zip.GetEntryByIndex(0);
if (zip.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(zip.LastErrorText);
    Exit;
  end;

dataStream := TChilkatStream.Create(Self);

unzipTask := entry.UnzipToStreamAsync(dataStream.ControlInterface);
if (entry.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(entry.LastErrorText);

    Exit;
  end;

// Start the background unzip thread.
unzipTask.Run();

// We'll read the uncompressed data chunk-by-chunk and write to an output file.
fac := TCkFileAccess.Create(Self);
success := fac.OpenForWrite('qa_output/out.dat');
if (success <> 1) then
  begin
    Memo1.Lines.Add(fac.LastErrorText);

    Exit;
  end;

// Read the stream.  (this is reading the unzipped file data)
bd := TChilkatBinData.Create(Self);
while dataStream.EndOfStream <> 1 do
  begin
    // Get the next chunk of decompressed bytes.
    dataStream.ReadBd(bd.ControlInterface);
    // Do something with it..
    // In this simple example, we'll just write to the file.
    fac.FileWriteBd(bd.ControlInterface,0,0);
    // Clear for the next read.
    bd.Clear();
  end;

fac.FileClose();

Memo1.Lines.Add('Success.');
end;