Delphi ActiveX

Unzip a ZIP Entry Directly into a BinData Object Using ZipEntry.UnzipToBd

See more Zip Examples

This example demonstrates how to use the ZipEntry.UnzipToBd method to inflate a ZIP entry directly into a BinData object.

The entry contents are uncompressed entirely in memory without creating a file on disk.

This is useful when:

• Processing ZIP entry data entirely in memory
• Avoiding temporary filesystem files
• Working with binary files such as images, PDFs, or certificates
• Passing uncompressed ZIP data directly to other APIs

The example opens a ZIP archive, locates a PDF entry, inflates it into a BinData object, and then writes the uncompressed bytes to a new file.

Suppose the ZIP archive contains:

docs/report.pdf

The entry is uncompressed directly into memory before optionally being saved to:

qa_output/report.pdf

Delphi ActiveX

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
success: Integer;
zip: TChilkatZip;
entry: TChilkatZipEntry;
pdfData: TChilkatBinData;

begin
success := 0;

zip := TChilkatZip.Create(Self);

// Open an existing ZIP archive.
success := zip.OpenZip('qa_data/zips/documents.zip');
if (success = 0) then
  begin
    Memo1.Lines.Add(zip.LastErrorText);
    Exit;
  end;

// Locate the PDF entry within the ZIP archive.
entry := TChilkatZipEntry.Create(Self);

success := zip.EntryOf('docs/report.pdf',entry.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add('ZIP entry not found.');
    zip.CloseZip();
    Exit;
  end;

// ------------------------------------------------------------
// Inflate the ZIP entry directly into a BinData object.
// 
// The uncompressed bytes are stored entirely in memory.
// 
pdfData := TChilkatBinData.Create(Self);

success := entry.UnzipToBd(pdfData.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(entry.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Uncompressed size = ' + IntToStr(pdfData.NumBytes));
Memo1.Lines.Add('');

// ------------------------------------------------------------
// Optionally save the uncompressed bytes to a file.
// 
success := pdfData.WriteFile('qa_output/report.pdf');
if (success = 0) then
  begin
    Memo1.Lines.Add(pdfData.LastErrorText);
    Exit;
  end;

zip.CloseZip();

Memo1.Lines.Add('PDF extracted successfully.');
end;