Delphi DLL

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 DLL

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
zip: HCkZip;
entry: HCkZipEntry;
pdfData: HCkBinData;

begin
success := False;

zip := CkZip_Create();

// Open an existing ZIP archive.
success := CkZip_OpenZip(zip,'qa_data/zips/documents.zip');
if (success = False) then
  begin
    Memo1.Lines.Add(CkZip__lastErrorText(zip));
    Exit;
  end;

// Locate the PDF entry within the ZIP archive.
entry := CkZipEntry_Create();

success := CkZip_EntryOf(zip,'docs/report.pdf',entry);
if (success = False) then
  begin
    Memo1.Lines.Add('ZIP entry not found.');
    CkZip_CloseZip(zip);
    Exit;
  end;

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

success := CkZipEntry_UnzipToBd(entry,pdfData);
if (success = False) then
  begin
    Memo1.Lines.Add(CkZipEntry__lastErrorText(entry));
    Exit;
  end;

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

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

CkZip_CloseZip(zip);

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

CkZip_Dispose(zip);
CkZipEntry_Dispose(entry);
CkBinData_Dispose(pdfData);

end;