C++

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

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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

C++

#include <CkZip.h>
#include <CkZipEntry.h>
#include <CkBinData.h>

void ChilkatSample(void)
    {
    bool success = false;

    CkZip zip;

    // Open an existing ZIP archive.
    success = zip.OpenZip("qa_data/zips/documents.zip");
    if (success == false) {
        std::cout << zip.lastErrorText() << "\r\n";
        return;
    }

    // Locate the PDF entry within the ZIP archive.
    CkZipEntry entry;

    success = zip.EntryOf("docs/report.pdf",entry);
    if (success == false) {
        std::cout << "ZIP entry not found." << "\r\n";
        zip.CloseZip();
        return;
    }

    // ------------------------------------------------------------
    // Inflate the ZIP entry directly into a BinData object.
    // 
    // The uncompressed bytes are stored entirely in memory.
    // 
    CkBinData pdfData;

    success = entry.UnzipToBd(pdfData);
    if (success == false) {
        std::cout << entry.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Uncompressed size = " << pdfData.get_NumBytes() << "\r\n";
    std::cout << "" << "\r\n";

    // ------------------------------------------------------------
    // Optionally save the uncompressed bytes to a file.
    // 
    success = pdfData.WriteFile("qa_output/report.pdf");
    if (success == false) {
        std::cout << pdfData.lastErrorText() << "\r\n";
        return;
    }

    zip.CloseZip();

    std::cout << "PDF extracted successfully." << "\r\n";
    }