C

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

C

#include <C_CkZip.h>
#include <C_CkZipEntry.h>
#include <C_CkBinData.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkZip zip;
    HCkZipEntry entry;
    HCkBinData pdfData;

    success = FALSE;

    zip = CkZip_Create();

    // Open an existing ZIP archive.
    success = CkZip_OpenZip(zip,"qa_data/zips/documents.zip");
    if (success == FALSE) {
        printf("%s\n",CkZip_lastErrorText(zip));
        CkZip_Dispose(zip);
        return;
    }

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

    success = CkZip_EntryOf(zip,"docs/report.pdf",entry);
    if (success == FALSE) {
        printf("ZIP entry not found.\n");
        CkZip_CloseZip(zip);
        CkZip_Dispose(zip);
        CkZipEntry_Dispose(entry);
        return;
    }

    // ------------------------------------------------------------
    // 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) {
        printf("%s\n",CkZipEntry_lastErrorText(entry));
        CkZip_Dispose(zip);
        CkZipEntry_Dispose(entry);
        CkBinData_Dispose(pdfData);
        return;
    }

    printf("Uncompressed size = %d\n",CkBinData_getNumBytes(pdfData));
    printf("\n");

    // ------------------------------------------------------------
    // Optionally save the uncompressed bytes to a file.
    // 
    success = CkBinData_WriteFile(pdfData,"qa_output/report.pdf");
    if (success == FALSE) {
        printf("%s\n",CkBinData_lastErrorText(pdfData));
        CkZip_Dispose(zip);
        CkZipEntry_Dispose(entry);
        CkBinData_Dispose(pdfData);
        return;
    }

    CkZip_CloseZip(zip);

    printf("PDF extracted successfully.\n");


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

    }