(MFC) GZip Create / Extract .gz File

Demonstrates how to compress a file to create a .gz (GZip) file.

Note: The .gz file format is a compressed file format. It contains a single file. The .gz file format is not an archive format (i.e. it does not contain a collection of files/directories such as with the .zip, .rar, or .tar file formats). GZip is often combined with TAR to create a .tgz (or .tar.gz).

Note: It is possible for a .gz to contain more than one file, but this is very uncommon.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkGzip.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkGzip gzip;

    // File-to-file GZip:
    // Compress "hamlet.xml" to create "hamlet.xml.gz"
    bool success = gzip.CompressFile("hamlet.xml","hamlet.xml.gz");
    if (success != true) {
        strOut.append(gzip.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // File-to-file ungzip
    // Decompress "hamlet.xml.gz" to create "hamletOut.xml"
    success = gzip.UncompressFile("hamlet.xml.gz","hamletOut.xml");
    if (success != true) {
        strOut.append(gzip.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // File-to-string ungzip
    // Decompress the contents of a .gz directly to a string variable:
    // The 2nd argument indicates the charset of the character
    // data after it is decompressed.
    const char *xmlStr = 0;
    xmlStr = gzip.uncompressFileToString("hamlet.xml.gz","utf-8");
    if (success != true) {
        strOut.append(gzip.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append(xmlStr);
    strOut.append("\r\n");

    // The Chilkat GZip API provides much more flexibility than shown
    // here.  See the reference documentation at 
    // http://www.chilkatsoft.com/refdoc for more information


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }