(MFC) Chilkat Zip API Concepts

This example helps clarify some common misconceptions w/ using the Chilkat Zip API.

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

See Also: Using MFC CString in Chilkat

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

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkZip zip;

    // To clarify some concepts, this example will create a new .zip containing 2 files.

    // The NewZip method is called to initialize the zip object to a new and empty state.
    // It does not actually create the .zip file.  It simply intializes the object.
    // if the zip object did not contain anything previously, then this method could be skipped
    // altogether.  It has the side-effect of setting the zip.FileName property.
    bool success = zip.NewZip("test.zip");
    if (success != true) {
        strOut.append(zip.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // The FileName property should now contain "test.zip".  This is the name of the .zip
    // that is written when WriteZip or WriteZipAndClose is called.
    strOut.append("zip filename = ");
    strOut.append(zip.fileName());
    strOut.append("\r\n");

    // When a file is "appended" to the zip object, we are really just appending a reference
    // to the file in the filesystem.  A "zip entry" is added to the zip object and this entry
    // can be one of several types.  It can point to a file.  It can contain uncompressed binary
    // or text data, it can point to an entry in the already-opened zip (if we had called OpenZip 
    // instead), etc.  

    // Now.. add a reference to a single file by calling AppendOneFileOrDir
    // Note: On Windows, forward slashes are equivalent to backslashes
    bool saveExtraPath = false;
    success = zip.AppendOneFileOrDir("/temp/abc123/HelloWorld123.txt",saveExtraPath);
    if (success != true) {
        strOut.append(zip.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // We now have a zip object with one entry, which points to the file /temp/abc123/HelloWorld123.txt
    // If desired, we could change the filename of the zip entry so that when the zip is written,
    // the file has a different name:
    CkZipEntry *entry = zip.GetEntryByIndex(0);
    entry->put_FileName("helloWorld.txt");
    delete entry;

    // When the zip is actually written, the entry's data will stream from /temp/abc123/HelloWorld123.txt
    // and be compressed into an entry within the .zip having the filename "helloWorld.txt"

    // Now add another entry, this time from a string containing the file content:
    entry = zip.AppendString2("HelloWorld2.txt","hello world!","utf-8");
    delete entry;

    // Examine the entries in the zip so far..
    // Each entry can be one of the following types:

    // 0 -- Mapped Entry: An entry in an existing Zip file.
    // 1 -- File Entry: A file not yet in memory, but referenced. 
    //      These entries are added by calling AppendFiles, AppendFilesEx, AppendOneFileOrDir, etc.
    // 2 -- Data Entry: An entry containing uncompressed data from memory. 
    //      These entries are added by calling AppendData, AppendString, etc.
    // 3 -- Null Entry: An entry that no longer exists in the .zip.
    // 4 -- New Directory Entry: A directory entry added by calling AppendNewDir. 

    int i;
    int n = zip.get_NumEntries();
    for (i = 0; i <= n - 1; i++) {

        entry = zip.GetEntryByIndex(i);
        strOut.append(entry->fileName());
        strOut.append(", type=");
        strOut.appendInt(entry->get_EntryType());
        strOut.append("\r\n");
        delete entry;
    }

    // Write the "test.zip" file.
    success = zip.WriteZip();
    if (success != true) {
        strOut.append(zip.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Our zip object still contains 2 entries, but now they point to the entries within the 
    // test.zip  (We called WriteZip, which writes the .zip but does not close it.  Instead,
    // the entries of the zip object are updated to become "mapped" entries.
    // For example:

    n = zip.get_NumEntries();
    for (i = 0; i <= n - 1; i++) {

        entry = zip.GetEntryByIndex(i);
        strOut.append(entry->fileName());
        strOut.append(", type=");
        strOut.appendInt(entry->get_EntryType());
        strOut.append("\r\n");
        delete entry;
    }

    // Finally, close the zip
    zip.CloseZip();


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }