XZip and XUnzip - Add zip and/or unzip to your app with no extra .lib or .dll

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Introduction

I have already introduced XZip in a previous article. This article presents XZip and also XUnzip, which together allow you to add zip and unzip to your application without using any .lib or .dll.

First, let me acknowledge the work of Lucian Wischik, who took the many .c and .h files from Info-ZIP and produced the .cpp and .h files that XZip is based on.

XZip and XUnzip Features

Most of the functions are demonstrated in the XZip demo app. Here are the main ones:

• CreateZip() - Create a zip archive file.

//////////////////////////////////////////////////////////////////////////////
//
// CreateZip()
//
// Purpose:     Create a zip archive file
//
// Parameters:  z     - archive file name if flags is ZIP_FILENAME;  for other
//                       uses see below
//              len   - for memory (ZIP_MEMORY) should be the buffer size;
//                       for other uses, should be 0
//              flags - indicates usage, see below;  for files, this will be
//                       ZIP_FILENAME
//
// Returns:     HZIP  - non-zero if zip archive created ok, otherwise 0
//

• ZipAdd() - Add a file to a zip archive.

//////////////////////////////////////////////////////////////////////////////
//
// ZipAdd()
//
// Purpose:     Add a file to a zip archive
//
// Parameters: hz      - handle to an open zip archive
//             dstzn   - name used inside the zip archive to identify the file
//             src     - for a file (ZIP_FILENAME) this specifies the filename
//                        to be added to the archive;  for other uses, see 
//                        below
//             len     - for memory (ZIP_MEMORY) this specifies the buffer
//                        length;  for other uses, this should be 0
//             flags   - indicates usage, see below;  for files, this will be
//                        ZIP_FILENAME
//
// Returns:    ZRESULT - ZR_OK if success, otherwise some other value
//

• OpenZip() - Open an existing zip archive file.

//////////////////////////////////////////////////////////////////////////////
//
// OpenZip()
//
// Purpose:     Open an existing zip archive file
//
// Parameters:  z      - archive file name if flags is ZIP_FILENAME;  for 
//                        other uses see below
//              len    - for memory (ZIP_MEMORY) should be the buffer size;
//                       for other uses, should be 0
//              flags  - indicates usage, see below;  for files, this will be
//                       ZIP_FILENAME
//
// Returns:     HZIP   - non-zero if zip archive opened ok, otherwise 0
//

• GetZipItem() - Get information about an item in an open zip archive.

//////////////////////////////////////////////////////////////////////////////
//
// GetZipItem()
//
// Purpose:     Get information about an item in an open zip archive
//
// Parameters:  hz      - handle of open zip archive
//              index   - index number (0 based) of item in zip
//              ze      - pointer to a ZIPENTRY (if ANSI) or ZIPENTRYW struct
//                        (if Unicode)
//
// Returns:     ZRESULT - ZR_OK if success, otherwise some other value
//

• FindZipItem() - Find item by name and return information about it.

//////////////////////////////////////////////////////////////////////////////
//
// FindZipItem()
//
// Purpose:     Find item by name and return information about it
//
// Parameters:  hz      - handle of open zip archive
//              name    - name of file to look for inside zip archive
//              ic      - TRUE = case insensitive
//              index   - pointer to index number returned, or -1
//              ze      - pointer to a ZIPENTRY (if ANSI) or ZIPENTRYW struct
//                        (if Unicode)
//
// Returns:     ZRESULT - ZR_OK if success, otherwise some other value
//

• UnzipItem() - Find item by index and unzip it.

//////////////////////////////////////////////////////////////////////////////
//
// UnzipItem()
//
// Purpose:     Find item by index and unzip it
//
// Parameters:  hz      - handle of open zip archive
//              index   - index number of file to unzip
//              dst     - target file name of unzipped file
//              len     - for memory (ZIP_MEMORY. length of buffer;
//                        otherwise 0
//              flags   - indicates usage, see below;  for files, this will be
//                        ZIP_FILENAME
//
// Returns:     ZRESULT - ZR_OK if success, otherwise some other value
//

• CloseZip() - Close an open zip archive.

//////////////////////////////////////////////////////////////////////////////
//
// CloseZip()
//
// Purpose:     Close an open zip archive
//
// Parameters:  hz      - handle to an open zip archive
//
// Returns:     ZRESULT - ZR_OK if success, otherwise some other value
//

How To Use

To integrate XZip into your app, you first need to add following the files to your project:

• XZip.cpp
• XZip.h
• XUnzip.cpp
• XUnzip.h

If you include XZip in a project that uses precompiled headers, you must change C/C++ Precompiled Headers settings to Not using precompiled headers for XZip.cpp and XUnzip.cpp.

Next, include the header files XZip.h and XUnzip.h in appropriate project files. Now you are ready to start using XZip. There are many notes concerning usage of various functions in XZip.h and XUnzip.h. Please read all function headers for each function you wish to use.

Known Limitations

XZip and XUnzip have been tested only with files.

Demo App

The XZipTest.exe demo tests the APIs in XZip and XUnzip. Here is some of the output:

Frequently Asked Questions

1. Can I use XZip in non-MFC apps?
   Yes. It has been implemented to compile with any Win32 program.
2. When I try to include XZip.cpp in my MFC project, I get the compiler error XZip.cpp(2918) : fatal error C1010: unexpected end of file while looking for precompiled header directive. How can I fix this?
   When using XZip in project that uses precompiled headers, you must change C/C++ Precompiled Headers settings to Not using precompiled headers for XZip.cpp and XUnzip.cpp. Be sure to do this for All Configurations.

3. When I try to build the demo app, I get the linker error LINK : fatal error LNK1104: cannot open file "mfc42u.lib" Error executing link.exe. How can I fix this?
   The default installation options of Visual C++ v6.0 don't install the Unicode libraries of MFC, so you might get an error that mfc42u.lib or mfc42ud.lib cannot be found. You can fix this either by installing the Unicode libs from the VC++ install CD, or by going to Build | Set Active Configuration and selecting one of the non-Unicode configurations.

   

   You can configure the Visual Studio toolbars to include the Select Active Configuration combobox. This allows you to see at a glance what configuration you are working with.

4. I don't need the Zip/Unzip functions. Can I exclude XZip.cpp/XUnzip.cpp?
   Yes. You only need to include the .h/.cpp pair that you need.
5. Can we use XZip in our (shareware/commercial) app?
   Yes, you can use XZip without charge or license fee, providing you follow the Info-ZIP restrictions as defined in XZip.cpp.
6. Does XZip handle pipes? in-memory zipping?
   XZip has not been tested with anything other than files.
7. Can I use XZip in a VS2005 project?
   Yes. There is a sample VS2005 project included in the download.
8. Does XZip work on Vista?
   Yes.

Acknowledgments

• The code in XZip.cpp and XUnzip.cpp is included with the kind permission of Lucian Wischik. It is based on code from Info-ZIP. Please see XZip.cpp for Info-ZIP's copyright and restrictions.
• The CXListBox class is taken from my own article, XListBox - Owner-draw CListBox with selectable text and background colors.

Revision History

Version 1.3 - 2007 July 18

• Fixed problem with file size that is multiple of 16384, reported by Mathias Svensson.
• Fixed XZip to save file time in local time, suggested by Damir Valiulin.

Version 1.2 - 2007 June 30

• Added project for VS2005.
• Added AddFolderContent() contributed by Renaud Deysine.
• Fixed problem with TUnzip::Open() reported by Pete Howells. Open() now returns correct success code.
• Fixed several bugs reported by Warren Stevens.
• Fixed a problem in unzReadCurrentFile() reported by Kochise.
• Fixed bug in EnsureDirectory() reported by craigmj.
• Changed ideflate() suggested by Michael B. Hansen.
• Fixed problem with time_t reported by Ronney.
• Fixed problems found by Boundschecker as reported by Warren Stevens.
• Made changes to PUTSHORT and PUTBYTE macros and to TZip::write(), suggested by vielheit.

Version 1.1 - 2003 May 7

• Initial public release

Usage

This software is released into the public domain. You are free to use it in any way you like, except that you may not sell this source code. If you modify it or extend it, please to consider posting new code here for everyone to share. This software is provided "as is" with no expressed or implied warranty. I accept no liability for any damage or loss of business that this software may cause.