ActiveX technology

• A single fully self-contained COM object and ActiveX control written with ATL 3.0.
• Requires no external compression DLLs, MFC DLLs, or runtime libraries.
• Both single-threaded (STA) and multi-threaded apartment (MTA) model design.
• Instantiate the component dynamically without putting it on a form.
• Supports multiple instances running simultaneously.
• Supports both Unicode and ANSI in one single control. The library automatically uses Unicode API calls for best performance when rugnning on Windows NT, 2000, and XP.
• ActiveX control interface has all constants, enumerations, and types built-in. Code completion, property categories, help strings, and context-sensitive F1-help fully supported.
• Works with all 32-bit development environments that can use ActiveX controls, including VB, VC++, Delphi, C++ Builder, VFP, Office, PB, VO, Web scripting languages, ASP, and DCOM projects.
• Also compatible with VB.NET and C#. For developers that require 100% managed code, check out Xceed Zip for .NET, our fully object-oriented Zip, compression and FileSystem class library.

Compression & Zip file technology

• Supports WinZip 9.0 (and up) compatible AES strong encryption.
• Fast, low memory usage compression engine.
• 100% compatible with the PKZIP 2.04g format.
• 100% compatible with the PKZIP 4.5 format.
• Supports the Zip64 zip file format allowing the creation of Zip files of practically unlimited size (no 4 GB limit).
• Supports the BZip2 (BWT) compression method for 15% to 20% better compression than Deflate on many popular file types, especially XML data.
• The only library to provide WinZip 12 compatibility, supporting the LZMA algorithm for improved compression in certain situations. Note: Zip files using WinZip 12’s special JPEG recompression feature are not supported.
• UTF-8 character encoding in headers for improved support of international characters in filenames and comments is provided.
• Supports the Deflate64TM compression method, an industry standard improvement to regular Deflate.
• Zip files can contain any number of files (no 65535 file limit).
• Regular, spanned, and self-extracting zip files created by Xceed Zip can be used by any of today's existing unzipping applications, and vice-versa.
• Stores and retrieves the latest zip file format extensions, allowing Unicode filenames and NT file attributes, extra time stamps, and security permissions to be stored in the zip file.
• No need to repair corrupted zip files. Xceed Zip automatically tries to recover from errors and reports any inconsistencies found in the zip file while unzipping.

Major operations

• Zip files or memory buffers into new or existing zip files.
• Unzip files to disk or directly to memory.
• Compress and decompress strings or buffers completely in memory.
• All compression and decompression modes support streaming and encryption.
• Create fully customizable self-extracting zip files (see section below for features)
• Convert any type of zip file (regular, spanned, multi-part, self-extracting, or spanned self-extracting) into any other type of zip file.
• Reads and writes zip files that span multiple disks.
• Reads and writes multi-part zip files directly to hard drive.
• Update one zip file from another one's contents or merge two zip files together.
• Optional background processing so your code can continue execution while Xceed Zip is working.

Application-component interactivity

• All operations can be aborted at any time.
• Provides status report events on a file-by-file basis as well as on the entire operation being performed, with percentages, byte, and file counts. Easily add any kind of progress bar to your apps.
• Events are triggered whenever a file is being zipped, unzipped, updated, deleted, etc.
• Notifies your application when and why a specific file cannot be processed.
• Notifies your application when a file being zipped or unzipped is about to overwrite an existing file. Your application can then choose to overwrite it or skip it. You can also rename files.
• Provides complete file information for the file currently being processed.
• Your application receives info such as a file's achieved compression ratio, compressed size, and other info as it becomes available.
• Informs your application that it should prompt the user to insert a specific disk when reading or writing zip files that span multiple disks.
• Many events have modifiable parameters to allow your application to change file parameters or specifications as the files are being zipped, unzipped, converted, etc.
• Unused events can be prevented from being triggered for increased performance.
• Provide feedback to the user when the temporary zip file is being copied to its final destination.
• Provide feedback to the user when the zip file's central directory is being written.

Zip file manipulation functionality

• Obtain global information on a zip file.
• Obtain a detailed list of a zip file's contents via a collection object.
• Obtain a detailed list of a zip file's contents via events.
• Delete files from within a zip file.
• Delete files after they have been successfully and verifiably zipped.
• Test the integrity of a zip file and its contents.
• Process or exclude files based on file attributes, sizes, version resources and dates, or create your own custom include/exclude filters.
• Wildcard previewing: find out exactly which files will match your wildcards and filters before you start zipping or unzipping.
• Compression previewing: obtain the compressed file sizes before starting the actual zipping operation. Statistics on the entire group of files to be zipped are also provided.
• Add and retrieve comments for individual files in the zip file.
• Get and set the global zip file comment.
• Automatic full yield so other applications do not halt during processing.
• Clear disks before writing the zip file to them.
• Specify the amount of free space to leave on the first disk of a spanned zip file set.
• Reject disks without specified amount of free space on them when spanning.

Direct DLL API access

• The library's single DLL can also be accessed as a standard 32-bit DLL through its exported API.
• All properties, methods, and events are exported.
• All exported API calls involving string parameters come in single, wide character, and Unicode versions.
• Events can be handled either by callback functions or by windows messages.