Routines to Compress and Decompress Data

The Compression Workshop is a collection of subroutines and functions for compressing and decompressing array, string, file, and video memory data. Several complete programs are provided, including a full-featured Install utility you can use to distribute your own applications in compressed form, and also a disk backup and restore program that can be added to your programs or used stand-alone.

The compression and decompression routines are designed for use with arrays, strings, and files. Numeric, TYPE, and fixed-length string arrays may be stored in compressed form on disk, either individually or in groups within a single file. One or more program or data files may also be combined into a single compressed file. Arrays may be compressed either in place (within memory) or stored in a disk file. When storing an array in a file, you indicate if the file is to be created, or if the array is to be added to an existing compressed file. Likewise, array data may be decompressed in place or read from disk. When compressing an array in memory, the compressed data replaces the original array contents, and the array is redimensioned to the new, smaller size automatically.

Separate routines are provided to manipulate data in memory and on disk. Individual strings may be compressed and decompressed in place only, and the result is assigned to the same string. Video memory may be copied to an array using supplied routines and then compressed and optionally stored on disk. A compressed file that holds other files (not one that holds arrays) may optionally be converted to a self-extracting .EXE program that unpacks itself when run, placing all of the files it contains into the current directory or any specified directory.

Finally, several complete demonstration programs are provided to show how the various Compression Workshop routines are used. These include utilities for compressing and decompressing groups of files based on command line options; an Install program that supports multiple distribution disks with separate target paths for all the files within each compressed file; and a stand-alone hard disk backup program that also shows how the backup and restore routines are added to your own programs. The backup and restore routines feature automatic disk formatting, volume labeling, traversing nested subdirectory levels, and they can optionally manipulate each file's archive bit. They can also automatically detect when a disk is changed, making them very easy for your customers to use.

As with all our products, full source code is provided at no additional cost, so you can see how the routines were designed and even modify them if you want. We genuinely want you to understand how our libraries work and be able to learn from them. All of our products are reasonably priced and include free technical assistance, but they are licensed for use by only one person using one computer at a time. Royalty payments are not required when our routines are incorporated into your compiled applications. However, you may not distribute our source, object, or library files. If your customers need to rebuild your program, they will need their own copy of our product(s).

The Compression Workshop costs $149 and works with QuickBASIC 4.x, PDS 7.x, and VB/DOS. Add $8 for UPS ground shipping to US addresses only (no P.O. boxes); Connecticut residents must add 6.0% sales tax or show proof of tax-exempt status when ordering. Please email or call for overnight and foreign shipping costs. We accept only prepaid orders accompanied by a check.

Compression Workshop is a trademark of Crescent Software, Inc.