Скачать LZW4P - LZW Data Compression Library for Pascal

MarshallSoft Computing
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   		LZW Data Compression Library
                       For Turbo Pascal


                          Version 1.3

                         Sept 10, 1993

               This software is provided as-is.
        There are no warranties, expressed or implied.

                     Copyright (C) 1993
                     All rights reserved

                     MarshallSoft Computing, Inc.
                     Post Office Box 4543
                     Huntsville AL 35815

                     205-881-4630  Voice / FAX
                     205-880-9748  Support BBS

1.0 Introduction

LZW4P consists of a variable code size implementation of the LZW (Lempel-Ziv-Welch) algorithm for compressing and decompressing data. LZW does particularly well on text files, achieving better than a 50 % compression ratio for many files.

The LZW algorithm is considered to be one of the best general purpose algorithms available today. The new high speed modems that employ on-the-fly data compression (such as MNP 5.0 & the V.42 bis international standard) use the LZW algorithm, as well as such well known utility programs such as PKZIP.

The LZW4P library is designed to be used in a wide variety of situations. Some of the possible uses include:

  1. Compression and expanding files on disk.
  2. Compressing files "on the fly" before sending over a modem, and then expanding on the receiving end.
  3. Compression of data files used by your application program such as help files, graphics screens, etc. The compressed data files are then expanded as they are loaded by the application.

1.1 Distribution Files

The distribution files are as follows:

  1. LZW4P.DOC -- This documentation file.
  2. LZW4P.INV -- Invoice file.
  3. COMPRESS.PAS -- Data compression example program.
  4. EXPAND.PAS -- Data expansion example program.
  5. LZW4P.PAS -- Library unit interface.
  6. TEST_LZW.PAS -- LZW test driver program.
  7. MK_ARC.PAS -- File archiving program.
  8. UN_ARC.PAS -- File un-archiving program.
  9. RW_IO.PAS -- Reader/Writer I/O source file.
  10. DIR_IO.PAS -- Directory I/O source file.
  11. LZW_ERR.PAS -- Displays text error messages.
  12. MEMORY.PAS -- Memory allocation functions.
  13. HEX_IO.PAS -- Procedure to read & write hexidecimal.
  14. LZW4PLIB.OBJ -- Library object file.

Registered users also receive:

  1. LZW4PLIB.ASM -- Library source file.
  2. MAKETPU.BAT -- Makes library object from source.