freepascal.compiler/packages/base/paszlib

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PASZLIB 1.0 May 11th, 1998

Based on the zlib 1.1.2, a general purpose data compression library.

Copyright (C) 1998 by NOMSSI NZALI Jacques H. C.
[kn&n DES] See "Legal issues" for conditions of distribution and use.
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Introduction
============

The 'zlib' compression library provides in-memory compression and
decompression functions, including integrity checks of the uncompressed
data. This version of the library supports only one compression method
(deflation) but other algorithms will be added later and will have the same
stream interface.

Compression can be done in a single step if the buffers are large
enough (for example if an input file is mmap'ed), or can be done by
repeated calls of the compression function. In the latter case, the
application must provide more input and/or consume the output
(providing more output space) before each call.

The default memory requirements for deflate are 256K plus a few kilobytes
for small objects. The default memory requirements for inflate are 32K
plus a few kilobytes for small objects.

Change Log
==========

May 7th 1999 - Some changes for FPC
deflateCopy() has new parameters
trees.pas - record constant definition
June 17th 1998 - Applied official 1.1.2 patch.
Memcheck turned off by default.
zutil.pas patch for Delphi 1 memory allocation corrected.
dzlib.txt file added.
compress2() is now exported

June 25th 1998 - fixed a conversion bug: in inftrees.pas, ZFREE(z, v) was
missing in line 574;

File list
=========

Here is a road map to the files in the Paszlib distribution.

readme.txt Introduction, Documentation
dzlib.txt Changes to Delphi sources for Paszlib stream classes

include file

zconf.inc Configuration declarations.

Pascal source code files:

adler.pas compute the Adler-32 checksum of a data stream
crc.pas compute the CRC-32 of a data stream
gzio.pas IO on .gz files
infblock.pas interpret and process block types to last block
infcodes.pas process literals and length/distance pairs
inffast.pas process literals and length/distance pairs fast
inftrees.pas generate Huffman trees for efficient decoding
infutil.pas types and macros common to blocks and codes
minigzip.pas simulate gzip using the zlib compression library
strutils.pas string utilities
trees.pas output deflated data using Huffman coding
zcompres.pas compress a memory buffer
zdeflate.pas compress data using the deflation algorithm
zinflate.pas zlib interface to inflate modules
zlib.pas zlib data structures. read the comments there!
zuncompr.pas decompress a memory buffer
zutil.pas

Test applications

example.pas usage example of the zlib compression library
minigzip.pas simulate gzip using the zlib compression library

Legal issues
============

Copyright (C) 1998 by Jacques Nomssi Nzali

This software is provided 'as-is', without any express or implied
warranty. In no event will the author be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.


Archive Locations:
==================

Check the Paszlib home page with links

http://www.tu-chemnitz.de/~nomssi/paszlib.html

The data format used by the zlib library is described by RFCs (Request for
Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
These documents are also available in other formats from
ftp://ftp.uu.net/graphics/png/documents/zlib/zdoc-index.html.
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Jacques Nomssi Nzali May 7th, 1999