ZLIB DATA COMPRESSION LIBRARY



zlib 1.2.3 is a general purpose data compression library.  All the code is

thread safe.  The data format used by the zlib library is described by RFCs

(Request for Comments) 1950 to 1952 in the files

http://www.ietf.org/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



All functions of the compression library are documented in the file zlib.h

(volunteer to write man pages welcome, contact zlib@gzip.org). A usage example

of the library is given in the file example.c which also tests that the library

is working correctly. Another example is given in the file minigzip.c. The

compression library itself is composed of all source files except example.c and

minigzip.c.



To compile all files and run the test program, follow the instructions given at

the top of Makefile. In short "make test; make install" should work for most

machines. For Unix: "./configure; make test; make install". For MSDOS, use one

of the special makefiles such as Makefile.msc. For VMS, use make_vms.com.



Questions about zlib should be sent to <zlib@gzip.org>, or to Gilles Vollant

<info@winimage.com> for the Windows DLL version. The zlib home page is

http://www.zlib.org or http://www.gzip.org/zlib/ Before reporting a problem,

please check this site to verify that you have the latest version of zlib;

otherwise get the latest version and check whether the problem still exists or

not.



PLEASE read the zlib FAQ http://www.gzip.org/zlib/zlib_faq.html before asking

for help.



Mark Nelson <markn@ieee.org> wrote an article about zlib for the Jan. 1997

issue of  Dr. Dobb's Journal; a copy of the article is available in

http://dogma.net/markn/articles/zlibtool/zlibtool.htm



The changes made in version 1.2.3 are documented in the file ChangeLog.



Unsupported third party contributions are provided in directory "contrib".



A Java implementation of zlib is available in the Java Development Kit

http://java.sun.com/j2se/1.4.2/docs/api/java/util/zip/package-summary.html

See the zlib home page http://www.zlib.org for details.



A Perl interface to zlib written by Paul Marquess <pmqs@cpan.org> is in the

CPAN (Comprehensive Perl Archive Network) sites

http://www.cpan.org/modules/by-module/Compress/



A Python interface to zlib written by A.M. Kuchling <amk@amk.ca> is

available in Python 1.5 and later versions, see

http://www.python.org/doc/lib/module-zlib.html



A zlib binding for TCL written by Andreas Kupries <a.kupries@westend.com> is

availlable at http://www.oche.de/~akupries/soft/trf/trf_zip.html



An experimental package to read and write files in .zip format, written on top

of zlib by Gilles Vollant <info@winimage.com>, is available in the

contrib/minizip directory of zlib.





Notes for some targets:



- For Windows DLL versions, please see win32/DLL_FAQ.txt



- For 64-bit Irix, deflate.c must be compiled without any optimization. With

  -O, one libpng test fails. The test works in 32 bit mode (with the -n32

  compiler flag). The compiler bug has been reported to SGI.



- zlib doesn't work with gcc 2.6.3 on a DEC 3000/300LX under OSF/1 2.1 it works

  when compiled with cc.



- On Digital Unix 4.0D (formely OSF/1) on AlphaServer, the cc option -std1 is

  necessary to get gzprintf working correctly. This is done by configure.



- zlib doesn't work on HP-UX 9.05 with some versions of /bin/cc. It works with

  other compilers. Use "make test" to check your compiler.



- gzdopen is not supported on RISCOS, BEOS and by some Mac compilers.



- For PalmOs, see http://palmzlib.sourceforge.net/



- When building a shared, i.e. dynamic library on Mac OS X, the library must be

  installed before testing (do "make install" before "make test"), since the

  library location is specified in the library.





Acknowledgments:



  The deflate format used by zlib was defined by Phil Katz. The deflate

  and zlib specifications were written by L. Peter Deutsch. Thanks to all the

  people who reported problems and suggested various improvements in zlib;

  they are too numerous to cite here.



Copyright notice:



 (C) 1995-2004 Jean-loup Gailly and Mark Adler



  This software is provided 'as-is', without any express or implied

  warranty.  In no event will the authors 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.



  Jean-loup Gailly        Mark Adler

  jloup@gzip.org          madler@alumni.caltech.edu



If you use the zlib library in a product, we would appreciate *not*

receiving lengthy legal documents to sign. The sources are provided

for free but without warranty of any kind.  The library has been

entirely written by Jean-loup Gailly and Mark Adler; it does not

include third-party code.



If you redistribute modified sources, we would appreciate that you include

in the file ChangeLog history information documenting your changes. Please

read the FAQ for more information on the distribution of modified source

versions.

