zlib/README

zlib 1.0 is a general purpose data compression library.  All the code
is reentrant (thread safe).  The data format used by the zlib library
is described in the files zlib-3.3.doc, deflate-1.3.doc and
gzip-4.3.doc, available in ftp://ftp.uu.net/pub/archiving/zip/doc/

All functions of the compression library are documented in the file
zlib.h. 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 MSDOS, use one of the special
makefiles such as Makefile.msc; for VMS, use Make_vms.com or descrip.mms.

Questions about zlib should be sent to <zlib@quest.jpl.nasa.gov> or,
if this fails, to the addresses given below in the Copyright section.

The changes made in version 1.0 are documented in the file ChangeLog.
The main changes since 0.95 are:
- allow preset dictionary shared between compressor and decompressor
- allow compression level 0 (no compression)
- add deflateParams in zlib.h: allow dynamic change of compression level
  and compression strategy.
- test large buffers and deflateParams in example.c
- add optional "configure" to build zlib as a shared library
- suppress Makefile.qnx, use configure instead
- fixes for 64-bit systems (needed for Alpha and Cray)
- declare Z_DEFLATED in zlib.h (possible parameter for deflateInit2)
- always return Z_BUF_ERROR when deflate() has nothing to do
- deflateInit and inflateInit are now macros to allow version checking
- prefix all global functions and types with z_ with -DZ_PREFIX
- fix some very unlikely race conditions in multi-threaded environment
- several minor fixes for better portability
- free in reverse order of allocation to help memory manager
- use zlib-1.0/* instead of zlib/* inside the tar.gz
- make zlib warning-free with "gcc -O3 -Wall -Wwrite-strings -Wpointer-arith
  -Wconversion -Wstrict-prototypes -Wmissing-prototypes"
- allow gzread on concatenated .gz files
- deflateEnd now returns Z_DATA_ERROR if it was premature
- deflate is finally (?) fully deterministic

Notes for some targets:

- For Turbo C the small model is supported only with reduced performance to
  avoid any far allocation; it was tested with -DMAX_WBITS=11 -DMAX_MEM_LEVEL=3

- For 64-bit Iris, deflate.c must be compiled without any optimization.
  With -O, one libpng test fails. The test works in 32 bit mode (with the
  -32 compiler flag).

- 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.

- zlib doesn't work on HP-UX 9.05 with one cc compiler (the one not
  accepting the -O option). It works with the other cc compiler.

A Perl interface to zlib written by Paul Marquess <pmarquess@bfsec.bt.co.uk>
is in the CPAN (Comprehensive Perl Archive Network) sites, such as:
ftp://ftp.cis.ufl.edu/pub/perl/CPAN/modules/by-module/Compress/Compress-Zlib*

Acknowledgments:

  The deflate format used by zlib was defined by Phil Katz. The deflate
  and zlib specifications were written by 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) 1995-1996 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
  gzip@prep.ai.mit.edu    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.