README
1ZLIB DATA COMPRESSION LIBRARY
2
3zlib 1.2.3 is a general purpose data compression library. All the code is
4thread safe. The data format used by the zlib library is described by RFCs
5(Request for Comments) 1950 to 1952 in the files
6http://www.ietf.org/rfc/rfc1950.txt (zlib format), rfc1951.txt (deflate format)
7and rfc1952.txt (gzip format). These documents are also available in other
8formats from ftp://ftp.uu.net/graphics/png/documents/zlib/zdoc-index.html
9
10All functions of the compression library are documented in the file zlib.h
11(volunteer to write man pages welcome, contact zlib@gzip.org). A usage example
12of the library is given in the file example.c which also tests that the library
13is working correctly. Another example is given in the file minigzip.c. The
14compression library itself is composed of all source files except example.c and
15minigzip.c.
16
17To compile all files and run the test program, follow the instructions given at
18the top of Makefile. In short "make test; make install" should work for most
19machines. For Unix: "./configure; make test; make install". For MSDOS, use one
20of the special makefiles such as Makefile.msc. For VMS, use make_vms.com.
21
22Questions about zlib should be sent to <zlib@gzip.org>, or to Gilles Vollant
23<info@winimage.com> for the Windows DLL version. The zlib home page is
24http://www.zlib.org or http://www.gzip.org/zlib/ Before reporting a problem,
25please check this site to verify that you have the latest version of zlib;
26otherwise get the latest version and check whether the problem still exists or
27not.
28
29PLEASE read the zlib FAQ http://www.gzip.org/zlib/zlib_faq.html before asking
30for help.
31
32Mark Nelson <markn@ieee.org> wrote an article about zlib for the Jan. 1997
33issue of Dr. Dobb's Journal; a copy of the article is available in
34http://dogma.net/markn/articles/zlibtool/zlibtool.htm
35
36The changes made in version 1.2.3 are documented in the file ChangeLog.
37
38Unsupported third party contributions are provided in directory "contrib".
39
40A Java implementation of zlib is available in the Java Development Kit
41http://java.sun.com/j2se/1.4.2/docs/api/java/util/zip/package-summary.html
42See the zlib home page http://www.zlib.org for details.
43
44A Perl interface to zlib written by Paul Marquess <pmqs@cpan.org> is in the
45CPAN (Comprehensive Perl Archive Network) sites
46http://www.cpan.org/modules/by-module/Compress/
47
48A Python interface to zlib written by A.M. Kuchling <amk@amk.ca> is
49available in Python 1.5 and later versions, see
50http://www.python.org/doc/lib/module-zlib.html
51
52A zlib binding for TCL written by Andreas Kupries <a.kupries@westend.com> is
53availlable at http://www.oche.de/~akupries/soft/trf/trf_zip.html
54
55An experimental package to read and write files in .zip format, written on top
56of zlib by Gilles Vollant <info@winimage.com>, is available in the
57contrib/minizip directory of zlib.
58
59
60Notes for some targets:
61
62- For Windows DLL versions, please see win32/DLL_FAQ.txt
63
64- For 64-bit Irix, deflate.c must be compiled without any optimization. With
65 -O, one libpng test fails. The test works in 32 bit mode (with the -n32
66 compiler flag). The compiler bug has been reported to SGI.
67
68- zlib doesn't work with gcc 2.6.3 on a DEC 3000/300LX under OSF/1 2.1 it works
69 when compiled with cc.
70
71- On Digital Unix 4.0D (formely OSF/1) on AlphaServer, the cc option -std1 is
72 necessary to get gzprintf working correctly. This is done by configure.
73
74- zlib doesn't work on HP-UX 9.05 with some versions of /bin/cc. It works with
75 other compilers. Use "make test" to check your compiler.
76
77- gzdopen is not supported on RISCOS, BEOS and by some Mac compilers.
78
79- For PalmOs, see http://palmzlib.sourceforge.net/
80
81- When building a shared, i.e. dynamic library on Mac OS X, the library must be
82 installed before testing (do "make install" before "make test"), since the
83 library location is specified in the library.
84
85
86Acknowledgments:
87
88 The deflate format used by zlib was defined by Phil Katz. The deflate
89 and zlib specifications were written by L. Peter Deutsch. Thanks to all the
90 people who reported problems and suggested various improvements in zlib;
91 they are too numerous to cite here.
92
93Copyright notice:
94
95 (C) 1995-2004 Jean-loup Gailly and Mark Adler
96
97 This software is provided 'as-is', without any express or implied
98 warranty. In no event will the authors be held liable for any damages
99 arising from the use of this software.
100
101 Permission is granted to anyone to use this software for any purpose,
102 including commercial applications, and to alter it and redistribute it
103 freely, subject to the following restrictions:
104
105 1. The origin of this software must not be misrepresented; you must not
106 claim that you wrote the original software. If you use this software
107 in a product, an acknowledgment in the product documentation would be
108 appreciated but is not required.
109 2. Altered source versions must be plainly marked as such, and must not be
110 misrepresented as being the original software.
111 3. This notice may not be removed or altered from any source distribution.
112
113 Jean-loup Gailly Mark Adler
114 jloup@gzip.org madler@alumni.caltech.edu
115
116If you use the zlib library in a product, we would appreciate *not*
117receiving lengthy legal documents to sign. The sources are provided
118for free but without warranty of any kind. The library has been
119entirely written by Jean-loup Gailly and Mark Adler; it does not
120include third-party code.
121
122If you redistribute modified sources, we would appreciate that you include
123in the file ChangeLog history information documenting your changes. Please
124read the FAQ for more information on the distribution of modified source
125versions.
126
README.rsync
1READ THIS BEFORE TRYING TO DYNAMICALLY LINK RSYNC AND ZLIB!
2
3zlib has been adapted slightly for use in rsync. Please don't bother
4the zlib authors with problems related to the use of zlib in rsync as
5any bugs are likely to be our fault and not theirs.
6
7Specific changes that have been made to zlib for rsync include:
8
9- add Z_INSERT_ONLY to allow for efficient history updating without
10 actually emitting any data. This is used to compress the matched
11 blocks that don't cross the wire, which gives better compression
12 ratios on the literal data.
13
14- fixed a number of minor compilation issues. (redefinition of MAX and
15 other such trivial things)
16
17- include rsync.h to ensure that we get a consistent set of includes
18 for all C code in rsync and to take advantage of autoconf
19
20As a result of the first item, the streams from rsync's version of
21zlib are *not compatible* with those produced by the upstream version
22of rsync. In other words, if you link rsync against your system's
23copy, it will not be able to interoperate with any other version if
24the -z option is used. (Sorry. Sometimes standard is better than
25better.)
26
27The rsync maintainers hope to fix this problem in the future by either
28merging our changes into the upstream version, or backing them out of
29rsync in a way that preserves wire compatibility. But in the meantime
30this version must be maintained in parallel.
31
32