2025-07-27 18:51:52 -04:00
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.TH ZLIB 3 "22 Jan 2024"
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2021-05-28 16:25:55 -04:00
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.SH NAME
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zlib \- compression/decompression library
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.SH SYNOPSIS
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[see
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.I zlib.h
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for full description]
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.SH DESCRIPTION
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The
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.I zlib
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library is a general purpose data compression library.
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The code is thread safe, assuming that the standard library functions
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used are thread safe, such as memory allocation routines.
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It provides in-memory compression and decompression functions,
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including integrity checks of the uncompressed data.
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This version of the library supports only one compression method (deflation)
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but other algorithms may be added later
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with the same stream interface.
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.LP
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Compression can be done in a single step if the buffers are large enough
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or can be done by repeated calls of the compression function.
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In the latter case,
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the application must provide more input and/or consume the output
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(providing more output space) before each call.
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.LP
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The library also supports reading and writing files in
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.IR gzip (1)
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(.gz) format
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with an interface similar to that of stdio.
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.LP
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The library does not install any signal handler.
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The decoder checks the consistency of the compressed data,
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so the library should never crash even in the case of corrupted input.
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.LP
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All functions of the compression library are documented in the file
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.IR zlib.h .
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The distribution source includes examples of use of the library
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in the files
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.I test/example.c
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and
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.IR test/minigzip.c,
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as well as other examples in the
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.IR examples/
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directory.
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.LP
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Changes to this version are documented in the file
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.I ChangeLog
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that accompanies the source.
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.LP
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.I zlib
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is built in to many languages and operating systems, including but not limited to
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Java, Python, .NET, PHP, Perl, Ruby, Swift, and Go.
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.LP
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An experimental package to read and write files in the .zip format,
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written on top of
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.I zlib
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by Gilles Vollant (info@winimage.com),
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is available at:
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.IP
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http://www.winimage.com/zLibDll/minizip.html
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and also in the
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.I contrib/minizip
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directory of the main
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.I zlib
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source distribution.
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.SH "SEE ALSO"
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The
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.I zlib
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web site can be found at:
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.IP
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http://zlib.net/
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.LP
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The data format used by the
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.I zlib
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library is described by RFC
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(Request for Comments) 1950 to 1952 in the files:
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.IP
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http://tools.ietf.org/html/rfc1950 (for the zlib header and trailer format)
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.br
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http://tools.ietf.org/html/rfc1951 (for the deflate compressed data format)
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.br
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http://tools.ietf.org/html/rfc1952 (for the gzip header and trailer format)
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.LP
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Mark Nelson wrote an article about
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.I zlib
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for the Jan. 1997 issue of Dr. Dobb's Journal;
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a copy of the article is available at:
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.IP
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http://marknelson.us/1997/01/01/zlib-engine/
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.SH "REPORTING PROBLEMS"
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Before reporting a problem,
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please check the
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.I zlib
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web site to verify that you have the latest version of
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.IR zlib ;
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otherwise,
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obtain the latest version and see if the problem still exists.
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Please read the
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.I zlib
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FAQ at:
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.IP
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http://zlib.net/zlib_faq.html
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.LP
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before asking for help.
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Send questions and/or comments to zlib@gzip.org,
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or (for the Windows DLL version) to Gilles Vollant (info@winimage.com).
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.SH AUTHORS AND LICENSE
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2025-07-27 18:51:52 -04:00
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Version 1.3.1
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2021-05-28 16:25:55 -04:00
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.LP
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2025-07-27 18:51:52 -04:00
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Copyright (C) 1995-2024 Jean-loup Gailly and Mark Adler
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2021-05-28 16:25:55 -04:00
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.LP
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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.LP
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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.LP
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.nr step 1 1
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.IP \n[step]. 3
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The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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.IP \n+[step].
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Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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.IP \n+[step].
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This notice may not be removed or altered from any source distribution.
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.LP
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Jean-loup Gailly Mark Adler
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.br
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jloup@gzip.org madler@alumni.caltech.edu
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.LP
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The deflate format used by
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.I zlib
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was defined by Phil Katz.
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The deflate and
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.I zlib
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specifications were written by L. Peter Deutsch.
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Thanks to all the people who reported problems and suggested various
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improvements in
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.IR zlib ;
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who are too numerous to cite here.
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.LP
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UNIX manual page by R. P. C. Rodgers,
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U.S. National Library of Medicine (rodgers@nlm.nih.gov).
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.\" end of man page
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