143 lines
6.9 KiB
Text
143 lines
6.9 KiB
Text
zlib 1.1.2 is a general purpose data compression library. All the code
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is thread safe. The data format used by the zlib library
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is described by RFCs (Request for Comments) 1950 to 1952 in the files
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ftp://ds.internic.net/rfc/rfc1950.txt (zlib format), rfc1951.txt (deflate
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format) and rfc1952.txt (gzip format). These documents are also available in
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other formats from ftp://ftp.uu.net/graphics/png/documents/zlib/zdoc-index.html
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All functions of the compression library are documented in the file zlib.h
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(volunteer to write man pages welcome, contact jloup@gzip.org). A usage
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example of the library is given in the file example.c which also tests that
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the library is working correctly. Another example is given in the file
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minigzip.c. The compression library itself is composed of all source files
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except example.c and minigzip.c.
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To compile all files and run the test program, follow the instructions
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given at the top of Makefile. In short "make test; make install"
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should work for most machines. For MSDOS, use one of the special
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makefiles such as Makefile.msc; for VMS, use Make_vms.com or descrip.mms.
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Questions about zlib should be sent to <zlib@quest.jpl.nasa.gov> or,
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if this fails, to the addresses given below in the Copyright section.
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The zlib home page is http://www.cdrom.com/pub/infozip/zlib/
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The official zlib ftp site is ftp://ftp.cdrom.com/pub/infozip/zlib/
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Mark Nelson <markn@tiny.com> wrote an article about zlib for the Jan. 1997
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issue of Dr. Dobb's Journal; a copy of the article is available in
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http://web2.airmail.net/markn/articles/zlibtool/zlibtool.htm
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The changes made in version 1.1.2 are documented in the file ChangeLog.
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The main changes since 1.1.1 are:
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- added contrib/minzip, mini zip and unzip based on zlib (Gilles Vollant)
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See http://www.winimage.com/zLibDll/unzip.html
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- preinitialize the inflate tables for fixed codes, to make the code
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completely thread safe (Mark)
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- some simplifications and slight speed-up to the inflate code (Mark)
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- fix gzeof on non-compressed files (Allan Schrum)
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- add -std1 option in configure for OSF1 to fix gzprintf (Martin Mokrejs)
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- use default value of 4K for Z_BUFSIZE for 16-bit MSDOS (Tim Wegner + Glenn)
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- added os2/Makefile.def and os2/zlib.def (Andrew Zabolotny)
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- add shared lib support for UNIX_SV4.2MP (MATSUURA Takanori)
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- do not wrap extern "C" around system includes (Tom Lane)
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- added amiga/Makefile.pup for Amiga powerUP SAS/C PPC (Andreas Kleinert)
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- allow "make install prefix=..." even after configure (Glenn Randers-Pehrson)
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- allow "configure --prefix $HOME" (Tim Mooney)
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Unsupported third party contributions are provided in directory "contrib".
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A Java implementation of zlib is available in the Java Development Kit 1.1
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http://www.javasoft.com/products/JDK/1.1/docs/api/Package-java.util.zip.html
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See the zlib home page http://www.cdrom.com/pub/infozip/zlib/ for details.
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A Perl interface to zlib written by Paul Marquess <pmarquess@bfsec.bt.co.uk>
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is in the CPAN (Comprehensive Perl Archive Network) sites, such as:
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ftp://ftp.cis.ufl.edu/pub/perl/CPAN/modules/by-module/Compress/Compress-Zlib*
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A Python interface to zlib written by A.M. Kuchling <amk@magnet.com>
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is available from the Python Software Association sites, such as:
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ftp://ftp.python.org/pub/python/contrib/Encoding/zlib*.tar.gz
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A zlib binding for TCL written by Andreas Kupries <a.kupries@westend.com>
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is availlable at http://www.westend.com/~kupries/doc/trf/man/man.html
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An experimental package to read and write files in .zip format,
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written on top of zlib by Gilles Vollant <info@winimage.com>, is
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available at http://www.winimage.com/zLibDll/unzip.html
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and also in the contrib/minizip directory of zlib.
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Notes for some targets:
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- To build a Windows DLL version, include in a DLL project zlib.def, zlib.rc
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and all .c files except example.c and minigzip.c; compile with -DZLIB_DLL
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The zlib DLL support was initially done by Alessandro Iacopetti and is
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now maintained by Gilles Vollant <info@winimage.com>. Check the zlib DLL
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home page at http://www.winimage.com/zLibDll
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From Visual Basic, you can call the DLL functions which do not take
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a structure as argument: compress, uncompress and all gz* functions.
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See contrib/visual-basic.txt for more information.
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I don't know how to handle structures in Visual Basic, sorry.
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- For 64-bit Irix, deflate.c must be compiled without any optimization.
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With -O, one libpng test fails. The test works in 32 bit mode (with
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the -n32 compiler flag). The compiler bug has been reported to SGI.
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- zlib doesn't work with gcc 2.6.3 on a DEC 3000/300LX under OSF/1 2.1
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it works when compiled with cc.
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- on Digital Unix 4.0D (formely OSF/1) on AlphaServer, the cc option -std1
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is necessary to get gzprintf working correctly. This is done by configure.
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- zlib doesn't work on HP-UX 9.05 with some versions of /bin/cc. It works
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with other compilers. Use "make test" to check your compiler.
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- For shared memory multiprocessors, the decompression code assumes that
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writes to pointers are atomic. Also the functions zalloc and zfree passed
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to deflateInit must be multi-threaded in this case.
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- gzdopen is not supported on RISCOS, BEOS and by some Mac compilers.
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- For Turbo C the small model is supported only with reduced performance to
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avoid any far allocation; it was tested with -DMAX_WBITS=11 -DMAX_MEM_LEVEL=3
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Acknowledgments:
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The deflate format used by zlib was defined by Phil Katz. The deflate
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and zlib specifications were written by L. Peter Deutsch. Thanks to all the
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people who reported problems and suggested various improvements in zlib;
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they are too numerous to cite here.
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Copyright notice:
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(C) 1995-1998 Jean-loup Gailly and Mark Adler
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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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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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1. 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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2. 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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3. This notice may not be removed or altered from any source distribution.
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Jean-loup Gailly Mark Adler
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jloup@gzip.org madler@alumni.caltech.edu
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If you use the zlib library in a product, we would appreciate *not*
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receiving lengthy legal documents to sign. The sources are provided
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for free but without warranty of any kind. The library has been
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entirely written by Jean-loup Gailly and Mark Adler; it does not
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include third-party code.
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If you redistribute modified sources, we would appreciate that you include
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in the file ChangeLog history information documenting your changes.
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