/* inflate.h -- internal inflate state definition * Copyright (C) 1995-2016 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */ /* WARNING: this file should *not* be used by applications. It is part of the implementation of the compression library and is subject to change. Applications should only use zlib.h. */ /* define NO_GZIP when compiling if you want to disable gzip header and trailer decoding by inflate(). NO_GZIP would be used to avoid linking in the crc code when it is not needed. For shared libraries, gzip decoding should be left enabled. */ #ifndef NO_GZIP # define GUNZIP #endif /* Possible inflate modes between inflate() calls */ typedef enum { HEAD = 16180, /* i: waiting for magic header */ FLAGS, /* i: waiting for method and flags (gzip) */ TIME, /* i: waiting for modification time (gzip) */ OS, /* i: waiting for extra flags and operating system (gzip) */ EXLEN, /* i: waiting for extra length (gzip) */ EXTRA, /* i: waiting for extra bytes (gzip) */ NAME, /* i: waiting for end of file name (gzip) */ COMMENT, /* i: waiting for end of comment (gzip) */ HCRC, /* i: waiting for header crc (gzip) */ DICTID, /* i: waiting for dictionary check value */ DICT, /* waiting for inflateSetDictionary() call */ TYPE, /* i: waiting for type bits, including last-flag bit */ TYPEDO, /* i: same, but skip check to exit inflate on new block */ STORED, /* i: waiting for stored size (length and complement) */ COPY_, /* i/o: same as COPY below, but only first time in */ COPY, /* i/o: waiting for input or output to copy stored block */ TABLE, /* i: waiting for dynamic block table lengths */ LENLENS, /* i: waiting for code length code lengths */ CODELENS, /* i: waiting for length/lit and distance code lengths */ LEN_, /* i: same as LEN below, but only first time in */ LEN, /* i: waiting for length/lit/eob code */ LENEXT, /* i: waiting for length extra bits */ DIST, /* i: waiting for distance code */ DISTEXT, /* i: waiting for distance extra bits */ MATCH, /* o: waiting for output space to copy string */ LIT, /* o: waiting for output space to write literal */ CHECK, /* i: waiting for 32-bit check value */ LENGTH, /* i: waiting for 32-bit length (gzip) */ DONE, /* finished check, done -- remain here until reset */ BAD, /* got a data error -- remain here until reset */ MEM, /* got an inflate() memory error -- remain here until reset */ SYNC /* looking for synchronization bytes to restart inflate() */ } inflate_mode; /* State transitions between above modes - (most modes can go to BAD or MEM on error -- not shown for clarity) Process header: HEAD -> (gzip) or (zlib) or (raw) (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT -> HCRC -> TYPE (zlib) -> DICTID or TYPE DICTID -> DICT -> TYPE (raw) -> TYPEDO Read deflate blocks: TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK STORED -> COPY_ -> COPY -> TYPE TABLE -> LENLENS -> CODELENS -> LEN_ LEN_ -> LEN Read deflate codes in fixed or dynamic block: LEN -> LENEXT or LIT or TYPE LENEXT -> DIST -> DISTEXT -> MATCH -> LEN LIT -> LEN Process trailer: CHECK -> LENGTH -> DONE */ /* State maintained between inflate() calls -- approximately 7K bytes, not including the allocated sliding window, which is up to 32K bytes. */ struct inflate_state { z_streamp strm; /* pointer back to this zlib stream */ inflate_mode mode; /* current inflate mode */ int last; /* true if processing last block */ int wrap; /* bit 0 true for zlib, bit 1 true for gzip, bit 2 true to validate check value */ int havedict; /* true if dictionary provided */ int flags; /* gzip header method and flags (0 if zlib) */ unsigned dmax; /* zlib header max distance (INFLATE_STRICT) */ unsigned long check; /* protected copy of check value */ unsigned long total; /* protected copy of output count */ gz_headerp head; /* where to save gzip header information */ /* sliding window */ unsigned wbits; /* log base 2 of requested window size */ unsigned wsize; /* window size or zero if not using window */ unsigned whave; /* valid bytes in the window */ unsigned wnext; /* window write index */ unsigned char FAR *window; /* allocated sliding window, if needed */ /* bit accumulator */ unsigned long hold; /* input bit accumulator */ unsigned bits; /* number of bits in "in" */ /* for string and stored block copying */ unsigned length; /* literal or length of data to copy */ unsigned offset; /* distance back to copy string from */ /* for table and code decoding */ unsigned extra; /* extra bits needed */ /* fixed and dynamic code tables */ code const FAR *lencode; /* starting table for length/literal codes */ code const FAR *distcode; /* starting table for distance codes */ unsigned lenbits; /* index bits for lencode */ unsigned distbits; /* index bits for distcode */ /* dynamic table building */ unsigned ncode; /* number of code length code lengths */ unsigned nlen; /* number of length code lengths */ unsigned ndist; /* number of distance code lengths */ unsigned have; /* number of code lengths in lens[] */ code FAR *next; /* next available space in codes[] */ unsigned short lens[320]; /* temporary storage for code lengths */ unsigned short work[288]; /* work area for code table building */ code codes[ENOUGH]; /* space for code tables */ int sane; /* if false, allow invalid distance too far */ int back; /* bits back of last unprocessed length/lit */ unsigned was; /* initial length of match */ }; a> 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115
ZLIB DATA COMPRESSION LIBRARY
zlib 1.2.11 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://tools.ietf.org/html/rfc1950 (zlib format), rfc1951 (deflate format) and
rfc1952 (gzip format).
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 test/example.c which also tests that
the library is working correctly. Another example is given in the file
test/minigzip.c. The compression library itself is composed of all source
files in the root directory.
To compile all files and run the test program, follow the instructions given at
the top of Makefile.in. In short "./configure; make test", and if that goes
well, "make install" should work for most flavors of Unix. For Windows, use
one of the special makefiles in win32/ or contrib/vstudio/ . 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://zlib.net/ . 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://zlib.net/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 at
http://marknelson.us/1997/01/01/zlib-engine/ .
The changes made in version 1.2.11 are documented in the file ChangeLog.
Unsupported third party contributions are provided in directory contrib/ .
zlib is available in Java using the java.util.zip package, documented at
http://java.sun.com/developer/technicalArticles/Programming/compression/ .
A Perl interface to zlib written by Paul Marquess <pmqs@cpan.org> is available
at CPAN (Comprehensive Perl Archive Network) sites, including
http://search.cpan.org/~pmqs/IO-Compress-Zlib/ .
A Python interface to zlib written by A.M. Kuchling <amk@amk.ca> is
available in Python 1.5 and later versions, see
http://docs.python.org/library/zlib.html .
zlib is built into tcl: http://wiki.tcl.tk/4610 .
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 or BEOS.
- For PalmOs, see http://palmzlib.sourceforge.net/
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) 1995-2017 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.