The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/net/zlib.h

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    1 /* $FreeBSD$    */
    2 
    3 /*
    4  * This file is derived from zlib.h and zconf.h from the zlib-1.0.4
    5  * distribution by Jean-loup Gailly and Mark Adler, with some additions
    6  * by Paul Mackerras to aid in implementing Deflate compression and
    7  * decompression for PPP packets.
    8  */
    9 
   10 /*
   11  *  ==FILEVERSION 971127==
   12  *
   13  * This marker is used by the Linux installation script to determine
   14  * whether an up-to-date version of this file is already installed.
   15  */
   16 
   17 
   18 /* +++ zlib.h */
   19 /*-
   20   zlib.h -- interface of the 'zlib' general purpose compression library
   21   version 1.0.4, Jul 24th, 1996.
   22 
   23   Copyright (C) 1995-1996 Jean-loup Gailly and Mark Adler
   24 
   25   This software is provided 'as-is', without any express or implied
   26   warranty.  In no event will the authors be held liable for any damages
   27   arising from the use of this software.
   28 
   29   Permission is granted to anyone to use this software for any purpose,
   30   including commercial applications, and to alter it and redistribute it
   31   freely, subject to the following restrictions:
   32 
   33   1. The origin of this software must not be misrepresented; you must not
   34      claim that you wrote the original software. If you use this software
   35      in a product, an acknowledgment in the product documentation would be
   36      appreciated but is not required.
   37   2. Altered source versions must be plainly marked as such, and must not be
   38      misrepresented as being the original software.
   39   3. This notice may not be removed or altered from any source distribution.
   40 
   41   Jean-loup Gailly        Mark Adler
   42   gzip@prep.ai.mit.edu    madler@alumni.caltech.edu
   43 */
   44 /*
   45   The data format used by the zlib library is described by RFCs (Request for
   46   Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
   47   (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
   48 */
   49 
   50 #ifndef _ZLIB_H
   51 #define _ZLIB_H
   52 
   53 #ifdef __cplusplus
   54 extern "C" {
   55 #endif
   56 
   57 
   58 /* +++ zconf.h */
   59 /* zconf.h -- configuration of the zlib compression library
   60  * Copyright (C) 1995-1996 Jean-loup Gailly.
   61  * For conditions of distribution and use, see copyright notice in zlib.h 
   62  */
   63 
   64 /* From: zconf.h,v 1.20 1996/07/02 15:09:28 me Exp $ */
   65 
   66 #ifndef _ZCONF_H
   67 #define _ZCONF_H
   68 
   69 /*
   70  * If you *really* need a unique prefix for all types and library functions,
   71  * compile with -DZ_PREFIX. The "standard" zlib should be compiled without it.
   72  */
   73 #ifdef Z_PREFIX
   74 #  define deflateInit_  z_deflateInit_
   75 #  define deflate       z_deflate
   76 #  define deflateEnd    z_deflateEnd
   77 #  define inflateInit_  z_inflateInit_
   78 #  define inflate       z_inflate
   79 #  define inflateEnd    z_inflateEnd
   80 #  define deflateInit2_ z_deflateInit2_
   81 #  define deflateSetDictionary z_deflateSetDictionary
   82 #  define deflateCopy   z_deflateCopy
   83 #  define deflateReset  z_deflateReset
   84 #  define deflateParams z_deflateParams
   85 #  define inflateInit2_ z_inflateInit2_
   86 #  define inflateSetDictionary z_inflateSetDictionary
   87 #  define inflateSync   z_inflateSync
   88 #  define inflateReset  z_inflateReset
   89 #  define compress      z_compress
   90 #  define uncompress    z_uncompress
   91 #  define adler32       z_adler32
   92 #if 0
   93 #  define crc32         z_crc32
   94 #  define get_crc_table z_get_crc_table
   95 #endif
   96 
   97 #  define Byte          z_Byte
   98 #  define uInt          z_uInt
   99 #  define uLong         z_uLong
  100 #  define Bytef         z_Bytef
  101 #  define charf         z_charf
  102 #  define intf          z_intf
  103 #  define uIntf         z_uIntf
  104 #  define uLongf        z_uLongf
  105 #  define voidpf        z_voidpf
  106 #  define voidp         z_voidp
  107 #endif
  108 
  109 #if (defined(_WIN32) || defined(__WIN32__)) && !defined(WIN32)
  110 #  define WIN32
  111 #endif
  112 #if defined(__GNUC__) || defined(WIN32) || defined(__386__) || defined(i386)
  113 #  ifndef __32BIT__
  114 #    define __32BIT__
  115 #  endif
  116 #endif
  117 #if defined(__MSDOS__) && !defined(MSDOS)
  118 #  define MSDOS
  119 #endif
  120 
  121 /*
  122  * Compile with -DMAXSEG_64K if the alloc function cannot allocate more
  123  * than 64k bytes at a time (needed on systems with 16-bit int).
  124  */
  125 #if defined(MSDOS) && !defined(__32BIT__)
  126 #  define MAXSEG_64K
  127 #endif
  128 #ifdef MSDOS
  129 #  define UNALIGNED_OK
  130 #endif
  131 
  132 #if (defined(MSDOS) || defined(_WINDOWS) || defined(WIN32))  && !defined(STDC)
  133 #  define STDC
  134 #endif
  135 #if (defined(__STDC__) || defined(__cplusplus)) && !defined(STDC)
  136 #  define STDC
  137 #endif
  138 
  139 #ifndef STDC
  140 #  ifndef const /* cannot use !defined(STDC) && !defined(const) on Mac */
  141 #    define const
  142 #  endif
  143 #endif
  144 
  145 /* Some Mac compilers merge all .h files incorrectly: */
  146 #if defined(__MWERKS__) || defined(applec) ||defined(THINK_C) ||defined(__SC__)
  147 #  define NO_DUMMY_DECL
  148 #endif
  149 
  150 /* Maximum value for memLevel in deflateInit2 */
  151 #ifndef MAX_MEM_LEVEL
  152 #  ifdef MAXSEG_64K
  153 #    define MAX_MEM_LEVEL 8
  154 #  else
  155 #    define MAX_MEM_LEVEL 9
  156 #  endif
  157 #endif
  158 
  159 /* Maximum value for windowBits in deflateInit2 and inflateInit2 */
  160 #ifndef MAX_WBITS
  161 #  define MAX_WBITS   15 /* 32K LZ77 window */
  162 #endif
  163 
  164 /* The memory requirements for deflate are (in bytes):
  165             1 << (windowBits+2)   +  1 << (memLevel+9)
  166  that is: 128K for windowBits=15  +  128K for memLevel = 8  (default values)
  167  plus a few kilobytes for small objects. For example, if you want to reduce
  168  the default memory requirements from 256K to 128K, compile with
  169      make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
  170  Of course this will generally degrade compression (there's no free lunch).
  171 
  172    The memory requirements for inflate are (in bytes) 1 << windowBits
  173  that is, 32K for windowBits=15 (default value) plus a few kilobytes
  174  for small objects.
  175 */
  176 
  177                         /* Type declarations */
  178 
  179 #ifndef OF /* function prototypes */
  180 #  ifdef STDC
  181 #    define OF(args)  args
  182 #  else
  183 #    define OF(args)  ()
  184 #  endif
  185 #endif
  186 
  187 /* The following definitions for FAR are needed only for MSDOS mixed
  188  * model programming (small or medium model with some far allocations).
  189  * This was tested only with MSC; for other MSDOS compilers you may have
  190  * to define NO_MEMCPY in zutil.h.  If you don't need the mixed model,
  191  * just define FAR to be empty.
  192  */
  193 #if (defined(M_I86SM) || defined(M_I86MM)) && !defined(__32BIT__)
  194    /* MSC small or medium model */
  195 #  define SMALL_MEDIUM
  196 #  ifdef _MSC_VER
  197 #    define FAR __far
  198 #  else
  199 #    define FAR far
  200 #  endif
  201 #endif
  202 #if defined(__BORLANDC__) && (defined(__SMALL__) || defined(__MEDIUM__))
  203 #  ifndef __32BIT__
  204 #    define SMALL_MEDIUM
  205 #    define FAR __far
  206 #  endif
  207 #endif
  208 #ifndef FAR
  209 #   define FAR
  210 #endif
  211 
  212 typedef unsigned char  Byte;  /* 8 bits */
  213 typedef unsigned int   uInt;  /* 16 bits or more */
  214 typedef unsigned long  uLong; /* 32 bits or more */
  215 
  216 #if defined(__BORLANDC__) && defined(SMALL_MEDIUM)
  217    /* Borland C/C++ ignores FAR inside typedef */
  218 #  define Bytef Byte FAR
  219 #else
  220    typedef Byte  FAR Bytef;
  221 #endif
  222 typedef char  FAR charf;
  223 typedef int   FAR intf;
  224 typedef uInt  FAR uIntf;
  225 typedef uLong FAR uLongf;
  226 
  227 #ifdef STDC
  228    typedef void FAR *voidpf;
  229    typedef void     *voidp;
  230 #else
  231    typedef Byte FAR *voidpf;
  232    typedef Byte     *voidp;
  233 #endif
  234 
  235 
  236 /* Compile with -DZLIB_DLL for Windows DLL support */
  237 #if (defined(_WINDOWS) || defined(WINDOWS)) && defined(ZLIB_DLL)
  238 #  include <windows.h>
  239 #  define EXPORT  WINAPI
  240 #else
  241 #  define EXPORT
  242 #endif
  243 
  244 #endif /* _ZCONF_H */
  245 /* --- zconf.h */
  246 
  247 #define ZLIB_VERSION "1.0.4P"
  248 
  249 /* 
  250      The 'zlib' compression library provides in-memory compression and
  251   decompression functions, including integrity checks of the uncompressed
  252   data.  This version of the library supports only one compression method
  253   (deflation) but other algorithms may be added later and will have the same
  254   stream interface.
  255 
  256      For compression the application must provide the output buffer and
  257   may optionally provide the input buffer for optimization. For decompression,
  258   the application must provide the input buffer and may optionally provide
  259   the output buffer for optimization.
  260 
  261      Compression can be done in a single step if the buffers are large
  262   enough (for example if an input file is mmap'ed), or can be done by
  263   repeated calls of the compression function.  In the latter case, the
  264   application must provide more input and/or consume the output
  265   (providing more output space) before each call.
  266 
  267      The library does not install any signal handler. It is recommended to
  268   add at least a handler for SIGSEGV when decompressing; the library checks
  269   the consistency of the input data whenever possible but may go nuts
  270   for some forms of corrupted input.
  271 */
  272 
  273 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
  274 typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
  275 
  276 struct internal_state;
  277 
  278 typedef struct z_stream_s {
  279     Bytef    *next_in;  /* next input byte */
  280     uInt     avail_in;  /* number of bytes available at next_in */
  281     uLong    total_in;  /* total nb of input bytes read so far */
  282 
  283     Bytef    *next_out; /* next output byte should be put there */
  284     uInt     avail_out; /* remaining free space at next_out */
  285     uLong    total_out; /* total nb of bytes output so far */
  286 
  287     const char     *msg; /* last error message, NULL if no error */
  288     struct internal_state FAR *state; /* not visible by applications */
  289 
  290     alloc_func zalloc;  /* used to allocate the internal state */
  291     free_func  zfree;   /* used to free the internal state */
  292     voidpf     opaque;  /* private data object passed to zalloc and zfree */
  293 
  294     int     data_type;  /* best guess about the data type: ascii or binary */
  295     uLong   adler;      /* adler32 value of the uncompressed data */
  296     uLong   reserved;   /* reserved for future use */
  297 } z_stream;
  298 
  299 typedef z_stream FAR *z_streamp;
  300 
  301 /*
  302    The application must update next_in and avail_in when avail_in has
  303    dropped to zero. It must update next_out and avail_out when avail_out
  304    has dropped to zero. The application must initialize zalloc, zfree and
  305    opaque before calling the init function. All other fields are set by the
  306    compression library and must not be updated by the application.
  307 
  308    The opaque value provided by the application will be passed as the first
  309    parameter for calls of zalloc and zfree. This can be useful for custom
  310    memory management. The compression library attaches no meaning to the
  311    opaque value.
  312 
  313    zalloc must return Z_NULL if there is not enough memory for the object.
  314    On 16-bit systems, the functions zalloc and zfree must be able to allocate
  315    exactly 65536 bytes, but will not be required to allocate more than this
  316    if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
  317    pointers returned by zalloc for objects of exactly 65536 bytes *must*
  318    have their offset normalized to zero. The default allocation function
  319    provided by this library ensures this (see zutil.c). To reduce memory
  320    requirements and avoid any allocation of 64K objects, at the expense of
  321    compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
  322 
  323    The fields total_in and total_out can be used for statistics or
  324    progress reports. After compression, total_in holds the total size of
  325    the uncompressed data and may be saved for use in the decompressor
  326    (particularly if the decompressor wants to decompress everything in
  327    a single step).
  328 */
  329 
  330                         /* constants */
  331 
  332 #define Z_NO_FLUSH      0
  333 #define Z_PARTIAL_FLUSH 1
  334 #define Z_PACKET_FLUSH  2
  335 #define Z_SYNC_FLUSH    3
  336 #define Z_FULL_FLUSH    4
  337 #define Z_FINISH        5
  338 /* Allowed flush values; see deflate() below for details */
  339 
  340 #define Z_OK            0
  341 #define Z_STREAM_END    1
  342 #define Z_NEED_DICT     2
  343 #define Z_ERRNO        (-1)
  344 #define Z_STREAM_ERROR (-2)
  345 #define Z_DATA_ERROR   (-3)
  346 #define Z_MEM_ERROR    (-4)
  347 #define Z_BUF_ERROR    (-5)
  348 #define Z_VERSION_ERROR (-6)
  349 /* Return codes for the compression/decompression functions. Negative
  350  * values are errors, positive values are used for special but normal events.
  351  */
  352 
  353 #define Z_NO_COMPRESSION         0
  354 #define Z_BEST_SPEED             1
  355 #define Z_BEST_COMPRESSION       9
  356 #define Z_DEFAULT_COMPRESSION  (-1)
  357 /* compression levels */
  358 
  359 #define Z_FILTERED            1
  360 #define Z_HUFFMAN_ONLY        2
  361 #define Z_DEFAULT_STRATEGY    0
  362 /* compression strategy; see deflateInit2() below for details */
  363 
  364 #define Z_BINARY   0
  365 #define Z_ASCII    1
  366 #define Z_UNKNOWN  2
  367 /* Possible values of the data_type field */
  368 
  369 #define Z_DEFLATED   8
  370 /* The deflate compression method (the only one supported in this version) */
  371 
  372 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
  373 
  374 #define zlib_version zlibVersion()
  375 /* for compatibility with versions < 1.0.2 */
  376 
  377                         /* basic functions */
  378 
  379 extern const char * EXPORT zlibVersion OF((void));
  380 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
  381    If the first character differs, the library code actually used is
  382    not compatible with the zlib.h header file used by the application.
  383    This check is automatically made by deflateInit and inflateInit.
  384  */
  385 
  386 /* 
  387 extern int EXPORT deflateInit OF((z_streamp strm, int level));
  388 
  389      Initializes the internal stream state for compression. The fields
  390    zalloc, zfree and opaque must be initialized before by the caller.
  391    If zalloc and zfree are set to Z_NULL, deflateInit updates them to
  392    use default allocation functions.
  393 
  394      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
  395    1 gives best speed, 9 gives best compression, 0 gives no compression at
  396    all (the input data is simply copied a block at a time).
  397    Z_DEFAULT_COMPRESSION requests a default compromise between speed and
  398    compression (currently equivalent to level 6).
  399 
  400      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
  401    enough memory, Z_STREAM_ERROR if level is not a valid compression level,
  402    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
  403    with the version assumed by the caller (ZLIB_VERSION).
  404    msg is set to null if there is no error message.  deflateInit does not
  405    perform any compression: this will be done by deflate().
  406 */
  407 
  408 
  409 extern int EXPORT deflate OF((z_streamp strm, int flush));
  410 /*
  411   Performs one or both of the following actions:
  412 
  413   - Compress more input starting at next_in and update next_in and avail_in
  414     accordingly. If not all input can be processed (because there is not
  415     enough room in the output buffer), next_in and avail_in are updated and
  416     processing will resume at this point for the next call of deflate().
  417 
  418   - Provide more output starting at next_out and update next_out and avail_out
  419     accordingly. This action is forced if the parameter flush is non zero.
  420     Forcing flush frequently degrades the compression ratio, so this parameter
  421     should be set only when necessary (in interactive applications).
  422     Some output may be provided even if flush is not set.
  423 
  424   Before the call of deflate(), the application should ensure that at least
  425   one of the actions is possible, by providing more input and/or consuming
  426   more output, and updating avail_in or avail_out accordingly; avail_out
  427   should never be zero before the call. The application can consume the
  428   compressed output when it wants, for example when the output buffer is full
  429   (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
  430   and with zero avail_out, it must be called again after making room in the
  431   output buffer because there might be more output pending.
  432 
  433     If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression
  434   block is terminated and flushed to the output buffer so that the
  435   decompressor can get all input data available so far. For method 9, a future
  436   variant on method 8, the current block will be flushed but not terminated.
  437   Z_SYNC_FLUSH has the same effect as partial flush except that the compressed
  438   output is byte aligned (the compressor can clear its internal bit buffer)
  439   and the current block is always terminated; this can be useful if the
  440   compressor has to be restarted from scratch after an interruption (in which
  441   case the internal state of the compressor may be lost).
  442     If flush is set to Z_FULL_FLUSH, the compression block is terminated, a
  443   special marker is output and the compression dictionary is discarded; this
  444   is useful to allow the decompressor to synchronize if one compressed block
  445   has been damaged (see inflateSync below).  Flushing degrades compression and
  446   so should be used only when necessary.  Using Z_FULL_FLUSH too often can
  447   seriously degrade the compression. If deflate returns with avail_out == 0,
  448   this function must be called again with the same value of the flush
  449   parameter and more output space (updated avail_out), until the flush is
  450   complete (deflate returns with non-zero avail_out).
  451 
  452     If the parameter flush is set to Z_PACKET_FLUSH, the compression
  453   block is terminated, and a zero-length stored block is output,
  454   omitting the length bytes (the effect of this is that the 3-bit type
  455   code 000 for a stored block is output, and the output is then
  456   byte-aligned).  This is designed for use at the end of a PPP packet.
  457 
  458     If the parameter flush is set to Z_FINISH, pending input is processed,
  459   pending output is flushed and deflate returns with Z_STREAM_END if there
  460   was enough output space; if deflate returns with Z_OK, this function must be
  461   called again with Z_FINISH and more output space (updated avail_out) but no
  462   more input data, until it returns with Z_STREAM_END or an error. After
  463   deflate has returned Z_STREAM_END, the only possible operations on the
  464   stream are deflateReset or deflateEnd.
  465   
  466     Z_FINISH can be used immediately after deflateInit if all the compression
  467   is to be done in a single step. In this case, avail_out must be at least
  468   0.1% larger than avail_in plus 12 bytes.  If deflate does not return
  469   Z_STREAM_END, then it must be called again as described above.
  470 
  471     deflate() may update data_type if it can make a good guess about
  472   the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
  473   binary. This field is only for information purposes and does not affect
  474   the compression algorithm in any manner.
  475 
  476     deflate() returns Z_OK if some progress has been made (more input
  477   processed or more output produced), Z_STREAM_END if all input has been
  478   consumed and all output has been produced (only when flush is set to
  479   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
  480   if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible.
  481 */
  482 
  483 
  484 extern int EXPORT deflateEnd OF((z_streamp strm));
  485 /*
  486      All dynamically allocated data structures for this stream are freed.
  487    This function discards any unprocessed input and does not flush any
  488    pending output.
  489 
  490      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
  491    stream state was inconsistent, Z_DATA_ERROR if the stream was freed
  492    prematurely (some input or output was discarded). In the error case,
  493    msg may be set but then points to a static string (which must not be
  494    deallocated).
  495 */
  496 
  497 
  498 /* 
  499 extern int EXPORT inflateInit OF((z_streamp strm));
  500 
  501      Initializes the internal stream state for decompression. The fields
  502    zalloc, zfree and opaque must be initialized before by the caller.  If
  503    zalloc and zfree are set to Z_NULL, inflateInit updates them to use default
  504    allocation functions.
  505 
  506      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
  507    enough memory, Z_VERSION_ERROR if the zlib library version is incompatible
  508    with the version assumed by the caller.  msg is set to null if there is no
  509    error message. inflateInit does not perform any decompression: this will be
  510    done by inflate().
  511 */
  512 
  513 #if defined(__FreeBSD__) && defined(_KERNEL)
  514 #define inflate       inflate_ppp     /* FreeBSD already has an inflate :-( */
  515 #endif
  516 
  517 extern int EXPORT inflate OF((z_streamp strm, int flush));
  518 /*
  519   Performs one or both of the following actions:
  520 
  521   - Decompress more input starting at next_in and update next_in and avail_in
  522     accordingly. If not all input can be processed (because there is not
  523     enough room in the output buffer), next_in is updated and processing
  524     will resume at this point for the next call of inflate().
  525 
  526   - Provide more output starting at next_out and update next_out and avail_out
  527     accordingly.  inflate() provides as much output as possible, until there
  528     is no more input data or no more space in the output buffer (see below
  529     about the flush parameter).
  530 
  531   Before the call of inflate(), the application should ensure that at least
  532   one of the actions is possible, by providing more input and/or consuming
  533   more output, and updating the next_* and avail_* values accordingly.
  534   The application can consume the uncompressed output when it wants, for
  535   example when the output buffer is full (avail_out == 0), or after each
  536   call of inflate(). If inflate returns Z_OK and with zero avail_out, it
  537   must be called again after making room in the output buffer because there
  538   might be more output pending.
  539 
  540     If the parameter flush is set to Z_PARTIAL_FLUSH or Z_PACKET_FLUSH,
  541   inflate flushes as much output as possible to the output buffer. The
  542   flushing behavior of inflate is not specified for values of the flush
  543   parameter other than Z_PARTIAL_FLUSH, Z_PACKET_FLUSH or Z_FINISH, but the
  544   current implementation actually flushes as much output as possible
  545   anyway.  For Z_PACKET_FLUSH, inflate checks that once all the input data
  546   has been consumed, it is expecting to see the length field of a stored
  547   block; if not, it returns Z_DATA_ERROR.
  548 
  549     inflate() should normally be called until it returns Z_STREAM_END or an
  550   error. However if all decompression is to be performed in a single step
  551   (a single call of inflate), the parameter flush should be set to
  552   Z_FINISH. In this case all pending input is processed and all pending
  553   output is flushed; avail_out must be large enough to hold all the
  554   uncompressed data. (The size of the uncompressed data may have been saved
  555   by the compressor for this purpose.) The next operation on this stream must
  556   be inflateEnd to deallocate the decompression state. The use of Z_FINISH
  557   is never required, but can be used to inform inflate that a faster routine
  558   may be used for the single inflate() call.
  559 
  560     inflate() returns Z_OK if some progress has been made (more input
  561   processed or more output produced), Z_STREAM_END if the end of the
  562   compressed data has been reached and all uncompressed output has been
  563   produced, Z_NEED_DICT if a preset dictionary is needed at this point (see
  564   inflateSetDictionary below), Z_DATA_ERROR if the input data was corrupted,
  565   Z_STREAM_ERROR if the stream structure was inconsistent (for example if
  566   next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
  567   Z_BUF_ERROR if no progress is possible or if there was not enough room in
  568   the output buffer when Z_FINISH is used. In the Z_DATA_ERROR case, the
  569   application may then call inflateSync to look for a good compression block.
  570   In the Z_NEED_DICT case, strm->adler is set to the Adler32 value of the
  571   dictionary chosen by the compressor.
  572 */
  573 
  574 
  575 extern int EXPORT inflateEnd OF((z_streamp strm));
  576 /*
  577      All dynamically allocated data structures for this stream are freed.
  578    This function discards any unprocessed input and does not flush any
  579    pending output.
  580 
  581      inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
  582    was inconsistent. In the error case, msg may be set but then points to a
  583    static string (which must not be deallocated).
  584 */
  585 
  586                         /* Advanced functions */
  587 
  588 /*
  589     The following functions are needed only in some special applications.
  590 */
  591 
  592 /*   
  593 extern int EXPORT deflateInit2 OF((z_streamp strm,
  594                                    int  level,
  595                                    int  method,
  596                                    int  windowBits,
  597                                    int  memLevel,
  598                                    int  strategy));
  599 
  600      This is another version of deflateInit with more compression options. The
  601    fields next_in, zalloc, zfree and opaque must be initialized before by
  602    the caller.
  603 
  604      The method parameter is the compression method. It must be Z_DEFLATED in
  605    this version of the library. (Method 9 will allow a 64K history buffer and
  606    partial block flushes.)
  607 
  608      The windowBits parameter is the base two logarithm of the window size
  609    (the size of the history buffer).  It should be in the range 8..15 for this
  610    version of the library (the value 16 will be allowed for method 9). Larger
  611    values of this parameter result in better compression at the expense of
  612    memory usage. The default value is 15 if deflateInit is used instead.
  613 
  614      The memLevel parameter specifies how much memory should be allocated
  615    for the internal compression state. memLevel=1 uses minimum memory but
  616    is slow and reduces compression ratio; memLevel=9 uses maximum memory
  617    for optimal speed. The default value is 8. See zconf.h for total memory
  618    usage as a function of windowBits and memLevel.
  619 
  620      The strategy parameter is used to tune the compression algorithm. Use the
  621    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
  622    filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
  623    string match).  Filtered data consists mostly of small values with a
  624    somewhat random distribution. In this case, the compression algorithm is
  625    tuned to compress them better. The effect of Z_FILTERED is to force more
  626    Huffman coding and less string matching; it is somewhat intermediate
  627    between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
  628    the compression ratio but not the correctness of the compressed output even
  629    if it is not set appropriately.
  630 
  631      If next_in is not null, the library will use this buffer to hold also
  632    some history information; the buffer must either hold the entire input
  633    data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in
  634    is null, the library will allocate its own history buffer (and leave next_in
  635    null). next_out need not be provided here but must be provided by the
  636    application for the next call of deflate().
  637 
  638      If the history buffer is provided by the application, next_in must
  639    must never be changed by the application since the compressor maintains
  640    information inside this buffer from call to call; the application
  641    must provide more input only by increasing avail_in. next_in is always
  642    reset by the library in this case.
  643 
  644       deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
  645    not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
  646    an invalid method). msg is set to null if there is no error message.
  647    deflateInit2 does not perform any compression: this will be done by
  648    deflate(). 
  649 */
  650                             
  651 extern int EXPORT deflateSetDictionary OF((z_streamp strm,
  652                                            const Bytef *dictionary,
  653                                            uInt  dictLength));
  654 /*
  655      Initializes the compression dictionary (history buffer) from the given
  656    byte sequence without producing any compressed output. This function must
  657    be called immediately after deflateInit or deflateInit2, before any call
  658    of deflate. The compressor and decompressor must use exactly the same
  659    dictionary (see inflateSetDictionary).
  660      The dictionary should consist of strings (byte sequences) that are likely
  661    to be encountered later in the data to be compressed, with the most commonly
  662    used strings preferably put towards the end of the dictionary. Using a
  663    dictionary is most useful when the data to be compressed is short and
  664    can be predicted with good accuracy; the data can then be compressed better
  665    than with the default empty dictionary. In this version of the library,
  666    only the last 32K bytes of the dictionary are used.
  667      Upon return of this function, strm->adler is set to the Adler32 value
  668    of the dictionary; the decompressor may later use this value to determine
  669    which dictionary has been used by the compressor. (The Adler32 value
  670    applies to the whole dictionary even if only a subset of the dictionary is
  671    actually used by the compressor.)
  672 
  673      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
  674    parameter is invalid (such as NULL dictionary) or the stream state
  675    is inconsistent (for example if deflate has already been called for this
  676    stream). deflateSetDictionary does not perform any compression: this will
  677    be done by deflate(). 
  678 */
  679 
  680 extern int EXPORT deflateCopy OF((z_streamp dest,
  681                                   z_streamp source));
  682 /*
  683      Sets the destination stream as a complete copy of the source stream.  If
  684    the source stream is using an application-supplied history buffer, a new
  685    buffer is allocated for the destination stream.  The compressed output
  686    buffer is always application-supplied. It's the responsibility of the
  687    application to provide the correct values of next_out and avail_out for the
  688    next call of deflate.
  689 
  690      This function can be useful when several compression strategies will be
  691    tried, for example when there are several ways of pre-processing the input
  692    data with a filter. The streams that will be discarded should then be freed
  693    by calling deflateEnd.  Note that deflateCopy duplicates the internal
  694    compression state which can be quite large, so this strategy is slow and
  695    can consume lots of memory.
  696 
  697      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
  698    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
  699    (such as zalloc being NULL). msg is left unchanged in both source and
  700    destination.
  701 */
  702 
  703 extern int EXPORT deflateReset OF((z_streamp strm));
  704 /*
  705      This function is equivalent to deflateEnd followed by deflateInit,
  706    but does not free and reallocate all the internal compression state.
  707    The stream will keep the same compression level and any other attributes
  708    that may have been set by deflateInit2.
  709 
  710       deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  711    stream state was inconsistent (such as zalloc or state being NULL).
  712 */
  713 
  714 extern int EXPORT deflateParams OF((z_streamp strm, int level, int strategy));
  715 /*
  716      Dynamically update the compression level and compression strategy.
  717    This can be used to switch between compression and straight copy of
  718    the input data, or to switch to a different kind of input data requiring
  719    a different strategy. If the compression level is changed, the input
  720    available so far is compressed with the old level (and may be flushed);
  721    the new level will take effect only at the next call of deflate().
  722 
  723      Before the call of deflateParams, the stream state must be set as for
  724    a call of deflate(), since the currently available input may have to
  725    be compressed and flushed. In particular, strm->avail_out must be non-zero.
  726 
  727      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
  728    stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
  729    if strm->avail_out was zero.
  730 */
  731 
  732 extern int EXPORT deflateOutputPending OF((z_streamp strm));
  733 /*
  734      Returns the number of bytes of output which are immediately
  735    available from the compressor (i.e. without any further input
  736    or flush).
  737 */
  738 
  739 /*   
  740 extern int EXPORT inflateInit2 OF((z_streamp strm,
  741                                    int  windowBits));
  742 
  743      This is another version of inflateInit with more compression options. The
  744    fields next_out, zalloc, zfree and opaque must be initialized before by
  745    the caller.
  746 
  747      The windowBits parameter is the base two logarithm of the maximum window
  748    size (the size of the history buffer).  It should be in the range 8..15 for
  749    this version of the library (the value 16 will be allowed soon). The
  750    default value is 15 if inflateInit is used instead. If a compressed stream
  751    with a larger window size is given as input, inflate() will return with
  752    the error code Z_DATA_ERROR instead of trying to allocate a larger window.
  753 
  754      If next_out is not null, the library will use this buffer for the history
  755    buffer; the buffer must either be large enough to hold the entire output
  756    data, or have at least 1<<windowBits bytes.  If next_out is null, the
  757    library will allocate its own buffer (and leave next_out null). next_in
  758    need not be provided here but must be provided by the application for the
  759    next call of inflate().
  760 
  761      If the history buffer is provided by the application, next_out must
  762    never be changed by the application since the decompressor maintains
  763    history information inside this buffer from call to call; the application
  764    can only reset next_out to the beginning of the history buffer when
  765    avail_out is zero and all output has been consumed.
  766 
  767       inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
  768    not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
  769    windowBits < 8). msg is set to null if there is no error message.
  770    inflateInit2 does not perform any decompression: this will be done by
  771    inflate().
  772 */
  773 
  774 extern int EXPORT inflateSetDictionary OF((z_streamp strm,
  775                                            const Bytef *dictionary,
  776                                            uInt  dictLength));
  777 /*
  778      Initializes the decompression dictionary (history buffer) from the given
  779    uncompressed byte sequence. This function must be called immediately after
  780    a call of inflate if this call returned Z_NEED_DICT. The dictionary chosen
  781    by the compressor can be determined from the Adler32 value returned by this
  782    call of inflate. The compressor and decompressor must use exactly the same
  783    dictionary (see deflateSetDictionary).
  784 
  785      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
  786    parameter is invalid (such as NULL dictionary) or the stream state is
  787    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
  788    expected one (incorrect Adler32 value). inflateSetDictionary does not
  789    perform any decompression: this will be done by subsequent calls of
  790    inflate().
  791 */
  792 
  793 extern int EXPORT inflateSync OF((z_streamp strm));
  794 /* 
  795     Skips invalid compressed data until the special marker (see deflate()
  796   above) can be found, or until all available input is skipped. No output
  797   is provided.
  798 
  799     inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR
  800   if no more input was provided, Z_DATA_ERROR if no marker has been found,
  801   or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
  802   case, the application may save the current current value of total_in which
  803   indicates where valid compressed data was found. In the error case, the
  804   application may repeatedly call inflateSync, providing more input each time,
  805   until success or end of the input data.
  806 */
  807 
  808 extern int EXPORT inflateReset OF((z_streamp strm));
  809 /*
  810      This function is equivalent to inflateEnd followed by inflateInit,
  811    but does not free and reallocate all the internal decompression state.
  812    The stream will keep attributes that may have been set by inflateInit2.
  813 
  814       inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  815    stream state was inconsistent (such as zalloc or state being NULL).
  816 */
  817 
  818 extern int inflateIncomp OF((z_stream *strm));
  819 /*
  820      This function adds the data at next_in (avail_in bytes) to the output
  821    history without performing any output.  There must be no pending output,
  822    and the decompressor must be expecting to see the start of a block.
  823    Calling this function is equivalent to decompressing a stored block
  824    containing the data at next_in (except that the data is not output).
  825 */
  826 
  827                         /* utility functions */
  828 
  829 /*
  830      The following utility functions are implemented on top of the
  831    basic stream-oriented functions. To simplify the interface, some
  832    default options are assumed (compression level, window size,
  833    standard memory allocation functions). The source code of these
  834    utility functions can easily be modified if you need special options.
  835 */
  836 
  837 extern int EXPORT compress OF((Bytef *dest,   uLongf *destLen,
  838                                const Bytef *source, uLong sourceLen));
  839 /*
  840      Compresses the source buffer into the destination buffer.  sourceLen is
  841    the byte length of the source buffer. Upon entry, destLen is the total
  842    size of the destination buffer, which must be at least 0.1% larger than
  843    sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
  844    compressed buffer.
  845      This function can be used to compress a whole file at once if the
  846    input file is mmap'ed.
  847      compress returns Z_OK if success, Z_MEM_ERROR if there was not
  848    enough memory, Z_BUF_ERROR if there was not enough room in the output
  849    buffer.
  850 */
  851 
  852 extern int EXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
  853                                  const Bytef *source, uLong sourceLen));
  854 /*
  855      Decompresses the source buffer into the destination buffer.  sourceLen is
  856    the byte length of the source buffer. Upon entry, destLen is the total
  857    size of the destination buffer, which must be large enough to hold the
  858    entire uncompressed data. (The size of the uncompressed data must have
  859    been saved previously by the compressor and transmitted to the decompressor
  860    by some mechanism outside the scope of this compression library.)
  861    Upon exit, destLen is the actual size of the compressed buffer.
  862      This function can be used to decompress a whole file at once if the
  863    input file is mmap'ed.
  864 
  865      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
  866    enough memory, Z_BUF_ERROR if there was not enough room in the output
  867    buffer, or Z_DATA_ERROR if the input data was corrupted.
  868 */
  869 
  870 
  871 typedef voidp gzFile;
  872 
  873 extern gzFile EXPORT gzopen  OF((const char *path, const char *mode));
  874 /*
  875      Opens a gzip (.gz) file for reading or writing. The mode parameter
  876    is as in fopen ("rb" or "wb") but can also include a compression level
  877    ("wb9").  gzopen can be used to read a file which is not in gzip format;
  878    in this case gzread will directly read from the file without decompression.
  879      gzopen returns NULL if the file could not be opened or if there was
  880    insufficient memory to allocate the (de)compression state; errno
  881    can be checked to distinguish the two cases (if errno is zero, the
  882    zlib error is Z_MEM_ERROR).
  883 */
  884 
  885 extern gzFile EXPORT gzdopen  OF((int fd, const char *mode));
  886 /*
  887      gzdopen() associates a gzFile with the file descriptor fd.  File
  888    descriptors are obtained from calls like open, dup, creat, pipe or
  889    fileno (in the file has been previously opened with fopen).
  890    The mode parameter is as in gzopen.
  891      The next call of gzclose on the returned gzFile will also close the
  892    file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
  893    descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
  894      gzdopen returns NULL if there was insufficient memory to allocate
  895    the (de)compression state.
  896 */
  897 
  898 extern int EXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));
  899 /*
  900      Reads the given number of uncompressed bytes from the compressed file.
  901    If the input file was not in gzip format, gzread copies the given number
  902    of bytes into the buffer.
  903      gzread returns the number of uncompressed bytes actually read (0 for
  904    end of file, -1 for error). */
  905 
  906 extern int EXPORT    gzwrite OF((gzFile file, const voidp buf, unsigned len));
  907 /*
  908      Writes the given number of uncompressed bytes into the compressed file.
  909    gzwrite returns the number of uncompressed bytes actually written
  910    (0 in case of error).
  911 */
  912 
  913 extern int EXPORT    gzflush OF((gzFile file, int flush));
  914 /*
  915      Flushes all pending output into the compressed file. The parameter
  916    flush is as in the deflate() function. The return value is the zlib
  917    error number (see function gzerror below). gzflush returns Z_OK if
  918    the flush parameter is Z_FINISH and all output could be flushed.
  919      gzflush should be called only when strictly necessary because it can
  920    degrade compression.
  921 */
  922 
  923 extern int EXPORT    gzclose OF((gzFile file));
  924 /*
  925      Flushes all pending output if necessary, closes the compressed file
  926    and deallocates all the (de)compression state. The return value is the zlib
  927    error number (see function gzerror below).
  928 */
  929 
  930 extern const char * EXPORT gzerror OF((gzFile file, int *errnum));
  931 /*
  932      Returns the error message for the last error which occurred on the
  933    given compressed file. errnum is set to zlib error number. If an
  934    error occurred in the filesystem and not in the compression library,
  935    errnum is set to Z_ERRNO and the application may consult errno
  936    to get the exact error code.
  937 */
  938 
  939                         /* checksum functions */
  940 
  941 /*
  942      These functions are not related to compression but are exported
  943    anyway because they might be useful in applications using the
  944    compression library.
  945 */
  946 
  947 extern uLong EXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
  948 
  949 /*
  950      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
  951    return the updated checksum. If buf is NULL, this function returns
  952    the required initial value for the checksum.
  953    An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
  954    much faster. Usage example:
  955 
  956      uLong adler = adler32(0L, Z_NULL, 0);
  957 
  958      while (read_buffer(buffer, length) != EOF) {
  959        adler = adler32(adler, buffer, length);
  960      }
  961      if (adler != original_adler) error();
  962 */
  963 
  964 #if 0
  965 extern uLong EXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
  966 /*
  967      Update a running crc with the bytes buf[0..len-1] and return the updated
  968    crc. If buf is NULL, this function returns the required initial value
  969    for the crc. Pre- and post-conditioning (one's complement) is performed
  970    within this function so it shouldn't be done by the application.
  971    Usage example:
  972 
  973      uLong crc = crc32(0L, Z_NULL, 0);
  974 
  975      while (read_buffer(buffer, length) != EOF) {
  976        crc = crc32(crc, buffer, length);
  977      }
  978      if (crc != original_crc) error();
  979 */
  980 #endif
  981 
  982 
  983                         /* various hacks, don't look :) */
  984 
  985 /* deflateInit and inflateInit are macros to allow checking the zlib version
  986  * and the compiler's view of z_stream:
  987  */
  988 extern int EXPORT deflateInit_ OF((z_streamp strm, int level,
  989                                    const char *version, int stream_size));
  990 extern int EXPORT inflateInit_ OF((z_streamp strm,
  991                                    const char *version, int stream_size));
  992 extern int EXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
  993                                     int windowBits, int memLevel, int strategy,
  994                                     const char *version, int stream_size));
  995 extern int EXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
  996                                     const char *version, int stream_size));
  997 #define deflateInit(strm, level) \
  998         deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
  999 #define inflateInit(strm) \
 1000         inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
 1001 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
 1002         deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
 1003                       (strategy),           ZLIB_VERSION, sizeof(z_stream))
 1004 #define inflateInit2(strm, windowBits) \
 1005         inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
 1006 
 1007 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
 1008     struct internal_state {int dummy;}; /* hack for buggy compilers */
 1009 #endif
 1010 
 1011 uLongf *get_crc_table OF((void)); /* can be used by asm versions of crc32() */
 1012 
 1013 #ifdef __cplusplus
 1014 }
 1015 #endif
 1016 
 1017 #endif /* _ZLIB_H */
 1018 /* --- zlib.h */

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