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

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    1 /* $FreeBSD: src/sys/net/zlib.h,v 1.7 1999/12/29 04:38:38 peter Exp $   */
    2 
    3 /*
    4  * This file is derived from zlib.h and zconf.h from the zlib-1.1.4
    5  * distribution by Jean-loup Gailly and Mark Adler.
    6  */
    7 
    8 /* +++ zlib.h */
    9 /* zlib.h -- interface of the 'zlib' general purpose compression library
   10   version 1.1.4, March 11th, 2002
   11 
   12   Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler
   13 
   14   This software is provided 'as-is', without any express or implied
   15   warranty.  In no event will the authors be held liable for any damages
   16   arising from the use of this software.
   17 
   18   Permission is granted to anyone to use this software for any purpose,
   19   including commercial applications, and to alter it and redistribute it
   20   freely, subject to the following restrictions:
   21 
   22   1. The origin of this software must not be misrepresented; you must not
   23      claim that you wrote the original software. If you use this software
   24      in a product, an acknowledgment in the product documentation would be
   25      appreciated but is not required.
   26   2. Altered source versions must be plainly marked as such, and must not be
   27      misrepresented as being the original software.
   28   3. This notice may not be removed or altered from any source distribution.
   29 
   30   Jean-loup Gailly        Mark Adler
   31   jloup@gzip.org          madler@alumni.caltech.edu
   32 
   33 
   34   The data format used by the zlib library is described by RFCs (Request for
   35   Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
   36   (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
   37 */
   38 
   39 #ifndef _ZLIB_H
   40 #define _ZLIB_H
   41 #include <sys/appleapiopts.h>
   42 
   43 #if !defined(KERNEL) || defined(__APPLE_API_PRIVATE)
   44 
   45 #if __cplusplus
   46 extern "C" {
   47 #endif
   48 
   49 
   50 /* +++ zconf.h */
   51 /* zconf.h -- configuration of the zlib compression library
   52  * Copyright (C) 1995-2002 Jean-loup Gailly.
   53  * For conditions of distribution and use, see copyright notice in zlib.h 
   54  */
   55 
   56 #ifndef _ZCONF_H
   57 #define _ZCONF_H
   58 
   59 /*
   60  * If you *really* need a unique prefix for all types and library functions,
   61  * compile with -DZ_PREFIX. The "standard" zlib should be compiled without it.
   62  */
   63 #ifdef Z_PREFIX
   64 #  define deflateInit_  z_deflateInit_
   65 #  define deflate       z_deflate
   66 #  define deflateEnd    z_deflateEnd
   67 #  define inflateInit_  z_inflateInit_
   68 #  define inflate       z_inflate
   69 #  define inflateEnd    z_inflateEnd
   70 #  define deflateInit2_ z_deflateInit2_
   71 #  define deflateSetDictionary z_deflateSetDictionary
   72 #  define deflateCopy   z_deflateCopy
   73 #  define deflateReset  z_deflateReset
   74 #  define deflateParams z_deflateParams
   75 #  define inflateInit2_ z_inflateInit2_
   76 #  define inflateSetDictionary z_inflateSetDictionary
   77 #  define inflateSync   z_inflateSync
   78 #  define inflateSyncPoint z_inflateSyncPoint
   79 #  define inflateReset  z_inflateReset
   80 #  define compress      z_compress
   81 #  define compress2     z_compress2
   82 #  define uncompress    z_uncompress
   83 #  define adler32       z_adler32
   84 #  define crc32         z_crc32
   85 #  define get_crc_table z_get_crc_table
   86 
   87 #  define Byte          z_Byte
   88 #  define uInt          z_uInt
   89 #  define uLong         z_uLong
   90 #  define Bytef         z_Bytef
   91 #  define charf         z_charf
   92 #  define intf          z_intf
   93 #  define uIntf         z_uIntf
   94 #  define uLongf        z_uLongf
   95 #  define voidpf        z_voidpf
   96 #  define voidp         z_voidp
   97 #endif
   98 
   99 #if (defined(_WIN32) || defined(__WIN32__)) && !defined(WIN32)
  100 #  define WIN32
  101 #endif
  102 #if defined(__GNUC__) || defined(WIN32) || defined(__386__) || defined(i386)
  103 #  ifndef __32BIT__
  104 #    define __32BIT__
  105 #  endif
  106 #endif
  107 #if defined(__MSDOS__) && !defined(MSDOS)
  108 #  define MSDOS
  109 #endif
  110 
  111 /*
  112  * Compile with -DMAXSEG_64K if the alloc function cannot allocate more
  113  * than 64k bytes at a time (needed on systems with 16-bit int).
  114  */
  115 #if defined(MSDOS) && !defined(__32BIT__)
  116 #  define MAXSEG_64K
  117 #endif
  118 #ifdef MSDOS
  119 #  define UNALIGNED_OK
  120 #endif
  121 
  122 #if (defined(MSDOS) || defined(_WINDOWS) || defined(WIN32))  && !defined(STDC)
  123 #  define STDC
  124 #endif
  125 #if defined(__STDC__) || defined(__cplusplus) || defined(__OS2__)
  126 #  ifndef STDC
  127 #    define STDC
  128 #  endif
  129 #endif
  130 
  131 #ifndef STDC
  132 #  ifndef const /* cannot use !defined(STDC) && !defined(const) on Mac */
  133 #    define const
  134 #  endif
  135 #endif
  136 
  137 /* Some Mac compilers merge all .h files incorrectly: */
  138 #if defined(__MWERKS__) || defined(applec) ||defined(THINK_C) ||defined(__SC__)
  139 #  define NO_DUMMY_DECL
  140 #endif
  141 
  142 /* Old Borland C incorrectly complains about missing returns: */
  143 #if defined(__BORLANDC__) && (__BORLANDC__ < 0x500)
  144 #  define NEED_DUMMY_RETURN
  145 #endif
  146 
  147 
  148 /* Maximum value for memLevel in deflateInit2 */
  149 #ifndef MAX_MEM_LEVEL
  150 #  ifdef MAXSEG_64K
  151 #    define MAX_MEM_LEVEL 8
  152 #  else
  153 #    define MAX_MEM_LEVEL 9
  154 #  endif
  155 #endif
  156 
  157 /* Maximum value for windowBits in deflateInit2 and inflateInit2.
  158  * WARNING: reducing MAX_WBITS makes minigzip unable to extract .gz files
  159  * created by gzip. (Files created by minigzip can still be extracted by
  160  * gzip.)
  161  */
  162 #ifndef MAX_WBITS
  163 #  define MAX_WBITS   15 /* 32K LZ77 window */
  164 #endif
  165 
  166 /* The memory requirements for deflate are (in bytes):
  167             (1 << (windowBits+2)) +  (1 << (memLevel+9))
  168  that is: 128K for windowBits=15  +  128K for memLevel = 8  (default values)
  169  plus a few kilobytes for small objects. For example, if you want to reduce
  170  the default memory requirements from 256K to 128K, compile with
  171      make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
  172  Of course this will generally degrade compression (there's no free lunch).
  173 
  174    The memory requirements for inflate are (in bytes) 1 << windowBits
  175  that is, 32K for windowBits=15 (default value) plus a few kilobytes
  176  for small objects.
  177 */
  178 
  179                         /* Type declarations */
  180 
  181 #ifndef OF /* function prototypes */
  182 #  ifdef STDC
  183 #    define OF(args)  args
  184 #  else
  185 #    define OF(args)  ()
  186 #  endif
  187 #endif
  188 
  189 /* The following definitions for FAR are needed only for MSDOS mixed
  190  * model programming (small or medium model with some far allocations).
  191  * This was tested only with MSC; for other MSDOS compilers you may have
  192  * to define NO_MEMCPY in zutil.h.  If you don't need the mixed model,
  193  * just define FAR to be empty.
  194  */
  195 #if (defined(M_I86SM) || defined(M_I86MM)) && !defined(__32BIT__)
  196    /* MSC small or medium model */
  197 #  define SMALL_MEDIUM
  198 #  ifdef _MSC_VER
  199 #    define FAR _far
  200 #  else
  201 #    define FAR far
  202 #  endif
  203 #endif
  204 #if defined(__BORLANDC__) && (defined(__SMALL__) || defined(__MEDIUM__))
  205 #  ifndef __32BIT__
  206 #    define SMALL_MEDIUM
  207 #    define FAR _far
  208 #  endif
  209 #endif
  210 
  211 /* Compile with -DZLIB_DLL for Windows DLL support */
  212 #if defined(ZLIB_DLL)
  213 #  if defined(_WINDOWS) || defined(WINDOWS)
  214 #    ifdef FAR
  215 #      undef FAR
  216 #    endif
  217 #    include <windows.h>
  218 #    define ZEXPORT  WINAPI
  219 #    ifdef WIN32
  220 #      define ZEXPORTVA  WINAPIV
  221 #    else
  222 #      define ZEXPORTVA  FAR _cdecl _export
  223 #    endif
  224 #  endif
  225 #  if defined (__BORLANDC__)
  226 #    if (__BORLANDC__ >= 0x0500) && defined (WIN32)
  227 #      include <windows.h>
  228 #      define ZEXPORT __declspec(dllexport) WINAPI
  229 #      define ZEXPORTRVA __declspec(dllexport) WINAPIV
  230 #    else
  231 #      if defined (_Windows) && defined (__DLL__)
  232 #        define ZEXPORT _export
  233 #        define ZEXPORTVA _export
  234 #      endif
  235 #    endif
  236 #  endif
  237 #endif
  238 
  239 #if defined (__BEOS__)
  240 #  if defined (ZLIB_DLL)
  241 #    define ZEXTERN extern __declspec(dllexport)
  242 #  else
  243 #    define ZEXTERN extern __declspec(dllimport)
  244 #  endif
  245 #endif
  246 
  247 #ifndef ZEXPORT
  248 #  define ZEXPORT
  249 #endif
  250 #ifndef ZEXPORTVA
  251 #  define ZEXPORTVA
  252 #endif
  253 #ifndef ZEXTERN
  254 #  define ZEXTERN extern
  255 #endif
  256 
  257 #ifndef FAR
  258 #   define FAR
  259 #endif
  260 
  261 #if !defined(MACOS) && !defined(TARGET_OS_MAC)
  262 typedef unsigned char  Byte;  /* 8 bits */
  263 #endif
  264 typedef unsigned int   uInt;  /* 16 bits or more */
  265 typedef unsigned long  uLong; /* 32 bits or more */
  266 
  267 #ifdef SMALL_MEDIUM
  268    /* Borland C/C++ and some old MSC versions ignore FAR inside typedef */
  269 #  define Bytef Byte FAR
  270 #else
  271    typedef Byte  FAR Bytef;
  272 #endif
  273 typedef char  FAR charf;
  274 typedef int   FAR intf;
  275 typedef uInt  FAR uIntf;
  276 typedef uLong FAR uLongf;
  277 
  278 #ifdef STDC
  279    typedef void FAR *voidpf;
  280    typedef void     *voidp;
  281 #else
  282    typedef Byte FAR *voidpf;
  283    typedef Byte     *voidp;
  284 #endif
  285 
  286 #ifdef HAVE_UNISTD_H
  287 #  include <sys/types.h> /* for off_t */
  288 #  include <unistd.h>    /* for SEEK_* and off_t */
  289 #  define z_off_t  off_t
  290 #endif
  291 #ifndef SEEK_SET
  292 #  define SEEK_SET        0       /* Seek from beginning of file.  */
  293 #  define SEEK_CUR        1       /* Seek from current position.  */
  294 #  define SEEK_END        2       /* Set file pointer to EOF plus "offset" */
  295 #endif
  296 #ifndef z_off_t
  297 #  define  z_off_t long
  298 #endif
  299 
  300 /* MVS linker does not support external names larger than 8 bytes */
  301 #if defined(__MVS__)
  302 #   pragma map(deflateInit_,"DEIN")
  303 #   pragma map(deflateInit2_,"DEIN2")
  304 #   pragma map(deflateEnd,"DEEND")
  305 #   pragma map(inflateInit_,"ININ")
  306 #   pragma map(inflateInit2_,"ININ2")
  307 #   pragma map(inflateEnd,"INEND")
  308 #   pragma map(inflateSync,"INSY")
  309 #   pragma map(inflateSetDictionary,"INSEDI")
  310 #   pragma map(inflate_blocks,"INBL")
  311 #   pragma map(inflate_blocks_new,"INBLNE")
  312 #   pragma map(inflate_blocks_free,"INBLFR")
  313 #   pragma map(inflate_blocks_reset,"INBLRE")
  314 #   pragma map(inflate_codes_free,"INCOFR")
  315 #   pragma map(inflate_codes,"INCO")
  316 #   pragma map(inflate_fast,"INFA")
  317 #   pragma map(inflate_flush,"INFLU")
  318 #   pragma map(inflate_mask,"INMA")
  319 #   pragma map(inflate_set_dictionary,"INSEDI2")
  320 #   pragma map(inflate_copyright,"INCOPY")
  321 #   pragma map(inflate_trees_bits,"INTRBI")
  322 #   pragma map(inflate_trees_dynamic,"INTRDY")
  323 #   pragma map(inflate_trees_fixed,"INTRFI")
  324 #   pragma map(inflate_trees_free,"INTRFR")
  325 #endif
  326 
  327 #endif /* _ZCONF_H */
  328 /* --- zconf.h */
  329 
  330 #define ZLIB_VERSION "1.1.4"
  331 
  332 /* 
  333      The 'zlib' compression library provides in-memory compression and
  334   decompression functions, including integrity checks of the uncompressed
  335   data.  This version of the library supports only one compression method
  336   (deflation) but other algorithms will be added later and will have the same
  337   stream interface.
  338 
  339      Compression can be done in a single step if the buffers are large
  340   enough (for example if an input file is mmap'ed), or can be done by
  341   repeated calls of the compression function.  In the latter case, the
  342   application must provide more input and/or consume the output
  343   (providing more output space) before each call.
  344 
  345      The library also supports reading and writing files in gzip (.gz) format
  346   with an interface similar to that of stdio.
  347 
  348      The library does not install any signal handler. The decoder checks
  349   the consistency of the compressed data, so the library should never
  350   crash even in case of corrupted input.
  351 */
  352 
  353 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
  354 typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
  355 
  356 struct internal_state;
  357 
  358 typedef struct z_stream_s {
  359     Bytef    *next_in;  /* next input byte */
  360     uInt     avail_in;  /* number of bytes available at next_in */
  361     uLong    total_in;  /* total nb of input bytes read so far */
  362 
  363     Bytef    *next_out; /* next output byte should be put there */
  364     uInt     avail_out; /* remaining free space at next_out */
  365     uLong    total_out; /* total nb of bytes output so far */
  366 
  367     char     *msg;      /* last error message, NULL if no error */
  368     struct internal_state FAR *state; /* not visible by applications */
  369 
  370     alloc_func zalloc;  /* used to allocate the internal state */
  371     free_func  zfree;   /* used to free the internal state */
  372     voidpf     opaque;  /* private data object passed to zalloc and zfree */
  373 
  374     int     data_type;  /* best guess about the data type: ascii or binary */
  375     uLong   adler;      /* adler32 value of the uncompressed data */
  376     uLong   reserved;   /* reserved for future use */
  377 } z_stream;
  378 
  379 typedef z_stream FAR *z_streamp;
  380 
  381 /*
  382    The application must update next_in and avail_in when avail_in has
  383    dropped to zero. It must update next_out and avail_out when avail_out
  384    has dropped to zero. The application must initialize zalloc, zfree and
  385    opaque before calling the init function. All other fields are set by the
  386    compression library and must not be updated by the application.
  387 
  388    The opaque value provided by the application will be passed as the first
  389    parameter for calls of zalloc and zfree. This can be useful for custom
  390    memory management. The compression library attaches no meaning to the
  391    opaque value.
  392 
  393    zalloc must return Z_NULL if there is not enough memory for the object.
  394    If zlib is used in a multi-threaded application, zalloc and zfree must be
  395    thread safe.
  396 
  397    On 16-bit systems, the functions zalloc and zfree must be able to allocate
  398    exactly 65536 bytes, but will not be required to allocate more than this
  399    if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
  400    pointers returned by zalloc for objects of exactly 65536 bytes *must*
  401    have their offset normalized to zero. The default allocation function
  402    provided by this library ensures this (see zutil.c). To reduce memory
  403    requirements and avoid any allocation of 64K objects, at the expense of
  404    compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
  405 
  406    The fields total_in and total_out can be used for statistics or
  407    progress reports. After compression, total_in holds the total size of
  408    the uncompressed data and may be saved for use in the decompressor
  409    (particularly if the decompressor wants to decompress everything in
  410    a single step).
  411 */
  412 
  413                         /* constants */
  414 
  415 #define Z_NO_FLUSH      0
  416 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
  417 #define Z_PACKET_FLUSH  2
  418 #define Z_SYNC_FLUSH    3
  419 #define Z_FULL_FLUSH    4
  420 #define Z_FINISH        5
  421 /* Allowed flush values; see deflate() below for details */
  422 
  423 #define Z_OK            0
  424 #define Z_STREAM_END    1
  425 #define Z_NEED_DICT     2
  426 #define Z_ERRNO        (-1)
  427 #define Z_STREAM_ERROR (-2)
  428 #define Z_DATA_ERROR   (-3)
  429 #define Z_MEM_ERROR    (-4)
  430 #define Z_BUF_ERROR    (-5)
  431 #define Z_VERSION_ERROR (-6)
  432 /* Return codes for the compression/decompression functions. Negative
  433  * values are errors, positive values are used for special but normal events.
  434  */
  435 
  436 #define Z_NO_COMPRESSION         0
  437 #define Z_BEST_SPEED             1
  438 #define Z_BEST_COMPRESSION       9
  439 #define Z_DEFAULT_COMPRESSION  (-1)
  440 /* compression levels */
  441 
  442 #define Z_FILTERED            1
  443 #define Z_HUFFMAN_ONLY        2
  444 #define Z_DEFAULT_STRATEGY    0
  445 /* compression strategy; see deflateInit2() below for details */
  446 
  447 #define Z_BINARY   0
  448 #define Z_ASCII    1
  449 #define Z_UNKNOWN  2
  450 /* Possible values of the data_type field */
  451 
  452 #define Z_DEFLATED   8
  453 /* The deflate compression method (the only one supported in this version) */
  454 
  455 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
  456 
  457 #define zlib_version zlibVersion()
  458 /* for compatibility with versions < 1.0.2 */
  459 
  460                         /* basic functions */
  461 
  462 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
  463 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
  464    If the first character differs, the library code actually used is
  465    not compatible with the zlib.h header file used by the application.
  466    This check is automatically made by deflateInit and inflateInit.
  467  */
  468 
  469 /* 
  470 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
  471 
  472      Initializes the internal stream state for compression. The fields
  473    zalloc, zfree and opaque must be initialized before by the caller.
  474    If zalloc and zfree are set to Z_NULL, deflateInit updates them to
  475    use default allocation functions.
  476 
  477      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
  478    1 gives best speed, 9 gives best compression, 0 gives no compression at
  479    all (the input data is simply copied a block at a time).
  480    Z_DEFAULT_COMPRESSION requests a default compromise between speed and
  481    compression (currently equivalent to level 6).
  482 
  483      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
  484    enough memory, Z_STREAM_ERROR if level is not a valid compression level,
  485    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
  486    with the version assumed by the caller (ZLIB_VERSION).
  487    msg is set to null if there is no error message.  deflateInit does not
  488    perform any compression: this will be done by deflate().
  489 */
  490 
  491 
  492 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
  493 /*
  494     deflate compresses as much data as possible, and stops when the input
  495   buffer becomes empty or the output buffer becomes full. It may introduce some
  496   output latency (reading input without producing any output) except when
  497   forced to flush.
  498 
  499     The detailed semantics are as follows. deflate performs one or both of the
  500   following actions:
  501 
  502   - Compress more input starting at next_in and update next_in and avail_in
  503     accordingly. If not all input can be processed (because there is not
  504     enough room in the output buffer), next_in and avail_in are updated and
  505     processing will resume at this point for the next call of deflate().
  506 
  507   - Provide more output starting at next_out and update next_out and avail_out
  508     accordingly. This action is forced if the parameter flush is non zero.
  509     Forcing flush frequently degrades the compression ratio, so this parameter
  510     should be set only when necessary (in interactive applications).
  511     Some output may be provided even if flush is not set.
  512 
  513   Before the call of deflate(), the application should ensure that at least
  514   one of the actions is possible, by providing more input and/or consuming
  515   more output, and updating avail_in or avail_out accordingly; avail_out
  516   should never be zero before the call. The application can consume the
  517   compressed output when it wants, for example when the output buffer is full
  518   (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
  519   and with zero avail_out, it must be called again after making room in the
  520   output buffer because there might be more output pending.
  521 
  522     If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
  523   flushed to the output buffer and the output is aligned on a byte boundary, so
  524   that the decompressor can get all input data available so far. (In particular
  525   avail_in is zero after the call if enough output space has been provided
  526   before the call.)  Flushing may degrade compression for some compression
  527   algorithms and so it should be used only when necessary.
  528 
  529     If flush is set to Z_FULL_FLUSH, all output is flushed as with
  530   Z_SYNC_FLUSH, and the compression state is reset so that decompression can
  531   restart from this point if previous compressed data has been damaged or if
  532   random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
  533   the compression.
  534 
  535     If deflate returns with avail_out == 0, this function must be called again
  536   with the same value of the flush parameter and more output space (updated
  537   avail_out), until the flush is complete (deflate returns with non-zero
  538   avail_out).
  539 
  540     If the parameter flush is set to Z_FINISH, pending input is processed,
  541   pending output is flushed and deflate returns with Z_STREAM_END if there
  542   was enough output space; if deflate returns with Z_OK, this function must be
  543   called again with Z_FINISH and more output space (updated avail_out) but no
  544   more input data, until it returns with Z_STREAM_END or an error. After
  545   deflate has returned Z_STREAM_END, the only possible operations on the
  546   stream are deflateReset or deflateEnd.
  547   
  548     Z_FINISH can be used immediately after deflateInit if all the compression
  549   is to be done in a single step. In this case, avail_out must be at least
  550   0.1% larger than avail_in plus 12 bytes.  If deflate does not return
  551   Z_STREAM_END, then it must be called again as described above.
  552 
  553     deflate() sets strm->adler to the adler32 checksum of all input read
  554   so far (that is, total_in bytes).
  555 
  556     deflate() may update data_type if it can make a good guess about
  557   the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
  558   binary. This field is only for information purposes and does not affect
  559   the compression algorithm in any manner.
  560 
  561     deflate() returns Z_OK if some progress has been made (more input
  562   processed or more output produced), Z_STREAM_END if all input has been
  563   consumed and all output has been produced (only when flush is set to
  564   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
  565   if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
  566   (for example avail_in or avail_out was zero).
  567 */
  568 
  569 
  570 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
  571 /*
  572      All dynamically allocated data structures for this stream are freed.
  573    This function discards any unprocessed input and does not flush any
  574    pending output.
  575 
  576      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
  577    stream state was inconsistent, Z_DATA_ERROR if the stream was freed
  578    prematurely (some input or output was discarded). In the error case,
  579    msg may be set but then points to a static string (which must not be
  580    deallocated).
  581 */
  582 
  583 
  584 /* 
  585 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
  586 
  587      Initializes the internal stream state for decompression. The fields
  588    next_in, avail_in, zalloc, zfree and opaque must be initialized before by
  589    the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
  590    value depends on the compression method), inflateInit determines the
  591    compression method from the zlib header and allocates all data structures
  592    accordingly; otherwise the allocation will be deferred to the first call of
  593    inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
  594    use default allocation functions.
  595 
  596      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
  597    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
  598    version assumed by the caller.  msg is set to null if there is no error
  599    message. inflateInit does not perform any decompression apart from reading
  600    the zlib header if present: this will be done by inflate().  (So next_in and
  601    avail_in may be modified, but next_out and avail_out are unchanged.)
  602 */
  603 
  604 
  605 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
  606 /*
  607     inflate decompresses as much data as possible, and stops when the input
  608   buffer becomes empty or the output buffer becomes full. It may some
  609   introduce some output latency (reading input without producing any output)
  610   except when forced to flush.
  611 
  612   The detailed semantics are as follows. inflate performs one or both of the
  613   following actions:
  614 
  615   - Decompress more input starting at next_in and update next_in and avail_in
  616     accordingly. If not all input can be processed (because there is not
  617     enough room in the output buffer), next_in is updated and processing
  618     will resume at this point for the next call of inflate().
  619 
  620   - Provide more output starting at next_out and update next_out and avail_out
  621     accordingly.  inflate() provides as much output as possible, until there
  622     is no more input data or no more space in the output buffer (see below
  623     about the flush parameter).
  624 
  625   Before the call of inflate(), the application should ensure that at least
  626   one of the actions is possible, by providing more input and/or consuming
  627   more output, and updating the next_* and avail_* values accordingly.
  628   The application can consume the uncompressed output when it wants, for
  629   example when the output buffer is full (avail_out == 0), or after each
  630   call of inflate(). If inflate returns Z_OK and with zero avail_out, it
  631   must be called again after making room in the output buffer because there
  632   might be more output pending.
  633 
  634     If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
  635   output as possible to the output buffer. The flushing behavior of inflate is
  636   not specified for values of the flush parameter other than Z_SYNC_FLUSH
  637   and Z_FINISH, but the current implementation actually flushes as much output
  638   as possible anyway.
  639 
  640     inflate() should normally be called until it returns Z_STREAM_END or an
  641   error. However if all decompression is to be performed in a single step
  642   (a single call of inflate), the parameter flush should be set to
  643   Z_FINISH. In this case all pending input is processed and all pending
  644   output is flushed; avail_out must be large enough to hold all the
  645   uncompressed data. (The size of the uncompressed data may have been saved
  646   by the compressor for this purpose.) The next operation on this stream must
  647   be inflateEnd to deallocate the decompression state. The use of Z_FINISH
  648   is never required, but can be used to inform inflate that a faster routine
  649   may be used for the single inflate() call.
  650 
  651      If a preset dictionary is needed at this point (see inflateSetDictionary
  652   below), inflate sets strm-adler to the adler32 checksum of the
  653   dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise 
  654   it sets strm->adler to the adler32 checksum of all output produced
  655   so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
  656   an error code as described below. At the end of the stream, inflate()
  657   checks that its computed adler32 checksum is equal to that saved by the
  658   compressor and returns Z_STREAM_END only if the checksum is correct.
  659 
  660     inflate() returns Z_OK if some progress has been made (more input processed
  661   or more output produced), Z_STREAM_END if the end of the compressed data has
  662   been reached and all uncompressed output has been produced, Z_NEED_DICT if a
  663   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
  664   corrupted (input stream not conforming to the zlib format or incorrect
  665   adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
  666   (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
  667   enough memory, Z_BUF_ERROR if no progress is possible or if there was not
  668   enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
  669   case, the application may then call inflateSync to look for a good
  670   compression block.
  671 */
  672 
  673 
  674 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
  675 /*
  676      All dynamically allocated data structures for this stream are freed.
  677    This function discards any unprocessed input and does not flush any
  678    pending output.
  679 
  680      inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
  681    was inconsistent. In the error case, msg may be set but then points to a
  682    static string (which must not be deallocated).
  683 */
  684 
  685                         /* Advanced functions */
  686 
  687 /*
  688     The following functions are needed only in some special applications.
  689 */
  690 
  691 /*   
  692 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
  693                                      int  level,
  694                                      int  method,
  695                                      int  windowBits,
  696                                      int  memLevel,
  697                                      int  strategy));
  698 
  699      This is another version of deflateInit with more compression options. The
  700    fields next_in, zalloc, zfree and opaque must be initialized before by
  701    the caller.
  702 
  703      The method parameter is the compression method. It must be Z_DEFLATED in
  704    this version of the library.
  705 
  706      The windowBits parameter is the base two logarithm of the window size
  707    (the size of the history buffer).  It should be in the range 8..15 for this
  708    version of the library. Larger values of this parameter result in better
  709    compression at the expense of memory usage. The default value is 15 if
  710    deflateInit is used instead.
  711 
  712      The memLevel parameter specifies how much memory should be allocated
  713    for the internal compression state. memLevel=1 uses minimum memory but
  714    is slow and reduces compression ratio; memLevel=9 uses maximum memory
  715    for optimal speed. The default value is 8. See zconf.h for total memory
  716    usage as a function of windowBits and memLevel.
  717 
  718      The strategy parameter is used to tune the compression algorithm. Use the
  719    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
  720    filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
  721    string match).  Filtered data consists mostly of small values with a
  722    somewhat random distribution. In this case, the compression algorithm is
  723    tuned to compress them better. The effect of Z_FILTERED is to force more
  724    Huffman coding and less string matching; it is somewhat intermediate
  725    between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
  726    the compression ratio but not the correctness of the compressed output even
  727    if it is not set appropriately.
  728 
  729       deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  730    memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
  731    method). msg is set to null if there is no error message.  deflateInit2 does
  732    not perform any compression: this will be done by deflate().
  733 */
  734                             
  735 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
  736                                              const Bytef *dictionary,
  737                                              uInt  dictLength));
  738 /*
  739      Initializes the compression dictionary from the given byte sequence
  740    without producing any compressed output. This function must be called
  741    immediately after deflateInit, deflateInit2 or deflateReset, before any
  742    call of deflate. The compressor and decompressor must use exactly the same
  743    dictionary (see inflateSetDictionary).
  744 
  745      The dictionary should consist of strings (byte sequences) that are likely
  746    to be encountered later in the data to be compressed, with the most commonly
  747    used strings preferably put towards the end of the dictionary. Using a
  748    dictionary is most useful when the data to be compressed is short and can be
  749    predicted with good accuracy; the data can then be compressed better than
  750    with the default empty dictionary.
  751 
  752      Depending on the size of the compression data structures selected by
  753    deflateInit or deflateInit2, a part of the dictionary may in effect be
  754    discarded, for example if the dictionary is larger than the window size in
  755    deflate or deflate2. Thus the strings most likely to be useful should be
  756    put at the end of the dictionary, not at the front.
  757 
  758      Upon return of this function, strm->adler is set to the Adler32 value
  759    of the dictionary; the decompressor may later use this value to determine
  760    which dictionary has been used by the compressor. (The Adler32 value
  761    applies to the whole dictionary even if only a subset of the dictionary is
  762    actually used by the compressor.)
  763 
  764      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
  765    parameter is invalid (such as NULL dictionary) or the stream state is
  766    inconsistent (for example if deflate has already been called for this stream
  767    or if the compression method is bsort). deflateSetDictionary does not
  768    perform any compression: this will be done by deflate().
  769 */
  770 
  771 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
  772                                     z_streamp source));
  773 /*
  774      Sets the destination stream as a complete copy of the source stream.
  775 
  776      This function can be useful when several compression strategies will be
  777    tried, for example when there are several ways of pre-processing the input
  778    data with a filter. The streams that will be discarded should then be freed
  779    by calling deflateEnd.  Note that deflateCopy duplicates the internal
  780    compression state which can be quite large, so this strategy is slow and
  781    can consume lots of memory.
  782 
  783      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
  784    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
  785    (such as zalloc being NULL). msg is left unchanged in both source and
  786    destination.
  787 */
  788 
  789 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
  790 /*
  791      This function is equivalent to deflateEnd followed by deflateInit,
  792    but does not free and reallocate all the internal compression state.
  793    The stream will keep the same compression level and any other attributes
  794    that may have been set by deflateInit2.
  795 
  796       deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  797    stream state was inconsistent (such as zalloc or state being NULL).
  798 */
  799 
  800 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
  801                                       int level,
  802                                       int strategy));
  803 /*
  804      Dynamically update the compression level and compression strategy.  The
  805    interpretation of level and strategy is as in deflateInit2.  This can be
  806    used to switch between compression and straight copy of the input data, or
  807    to switch to a different kind of input data requiring a different
  808    strategy. If the compression level is changed, the input available so far
  809    is compressed with the old level (and may be flushed); the new level will
  810    take effect only at the next call of deflate().
  811 
  812      Before the call of deflateParams, the stream state must be set as for
  813    a call of deflate(), since the currently available input may have to
  814    be compressed and flushed. In particular, strm->avail_out must be non-zero.
  815 
  816      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
  817    stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
  818    if strm->avail_out was zero.
  819 */
  820 
  821 /*   
  822 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
  823                                      int  windowBits));
  824 
  825      This is another version of inflateInit with an extra parameter. The
  826    fields next_in, avail_in, zalloc, zfree and opaque must be initialized
  827    before by the caller.
  828 
  829      The windowBits parameter is the base two logarithm of the maximum window
  830    size (the size of the history buffer).  It should be in the range 8..15 for
  831    this version of the library. The default value is 15 if inflateInit is used
  832    instead. If a compressed stream with a larger window size is given as
  833    input, inflate() will return with the error code Z_DATA_ERROR instead of
  834    trying to allocate a larger window.
  835 
  836       inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  837    memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
  838    memLevel). msg is set to null if there is no error message.  inflateInit2
  839    does not perform any decompression apart from reading the zlib header if
  840    present: this will be done by inflate(). (So next_in and avail_in may be
  841    modified, but next_out and avail_out are unchanged.)
  842 */
  843 
  844 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
  845                                              const Bytef *dictionary,
  846                                              uInt  dictLength));
  847 /*
  848      Initializes the decompression dictionary from the given uncompressed byte
  849    sequence. This function must be called immediately after a call of inflate
  850    if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
  851    can be determined from the Adler32 value returned by this call of
  852    inflate. The compressor and decompressor must use exactly the same
  853    dictionary (see deflateSetDictionary).
  854 
  855      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
  856    parameter is invalid (such as NULL dictionary) or the stream state is
  857    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
  858    expected one (incorrect Adler32 value). inflateSetDictionary does not
  859    perform any decompression: this will be done by subsequent calls of
  860    inflate().
  861 */
  862 
  863 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
  864 /* 
  865     Skips invalid compressed data until a full flush point (see above the
  866   description of deflate with Z_FULL_FLUSH) can be found, or until all
  867   available input is skipped. No output is provided.
  868 
  869     inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
  870   if no more input was provided, Z_DATA_ERROR if no flush point has been found,
  871   or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
  872   case, the application may save the current current value of total_in which
  873   indicates where valid compressed data was found. In the error case, the
  874   application may repeatedly call inflateSync, providing more input each time,
  875   until success or end of the input data.
  876 */
  877 
  878 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
  879 /*
  880      This function is equivalent to inflateEnd followed by inflateInit,
  881    but does not free and reallocate all the internal decompression state.
  882    The stream will keep attributes that may have been set by inflateInit2.
  883 
  884       inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  885    stream state was inconsistent (such as zalloc or state being NULL).
  886 */
  887 
  888 
  889                         /* utility functions */
  890 
  891 /*
  892      The following utility functions are implemented on top of the
  893    basic stream-oriented functions. To simplify the interface, some
  894    default options are assumed (compression level and memory usage,
  895    standard memory allocation functions). The source code of these
  896    utility functions can easily be modified if you need special options.
  897 */
  898 
  899 ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
  900                                  const Bytef *source, uLong sourceLen));
  901 /*
  902      Compresses the source buffer into the destination buffer.  sourceLen is
  903    the byte length of the source buffer. Upon entry, destLen is the total
  904    size of the destination buffer, which must be at least 0.1% larger than
  905    sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
  906    compressed buffer.
  907      This function can be used to compress a whole file at once if the
  908    input file is mmap'ed.
  909      compress returns Z_OK if success, Z_MEM_ERROR if there was not
  910    enough memory, Z_BUF_ERROR if there was not enough room in the output
  911    buffer.
  912 */
  913 
  914 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
  915                                   const Bytef *source, uLong sourceLen,
  916                                   int level));
  917 /*
  918      Compresses the source buffer into the destination buffer. The level
  919    parameter has the same meaning as in deflateInit.  sourceLen is the byte
  920    length of the source buffer. Upon entry, destLen is the total size of the
  921    destination buffer, which must be at least 0.1% larger than sourceLen plus
  922    12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
  923 
  924      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  925    memory, Z_BUF_ERROR if there was not enough room in the output buffer,
  926    Z_STREAM_ERROR if the level parameter is invalid.
  927 */
  928 
  929 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
  930                                    const Bytef *source, uLong sourceLen));
  931 /*
  932      Decompresses the source buffer into the destination buffer.  sourceLen is
  933    the byte length of the source buffer. Upon entry, destLen is the total
  934    size of the destination buffer, which must be large enough to hold the
  935    entire uncompressed data. (The size of the uncompressed data must have
  936    been saved previously by the compressor and transmitted to the decompressor
  937    by some mechanism outside the scope of this compression library.)
  938    Upon exit, destLen is the actual size of the compressed buffer.
  939      This function can be used to decompress a whole file at once if the
  940    input file is mmap'ed.
  941 
  942      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
  943    enough memory, Z_BUF_ERROR if there was not enough room in the output
  944    buffer, or Z_DATA_ERROR if the input data was corrupted.
  945 */
  946 
  947 
  948 typedef voidp gzFile;
  949 
  950 ZEXTERN gzFile ZEXPORT gzopen  OF((const char *path, const char *mode));
  951 /*
  952      Opens a gzip (.gz) file for reading or writing. The mode parameter
  953    is as in fopen ("rb" or "wb") but can also include a compression level
  954    ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
  955    Huffman only compression as in "wb1h". (See the description
  956    of deflateInit2 for more information about the strategy parameter.)
  957 
  958      gzopen can be used to read a file which is not in gzip format; in this
  959    case gzread will directly read from the file without decompression.
  960 
  961      gzopen returns NULL if the file could not be opened or if there was
  962    insufficient memory to allocate the (de)compression state; errno
  963    can be checked to distinguish the two cases (if errno is zero, the
  964    zlib error is Z_MEM_ERROR).  */
  965 
  966 ZEXTERN gzFile ZEXPORT gzdopen  OF((int fd, const char *mode));
  967 /*
  968      gzdopen() associates a gzFile with the file descriptor fd.  File
  969    descriptors are obtained from calls like open, dup, creat, pipe or
  970    fileno (in the file has been previously opened with fopen).
  971    The mode parameter is as in gzopen.
  972      The next call of gzclose on the returned gzFile will also close the
  973    file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
  974    descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
  975      gzdopen returns NULL if there was insufficient memory to allocate
  976    the (de)compression state.
  977 */
  978 
  979 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
  980 /*
  981      Dynamically update the compression level or strategy. See the description
  982    of deflateInit2 for the meaning of these parameters.
  983      gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
  984    opened for writing.
  985 */
  986 
  987 ZEXTERN int ZEXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));
  988 /*
  989      Reads the given number of uncompressed bytes from the compressed file.
  990    If the input file was not in gzip format, gzread copies the given number
  991    of bytes into the buffer.
  992      gzread returns the number of uncompressed bytes actually read (0 for
  993    end of file, -1 for error). */
  994 
  995 ZEXTERN int ZEXPORT    gzwrite OF((gzFile file, 
  996                                    const voidp buf, unsigned len));
  997 /*
  998      Writes the given number of uncompressed bytes into the compressed file.
  999    gzwrite returns the number of uncompressed bytes actually written
 1000    (0 in case of error).
 1001 */
 1002 
 1003 ZEXTERN int ZEXPORTVA   gzprintf OF((gzFile file, const char *format, ...));
 1004 /*
 1005      Converts, formats, and writes the args to the compressed file under
 1006    control of the format string, as in fprintf. gzprintf returns the number of
 1007    uncompressed bytes actually written (0 in case of error).
 1008 */
 1009 
 1010 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
 1011 /*
 1012       Writes the given null-terminated string to the compressed file, excluding
 1013    the terminating null character.
 1014       gzputs returns the number of characters written, or -1 in case of error.
 1015 */
 1016 
 1017 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
 1018 /*
 1019       Reads bytes from the compressed file until len-1 characters are read, or
 1020    a newline character is read and transferred to buf, or an end-of-file
 1021    condition is encountered.  The string is then terminated with a null
 1022    character.
 1023       gzgets returns buf, or Z_NULL in case of error.
 1024 */
 1025 
 1026 ZEXTERN int ZEXPORT    gzputc OF((gzFile file, int c));
 1027 /*
 1028       Writes c, converted to an unsigned char, into the compressed file.
 1029    gzputc returns the value that was written, or -1 in case of error.
 1030 */
 1031 
 1032 ZEXTERN int ZEXPORT    gzgetc OF((gzFile file));
 1033 /*
 1034       Reads one byte from the compressed file. gzgetc returns this byte
 1035    or -1 in case of end of file or error.
 1036 */
 1037 
 1038 ZEXTERN int ZEXPORT    gzflush OF((gzFile file, int flush));
 1039 /*
 1040      Flushes all pending output into the compressed file. The parameter
 1041    flush is as in the deflate() function. The return value is the zlib
 1042    error number (see function gzerror below). gzflush returns Z_OK if
 1043    the flush parameter is Z_FINISH and all output could be flushed.
 1044      gzflush should be called only when strictly necessary because it can
 1045    degrade compression.
 1046 */
 1047 
 1048 ZEXTERN z_off_t ZEXPORT    gzseek OF((gzFile file,
 1049                                       z_off_t offset, int whence));
 1050 /* 
 1051       Sets the starting position for the next gzread or gzwrite on the
 1052    given compressed file. The offset represents a number of bytes in the
 1053    uncompressed data stream. The whence parameter is defined as in lseek(2);
 1054    the value SEEK_END is not supported.
 1055      If the file is opened for reading, this function is emulated but can be
 1056    extremely slow. If the file is opened for writing, only forward seeks are
 1057    supported; gzseek then compresses a sequence of zeroes up to the new
 1058    starting position.
 1059 
 1060       gzseek returns the resulting offset location as measured in bytes from
 1061    the beginning of the uncompressed stream, or -1 in case of error, in
 1062    particular if the file is opened for writing and the new starting position
 1063    would be before the current position.
 1064 */
 1065 
 1066 ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
 1067 /*
 1068      Rewinds the given file. This function is supported only for reading.
 1069 
 1070    gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
 1071 */
 1072 
 1073 ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
 1074 /*
 1075      Returns the starting position for the next gzread or gzwrite on the
 1076    given compressed file. This position represents a number of bytes in the
 1077    uncompressed data stream.
 1078 
 1079    gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
 1080 */
 1081 
 1082 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
 1083 /*
 1084      Returns 1 when EOF has previously been detected reading the given
 1085    input stream, otherwise zero.
 1086 */
 1087 
 1088 ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
 1089 /*
 1090      Flushes all pending output if necessary, closes the compressed file
 1091    and deallocates all the (de)compression state. The return value is the zlib
 1092    error number (see function gzerror below).
 1093 */
 1094 
 1095 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
 1096 /*
 1097      Returns the error message for the last error which occurred on the
 1098    given compressed file. errnum is set to zlib error number. If an
 1099    error occurred in the file system and not in the compression library,
 1100    errnum is set to Z_ERRNO and the application may consult errno
 1101    to get the exact error code.
 1102 */
 1103 
 1104                         /* checksum functions */
 1105 
 1106 /*
 1107      These functions are not related to compression but are exported
 1108    anyway because they might be useful in applications using the
 1109    compression library.
 1110 */
 1111 
 1112 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
 1113 
 1114 /*
 1115      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
 1116    return the updated checksum. If buf is NULL, this function returns
 1117    the required initial value for the checksum.
 1118    An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
 1119    much faster. Usage example:
 1120 
 1121      uLong adler = adler32(0L, Z_NULL, 0);
 1122 
 1123      while (read_buffer(buffer, length) != EOF) {
 1124        adler = adler32(adler, buffer, length);
 1125      }
 1126      if (adler != original_adler) error();
 1127 */
 1128 
 1129 ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
 1130 /*
 1131      Update a running crc with the bytes buf[0..len-1] and return the updated
 1132    crc. If buf is NULL, this function returns the required initial value
 1133    for the crc. Pre- and post-conditioning (one's complement) is performed
 1134    within this function so it shouldn't be done by the application.
 1135    Usage example:
 1136 
 1137      uLong crc = crc32(0L, Z_NULL, 0);
 1138 
 1139      while (read_buffer(buffer, length) != EOF) {
 1140        crc = crc32(crc, buffer, length);
 1141      }
 1142      if (crc != original_crc) error();
 1143 */
 1144 
 1145 
 1146                         /* various hacks, don't look :) */
 1147 
 1148 /* deflateInit and inflateInit are macros to allow checking the zlib version
 1149  * and the compiler's view of z_stream:
 1150  */
 1151 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
 1152                                      const char *version, int stream_size));
 1153 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
 1154                                      const char *version, int stream_size));
 1155 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
 1156                                       int windowBits, int memLevel,
 1157                                       int strategy, const char *version,
 1158                                       int stream_size));
 1159 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
 1160                                       const char *version, int stream_size));
 1161 #define deflateInit(strm, level) \
 1162         deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
 1163 #define inflateInit(strm) \
 1164         inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
 1165 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
 1166         deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
 1167                       (strategy),           ZLIB_VERSION, sizeof(z_stream))
 1168 #define inflateInit2(strm, windowBits) \
 1169         inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
 1170 
 1171 
 1172 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
 1173     struct internal_state {int dummy;}; /* hack for buggy compilers */
 1174 #endif
 1175 
 1176 ZEXTERN const char   * ZEXPORT zError           OF((int err));
 1177 ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp z));
 1178 ZEXTERN const uLongf * ZEXPORT get_crc_table    OF((void));
 1179 
 1180 #ifdef __cplusplus
 1181 }
 1182 #endif
 1183 
 1184 #endif /* !KERNEL || __APPLE_API_PRIVATE */
 1185 #endif /* _ZLIB_H */
 1186 /* --- zlib.h */

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