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

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    1 /* $NetBSD: zlib.h,v 1.12 2006/01/14 20:17:12 christos Exp $ */
    2 
    3 /* zlib.h -- interface of the 'zlib' general purpose compression library
    4   version 1.1.4, March 11th, 2002
    5 
    6   Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler
    7 
    8   This software is provided 'as-is', without any express or implied
    9   warranty.  In no event will the authors be held liable for any damages
   10   arising from the use of this software.
   11 
   12   Permission is granted to anyone to use this software for any purpose,
   13   including commercial applications, and to alter it and redistribute it
   14   freely, subject to the following restrictions:
   15 
   16   1. The origin of this software must not be misrepresented; you must not
   17      claim that you wrote the original software. If you use this software
   18      in a product, an acknowledgment in the product documentation would be
   19      appreciated but is not required.
   20   2. Altered source versions must be plainly marked as such, and must not be
   21      misrepresented as being the original software.
   22   3. This notice may not be removed or altered from any source distribution.
   23 
   24   Jean-loup Gailly        Mark Adler
   25   jloup@gzip.org          madler@alumni.caltech.edu
   26 
   27 
   28   The data format used by the zlib library is described by RFCs (Request for
   29   Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
   30   (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
   31 */
   32 
   33 #ifndef _NET_ZLIB_H_
   34 #define _NET_ZLIB_H_
   35 
   36 #ifdef __NetBSD__
   37 #include <sys/cdefs.h>
   38 #endif
   39 
   40 /* +++ zconf.h */
   41 /* zconf.h -- configuration of the zlib compression library
   42  * Copyright (C) 1995-2002 Jean-loup Gailly.
   43  * For conditions of distribution and use, see copyright notice in zlib.h
   44  */
   45 
   46 /* @(#) $Id: zlib.h,v 1.12 2006/01/14 20:17:12 christos Exp $ */
   47 
   48 #ifndef ZCONF_H
   49 #define ZCONF_H
   50 
   51 /*
   52  * Warning:  This file pollutes the user's namespace with:
   53  *      Byte Bytef EXPORT FAR OF STDC
   54  *  charf intf uInt uIntf uLong uLonf
   55  * Programs using this library appear to expect those...
   56  */
   57 
   58 #include <sys/types.h>
   59 
   60 /*
   61  * If you *really* need a unique prefix for all types and library functions,
   62  * compile with -DZ_PREFIX. The "standard" zlib should be compiled without it.
   63  */
   64 #ifdef Z_PREFIX
   65 #  define deflateInit_  z_deflateInit_
   66 #  define deflate       z_deflate
   67 #  define deflateEnd    z_deflateEnd
   68 #  define inflateInit_  z_inflateInit_
   69 #  define inflate       z_inflate
   70 #  define inflateEnd    z_inflateEnd
   71 #  define deflateInit2_ z_deflateInit2_
   72 #  define deflateSetDictionary z_deflateSetDictionary
   73 #  define deflateCopy   z_deflateCopy
   74 #  define deflateReset  z_deflateReset
   75 #  define deflateParams z_deflateParams
   76 #  define inflateInit2_ z_inflateInit2_
   77 #  define inflateSetDictionary z_inflateSetDictionary
   78 #  define inflateSync   z_inflateSync
   79 #  define inflateSyncPoint z_inflateSyncPoint
   80 #  define inflateReset  z_inflateReset
   81 #  define compress      z_compress
   82 #  define compress2     z_compress2
   83 #  define uncompress    z_uncompress
   84 #  define adler32       z_adler32
   85 #  define crc32         z_crc32
   86 #  define get_crc_table z_get_crc_table
   87 
   88 #  define Byte          z_Byte
   89 #  define uInt          z_uInt
   90 #  define uLong         z_uLong
   91 #  define Bytef         z_Bytef
   92 #  define charf         z_charf
   93 #  define intf          z_intf
   94 #  define uIntf         z_uIntf
   95 #  define uLongf        z_uLongf
   96 #  define voidpf        z_voidpf
   97 #  define voidp         z_voidp
   98 #endif
   99 
  100 #ifndef __32BIT__
  101 /* Don't be alarmed; this just means we have at least 32-bits */
  102 #  define __32BIT__
  103 #endif
  104 
  105 /*
  106  * Compile with -DMAXSEG_64K if the alloc function cannot allocate more
  107  * than 64k bytes at a time (needed on systems with 16-bit int).
  108  */
  109 #if defined(MSDOS) && !defined(__32BIT__)
  110 #  define MAXSEG_64K
  111 #endif
  112 
  113 #if 0
  114 /* XXX: Are there machines where we should define this?  m68k? */
  115 #  define UNALIGNED_OK
  116 #endif
  117 
  118 #if (defined(__STDC__) || defined(__cplusplus)) && !defined(STDC)
  119 /* XXX: Look out - this is used in zutil.h and elsewhere... */
  120 #  define STDC
  121 #endif
  122 #if defined(__STDC__) || defined(__cplusplus) || defined(__OS2__)
  123 #  ifndef STDC
  124 #    define STDC
  125 #  endif
  126 #endif
  127 
  128 #ifndef STDC
  129 #  ifndef const
  130 #    define const
  131 #  endif
  132 #endif
  133 
  134 /* Some Mac compilers merge all .h files incorrectly: */
  135 #if defined(__MWERKS__) || defined(applec) ||defined(THINK_C) ||defined(__SC__)
  136 #  define NO_DUMMY_DECL
  137 #endif
  138 
  139 /* Old Borland C incorrectly complains about missing returns: */
  140 #if defined(__BORLANDC__) && (__BORLANDC__ < 0x500)
  141 #  define NEED_DUMMY_RETURN
  142 #endif
  143 
  144 
  145 /* Maximum value for memLevel in deflateInit2 */
  146 #ifndef MAX_MEM_LEVEL
  147 #  ifdef MAXSEG_64K
  148 #    define MAX_MEM_LEVEL 8
  149 #  else
  150 #    define MAX_MEM_LEVEL 9
  151 #  endif
  152 #endif
  153 
  154 /* Maximum value for windowBits in deflateInit2 and inflateInit2.
  155  * WARNING: reducing MAX_WBITS makes minigzip unable to extract .gz files
  156  * created by gzip. (Files created by minigzip can still be extracted by
  157  * gzip.)
  158  */
  159 #ifndef MAX_WBITS
  160 #  define MAX_WBITS   15 /* 32K LZ77 window */
  161 #endif
  162 
  163 /* The memory requirements for deflate are (in bytes):
  164             (1 << (windowBits+2)) +  (1 << (memLevel+9))
  165  that is: 128K for windowBits=15  +  128K for memLevel = 8  (default values)
  166  plus a few kilobytes for small objects. For example, if you want to reduce
  167  the default memory requirements from 256K to 128K, compile with
  168      make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
  169  Of course this will generally degrade compression (there's no free lunch).
  170 
  171    The memory requirements for inflate are (in bytes) 1 << windowBits
  172  that is, 32K for windowBits=15 (default value) plus a few kilobytes
  173  for small objects.
  174 */
  175 
  176                         /* Type declarations */
  177 
  178 #ifndef __P /* function prototypes */
  179 #  ifdef STDC
  180 #    define __P(args)  args
  181 #  else
  182 #    define __P(args)  ()
  183 #  endif
  184 #endif
  185 
  186 /* The following definitions for FAR are needed only for MSDOS mixed
  187  * model programming (small or medium model with some far allocations).
  188  * This was tested only with MSC; for other MSDOS compilers you may have
  189  * to define NO_MEMCPY in zutil.h.  If you don't need the mixed model,
  190  * just define FAR to be empty.
  191  */
  192 #if (defined(M_I86SM) || defined(M_I86MM)) && !defined(__32BIT__)
  193    /* MSC small or medium model */
  194 #  define SMALL_MEDIUM
  195 #  ifdef _MSC_VER
  196 #    define FAR _far
  197 #  else
  198 #    define FAR far
  199 #  endif
  200 #endif
  201 #if defined(__BORLANDC__) && (defined(__SMALL__) || defined(__MEDIUM__))
  202 #  ifndef __32BIT__
  203 #    define SMALL_MEDIUM
  204 #    define FAR _far
  205 #  endif
  206 #endif
  207 
  208 /* Compile with -DZLIB_DLL for Windows DLL support */
  209 #if defined(ZLIB_DLL)
  210 #  if defined(_WINDOWS) || defined(WINDOWS)
  211 #    ifdef FAR
  212 #      undef FAR
  213 #    endif
  214 #    include <windows.h>
  215 #    define ZEXPORT  WINAPI
  216 #    ifdef WIN32
  217 #      define ZEXPORTVA  WINAPIV
  218 #    else
  219 #      define ZEXPORTVA  FAR _cdecl _export
  220 #    endif
  221 #  endif
  222 #  if defined (__BORLANDC__)
  223 #    if (__BORLANDC__ >= 0x0500) && defined (WIN32)
  224 #      include <windows.h>
  225 #      define ZEXPORT __declspec(dllexport) WINAPI
  226 #      define ZEXPORTRVA __declspec(dllexport) WINAPIV
  227 #    else
  228 #      if defined (_Windows) && defined (__DLL__)
  229 #        define ZEXPORT _export
  230 #        define ZEXPORTVA _export
  231 #      endif
  232 #    endif
  233 #  endif
  234 #endif
  235 
  236 #if defined (__BEOS__)
  237 #  if defined (ZLIB_DLL)
  238 #    define ZEXTERN extern __declspec(dllexport)
  239 #  else
  240 #    define ZEXTERN extern __declspec(dllimport)
  241 #  endif
  242 #endif
  243 
  244 #ifndef ZEXPORT
  245 #  define ZEXPORT
  246 #endif
  247 #ifndef ZEXPORTVA
  248 #  define ZEXPORTVA
  249 #endif
  250 #ifndef ZEXTERN
  251 #  define ZEXTERN extern
  252 #endif
  253 
  254 #ifndef FAR
  255 #   define FAR
  256 #endif
  257 
  258 #if !defined(MACOS) && !defined(TARGET_OS_MAC)
  259 typedef unsigned char  Byte;  /* 8 bits */
  260 #endif
  261 typedef unsigned int   uInt;  /* 16 bits or more */
  262 typedef unsigned long  uLong; /* 32 bits or more */
  263 
  264 #ifdef SMALL_MEDIUM
  265    /* Borland C/C++ and some old MSC versions ignore FAR inside typedef */
  266 #  define Bytef Byte FAR
  267 #else
  268    typedef Byte  FAR Bytef;
  269 #endif
  270 typedef char  FAR charf;
  271 typedef int   FAR intf;
  272 typedef uInt  FAR uIntf;
  273 typedef uLong FAR uLongf;
  274 
  275 #ifdef STDC
  276    typedef void FAR *voidpf;
  277    typedef void     *voidp;
  278 #else
  279    typedef Byte FAR *voidpf;
  280    typedef Byte     *voidp;
  281 #endif
  282 
  283 #if (defined(HAVE_UNISTD_H) || defined(__NetBSD__)) && !defined(_KERNEL)
  284 #  include <sys/types.h> /* for off_t */
  285 #  include <unistd.h>    /* for SEEK_* and off_t */
  286 #  define z_off_t  off_t
  287 #endif
  288 #ifndef SEEK_SET
  289 #  define SEEK_SET        0       /* Seek from beginning of file.  */
  290 #  define SEEK_CUR        1       /* Seek from current position.  */
  291 #  define SEEK_END        2       /* Set file pointer to EOF plus "offset" */
  292 #endif
  293 #ifndef z_off_t
  294 #  define  z_off_t long
  295 #endif
  296 
  297 /* MVS linker does not support external names larger than 8 bytes */
  298 #if defined(__MVS__)
  299 #   pragma map(deflateInit_,"DEIN")
  300 #   pragma map(deflateInit2_,"DEIN2")
  301 #   pragma map(deflateEnd,"DEEND")
  302 #   pragma map(inflateInit_,"ININ")
  303 #   pragma map(inflateInit2_,"ININ2")
  304 #   pragma map(inflateEnd,"INEND")
  305 #   pragma map(inflateSync,"INSY")
  306 #   pragma map(inflateSetDictionary,"INSEDI")
  307 #   pragma map(inflate_blocks,"INBL")
  308 #   pragma map(inflate_blocks_new,"INBLNE")
  309 #   pragma map(inflate_blocks_free,"INBLFR")
  310 #   pragma map(inflate_blocks_reset,"INBLRE")
  311 #   pragma map(inflate_codes_free,"INCOFR")
  312 #   pragma map(inflate_codes,"INCO")
  313 #   pragma map(inflate_fast,"INFA")
  314 #   pragma map(inflate_flush,"INFLU")
  315 #   pragma map(inflate_mask,"INMA")
  316 #   pragma map(inflate_set_dictionary,"INSEDI2")
  317 #   pragma map(inflate_copyright,"INCOPY")
  318 #   pragma map(inflate_trees_bits,"INTRBI")
  319 #   pragma map(inflate_trees_dynamic,"INTRDY")
  320 #   pragma map(inflate_trees_fixed,"INTRFI")
  321 #   pragma map(inflate_trees_free,"INTRFR")
  322 #endif
  323 
  324 #endif /* !ZCONF_H */
  325 /* --- zconf.h */
  326 
  327 #ifndef ZLIB_H
  328 #define ZLIB_H
  329 #ifdef __cplusplus
  330 extern "C" {
  331 #endif
  332 
  333 #define ZLIB_VERSION "1.1.4"
  334 
  335 /*
  336      The 'zlib' compression library provides in-memory compression and
  337   decompression functions, including integrity checks of the uncompressed
  338   data.  This version of the library supports only one compression method
  339   (deflation) but other algorithms will be added later and will have the same
  340   stream interface.
  341 
  342      Compression can be done in a single step if the buffers are large
  343   enough (for example if an input file is mmap'ed), or can be done by
  344   repeated calls of the compression function.  In the latter case, the
  345   application must provide more input and/or consume the output
  346   (providing more output space) before each call.
  347 
  348      The library also supports reading and writing files in gzip (.gz) format
  349   with an interface similar to that of stdio.
  350 
  351      The library does not install any signal handler. The decoder checks
  352   the consistency of the compressed data, so the library should never
  353   crash even in case of corrupted input.
  354 */
  355 
  356 typedef voidpf (*alloc_func) __P((voidpf, uInt, uInt));
  357 typedef void   (*free_func)  __P((voidpf, voidpf));
  358 
  359 struct internal_state;
  360 
  361 typedef struct z_stream_s {
  362     Bytef    *next_in;  /* next input byte */
  363     uInt     avail_in;  /* number of bytes available at next_in */
  364     uLong    total_in;  /* total nb of input bytes read so far */
  365 
  366     Bytef    *next_out; /* next output byte should be put there */
  367     uInt     avail_out; /* remaining free space at next_out */
  368     uLong    total_out; /* total nb of bytes output so far */
  369 
  370     const char *msg;      /* last error message, NULL if no error */
  371     struct internal_state FAR *state; /* not visible by applications */
  372 
  373     alloc_func zalloc;  /* used to allocate the internal state */
  374     free_func  zfree;   /* used to free the internal state */
  375     voidpf     opaque;  /* private data object passed to zalloc and zfree */
  376 
  377     int     data_type;  /* best guess about the data type: ascii or binary */
  378     uLong   adler;      /* adler32 value of the uncompressed data */
  379     uLong   reserved;   /* reserved for future use */
  380 } z_stream;
  381 
  382 typedef z_stream FAR *z_streamp;
  383 
  384 /*
  385    The application must update next_in and avail_in when avail_in has
  386    dropped to zero. It must update next_out and avail_out when avail_out
  387    has dropped to zero. The application must initialize zalloc, zfree and
  388    opaque before calling the init function. All other fields are set by the
  389    compression library and must not be updated by the application.
  390 
  391    The opaque value provided by the application will be passed as the first
  392    parameter for calls of zalloc and zfree. This can be useful for custom
  393    memory management. The compression library attaches no meaning to the
  394    opaque value.
  395 
  396    zalloc must return Z_NULL if there is not enough memory for the object.
  397    If zlib is used in a multi-threaded application, zalloc and zfree must be
  398    thread safe.
  399 
  400    On 16-bit systems, the functions zalloc and zfree must be able to allocate
  401    exactly 65536 bytes, but will not be required to allocate more than this
  402    if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
  403    pointers returned by zalloc for objects of exactly 65536 bytes *must*
  404    have their offset normalized to zero. The default allocation function
  405    provided by this library ensures this (see zutil.c). To reduce memory
  406    requirements and avoid any allocation of 64K objects, at the expense of
  407    compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
  408 
  409    The fields total_in and total_out can be used for statistics or
  410    progress reports. After compression, total_in holds the total size of
  411    the uncompressed data and may be saved for use in the decompressor
  412    (particularly if the decompressor wants to decompress everything in
  413    a single step).
  414 */
  415 
  416                         /* constants */
  417 
  418 #define Z_NO_FLUSH      0
  419 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
  420 #define Z_PACKET_FLUSH  2
  421 #define Z_SYNC_FLUSH    3
  422 #define Z_FULL_FLUSH    4
  423 #define Z_FINISH        5
  424 /* Allowed flush values; see deflate() below for details */
  425 
  426 #define Z_OK            0
  427 #define Z_STREAM_END    1
  428 #define Z_NEED_DICT     2
  429 #define Z_ERRNO        (-1)
  430 #define Z_STREAM_ERROR (-2)
  431 #define Z_DATA_ERROR   (-3)
  432 #define Z_MEM_ERROR    (-4)
  433 #define Z_BUF_ERROR    (-5)
  434 #define Z_VERSION_ERROR (-6)
  435 /* Return codes for the compression/decompression functions. Negative
  436  * values are errors, positive values are used for special but normal events.
  437  */
  438 
  439 #define Z_NO_COMPRESSION         0
  440 #define Z_BEST_SPEED             1
  441 #define Z_BEST_COMPRESSION       9
  442 #define Z_DEFAULT_COMPRESSION  (-1)
  443 /* compression levels */
  444 
  445 #define Z_FILTERED            1
  446 #define Z_HUFFMAN_ONLY        2
  447 #define Z_DEFAULT_STRATEGY    0
  448 /* compression strategy; see deflateInit2() below for details */
  449 
  450 #define Z_BINARY   0
  451 #define Z_ASCII    1
  452 #define Z_UNKNOWN  2
  453 /* Possible values of the data_type field */
  454 
  455 #define Z_DEFLATED   8
  456 /* The deflate compression method (the only one supported in this version) */
  457 
  458 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
  459 
  460 #define zlib_version zlibVersion()
  461 /* for compatibility with versions < 1.0.2 */
  462 
  463                         /* basic functions */
  464 
  465 ZEXTERN const char * ZEXPORT zlibVersion __P((void));
  466 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
  467    If the first character differs, the library code actually used is
  468    not compatible with the zlib.h header file used by the application.
  469    This check is automatically made by deflateInit and inflateInit.
  470  */
  471 
  472 /*
  473 ZEXTERN int ZEXPORT deflateInit __P((z_streamp, int));
  474 
  475      Initializes the internal stream state for compression. The fields
  476    zalloc, zfree and opaque must be initialized before by the caller.
  477    If zalloc and zfree are set to Z_NULL, deflateInit updates them to
  478    use default allocation functions.
  479 
  480      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
  481    1 gives best speed, 9 gives best compression, 0 gives no compression at
  482    all (the input data is simply copied a block at a time).
  483    Z_DEFAULT_COMPRESSION requests a default compromise between speed and
  484    compression (currently equivalent to level 6).
  485 
  486      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
  487    enough memory, Z_STREAM_ERROR if level is not a valid compression level,
  488    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
  489    with the version assumed by the caller (ZLIB_VERSION).
  490    msg is set to null if there is no error message.  deflateInit does not
  491    perform any compression: this will be done by deflate().
  492 */
  493 
  494 
  495 ZEXTERN int ZEXPORT deflate __P((z_streamp, int));
  496 /*
  497     deflate compresses as much data as possible, and stops when the input
  498   buffer becomes empty or the output buffer becomes full. It may introduce some
  499   output latency (reading input without producing any output) except when
  500   forced to flush.
  501 
  502     The detailed semantics are as follows. deflate performs one or both of the
  503   following actions:
  504 
  505   - Compress more input starting at next_in and update next_in and avail_in
  506     accordingly. If not all input can be processed (because there is not
  507     enough room in the output buffer), next_in and avail_in are updated and
  508     processing will resume at this point for the next call of deflate().
  509 
  510   - Provide more output starting at next_out and update next_out and avail_out
  511     accordingly. This action is forced if the parameter flush is non zero.
  512     Forcing flush frequently degrades the compression ratio, so this parameter
  513     should be set only when necessary (in interactive applications).
  514     Some output may be provided even if flush is not set.
  515 
  516   Before the call of deflate(), the application should ensure that at least
  517   one of the actions is possible, by providing more input and/or consuming
  518   more output, and updating avail_in or avail_out accordingly; avail_out
  519   should never be zero before the call. The application can consume the
  520   compressed output when it wants, for example when the output buffer is full
  521   (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
  522   and with zero avail_out, it must be called again after making room in the
  523   output buffer because there might be more output pending.
  524 
  525     If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
  526   flushed to the output buffer and the output is aligned on a byte boundary, so
  527   that the decompressor can get all input data available so far. (In particular
  528   avail_in is zero after the call if enough output space has been provided
  529   before the call.)  Flushing may degrade compression for some compression
  530   algorithms and so it should be used only when necessary.
  531 
  532     If flush is set to Z_FULL_FLUSH, all output is flushed as with
  533   Z_SYNC_FLUSH, and the compression state is reset so that decompression can
  534   restart from this point if previous compressed data has been damaged or if
  535   random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
  536   the compression.
  537 
  538     If deflate returns with avail_out == 0, this function must be called again
  539   with the same value of the flush parameter and more output space (updated
  540   avail_out), until the flush is complete (deflate returns with non-zero
  541   avail_out).
  542 
  543     If the parameter flush is set to Z_PACKET_FLUSH, the compression
  544   block is terminated, and a zero-length stored block is output,
  545   omitting the length bytes (the effect of this is that the 3-bit type
  546   code 000 for a stored block is output, and the output is then
  547   byte-aligned).  This is designed for use at the end of a PPP packet.
  548 
  549 
  550     If the parameter flush is set to Z_FINISH, pending input is processed,
  551   pending output is flushed and deflate returns with Z_STREAM_END if there
  552   was enough output space; if deflate returns with Z_OK, this function must be
  553   called again with Z_FINISH and more output space (updated avail_out) but no
  554   more input data, until it returns with Z_STREAM_END or an error. After
  555   deflate has returned Z_STREAM_END, the only possible operations on the
  556   stream are deflateReset or deflateEnd.
  557 
  558     Z_FINISH can be used immediately after deflateInit if all the compression
  559   is to be done in a single step. In this case, avail_out must be at least
  560   0.1% larger than avail_in plus 12 bytes.  If deflate does not return
  561   Z_STREAM_END, then it must be called again as described above.
  562 
  563     deflate() sets strm->adler to the adler32 checksum of all input read
  564   so far (that is, total_in bytes).
  565 
  566     deflate() may update data_type if it can make a good guess about
  567   the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
  568   binary. This field is only for information purposes and does not affect
  569   the compression algorithm in any manner.
  570 
  571     deflate() returns Z_OK if some progress has been made (more input
  572   processed or more output produced), Z_STREAM_END if all input has been
  573   consumed and all output has been produced (only when flush is set to
  574   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
  575   if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
  576   (for example avail_in or avail_out was zero).
  577 */
  578 
  579 
  580 ZEXTERN int ZEXPORT deflateEnd __P((z_streamp));
  581 /*
  582      All dynamically allocated data structures for this stream are freed.
  583    This function discards any unprocessed input and does not flush any
  584    pending output.
  585 
  586      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
  587    stream state was inconsistent, Z_DATA_ERROR if the stream was freed
  588    prematurely (some input or output was discarded). In the error case,
  589    msg may be set but then points to a static string (which must not be
  590    deallocated).
  591 */
  592 
  593 
  594 /*
  595 ZEXTERN int ZEXPORT inflateInit __P((z_streamp));
  596 
  597      Initializes the internal stream state for decompression. The fields
  598    next_in, avail_in, zalloc, zfree and opaque must be initialized before by
  599    the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
  600    value depends on the compression method), inflateInit determines the
  601    compression method from the zlib header and allocates all data structures
  602    accordingly; otherwise the allocation will be deferred to the first call of
  603    inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
  604    use default allocation functions.
  605 
  606      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
  607    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
  608    version assumed by the caller.  msg is set to null if there is no error
  609    message. inflateInit does not perform any decompression apart from reading
  610    the zlib header if present: this will be done by inflate().  (So next_in and
  611    avail_in may be modified, but next_out and avail_out are unchanged.)
  612 */
  613 
  614 
  615 ZEXTERN int ZEXPORT inflate __P((z_streamp, int));
  616 /*
  617     inflate decompresses as much data as possible, and stops when the input
  618   buffer becomes empty or the output buffer becomes full. It may some
  619   introduce some output latency (reading input without producing any output)
  620   except when forced to flush.
  621 
  622   The detailed semantics are as follows. inflate performs one or both of the
  623   following actions:
  624 
  625   - Decompress more input starting at next_in and update next_in and avail_in
  626     accordingly. If not all input can be processed (because there is not
  627     enough room in the output buffer), next_in is updated and processing
  628     will resume at this point for the next call of inflate().
  629 
  630   - Provide more output starting at next_out and update next_out and avail_out
  631     accordingly.  inflate() provides as much output as possible, until there
  632     is no more input data or no more space in the output buffer (see below
  633     about the flush parameter).
  634 
  635   Before the call of inflate(), the application should ensure that at least
  636   one of the actions is possible, by providing more input and/or consuming
  637   more output, and updating the next_* and avail_* values accordingly.
  638   The application can consume the uncompressed output when it wants, for
  639   example when the output buffer is full (avail_out == 0), or after each
  640   call of inflate(). If inflate returns Z_OK and with zero avail_out, it
  641   must be called again after making room in the output buffer because there
  642   might be more output pending.
  643 
  644     If the parameter flush is set to Z_SYNC_FLUSH or Z_PACKET_FLUSH,
  645   inflate flushes as much output as possible to the output buffer. The
  646   flushing behavior of inflate is not specified for values of the flush
  647   parameter other than Z_SYNC_FLUSH, Z_PACKET_FLUSH or Z_FINISH, but the
  648   current implementation actually flushes as much output as possible
  649   anyway. For Z_PACKET_FLUSH, inflate checks that once all the input data
  650   has been consumed, it is expecting to see the length field of a stored
  651   block; if not, it returns Z_DATA_ERROR.
  652 
  653     inflate() should normally be called until it returns Z_STREAM_END or an
  654   error. However if all decompression is to be performed in a single step
  655   (a single call of inflate), the parameter flush should be set to
  656   Z_FINISH. In this case all pending input is processed and all pending
  657   output is flushed; avail_out must be large enough to hold all the
  658   uncompressed data. (The size of the uncompressed data may have been saved
  659   by the compressor for this purpose.) The next operation on this stream must
  660   be inflateEnd to deallocate the decompression state. The use of Z_FINISH
  661   is never required, but can be used to inform inflate that a faster routine
  662   may be used for the single inflate() call.
  663 
  664      If a preset dictionary is needed at this point (see inflateSetDictionary
  665   below), inflate sets strm-adler to the adler32 checksum of the
  666   dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
  667   it sets strm->adler to the adler32 checksum of all output produced
  668   so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
  669   an error code as described below. At the end of the stream, inflate()
  670   checks that its computed adler32 checksum is equal to that saved by the
  671   compressor and returns Z_STREAM_END only if the checksum is correct.
  672 
  673     inflate() returns Z_OK if some progress has been made (more input processed
  674   or more output produced), Z_STREAM_END if the end of the compressed data has
  675   been reached and all uncompressed output has been produced, Z_NEED_DICT if a
  676   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
  677   corrupted (input stream not conforming to the zlib format or incorrect
  678   adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
  679   (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
  680   enough memory, Z_BUF_ERROR if no progress is possible or if there was not
  681   enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
  682   case, the application may then call inflateSync to look for a good
  683   compression block.
  684 */
  685 
  686 
  687 ZEXTERN int ZEXPORT inflateEnd __P((z_streamp));
  688 /*
  689      All dynamically allocated data structures for this stream are freed.
  690    This function discards any unprocessed input and does not flush any
  691    pending output.
  692 
  693      inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
  694    was inconsistent. In the error case, msg may be set but then points to a
  695    static string (which must not be deallocated).
  696 */
  697 
  698                         /* Advanced functions */
  699 
  700 /*
  701     The following functions are needed only in some special applications.
  702 */
  703 
  704 /*
  705 ZEXTERN int ZEXPORT deflateInit2 __P((z_streamp, int, int, int, int, int));
  706 
  707      This is another version of deflateInit with more compression options. The
  708    fields next_in, zalloc, zfree and opaque must be initialized before by
  709    the caller.
  710 
  711      The method parameter is the compression method. It must be Z_DEFLATED in
  712    this version of the library.
  713 
  714      The windowBits parameter is the base two logarithm of the window size
  715    (the size of the history buffer).  It should be in the range 8..15 for this
  716    version of the library. Larger values of this parameter result in better
  717    compression at the expense of memory usage. The default value is 15 if
  718    deflateInit is used instead.
  719 
  720      The memLevel parameter specifies how much memory should be allocated
  721    for the internal compression state. memLevel=1 uses minimum memory but
  722    is slow and reduces compression ratio; memLevel=9 uses maximum memory
  723    for optimal speed. The default value is 8. See zconf.h for total memory
  724    usage as a function of windowBits and memLevel.
  725 
  726      The strategy parameter is used to tune the compression algorithm. Use the
  727    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
  728    filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
  729    string match).  Filtered data consists mostly of small values with a
  730    somewhat random distribution. In this case, the compression algorithm is
  731    tuned to compress them better. The effect of Z_FILTERED is to force more
  732    Huffman coding and less string matching; it is somewhat intermediate
  733    between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
  734    the compression ratio but not the correctness of the compressed output even
  735    if it is not set appropriately.
  736 
  737       deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  738    memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
  739    method). msg is set to null if there is no error message.  deflateInit2 does
  740    not perform any compression: this will be done by deflate().
  741 */
  742 
  743 ZEXTERN int ZEXPORT deflateSetDictionary __P((z_streamp, const Bytef *, uInt));
  744 /*
  745      Initializes the compression dictionary from the given byte sequence
  746    without producing any compressed output. This function must be called
  747    immediately after deflateInit, deflateInit2 or deflateReset, before any
  748    call of deflate. The compressor and decompressor must use exactly the same
  749    dictionary (see inflateSetDictionary).
  750 
  751      The dictionary should consist of strings (byte sequences) that are likely
  752    to be encountered later in the data to be compressed, with the most commonly
  753    used strings preferably put towards the end of the dictionary. Using a
  754    dictionary is most useful when the data to be compressed is short and can be
  755    predicted with good accuracy; the data can then be compressed better than
  756    with the default empty dictionary.
  757 
  758      Depending on the size of the compression data structures selected by
  759    deflateInit or deflateInit2, a part of the dictionary may in effect be
  760    discarded, for example if the dictionary is larger than the window size in
  761    deflate or deflate2. Thus the strings most likely to be useful should be
  762    put at the end of the dictionary, not at the front.
  763 
  764      Upon return of this function, strm->adler is set to the Adler32 value
  765    of the dictionary; the decompressor may later use this value to determine
  766    which dictionary has been used by the compressor. (The Adler32 value
  767    applies to the whole dictionary even if only a subset of the dictionary is
  768    actually used by the compressor.)
  769 
  770      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
  771    parameter is invalid (such as NULL dictionary) or the stream state is
  772    inconsistent (for example if deflate has already been called for this stream
  773    or if the compression method is bsort). deflateSetDictionary does not
  774    perform any compression: this will be done by deflate().
  775 */
  776 
  777 ZEXTERN int ZEXPORT deflateCopy __P((z_streamp, z_streamp));
  778 /*
  779      Sets the destination stream as a complete copy of the source stream.
  780 
  781      This function can be useful when several compression strategies will be
  782    tried, for example when there are several ways of pre-processing the input
  783    data with a filter. The streams that will be discarded should then be freed
  784    by calling deflateEnd.  Note that deflateCopy duplicates the internal
  785    compression state which can be quite large, so this strategy is slow and
  786    can consume lots of memory.
  787 
  788      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
  789    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
  790    (such as zalloc being NULL). msg is left unchanged in both source and
  791    destination.
  792 */
  793 
  794 extern int inflateIncomp __P((z_stream *));
  795 /*
  796      This function adds the data at next_in (avail_in bytes) to the output
  797    history without performing any output.  There must be no pending output,
  798    and the decompressor must be expecting to see the start of a block.
  799    Calling this function is equivalent to decompressing a stored block
  800    containing the data at next_in (except that the data is not output).
  801 */
  802 
  803 ZEXTERN int ZEXPORT deflateReset __P((z_streamp));
  804 /*
  805      This function is equivalent to deflateEnd followed by deflateInit,
  806    but does not free and reallocate all the internal compression state.
  807    The stream will keep the same compression level and any other attributes
  808    that may have been set by deflateInit2.
  809 
  810       deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  811    stream state was inconsistent (such as zalloc or state being NULL).
  812 */
  813 
  814 ZEXTERN int ZEXPORT deflateParams __P((z_streamp, int, int));
  815 /*
  816      Dynamically update the compression level and compression strategy.  The
  817    interpretation of level and strategy is as in deflateInit2.  This can be
  818    used to switch between compression and straight copy of the input data, or
  819    to switch to a different kind of input data requiring a different
  820    strategy. If the compression level is changed, the input available so far
  821    is compressed with the old level (and may be flushed); the new level will
  822    take effect only at the next call of deflate().
  823 
  824      Before the call of deflateParams, the stream state must be set as for
  825    a call of deflate(), since the currently available input may have to
  826    be compressed and flushed. In particular, strm->avail_out must be non-zero.
  827 
  828      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
  829    stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
  830    if strm->avail_out was zero.
  831 */
  832 
  833 ZEXTERN int ZEXPORT deflateOutputPending __P((z_streamp));
  834 /*
  835      Returns the number of bytes of output which are immediately
  836    available from the compressor (i.e. without any further input
  837    or flush).
  838 */
  839 
  840 /*
  841 ZEXTERN int ZEXPORT inflateInit2 __P((z_streamp, int));
  842 
  843      This is another version of inflateInit with an extra parameter. The
  844    fields next_in, avail_in, zalloc, zfree and opaque must be initialized
  845    before by the caller.
  846 
  847      The windowBits parameter is the base two logarithm of the maximum window
  848    size (the size of the history buffer).  It should be in the range 8..15 for
  849    this version of the library. The default value is 15 if inflateInit is used
  850    instead. If a compressed stream with a larger window size is given as
  851    input, inflate() will return with the error code Z_DATA_ERROR instead of
  852    trying to allocate a larger window.
  853 
  854       inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  855    memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
  856    memLevel). msg is set to null if there is no error message.  inflateInit2
  857    does not perform any decompression apart from reading the zlib header if
  858    present: this will be done by inflate(). (So next_in and avail_in may be
  859    modified, but next_out and avail_out are unchanged.)
  860 */
  861 
  862 ZEXTERN int ZEXPORT inflateSetDictionary __P((z_streamp, const Bytef *, uInt));
  863 /*
  864      Initializes the decompression dictionary from the given uncompressed byte
  865    sequence. This function must be called immediately after a call of inflate
  866    if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
  867    can be determined from the Adler32 value returned by this call of
  868    inflate. The compressor and decompressor must use exactly the same
  869    dictionary (see deflateSetDictionary).
  870 
  871      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
  872    parameter is invalid (such as NULL dictionary) or the stream state is
  873    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
  874    expected one (incorrect Adler32 value). inflateSetDictionary does not
  875    perform any decompression: this will be done by subsequent calls of
  876    inflate().
  877 */
  878 
  879 ZEXTERN int ZEXPORT inflateSync __P((z_streamp));
  880 /*
  881     Skips invalid compressed data until a full flush point (see above the
  882   description of deflate with Z_FULL_FLUSH) can be found, or until all
  883   available input is skipped. No output is provided.
  884 
  885     inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
  886   if no more input was provided, Z_DATA_ERROR if no flush point has been found,
  887   or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
  888   case, the application may save the current current value of total_in which
  889   indicates where valid compressed data was found. In the error case, the
  890   application may repeatedly call inflateSync, providing more input each time,
  891   until success or end of the input data.
  892 */
  893 
  894 ZEXTERN int ZEXPORT inflateReset __P((z_streamp));
  895 /*
  896      This function is equivalent to inflateEnd followed by inflateInit,
  897    but does not free and reallocate all the internal decompression state.
  898    The stream will keep attributes that may have been set by inflateInit2.
  899 
  900       inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  901    stream state was inconsistent (such as zalloc or state being NULL).
  902 */
  903 
  904 
  905                         /* utility functions */
  906 
  907 /*
  908      The following utility functions are implemented on top of the
  909    basic stream-oriented functions. To simplify the interface, some
  910    default options are assumed (compression level and memory usage,
  911    standard memory allocation functions). The source code of these
  912    utility functions can easily be modified if you need special options.
  913 */
  914 
  915 ZEXTERN int ZEXPORT compress __P((Bytef *, uLongf *, const Bytef *, uLong));
  916 /*
  917      Compresses the source buffer into the destination buffer.  sourceLen is
  918    the byte length of the source buffer. Upon entry, destLen is the total
  919    size of the destination buffer, which must be at least 0.1% larger than
  920    sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
  921    compressed buffer.
  922      This function can be used to compress a whole file at once if the
  923    input file is mmap'ed.
  924      compress returns Z_OK if success, Z_MEM_ERROR if there was not
  925    enough memory, Z_BUF_ERROR if there was not enough room in the output
  926    buffer.
  927 */
  928 
  929 ZEXTERN int ZEXPORT compress2 __P((Bytef *, uLongf *, const Bytef *,
  930             uLong, int));
  931 /*
  932      Compresses the source buffer into the destination buffer. The level
  933    parameter has the same meaning as in deflateInit.  sourceLen is the byte
  934    length of the source buffer. Upon entry, destLen is the total size of the
  935    destination buffer, which must be at least 0.1% larger than sourceLen plus
  936    12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
  937 
  938      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  939    memory, Z_BUF_ERROR if there was not enough room in the output buffer,
  940    Z_STREAM_ERROR if the level parameter is invalid.
  941 */
  942 
  943 ZEXTERN int ZEXPORT uncompress __P((Bytef *, uLongf *, const Bytef *, uLong));
  944 /*
  945      Decompresses the source buffer into the destination buffer.  sourceLen is
  946    the byte length of the source buffer. Upon entry, destLen is the total
  947    size of the destination buffer, which must be large enough to hold the
  948    entire uncompressed data. (The size of the uncompressed data must have
  949    been saved previously by the compressor and transmitted to the decompressor
  950    by some mechanism outside the scope of this compression library.)
  951    Upon exit, destLen is the actual size of the compressed buffer.
  952      This function can be used to decompress a whole file at once if the
  953    input file is mmap'ed.
  954 
  955      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
  956    enough memory, Z_BUF_ERROR if there was not enough room in the output
  957    buffer, or Z_DATA_ERROR if the input data was corrupted.
  958 */
  959 
  960 
  961 typedef voidp gzFile;
  962 
  963 ZEXTERN gzFile ZEXPORT gzopen  __P((const char *, const char *));
  964 /*
  965      Opens a gzip (.gz) file for reading or writing. The mode parameter
  966    is as in fopen ("rb" or "wb") but can also include a compression level
  967    ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
  968    Huffman only compression as in "wb1h". (See the description
  969    of deflateInit2 for more information about the strategy parameter.)
  970 
  971      gzopen can be used to read a file which is not in gzip format; in this
  972    case gzread will directly read from the file without decompression.
  973 
  974      gzopen returns NULL if the file could not be opened or if there was
  975    insufficient memory to allocate the (de)compression state; errno
  976    can be checked to distinguish the two cases (if errno is zero, the
  977    zlib error is Z_MEM_ERROR).  */
  978 
  979 ZEXTERN gzFile ZEXPORT gzdopen  __P((int, const char *));
  980 /*
  981      gzdopen() associates a gzFile with the file descriptor fd.  File
  982    descriptors are obtained from calls like open, dup, creat, pipe or
  983    fileno (in the file has been previously opened with fopen).
  984    The mode parameter is as in gzopen.
  985      The next call of gzclose on the returned gzFile will also close the
  986    file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
  987    descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
  988      gzdopen returns NULL if there was insufficient memory to allocate
  989    the (de)compression state.
  990 */
  991 
  992 ZEXTERN int ZEXPORT gzsetparams __P((gzFile, int, int));
  993 /*
  994      Dynamically update the compression level or strategy. See the description
  995    of deflateInit2 for the meaning of these parameters.
  996      gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
  997    opened for writing.
  998 */
  999 
 1000 ZEXTERN int ZEXPORT    gzread  __P((gzFile, voidp, unsigned));
 1001 /*
 1002      Reads the given number of uncompressed bytes from the compressed file.
 1003    If the input file was not in gzip format, gzread copies the given number
 1004    of bytes into the buffer.
 1005      gzread returns the number of uncompressed bytes actually read (0 for
 1006    end of file, -1 for error). */
 1007 
 1008 ZEXTERN int ZEXPORT    gzwrite __P((gzFile, const voidp, unsigned));
 1009 /*
 1010      Writes the given number of uncompressed bytes into the compressed file.
 1011    gzwrite returns the number of uncompressed bytes actually written
 1012    (0 in case of error).
 1013 */
 1014 
 1015 ZEXTERN int ZEXPORTVA   gzprintf __P((gzFile, const char *, ...))
 1016                 __attribute__((__format__(__printf__, 2, 3)));
 1017 /*
 1018      Converts, formats, and writes the args to the compressed file under
 1019    control of the format string, as in fprintf. gzprintf returns the number of
 1020    uncompressed bytes actually written (0 in case of error).
 1021 */
 1022 
 1023 ZEXTERN int ZEXPORT gzputs __P((gzFile, const char *));
 1024 /*
 1025       Writes the given null-terminated string to the compressed file, excluding
 1026    the terminating null character.
 1027       gzputs returns the number of characters written, or -1 in case of error.
 1028 */
 1029 
 1030 ZEXTERN char * ZEXPORT gzgets __P((gzFile, char *, int));
 1031 /*
 1032       Reads bytes from the compressed file until len-1 characters are read, or
 1033    a newline character is read and transferred to buf, or an end-of-file
 1034    condition is encountered.  The string is then terminated with a null
 1035    character.
 1036       gzgets returns buf, or Z_NULL in case of error.
 1037 */
 1038 
 1039 ZEXTERN int ZEXPORT    gzputc __P((gzFile, int));
 1040 /*
 1041       Writes c, converted to an unsigned char, into the compressed file.
 1042    gzputc returns the value that was written, or -1 in case of error.
 1043 */
 1044 
 1045 ZEXTERN int ZEXPORT    gzgetc __P((gzFile));
 1046 /*
 1047       Reads one byte from the compressed file. gzgetc returns this byte
 1048    or -1 in case of end of file or error.
 1049 */
 1050 
 1051 ZEXTERN int ZEXPORT    gzflush __P((gzFile, int));
 1052 /*
 1053      Flushes all pending output into the compressed file. The parameter
 1054    flush is as in the deflate() function. The return value is the zlib
 1055    error number (see function gzerror below). gzflush returns Z_OK if
 1056    the flush parameter is Z_FINISH and all output could be flushed.
 1057      gzflush should be called only when strictly necessary because it can
 1058    degrade compression.
 1059 
 1060 */
 1061 
 1062 /*
 1063  * NetBSD note:
 1064  * "long" gzseek has been there till Oct 1999 (1.4L), which was wrong.
 1065  */
 1066 ZEXTERN z_off_t ZEXPORT    gzseek __P((gzFile, z_off_t, int));
 1067 /*
 1068       Sets the starting position for the next gzread or gzwrite on the
 1069    given compressed file. The offset represents a number of bytes in the
 1070    uncompressed data stream. The whence parameter is defined as in lseek(2);
 1071    the value SEEK_END is not supported.
 1072      If the file is opened for reading, this function is emulated but can be
 1073    extremely slow. If the file is opened for writing, only forward seeks are
 1074    supported; gzseek then compresses a sequence of zeroes up to the new
 1075    starting position.
 1076 
 1077       gzseek returns the resulting offset location as measured in bytes from
 1078    the beginning of the uncompressed stream, or -1 in case of error, in
 1079    particular if the file is opened for writing and the new starting position
 1080    would be before the current position.
 1081 */
 1082 
 1083 ZEXTERN int ZEXPORT    gzrewind __P((gzFile));
 1084 /*
 1085      Rewinds the given file. This function is supported only for reading.
 1086 
 1087    gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
 1088 */
 1089 
 1090 /*
 1091  * NetBSD note:
 1092  * "long" gztell has been there till Oct 1999 (1.4L), which was wrong.
 1093  */
 1094 ZEXTERN z_off_t ZEXPORT    gztell __P((gzFile));
 1095 /*
 1096      Returns the starting position for the next gzread or gzwrite on the
 1097    given compressed file. This position represents a number of bytes in the
 1098    uncompressed data stream.
 1099 
 1100    gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
 1101 */
 1102 
 1103 ZEXTERN int ZEXPORT gzeof __P((gzFile));
 1104 /*
 1105      Returns 1 when EOF has previously been detected reading the given
 1106    input stream, otherwise zero.
 1107 */
 1108 
 1109 ZEXTERN int ZEXPORT    gzclose __P((gzFile));
 1110 /*
 1111      Flushes all pending output if necessary, closes the compressed file
 1112    and deallocates all the (de)compression state. The return value is the zlib
 1113    error number (see function gzerror below).
 1114 */
 1115 
 1116 ZEXTERN const char * ZEXPORT gzerror __P((gzFile, int *));
 1117 /*
 1118      Returns the error message for the last error which occurred on the
 1119    given compressed file. errnum is set to zlib error number. If an
 1120    error occurred in the file system and not in the compression library,
 1121    errnum is set to Z_ERRNO and the application may consult errno
 1122    to get the exact error code.
 1123 */
 1124 
 1125                         /* checksum functions */
 1126 
 1127 /*
 1128      These functions are not related to compression but are exported
 1129    anyway because they might be useful in applications using the
 1130    compression library.
 1131 */
 1132 
 1133 ZEXTERN uLong ZEXPORT adler32 __P((uLong, const Bytef *, uInt));
 1134 
 1135 /*
 1136      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
 1137    return the updated checksum. If buf is NULL, this function returns
 1138    the required initial value for the checksum.
 1139    An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
 1140    much faster. Usage example:
 1141 
 1142      uLong adler = adler32(0L, Z_NULL, 0);
 1143 
 1144      while (read_buffer(buffer, length) != EOF) {
 1145        adler = adler32(adler, buffer, length);
 1146      }
 1147      if (adler != original_adler) error();
 1148 */
 1149 
 1150 ZEXTERN uLong ZEXPORT crc32   __P((uLong, const Bytef *, uInt));
 1151 /*
 1152      Update a running crc with the bytes buf[0..len-1] and return the updated
 1153    crc. If buf is NULL, this function returns the required initial value
 1154    for the crc. Pre- and post-conditioning (one's complement) is performed
 1155    within this function so it shouldn't be done by the application.
 1156    Usage example:
 1157 
 1158      uLong crc = crc32(0L, Z_NULL, 0);
 1159 
 1160      while (read_buffer(buffer, length) != EOF) {
 1161        crc = crc32(crc, buffer, length);
 1162      }
 1163      if (crc != original_crc) error();
 1164 */
 1165 
 1166 
 1167                         /* various hacks, don't look :) */
 1168 
 1169 /* deflateInit and inflateInit are macros to allow checking the zlib version
 1170  * and the compiler's view of z_stream:
 1171  */
 1172 ZEXTERN int ZEXPORT deflateInit_ __P((z_streamp, int, const char *, int));
 1173 ZEXTERN int ZEXPORT inflateInit_ __P((z_streamp, const char *, int));
 1174 ZEXTERN int ZEXPORT deflateInit2_ __P((z_streamp, int, int, int, int,
 1175                                       int, const char *, int));
 1176 ZEXTERN int ZEXPORT inflateInit2_ __P((z_streamp, int, const char *, int));
 1177 #define deflateInit(strm, level) \
 1178         deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
 1179 #define inflateInit(strm) \
 1180         inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
 1181 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
 1182         deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
 1183                       (strategy),           ZLIB_VERSION, sizeof(z_stream))
 1184 #define inflateInit2(strm, windowBits) \
 1185         inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
 1186 
 1187 
 1188 #if !defined(Z_UTIL_H) && !defined(NO_DUMMY_DECL)
 1189     struct internal_state {int dummy;}; /* hack for buggy compilers */
 1190 #endif
 1191 
 1192 ZEXTERN const char   * ZEXPORT zError           __P((int));
 1193 ZEXTERN int            ZEXPORT inflateSyncPoint __P((z_streamp));
 1194 ZEXTERN const uLongf * ZEXPORT get_crc_table    __P((void));
 1195 
 1196 #ifdef __cplusplus
 1197 }
 1198 #endif
 1199 #endif /* !ZLIB_H */
 1200 
 1201 #endif /* !_NET_ZLIB_H_ */
 1202 /* -- zlib.h */

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