xref: /netbsd-src/sys/net/zlib.h (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /* $NetBSD: zlib.h,v 1.14 2009/03/25 01:26:12 darran 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 1.14 2009/03/25 01:26:12 darran 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)(voidpf, uInt, uInt);
357 typedef void   (*free_func)(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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(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 #ifdef STANDALONE
1151 ZEXTERN uLong ZEXPORT crc32(uLong, const Bytef *, uInt);
1152 #endif
1153 /*
1154      Update a running crc with the bytes buf[0..len-1] and return the updated
1155    crc. If buf is NULL, this function returns the required initial value
1156    for the crc. Pre- and post-conditioning (one's complement) is performed
1157    within this function so it shouldn't be done by the application.
1158    Usage example:
1159 
1160      uLong crc = crc32(0L, Z_NULL, 0);
1161 
1162      while (read_buffer(buffer, length) != EOF) {
1163        crc = crc32(crc, buffer, length);
1164      }
1165      if (crc != original_crc) error();
1166 */
1167 
1168 
1169                         /* various hacks, don't look :) */
1170 
1171 /* deflateInit and inflateInit are macros to allow checking the zlib version
1172  * and the compiler's view of z_stream:
1173  */
1174 ZEXTERN int ZEXPORT deflateInit_(z_streamp, int, const char *, int);
1175 ZEXTERN int ZEXPORT inflateInit_(z_streamp, const char *, int);
1176 ZEXTERN int ZEXPORT deflateInit2_(z_streamp, int, int, int, int,
1177                                       int, const char *, int);
1178 ZEXTERN int ZEXPORT inflateInit2_(z_streamp, int, const char *, int);
1179 #define deflateInit(strm, level) \
1180         deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
1181 #define inflateInit(strm) \
1182         inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
1183 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1184         deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1185                       (strategy),           ZLIB_VERSION, sizeof(z_stream))
1186 #define inflateInit2(strm, windowBits) \
1187         inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
1188 
1189 
1190 #if !defined(Z_UTIL_H) && !defined(NO_DUMMY_DECL)
1191     struct internal_state {int dummy;}; /* hack for buggy compilers */
1192 #endif
1193 
1194 ZEXTERN const char   * ZEXPORT zError(int);
1195 ZEXTERN int            ZEXPORT inflateSyncPoint(z_streamp);
1196 ZEXTERN const uLongf * ZEXPORT get_crc_table(void);
1197 
1198 #ifdef __cplusplus
1199 }
1200 #endif
1201 #endif /* !ZLIB_H */
1202 
1203 #endif /* !_NET_ZLIB_H_ */
1204 /* -- zlib.h */
1205