1/*
2 * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23/*	$Id: zlib.h,v 1.3 2003/08/14 00:00:39 callie Exp $	*/
24
25/*
26 * This file is derived from zlib.h and zconf.h from the zlib-0.95
27 * distribution by Jean-loup Gailly and Mark Adler, with some additions
28 * by Paul Mackerras to aid in implementing Deflate compression and
29 * decompression for PPP packets.
30 */
31
32/* zlib.h -- interface of the 'zlib' general purpose compression library
33  version 0.95, Aug 16th, 1995.
34
35  Copyright (C) 1995 Jean-loup Gailly and Mark Adler
36
37  This software is provided 'as-is', without any express or implied
38  warranty.  In no event will the authors be held liable for any damages
39  arising from the use of this software.
40
41  Permission is granted to anyone to use this software for any purpose,
42  including commercial applications, and to alter it and redistribute it
43  freely, subject to the following restrictions:
44
45  1. The origin of this software must not be misrepresented; you must not
46     claim that you wrote the original software. If you use this software
47     in a product, an acknowledgment in the product documentation would be
48     appreciated but is not required.
49  2. Altered source versions must be plainly marked as such, and must not be
50     misrepresented as being the original software.
51  3. This notice may not be removed or altered from any source distribution.
52
53  Jean-loup Gailly        Mark Adler
54  gzip@prep.ai.mit.edu    madler@alumni.caltech.edu
55 */
56
57#ifndef _ZLIB_H
58#define _ZLIB_H
59
60/* #include "zconf.h" */	/* included directly here */
61
62/* zconf.h -- configuration of the zlib compression library
63 * Copyright (C) 1995 Jean-loup Gailly.
64 * For conditions of distribution and use, see copyright notice in zlib.h
65 */
66
67/* From: zconf.h,v 1.12 1995/05/03 17:27:12 jloup Exp */
68
69/*
70     The library does not install any signal handler. It is recommended to
71  add at least a handler for SIGSEGV when decompressing; the library checks
72  the consistency of the input data whenever possible but may go nuts
73  for some forms of corrupted input.
74 */
75
76/*
77 * Compile with -DMAXSEG_64K if the alloc function cannot allocate more
78 * than 64k bytes at a time (needed on systems with 16-bit int).
79 * Compile with -DUNALIGNED_OK if it is OK to access shorts or ints
80 * at addresses which are not a multiple of their size.
81 * Under DOS, -DFAR=far or -DFAR=__far may be needed.
82 */
83
84#ifndef STDC
85#  if defined(MSDOS) || defined(__STDC__) || defined(__cplusplus)
86#    define STDC
87#  endif
88#endif
89
90#ifdef	__MWERKS__ /* Metrowerks CodeWarrior declares fileno() in unix.h */
91#  include <unix.h>
92#endif
93
94/* Maximum value for memLevel in deflateInit2 */
95#ifndef MAX_MEM_LEVEL
96#  ifdef MAXSEG_64K
97#    define MAX_MEM_LEVEL 8
98#  else
99#    define MAX_MEM_LEVEL 9
100#  endif
101#endif
102
103#ifndef FAR
104#  define FAR
105#endif
106
107/* Maximum value for windowBits in deflateInit2 and inflateInit2 */
108#ifndef MAX_WBITS
109#  define MAX_WBITS   15 /* 32K LZ77 window */
110#endif
111
112/* The memory requirements for deflate are (in bytes):
113            1 << (windowBits+2)   +  1 << (memLevel+9)
114 that is: 128K for windowBits=15  +  128K for memLevel = 8  (default values)
115 plus a few kilobytes for small objects. For example, if you want to reduce
116 the default memory requirements from 256K to 128K, compile with
117     make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
118 Of course this will generally degrade compression (there's no free lunch).
119
120   The memory requirements for inflate are (in bytes) 1 << windowBits
121 that is, 32K for windowBits=15 (default value) plus a few kilobytes
122 for small objects.
123*/
124
125                        /* Type declarations */
126
127#ifndef OF /* function prototypes */
128#  ifdef STDC
129#    define OF(args)  args
130#  else
131#    define OF(args)  ()
132#  endif
133#endif
134
135typedef unsigned char  Byte;  /* 8 bits */
136typedef unsigned int   uInt;  /* 16 bits or more */
137typedef unsigned long  uLong; /* 32 bits or more */
138
139typedef Byte FAR Bytef;
140typedef char FAR charf;
141typedef int FAR intf;
142typedef uInt FAR uIntf;
143typedef uLong FAR uLongf;
144
145#ifdef STDC
146   typedef void FAR *voidpf;
147   typedef void     *voidp;
148#else
149   typedef Byte FAR *voidpf;
150   typedef Byte     *voidp;
151#endif
152
153/* end of original zconf.h */
154
155#define ZLIB_VERSION "0.95P"
156
157/*
158     The 'zlib' compression library provides in-memory compression and
159  decompression functions, including integrity checks of the uncompressed
160  data.  This version of the library supports only one compression method
161  (deflation) but other algorithms may be added later and will have the same
162  stream interface.
163
164     For compression the application must provide the output buffer and
165  may optionally provide the input buffer for optimization. For decompression,
166  the application must provide the input buffer and may optionally provide
167  the output buffer for optimization.
168
169     Compression can be done in a single step if the buffers are large
170  enough (for example if an input file is mmap'ed), or can be done by
171  repeated calls of the compression function.  In the latter case, the
172  application must provide more input and/or consume the output
173  (providing more output space) before each call.
174*/
175
176typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
177typedef void   (*free_func)  OF((voidpf opaque, voidpf address, uInt nbytes));
178
179struct internal_state;
180
181typedef struct z_stream_s {
182    Bytef    *next_in;  /* next input byte */
183    uInt     avail_in;  /* number of bytes available at next_in */
184    uLong    total_in;  /* total nb of input bytes read so far */
185
186    Bytef    *next_out; /* next output byte should be put there */
187    uInt     avail_out; /* remaining free space at next_out */
188    uLong    total_out; /* total nb of bytes output so far */
189
190    char     *msg;      /* last error message, NULL if no error */
191    struct internal_state FAR *state; /* not visible by applications */
192
193    alloc_func zalloc;  /* used to allocate the internal state */
194    free_func  zfree;   /* used to free the internal state */
195    voidp      opaque;  /* private data object passed to zalloc and zfree */
196
197    Byte     data_type; /* best guess about the data type: ascii or binary */
198
199} z_stream;
200
201/*
202   The application must update next_in and avail_in when avail_in has
203   dropped to zero. It must update next_out and avail_out when avail_out
204   has dropped to zero. The application must initialize zalloc, zfree and
205   opaque before calling the init function. All other fields are set by the
206   compression library and must not be updated by the application.
207
208   The opaque value provided by the application will be passed as the first
209   parameter for calls of zalloc and zfree. This can be useful for custom
210   memory management. The compression library attaches no meaning to the
211   opaque value.
212
213   zalloc must return Z_NULL if there is not enough memory for the object.
214   On 16-bit systems, the functions zalloc and zfree must be able to allocate
215   exactly 65536 bytes, but will not be required to allocate more than this
216   if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
217   pointers returned by zalloc for objects of exactly 65536 bytes *must*
218   have their offset normalized to zero. The default allocation function
219   provided by this library ensures this (see zutil.c). To reduce memory
220   requirements and avoid any allocation of 64K objects, at the expense of
221   compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
222
223   The fields total_in and total_out can be used for statistics or
224   progress reports. After compression, total_in holds the total size of
225   the uncompressed data and may be saved for use in the decompressor
226   (particularly if the decompressor wants to decompress everything in
227   a single step).
228*/
229
230                        /* constants */
231
232#define Z_NO_FLUSH      0
233#define Z_PARTIAL_FLUSH 1
234#define Z_FULL_FLUSH    2
235#define Z_SYNC_FLUSH    3 /* experimental: partial_flush + byte align */
236#define Z_FINISH        4
237#define Z_PACKET_FLUSH	5
238/* See deflate() below for the usage of these constants */
239
240#define Z_OK            0
241#define Z_STREAM_END    1
242#define Z_ERRNO        (-1)
243#define Z_STREAM_ERROR (-2)
244#define Z_DATA_ERROR   (-3)
245#define Z_MEM_ERROR    (-4)
246#define Z_BUF_ERROR    (-5)
247/* error codes for the compression/decompression functions */
248
249#define Z_BEST_SPEED             1
250#define Z_BEST_COMPRESSION       9
251#define Z_DEFAULT_COMPRESSION  (-1)
252/* compression levels */
253
254#define Z_FILTERED            1
255#define Z_HUFFMAN_ONLY        2
256#define Z_DEFAULT_STRATEGY    0
257
258#define Z_BINARY   0
259#define Z_ASCII    1
260#define Z_UNKNOWN  2
261/* Used to set the data_type field */
262
263#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
264
265extern char *zlib_version;
266/* The application can compare zlib_version and ZLIB_VERSION for consistency.
267   If the first character differs, the library code actually used is
268   not compatible with the zlib.h header file used by the application.
269 */
270
271                        /* basic functions */
272
273extern int deflateInit OF((z_stream *strm, int level));
274/*
275     Initializes the internal stream state for compression. The fields
276   zalloc, zfree and opaque must be initialized before by the caller.
277   If zalloc and zfree are set to Z_NULL, deflateInit updates them to
278   use default allocation functions.
279
280     The compression level must be Z_DEFAULT_COMPRESSION, or between 1 and 9:
281   1 gives best speed, 9 gives best compression. Z_DEFAULT_COMPRESSION requests
282   a default compromise between speed and compression (currently equivalent
283   to level 6).
284
285     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
286   enough memory, Z_STREAM_ERROR if level is not a valid compression level.
287   msg is set to null if there is no error message.  deflateInit does not
288   perform any compression: this will be done by deflate().
289*/
290
291
292extern int deflate OF((z_stream *strm, int flush));
293/*
294  Performs one or both of the following actions:
295
296  - Compress more input starting at next_in and update next_in and avail_in
297    accordingly. If not all input can be processed (because there is not
298    enough room in the output buffer), next_in and avail_in are updated and
299    processing will resume at this point for the next call of deflate().
300
301  - Provide more output starting at next_out and update next_out and avail_out
302    accordingly. This action is forced if the parameter flush is non zero.
303    Forcing flush frequently degrades the compression ratio, so this parameter
304    should be set only when necessary (in interactive applications).
305    Some output may be provided even if flush is not set.
306
307  Before the call of deflate(), the application should ensure that at least
308  one of the actions is possible, by providing more input and/or consuming
309  more output, and updating avail_in or avail_out accordingly; avail_out
310  should never be zero before the call. The application can consume the
311  compressed output when it wants, for example when the output buffer is full
312  (avail_out == 0), or after each call of deflate().
313
314    If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression
315  block is terminated and flushed to the output buffer so that the
316  decompressor can get all input data available so far. For method 9, a future
317  variant on method 8, the current block will be flushed but not terminated.
318  If flush is set to Z_FULL_FLUSH, the compression block is terminated, a
319  special marker is output and the compression dictionary is discarded; this
320  is useful to allow the decompressor to synchronize if one compressed block
321  has been damaged (see inflateSync below).  Flushing degrades compression and
322  so should be used only when necessary.  Using Z_FULL_FLUSH too often can
323  seriously degrade the compression. If deflate returns with avail_out == 0,
324  this function must be called again with the same value of the flush
325  parameter and more output space (updated avail_out), until the flush is
326  complete (deflate returns with non-zero avail_out).
327
328    If the parameter flush is set to Z_PACKET_FLUSH, the compression
329  block is terminated, and a zero-length stored block is output,
330  omitting the length bytes (the effect of this is that the 3-bit type
331  code 000 for a stored block is output, and the output is then
332  byte-aligned).  This is designed for use at the end of a PPP packet.
333  In addition, if the current compression block contains all the data
334  since the last Z_PACKET_FLUSH, it is never output as a stored block.
335  If the current compression block output as a static or dynamic block
336  would not be at least `minCompression' bytes smaller than the
337  original data, then nothing is output for that block.  (The type
338  code for the zero-length stored block is still output, resulting in
339  a single zero byte being output for the whole packet.)
340  `MinCompression' is a parameter to deflateInit2, or 0 if deflateInit
341  is used.
342
343    If the parameter flush is set to Z_FINISH, all pending input is processed,
344  all pending output is flushed and deflate returns with Z_STREAM_END if there
345  was enough output space; if deflate returns with Z_OK, this function must be
346  called again with Z_FINISH and more output space (updated avail_out) but no
347  more input data, until it returns with Z_STREAM_END or an error. After
348  deflate has returned Z_STREAM_END, the only possible operations on the
349  stream are deflateReset or deflateEnd.
350
351    Z_FINISH can be used immediately after deflateInit if all the compression
352  is to be done in a single step. In this case, avail_out must be at least
353  0.1% larger than avail_in plus 12 bytes.  If deflate does not return
354  Z_STREAM_END, then it must be called again as described above.
355
356    deflate() may update data_type if it can make a good guess about
357  the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
358  binary. This field is only for information purposes and does not affect
359  the compression algorithm in any manner.
360
361    deflate() returns Z_OK if some progress has been made (more input
362  processed or more output produced), Z_STREAM_END if all input has been
363  consumed and all output has been produced (only when flush is set to
364  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
365  if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible.
366*/
367
368
369extern int deflateEnd OF((z_stream *strm));
370/*
371     All dynamically allocated data structures for this stream are freed.
372   This function discards any unprocessed input and does not flush any
373   pending output.
374
375     deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
376   stream state was inconsistent. In the error case, msg may be set
377   but then points to a static string (which must not be deallocated).
378*/
379
380
381extern int inflateInit OF((z_stream *strm));
382/*
383     Initializes the internal stream state for decompression. The fields
384   zalloc and zfree must be initialized before by the caller.  If zalloc and
385   zfree are set to Z_NULL, inflateInit updates them to use default allocation
386   functions.
387
388     inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
389   enough memory.  msg is set to null if there is no error message.
390   inflateInit does not perform any decompression: this will be done by
391   inflate().
392*/
393
394
395extern int inflate OF((z_stream *strm, int flush));
396/*
397  Performs one or both of the following actions:
398
399  - Decompress more input starting at next_in and update next_in and avail_in
400    accordingly. If not all input can be processed (because there is not
401    enough room in the output buffer), next_in is updated and processing
402    will resume at this point for the next call of inflate().
403
404  - Provide more output starting at next_out and update next_out and avail_out
405    accordingly.  inflate() always provides as much output as possible
406    (until there is no more input data or no more space in the output buffer).
407
408  Before the call of inflate(), the application should ensure that at least
409  one of the actions is possible, by providing more input and/or consuming
410  more output, and updating the next_* and avail_* values accordingly.
411  The application can consume the uncompressed output when it wants, for
412  example when the output buffer is full (avail_out == 0), or after each
413  call of inflate().
414
415    If the parameter flush is set to Z_PARTIAL_FLUSH or Z_PACKET_FLUSH,
416  inflate flushes as much output as possible to the output buffer. The
417  flushing behavior of inflate is not specified for values of the flush
418  parameter other than Z_PARTIAL_FLUSH, Z_PACKET_FLUSH or Z_FINISH, but the
419  current implementation actually flushes as much output as possible
420  anyway.  For Z_PACKET_FLUSH, inflate checks that once all the input data
421  has been consumed, it is expecting to see the length field of a stored
422  block; if not, it returns Z_DATA_ERROR.
423
424    inflate() should normally be called until it returns Z_STREAM_END or an
425  error. However if all decompression is to be performed in a single step
426  (a single call of inflate), the parameter flush should be set to
427  Z_FINISH. In this case all pending input is processed and all pending
428  output is flushed; avail_out must be large enough to hold all the
429  uncompressed data. (The size of the uncompressed data may have been saved
430  by the compressor for this purpose.) The next operation on this stream must
431  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
432  is never required, but can be used to inform inflate that a faster routine
433  may be used for the single inflate() call.
434
435    inflate() returns Z_OK if some progress has been made (more input
436  processed or more output produced), Z_STREAM_END if the end of the
437  compressed data has been reached and all uncompressed output has been
438  produced, Z_DATA_ERROR if the input data was corrupted, Z_STREAM_ERROR if
439  the stream structure was inconsistent (for example if next_in or next_out
440  was NULL), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if no
441  progress is possible or if there was not enough room in the output buffer
442  when Z_FINISH is used. In the Z_DATA_ERROR case, the application may then
443  call inflateSync to look for a good compression block.  */
444
445
446extern int inflateEnd OF((z_stream *strm));
447/*
448     All dynamically allocated data structures for this stream are freed.
449   This function discards any unprocessed input and does not flush any
450   pending output.
451
452     inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
453   was inconsistent. In the error case, msg may be set but then points to a
454   static string (which must not be deallocated).
455*/
456
457                        /* advanced functions */
458
459/*
460    The following functions are needed only in some special applications.
461*/
462
463extern int deflateInit2 OF((z_stream *strm,
464                            int  level,
465                            int  method,
466                            int  windowBits,
467                            int  memLevel,
468                            int  strategy,
469			    int  minCompression));
470/*
471     This is another version of deflateInit with more compression options. The
472   fields next_in, zalloc and zfree must be initialized before by the caller.
473
474     The method parameter is the compression method. It must be 8 in this
475   version of the library. (Method 9 will allow a 64K history buffer and
476   partial block flushes.)
477
478     The windowBits parameter is the base two logarithm of the window size
479   (the size of the history buffer).  It should be in the range 8..15 for this
480   version of the library (the value 16 will be allowed for method 9). Larger
481   values of this parameter result in better compression at the expense of
482   memory usage. The default value is 15 if deflateInit is used instead.
483
484    The memLevel parameter specifies how much memory should be allocated
485   for the internal compression state. memLevel=1 uses minimum memory but
486   is slow and reduces compression ratio; memLevel=9 uses maximum memory
487   for optimal speed. The default value is 8. See zconf.h for total memory
488   usage as a function of windowBits and memLevel.
489
490     The strategy parameter is used to tune the compression algorithm. Use
491   the value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data
492   produced by a filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman
493   encoding only (no string match).  Filtered data consists mostly of small
494   values with a somewhat random distribution. In this case, the
495   compression algorithm is tuned to compress them better. The strategy
496   parameter only affects the compression ratio but not the correctness of
497   the compressed output even if it is not set appropriately.
498
499     The minCompression parameter specifies the minimum reduction in size
500   required for a compressed block to be output when Z_PACKET_FLUSH is
501   used (see the description of deflate above).
502
503     If next_in is not null, the library will use this buffer to hold also
504   some history information; the buffer must either hold the entire input
505   data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in
506   is null, the library will allocate its own history buffer (and leave next_in
507   null). next_out need not be provided here but must be provided by the
508   application for the next call of deflate().
509
510     If the history buffer is provided by the application, next_in must
511   must never be changed by the application since the compressor maintains
512   information inside this buffer from call to call; the application
513   must provide more input only by increasing avail_in. next_in is always
514   reset by the library in this case.
515
516      deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
517   not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
518   an invalid method). msg is set to null if there is no error message.
519   deflateInit2 does not perform any compression: this will be done by
520   deflate().
521*/
522
523extern int deflateCopy OF((z_stream *dest,
524                           z_stream *source));
525/*
526     Sets the destination stream as a complete copy of the source stream.  If
527   the source stream is using an application-supplied history buffer, a new
528   buffer is allocated for the destination stream.  The compressed output
529   buffer is always application-supplied. It's the responsibility of the
530   application to provide the correct values of next_out and avail_out for the
531   next call of deflate.
532
533     This function is useful when several compression strategies will be
534   tried, for example when there are several ways of pre-processing the input
535   data with a filter. The streams that will be discarded should then be freed
536   by calling deflateEnd.  Note that deflateCopy duplicates the internal
537   compression state which can be quite large, so this strategy is slow and
538   can consume lots of memory.
539
540      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
541   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
542   (such as zalloc being NULL). msg is left unchanged in both source and
543   destination.
544*/
545
546extern int deflateReset OF((z_stream *strm));
547/*
548     This function is equivalent to deflateEnd followed by deflateInit,
549   but does not free and reallocate all the internal compression state.
550   The stream will keep the same compression level and any other attributes
551   that may have been set by deflateInit2.
552
553      deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
554   stream state was inconsistent (such as zalloc or state being NULL).
555*/
556
557extern int inflateInit2 OF((z_stream *strm,
558                            int  windowBits));
559/*
560     This is another version of inflateInit with more compression options. The
561   fields next_out, zalloc and zfree must be initialized before by the caller.
562
563     The windowBits parameter is the base two logarithm of the maximum window
564   size (the size of the history buffer).  It should be in the range 8..15 for
565   this version of the library (the value 16 will be allowed soon). The
566   default value is 15 if inflateInit is used instead. If a compressed stream
567   with a larger window size is given as input, inflate() will return with
568   the error code Z_DATA_ERROR instead of trying to allocate a larger window.
569
570     If next_out is not null, the library will use this buffer for the history
571   buffer; the buffer must either be large enough to hold the entire output
572   data, or have at least 1<<windowBits bytes.  If next_out is null, the
573   library will allocate its own buffer (and leave next_out null). next_in
574   need not be provided here but must be provided by the application for the
575   next call of inflate().
576
577     If the history buffer is provided by the application, next_out must
578   never be changed by the application since the decompressor maintains
579   history information inside this buffer from call to call; the application
580   can only reset next_out to the beginning of the history buffer when
581   avail_out is zero and all output has been consumed.
582
583      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
584   not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
585   windowBits < 8). msg is set to null if there is no error message.
586   inflateInit2 does not perform any decompression: this will be done by
587   inflate().
588*/
589
590extern int inflateSync OF((z_stream *strm));
591/*
592    Skips invalid compressed data until the special marker (see deflate()
593  above) can be found, or until all available input is skipped. No output
594  is provided.
595
596    inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR
597  if no more input was provided, Z_DATA_ERROR if no marker has been found,
598  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
599  case, the application may save the current current value of total_in which
600  indicates where valid compressed data was found. In the error case, the
601  application may repeatedly call inflateSync, providing more input each time,
602  until success or end of the input data.
603*/
604
605extern int inflateReset OF((z_stream *strm));
606/*
607     This function is equivalent to inflateEnd followed by inflateInit,
608   but does not free and reallocate all the internal decompression state.
609   The stream will keep attributes that may have been set by inflateInit2.
610
611      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
612   stream state was inconsistent (such as zalloc or state being NULL).
613*/
614
615extern int inflateIncomp OF((z_stream *strm));
616/*
617     This function adds the data at next_in (avail_in bytes) to the output
618   history without performing any output.  There must be no pending output,
619   and the decompressor must be expecting to see the start of a block.
620   Calling this function is equivalent to decompressing a stored block
621   containing the data at next_in (except that the data is not output).
622*/
623
624                        /* checksum functions */
625
626/*
627     This function is not related to compression but is exported
628   anyway because it might be useful in applications using the
629   compression library.
630*/
631
632extern uLong adler32 OF((uLong adler, Bytef *buf, uInt len));
633
634/*
635     Update a running Adler-32 checksum with the bytes buf[0..len-1] and
636   return the updated checksum. If buf is NULL, this function returns
637   the required initial value for the checksum.
638   An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
639   much faster. Usage example:
640
641     uLong adler = adler32(0L, Z_NULL, 0);
642
643     while (read_buffer(buffer, length) != EOF) {
644       adler = adler32(adler, buffer, length);
645     }
646     if (adler != original_adler) error();
647*/
648
649#ifndef _Z_UTIL_H
650    struct internal_state {int dummy;}; /* hack for buggy compilers */
651#endif
652
653#endif /* _ZLIB_H */
654