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1 62 marcus.erl
/* zlib.h -- interface of the 'zlib' general purpose compression library
2
 
3
  Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
4
 
5
  This software is provided 'as-is', without any express or implied
6
  warranty.  In no event will the authors be held liable for any damages
7
  arising from the use of this software.
8
 
9
  Permission is granted to anyone to use this software for any purpose,
10
  including commercial applications, and to alter it and redistribute it
11
  freely, subject to the following restrictions:
12
 
13
  1. The origin of this software must not be misrepresented; you must not
14
     claim that you wrote the original software. If you use this software
15
     in a product, an acknowledgment in the product documentation would be
16
     appreciated but is not required.
17
  2. Altered source versions must be plainly marked as such, and must not be
18
     misrepresented as being the original software.
19
  3. This notice may not be removed or altered from any source distribution.
20
 
21
  Jean-loup Gailly        Mark Adler
22
  jloup@gzip.org          madler@alumni.caltech.edu
23
 
24
 
25
  The data format used by the zlib library is described by RFCs (Request for
26
  Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
27
  (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
28
*/
29
 
30
#ifndef _ZLIB_H
31
#define _ZLIB_H
32
 
33
#include <linux/zconf.h>
34
 
35
/* zlib deflate based on ZLIB_VERSION "1.1.3" */
36
/* zlib inflate based on ZLIB_VERSION "1.2.3" */
37
 
38
/*
39
  This is a modified version of zlib for use inside the Linux kernel.
40
  The main changes are to perform all memory allocation in advance.
41
 
42
  Inflation Changes:
43
    * Z_PACKET_FLUSH is added and used by ppp_deflate. Before returning
44
      this checks there is no more input data available and the next data
45
      is a STORED block. It also resets the mode to be read for the next
46
      data, all as per PPP requirements.
47
    * Addition of zlib_inflateIncomp which copies incompressible data into
48
      the history window and adjusts the accoutning without calling
49
      zlib_inflate itself to inflate the data.
50
*/
51
 
52
/*
53
     The 'zlib' compression library provides in-memory compression and
54
  decompression functions, including integrity checks of the uncompressed
55
  data.  This version of the library supports only one compression method
56
  (deflation) but other algorithms will be added later and will have the same
57
  stream interface.
58
 
59
     Compression can be done in a single step if the buffers are large
60
  enough (for example if an input file is mmap'ed), or can be done by
61
  repeated calls of the compression function.  In the latter case, the
62
  application must provide more input and/or consume the output
63
  (providing more output space) before each call.
64
 
65
     The compressed data format used by default by the in-memory functions is
66
  the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
67
  around a deflate stream, which is itself documented in RFC 1951.
68
 
69
     The library also supports reading and writing files in gzip (.gz) format
70
  with an interface similar to that of stdio.
71
 
72
     The zlib format was designed to be compact and fast for use in memory
73
  and on communications channels.  The gzip format was designed for single-
74
  file compression on file systems, has a larger header than zlib to maintain
75
  directory information, and uses a different, slower check method than zlib.
76
 
77
     The library does not install any signal handler. The decoder checks
78
  the consistency of the compressed data, so the library should never
79
  crash even in case of corrupted input.
80
*/
81
 
82
struct internal_state;
83
 
84
typedef struct z_stream_s {
85
    const Byte *next_in;   /* next input byte */
86
    uInt     avail_in;  /* number of bytes available at next_in */
87
    uLong    total_in;  /* total nb of input bytes read so far */
88
 
89
    Byte    *next_out;  /* next output byte should be put there */
90
    uInt     avail_out; /* remaining free space at next_out */
91
    uLong    total_out; /* total nb of bytes output so far */
92
 
93
    char     *msg;      /* last error message, NULL if no error */
94
    struct internal_state *state; /* not visible by applications */
95
 
96
    void     *workspace; /* memory allocated for this stream */
97
 
98
    int     data_type;  /* best guess about the data type: ascii or binary */
99
    uLong   adler;      /* adler32 value of the uncompressed data */
100
    uLong   reserved;   /* reserved for future use */
101
} z_stream;
102
 
103
typedef z_stream *z_streamp;
104
 
105
/*
106
   The application must update next_in and avail_in when avail_in has
107
   dropped to zero. It must update next_out and avail_out when avail_out
108
   has dropped to zero. The application must initialize zalloc, zfree and
109
   opaque before calling the init function. All other fields are set by the
110
   compression library and must not be updated by the application.
111
 
112
   The opaque value provided by the application will be passed as the first
113
   parameter for calls of zalloc and zfree. This can be useful for custom
114
   memory management. The compression library attaches no meaning to the
115
   opaque value.
116
 
117
   zalloc must return NULL if there is not enough memory for the object.
118
   If zlib is used in a multi-threaded application, zalloc and zfree must be
119
   thread safe.
120
 
121
   On 16-bit systems, the functions zalloc and zfree must be able to allocate
122
   exactly 65536 bytes, but will not be required to allocate more than this
123
   if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
124
   pointers returned by zalloc for objects of exactly 65536 bytes *must*
125
   have their offset normalized to zero. The default allocation function
126
   provided by this library ensures this (see zutil.c). To reduce memory
127
   requirements and avoid any allocation of 64K objects, at the expense of
128
   compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
129
 
130
   The fields total_in and total_out can be used for statistics or
131
   progress reports. After compression, total_in holds the total size of
132
   the uncompressed data and may be saved for use in the decompressor
133
   (particularly if the decompressor wants to decompress everything in
134
   a single step).
135
*/
136
 
137
                        /* constants */
138
 
139
#define Z_NO_FLUSH      0
140
#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
141
#define Z_PACKET_FLUSH  2
142
#define Z_SYNC_FLUSH    3
143
#define Z_FULL_FLUSH    4
144
#define Z_FINISH        5
145
#define Z_BLOCK         6 /* Only for inflate at present */
146
/* Allowed flush values; see deflate() and inflate() below for details */
147
 
148
#define Z_OK            0
149
#define Z_STREAM_END    1
150
#define Z_NEED_DICT     2
151
#define Z_ERRNO        (-1)
152
#define Z_STREAM_ERROR (-2)
153
#define Z_DATA_ERROR   (-3)
154
#define Z_MEM_ERROR    (-4)
155
#define Z_BUF_ERROR    (-5)
156
#define Z_VERSION_ERROR (-6)
157
/* Return codes for the compression/decompression functions. Negative
158
 * values are errors, positive values are used for special but normal events.
159
 */
160
 
161
#define Z_NO_COMPRESSION         0
162
#define Z_BEST_SPEED             1
163
#define Z_BEST_COMPRESSION       9
164
#define Z_DEFAULT_COMPRESSION  (-1)
165
/* compression levels */
166
 
167
#define Z_FILTERED            1
168
#define Z_HUFFMAN_ONLY        2
169
#define Z_DEFAULT_STRATEGY    0
170
/* compression strategy; see deflateInit2() below for details */
171
 
172
#define Z_BINARY   0
173
#define Z_ASCII    1
174
#define Z_UNKNOWN  2
175
/* Possible values of the data_type field */
176
 
177
#define Z_DEFLATED   8
178
/* The deflate compression method (the only one supported in this version) */
179
 
180
                        /* basic functions */
181
 
182
extern int zlib_deflate_workspacesize (void);
183
/*
184
   Returns the number of bytes that needs to be allocated for a per-
185
   stream workspace.  A pointer to this number of bytes should be
186
   returned in stream->workspace before calling zlib_deflateInit().
187
*/
188
 
189
/*
190
extern int deflateInit (z_streamp strm, int level);
191
 
192
     Initializes the internal stream state for compression. The fields
193
   zalloc, zfree and opaque must be initialized before by the caller.
194
   If zalloc and zfree are set to NULL, deflateInit updates them to
195
   use default allocation functions.
196
 
197
     The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
198
   1 gives best speed, 9 gives best compression, 0 gives no compression at
199
   all (the input data is simply copied a block at a time).
200
   Z_DEFAULT_COMPRESSION requests a default compromise between speed and
201
   compression (currently equivalent to level 6).
202
 
203
     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
204
   enough memory, Z_STREAM_ERROR if level is not a valid compression level,
205
   Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
206
   with the version assumed by the caller (ZLIB_VERSION).
207
   msg is set to null if there is no error message.  deflateInit does not
208
   perform any compression: this will be done by deflate().
209
*/
210
 
211
 
212
extern int zlib_deflate (z_streamp strm, int flush);
213
/*
214
    deflate compresses as much data as possible, and stops when the input
215
  buffer becomes empty or the output buffer becomes full. It may introduce some
216
  output latency (reading input without producing any output) except when
217
  forced to flush.
218
 
219
    The detailed semantics are as follows. deflate performs one or both of the
220
  following actions:
221
 
222
  - Compress more input starting at next_in and update next_in and avail_in
223
    accordingly. If not all input can be processed (because there is not
224
    enough room in the output buffer), next_in and avail_in are updated and
225
    processing will resume at this point for the next call of deflate().
226
 
227
  - Provide more output starting at next_out and update next_out and avail_out
228
    accordingly. This action is forced if the parameter flush is non zero.
229
    Forcing flush frequently degrades the compression ratio, so this parameter
230
    should be set only when necessary (in interactive applications).
231
    Some output may be provided even if flush is not set.
232
 
233
  Before the call of deflate(), the application should ensure that at least
234
  one of the actions is possible, by providing more input and/or consuming
235
  more output, and updating avail_in or avail_out accordingly; avail_out
236
  should never be zero before the call. The application can consume the
237
  compressed output when it wants, for example when the output buffer is full
238
  (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
239
  and with zero avail_out, it must be called again after making room in the
240
  output buffer because there might be more output pending.
241
 
242
    If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
243
  flushed to the output buffer and the output is aligned on a byte boundary, so
244
  that the decompressor can get all input data available so far. (In particular
245
  avail_in is zero after the call if enough output space has been provided
246
  before the call.)  Flushing may degrade compression for some compression
247
  algorithms and so it should be used only when necessary.
248
 
249
    If flush is set to Z_FULL_FLUSH, all output is flushed as with
250
  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
251
  restart from this point if previous compressed data has been damaged or if
252
  random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
253
  the compression.
254
 
255
    If deflate returns with avail_out == 0, this function must be called again
256
  with the same value of the flush parameter and more output space (updated
257
  avail_out), until the flush is complete (deflate returns with non-zero
258
  avail_out).
259
 
260
    If the parameter flush is set to Z_FINISH, pending input is processed,
261
  pending output is flushed and deflate returns with Z_STREAM_END if there
262
  was enough output space; if deflate returns with Z_OK, this function must be
263
  called again with Z_FINISH and more output space (updated avail_out) but no
264
  more input data, until it returns with Z_STREAM_END or an error. After
265
  deflate has returned Z_STREAM_END, the only possible operations on the
266
  stream are deflateReset or deflateEnd.
267
 
268
    Z_FINISH can be used immediately after deflateInit if all the compression
269
  is to be done in a single step. In this case, avail_out must be at least
270
  0.1% larger than avail_in plus 12 bytes.  If deflate does not return
271
  Z_STREAM_END, then it must be called again as described above.
272
 
273
    deflate() sets strm->adler to the adler32 checksum of all input read
274
  so far (that is, total_in bytes).
275
 
276
    deflate() may update data_type if it can make a good guess about
277
  the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
278
  binary. This field is only for information purposes and does not affect
279
  the compression algorithm in any manner.
280
 
281
    deflate() returns Z_OK if some progress has been made (more input
282
  processed or more output produced), Z_STREAM_END if all input has been
283
  consumed and all output has been produced (only when flush is set to
284
  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
285
  if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
286
  (for example avail_in or avail_out was zero).
287
*/
288
 
289
 
290
extern int zlib_deflateEnd (z_streamp strm);
291
/*
292
     All dynamically allocated data structures for this stream are freed.
293
   This function discards any unprocessed input and does not flush any
294
   pending output.
295
 
296
     deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
297
   stream state was inconsistent, Z_DATA_ERROR if the stream was freed
298
   prematurely (some input or output was discarded). In the error case,
299
   msg may be set but then points to a static string (which must not be
300
   deallocated).
301
*/
302
 
303
 
304
extern int zlib_inflate_workspacesize (void);
305
/*
306
   Returns the number of bytes that needs to be allocated for a per-
307
   stream workspace.  A pointer to this number of bytes should be
308
   returned in stream->workspace before calling zlib_inflateInit().
309
*/
310
 
311
/*
312
extern int zlib_inflateInit (z_streamp strm);
313
 
314
     Initializes the internal stream state for decompression. The fields
315
   next_in, avail_in, and workspace must be initialized before by
316
   the caller. If next_in is not NULL and avail_in is large enough (the exact
317
   value depends on the compression method), inflateInit determines the
318
   compression method from the zlib header and allocates all data structures
319
   accordingly; otherwise the allocation will be deferred to the first call of
320
   inflate.  If zalloc and zfree are set to NULL, inflateInit updates them to
321
   use default allocation functions.
322
 
323
     inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
324
   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
325
   version assumed by the caller.  msg is set to null if there is no error
326
   message. inflateInit does not perform any decompression apart from reading
327
   the zlib header if present: this will be done by inflate().  (So next_in and
328
   avail_in may be modified, but next_out and avail_out are unchanged.)
329
*/
330
 
331
 
332
extern int zlib_inflate (z_streamp strm, int flush);
333
/*
334
    inflate decompresses as much data as possible, and stops when the input
335
  buffer becomes empty or the output buffer becomes full. It may introduce
336
  some output latency (reading input without producing any output) except when
337
  forced to flush.
338
 
339
  The detailed semantics are as follows. inflate performs one or both of the
340
  following actions:
341
 
342
  - Decompress more input starting at next_in and update next_in and avail_in
343
    accordingly. If not all input can be processed (because there is not
344
    enough room in the output buffer), next_in is updated and processing
345
    will resume at this point for the next call of inflate().
346
 
347
  - Provide more output starting at next_out and update next_out and avail_out
348
    accordingly.  inflate() provides as much output as possible, until there
349
    is no more input data or no more space in the output buffer (see below
350
    about the flush parameter).
351
 
352
  Before the call of inflate(), the application should ensure that at least
353
  one of the actions is possible, by providing more input and/or consuming
354
  more output, and updating the next_* and avail_* values accordingly.
355
  The application can consume the uncompressed output when it wants, for
356
  example when the output buffer is full (avail_out == 0), or after each
357
  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
358
  must be called again after making room in the output buffer because there
359
  might be more output pending.
360
 
361
    The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
362
  Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
363
  output as possible to the output buffer. Z_BLOCK requests that inflate() stop
364
  if and when it gets to the next deflate block boundary. When decoding the
365
  zlib or gzip format, this will cause inflate() to return immediately after
366
  the header and before the first block. When doing a raw inflate, inflate()
367
  will go ahead and process the first block, and will return when it gets to
368
  the end of that block, or when it runs out of data.
369
 
370
    The Z_BLOCK option assists in appending to or combining deflate streams.
371
  Also to assist in this, on return inflate() will set strm->data_type to the
372
  number of unused bits in the last byte taken from strm->next_in, plus 64
373
  if inflate() is currently decoding the last block in the deflate stream,
374
  plus 128 if inflate() returned immediately after decoding an end-of-block
375
  code or decoding the complete header up to just before the first byte of the
376
  deflate stream. The end-of-block will not be indicated until all of the
377
  uncompressed data from that block has been written to strm->next_out.  The
378
  number of unused bits may in general be greater than seven, except when
379
  bit 7 of data_type is set, in which case the number of unused bits will be
380
  less than eight.
381
 
382
    inflate() should normally be called until it returns Z_STREAM_END or an
383
  error. However if all decompression is to be performed in a single step
384
  (a single call of inflate), the parameter flush should be set to
385
  Z_FINISH. In this case all pending input is processed and all pending
386
  output is flushed; avail_out must be large enough to hold all the
387
  uncompressed data. (The size of the uncompressed data may have been saved
388
  by the compressor for this purpose.) The next operation on this stream must
389
  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
390
  is never required, but can be used to inform inflate that a faster approach
391
  may be used for the single inflate() call.
392
 
393
     In this implementation, inflate() always flushes as much output as
394
  possible to the output buffer, and always uses the faster approach on the
395
  first call. So the only effect of the flush parameter in this implementation
396
  is on the return value of inflate(), as noted below, or when it returns early
397
  because Z_BLOCK is used.
398
 
399
     If a preset dictionary is needed after this call (see inflateSetDictionary
400
  below), inflate sets strm->adler to the adler32 checksum of the dictionary
401
  chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
402
  strm->adler to the adler32 checksum of all output produced so far (that is,
403
  total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
404
  below. At the end of the stream, inflate() checks that its computed adler32
405
  checksum is equal to that saved by the compressor and returns Z_STREAM_END
406
  only if the checksum is correct.
407
 
408
    inflate() will decompress and check either zlib-wrapped or gzip-wrapped
409
  deflate data.  The header type is detected automatically.  Any information
410
  contained in the gzip header is not retained, so applications that need that
411
  information should instead use raw inflate, see inflateInit2() below, or
412
  inflateBack() and perform their own processing of the gzip header and
413
  trailer.
414
 
415
    inflate() returns Z_OK if some progress has been made (more input processed
416
  or more output produced), Z_STREAM_END if the end of the compressed data has
417
  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
418
  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
419
  corrupted (input stream not conforming to the zlib format or incorrect check
420
  value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
421
  if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
422
  Z_BUF_ERROR if no progress is possible or if there was not enough room in the
423
  output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
424
  inflate() can be called again with more input and more output space to
425
  continue decompressing. If Z_DATA_ERROR is returned, the application may then
426
  call inflateSync() to look for a good compression block if a partial recovery
427
  of the data is desired.
428
*/
429
 
430
 
431
extern int zlib_inflateEnd (z_streamp strm);
432
/*
433
     All dynamically allocated data structures for this stream are freed.
434
   This function discards any unprocessed input and does not flush any
435
   pending output.
436
 
437
     inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
438
   was inconsistent. In the error case, msg may be set but then points to a
439
   static string (which must not be deallocated).
440
*/
441
 
442
                        /* Advanced functions */
443
 
444
/*
445
    The following functions are needed only in some special applications.
446
*/
447
 
448
/*
449
extern int deflateInit2 (z_streamp strm,
450
                                     int  level,
451
                                     int  method,
452
                                     int  windowBits,
453
                                     int  memLevel,
454
                                     int  strategy);
455
 
456
     This is another version of deflateInit with more compression options. The
457
   fields next_in, zalloc, zfree and opaque must be initialized before by
458
   the caller.
459
 
460
     The method parameter is the compression method. It must be Z_DEFLATED in
461
   this version of the library.
462
 
463
     The windowBits parameter is the base two logarithm of the window size
464
   (the size of the history buffer).  It should be in the range 8..15 for this
465
   version of the library. Larger values of this parameter result in better
466
   compression at the expense of memory usage. The default value is 15 if
467
   deflateInit is used instead.
468
 
469
     The memLevel parameter specifies how much memory should be allocated
470
   for the internal compression state. memLevel=1 uses minimum memory but
471
   is slow and reduces compression ratio; memLevel=9 uses maximum memory
472
   for optimal speed. The default value is 8. See zconf.h for total memory
473
   usage as a function of windowBits and memLevel.
474
 
475
     The strategy parameter is used to tune the compression algorithm. Use the
476
   value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
477
   filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
478
   string match).  Filtered data consists mostly of small values with a
479
   somewhat random distribution. In this case, the compression algorithm is
480
   tuned to compress them better. The effect of Z_FILTERED is to force more
481
   Huffman coding and less string matching; it is somewhat intermediate
482
   between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
483
   the compression ratio but not the correctness of the compressed output even
484
   if it is not set appropriately.
485
 
486
      deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
487
   memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
488
   method). msg is set to null if there is no error message.  deflateInit2 does
489
   not perform any compression: this will be done by deflate().
490
*/
491
 
492
#if 0
493
extern int zlib_deflateSetDictionary (z_streamp strm,
494
                                                     const Byte *dictionary,
495
                                                     uInt  dictLength);
496
#endif
497
/*
498
     Initializes the compression dictionary from the given byte sequence
499
   without producing any compressed output. This function must be called
500
   immediately after deflateInit, deflateInit2 or deflateReset, before any
501
   call of deflate. The compressor and decompressor must use exactly the same
502
   dictionary (see inflateSetDictionary).
503
 
504
     The dictionary should consist of strings (byte sequences) that are likely
505
   to be encountered later in the data to be compressed, with the most commonly
506
   used strings preferably put towards the end of the dictionary. Using a
507
   dictionary is most useful when the data to be compressed is short and can be
508
   predicted with good accuracy; the data can then be compressed better than
509
   with the default empty dictionary.
510
 
511
     Depending on the size of the compression data structures selected by
512
   deflateInit or deflateInit2, a part of the dictionary may in effect be
513
   discarded, for example if the dictionary is larger than the window size in
514
   deflate or deflate2. Thus the strings most likely to be useful should be
515
   put at the end of the dictionary, not at the front.
516
 
517
     Upon return of this function, strm->adler is set to the Adler32 value
518
   of the dictionary; the decompressor may later use this value to determine
519
   which dictionary has been used by the compressor. (The Adler32 value
520
   applies to the whole dictionary even if only a subset of the dictionary is
521
   actually used by the compressor.)
522
 
523
     deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
524
   parameter is invalid (such as NULL dictionary) or the stream state is
525
   inconsistent (for example if deflate has already been called for this stream
526
   or if the compression method is bsort). deflateSetDictionary does not
527
   perform any compression: this will be done by deflate().
528
*/
529
 
530
#if 0
531
extern int zlib_deflateCopy (z_streamp dest, z_streamp source);
532
#endif
533
 
534
/*
535
     Sets the destination stream as a complete copy of the source stream.
536
 
537
     This function can be useful when several compression strategies will be
538
   tried, for example when there are several ways of pre-processing the input
539
   data with a filter. The streams that will be discarded should then be freed
540
   by calling deflateEnd.  Note that deflateCopy duplicates the internal
541
   compression state which can be quite large, so this strategy is slow and
542
   can consume lots of memory.
543
 
544
     deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
545
   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
546
   (such as zalloc being NULL). msg is left unchanged in both source and
547
   destination.
548
*/
549
 
550
extern int zlib_deflateReset (z_streamp strm);
551
/*
552
     This function is equivalent to deflateEnd followed by deflateInit,
553
   but does not free and reallocate all the internal compression state.
554
   The stream will keep the same compression level and any other attributes
555
   that may have been set by deflateInit2.
556
 
557
      deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
558
   stream state was inconsistent (such as zalloc or state being NULL).
559
*/
560
 
561
static inline unsigned long deflateBound(unsigned long s)
562
{
563
        return s + ((s + 7) >> 3) + ((s + 63) >> 6) + 11;
564
}
565
 
566
#if 0
567
extern int zlib_deflateParams (z_streamp strm, int level, int strategy);
568
#endif
569
/*
570
     Dynamically update the compression level and compression strategy.  The
571
   interpretation of level and strategy is as in deflateInit2.  This can be
572
   used to switch between compression and straight copy of the input data, or
573
   to switch to a different kind of input data requiring a different
574
   strategy. If the compression level is changed, the input available so far
575
   is compressed with the old level (and may be flushed); the new level will
576
   take effect only at the next call of deflate().
577
 
578
     Before the call of deflateParams, the stream state must be set as for
579
   a call of deflate(), since the currently available input may have to
580
   be compressed and flushed. In particular, strm->avail_out must be non-zero.
581
 
582
     deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
583
   stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
584
   if strm->avail_out was zero.
585
*/
586
 
587
/*
588
extern int inflateInit2 (z_streamp strm, int  windowBits);
589
 
590
     This is another version of inflateInit with an extra parameter. The
591
   fields next_in, avail_in, zalloc, zfree and opaque must be initialized
592
   before by the caller.
593
 
594
     The windowBits parameter is the base two logarithm of the maximum window
595
   size (the size of the history buffer).  It should be in the range 8..15 for
596
   this version of the library. The default value is 15 if inflateInit is used
597
   instead. windowBits must be greater than or equal to the windowBits value
598
   provided to deflateInit2() while compressing, or it must be equal to 15 if
599
   deflateInit2() was not used. If a compressed stream with a larger window
600
   size is given as input, inflate() will return with the error code
601
   Z_DATA_ERROR instead of trying to allocate a larger window.
602
 
603
     windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
604
   determines the window size. inflate() will then process raw deflate data,
605
   not looking for a zlib or gzip header, not generating a check value, and not
606
   looking for any check values for comparison at the end of the stream. This
607
   is for use with other formats that use the deflate compressed data format
608
   such as zip.  Those formats provide their own check values. If a custom
609
   format is developed using the raw deflate format for compressed data, it is
610
   recommended that a check value such as an adler32 or a crc32 be applied to
611
   the uncompressed data as is done in the zlib, gzip, and zip formats.  For
612
   most applications, the zlib format should be used as is. Note that comments
613
   above on the use in deflateInit2() applies to the magnitude of windowBits.
614
 
615
     windowBits can also be greater than 15 for optional gzip decoding. Add
616
   32 to windowBits to enable zlib and gzip decoding with automatic header
617
   detection, or add 16 to decode only the gzip format (the zlib format will
618
   return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is
619
   a crc32 instead of an adler32.
620
 
621
     inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
622
   memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
623
   is set to null if there is no error message.  inflateInit2 does not perform
624
   any decompression apart from reading the zlib header if present: this will
625
   be done by inflate(). (So next_in and avail_in may be modified, but next_out
626
   and avail_out are unchanged.)
627
*/
628
 
629
extern int zlib_inflateSetDictionary (z_streamp strm,
630
                                                     const Byte *dictionary,
631
                                                     uInt  dictLength);
632
/*
633
     Initializes the decompression dictionary from the given uncompressed byte
634
   sequence. This function must be called immediately after a call of inflate,
635
   if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
636
   can be determined from the adler32 value returned by that call of inflate.
637
   The compressor and decompressor must use exactly the same dictionary (see
638
   deflateSetDictionary).  For raw inflate, this function can be called
639
   immediately after inflateInit2() or inflateReset() and before any call of
640
   inflate() to set the dictionary.  The application must insure that the
641
   dictionary that was used for compression is provided.
642
 
643
     inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
644
   parameter is invalid (such as NULL dictionary) or the stream state is
645
   inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
646
   expected one (incorrect adler32 value). inflateSetDictionary does not
647
   perform any decompression: this will be done by subsequent calls of
648
   inflate().
649
*/
650
 
651
#if 0
652
extern int zlib_inflateSync (z_streamp strm);
653
#endif
654
/*
655
    Skips invalid compressed data until a full flush point (see above the
656
  description of deflate with Z_FULL_FLUSH) can be found, or until all
657
  available input is skipped. No output is provided.
658
 
659
    inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
660
  if no more input was provided, Z_DATA_ERROR if no flush point has been found,
661
  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
662
  case, the application may save the current current value of total_in which
663
  indicates where valid compressed data was found. In the error case, the
664
  application may repeatedly call inflateSync, providing more input each time,
665
  until success or end of the input data.
666
*/
667
 
668
extern int zlib_inflateReset (z_streamp strm);
669
/*
670
     This function is equivalent to inflateEnd followed by inflateInit,
671
   but does not free and reallocate all the internal decompression state.
672
   The stream will keep attributes that may have been set by inflateInit2.
673
 
674
      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
675
   stream state was inconsistent (such as zalloc or state being NULL).
676
*/
677
 
678
extern int zlib_inflateIncomp (z_stream *strm);
679
/*
680
     This function adds the data at next_in (avail_in bytes) to the output
681
   history without performing any output.  There must be no pending output,
682
   and the decompressor must be expecting to see the start of a block.
683
   Calling this function is equivalent to decompressing a stored block
684
   containing the data at next_in (except that the data is not output).
685
*/
686
 
687
#define zlib_deflateInit(strm, level) \
688
        zlib_deflateInit2((strm), (level), Z_DEFLATED, MAX_WBITS, \
689
                              DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY)
690
#define zlib_inflateInit(strm) \
691
        zlib_inflateInit2((strm), DEF_WBITS)
692
 
693
extern int zlib_deflateInit2(z_streamp strm, int  level, int  method,
694
                                      int windowBits, int memLevel,
695
                                      int strategy);
696
extern int zlib_inflateInit2(z_streamp strm, int  windowBits);
697
 
698
#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
699
    struct internal_state {int dummy;}; /* hack for buggy compilers */
700
#endif
701
 
702
/* Utility function: initialize zlib, unpack binary blob, clean up zlib,
703
 * return len or negative error code. */
704
extern int zlib_inflate_blob(void *dst, unsigned dst_sz, const void *src, unsigned src_sz);
705
 
706
#endif /* _ZLIB_H */

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