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zlib.h
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4  | |
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6  | See: http://www.mrpt.org/Authors - All rights reserved. |
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8  +------------------------------------------------------------------------+ */
9 
10 #ifndef ZLIB_H
11 #define ZLIB_H
12 
13 #include "zconf.h"
14 
15 #ifdef __cplusplus
16 extern "C" {
17 #endif
18 
19 #define ZLIB_VERSION "1.2.3"
20 #define ZLIB_VERNUM 0x1230
21 
22 /*
23  The 'zlib' compression library provides in-memory compression and
24  decompression functions, including integrity checks of the uncompressed
25  data. This version of the library supports only one compression method
26  (deflation) but other algorithms will be added later and will have the same
27  stream interface.
28 
29  Compression can be done in a single step if the buffers are large
30  enough (for example if an input file is mmap'ed), or can be done by
31  repeated calls of the compression function. In the latter case, the
32  application must provide more input and/or consume the output
33  (providing more output space) before each call.
34 
35  The compressed data format used by default by the in-memory functions is
36  the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
37  around a deflate stream, which is itself documented in RFC 1951.
38 
39  The library also supports reading and writing files in gzip (.gz) format
40  with an interface similar to that of stdio using the functions that start
41  with "gz". The gzip format is different from the zlib format. gzip is a
42  gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
43 
44  This library can optionally read and write gzip streams in memory as well.
45 
46  The zlib format was designed to be compact and fast for use in memory
47  and on communications channels. The gzip format was designed for single-
48  file compression on file systems, has a larger header than zlib to maintain
49  directory information, and uses a different, slower check method than zlib.
50 
51  The library does not install any signal handler. The decoder checks
52  the consistency of the compressed data, so the library should never
53  crash even in case of corrupted input.
54 */
55 
56 typedef voidpf(*alloc_func) OF((voidpf opaque, uInt items, uInt size));
57 typedef void(*free_func) OF((voidpf opaque, voidpf address));
58 
59 struct internal_state;
60 
61 typedef struct z_stream_s
62 {
63  Bytef* next_in; /* next input byte */
64  uInt avail_in; /* number of bytes available at next_in */
65  uLong total_in; /* total nb of input bytes read so far */
66 
67  Bytef* next_out; /* next output byte should be put there */
68  uInt avail_out; /* remaining free space at next_out */
69  uLong total_out; /* total nb of bytes output so far */
70 
71  char* msg; /* last error message, nullptr if no error */
72  struct internal_state FAR* state; /* not visible by applications */
73 
74  alloc_func zalloc; /* used to allocate the internal state */
75  free_func zfree; /* used to free the internal state */
76  voidpf opaque; /* private data object passed to zalloc and zfree */
77 
78  int data_type; /* best guess about the data type: binary or text */
79  uLong adler; /* adler32 value of the uncompressed data */
80  uLong reserved; /* reserved for future use */
81 } z_stream;
82 
84 
85 /*
86  gzip header information passed to and from zlib routines. See RFC 1952
87  for more details on the meanings of these fields.
88 */
89 typedef struct gz_header_s
90 {
91  int text; /* true if compressed data believed to be text */
92  uLong time; /* modification time */
93  int xflags; /* extra flags (not used when writing a gzip file) */
94  int os; /* operating system */
95  Bytef* extra; /* pointer to extra field or Z_NULL if none */
96  uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
97  uInt extra_max; /* space at extra (only when reading header) */
98  Bytef* name; /* pointer to zero-terminated file name or Z_NULL */
99  uInt name_max; /* space at name (only when reading header) */
100  Bytef* comment; /* pointer to zero-terminated comment or Z_NULL */
101  uInt comm_max; /* space at comment (only when reading header) */
102  int hcrc; /* true if there was or will be a header crc */
103  int done; /* true when done reading gzip header (not used
104  when writing a gzip file) */
105 } gz_header;
106 
108 
109 /*
110  The application must update next_in and avail_in when avail_in has
111  dropped to zero. It must update next_out and avail_out when avail_out
112  has dropped to zero. The application must initialize zalloc, zfree and
113  opaque before calling the init function. All other fields are set by the
114  compression library and must not be updated by the application.
115 
116  The opaque value provided by the application will be passed as the first
117  parameter for calls of zalloc and zfree. This can be useful for custom
118  memory management. The compression library attaches no meaning to the
119  opaque value.
120 
121  zalloc must return Z_NULL if there is not enough memory for the object.
122  If zlib is used in a multi-threaded application, zalloc and zfree must be
123  thread safe.
124 
125  On 16-bit systems, the functions zalloc and zfree must be able to allocate
126  exactly 65536 bytes, but will not be required to allocate more than this
127  if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
128  pointers returned by zalloc for objects of exactly 65536 bytes *must*
129  have their offset normalized to zero. The default allocation function
130  provided by this library ensures this (see zutil.c). To reduce memory
131  requirements and avoid any allocation of 64K objects, at the expense of
132  compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
133 
134  The fields total_in and total_out can be used for statistics or
135  progress reports. After compression, total_in holds the total size of
136  the uncompressed data and may be saved for use in the decompressor
137  (particularly if the decompressor wants to decompress everything in
138  a single step).
139 */
140 
141 /* constants */
142 
143 #define Z_NO_FLUSH 0
144 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
145 #define Z_SYNC_FLUSH 2
146 #define Z_FULL_FLUSH 3
147 #define Z_FINISH 4
148 #define Z_BLOCK 5
149 /* Allowed flush values; see deflate() and inflate() below for details */
150 
151 #define Z_OK 0
152 #define Z_STREAM_END 1
153 #define Z_NEED_DICT 2
154 #define Z_ERRNO (-1)
155 #define Z_STREAM_ERROR (-2)
156 #define Z_DATA_ERROR (-3)
157 #define Z_MEM_ERROR (-4)
158 #define Z_BUF_ERROR (-5)
159 #define Z_VERSION_ERROR (-6)
160 /* Return codes for the compression/decompression functions. Negative
161  * values are errors, positive values are used for special but normal events.
162  */
163 
164 #define Z_NO_COMPRESSION 0
165 #define Z_BEST_SPEED 1
166 #define Z_BEST_COMPRESSION 9
167 #define Z_DEFAULT_COMPRESSION (-1)
168 /* compression levels */
169 
170 #define Z_FILTERED 1
171 #define Z_HUFFMAN_ONLY 2
172 #define Z_RLE 3
173 #define Z_FIXED 4
174 #define Z_DEFAULT_STRATEGY 0
175 /* compression strategy; see deflateInit2() below for details */
176 
177 #define Z_BINARY 0
178 #define Z_TEXT 1
179 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
180 #define Z_UNKNOWN 2
181 /* Possible values of the data_type field (though see inflate()) */
182 
183 #define Z_DEFLATED 8
184 /* The deflate compression method (the only one supported in this version) */
185 
186 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
187 
188 #define zlib_version zlibVersion()
189 /* for compatibility with versions < 1.0.2 */
190 
191 /* basic functions */
192 
193 ZEXTERN const char* ZEXPORT zlibVersion OF((void));
194 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
195  If the first character differs, the library code actually used is
196  not compatible with the zlib.h header file used by the application.
197  This check is automatically made by deflateInit and inflateInit.
198  */
199 
200 /*
201 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
202 
203  Initializes the internal stream state for compression. The fields
204  zalloc, zfree and opaque must be initialized before by the caller.
205  If zalloc and zfree are set to Z_NULL, deflateInit updates them to
206  use default allocation functions.
207 
208  The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
209  1 gives best speed, 9 gives best compression, 0 gives no compression at
210  all (the input data is simply copied a block at a time).
211  Z_DEFAULT_COMPRESSION requests a default compromise between speed and
212  compression (currently equivalent to level 6).
213 
214  deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
215  enough memory, Z_STREAM_ERROR if level is not a valid compression level,
216  Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
217  with the version assumed by the caller (ZLIB_VERSION).
218  msg is set to null if there is no error message. deflateInit does not
219  perform any compression: this will be done by deflate().
220 */
221 
222 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
223 /*
224  deflate compresses as much data as possible, and stops when the input
225  buffer becomes empty or the output buffer becomes full. It may introduce some
226  output latency (reading input without producing any output) except when
227  forced to flush.
228 
229  The detailed semantics are as follows. deflate performs one or both of the
230  following actions:
231 
232  - Compress more input starting at next_in and update next_in and avail_in
233  accordingly. If not all input can be processed (because there is not
234  enough room in the output buffer), next_in and avail_in are updated and
235  processing will resume at this point for the next call of deflate().
236 
237  - Provide more output starting at next_out and update next_out and avail_out
238  accordingly. This action is forced if the parameter flush is non zero.
239  Forcing flush frequently degrades the compression ratio, so this parameter
240  should be set only when necessary (in interactive applications).
241  Some output may be provided even if flush is not set.
242 
243  Before the call of deflate(), the application should ensure that at least
244  one of the actions is possible, by providing more input and/or consuming
245  more output, and updating avail_in or avail_out accordingly; avail_out
246  should never be zero before the call. The application can consume the
247  compressed output when it wants, for example when the output buffer is full
248  (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
249  and with zero avail_out, it must be called again after making room in the
250  output buffer because there might be more output pending.
251 
252  Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
253  decide how much data to accumualte before producing output, in order to
254  maximize compression.
255 
256  If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
257  flushed to the output buffer and the output is aligned on a byte boundary, so
258  that the decompressor can get all input data available so far. (In particular
259  avail_in is zero after the call if enough output space has been provided
260  before the call.) Flushing may degrade compression for some compression
261  algorithms and so it should be used only when necessary.
262 
263  If flush is set to Z_FULL_FLUSH, all output is flushed as with
264  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
265  restart from this point if previous compressed data has been damaged or if
266  random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
267  compression.
268 
269  If deflate returns with avail_out == 0, this function must be called again
270  with the same value of the flush parameter and more output space (updated
271  avail_out), until the flush is complete (deflate returns with non-zero
272  avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
273  avail_out is greater than six to avoid repeated flush markers due to
274  avail_out == 0 on return.
275 
276  If the parameter flush is set to Z_FINISH, pending input is processed,
277  pending output is flushed and deflate returns with Z_STREAM_END if there
278  was enough output space; if deflate returns with Z_OK, this function must be
279  called again with Z_FINISH and more output space (updated avail_out) but no
280  more input data, until it returns with Z_STREAM_END or an error. After
281  deflate has returned Z_STREAM_END, the only possible operations on the
282  stream are deflateReset or deflateEnd.
283 
284  Z_FINISH can be used immediately after deflateInit if all the compression
285  is to be done in a single step. In this case, avail_out must be at least
286  the value returned by deflateBound (see below). If deflate does not return
287  Z_STREAM_END, then it must be called again as described above.
288 
289  deflate() sets strm->adler to the adler32 checksum of all input read
290  so far (that is, total_in bytes).
291 
292  deflate() may update strm->data_type if it can make a good guess about
293  the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
294  binary. This field is only for information purposes and does not affect
295  the compression algorithm in any manner.
296 
297  deflate() returns Z_OK if some progress has been made (more input
298  processed or more output produced), Z_STREAM_END if all input has been
299  consumed and all output has been produced (only when flush is set to
300  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
301  if next_in or next_out was nullptr), Z_BUF_ERROR if no progress is possible
302  (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
303  fatal, and deflate() can be called again with more input and more output
304  space to continue compressing.
305 */
306 
307 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
308 /*
309  All dynamically allocated data structures for this stream are freed.
310  This function discards any unprocessed input and does not flush any
311  pending output.
312 
313  deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
314  stream state was inconsistent, Z_DATA_ERROR if the stream was freed
315  prematurely (some input or output was discarded). In the error case,
316  msg may be set but then points to a static string (which must not be
317  deallocated).
318 */
319 
320 /*
321 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
322 
323  Initializes the internal stream state for decompression. The fields
324  next_in, avail_in, zalloc, zfree and opaque must be initialized before by
325  the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
326  value depends on the compression method), inflateInit determines the
327  compression method from the zlib header and allocates all data structures
328  accordingly; otherwise the allocation will be deferred to the first call of
329  inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
330  use default allocation functions.
331 
332  inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
333  memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
334  version assumed by the caller. msg is set to null if there is no error
335  message. inflateInit does not perform any decompression apart from reading
336  the zlib header if present: this will be done by inflate(). (So next_in and
337  avail_in may be modified, but next_out and avail_out are unchanged.)
338 */
339 
340 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
341 /*
342  inflate decompresses as much data as possible, and stops when the input
343  buffer becomes empty or the output buffer becomes full. It may introduce
344  some output latency (reading input without producing any output) except when
345  forced to flush.
346 
347  The detailed semantics are as follows. inflate performs one or both of the
348  following actions:
349 
350  - Decompress more input starting at next_in and update next_in and avail_in
351  accordingly. If not all input can be processed (because there is not
352  enough room in the output buffer), next_in is updated and processing
353  will resume at this point for the next call of inflate().
354 
355  - Provide more output starting at next_out and update next_out and avail_out
356  accordingly. inflate() provides as much output as possible, until there
357  is no more input data or no more space in the output buffer (see below
358  about the flush parameter).
359 
360  Before the call of inflate(), the application should ensure that at least
361  one of the actions is possible, by providing more input and/or consuming
362  more output, and updating the next_* and avail_* values accordingly.
363  The application can consume the uncompressed output when it wants, for
364  example when the output buffer is full (avail_out == 0), or after each
365  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
366  must be called again after making room in the output buffer because there
367  might be more output pending.
368 
369  The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
370  Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
371  output as possible to the output buffer. Z_BLOCK requests that inflate() stop
372  if and when it gets to the next deflate block boundary. When decoding the
373  zlib or gzip format, this will cause inflate() to return immediately after
374  the header and before the first block. When doing a raw inflate, inflate()
375  will go ahead and process the first block, and will return when it gets to
376  the end of that block, or when it runs out of data.
377 
378  The Z_BLOCK option assists in appending to or combining deflate streams.
379  Also to assist in this, on return inflate() will set strm->data_type to the
380  number of unused bits in the last byte taken from strm->next_in, plus 64
381  if inflate() is currently decoding the last block in the deflate stream,
382  plus 128 if inflate() returned immediately after decoding an end-of-block
383  code or decoding the complete header up to just before the first byte of the
384  deflate stream. The end-of-block will not be indicated until all of the
385  uncompressed data from that block has been written to strm->next_out. The
386  number of unused bits may in general be greater than seven, except when
387  bit 7 of data_type is set, in which case the number of unused bits will be
388  less than eight.
389 
390  inflate() should normally be called until it returns Z_STREAM_END or an
391  error. However if all decompression is to be performed in a single step
392  (a single call of inflate), the parameter flush should be set to
393  Z_FINISH. In this case all pending input is processed and all pending
394  output is flushed; avail_out must be large enough to hold all the
395  uncompressed data. (The size of the uncompressed data may have been saved
396  by the compressor for this purpose.) The next operation on this stream must
397  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
398  is never required, but can be used to inform inflate that a faster approach
399  may be used for the single inflate() call.
400 
401  In this implementation, inflate() always flushes as much output as
402  possible to the output buffer, and always uses the faster approach on the
403  first call. So the only effect of the flush parameter in this implementation
404  is on the return value of inflate(), as noted below, or when it returns early
405  because Z_BLOCK is used.
406 
407  If a preset dictionary is needed after this call (see inflateSetDictionary
408  below), inflate sets strm->adler to the adler32 checksum of the dictionary
409  chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
410  strm->adler to the adler32 checksum of all output produced so far (that is,
411  total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
412  below. At the end of the stream, inflate() checks that its computed adler32
413  checksum is equal to that saved by the compressor and returns Z_STREAM_END
414  only if the checksum is correct.
415 
416  inflate() will decompress and check either zlib-wrapped or gzip-wrapped
417  deflate data. The header type is detected automatically. Any information
418  contained in the gzip header is not retained, so applications that need that
419  information should instead use raw inflate, see inflateInit2() below, or
420  inflateBack() and perform their own processing of the gzip header and
421  trailer.
422 
423  inflate() returns Z_OK if some progress has been made (more input processed
424  or more output produced), Z_STREAM_END if the end of the compressed data has
425  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
426  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
427  corrupted (input stream not conforming to the zlib format or incorrect check
428  value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
429  if next_in or next_out was nullptr), Z_MEM_ERROR if there was not enough
430  memory,
431  Z_BUF_ERROR if no progress is possible or if there was not enough room in the
432  output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
433  inflate() can be called again with more input and more output space to
434  continue decompressing. If Z_DATA_ERROR is returned, the application may then
435  call inflateSync() to look for a good compression block if a partial recovery
436  of the data is desired.
437 */
438 
439 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
440 /*
441  All dynamically allocated data structures for this stream are freed.
442  This function discards any unprocessed input and does not flush any
443  pending output.
444 
445  inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
446  was inconsistent. In the error case, msg may be set but then points to a
447  static string (which must not be deallocated).
448 */
449 
450 /* Advanced functions */
451 
452 /*
453  The following functions are needed only in some special applications.
454 */
455 
456 /*
457 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
458  int level,
459  int method,
460  int windowBits,
461  int memLevel,
462  int strategy));
463 
464  This is another version of deflateInit with more compression options. The
465  fields next_in, zalloc, zfree and opaque must be initialized before by
466  the caller.
467 
468  The method parameter is the compression method. It must be Z_DEFLATED in
469  this version of the library.
470 
471  The windowBits parameter is the base two logarithm of the window size
472  (the size of the history buffer). It should be in the range 8..15 for this
473  version of the library. Larger values of this parameter result in better
474  compression at the expense of memory usage. The default value is 15 if
475  deflateInit is used instead.
476 
477  windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
478  determines the window size. deflate() will then generate raw deflate data
479  with no zlib header or trailer, and will not compute an adler32 check value.
480 
481  windowBits can also be greater than 15 for optional gzip encoding. Add
482  16 to windowBits to write a simple gzip header and trailer around the
483  compressed data instead of a zlib wrapper. The gzip header will have no
484  file name, no extra data, no comment, no modification time (set to zero),
485  no header crc, and the operating system will be set to 255 (unknown). If a
486  gzip stream is being written, strm->adler is a crc32 instead of an adler32.
487 
488  The memLevel parameter specifies how much memory should be allocated
489  for the internal compression state. memLevel=1 uses minimum memory but
490  is slow and reduces compression ratio; memLevel=9 uses maximum memory
491  for optimal speed. The default value is 8. See zconf.h for total memory
492  usage as a function of windowBits and memLevel.
493 
494  The strategy parameter is used to tune the compression algorithm. Use the
495  value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
496  filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
497  string match), or Z_RLE to limit match distances to one (run-length
498  encoding). Filtered data consists mostly of small values with a somewhat
499  random distribution. In this case, the compression algorithm is tuned to
500  compress them better. The effect of Z_FILTERED is to force more Huffman
501  coding and less string matching; it is somewhat intermediate between
502  Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
503  Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
504  parameter only affects the compression ratio but not the correctness of the
505  compressed output even if it is not set appropriately. Z_FIXED prevents the
506  use of dynamic Huffman codes, allowing for a simpler decoder for special
507  applications.
508 
509  deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
510  memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
511  method). msg is set to null if there is no error message. deflateInit2 does
512  not perform any compression: this will be done by deflate().
513 */
514 
515 ZEXTERN int ZEXPORT deflateSetDictionary
516  OF((z_streamp strm, const Bytef* dictionary, uInt dictLength));
517 /*
518  Initializes the compression dictionary from the given byte sequence
519  without producing any compressed output. This function must be called
520  immediately after deflateInit, deflateInit2 or deflateReset, before any
521  call of deflate. The compressor and decompressor must use exactly the same
522  dictionary (see inflateSetDictionary).
523 
524  The dictionary should consist of strings (byte sequences) that are likely
525  to be encountered later in the data to be compressed, with the most commonly
526  used strings preferably put towards the end of the dictionary. Using a
527  dictionary is most useful when the data to be compressed is short and can be
528  predicted with good accuracy; the data can then be compressed better than
529  with the default empty dictionary.
530 
531  Depending on the size of the compression data structures selected by
532  deflateInit or deflateInit2, a part of the dictionary may in effect be
533  discarded, for example if the dictionary is larger than the window size in
534  deflate or deflate2. Thus the strings most likely to be useful should be
535  put at the end of the dictionary, not at the front. In addition, the
536  current implementation of deflate will use at most the window size minus
537  262 bytes of the provided dictionary.
538 
539  Upon return of this function, strm->adler is set to the adler32 value
540  of the dictionary; the decompressor may later use this value to determine
541  which dictionary has been used by the compressor. (The adler32 value
542  applies to the whole dictionary even if only a subset of the dictionary is
543  actually used by the compressor.) If a raw deflate was requested, then the
544  adler32 value is not computed and strm->adler is not set.
545 
546  deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
547  parameter is invalid (such as nullptr dictionary) or the stream state is
548  inconsistent (for example if deflate has already been called for this stream
549  or if the compression method is bsort). deflateSetDictionary does not
550  perform any compression: this will be done by deflate().
551 */
552 
553 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, z_streamp source));
554 /*
555  Sets the destination stream as a complete copy of the source stream.
556 
557  This function can be useful when several compression strategies will be
558  tried, for example when there are several ways of pre-processing the input
559  data with a filter. The streams that will be discarded should then be freed
560  by calling deflateEnd. Note that deflateCopy duplicates the internal
561  compression state which can be quite large, so this strategy is slow and
562  can consume lots of memory.
563 
564  deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
565  enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
566  (such as zalloc being nullptr). msg is left unchanged in both source and
567  destination.
568 */
569 
570 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
571 /*
572  This function is equivalent to deflateEnd followed by deflateInit,
573  but does not free and reallocate all the internal compression state.
574  The stream will keep the same compression level and any other attributes
575  that may have been set by deflateInit2.
576 
577  deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
578  stream state was inconsistent (such as zalloc or state being nullptr).
579 */
580 
581 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, int level, int strategy));
582 /*
583  Dynamically update the compression level and compression strategy. The
584  interpretation of level and strategy is as in deflateInit2. This can be
585  used to switch between compression and straight copy of the input data, or
586  to switch to a different kind of input data requiring a different
587  strategy. If the compression level is changed, the input available so far
588  is compressed with the old level (and may be flushed); the new level will
589  take effect only at the next call of deflate().
590 
591  Before the call of deflateParams, the stream state must be set as for
592  a call of deflate(), since the currently available input may have to
593  be compressed and flushed. In particular, strm->avail_out must be non-zero.
594 
595  deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
596  stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
597  if strm->avail_out was zero.
598 */
599 
600 ZEXTERN int ZEXPORT deflateTune
601  OF((z_streamp strm, int good_length, int max_lazy, int nice_length,
602  int max_chain));
603 /*
604  Fine tune deflate's internal compression parameters. This should only be
605  used by someone who understands the algorithm used by zlib's deflate for
606  searching for the best matching string, and even then only by the most
607  fanatic optimizer trying to squeeze out the last compressed bit for their
608  specific input data. Read the deflate.c source code for the meaning of the
609  max_lazy, good_length, nice_length, and max_chain parameters.
610 
611  deflateTune() can be called after deflateInit() or deflateInit2(), and
612  returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
613  */
614 
615 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, uLong sourceLen));
616 /*
617  deflateBound() returns an upper bound on the compressed size after
618  deflation of sourceLen bytes. It must be called after deflateInit()
619  or deflateInit2(). This would be used to allocate an output buffer
620  for deflation in a single pass, and so would be called before deflate().
621 */
622 
623 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, int bits, int value));
624 /*
625  deflatePrime() inserts bits in the deflate output stream. The intent
626  is that this function is used to start off the deflate output with the
627  bits leftover from a previous deflate stream when appending to it. As such,
628  this function can only be used for raw deflate, and must be used before the
629  first deflate() call after a deflateInit2() or deflateReset(). bits must be
630  less than or equal to 16, and that many of the least significant bits of
631  value will be inserted in the output.
632 
633  deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
634  stream state was inconsistent.
635 */
636 
637 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, gz_headerp head));
638 /*
639  deflateSetHeader() provides gzip header information for when a gzip
640  stream is requested by deflateInit2(). deflateSetHeader() may be called
641  after deflateInit2() or deflateReset() and before the first call of
642  deflate(). The text, time, os, extra field, name, and comment information
643  in the provided gz_header structure are written to the gzip header (xflag is
644  ignored -- the extra flags are set according to the compression level). The
645  caller must assure that, if not Z_NULL, name and comment are terminated with
646  a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
647  available there. If hcrc is true, a gzip header crc is included. Note that
648  the current versions of the command-line version of gzip (up through version
649  1.3.x) do not support header crc's, and will report that it is a "multi-part
650  gzip file" and give up.
651 
652  If deflateSetHeader is not used, the default gzip header has text false,
653  the time set to zero, and os set to 255, with no extra, name, or comment
654  fields. The gzip header is returned to the default state by deflateReset().
655 
656  deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
657  stream state was inconsistent.
658 */
659 
660 /*
661 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
662  int windowBits));
663 
664  This is another version of inflateInit with an extra parameter. The
665  fields next_in, avail_in, zalloc, zfree and opaque must be initialized
666  before by the caller.
667 
668  The windowBits parameter is the base two logarithm of the maximum window
669  size (the size of the history buffer). It should be in the range 8..15 for
670  this version of the library. The default value is 15 if inflateInit is used
671  instead. windowBits must be greater than or equal to the windowBits value
672  provided to deflateInit2() while compressing, or it must be equal to 15 if
673  deflateInit2() was not used. If a compressed stream with a larger window
674  size is given as input, inflate() will return with the error code
675  Z_DATA_ERROR instead of trying to allocate a larger window.
676 
677  windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
678  determines the window size. inflate() will then process raw deflate data,
679  not looking for a zlib or gzip header, not generating a check value, and not
680  looking for any check values for comparison at the end of the stream. This
681  is for use with other formats that use the deflate compressed data format
682  such as zip. Those formats provide their own check values. If a custom
683  format is developed using the raw deflate format for compressed data, it is
684  recommended that a check value such as an adler32 or a crc32 be applied to
685  the uncompressed data as is done in the zlib, gzip, and zip formats. For
686  most applications, the zlib format should be used as is. Note that comments
687  above on the use in deflateInit2() applies to the magnitude of windowBits.
688 
689  windowBits can also be greater than 15 for optional gzip decoding. Add
690  32 to windowBits to enable zlib and gzip decoding with automatic header
691  detection, or add 16 to decode only the gzip format (the zlib format will
692  return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
693  a crc32 instead of an adler32.
694 
695  inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
696  memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
697  is set to null if there is no error message. inflateInit2 does not perform
698  any decompression apart from reading the zlib header if present: this will
699  be done by inflate(). (So next_in and avail_in may be modified, but next_out
700  and avail_out are unchanged.)
701 */
702 
703 ZEXTERN int ZEXPORT inflateSetDictionary
704  OF((z_streamp strm, const Bytef* dictionary, uInt dictLength));
705 /*
706  Initializes the decompression dictionary from the given uncompressed byte
707  sequence. This function must be called immediately after a call of inflate,
708  if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
709  can be determined from the adler32 value returned by that call of inflate.
710  The compressor and decompressor must use exactly the same dictionary (see
711  deflateSetDictionary). For raw inflate, this function can be called
712  immediately after inflateInit2() or inflateReset() and before any call of
713  inflate() to set the dictionary. The application must insure that the
714  dictionary that was used for compression is provided.
715 
716  inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
717  parameter is invalid (such as nullptr dictionary) or the stream state is
718  inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
719  expected one (incorrect adler32 value). inflateSetDictionary does not
720  perform any decompression: this will be done by subsequent calls of
721  inflate().
722 */
723 
724 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
725 /*
726  Skips invalid compressed data until a full flush point (see above the
727  description of deflate with Z_FULL_FLUSH) can be found, or until all
728  available input is skipped. No output is provided.
729 
730  inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
731  if no more input was provided, Z_DATA_ERROR if no flush point has been found,
732  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
733  case, the application may save the current current value of total_in which
734  indicates where valid compressed data was found. In the error case, the
735  application may repeatedly call inflateSync, providing more input each time,
736  until success or end of the input data.
737 */
738 
739 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, z_streamp source));
740 /*
741  Sets the destination stream as a complete copy of the source stream.
742 
743  This function can be useful when randomly accessing a large stream. The
744  first pass through the stream can periodically record the inflate state,
745  allowing restarting inflate at those points when randomly accessing the
746  stream.
747 
748  inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
749  enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
750  (such as zalloc being nullptr). msg is left unchanged in both source and
751  destination.
752 */
753 
754 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
755 /*
756  This function is equivalent to inflateEnd followed by inflateInit,
757  but does not free and reallocate all the internal decompression state.
758  The stream will keep attributes that may have been set by inflateInit2.
759 
760  inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
761  stream state was inconsistent (such as zalloc or state being nullptr).
762 */
763 
764 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, int bits, int value));
765 /*
766  This function inserts bits in the inflate input stream. The intent is
767  that this function is used to start inflating at a bit position in the
768  middle of a byte. The provided bits will be used before any bytes are used
769  from next_in. This function should only be used with raw inflate, and
770  should be used before the first inflate() call after inflateInit2() or
771  inflateReset(). bits must be less than or equal to 16, and that many of the
772  least significant bits of value will be inserted in the input.
773 
774  inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
775  stream state was inconsistent.
776 */
777 
778 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, gz_headerp head));
779 /*
780  inflateGetHeader() requests that gzip header information be stored in the
781  provided gz_header structure. inflateGetHeader() may be called after
782  inflateInit2() or inflateReset(), and before the first call of inflate().
783  As inflate() processes the gzip stream, head->done is zero until the header
784  is completed, at which time head->done is set to one. If a zlib stream is
785  being decoded, then head->done is set to -1 to indicate that there will be
786  no gzip header information forthcoming. Note that Z_BLOCK can be used to
787  force inflate() to return immediately after header processing is complete
788  and before any actual data is decompressed.
789 
790  The text, time, xflags, and os fields are filled in with the gzip header
791  contents. hcrc is set to true if there is a header CRC. (The header CRC
792  was valid if done is set to one.) If extra is not Z_NULL, then extra_max
793  contains the maximum number of bytes to write to extra. Once done is true,
794  extra_len contains the actual extra field length, and extra contains the
795  extra field, or that field truncated if extra_max is less than extra_len.
796  If name is not Z_NULL, then up to name_max characters are written there,
797  terminated with a zero unless the length is greater than name_max. If
798  comment is not Z_NULL, then up to comm_max characters are written there,
799  terminated with a zero unless the length is greater than comm_max. When
800  any of extra, name, or comment are not Z_NULL and the respective field is
801  not present in the header, then that field is set to Z_NULL to signal its
802  absence. This allows the use of deflateSetHeader() with the returned
803  structure to duplicate the header. However if those fields are set to
804  allocated memory, then the application will need to save those pointers
805  elsewhere so that they can be eventually freed.
806 
807  If inflateGetHeader is not used, then the header information is simply
808  discarded. The header is always checked for validity, including the header
809  CRC if present. inflateReset() will reset the process to discard the header
810  information. The application would need to call inflateGetHeader() again to
811  retrieve the header from the next gzip stream.
812 
813  inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
814  stream state was inconsistent.
815 */
816 
817 /*
818 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
819  unsigned char FAR *window));
820 
821  Initialize the internal stream state for decompression using inflateBack()
822  calls. The fields zalloc, zfree and opaque in strm must be initialized
823  before the call. If zalloc and zfree are Z_NULL, then the default library-
824  derived memory allocation routines are used. windowBits is the base two
825  logarithm of the window size, in the range 8..15. window is a caller
826  supplied buffer of that size. Except for special applications where it is
827  assured that deflate was used with small window sizes, windowBits must be 15
828  and a 32K byte window must be supplied to be able to decompress general
829  deflate streams.
830 
831  See inflateBack() for the usage of these routines.
832 
833  inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
834  the paramaters are invalid, Z_MEM_ERROR if the internal state could not
835  be allocated, or Z_VERSION_ERROR if the version of the library does not
836  match the version of the header file.
837 */
838 
839 typedef unsigned(*in_func) OF((void FAR*, unsigned char FAR* FAR*));
840 typedef int(*out_func) OF((void FAR*, unsigned char FAR*, unsigned));
841 
842 ZEXTERN int ZEXPORT inflateBack
843  OF((z_streamp strm, in_func in, void FAR* in_desc, out_func out,
844  void FAR* out_desc));
845 /*
846  inflateBack() does a raw inflate with a single call using a call-back
847  interface for input and output. This is more efficient than inflate() for
848  file i/o applications in that it avoids copying between the output and the
849  sliding window by simply making the window itself the output buffer. This
850  function trusts the application to not change the output buffer passed by
851  the output function, at least until inflateBack() returns.
852 
853  inflateBackInit() must be called first to allocate the internal state
854  and to initialize the state with the user-provided window buffer.
855  inflateBack() may then be used multiple times to inflate a complete, raw
856  deflate stream with each call. inflateBackEnd() is then called to free
857  the allocated state.
858 
859  A raw deflate stream is one with no zlib or gzip header or trailer.
860  This routine would normally be used in a utility that reads zip or gzip
861  files and writes out uncompressed files. The utility would decode the
862  header and process the trailer on its own, hence this routine expects
863  only the raw deflate stream to decompress. This is different from the
864  normal behavior of inflate(), which expects either a zlib or gzip header and
865  trailer around the deflate stream.
866 
867  inflateBack() uses two subroutines supplied by the caller that are then
868  called by inflateBack() for input and output. inflateBack() calls those
869  routines until it reads a complete deflate stream and writes out all of the
870  uncompressed data, or until it encounters an error. The function's
871  parameters and return types are defined above in the in_func and out_func
872  typedefs. inflateBack() will call in(in_desc, &buf) which should return the
873  number of bytes of provided input, and a pointer to that input in buf. If
874  there is no input available, in() must return zero--buf is ignored in that
875  case--and inflateBack() will return a buffer error. inflateBack() will call
876  out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
877  should return zero on success, or non-zero on failure. If out() returns
878  non-zero, inflateBack() will return with an error. Neither in() nor out()
879  are permitted to change the contents of the window provided to
880  inflateBackInit(), which is also the buffer that out() uses to write from.
881  The length written by out() will be at most the window size. Any non-zero
882  amount of input may be provided by in().
883 
884  For convenience, inflateBack() can be provided input on the first call by
885  setting strm->next_in and strm->avail_in. If that input is exhausted, then
886  in() will be called. Therefore strm->next_in must be initialized before
887  calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
888  immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
889  must also be initialized, and then if strm->avail_in is not zero, input will
890  initially be taken from strm->next_in[0 .. strm->avail_in - 1].
891 
892  The in_desc and out_desc parameters of inflateBack() is passed as the
893  first parameter of in() and out() respectively when they are called. These
894  descriptors can be optionally used to pass any information that the caller-
895  supplied in() and out() functions need to do their job.
896 
897  On return, inflateBack() will set strm->next_in and strm->avail_in to
898  pass back any unused input that was provided by the last in() call. The
899  return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
900  if in() or out() returned an error, Z_DATA_ERROR if there was a format
901  error in the deflate stream (in which case strm->msg is set to indicate the
902  nature of the error), or Z_STREAM_ERROR if the stream was not properly
903  initialized. In the case of Z_BUF_ERROR, an input or output error can be
904  distinguished using strm->next_in which will be Z_NULL only if in() returned
905  an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
906  out() returning non-zero. (in() will always be called before out(), so
907  strm->next_in is assured to be defined if out() returns non-zero.) Note
908  that inflateBack() cannot return Z_OK.
909 */
910 
911 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
912 /*
913  All memory allocated by inflateBackInit() is freed.
914 
915  inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
916  state was inconsistent.
917 */
918 
919 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
920 /* Return flags indicating compile-time options.
921 
922  Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
923  1.0: size of uInt
924  3.2: size of uLong
925  5.4: size of voidpf (pointer)
926  7.6: size of z_off_t
927 
928  Compiler, assembler, and debug options:
929  8: DEBUG
930  9: ASMV or ASMINF -- use ASM code
931  10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
932  11: 0 (reserved)
933 
934  One-time table building (smaller code, but not thread-safe if true):
935  12: BUILDFIXED -- build static block decoding tables when needed
936  13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
937  14,15: 0 (reserved)
938 
939  Library content (indicates missing functionality):
940  16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
941  deflate code when not needed)
942  17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
943  and decode gzip streams (to avoid linking crc code)
944  18-19: 0 (reserved)
945 
946  Operation variations (changes in library functionality):
947  20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
948  21: FASTEST -- deflate algorithm with only one, lowest compression level
949  22,23: 0 (reserved)
950 
951  The sprintf variant used by gzprintf (zero is best):
952  24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
953  25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
954  26: 0 = returns value, 1 = void -- 1 means inferred string length returned
955 
956  Remainder:
957  27-31: 0 (reserved)
958  */
959 
960 /* utility functions */
961 
962 /*
963  The following utility functions are implemented on top of the
964  basic stream-oriented functions. To simplify the interface, some
965  default options are assumed (compression level and memory usage,
966  standard memory allocation functions). The source code of these
967  utility functions can easily be modified if you need special options.
968 */
969 
971  OF((Bytef * dest, uLongf* destLen, const Bytef* source, uLong sourceLen));
972 /*
973  Compresses the source buffer into the destination buffer. sourceLen is
974  the byte length of the source buffer. Upon entry, destLen is the total
975  size of the destination buffer, which must be at least the value returned
976  by compressBound(sourceLen). Upon exit, destLen is the actual size of the
977  compressed buffer.
978  This function can be used to compress a whole file at once if the
979  input file is mmap'ed.
980  compress returns Z_OK if success, Z_MEM_ERROR if there was not
981  enough memory, Z_BUF_ERROR if there was not enough room in the output
982  buffer.
983 */
984 
985 ZEXTERN int ZEXPORT compress2
986  OF((Bytef * dest, uLongf* destLen, const Bytef* source, uLong sourceLen,
987  int level));
988 /*
989  Compresses the source buffer into the destination buffer. The level
990  parameter has the same meaning as in deflateInit. sourceLen is the byte
991  length of the source buffer. Upon entry, destLen is the total size of the
992  destination buffer, which must be at least the value returned by
993  compressBound(sourceLen). Upon exit, destLen is the actual size of the
994  compressed buffer.
995 
996  compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
997  memory, Z_BUF_ERROR if there was not enough room in the output buffer,
998  Z_STREAM_ERROR if the level parameter is invalid.
999 */
1000 
1001 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1002 /*
1003  compressBound() returns an upper bound on the compressed size after
1004  compress() or compress2() on sourceLen bytes. It would be used before
1005  a compress() or compress2() call to allocate the destination buffer.
1006 */
1007 
1008 ZEXTERN int ZEXPORT uncompress
1009  OF((Bytef * dest, uLongf* destLen, const Bytef* source, uLong sourceLen));
1010 /*
1011  Decompresses the source buffer into the destination buffer. sourceLen is
1012  the byte length of the source buffer. Upon entry, destLen is the total
1013  size of the destination buffer, which must be large enough to hold the
1014  entire uncompressed data. (The size of the uncompressed data must have
1015  been saved previously by the compressor and transmitted to the decompressor
1016  by some mechanism outside the scope of this compression library.)
1017  Upon exit, destLen is the actual size of the compressed buffer.
1018  This function can be used to decompress a whole file at once if the
1019  input file is mmap'ed.
1020 
1021  uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1022  enough memory, Z_BUF_ERROR if there was not enough room in the output
1023  buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
1024 */
1025 
1026 typedef voidp gzFile;
1027 
1028 ZEXTERN gzFile ZEXPORT gzopen OF((const char* path, const char* mode));
1029 /*
1030  Opens a gzip (.gz) file for reading or writing. The mode parameter
1031  is as in fopen ("rb" or "wb") but can also include a compression level
1032  ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
1033  Huffman only compression as in "wb1h", or 'R' for run-length encoding
1034  as in "wb1R". (See the description of deflateInit2 for more information
1035  about the strategy parameter.)
1036 
1037  gzopen can be used to read a file which is not in gzip format; in this
1038  case gzread will directly read from the file without decompression.
1039 
1040  gzopen returns nullptr if the file could not be opened or if there was
1041  insufficient memory to allocate the (de)compression state; errno
1042  can be checked to distinguish the two cases (if errno is zero, the
1043  zlib error is Z_MEM_ERROR). */
1044 
1045 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char* mode));
1046 /*
1047  gzdopen() associates a gzFile with the file descriptor fd. File
1048  descriptors are obtained from calls like open, dup, creat, pipe or
1049  fileno (in the file has been previously opened with fopen).
1050  The mode parameter is as in gzopen.
1051  The next call of gzclose on the returned gzFile will also close the
1052  file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
1053  descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
1054  gzdopen returns nullptr if there was insufficient memory to allocate
1055  the (de)compression state.
1056 */
1057 
1058 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1059 /*
1060  Dynamically update the compression level or strategy. See the description
1061  of deflateInit2 for the meaning of these parameters.
1062  gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1063  opened for writing.
1064 */
1065 
1066 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1067 /*
1068  Reads the given number of uncompressed bytes from the compressed file.
1069  If the input file was not in gzip format, gzread copies the given number
1070  of bytes into the buffer.
1071  gzread returns the number of uncompressed bytes actually read (0 for
1072  end of file, -1 for error). */
1073 
1074 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, voidpc buf, unsigned len));
1075 /*
1076  Writes the given number of uncompressed bytes into the compressed file.
1077  gzwrite returns the number of uncompressed bytes actually written
1078  (0 in case of error).
1079 */
1080 
1081 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char* format, ...));
1082 /*
1083  Converts, formats, and writes the args to the compressed file under
1084  control of the format string, as in fprintf. gzprintf returns the number of
1085  uncompressed bytes actually written (0 in case of error). The number of
1086  uncompressed bytes written is limited to 4095. The caller should assure that
1087  this limit is not exceeded. If it is exceeded, then gzprintf() will return
1088  return an error (0) with nothing written. In this case, there may also be a
1089  buffer overflow with unpredictable consequences, which is possible only if
1090  zlib was compiled with the insecure functions sprintf() or vsprintf()
1091  because the secure snprintf() or vsnprintf() functions were not available.
1092 */
1093 
1094 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char* s));
1095 /*
1096  Writes the given null-terminated string to the compressed file, excluding
1097  the terminating null character.
1098  gzputs returns the number of characters written, or -1 in case of error.
1099 */
1100 
1101 ZEXTERN char* ZEXPORT gzgets OF((gzFile file, char* buf, int len));
1102 /*
1103  Reads bytes from the compressed file until len-1 characters are read, or
1104  a newline character is read and transferred to buf, or an end-of-file
1105  condition is encountered. The string is then terminated with a null
1106  character.
1107  gzgets returns buf, or Z_NULL in case of error.
1108 */
1109 
1110 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1111 /*
1112  Writes c, converted to an unsigned char, into the compressed file.
1113  gzputc returns the value that was written, or -1 in case of error.
1114 */
1115 
1116 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1117 /*
1118  Reads one byte from the compressed file. gzgetc returns this byte
1119  or -1 in case of end of file or error.
1120 */
1121 
1122 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1123 /*
1124  Push one character back onto the stream to be read again later.
1125  Only one character of push-back is allowed. gzungetc() returns the
1126  character pushed, or -1 on failure. gzungetc() will fail if a
1127  character has been pushed but not read yet, or if c is -1. The pushed
1128  character will be discarded if the stream is repositioned with gzseek()
1129  or gzrewind().
1130 */
1131 
1132 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1133 /*
1134  Flushes all pending output into the compressed file. The parameter
1135  flush is as in the deflate() function. The return value is the zlib
1136  error number (see function gzerror below). gzflush returns Z_OK if
1137  the flush parameter is Z_FINISH and all output could be flushed.
1138  gzflush should be called only when strictly necessary because it can
1139  degrade compression.
1140 */
1141 
1142 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, z_off_t offset, int whence));
1143 /*
1144  Sets the starting position for the next gzread or gzwrite on the
1145  given compressed file. The offset represents a number of bytes in the
1146  uncompressed data stream. The whence parameter is defined as in lseek(2);
1147  the value SEEK_END is not supported.
1148  If the file is opened for reading, this function is emulated but can be
1149  extremely slow. If the file is opened for writing, only forward seeks are
1150  supported; gzseek then compresses a sequence of zeroes up to the new
1151  starting position.
1152 
1153  gzseek returns the resulting offset location as measured in bytes from
1154  the beginning of the uncompressed stream, or -1 in case of error, in
1155  particular if the file is opened for writing and the new starting position
1156  would be before the current position.
1157 */
1158 
1159 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1160 /*
1161  Rewinds the given file. This function is supported only for reading.
1162 
1163  gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1164 */
1165 
1166 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1167 /*
1168  Returns the starting position for the next gzread or gzwrite on the
1169  given compressed file. This position represents a number of bytes in the
1170  uncompressed data stream.
1171 
1172  gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1173 */
1174 
1175 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1176 /*
1177  Returns 1 when EOF has previously been detected reading the given
1178  input stream, otherwise zero.
1179 */
1180 
1181 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1182 /*
1183  Returns 1 if file is being read directly without decompression, otherwise
1184  zero.
1185 */
1186 
1187 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1188 /*
1189  Flushes all pending output if necessary, closes the compressed file
1190  and deallocates all the (de)compression state. The return value is the zlib
1191  error number (see function gzerror below).
1192 */
1193 
1194 ZEXTERN const char* ZEXPORT gzerror OF((gzFile file, int* errnum));
1195 /*
1196  Returns the error message for the last error which occurred on the
1197  given compressed file. errnum is set to zlib error number. If an
1198  error occurred in the file system and not in the compression library,
1199  errnum is set to Z_ERRNO and the application may consult errno
1200  to get the exact error code.
1201 */
1202 
1203 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1204 /*
1205  Clears the error and end-of-file flags for file. This is analogous to the
1206  clearerr() function in stdio. This is useful for continuing to read a gzip
1207  file that is being written concurrently.
1208 */
1209 
1210 /* checksum functions */
1211 
1212 /*
1213  These functions are not related to compression but are exported
1214  anyway because they might be useful in applications using the
1215  compression library.
1216 */
1217 
1218 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef* buf, uInt len));
1219 /*
1220  Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1221  return the updated checksum. If buf is nullptr, this function returns
1222  the required initial value for the checksum.
1223  An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1224  much faster. Usage example:
1225 
1226  uLong adler = adler32(0L, Z_NULL, 0);
1227 
1228  while (read_buffer(buffer, length) != EOF) {
1229  adler = adler32(adler, buffer, length);
1230  }
1231  if (adler != original_adler) error();
1232 */
1233 
1234 ZEXTERN uLong ZEXPORT adler32_combine
1235  OF((uLong adler1, uLong adler2, z_off_t len2));
1236 /*
1237  Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1238  and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1239  each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1240  seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
1241 */
1242 
1243 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef* buf, uInt len));
1244 /*
1245  Update a running CRC-32 with the bytes buf[0..len-1] and return the
1246  updated CRC-32. If buf is nullptr, this function returns the required initial
1247  value for the for the crc. Pre- and post-conditioning (one's complement) is
1248  performed within this function so it shouldn't be done by the application.
1249  Usage example:
1250 
1251  uLong crc = crc32(0L, Z_NULL, 0);
1252 
1253  while (read_buffer(buffer, length) != EOF) {
1254  crc = crc32(crc, buffer, length);
1255  }
1256  if (crc != original_crc) error();
1257 */
1258 
1259 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1260 
1261 /*
1262  Combine two CRC-32 check values into one. For two sequences of bytes,
1263  seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1264  calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1265  check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1266  len2.
1267 */
1268 
1269 /* various hacks, don't look :) */
1270 
1271 /* deflateInit and inflateInit are macros to allow checking the zlib version
1272  * and the compiler's view of z_stream:
1273  */
1274 ZEXTERN int ZEXPORT deflateInit_
1275  OF((z_streamp strm, int level, const char* version, int stream_size));
1276 ZEXTERN int ZEXPORT inflateInit_
1277  OF((z_streamp strm, const char* version, int stream_size));
1278 ZEXTERN int ZEXPORT deflateInit2_
1279  OF((z_streamp strm, int level, int method, int windowBits, int memLevel,
1280  int strategy, const char* version, int stream_size));
1281 ZEXTERN int ZEXPORT inflateInit2_
1282  OF((z_streamp strm, int windowBits, const char* version, int stream_size));
1283 ZEXTERN int ZEXPORT inflateBackInit_
1284  OF((z_streamp strm, int windowBits, unsigned char FAR* window,
1285  const char* version, int stream_size));
1286 #define deflateInit(strm, level) \
1287  deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
1288 #define inflateInit(strm) inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
1289 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1290  deflateInit2_( \
1291  (strm), (level), (method), (windowBits), (memLevel), (strategy), \
1292  ZLIB_VERSION, sizeof(z_stream))
1293 #define inflateInit2(strm, windowBits) \
1294  inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
1295 #define inflateBackInit(strm, windowBits, window) \
1296  inflateBackInit_( \
1297  (strm), (windowBits), (window), ZLIB_VERSION, sizeof(z_stream))
1298 
1299 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1300 struct internal_state
1301 {
1302  int dummy;
1303 }; /* hack for buggy compilers */
1304 #endif
1305 
1306 ZEXTERN const char* ZEXPORT zError OF((int));
1307 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
1308 ZEXTERN const uLongf* ZEXPORT get_crc_table OF((void));
1309 
1310 #ifdef __cplusplus
1311 }
1312 #endif
1313 
1314 #endif /* ZLIB_H */
int xflags
Definition: zlib.h:93
Bytef * extra
Definition: zlib.h:95
GLdouble GLdouble z
Definition: glext.h:3872
int text
Definition: zlib.h:91
Bytef * next_in
Definition: zlib.h:63
voidpf alloc_func OF((voidpf opaque, uInt items, uInt size))
Definition: zlib.h:56
int hcrc
Definition: zlib.h:102
uLong time
Definition: zlib.h:92
#define z_off_t
Definition: zconf.h:306
uInt avail_in
Definition: zlib.h:64
GLintptr offset
Definition: glext.h:3925
Bytef * name
Definition: zlib.h:98
uInt extra_max
Definition: zlib.h:97
char * msg
Definition: zlib.h:71
uInt name_max
Definition: zlib.h:99
int done
Definition: zlib.h:103
unsigned long uLong
Definition: zconf.h:269
struct gz_header_s gz_header
gz_header FAR * gz_headerp
Definition: zlib.h:107
GLdouble s
Definition: glext.h:3676
GLenum GLsizei len
Definition: glext.h:4712
Byte FAR Bytef
Definition: zconf.h:275
voidpf opaque
Definition: zlib.h:76
struct internal_state FAR * state
Definition: zlib.h:72
voidp gzFile
Definition: zlib.h:1026
free_func zfree
Definition: zlib.h:75
void * voidp
Definition: zconf.h:285
uLong reserved
Definition: zlib.h:80
uInt extra_len
Definition: zlib.h:96
const GLubyte * c
Definition: glext.h:6313
int data_type
Definition: zlib.h:78
int os
Definition: zlib.h:94
uLong total_in
Definition: zlib.h:65
alloc_func zalloc
Definition: zlib.h:74
Bytef * next_out
Definition: zlib.h:67
GLint mode
Definition: glext.h:5669
Bytef * comment
Definition: zlib.h:100
uLong adler
Definition: zlib.h:79
uLong total_out
Definition: zlib.h:69
void const * voidpc
Definition: zconf.h:283
#define ZEXTERN
Definition: zconf.h:252
uLong FAR uLongf
Definition: zconf.h:280
GLuint in
Definition: glext.h:7274
GLint level
Definition: glext.h:3600
GLsizei GLsizei GLchar * source
Definition: glext.h:4082
uInt comm_max
Definition: zlib.h:101
GLuint address
Definition: glext.h:6947
uInt avail_out
Definition: zlib.h:68
typedef void(APIENTRYP PFNGLBLENDCOLORPROC)(GLclampf red
GLenum GLsizei GLenum format
Definition: glext.h:3531
GLsizei const GLfloat * value
Definition: glext.h:4117
void compress(void *inData, size_t inDataSize, std::vector< unsigned char > &outData)
Compress an array of bytes into another one.
Definition: zip.cpp:36
GLsizeiptr size
Definition: glext.h:3923
struct z_stream_s z_stream
#define FAR
Definition: zconf.h:262
z_stream FAR * z_streamp
Definition: zlib.h:83
void FAR * voidpf
Definition: zconf.h:284
#define ZEXPORT
Definition: zconf.h:255
#define ZEXPORTVA
Definition: zconf.h:258
unsigned int uInt
Definition: zconf.h:268



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