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zlib.h
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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  Bytef *next_in; /* next input byte */
63  uInt avail_in; /* number of bytes available at next_in */
64  uLong total_in; /* total nb of input bytes read so far */
65 
66  Bytef *next_out; /* next output byte should be put there */
67  uInt avail_out; /* remaining free space at next_out */
68  uLong total_out; /* total nb of bytes output so far */
69 
70  char *msg; /* last error message, NULL if no error */
71  struct internal_state FAR *state; /* not visible by applications */
72 
73  alloc_func zalloc; /* used to allocate the internal state */
74  free_func zfree; /* used to free the internal state */
75  voidpf opaque; /* private data object passed to zalloc and zfree */
76 
77  int data_type; /* best guess about the data type: binary or text */
78  uLong adler; /* adler32 value of the uncompressed data */
79  uLong reserved; /* reserved for future use */
80 } z_stream;
81 
83 
84 /*
85  gzip header information passed to and from zlib routines. See RFC 1952
86  for more details on the meanings of these fields.
87 */
88 typedef struct gz_header_s {
89  int text; /* true if compressed data believed to be text */
90  uLong time; /* modification time */
91  int xflags; /* extra flags (not used when writing a gzip file) */
92  int os; /* operating system */
93  Bytef *extra; /* pointer to extra field or Z_NULL if none */
94  uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
95  uInt extra_max; /* space at extra (only when reading header) */
96  Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
97  uInt name_max; /* space at name (only when reading header) */
98  Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
99  uInt comm_max; /* space at comment (only when reading header) */
100  int hcrc; /* true if there was or will be a header crc */
101  int done; /* true when done reading gzip header (not used
102  when writing a gzip file) */
103 } gz_header;
104 
106 
107 /*
108  The application must update next_in and avail_in when avail_in has
109  dropped to zero. It must update next_out and avail_out when avail_out
110  has dropped to zero. The application must initialize zalloc, zfree and
111  opaque before calling the init function. All other fields are set by the
112  compression library and must not be updated by the application.
113 
114  The opaque value provided by the application will be passed as the first
115  parameter for calls of zalloc and zfree. This can be useful for custom
116  memory management. The compression library attaches no meaning to the
117  opaque value.
118 
119  zalloc must return Z_NULL if there is not enough memory for the object.
120  If zlib is used in a multi-threaded application, zalloc and zfree must be
121  thread safe.
122 
123  On 16-bit systems, the functions zalloc and zfree must be able to allocate
124  exactly 65536 bytes, but will not be required to allocate more than this
125  if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
126  pointers returned by zalloc for objects of exactly 65536 bytes *must*
127  have their offset normalized to zero. The default allocation function
128  provided by this library ensures this (see zutil.c). To reduce memory
129  requirements and avoid any allocation of 64K objects, at the expense of
130  compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
131 
132  The fields total_in and total_out can be used for statistics or
133  progress reports. After compression, total_in holds the total size of
134  the uncompressed data and may be saved for use in the decompressor
135  (particularly if the decompressor wants to decompress everything in
136  a single step).
137 */
138 
139  /* constants */
140 
141 #define Z_NO_FLUSH 0
142 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
143 #define Z_SYNC_FLUSH 2
144 #define Z_FULL_FLUSH 3
145 #define Z_FINISH 4
146 #define Z_BLOCK 5
147 /* Allowed flush values; see deflate() and inflate() below for details */
148 
149 #define Z_OK 0
150 #define Z_STREAM_END 1
151 #define Z_NEED_DICT 2
152 #define Z_ERRNO (-1)
153 #define Z_STREAM_ERROR (-2)
154 #define Z_DATA_ERROR (-3)
155 #define Z_MEM_ERROR (-4)
156 #define Z_BUF_ERROR (-5)
157 #define Z_VERSION_ERROR (-6)
158 /* Return codes for the compression/decompression functions. Negative
159  * values are errors, positive values are used for special but normal events.
160  */
161 
162 #define Z_NO_COMPRESSION 0
163 #define Z_BEST_SPEED 1
164 #define Z_BEST_COMPRESSION 9
165 #define Z_DEFAULT_COMPRESSION (-1)
166 /* compression levels */
167 
168 #define Z_FILTERED 1
169 #define Z_HUFFMAN_ONLY 2
170 #define Z_RLE 3
171 #define Z_FIXED 4
172 #define Z_DEFAULT_STRATEGY 0
173 /* compression strategy; see deflateInit2() below for details */
174 
175 #define Z_BINARY 0
176 #define Z_TEXT 1
177 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
178 #define Z_UNKNOWN 2
179 /* Possible values of the data_type field (though see inflate()) */
180 
181 #define Z_DEFLATED 8
182 /* The deflate compression method (the only one supported in this version) */
183 
184 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
185 
186 #define zlib_version zlibVersion()
187 /* for compatibility with versions < 1.0.2 */
188 
189  /* basic functions */
190 
191 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
192 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
193  If the first character differs, the library code actually used is
194  not compatible with the zlib.h header file used by the application.
195  This check is automatically made by deflateInit and inflateInit.
196  */
197 
198 /*
199 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
200 
201  Initializes the internal stream state for compression. The fields
202  zalloc, zfree and opaque must be initialized before by the caller.
203  If zalloc and zfree are set to Z_NULL, deflateInit updates them to
204  use default allocation functions.
205 
206  The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
207  1 gives best speed, 9 gives best compression, 0 gives no compression at
208  all (the input data is simply copied a block at a time).
209  Z_DEFAULT_COMPRESSION requests a default compromise between speed and
210  compression (currently equivalent to level 6).
211 
212  deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
213  enough memory, Z_STREAM_ERROR if level is not a valid compression level,
214  Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
215  with the version assumed by the caller (ZLIB_VERSION).
216  msg is set to null if there is no error message. deflateInit does not
217  perform any compression: this will be done by deflate().
218 */
219 
220 
221 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
222 /*
223  deflate compresses as much data as possible, and stops when the input
224  buffer becomes empty or the output buffer becomes full. It may introduce some
225  output latency (reading input without producing any output) except when
226  forced to flush.
227 
228  The detailed semantics are as follows. deflate performs one or both of the
229  following actions:
230 
231  - Compress more input starting at next_in and update next_in and avail_in
232  accordingly. If not all input can be processed (because there is not
233  enough room in the output buffer), next_in and avail_in are updated and
234  processing will resume at this point for the next call of deflate().
235 
236  - Provide more output starting at next_out and update next_out and avail_out
237  accordingly. This action is forced if the parameter flush is non zero.
238  Forcing flush frequently degrades the compression ratio, so this parameter
239  should be set only when necessary (in interactive applications).
240  Some output may be provided even if flush is not set.
241 
242  Before the call of deflate(), the application should ensure that at least
243  one of the actions is possible, by providing more input and/or consuming
244  more output, and updating avail_in or avail_out accordingly; avail_out
245  should never be zero before the call. The application can consume the
246  compressed output when it wants, for example when the output buffer is full
247  (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
248  and with zero avail_out, it must be called again after making room in the
249  output buffer because there might be more output pending.
250 
251  Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
252  decide how much data to accumualte before producing output, in order to
253  maximize compression.
254 
255  If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
256  flushed to the output buffer and the output is aligned on a byte boundary, so
257  that the decompressor can get all input data available so far. (In particular
258  avail_in is zero after the call if enough output space has been provided
259  before the call.) Flushing may degrade compression for some compression
260  algorithms and so it should be used only when necessary.
261 
262  If flush is set to Z_FULL_FLUSH, all output is flushed as with
263  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
264  restart from this point if previous compressed data has been damaged or if
265  random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
266  compression.
267 
268  If deflate returns with avail_out == 0, this function must be called again
269  with the same value of the flush parameter and more output space (updated
270  avail_out), until the flush is complete (deflate returns with non-zero
271  avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
272  avail_out is greater than six to avoid repeated flush markers due to
273  avail_out == 0 on return.
274 
275  If the parameter flush is set to Z_FINISH, pending input is processed,
276  pending output is flushed and deflate returns with Z_STREAM_END if there
277  was enough output space; if deflate returns with Z_OK, this function must be
278  called again with Z_FINISH and more output space (updated avail_out) but no
279  more input data, until it returns with Z_STREAM_END or an error. After
280  deflate has returned Z_STREAM_END, the only possible operations on the
281  stream are deflateReset or deflateEnd.
282 
283  Z_FINISH can be used immediately after deflateInit if all the compression
284  is to be done in a single step. In this case, avail_out must be at least
285  the value returned by deflateBound (see below). If deflate does not return
286  Z_STREAM_END, then it must be called again as described above.
287 
288  deflate() sets strm->adler to the adler32 checksum of all input read
289  so far (that is, total_in bytes).
290 
291  deflate() may update strm->data_type if it can make a good guess about
292  the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
293  binary. This field is only for information purposes and does not affect
294  the compression algorithm in any manner.
295 
296  deflate() returns Z_OK if some progress has been made (more input
297  processed or more output produced), Z_STREAM_END if all input has been
298  consumed and all output has been produced (only when flush is set to
299  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
300  if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
301  (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
302  fatal, and deflate() can be called again with more input and more output
303  space to continue compressing.
304 */
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 /*
322 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
323 
324  Initializes the internal stream state for decompression. The fields
325  next_in, avail_in, zalloc, zfree and opaque must be initialized before by
326  the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
327  value depends on the compression method), inflateInit determines the
328  compression method from the zlib header and allocates all data structures
329  accordingly; otherwise the allocation will be deferred to the first call of
330  inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
331  use default allocation functions.
332 
333  inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
334  memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
335  version assumed by the caller. msg is set to null if there is no error
336  message. inflateInit does not perform any decompression apart from reading
337  the zlib header if present: this will be done by inflate(). (So next_in and
338  avail_in may be modified, but next_out and avail_out are unchanged.)
339 */
340 
341 
342 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
343 /*
344  inflate decompresses as much data as possible, and stops when the input
345  buffer becomes empty or the output buffer becomes full. It may introduce
346  some output latency (reading input without producing any output) except when
347  forced to flush.
348 
349  The detailed semantics are as follows. inflate performs one or both of the
350  following actions:
351 
352  - Decompress more input starting at next_in and update next_in and avail_in
353  accordingly. If not all input can be processed (because there is not
354  enough room in the output buffer), next_in is updated and processing
355  will resume at this point for the next call of inflate().
356 
357  - Provide more output starting at next_out and update next_out and avail_out
358  accordingly. inflate() provides as much output as possible, until there
359  is no more input data or no more space in the output buffer (see below
360  about the flush parameter).
361 
362  Before the call of inflate(), the application should ensure that at least
363  one of the actions is possible, by providing more input and/or consuming
364  more output, and updating the next_* and avail_* values accordingly.
365  The application can consume the uncompressed output when it wants, for
366  example when the output buffer is full (avail_out == 0), or after each
367  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
368  must be called again after making room in the output buffer because there
369  might be more output pending.
370 
371  The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
372  Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
373  output as possible to the output buffer. Z_BLOCK requests that inflate() stop
374  if and when it gets to the next deflate block boundary. When decoding the
375  zlib or gzip format, this will cause inflate() to return immediately after
376  the header and before the first block. When doing a raw inflate, inflate()
377  will go ahead and process the first block, and will return when it gets to
378  the end of that block, or when it runs out of data.
379 
380  The Z_BLOCK option assists in appending to or combining deflate streams.
381  Also to assist in this, on return inflate() will set strm->data_type to the
382  number of unused bits in the last byte taken from strm->next_in, plus 64
383  if inflate() is currently decoding the last block in the deflate stream,
384  plus 128 if inflate() returned immediately after decoding an end-of-block
385  code or decoding the complete header up to just before the first byte of the
386  deflate stream. The end-of-block will not be indicated until all of the
387  uncompressed data from that block has been written to strm->next_out. The
388  number of unused bits may in general be greater than seven, except when
389  bit 7 of data_type is set, in which case the number of unused bits will be
390  less than eight.
391 
392  inflate() should normally be called until it returns Z_STREAM_END or an
393  error. However if all decompression is to be performed in a single step
394  (a single call of inflate), the parameter flush should be set to
395  Z_FINISH. In this case all pending input is processed and all pending
396  output is flushed; avail_out must be large enough to hold all the
397  uncompressed data. (The size of the uncompressed data may have been saved
398  by the compressor for this purpose.) The next operation on this stream must
399  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
400  is never required, but can be used to inform inflate that a faster approach
401  may be used for the single inflate() call.
402 
403  In this implementation, inflate() always flushes as much output as
404  possible to the output buffer, and always uses the faster approach on the
405  first call. So the only effect of the flush parameter in this implementation
406  is on the return value of inflate(), as noted below, or when it returns early
407  because Z_BLOCK is used.
408 
409  If a preset dictionary is needed after this call (see inflateSetDictionary
410  below), inflate sets strm->adler to the adler32 checksum of the dictionary
411  chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
412  strm->adler to the adler32 checksum of all output produced so far (that is,
413  total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
414  below. At the end of the stream, inflate() checks that its computed adler32
415  checksum is equal to that saved by the compressor and returns Z_STREAM_END
416  only if the checksum is correct.
417 
418  inflate() will decompress and check either zlib-wrapped or gzip-wrapped
419  deflate data. The header type is detected automatically. Any information
420  contained in the gzip header is not retained, so applications that need that
421  information should instead use raw inflate, see inflateInit2() below, or
422  inflateBack() and perform their own processing of the gzip header and
423  trailer.
424 
425  inflate() returns Z_OK if some progress has been made (more input processed
426  or more output produced), Z_STREAM_END if the end of the compressed data has
427  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
428  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
429  corrupted (input stream not conforming to the zlib format or incorrect check
430  value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
431  if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
432  Z_BUF_ERROR if no progress is possible or if there was not enough room in the
433  output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
434  inflate() can be called again with more input and more output space to
435  continue decompressing. If Z_DATA_ERROR is returned, the application may then
436  call inflateSync() to look for a good compression block if a partial recovery
437  of the data is desired.
438 */
439 
440 
441 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
442 /*
443  All dynamically allocated data structures for this stream are freed.
444  This function discards any unprocessed input and does not flush any
445  pending output.
446 
447  inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
448  was inconsistent. In the error case, msg may be set but then points to a
449  static string (which must not be deallocated).
450 */
451 
452  /* Advanced functions */
453 
454 /*
455  The following functions are needed only in some special applications.
456 */
457 
458 /*
459 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
460  int level,
461  int method,
462  int windowBits,
463  int memLevel,
464  int strategy));
465 
466  This is another version of deflateInit with more compression options. The
467  fields next_in, zalloc, zfree and opaque must be initialized before by
468  the caller.
469 
470  The method parameter is the compression method. It must be Z_DEFLATED in
471  this version of the library.
472 
473  The windowBits parameter is the base two logarithm of the window size
474  (the size of the history buffer). It should be in the range 8..15 for this
475  version of the library. Larger values of this parameter result in better
476  compression at the expense of memory usage. The default value is 15 if
477  deflateInit is used instead.
478 
479  windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
480  determines the window size. deflate() will then generate raw deflate data
481  with no zlib header or trailer, and will not compute an adler32 check value.
482 
483  windowBits can also be greater than 15 for optional gzip encoding. Add
484  16 to windowBits to write a simple gzip header and trailer around the
485  compressed data instead of a zlib wrapper. The gzip header will have no
486  file name, no extra data, no comment, no modification time (set to zero),
487  no header crc, and the operating system will be set to 255 (unknown). If a
488  gzip stream is being written, strm->adler is a crc32 instead of an adler32.
489 
490  The memLevel parameter specifies how much memory should be allocated
491  for the internal compression state. memLevel=1 uses minimum memory but
492  is slow and reduces compression ratio; memLevel=9 uses maximum memory
493  for optimal speed. The default value is 8. See zconf.h for total memory
494  usage as a function of windowBits and memLevel.
495 
496  The strategy parameter is used to tune the compression algorithm. Use the
497  value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
498  filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
499  string match), or Z_RLE to limit match distances to one (run-length
500  encoding). Filtered data consists mostly of small values with a somewhat
501  random distribution. In this case, the compression algorithm is tuned to
502  compress them better. The effect of Z_FILTERED is to force more Huffman
503  coding and less string matching; it is somewhat intermediate between
504  Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
505  Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
506  parameter only affects the compression ratio but not the correctness of the
507  compressed output even if it is not set appropriately. Z_FIXED prevents the
508  use of dynamic Huffman codes, allowing for a simpler decoder for special
509  applications.
510 
511  deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
512  memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
513  method). msg is set to null if there is no error message. deflateInit2 does
514  not perform any compression: this will be done by deflate().
515 */
516 
517 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
518  const Bytef *dictionary,
519  uInt dictLength));
520 /*
521  Initializes the compression dictionary from the given byte sequence
522  without producing any compressed output. This function must be called
523  immediately after deflateInit, deflateInit2 or deflateReset, before any
524  call of deflate. The compressor and decompressor must use exactly the same
525  dictionary (see inflateSetDictionary).
526 
527  The dictionary should consist of strings (byte sequences) that are likely
528  to be encountered later in the data to be compressed, with the most commonly
529  used strings preferably put towards the end of the dictionary. Using a
530  dictionary is most useful when the data to be compressed is short and can be
531  predicted with good accuracy; the data can then be compressed better than
532  with the default empty dictionary.
533 
534  Depending on the size of the compression data structures selected by
535  deflateInit or deflateInit2, a part of the dictionary may in effect be
536  discarded, for example if the dictionary is larger than the window size in
537  deflate or deflate2. Thus the strings most likely to be useful should be
538  put at the end of the dictionary, not at the front. In addition, the
539  current implementation of deflate will use at most the window size minus
540  262 bytes of the provided dictionary.
541 
542  Upon return of this function, strm->adler is set to the adler32 value
543  of the dictionary; the decompressor may later use this value to determine
544  which dictionary has been used by the compressor. (The adler32 value
545  applies to the whole dictionary even if only a subset of the dictionary is
546  actually used by the compressor.) If a raw deflate was requested, then the
547  adler32 value is not computed and strm->adler is not set.
548 
549  deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
550  parameter is invalid (such as NULL dictionary) or the stream state is
551  inconsistent (for example if deflate has already been called for this stream
552  or if the compression method is bsort). deflateSetDictionary does not
553  perform any compression: this will be done by deflate().
554 */
555 
556 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
557  z_streamp source));
558 /*
559  Sets the destination stream as a complete copy of the source stream.
560 
561  This function can be useful when several compression strategies will be
562  tried, for example when there are several ways of pre-processing the input
563  data with a filter. The streams that will be discarded should then be freed
564  by calling deflateEnd. Note that deflateCopy duplicates the internal
565  compression state which can be quite large, so this strategy is slow and
566  can consume lots of memory.
567 
568  deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
569  enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
570  (such as zalloc being NULL). msg is left unchanged in both source and
571  destination.
572 */
573 
574 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
575 /*
576  This function is equivalent to deflateEnd followed by deflateInit,
577  but does not free and reallocate all the internal compression state.
578  The stream will keep the same compression level and any other attributes
579  that may have been set by deflateInit2.
580 
581  deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
582  stream state was inconsistent (such as zalloc or state being NULL).
583 */
584 
585 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
586  int level,
587  int strategy));
588 /*
589  Dynamically update the compression level and compression strategy. The
590  interpretation of level and strategy is as in deflateInit2. This can be
591  used to switch between compression and straight copy of the input data, or
592  to switch to a different kind of input data requiring a different
593  strategy. If the compression level is changed, the input available so far
594  is compressed with the old level (and may be flushed); the new level will
595  take effect only at the next call of deflate().
596 
597  Before the call of deflateParams, the stream state must be set as for
598  a call of deflate(), since the currently available input may have to
599  be compressed and flushed. In particular, strm->avail_out must be non-zero.
600 
601  deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
602  stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
603  if strm->avail_out was zero.
604 */
605 
606 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
607  int good_length,
608  int max_lazy,
609  int nice_length,
610  int max_chain));
611 /*
612  Fine tune deflate's internal compression parameters. This should only be
613  used by someone who understands the algorithm used by zlib's deflate for
614  searching for the best matching string, and even then only by the most
615  fanatic optimizer trying to squeeze out the last compressed bit for their
616  specific input data. Read the deflate.c source code for the meaning of the
617  max_lazy, good_length, nice_length, and max_chain parameters.
618 
619  deflateTune() can be called after deflateInit() or deflateInit2(), and
620  returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
621  */
622 
623 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
624  uLong sourceLen));
625 /*
626  deflateBound() returns an upper bound on the compressed size after
627  deflation of sourceLen bytes. It must be called after deflateInit()
628  or deflateInit2(). This would be used to allocate an output buffer
629  for deflation in a single pass, and so would be called before deflate().
630 */
631 
632 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
633  int bits,
634  int value));
635 /*
636  deflatePrime() inserts bits in the deflate output stream. The intent
637  is that this function is used to start off the deflate output with the
638  bits leftover from a previous deflate stream when appending to it. As such,
639  this function can only be used for raw deflate, and must be used before the
640  first deflate() call after a deflateInit2() or deflateReset(). bits must be
641  less than or equal to 16, and that many of the least significant bits of
642  value will be inserted in the output.
643 
644  deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
645  stream state was inconsistent.
646 */
647 
648 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
649  gz_headerp head));
650 /*
651  deflateSetHeader() provides gzip header information for when a gzip
652  stream is requested by deflateInit2(). deflateSetHeader() may be called
653  after deflateInit2() or deflateReset() and before the first call of
654  deflate(). The text, time, os, extra field, name, and comment information
655  in the provided gz_header structure are written to the gzip header (xflag is
656  ignored -- the extra flags are set according to the compression level). The
657  caller must assure that, if not Z_NULL, name and comment are terminated with
658  a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
659  available there. If hcrc is true, a gzip header crc is included. Note that
660  the current versions of the command-line version of gzip (up through version
661  1.3.x) do not support header crc's, and will report that it is a "multi-part
662  gzip file" and give up.
663 
664  If deflateSetHeader is not used, the default gzip header has text false,
665  the time set to zero, and os set to 255, with no extra, name, or comment
666  fields. The gzip header is returned to the default state by deflateReset().
667 
668  deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
669  stream state was inconsistent.
670 */
671 
672 /*
673 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
674  int windowBits));
675 
676  This is another version of inflateInit with an extra parameter. The
677  fields next_in, avail_in, zalloc, zfree and opaque must be initialized
678  before by the caller.
679 
680  The windowBits parameter is the base two logarithm of the maximum window
681  size (the size of the history buffer). It should be in the range 8..15 for
682  this version of the library. The default value is 15 if inflateInit is used
683  instead. windowBits must be greater than or equal to the windowBits value
684  provided to deflateInit2() while compressing, or it must be equal to 15 if
685  deflateInit2() was not used. If a compressed stream with a larger window
686  size is given as input, inflate() will return with the error code
687  Z_DATA_ERROR instead of trying to allocate a larger window.
688 
689  windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
690  determines the window size. inflate() will then process raw deflate data,
691  not looking for a zlib or gzip header, not generating a check value, and not
692  looking for any check values for comparison at the end of the stream. This
693  is for use with other formats that use the deflate compressed data format
694  such as zip. Those formats provide their own check values. If a custom
695  format is developed using the raw deflate format for compressed data, it is
696  recommended that a check value such as an adler32 or a crc32 be applied to
697  the uncompressed data as is done in the zlib, gzip, and zip formats. For
698  most applications, the zlib format should be used as is. Note that comments
699  above on the use in deflateInit2() applies to the magnitude of windowBits.
700 
701  windowBits can also be greater than 15 for optional gzip decoding. Add
702  32 to windowBits to enable zlib and gzip decoding with automatic header
703  detection, or add 16 to decode only the gzip format (the zlib format will
704  return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
705  a crc32 instead of an adler32.
706 
707  inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
708  memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
709  is set to null if there is no error message. inflateInit2 does not perform
710  any decompression apart from reading the zlib header if present: this will
711  be done by inflate(). (So next_in and avail_in may be modified, but next_out
712  and avail_out are unchanged.)
713 */
714 
715 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
716  const Bytef *dictionary,
717  uInt dictLength));
718 /*
719  Initializes the decompression dictionary from the given uncompressed byte
720  sequence. This function must be called immediately after a call of inflate,
721  if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
722  can be determined from the adler32 value returned by that call of inflate.
723  The compressor and decompressor must use exactly the same dictionary (see
724  deflateSetDictionary). For raw inflate, this function can be called
725  immediately after inflateInit2() or inflateReset() and before any call of
726  inflate() to set the dictionary. The application must insure that the
727  dictionary that was used for compression is provided.
728 
729  inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
730  parameter is invalid (such as NULL dictionary) or the stream state is
731  inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
732  expected one (incorrect adler32 value). inflateSetDictionary does not
733  perform any decompression: this will be done by subsequent calls of
734  inflate().
735 */
736 
737 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
738 /*
739  Skips invalid compressed data until a full flush point (see above the
740  description of deflate with Z_FULL_FLUSH) can be found, or until all
741  available input is skipped. No output is provided.
742 
743  inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
744  if no more input was provided, Z_DATA_ERROR if no flush point has been found,
745  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
746  case, the application may save the current current value of total_in which
747  indicates where valid compressed data was found. In the error case, the
748  application may repeatedly call inflateSync, providing more input each time,
749  until success or end of the input data.
750 */
751 
752 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
753  z_streamp source));
754 /*
755  Sets the destination stream as a complete copy of the source stream.
756 
757  This function can be useful when randomly accessing a large stream. The
758  first pass through the stream can periodically record the inflate state,
759  allowing restarting inflate at those points when randomly accessing the
760  stream.
761 
762  inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
763  enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
764  (such as zalloc being NULL). msg is left unchanged in both source and
765  destination.
766 */
767 
768 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
769 /*
770  This function is equivalent to inflateEnd followed by inflateInit,
771  but does not free and reallocate all the internal decompression state.
772  The stream will keep attributes that may have been set by inflateInit2.
773 
774  inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
775  stream state was inconsistent (such as zalloc or state being NULL).
776 */
777 
778 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
779  int bits,
780  int value));
781 /*
782  This function inserts bits in the inflate input stream. The intent is
783  that this function is used to start inflating at a bit position in the
784  middle of a byte. The provided bits will be used before any bytes are used
785  from next_in. This function should only be used with raw inflate, and
786  should be used before the first inflate() call after inflateInit2() or
787  inflateReset(). bits must be less than or equal to 16, and that many of the
788  least significant bits of value will be inserted in the input.
789 
790  inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
791  stream state was inconsistent.
792 */
793 
794 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
795  gz_headerp head));
796 /*
797  inflateGetHeader() requests that gzip header information be stored in the
798  provided gz_header structure. inflateGetHeader() may be called after
799  inflateInit2() or inflateReset(), and before the first call of inflate().
800  As inflate() processes the gzip stream, head->done is zero until the header
801  is completed, at which time head->done is set to one. If a zlib stream is
802  being decoded, then head->done is set to -1 to indicate that there will be
803  no gzip header information forthcoming. Note that Z_BLOCK can be used to
804  force inflate() to return immediately after header processing is complete
805  and before any actual data is decompressed.
806 
807  The text, time, xflags, and os fields are filled in with the gzip header
808  contents. hcrc is set to true if there is a header CRC. (The header CRC
809  was valid if done is set to one.) If extra is not Z_NULL, then extra_max
810  contains the maximum number of bytes to write to extra. Once done is true,
811  extra_len contains the actual extra field length, and extra contains the
812  extra field, or that field truncated if extra_max is less than extra_len.
813  If name is not Z_NULL, then up to name_max characters are written there,
814  terminated with a zero unless the length is greater than name_max. If
815  comment is not Z_NULL, then up to comm_max characters are written there,
816  terminated with a zero unless the length is greater than comm_max. When
817  any of extra, name, or comment are not Z_NULL and the respective field is
818  not present in the header, then that field is set to Z_NULL to signal its
819  absence. This allows the use of deflateSetHeader() with the returned
820  structure to duplicate the header. However if those fields are set to
821  allocated memory, then the application will need to save those pointers
822  elsewhere so that they can be eventually freed.
823 
824  If inflateGetHeader is not used, then the header information is simply
825  discarded. The header is always checked for validity, including the header
826  CRC if present. inflateReset() will reset the process to discard the header
827  information. The application would need to call inflateGetHeader() again to
828  retrieve the header from the next gzip stream.
829 
830  inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
831  stream state was inconsistent.
832 */
833 
834 /*
835 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
836  unsigned char FAR *window));
837 
838  Initialize the internal stream state for decompression using inflateBack()
839  calls. The fields zalloc, zfree and opaque in strm must be initialized
840  before the call. If zalloc and zfree are Z_NULL, then the default library-
841  derived memory allocation routines are used. windowBits is the base two
842  logarithm of the window size, in the range 8..15. window is a caller
843  supplied buffer of that size. Except for special applications where it is
844  assured that deflate was used with small window sizes, windowBits must be 15
845  and a 32K byte window must be supplied to be able to decompress general
846  deflate streams.
847 
848  See inflateBack() for the usage of these routines.
849 
850  inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
851  the paramaters are invalid, Z_MEM_ERROR if the internal state could not
852  be allocated, or Z_VERSION_ERROR if the version of the library does not
853  match the version of the header file.
854 */
855 
856 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
857 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
858 
859 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
860  in_func in, void FAR *in_desc,
861  out_func out, void FAR *out_desc));
862 /*
863  inflateBack() does a raw inflate with a single call using a call-back
864  interface for input and output. This is more efficient than inflate() for
865  file i/o applications in that it avoids copying between the output and the
866  sliding window by simply making the window itself the output buffer. This
867  function trusts the application to not change the output buffer passed by
868  the output function, at least until inflateBack() returns.
869 
870  inflateBackInit() must be called first to allocate the internal state
871  and to initialize the state with the user-provided window buffer.
872  inflateBack() may then be used multiple times to inflate a complete, raw
873  deflate stream with each call. inflateBackEnd() is then called to free
874  the allocated state.
875 
876  A raw deflate stream is one with no zlib or gzip header or trailer.
877  This routine would normally be used in a utility that reads zip or gzip
878  files and writes out uncompressed files. The utility would decode the
879  header and process the trailer on its own, hence this routine expects
880  only the raw deflate stream to decompress. This is different from the
881  normal behavior of inflate(), which expects either a zlib or gzip header and
882  trailer around the deflate stream.
883 
884  inflateBack() uses two subroutines supplied by the caller that are then
885  called by inflateBack() for input and output. inflateBack() calls those
886  routines until it reads a complete deflate stream and writes out all of the
887  uncompressed data, or until it encounters an error. The function's
888  parameters and return types are defined above in the in_func and out_func
889  typedefs. inflateBack() will call in(in_desc, &buf) which should return the
890  number of bytes of provided input, and a pointer to that input in buf. If
891  there is no input available, in() must return zero--buf is ignored in that
892  case--and inflateBack() will return a buffer error. inflateBack() will call
893  out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
894  should return zero on success, or non-zero on failure. If out() returns
895  non-zero, inflateBack() will return with an error. Neither in() nor out()
896  are permitted to change the contents of the window provided to
897  inflateBackInit(), which is also the buffer that out() uses to write from.
898  The length written by out() will be at most the window size. Any non-zero
899  amount of input may be provided by in().
900 
901  For convenience, inflateBack() can be provided input on the first call by
902  setting strm->next_in and strm->avail_in. If that input is exhausted, then
903  in() will be called. Therefore strm->next_in must be initialized before
904  calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
905  immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
906  must also be initialized, and then if strm->avail_in is not zero, input will
907  initially be taken from strm->next_in[0 .. strm->avail_in - 1].
908 
909  The in_desc and out_desc parameters of inflateBack() is passed as the
910  first parameter of in() and out() respectively when they are called. These
911  descriptors can be optionally used to pass any information that the caller-
912  supplied in() and out() functions need to do their job.
913 
914  On return, inflateBack() will set strm->next_in and strm->avail_in to
915  pass back any unused input that was provided by the last in() call. The
916  return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
917  if in() or out() returned an error, Z_DATA_ERROR if there was a format
918  error in the deflate stream (in which case strm->msg is set to indicate the
919  nature of the error), or Z_STREAM_ERROR if the stream was not properly
920  initialized. In the case of Z_BUF_ERROR, an input or output error can be
921  distinguished using strm->next_in which will be Z_NULL only if in() returned
922  an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
923  out() returning non-zero. (in() will always be called before out(), so
924  strm->next_in is assured to be defined if out() returns non-zero.) Note
925  that inflateBack() cannot return Z_OK.
926 */
927 
928 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
929 /*
930  All memory allocated by inflateBackInit() is freed.
931 
932  inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
933  state was inconsistent.
934 */
935 
936 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
937 /* Return flags indicating compile-time options.
938 
939  Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
940  1.0: size of uInt
941  3.2: size of uLong
942  5.4: size of voidpf (pointer)
943  7.6: size of z_off_t
944 
945  Compiler, assembler, and debug options:
946  8: DEBUG
947  9: ASMV or ASMINF -- use ASM code
948  10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
949  11: 0 (reserved)
950 
951  One-time table building (smaller code, but not thread-safe if true):
952  12: BUILDFIXED -- build static block decoding tables when needed
953  13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
954  14,15: 0 (reserved)
955 
956  Library content (indicates missing functionality):
957  16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
958  deflate code when not needed)
959  17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
960  and decode gzip streams (to avoid linking crc code)
961  18-19: 0 (reserved)
962 
963  Operation variations (changes in library functionality):
964  20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
965  21: FASTEST -- deflate algorithm with only one, lowest compression level
966  22,23: 0 (reserved)
967 
968  The sprintf variant used by gzprintf (zero is best):
969  24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
970  25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
971  26: 0 = returns value, 1 = void -- 1 means inferred string length returned
972 
973  Remainder:
974  27-31: 0 (reserved)
975  */
976 
977 
978  /* utility functions */
979 
980 /*
981  The following utility functions are implemented on top of the
982  basic stream-oriented functions. To simplify the interface, some
983  default options are assumed (compression level and memory usage,
984  standard memory allocation functions). The source code of these
985  utility functions can easily be modified if you need special options.
986 */
987 
988 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
989  const Bytef *source, uLong sourceLen));
990 /*
991  Compresses the source buffer into the destination buffer. sourceLen is
992  the byte length of the source buffer. Upon entry, destLen is the total
993  size of the destination buffer, which must be at least the value returned
994  by compressBound(sourceLen). Upon exit, destLen is the actual size of the
995  compressed buffer.
996  This function can be used to compress a whole file at once if the
997  input file is mmap'ed.
998  compress returns Z_OK if success, Z_MEM_ERROR if there was not
999  enough memory, Z_BUF_ERROR if there was not enough room in the output
1000  buffer.
1001 */
1002 
1003 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1004  const Bytef *source, uLong sourceLen,
1005  int level));
1006 /*
1007  Compresses the source buffer into the destination buffer. The level
1008  parameter has the same meaning as in deflateInit. sourceLen is the byte
1009  length of the source buffer. Upon entry, destLen is the total size of the
1010  destination buffer, which must be at least the value returned by
1011  compressBound(sourceLen). Upon exit, destLen is the actual size of the
1012  compressed buffer.
1013 
1014  compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1015  memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1016  Z_STREAM_ERROR if the level parameter is invalid.
1017 */
1018 
1019 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1020 /*
1021  compressBound() returns an upper bound on the compressed size after
1022  compress() or compress2() on sourceLen bytes. It would be used before
1023  a compress() or compress2() call to allocate the destination buffer.
1024 */
1025 
1026 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1027  const Bytef *source, uLong sourceLen));
1028 /*
1029  Decompresses the source buffer into the destination buffer. sourceLen is
1030  the byte length of the source buffer. Upon entry, destLen is the total
1031  size of the destination buffer, which must be large enough to hold the
1032  entire uncompressed data. (The size of the uncompressed data must have
1033  been saved previously by the compressor and transmitted to the decompressor
1034  by some mechanism outside the scope of this compression library.)
1035  Upon exit, destLen is the actual size of the compressed buffer.
1036  This function can be used to decompress a whole file at once if the
1037  input file is mmap'ed.
1038 
1039  uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1040  enough memory, Z_BUF_ERROR if there was not enough room in the output
1041  buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
1042 */
1043 
1044 
1045 typedef voidp gzFile;
1046 
1047 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1048 /*
1049  Opens a gzip (.gz) file for reading or writing. The mode parameter
1050  is as in fopen ("rb" or "wb") but can also include a compression level
1051  ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
1052  Huffman only compression as in "wb1h", or 'R' for run-length encoding
1053  as in "wb1R". (See the description of deflateInit2 for more information
1054  about the strategy parameter.)
1055 
1056  gzopen can be used to read a file which is not in gzip format; in this
1057  case gzread will directly read from the file without decompression.
1058 
1059  gzopen returns NULL if the file could not be opened or if there was
1060  insufficient memory to allocate the (de)compression state; errno
1061  can be checked to distinguish the two cases (if errno is zero, the
1062  zlib error is Z_MEM_ERROR). */
1063 
1064 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1065 /*
1066  gzdopen() associates a gzFile with the file descriptor fd. File
1067  descriptors are obtained from calls like open, dup, creat, pipe or
1068  fileno (in the file has been previously opened with fopen).
1069  The mode parameter is as in gzopen.
1070  The next call of gzclose on the returned gzFile will also close the
1071  file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
1072  descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
1073  gzdopen returns NULL if there was insufficient memory to allocate
1074  the (de)compression state.
1075 */
1076 
1077 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1078 /*
1079  Dynamically update the compression level or strategy. See the description
1080  of deflateInit2 for the meaning of these parameters.
1081  gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1082  opened for writing.
1083 */
1084 
1085 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1086 /*
1087  Reads the given number of uncompressed bytes from the compressed file.
1088  If the input file was not in gzip format, gzread copies the given number
1089  of bytes into the buffer.
1090  gzread returns the number of uncompressed bytes actually read (0 for
1091  end of file, -1 for error). */
1092 
1093 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1094  voidpc buf, unsigned len));
1095 /*
1096  Writes the given number of uncompressed bytes into the compressed file.
1097  gzwrite returns the number of uncompressed bytes actually written
1098  (0 in case of error).
1099 */
1100 
1101 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
1102 /*
1103  Converts, formats, and writes the args to the compressed file under
1104  control of the format string, as in fprintf. gzprintf returns the number of
1105  uncompressed bytes actually written (0 in case of error). The number of
1106  uncompressed bytes written is limited to 4095. The caller should assure that
1107  this limit is not exceeded. If it is exceeded, then gzprintf() will return
1108  return an error (0) with nothing written. In this case, there may also be a
1109  buffer overflow with unpredictable consequences, which is possible only if
1110  zlib was compiled with the insecure functions sprintf() or vsprintf()
1111  because the secure snprintf() or vsnprintf() functions were not available.
1112 */
1113 
1114 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1115 /*
1116  Writes the given null-terminated string to the compressed file, excluding
1117  the terminating null character.
1118  gzputs returns the number of characters written, or -1 in case of error.
1119 */
1120 
1121 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1122 /*
1123  Reads bytes from the compressed file until len-1 characters are read, or
1124  a newline character is read and transferred to buf, or an end-of-file
1125  condition is encountered. The string is then terminated with a null
1126  character.
1127  gzgets returns buf, or Z_NULL in case of error.
1128 */
1129 
1130 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1131 /*
1132  Writes c, converted to an unsigned char, into the compressed file.
1133  gzputc returns the value that was written, or -1 in case of error.
1134 */
1135 
1136 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1137 /*
1138  Reads one byte from the compressed file. gzgetc returns this byte
1139  or -1 in case of end of file or error.
1140 */
1141 
1142 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1143 /*
1144  Push one character back onto the stream to be read again later.
1145  Only one character of push-back is allowed. gzungetc() returns the
1146  character pushed, or -1 on failure. gzungetc() will fail if a
1147  character has been pushed but not read yet, or if c is -1. The pushed
1148  character will be discarded if the stream is repositioned with gzseek()
1149  or gzrewind().
1150 */
1151 
1152 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1153 /*
1154  Flushes all pending output into the compressed file. The parameter
1155  flush is as in the deflate() function. The return value is the zlib
1156  error number (see function gzerror below). gzflush returns Z_OK if
1157  the flush parameter is Z_FINISH and all output could be flushed.
1158  gzflush should be called only when strictly necessary because it can
1159  degrade compression.
1160 */
1161 
1162 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1163  z_off_t offset, int whence));
1164 /*
1165  Sets the starting position for the next gzread or gzwrite on the
1166  given compressed file. The offset represents a number of bytes in the
1167  uncompressed data stream. The whence parameter is defined as in lseek(2);
1168  the value SEEK_END is not supported.
1169  If the file is opened for reading, this function is emulated but can be
1170  extremely slow. If the file is opened for writing, only forward seeks are
1171  supported; gzseek then compresses a sequence of zeroes up to the new
1172  starting position.
1173 
1174  gzseek returns the resulting offset location as measured in bytes from
1175  the beginning of the uncompressed stream, or -1 in case of error, in
1176  particular if the file is opened for writing and the new starting position
1177  would be before the current position.
1178 */
1179 
1180 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1181 /*
1182  Rewinds the given file. This function is supported only for reading.
1183 
1184  gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1185 */
1186 
1187 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1188 /*
1189  Returns the starting position for the next gzread or gzwrite on the
1190  given compressed file. This position represents a number of bytes in the
1191  uncompressed data stream.
1192 
1193  gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1194 */
1195 
1196 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1197 /*
1198  Returns 1 when EOF has previously been detected reading the given
1199  input stream, otherwise zero.
1200 */
1201 
1202 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1203 /*
1204  Returns 1 if file is being read directly without decompression, otherwise
1205  zero.
1206 */
1207 
1208 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1209 /*
1210  Flushes all pending output if necessary, closes the compressed file
1211  and deallocates all the (de)compression state. The return value is the zlib
1212  error number (see function gzerror below).
1213 */
1214 
1215 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1216 /*
1217  Returns the error message for the last error which occurred on the
1218  given compressed file. errnum is set to zlib error number. If an
1219  error occurred in the file system and not in the compression library,
1220  errnum is set to Z_ERRNO and the application may consult errno
1221  to get the exact error code.
1222 */
1223 
1224 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1225 /*
1226  Clears the error and end-of-file flags for file. This is analogous to the
1227  clearerr() function in stdio. This is useful for continuing to read a gzip
1228  file that is being written concurrently.
1229 */
1230 
1231  /* checksum functions */
1232 
1233 /*
1234  These functions are not related to compression but are exported
1235  anyway because they might be useful in applications using the
1236  compression library.
1237 */
1238 
1239 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1240 /*
1241  Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1242  return the updated checksum. If buf is NULL, this function returns
1243  the required initial value for the checksum.
1244  An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1245  much faster. Usage example:
1246 
1247  uLong adler = adler32(0L, Z_NULL, 0);
1248 
1249  while (read_buffer(buffer, length) != EOF) {
1250  adler = adler32(adler, buffer, length);
1251  }
1252  if (adler != original_adler) error();
1253 */
1254 
1255 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1256  z_off_t len2));
1257 /*
1258  Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1259  and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1260  each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1261  seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
1262 */
1263 
1264 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1265 /*
1266  Update a running CRC-32 with the bytes buf[0..len-1] and return the
1267  updated CRC-32. If buf is NULL, this function returns the required initial
1268  value for the for the crc. Pre- and post-conditioning (one's complement) is
1269  performed within this function so it shouldn't be done by the application.
1270  Usage example:
1271 
1272  uLong crc = crc32(0L, Z_NULL, 0);
1273 
1274  while (read_buffer(buffer, length) != EOF) {
1275  crc = crc32(crc, buffer, length);
1276  }
1277  if (crc != original_crc) error();
1278 */
1279 
1280 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1281 
1282 /*
1283  Combine two CRC-32 check values into one. For two sequences of bytes,
1284  seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1285  calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1286  check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1287  len2.
1288 */
1289 
1290 
1291  /* various hacks, don't look :) */
1292 
1293 /* deflateInit and inflateInit are macros to allow checking the zlib version
1294  * and the compiler's view of z_stream:
1295  */
1296 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1297  const char *version, int stream_size));
1298 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1299  const char *version, int stream_size));
1300 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1301  int windowBits, int memLevel,
1302  int strategy, const char *version,
1303  int stream_size));
1304 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1305  const char *version, int stream_size));
1306 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1307  unsigned char FAR *window,
1308  const char *version,
1309  int stream_size));
1310 #define deflateInit(strm, level) \
1311  deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
1312 #define inflateInit(strm) \
1313  inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
1314 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1315  deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1316  (strategy), ZLIB_VERSION, sizeof(z_stream))
1317 #define inflateInit2(strm, windowBits) \
1318  inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
1319 #define inflateBackInit(strm, windowBits, window) \
1320  inflateBackInit_((strm), (windowBits), (window), \
1321  ZLIB_VERSION, sizeof(z_stream))
1322 
1323 
1324 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1325  struct internal_state {int dummy;}; /* hack for buggy compilers */
1326 #endif
1327 
1328 ZEXTERN const char * ZEXPORT zError OF((int));
1329 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
1330 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
1331 
1332 #ifdef __cplusplus
1333 }
1334 #endif
1335 
1336 #endif /* ZLIB_H */
int xflags
Definition: zlib.h:91
Bytef * extra
Definition: zlib.h:93
GLdouble GLdouble z
Definition: glext.h:3734
int text
Definition: zlib.h:89
Bytef * next_in
Definition: zlib.h:62
voidpf alloc_func OF((voidpf opaque, uInt items, uInt size))
Definition: zlib.h:56
int hcrc
Definition: zlib.h:100
uLong time
Definition: zlib.h:90
#define z_off_t
Definition: zconf.h:305
uInt avail_in
Definition: zlib.h:63
GLintptr offset
Definition: glext.h:3780
Bytef * name
Definition: zlib.h:96
uInt extra_max
Definition: zlib.h:95
char * msg
Definition: zlib.h:70
uInt name_max
Definition: zlib.h:97
int done
Definition: zlib.h:101
unsigned long uLong
Definition: zconf.h:268
struct gz_header_s gz_header
gz_header FAR * gz_headerp
Definition: zlib.h:105
GLdouble s
Definition: glext.h:3602
GLenum GLsizei len
Definition: glext.h:4349
Byte FAR Bytef
Definition: zconf.h:274
voidpf opaque
Definition: zlib.h:75
struct internal_state FAR * state
Definition: zlib.h:71
voidp gzFile
Definition: zlib.h:1045
free_func zfree
Definition: zlib.h:74
void * voidp
Definition: zconf.h:284
uLong reserved
Definition: zlib.h:79
uInt extra_len
Definition: zlib.h:94
const GLubyte * c
Definition: glext.h:5590
int data_type
Definition: zlib.h:77
int os
Definition: zlib.h:92
uLong total_in
Definition: zlib.h:64
int version
Definition: mrpt_jpeglib.h:898
alloc_func zalloc
Definition: zlib.h:73
Bytef * next_out
Definition: zlib.h:66
GLint mode
Definition: glext.h:5078
Bytef * comment
Definition: zlib.h:98
uLong adler
Definition: zlib.h:78
uLong total_out
Definition: zlib.h:68
void const * voidpc
Definition: zconf.h:282
#define ZEXTERN
Definition: zconf.h:251
uLong FAR uLongf
Definition: zconf.h:279
GLuint in
Definition: glext.h:6301
GLint level
Definition: glext.h:3545
GLsizei GLsizei GLchar * source
Definition: glext.h:3908
uInt comm_max
Definition: zlib.h:99
GLuint address
Definition: glext.h:6078
uInt avail_out
Definition: zlib.h:67
typedef void(APIENTRYP PFNGLBLENDCOLORPROC)(GLclampf red
GLenum GLsizei GLenum format
Definition: glext.h:3513
GLsizei const GLfloat * value
Definition: glext.h:3929
void BASE_IMPEXP 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:3779
struct z_stream_s z_stream
#define FAR
Definition: zconf.h:261
z_stream FAR * z_streamp
Definition: zlib.h:82
void FAR * voidpf
Definition: zconf.h:283
#define ZEXPORT
Definition: zconf.h:254
#define ZEXPORTVA
Definition: zconf.h:257
unsigned int uInt
Definition: zconf.h:267



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