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