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 http://www.ietf.org/rfc/rfc1950.txt
27 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
28 */
29
30 #ifndef _ZLIB_H
31 #define _ZLIB_H
32
33 #include <linux/zconf.h>
34
35 /* zlib deflate based on ZLIB_VERSION "1.1.3" */
36 /* zlib inflate based on ZLIB_VERSION "1.2.3" */
37
38 /*
39 This is a modified version of zlib for use inside the Linux kernel.
40 The main changes are to perform all memory allocation in advance.
41
42 Inflation Changes:
43 * Z_PACKET_FLUSH is added and used by ppp_deflate. Before returning
44 this checks there is no more input data available and the next data
45 is a STORED block. It also resets the mode to be read for the next
46 data, all as per PPP requirements.
47 * Addition of zlib_inflateIncomp which copies incompressible data into
48 the history window and adjusts the accoutning without calling
49 zlib_inflate itself to inflate the data.
50 */
51
52 /*
53 The 'zlib' compression library provides in-memory compression and
54 decompression functions, including integrity checks of the uncompressed
55 data. This version of the library supports only one compression method
56 (deflation) but other algorithms will be added later and will have the same
57 stream interface.
58
59 Compression can be done in a single step if the buffers are large
60 enough (for example if an input file is mmap'ed), or can be done by
61 repeated calls of the compression function. In the latter case, the
62 application must provide more input and/or consume the output
63 (providing more output space) before each call.
64
65 The compressed data format used by default by the in-memory functions is
66 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
67 around a deflate stream, which is itself documented in RFC 1951.
68
69 The library also supports reading and writing files in gzip (.gz) format
70 with an interface similar to that of stdio.
71
72 The zlib format was designed to be compact and fast for use in memory
73 and on communications channels. The gzip format was designed for single-
74 file compression on file systems, has a larger header than zlib to maintain
75 directory information, and uses a different, slower check method than zlib.
76
77 The library does not install any signal handler. The decoder checks
78 the consistency of the compressed data, so the library should never
79 crash even in case of corrupted input.
80 */
81
82 struct internal_state;
83
84 typedef struct z_stream_s {
85 const Byte *next_in; /* next input byte */
86 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 /*
195 extern int deflateInit (z_streamp strm, int level);
196
197 Initializes the internal stream state for compression. The fields
198 zalloc, zfree and opaque must be initialized before by the caller.
199 If zalloc and zfree are set to NULL, deflateInit updates them to
200 use default allocation functions.
201
202 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
203 1 gives best speed, 9 gives best compression, 0 gives no compression at
204 all (the input data is simply copied a block at a time).
205 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
206 compression (currently equivalent to level 6).
207
208 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
209 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
210 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
211 with the version assumed by the caller (ZLIB_VERSION).
212 msg is set to null if there is no error message. deflateInit does not
213 perform any compression: this will be done by deflate().
214 */
215
216
217 extern int zlib_deflate (z_streamp strm, int flush);
218 /*
219 deflate compresses as much data as possible, and stops when the input
220 buffer becomes empty or the output buffer becomes full. It may introduce some
221 output latency (reading input without producing any output) except when
222 forced to flush.
223
224 The detailed semantics are as follows. deflate performs one or both of the
225 following actions:
226
227 - Compress more input starting at next_in and update next_in and avail_in
228 accordingly. If not all input can be processed (because there is not
229 enough room in the output buffer), next_in and avail_in are updated and
230 processing will resume at this point for the next call of deflate().
231
232 - Provide more output starting at next_out and update next_out and avail_out
233 accordingly. This action is forced if the parameter flush is non zero.
234 Forcing flush frequently degrades the compression ratio, so this parameter
235 should be set only when necessary (in interactive applications).
236 Some output may be provided even if flush is not set.
237
238 Before the call of deflate(), the application should ensure that at least
239 one of the actions is possible, by providing more input and/or consuming
240 more output, and updating avail_in or avail_out accordingly; avail_out
241 should never be zero before the call. The application can consume the
242 compressed output when it wants, for example when the output buffer is full
243 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
244 and with zero avail_out, it must be called again after making room in the
245 output buffer because there might be more output pending.
246
247 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
248 flushed to the output buffer and the output is aligned on a byte boundary, so
249 that the decompressor can get all input data available so far. (In particular
250 avail_in is zero after the call if enough output space has been provided
251 before the call.) Flushing may degrade compression for some compression
252 algorithms and so it should be used only when necessary.
253
254 If flush is set to Z_FULL_FLUSH, all output is flushed as with
255 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
256 restart from this point if previous compressed data has been damaged or if
257 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
258 the compression.
259
260 If deflate returns with avail_out == 0, this function must be called again
261 with the same value of the flush parameter and more output space (updated
262 avail_out), until the flush is complete (deflate returns with non-zero
263 avail_out).
264
265 If the parameter flush is set to Z_FINISH, pending input is processed,
266 pending output is flushed and deflate returns with Z_STREAM_END if there
267 was enough output space; if deflate returns with Z_OK, this function must be
268 called again with Z_FINISH and more output space (updated avail_out) but no
269 more input data, until it returns with Z_STREAM_END or an error. After
270 deflate has returned Z_STREAM_END, the only possible operations on the
271 stream are deflateReset or deflateEnd.
272
273 Z_FINISH can be used immediately after deflateInit if all the compression
274 is to be done in a single step. In this case, avail_out must be at least
275 0.1% larger than avail_in plus 12 bytes. If deflate does not return
276 Z_STREAM_END, then it must be called again as described above.
277
278 deflate() sets strm->adler to the adler32 checksum of all input read
279 so far (that is, total_in bytes).
280
281 deflate() may update data_type if it can make a good guess about
282 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
283 binary. This field is only for information purposes and does not affect
284 the compression algorithm in any manner.
285
286 deflate() returns Z_OK if some progress has been made (more input
287 processed or more output produced), Z_STREAM_END if all input has been
288 consumed and all output has been produced (only when flush is set to
289 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
290 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
291 (for example avail_in or avail_out was zero).
292 */
293
294
295 extern int zlib_deflateEnd (z_streamp strm);
296 /*
297 All dynamically allocated data structures for this stream are freed.
298 This function discards any unprocessed input and does not flush any
299 pending output.
300
301 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
302 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
303 prematurely (some input or output was discarded). In the error case,
304 msg may be set but then points to a static string (which must not be
305 deallocated).
306 */
307
308
309 extern int zlib_inflate_workspacesize (void);
310 /*
311 Returns the number of bytes that needs to be allocated for a per-
312 stream workspace. A pointer to this number of bytes should be
313 returned in stream->workspace before calling zlib_inflateInit().
314 */
315
316 /*
317 extern int zlib_inflateInit (z_streamp strm);
318
319 Initializes the internal stream state for decompression. The fields
320 next_in, avail_in, and workspace must be initialized before by
321 the caller. If next_in is not NULL and avail_in is large enough (the exact
322 value depends on the compression method), inflateInit determines the
323 compression method from the zlib header and allocates all data structures
324 accordingly; otherwise the allocation will be deferred to the first call of
325 inflate. If zalloc and zfree are set to NULL, inflateInit updates them to
326 use default allocation functions.
327
328 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
329 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
330 version assumed by the caller. msg is set to null if there is no error
331 message. inflateInit does not perform any decompression apart from reading
332 the zlib header if present: this will be done by inflate(). (So next_in and
333 avail_in may be modified, but next_out and avail_out are unchanged.)
334 */
335
336
337 extern int zlib_inflate (z_streamp strm, int flush);
338 /*
339 inflate decompresses as much data as possible, and stops when the input
340 buffer becomes empty or the output buffer becomes full. It may introduce
341 some output latency (reading input without producing any output) except when
342 forced to flush.
343
344 The detailed semantics are as follows. inflate performs one or both of the
345 following actions:
346
347 - Decompress more input starting at next_in and update next_in and avail_in
348 accordingly. If not all input can be processed (because there is not
349 enough room in the output buffer), next_in is updated and processing
350 will resume at this point for the next call of inflate().
351
352 - Provide more output starting at next_out and update next_out and avail_out
353 accordingly. inflate() provides as much output as possible, until there
354 is no more input data or no more space in the output buffer (see below
355 about the flush parameter).
356
357 Before the call of inflate(), the application should ensure that at least
358 one of the actions is possible, by providing more input and/or consuming
359 more output, and updating the next_* and avail_* values accordingly.
360 The application can consume the uncompressed output when it wants, for
361 example when the output buffer is full (avail_out == 0), or after each
362 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
363 must be called again after making room in the output buffer because there
364 might be more output pending.
365
366 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
367 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
368 output as possible to the output buffer. Z_BLOCK requests that inflate() stop
369 if and when it gets to the next deflate block boundary. When decoding the
370 zlib or gzip format, this will cause inflate() to return immediately after
371 the header and before the first block. When doing a raw inflate, inflate()
372 will go ahead and process the first block, and will return when it gets to
373 the end of that block, or when it runs out of data.
374
375 The Z_BLOCK option assists in appending to or combining deflate streams.
376 Also to assist in this, on return inflate() will set strm->data_type to the
377 number of unused bits in the last byte taken from strm->next_in, plus 64
378 if inflate() is currently decoding the last block in the deflate stream,
379 plus 128 if inflate() returned immediately after decoding an end-of-block
380 code or decoding the complete header up to just before the first byte of the
381 deflate stream. The end-of-block will not be indicated until all of the
382 uncompressed data from that block has been written to strm->next_out. The
383 number of unused bits may in general be greater than seven, except when
384 bit 7 of data_type is set, in which case the number of unused bits will be
385 less than eight.
386
387 inflate() should normally be called until it returns Z_STREAM_END or an
388 error. However if all decompression is to be performed in a single step
389 (a single call of inflate), the parameter flush should be set to
390 Z_FINISH. In this case all pending input is processed and all pending
391 output is flushed; avail_out must be large enough to hold all the
392 uncompressed data. (The size of the uncompressed data may have been saved
393 by the compressor for this purpose.) The next operation on this stream must
394 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
395 is never required, but can be used to inform inflate that a faster approach
396 may be used for the single inflate() call.
397
398 In this implementation, inflate() always flushes as much output as
399 possible to the output buffer, and always uses the faster approach on the
400 first call. So the only effect of the flush parameter in this implementation
401 is on the return value of inflate(), as noted below, or when it returns early
402 because Z_BLOCK is used.
403
404 If a preset dictionary is needed after this call (see inflateSetDictionary
405 below), inflate sets strm->adler to the adler32 checksum of the dictionary
406 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
407 strm->adler to the adler32 checksum of all output produced so far (that is,
408 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
409 below. At the end of the stream, inflate() checks that its computed adler32
410 checksum is equal to that saved by the compressor and returns Z_STREAM_END
411 only if the checksum is correct.
412
413 inflate() will decompress and check either zlib-wrapped or gzip-wrapped
414 deflate data. The header type is detected automatically. Any information
415 contained in the gzip header is not retained, so applications that need that
416 information should instead use raw inflate, see inflateInit2() below, or
417 inflateBack() and perform their own processing of the gzip header and
418 trailer.
419
420 inflate() returns Z_OK if some progress has been made (more input processed
421 or more output produced), Z_STREAM_END if the end of the compressed data has
422 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
423 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
424 corrupted (input stream not conforming to the zlib format or incorrect check
425 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
426 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
427 Z_BUF_ERROR if no progress is possible or if there was not enough room in the
428 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
429 inflate() can be called again with more input and more output space to
430 continue decompressing. If Z_DATA_ERROR is returned, the application may then
431 call inflateSync() to look for a good compression block if a partial recovery
432 of the data is desired.
433 */
434
435
436 extern int zlib_inflateEnd (z_streamp strm);
437 /*
438 All dynamically allocated data structures for this stream are freed.
439 This function discards any unprocessed input and does not flush any
440 pending output.
441
442 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
443 was inconsistent. In the error case, msg may be set but then points to a
444 static string (which must not be deallocated).
445 */
446
447 /* Advanced functions */
448
449 /*
450 The following functions are needed only in some special applications.
451 */
452
453 /*
454 extern int deflateInit2 (z_streamp strm,
455 int level,
456 int method,
457 int windowBits,
458 int memLevel,
459 int strategy);
460
461 This is another version of deflateInit with more compression options. The
462 fields next_in, zalloc, zfree and opaque must be initialized before by
463 the caller.
464
465 The method parameter is the compression method. It must be Z_DEFLATED in
466 this version of the library.
467
468 The windowBits parameter is the base two logarithm of the window size
469 (the size of the history buffer). It should be in the range 8..15 for this
470 version of the library. Larger values of this parameter result in better
471 compression at the expense of memory usage. The default value is 15 if
472 deflateInit is used instead.
473
474 The memLevel parameter specifies how much memory should be allocated
475 for the internal compression state. memLevel=1 uses minimum memory but
476 is slow and reduces compression ratio; memLevel=9 uses maximum memory
477 for optimal speed. The default value is 8. See zconf.h for total memory
478 usage as a function of windowBits and memLevel.
479
480 The strategy parameter is used to tune the compression algorithm. Use the
481 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
482 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
483 string match). Filtered data consists mostly of small values with a
484 somewhat random distribution. In this case, the compression algorithm is
485 tuned to compress them better. The effect of Z_FILTERED is to force more
486 Huffman coding and less string matching; it is somewhat intermediate
487 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
488 the compression ratio but not the correctness of the compressed output even
489 if it is not set appropriately.
490
491 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
492 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
493 method). msg is set to null if there is no error message. deflateInit2 does
494 not perform any compression: this will be done by deflate().
495 */
496
497 extern int zlib_deflateReset (z_streamp strm);
498 /*
499 This function is equivalent to deflateEnd followed by deflateInit,
500 but does not free and reallocate all the internal compression state.
501 The stream will keep the same compression level and any other attributes
502 that may have been set by deflateInit2.
503
504 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
505 stream state was inconsistent (such as zalloc or state being NULL).
506 */
507
508 static inline unsigned long deflateBound(unsigned long s)
509 {
510 return s + ((s + 7) >> 3) + ((s + 63) >> 6) + 11;
511 }
512
513 /*
514 extern int inflateInit2 (z_streamp strm, int windowBits);
515
516 This is another version of inflateInit with an extra parameter. The
517 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
518 before by the caller.
519
520 The windowBits parameter is the base two logarithm of the maximum window
521 size (the size of the history buffer). It should be in the range 8..15 for
522 this version of the library. The default value is 15 if inflateInit is used
523 instead. windowBits must be greater than or equal to the windowBits value
524 provided to deflateInit2() while compressing, or it must be equal to 15 if
525 deflateInit2() was not used. If a compressed stream with a larger window
526 size is given as input, inflate() will return with the error code
527 Z_DATA_ERROR instead of trying to allocate a larger window.
528
529 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
530 determines the window size. inflate() will then process raw deflate data,
531 not looking for a zlib or gzip header, not generating a check value, and not
532 looking for any check values for comparison at the end of the stream. This
533 is for use with other formats that use the deflate compressed data format
534 such as zip. Those formats provide their own check values. If a custom
535 format is developed using the raw deflate format for compressed data, it is
536 recommended that a check value such as an adler32 or a crc32 be applied to
537 the uncompressed data as is done in the zlib, gzip, and zip formats. For
538 most applications, the zlib format should be used as is. Note that comments
539 above on the use in deflateInit2() applies to the magnitude of windowBits.
540
541 windowBits can also be greater than 15 for optional gzip decoding. Add
542 32 to windowBits to enable zlib and gzip decoding with automatic header
543 detection, or add 16 to decode only the gzip format (the zlib format will
544 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
545 a crc32 instead of an adler32.
546
547 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
548 memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
549 is set to null if there is no error message. inflateInit2 does not perform
550 any decompression apart from reading the zlib header if present: this will
551 be done by inflate(). (So next_in and avail_in may be modified, but next_out
552 and avail_out are unchanged.)
553 */
554
555 extern int zlib_inflateReset (z_streamp strm);
556 /*
557 This function is equivalent to inflateEnd followed by inflateInit,
558 but does not free and reallocate all the internal decompression state.
559 The stream will keep attributes that may have been set by inflateInit2.
560
561 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
562 stream state was inconsistent (such as zalloc or state being NULL).
563 */
564
565 extern int zlib_inflateIncomp (z_stream *strm);
566 /*
567 This function adds the data at next_in (avail_in bytes) to the output
568 history without performing any output. There must be no pending output,
569 and the decompressor must be expecting to see the start of a block.
570 Calling this function is equivalent to decompressing a stored block
571 containing the data at next_in (except that the data is not output).
572 */
573
574 #define zlib_deflateInit(strm, level) \
575 zlib_deflateInit2((strm), (level), Z_DEFLATED, MAX_WBITS, \
576 DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY)
577 #define zlib_inflateInit(strm) \
578 zlib_inflateInit2((strm), DEF_WBITS)
579
580 extern int zlib_deflateInit2(z_streamp strm, int level, int method,
581 int windowBits, int memLevel,
582 int strategy);
583 extern int zlib_inflateInit2(z_streamp strm, int windowBits);
584
585 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
586 struct internal_state {int dummy;}; /* hack for buggy compilers */
587 #endif
588
589 /* Utility function: initialize zlib, unpack binary blob, clean up zlib,
590 * return len or negative error code. */
591 extern int zlib_inflate_blob(void *dst, unsigned dst_sz, const void *src, unsigned src_sz);
592
593 #endif /* _ZLIB_H */