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1 /* $NetBSD: zlib.h,v 1.3 2009/03/25 18:41:06 tls Exp $ */
3 /* zlib.h -- interface of the 'zlib' general purpose compression library
4 version 1.2.3, July 18th, 2005
6 Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
8 This software is provided 'as-is', without any express or implied
9 warranty. In no event will the authors be held liable for any damages
10 arising from the use of this software.
12 Permission is granted to anyone to use this software for any purpose,
13 including commercial applications, and to alter it and redistribute it
14 freely, subject to the following restrictions:
16 1. The origin of this software must not be misrepresented; you must not
17 claim that you wrote the original software. If you use this software
18 in a product, an acknowledgment in the product documentation would be
19 appreciated but is not required.
20 2. Altered source versions must be plainly marked as such, and must not be
21 misrepresented as being the original software.
22 3. This notice may not be removed or altered from any source distribution.
24 Jean-loup Gailly Mark Adler
25 jloup@gzip.org madler@alumni.caltech.edu
28 The data format used by the zlib library is described by RFCs (Request for
29 Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
30 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
31 */
33 #ifndef ZLIB_H
34 #define ZLIB_H
38 #ifdef __cplusplus
40 #endif
43 #define ZLIB_VERNUM 0x1230
45 /*
46 The 'zlib' compression library provides in-memory compression and
47 decompression functions, including integrity checks of the uncompressed
48 data. This version of the library supports only one compression method
49 (deflation) but other algorithms will be added later and will have the same
50 stream interface.
52 Compression can be done in a single step if the buffers are large
53 enough (for example if an input file is mmap'ed), or can be done by
54 repeated calls of the compression function. In the latter case, the
55 application must provide more input and/or consume the output
56 (providing more output space) before each call.
58 The compressed data format used by default by the in-memory functions is
59 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
60 around a deflate stream, which is itself documented in RFC 1951.
62 The library also supports reading and writing files in gzip (.gz) format
63 with an interface similar to that of stdio using the functions that start
64 with "gz". The gzip format is different from the zlib format. gzip is a
65 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
67 This library can optionally read and write gzip streams in memory as well.
69 The zlib format was designed to be compact and fast for use in memory
70 and on communications channels. The gzip format was designed for single-
71 file compression on file systems, has a larger header than zlib to maintain
72 directory information, and uses a different, slower check method than zlib.
74 The library does not install any signal handler. The decoder checks
75 the consistency of the compressed data, so the library should never
76 crash even in case of corrupted input.
77 */
107 /*
108 gzip header information passed to and from zlib routines. See RFC 1952
109 for more details on the meanings of these fields.
110 */
125 when writing a gzip file) */
130 /*
131 The application must update next_in and avail_in when avail_in has
132 dropped to zero. It must update next_out and avail_out when avail_out
133 has dropped to zero. The application must initialize zalloc, zfree and
134 opaque before calling the init function. All other fields are set by the
135 compression library and must not be updated by the application.
137 The opaque value provided by the application will be passed as the first
138 parameter for calls of zalloc and zfree. This can be useful for custom
139 memory management. The compression library attaches no meaning to the
140 opaque value.
142 zalloc must return Z_NULL if there is not enough memory for the object.
143 If zlib is used in a multi-threaded application, zalloc and zfree must be
144 thread safe.
146 On 16-bit systems, the functions zalloc and zfree must be able to allocate
147 exactly 65536 bytes, but will not be required to allocate more than this
148 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
149 pointers returned by zalloc for objects of exactly 65536 bytes *must*
150 have their offset normalized to zero. The default allocation function
151 provided by this library ensures this (see zutil.c). To reduce memory
152 requirements and avoid any allocation of 64K objects, at the expense of
153 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
155 The fields total_in and total_out can be used for statistics or
156 progress reports. After compression, total_in holds the total size of
157 the uncompressed data and may be saved for use in the decompressor
158 (particularly if the decompressor wants to decompress everything in
159 a single step).
160 */
162 /* constants */
164 #define Z_NO_FLUSH 0
166 #define Z_SYNC_FLUSH 2
167 #define Z_FULL_FLUSH 3
168 #define Z_FINISH 4
169 #define Z_BLOCK 5
170 /* Allowed flush values; see deflate() and inflate() below for details */
172 #define Z_OK 0
173 #define Z_STREAM_END 1
174 #define Z_NEED_DICT 2
175 #define Z_ERRNO (-1)
176 #define Z_STREAM_ERROR (-2)
177 #define Z_DATA_ERROR (-3)
178 #define Z_MEM_ERROR (-4)
179 #define Z_BUF_ERROR (-5)
180 #define Z_VERSION_ERROR (-6)
181 /* Return codes for the compression/decompression functions. Negative
182 * values are errors, positive values are used for special but normal events.
183 */
185 #define Z_NO_COMPRESSION 0
186 #define Z_BEST_SPEED 1
187 #define Z_BEST_COMPRESSION 9
188 #define Z_DEFAULT_COMPRESSION (-1)
189 /* compression levels */
191 #define Z_FILTERED 1
192 #define Z_HUFFMAN_ONLY 2
193 #define Z_RLE 3
194 #define Z_FIXED 4
195 #define Z_DEFAULT_STRATEGY 0
196 /* compression strategy; see deflateInit2() below for details */
198 #define Z_BINARY 0
199 #define Z_TEXT 1
201 #define Z_UNKNOWN 2
202 /* Possible values of the data_type field (though see inflate()) */
204 #define Z_DEFLATED 8
205 /* The deflate compression method (the only one supported in this version) */
209 #define zlib_version zlibVersion()
210 /* for compatibility with versions < 1.0.2 */
212 /* basic functions */
215 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
216 If the first character differs, the library code actually used is
217 not compatible with the zlib.h header file used by the application.
218 This check is automatically made by deflateInit and inflateInit.
219 */
221 /*
222 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
224 Initializes the internal stream state for compression. The fields
225 zalloc, zfree and opaque must be initialized before by the caller.
226 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
227 use default allocation functions.
229 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
230 1 gives best speed, 9 gives best compression, 0 gives no compression at
231 all (the input data is simply copied a block at a time).
232 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
233 compression (currently equivalent to level 6).
235 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
236 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
237 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
238 with the version assumed by the caller (ZLIB_VERSION).
239 msg is set to null if there is no error message. deflateInit does not
240 perform any compression: this will be done by deflate().
241 */
245 /*
246 deflate compresses as much data as possible, and stops when the input
247 buffer becomes empty or the output buffer becomes full. It may introduce some
248 output latency (reading input without producing any output) except when
249 forced to flush.
251 The detailed semantics are as follows. deflate performs one or both of the
252 following actions:
254 - Compress more input starting at next_in and update next_in and avail_in
255 accordingly. If not all input can be processed (because there is not
256 enough room in the output buffer), next_in and avail_in are updated and
257 processing will resume at this point for the next call of deflate().
259 - Provide more output starting at next_out and update next_out and avail_out
260 accordingly. This action is forced if the parameter flush is non zero.
261 Forcing flush frequently degrades the compression ratio, so this parameter
262 should be set only when necessary (in interactive applications).
263 Some output may be provided even if flush is not set.
265 Before the call of deflate(), the application should ensure that at least
266 one of the actions is possible, by providing more input and/or consuming
267 more output, and updating avail_in or avail_out accordingly; avail_out
268 should never be zero before the call. The application can consume the
269 compressed output when it wants, for example when the output buffer is full
270 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
271 and with zero avail_out, it must be called again after making room in the
272 output buffer because there might be more output pending.
274 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
275 decide how much data to accumualte before producing output, in order to
276 maximize compression.
278 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
279 flushed to the output buffer and the output is aligned on a byte boundary, so
280 that the decompressor can get all input data available so far. (In particular
281 avail_in is zero after the call if enough output space has been provided
282 before the call.) Flushing may degrade compression for some compression
283 algorithms and so it should be used only when necessary.
285 If flush is set to Z_FULL_FLUSH, all output is flushed as with
286 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
287 restart from this point if previous compressed data has been damaged or if
288 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
289 compression.
291 If deflate returns with avail_out == 0, this function must be called again
292 with the same value of the flush parameter and more output space (updated
293 avail_out), until the flush is complete (deflate returns with non-zero
294 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
295 avail_out is greater than six to avoid repeated flush markers due to
296 avail_out == 0 on return.
298 If the parameter flush is set to Z_FINISH, pending input is processed,
299 pending output is flushed and deflate returns with Z_STREAM_END if there
300 was enough output space; if deflate returns with Z_OK, this function must be
301 called again with Z_FINISH and more output space (updated avail_out) but no
302 more input data, until it returns with Z_STREAM_END or an error. After
303 deflate has returned Z_STREAM_END, the only possible operations on the
304 stream are deflateReset or deflateEnd.
306 Z_FINISH can be used immediately after deflateInit if all the compression
307 is to be done in a single step. In this case, avail_out must be at least
308 the value returned by deflateBound (see below). If deflate does not return
309 Z_STREAM_END, then it must be called again as described above.
311 deflate() sets strm->adler to the adler32 checksum of all input read
312 so far (that is, total_in bytes).
314 deflate() may update strm->data_type if it can make a good guess about
315 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
316 binary. This field is only for information purposes and does not affect
317 the compression algorithm in any manner.
319 deflate() returns Z_OK if some progress has been made (more input
320 processed or more output produced), Z_STREAM_END if all input has been
321 consumed and all output has been produced (only when flush is set to
322 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
323 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
324 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
325 fatal, and deflate() can be called again with more input and more output
326 space to continue compressing.
327 */
331 /*
332 All dynamically allocated data structures for this stream are freed.
333 This function discards any unprocessed input and does not flush any
334 pending output.
336 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
337 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
338 prematurely (some input or output was discarded). In the error case,
339 msg may be set but then points to a static string (which must not be
340 deallocated).
341 */
344 /*
345 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
347 Initializes the internal stream state for decompression. The fields
348 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
349 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
350 value depends on the compression method), inflateInit determines the
351 compression method from the zlib header and allocates all data structures
352 accordingly; otherwise the allocation will be deferred to the first call of
353 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
354 use default allocation functions.
356 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
357 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
358 version assumed by the caller. msg is set to null if there is no error
359 message. inflateInit does not perform any decompression apart from reading
360 the zlib header if present: this will be done by inflate(). (So next_in and
361 avail_in may be modified, but next_out and avail_out are unchanged.)
362 */
366 /*
367 inflate decompresses as much data as possible, and stops when the input
368 buffer becomes empty or the output buffer becomes full. It may introduce
369 some output latency (reading input without producing any output) except when
370 forced to flush.
372 The detailed semantics are as follows. inflate performs one or both of the
373 following actions:
375 - Decompress more input starting at next_in and update next_in and avail_in
376 accordingly. If not all input can be processed (because there is not
377 enough room in the output buffer), next_in is updated and processing
378 will resume at this point for the next call of inflate().
380 - Provide more output starting at next_out and update next_out and avail_out
381 accordingly. inflate() provides as much output as possible, until there
382 is no more input data or no more space in the output buffer (see below
383 about the flush parameter).
385 Before the call of inflate(), the application should ensure that at least
386 one of the actions is possible, by providing more input and/or consuming
387 more output, and updating the next_* and avail_* values accordingly.
388 The application can consume the uncompressed output when it wants, for
389 example when the output buffer is full (avail_out == 0), or after each
390 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
391 must be called again after making room in the output buffer because there
392 might be more output pending.
394 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
395 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
396 output as possible to the output buffer. Z_BLOCK requests that inflate() stop
397 if and when it gets to the next deflate block boundary. When decoding the
398 zlib or gzip format, this will cause inflate() to return immediately after
399 the header and before the first block. When doing a raw inflate, inflate()
400 will go ahead and process the first block, and will return when it gets to
401 the end of that block, or when it runs out of data.
403 The Z_BLOCK option assists in appending to or combining deflate streams.
404 Also to assist in this, on return inflate() will set strm->data_type to the
405 number of unused bits in the last byte taken from strm->next_in, plus 64
406 if inflate() is currently decoding the last block in the deflate stream,
407 plus 128 if inflate() returned immediately after decoding an end-of-block
408 code or decoding the complete header up to just before the first byte of the
409 deflate stream. The end-of-block will not be indicated until all of the
410 uncompressed data from that block has been written to strm->next_out. The
411 number of unused bits may in general be greater than seven, except when
412 bit 7 of data_type is set, in which case the number of unused bits will be
413 less than eight.
415 inflate() should normally be called until it returns Z_STREAM_END or an
416 error. However if all decompression is to be performed in a single step
417 (a single call of inflate), the parameter flush should be set to
418 Z_FINISH. In this case all pending input is processed and all pending
419 output is flushed; avail_out must be large enough to hold all the
420 uncompressed data. (The size of the uncompressed data may have been saved
421 by the compressor for this purpose.) The next operation on this stream must
422 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
423 is never required, but can be used to inform inflate that a faster approach
424 may be used for the single inflate() call.
426 In this implementation, inflate() always flushes as much output as
427 possible to the output buffer, and always uses the faster approach on the
428 first call. So the only effect of the flush parameter in this implementation
429 is on the return value of inflate(), as noted below, or when it returns early
430 because Z_BLOCK is used.
432 If a preset dictionary is needed after this call (see inflateSetDictionary
433 below), inflate sets strm->adler to the adler32 checksum of the dictionary
434 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
435 strm->adler to the adler32 checksum of all output produced so far (that is,
436 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
437 below. At the end of the stream, inflate() checks that its computed adler32
438 checksum is equal to that saved by the compressor and returns Z_STREAM_END
439 only if the checksum is correct.
441 inflate() will decompress and check either zlib-wrapped or gzip-wrapped
442 deflate data. The header type is detected automatically. Any information
443 contained in the gzip header is not retained, so applications that need that
444 information should instead use raw inflate, see inflateInit2() below, or
445 inflateBack() and perform their own processing of the gzip header and
446 trailer.
448 inflate() returns Z_OK if some progress has been made (more input processed
449 or more output produced), Z_STREAM_END if the end of the compressed data has
450 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
451 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
452 corrupted (input stream not conforming to the zlib format or incorrect check
453 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
454 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
455 Z_BUF_ERROR if no progress is possible or if there was not enough room in the
456 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
457 inflate() can be called again with more input and more output space to
458 continue decompressing. If Z_DATA_ERROR is returned, the application may then
459 call inflateSync() to look for a good compression block if a partial recovery
460 of the data is desired.
461 */
465 /*
466 All dynamically allocated data structures for this stream are freed.
467 This function discards any unprocessed input and does not flush any
468 pending output.
470 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
471 was inconsistent. In the error case, msg may be set but then points to a
472 static string (which must not be deallocated).
473 */
475 /* Advanced functions */
477 /*
478 The following functions are needed only in some special applications.
479 */
481 /*
482 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
483 int level,
484 int method,
485 int windowBits,
486 int memLevel,
487 int strategy));
489 This is another version of deflateInit with more compression options. The
490 fields next_in, zalloc, zfree and opaque must be initialized before by
491 the caller.
493 The method parameter is the compression method. It must be Z_DEFLATED in
494 this version of the library.
496 The windowBits parameter is the base two logarithm of the window size
497 (the size of the history buffer). It should be in the range 8..15 for this
498 version of the library. Larger values of this parameter result in better
499 compression at the expense of memory usage. The default value is 15 if
500 deflateInit is used instead.
502 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
503 determines the window size. deflate() will then generate raw deflate data
504 with no zlib header or trailer, and will not compute an adler32 check value.
506 windowBits can also be greater than 15 for optional gzip encoding. Add
507 16 to windowBits to write a simple gzip header and trailer around the
508 compressed data instead of a zlib wrapper. The gzip header will have no
509 file name, no extra data, no comment, no modification time (set to zero),
510 no header crc, and the operating system will be set to 255 (unknown). If a
511 gzip stream is being written, strm->adler is a crc32 instead of an adler32.
513 The memLevel parameter specifies how much memory should be allocated
514 for the internal compression state. memLevel=1 uses minimum memory but
515 is slow and reduces compression ratio; memLevel=9 uses maximum memory
516 for optimal speed. The default value is 8. See zconf.h for total memory
517 usage as a function of windowBits and memLevel.
519 The strategy parameter is used to tune the compression algorithm. Use the
520 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
521 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
522 string match), or Z_RLE to limit match distances to one (run-length
523 encoding). Filtered data consists mostly of small values with a somewhat
524 random distribution. In this case, the compression algorithm is tuned to
525 compress them better. The effect of Z_FILTERED is to force more Huffman
526 coding and less string matching; it is somewhat intermediate between
527 Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
528 Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
529 parameter only affects the compression ratio but not the correctness of the
530 compressed output even if it is not set appropriately. Z_FIXED prevents the
531 use of dynamic Huffman codes, allowing for a simpler decoder for special
532 applications.
534 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
535 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
536 method). msg is set to null if there is no error message. deflateInit2 does
537 not perform any compression: this will be done by deflate().
538 */
542 uInt dictLength));
543 /*
544 Initializes the compression dictionary from the given byte sequence
545 without producing any compressed output. This function must be called
546 immediately after deflateInit, deflateInit2 or deflateReset, before any
547 call of deflate. The compressor and decompressor must use exactly the same
548 dictionary (see inflateSetDictionary).
550 The dictionary should consist of strings (byte sequences) that are likely
551 to be encountered later in the data to be compressed, with the most commonly
552 used strings preferably put towards the end of the dictionary. Using a
553 dictionary is most useful when the data to be compressed is short and can be
554 predicted with good accuracy; the data can then be compressed better than
555 with the default empty dictionary.
557 Depending on the size of the compression data structures selected by
558 deflateInit or deflateInit2, a part of the dictionary may in effect be
559 discarded, for example if the dictionary is larger than the window size in
560 deflate or deflate2. Thus the strings most likely to be useful should be
561 put at the end of the dictionary, not at the front. In addition, the
562 current implementation of deflate will use at most the window size minus
563 262 bytes of the provided dictionary.
565 Upon return of this function, strm->adler is set to the adler32 value
566 of the dictionary; the decompressor may later use this value to determine
567 which dictionary has been used by the compressor. (The adler32 value
568 applies to the whole dictionary even if only a subset of the dictionary is
569 actually used by the compressor.) If a raw deflate was requested, then the
570 adler32 value is not computed and strm->adler is not set.
572 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
573 parameter is invalid (such as NULL dictionary) or the stream state is
574 inconsistent (for example if deflate has already been called for this stream
575 or if the compression method is bsort). deflateSetDictionary does not
576 perform any compression: this will be done by deflate().
577 */
580 z_streamp source));
581 /*
582 Sets the destination stream as a complete copy of the source stream.
584 This function can be useful when several compression strategies will be
585 tried, for example when there are several ways of pre-processing the input
586 data with a filter. The streams that will be discarded should then be freed
587 by calling deflateEnd. Note that deflateCopy duplicates the internal
588 compression state which can be quite large, so this strategy is slow and
589 can consume lots of memory.
591 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
592 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
593 (such as zalloc being NULL). msg is left unchanged in both source and
594 destination.
595 */
598 /*
599 This function is equivalent to deflateEnd followed by deflateInit,
600 but does not free and reallocate all the internal compression state.
601 The stream will keep the same compression level and any other attributes
602 that may have been set by deflateInit2.
604 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
605 stream state was inconsistent (such as zalloc or state being NULL).
606 */
611 /*
612 Dynamically update the compression level and compression strategy. The
613 interpretation of level and strategy is as in deflateInit2. This can be
614 used to switch between compression and straight copy of the input data, or
615 to switch to a different kind of input data requiring a different
616 strategy. If the compression level is changed, the input available so far
617 is compressed with the old level (and may be flushed); the new level will
618 take effect only at the next call of deflate().
620 Before the call of deflateParams, the stream state must be set as for
621 a call of deflate(), since the currently available input may have to
622 be compressed and flushed. In particular, strm->avail_out must be non-zero.
624 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
625 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
626 if strm->avail_out was zero.
627 */
634 /*
635 Fine tune deflate's internal compression parameters. This should only be
636 used by someone who understands the algorithm used by zlib's deflate for
637 searching for the best matching string, and even then only by the most
638 fanatic optimizer trying to squeeze out the last compressed bit for their
639 specific input data. Read the deflate.c source code for the meaning of the
640 max_lazy, good_length, nice_length, and max_chain parameters.
642 deflateTune() can be called after deflateInit() or deflateInit2(), and
643 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
644 */
647 uLong sourceLen));
648 /*
649 deflateBound() returns an upper bound on the compressed size after
650 deflation of sourceLen bytes. It must be called after deflateInit()
651 or deflateInit2(). This would be used to allocate an output buffer
652 for deflation in a single pass, and so would be called before deflate().
653 */
658 /*
659 deflatePrime() inserts bits in the deflate output stream. The intent
660 is that this function is used to start off the deflate output with the
661 bits leftover from a previous deflate stream when appending to it. As such,
662 this function can only be used for raw deflate, and must be used before the
663 first deflate() call after a deflateInit2() or deflateReset(). bits must be
664 less than or equal to 16, and that many of the least significant bits of
665 value will be inserted in the output.
667 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
668 stream state was inconsistent.
669 */
672 gz_headerp head));
673 /*
674 deflateSetHeader() provides gzip header information for when a gzip
675 stream is requested by deflateInit2(). deflateSetHeader() may be called
676 after deflateInit2() or deflateReset() and before the first call of
677 deflate(). The text, time, os, extra field, name, and comment information
678 in the provided gz_header structure are written to the gzip header (xflag is
679 ignored -- the extra flags are set according to the compression level). The
680 caller must assure that, if not Z_NULL, name and comment are terminated with
681 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
682 available there. If hcrc is true, a gzip header crc is included. Note that
683 the current versions of the command-line version of gzip (up through version
684 1.3.x) do not support header crc's, and will report that it is a "multi-part
685 gzip file" and give up.
687 If deflateSetHeader is not used, the default gzip header has text false,
688 the time set to zero, and os set to 255, with no extra, name, or comment
689 fields. The gzip header is returned to the default state by deflateReset().
691 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
692 stream state was inconsistent.
693 */
695 /*
696 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
697 int windowBits));
699 This is another version of inflateInit with an extra parameter. The
700 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
701 before by the caller.
703 The windowBits parameter is the base two logarithm of the maximum window
704 size (the size of the history buffer). It should be in the range 8..15 for
705 this version of the library. The default value is 15 if inflateInit is used
706 instead. windowBits must be greater than or equal to the windowBits value
707 provided to deflateInit2() while compressing, or it must be equal to 15 if
708 deflateInit2() was not used. If a compressed stream with a larger window
709 size is given as input, inflate() will return with the error code
710 Z_DATA_ERROR instead of trying to allocate a larger window.
712 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
713 determines the window size. inflate() will then process raw deflate data,
714 not looking for a zlib or gzip header, not generating a check value, and not
715 looking for any check values for comparison at the end of the stream. This
716 is for use with other formats that use the deflate compressed data format
717 such as zip. Those formats provide their own check values. If a custom
718 format is developed using the raw deflate format for compressed data, it is
719 recommended that a check value such as an adler32 or a crc32 be applied to
720 the uncompressed data as is done in the zlib, gzip, and zip formats. For
721 most applications, the zlib format should be used as is. Note that comments
722 above on the use in deflateInit2() applies to the magnitude of windowBits.
724 windowBits can also be greater than 15 for optional gzip decoding. Add
725 32 to windowBits to enable zlib and gzip decoding with automatic header
726 detection, or add 16 to decode only the gzip format (the zlib format will
727 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
728 a crc32 instead of an adler32.
730 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
731 memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
732 is set to null if there is no error message. inflateInit2 does not perform
733 any decompression apart from reading the zlib header if present: this will
734 be done by inflate(). (So next_in and avail_in may be modified, but next_out
735 and avail_out are unchanged.)
736 */
740 uInt dictLength));
741 /*
742 Initializes the decompression dictionary from the given uncompressed byte
743 sequence. This function must be called immediately after a call of inflate,
744 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
745 can be determined from the adler32 value returned by that call of inflate.
746 The compressor and decompressor must use exactly the same dictionary (see
747 deflateSetDictionary). For raw inflate, this function can be called
748 immediately after inflateInit2() or inflateReset() and before any call of
749 inflate() to set the dictionary. The application must insure that the
750 dictionary that was used for compression is provided.
752 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
753 parameter is invalid (such as NULL dictionary) or the stream state is
754 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
755 expected one (incorrect adler32 value). inflateSetDictionary does not
756 perform any decompression: this will be done by subsequent calls of
757 inflate().
758 */
761 /*
762 Skips invalid compressed data until a full flush point (see above the
763 description of deflate with Z_FULL_FLUSH) can be found, or until all
764 available input is skipped. No output is provided.
766 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
767 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
768 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
769 case, the application may save the current current value of total_in which
770 indicates where valid compressed data was found. In the error case, the
771 application may repeatedly call inflateSync, providing more input each time,
772 until success or end of the input data.
773 */
776 z_streamp source));
777 /*
778 Sets the destination stream as a complete copy of the source stream.
780 This function can be useful when randomly accessing a large stream. The
781 first pass through the stream can periodically record the inflate state,
782 allowing restarting inflate at those points when randomly accessing the
783 stream.
785 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
786 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
787 (such as zalloc being NULL). msg is left unchanged in both source and
788 destination.
789 */
792 /*
793 This function is equivalent to inflateEnd followed by inflateInit,
794 but does not free and reallocate all the internal decompression state.
795 The stream will keep attributes that may have been set by inflateInit2.
797 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
798 stream state was inconsistent (such as zalloc or state being NULL).
799 */
804 /*
805 This function inserts bits in the inflate input stream. The intent is
806 that this function is used to start inflating at a bit position in the
807 middle of a byte. The provided bits will be used before any bytes are used
808 from next_in. This function should only be used with raw inflate, and
809 should be used before the first inflate() call after inflateInit2() or
810 inflateReset(). bits must be less than or equal to 16, and that many of the
811 least significant bits of value will be inserted in the input.
813 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
814 stream state was inconsistent.
815 */
818 gz_headerp head));
819 /*
820 inflateGetHeader() requests that gzip header information be stored in the
821 provided gz_header structure. inflateGetHeader() may be called after
822 inflateInit2() or inflateReset(), and before the first call of inflate().
823 As inflate() processes the gzip stream, head->done is zero until the header
824 is completed, at which time head->done is set to one. If a zlib stream is
825 being decoded, then head->done is set to -1 to indicate that there will be
826 no gzip header information forthcoming. Note that Z_BLOCK can be used to
827 force inflate() to return immediately after header processing is complete
828 and before any actual data is decompressed.
830 The text, time, xflags, and os fields are filled in with the gzip header
831 contents. hcrc is set to true if there is a header CRC. (The header CRC
832 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
833 contains the maximum number of bytes to write to extra. Once done is true,
834 extra_len contains the actual extra field length, and extra contains the
835 extra field, or that field truncated if extra_max is less than extra_len.
836 If name is not Z_NULL, then up to name_max characters are written there,
837 terminated with a zero unless the length is greater than name_max. If
838 comment is not Z_NULL, then up to comm_max characters are written there,
839 terminated with a zero unless the length is greater than comm_max. When
840 any of extra, name, or comment are not Z_NULL and the respective field is
841 not present in the header, then that field is set to Z_NULL to signal its
842 absence. This allows the use of deflateSetHeader() with the returned
843 structure to duplicate the header. However if those fields are set to
844 allocated memory, then the application will need to save those pointers
845 elsewhere so that they can be eventually freed.
847 If inflateGetHeader is not used, then the header information is simply
848 discarded. The header is always checked for validity, including the header
849 CRC if present. inflateReset() will reset the process to discard the header
850 information. The application would need to call inflateGetHeader() again to
851 retrieve the header from the next gzip stream.
853 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
854 stream state was inconsistent.
855 */
857 /*
858 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
859 unsigned char FAR *window));
861 Initialize the internal stream state for decompression using inflateBack()
862 calls. The fields zalloc, zfree and opaque in strm must be initialized
863 before the call. If zalloc and zfree are Z_NULL, then the default library-
864 derived memory allocation routines are used. windowBits is the base two
865 logarithm of the window size, in the range 8..15. window is a caller
866 supplied buffer of that size. Except for special applications where it is
867 assured that deflate was used with small window sizes, windowBits must be 15
868 and a 32K byte window must be supplied to be able to decompress general
869 deflate streams.
871 See inflateBack() for the usage of these routines.
873 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
874 the paramaters are invalid, Z_MEM_ERROR if the internal state could not
875 be allocated, or Z_VERSION_ERROR if the version of the library does not
876 match the version of the header file.
877 */
885 /*
886 inflateBack() does a raw inflate with a single call using a call-back
887 interface for input and output. This is more efficient than inflate() for
888 file i/o applications in that it avoids copying between the output and the
889 sliding window by simply making the window itself the output buffer. This
890 function trusts the application to not change the output buffer passed by
891 the output function, at least until inflateBack() returns.
893 inflateBackInit() must be called first to allocate the internal state
894 and to initialize the state with the user-provided window buffer.
895 inflateBack() may then be used multiple times to inflate a complete, raw
896 deflate stream with each call. inflateBackEnd() is then called to free
897 the allocated state.
899 A raw deflate stream is one with no zlib or gzip header or trailer.
900 This routine would normally be used in a utility that reads zip or gzip
901 files and writes out uncompressed files. The utility would decode the
902 header and process the trailer on its own, hence this routine expects
903 only the raw deflate stream to decompress. This is different from the
904 normal behavior of inflate(), which expects either a zlib or gzip header and
905 trailer around the deflate stream.
907 inflateBack() uses two subroutines supplied by the caller that are then
908 called by inflateBack() for input and output. inflateBack() calls those
909 routines until it reads a complete deflate stream and writes out all of the
910 uncompressed data, or until it encounters an error. The function's
911 parameters and return types are defined above in the in_func and out_func
912 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
913 number of bytes of provided input, and a pointer to that input in buf. If
914 there is no input available, in() must return zero--buf is ignored in that
915 case--and inflateBack() will return a buffer error. inflateBack() will call
916 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
917 should return zero on success, or non-zero on failure. If out() returns
918 non-zero, inflateBack() will return with an error. Neither in() nor out()
919 are permitted to change the contents of the window provided to
920 inflateBackInit(), which is also the buffer that out() uses to write from.
921 The length written by out() will be at most the window size. Any non-zero
922 amount of input may be provided by in().
924 For convenience, inflateBack() can be provided input on the first call by
925 setting strm->next_in and strm->avail_in. If that input is exhausted, then
926 in() will be called. Therefore strm->next_in must be initialized before
927 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
928 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
929 must also be initialized, and then if strm->avail_in is not zero, input will
930 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
932 The in_desc and out_desc parameters of inflateBack() is passed as the
933 first parameter of in() and out() respectively when they are called. These
934 descriptors can be optionally used to pass any information that the caller-
935 supplied in() and out() functions need to do their job.
937 On return, inflateBack() will set strm->next_in and strm->avail_in to
938 pass back any unused input that was provided by the last in() call. The
939 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
940 if in() or out() returned an error, Z_DATA_ERROR if there was a format
941 error in the deflate stream (in which case strm->msg is set to indicate the
942 nature of the error), or Z_STREAM_ERROR if the stream was not properly
943 initialized. In the case of Z_BUF_ERROR, an input or output error can be
944 distinguished using strm->next_in which will be Z_NULL only if in() returned
945 an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
946 out() returning non-zero. (in() will always be called before out(), so
947 strm->next_in is assured to be defined if out() returns non-zero.) Note
948 that inflateBack() cannot return Z_OK.
949 */
952 /*
953 All memory allocated by inflateBackInit() is freed.
955 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
956 state was inconsistent.
957 */
960 /* Return flags indicating compile-time options.
962 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
963 1.0: size of uInt
964 3.2: size of uLong
965 5.4: size of voidpf (pointer)
966 7.6: size of z_off_t
968 Compiler, assembler, and debug options:
969 8: ZLIB_DEBUG
970 9: ASMV or ASMINF -- use ASM code
971 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
972 11: 0 (reserved)
974 One-time table building (smaller code, but not thread-safe if true):
975 12: BUILDFIXED -- build static block decoding tables when needed
976 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
977 14,15: 0 (reserved)
979 Library content (indicates missing functionality):
980 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
981 deflate code when not needed)
982 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
983 and decode gzip streams (to avoid linking crc code)
984 18-19: 0 (reserved)
986 Operation variations (changes in library functionality):
987 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
988 21: FASTEST -- deflate algorithm with only one, lowest compression level
989 22,23: 0 (reserved)
991 The sprintf variant used by gzprintf (zero is best):
992 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
993 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
994 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
996 Remainder:
997 27-31: 0 (reserved)
998 */
1001 /* utility functions */
1003 /*
1004 The following utility functions are implemented on top of the
1005 basic stream-oriented functions. To simplify the interface, some
1006 default options are assumed (compression level and memory usage,
1007 standard memory allocation functions). The source code of these
1008 utility functions can easily be modified if you need special options.
1009 */
1013 /*
1014 Compresses the source buffer into the destination buffer. sourceLen is
1015 the byte length of the source buffer. Upon entry, destLen is the total
1016 size of the destination buffer, which must be at least the value returned
1017 by compressBound(sourceLen). Upon exit, destLen is the actual size of the
1018 compressed buffer.
1019 This function can be used to compress a whole file at once if the
1020 input file is mmap'ed.
1021 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1022 enough memory, Z_BUF_ERROR if there was not enough room in the output
1023 buffer.
1024 */
1029 /*
1030 Compresses the source buffer into the destination buffer. The level
1031 parameter has the same meaning as in deflateInit. sourceLen is the byte
1032 length of the source buffer. Upon entry, destLen is the total size of the
1033 destination buffer, which must be at least the value returned by
1034 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1035 compressed buffer.
1037 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1038 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1039 Z_STREAM_ERROR if the level parameter is invalid.
1040 */
1043 /*
1044 compressBound() returns an upper bound on the compressed size after
1045 compress() or compress2() on sourceLen bytes. It would be used before
1046 a compress() or compress2() call to allocate the destination buffer.
1047 */
1051 /*
1052 Decompresses the source buffer into the destination buffer. sourceLen is
1053 the byte length of the source buffer. Upon entry, destLen is the total
1054 size of the destination buffer, which must be large enough to hold the
1055 entire uncompressed data. (The size of the uncompressed data must have
1056 been saved previously by the compressor and transmitted to the decompressor
1057 by some mechanism outside the scope of this compression library.)
1058 Upon exit, destLen is the actual size of the compressed buffer.
1059 This function can be used to decompress a whole file at once if the
1060 input file is mmap'ed.
1062 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1063 enough memory, Z_BUF_ERROR if there was not enough room in the output
1064 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
1065 */
1071 /*
1072 Opens a gzip (.gz) file for reading or writing. The mode parameter
1073 is as in fopen ("rb" or "wb") but can also include a compression level
1074 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
1075 Huffman only compression as in "wb1h", or 'R' for run-length encoding
1076 as in "wb1R". (See the description of deflateInit2 for more information
1077 about the strategy parameter.)
1079 gzopen can be used to read a file which is not in gzip format; in this
1080 case gzread will directly read from the file without decompression.
1082 gzopen returns NULL if the file could not be opened or if there was
1083 insufficient memory to allocate the (de)compression state; errno
1084 can be checked to distinguish the two cases (if errno is zero, the
1085 zlib error is Z_MEM_ERROR). */
1088 /*
1089 gzdopen() associates a gzFile with the file descriptor fd. File
1090 descriptors are obtained from calls like open, dup, creat, pipe or
1091 fileno (in the file has been previously opened with fopen).
1092 The mode parameter is as in gzopen.
1093 The next call of gzclose on the returned gzFile will also close the
1094 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
1095 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
1096 gzdopen returns NULL if there was insufficient memory to allocate
1097 the (de)compression state.
1098 */
1101 /*
1102 Dynamically update the compression level or strategy. See the description
1103 of deflateInit2 for the meaning of these parameters.
1104 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1105 opened for writing.
1106 */
1109 /*
1110 Reads the given number of uncompressed bytes from the compressed file.
1111 If the input file was not in gzip format, gzread copies the given number
1112 of bytes into the buffer.
1113 gzread returns the number of uncompressed bytes actually read (0 for
1114 end of file, -1 for error). */
1118 /*
1119 Writes the given number of uncompressed bytes into the compressed file.
1120 gzwrite returns the number of uncompressed bytes actually written
1121 (0 in case of error).
1122 */
1125 /*
1126 Converts, formats, and writes the args to the compressed file under
1127 control of the format string, as in fprintf. gzprintf returns the number of
1128 uncompressed bytes actually written (0 in case of error). The number of
1129 uncompressed bytes written is limited to 4095. The caller should assure that
1130 this limit is not exceeded. If it is exceeded, then gzprintf() will return
1131 return an error (0) with nothing written. In this case, there may also be a
1132 buffer overflow with unpredictable consequences, which is possible only if
1133 zlib was compiled with the insecure functions sprintf() or vsprintf()
1134 because the secure snprintf() or vsnprintf() functions were not available.
1135 */
1138 /*
1139 Writes the given null-terminated string to the compressed file, excluding
1140 the terminating null character.
1141 gzputs returns the number of characters written, or -1 in case of error.
1142 */
1145 /*
1146 Reads bytes from the compressed file until len-1 characters are read, or
1147 a newline character is read and transferred to buf, or an end-of-file
1148 condition is encountered. The string is then terminated with a null
1149 character.
1150 gzgets returns buf, or Z_NULL in case of error.
1151 */
1154 /*
1155 Writes c, converted to an unsigned char, into the compressed file.
1156 gzputc returns the value that was written, or -1 in case of error.
1157 */
1160 /*
1161 Reads one byte from the compressed file. gzgetc returns this byte
1162 or -1 in case of end of file or error.
1163 */
1166 /*
1167 Push one character back onto the stream to be read again later.
1168 Only one character of push-back is allowed. gzungetc() returns the
1169 character pushed, or -1 on failure. gzungetc() will fail if a
1170 character has been pushed but not read yet, or if c is -1. The pushed
1171 character will be discarded if the stream is repositioned with gzseek()
1172 or gzrewind().
1173 */
1176 /*
1177 Flushes all pending output into the compressed file. The parameter
1178 flush is as in the deflate() function. The return value is the zlib
1179 error number (see function gzerror below). gzflush returns Z_OK if
1180 the flush parameter is Z_FINISH and all output could be flushed.
1181 gzflush should be called only when strictly necessary because it can
1182 degrade compression.
1183 */
1187 /*
1188 Sets the starting position for the next gzread or gzwrite on the
1189 given compressed file. The offset represents a number of bytes in the
1190 uncompressed data stream. The whence parameter is defined as in lseek(2);
1191 the value SEEK_END is not supported.
1192 If the file is opened for reading, this function is emulated but can be
1193 extremely slow. If the file is opened for writing, only forward seeks are
1194 supported; gzseek then compresses a sequence of zeroes up to the new
1195 starting position.
1197 gzseek returns the resulting offset location as measured in bytes from
1198 the beginning of the uncompressed stream, or -1 in case of error, in
1199 particular if the file is opened for writing and the new starting position
1200 would be before the current position.
1201 */
1204 /*
1205 Rewinds the given file. This function is supported only for reading.
1207 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1208 */
1211 /*
1212 Returns the starting position for the next gzread or gzwrite on the
1213 given compressed file. This position represents a number of bytes in the
1214 uncompressed data stream.
1216 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1217 */
1220 /*
1221 Returns 1 when EOF has previously been detected reading the given
1222 input stream, otherwise zero.
1223 */
1226 /*
1227 Returns 1 if file is being read directly without decompression, otherwise
1228 zero.
1229 */
1232 /*
1233 Flushes all pending output if necessary, closes the compressed file
1234 and deallocates all the (de)compression state. The return value is the zlib
1235 error number (see function gzerror below).
1236 */
1239 /*
1240 Returns the error message for the last error which occurred on the
1241 given compressed file. errnum is set to zlib error number. If an
1242 error occurred in the file system and not in the compression library,
1243 errnum is set to Z_ERRNO and the application may consult errno
1244 to get the exact error code.
1245 */
1248 /*
1249 Clears the error and end-of-file flags for file. This is analogous to the
1250 clearerr() function in stdio. This is useful for continuing to read a gzip
1251 file that is being written concurrently.
1252 */
1254 /* checksum functions */
1256 /*
1257 These functions are not related to compression but are exported
1258 anyway because they might be useful in applications using the
1259 compression library.
1260 */
1263 /*
1264 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1265 return the updated checksum. If buf is NULL, this function returns
1266 the required initial value for the checksum.
1267 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1268 much faster. Usage example:
1270 uLong adler = adler32(0L, Z_NULL, 0);
1272 while (read_buffer(buffer, length) != EOF) {
1273 adler = adler32(adler, buffer, length);
1274 }
1275 if (adler != original_adler) error();
1276 */
1279 z_off_t len2));
1280 /*
1281 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1282 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1283 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1284 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
1285 */
1287 #if !defined(_KERNEL) && !defined(_STANDALONE)
1289 #endif
1290 /*
1291 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1292 updated CRC-32. If buf is NULL, this function returns the required initial
1293 value for the for the crc. Pre- and post-conditioning (one's complement) is
1294 performed within this function so it shouldn't be done by the application.
1295 Usage example:
1297 uLong crc = crc32(0L, Z_NULL, 0);
1299 while (read_buffer(buffer, length) != EOF) {
1300 crc = crc32(crc, buffer, length);
1301 }
1302 if (crc != original_crc) error();
1303 */
1307 /*
1308 Combine two CRC-32 check values into one. For two sequences of bytes,
1309 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1310 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1311 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1312 len2.
1313 */
1316 /* various hacks, don't look :) */
1318 /* deflateInit and inflateInit are macros to allow checking the zlib version
1319 * and the compiler's view of z_stream:
1320 */
1335 #define deflateInit(strm, level) \
1336 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
1337 #define inflateInit(strm) \
1338 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
1339 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1340 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1341 (strategy), ZLIB_VERSION, sizeof(z_stream))
1342 #define inflateInit2(strm, windowBits) \
1343 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
1344 #define inflateBackInit(strm, windowBits, window) \
1345 inflateBackInit_((strm), (windowBits), (window), \
1346 ZLIB_VERSION, sizeof(z_stream))
1349 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1351 #endif
1357 #ifdef __cplusplus
1358 }
1359 #endif