master
1/* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.2.12, March 11th, 2022
3
4 Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler
5
6 This software is provided 'as-is', without any express or implied
7 warranty. In no event will the authors be held liable for any damages
8 arising from the use of this software.
9
10 Permission is granted to anyone to use this software for any purpose,
11 including commercial applications, and to alter it and redistribute it
12 freely, subject to the following restrictions:
13
14 1. The origin of this software must not be misrepresented; you must not
15 claim that you wrote the original software. If you use this software
16 in a product, an acknowledgment in the product documentation would be
17 appreciated but is not required.
18 2. Altered source versions must be plainly marked as such, and must not be
19 misrepresented as being the original software.
20 3. This notice may not be removed or altered from any source distribution.
21
22 Jean-loup Gailly Mark Adler
23 jloup@gzip.org madler@alumni.caltech.edu
24
25
26 The data format used by the zlib library is described by RFCs (Request for
27 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
28 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
29*/
30
31#ifndef ZLIB_H
32#define ZLIB_H
33
34#include "zconf.h"
35
36#ifdef __APPLE__
37#include <Availability.h>
38#else /* !__APPLE__ */
39#define __API_AVAILABLE(...) /* nothing */
40#endif /* !__APPLE__ */
41
42#ifdef __cplusplus
43extern "C" {
44#endif
45
46#define ZLIB_VERSION "1.2.12"
47#define ZLIB_VERNUM 0x12c0
48#define ZLIB_VER_MAJOR 1
49#define ZLIB_VER_MINOR 2
50#define ZLIB_VER_REVISION 12
51#define ZLIB_VER_SUBREVISION 0
52
53/*
54 The 'zlib' compression library provides in-memory compression and
55 decompression functions, including integrity checks of the uncompressed data.
56 This version of the library supports only one compression method (deflation)
57 but other algorithms will be added later and will have the same stream
58 interface.
59
60 Compression can be done in a single step if the buffers are large enough,
61 or can be done by repeated calls of the compression function. In the latter
62 case, the 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 using the functions that start
71 with "gz". The gzip format is different from the zlib format. gzip is a
72 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
73
74 This library can optionally read and write gzip and raw deflate streams in
75 memory as well.
76
77 The zlib format was designed to be compact and fast for use in memory
78 and on communications channels. The gzip format was designed for single-
79 file compression on file systems, has a larger header than zlib to maintain
80 directory information, and uses a different, slower check method than zlib.
81
82 The library does not install any signal handler. The decoder checks
83 the consistency of the compressed data, so the library should never crash
84 even in the case of corrupted input.
85*/
86
87typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
88typedef void (*free_func) OF((voidpf opaque, voidpf address));
89
90struct internal_state;
91
92typedef struct z_stream_s {
93 z_const Bytef *next_in; /* next input byte */
94 uInt avail_in; /* number of bytes available at next_in */
95 uLong total_in; /* total number of input bytes read so far */
96
97 Bytef *next_out; /* next output byte will go here */
98 uInt avail_out; /* remaining free space at next_out */
99 uLong total_out; /* total number of bytes output so far */
100
101 z_const char *msg; /* last error message, NULL if no error */
102 struct internal_state FAR *state; /* not visible by applications */
103
104 alloc_func zalloc; /* used to allocate the internal state */
105 free_func zfree; /* used to free the internal state */
106 voidpf opaque; /* private data object passed to zalloc and zfree */
107
108 int data_type; /* best guess about the data type: binary or text
109 for deflate, or the decoding state for inflate */
110 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */
111 uLong reserved; /* reserved for future use */
112} z_stream;
113
114typedef z_stream FAR *z_streamp;
115
116/*
117 gzip header information passed to and from zlib routines. See RFC 1952
118 for more details on the meanings of these fields.
119*/
120typedef struct gz_header_s {
121 int text; /* true if compressed data believed to be text */
122 uLong time; /* modification time */
123 int xflags; /* extra flags (not used when writing a gzip file) */
124 int os; /* operating system */
125 Bytef *extra; /* pointer to extra field or Z_NULL if none */
126 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
127 uInt extra_max; /* space at extra (only when reading header) */
128 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
129 uInt name_max; /* space at name (only when reading header) */
130 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
131 uInt comm_max; /* space at comment (only when reading header) */
132 int hcrc; /* true if there was or will be a header crc */
133 int done; /* true when done reading gzip header (not used
134 when writing a gzip file) */
135} gz_header;
136
137typedef gz_header FAR *gz_headerp;
138
139/*
140 The application must update next_in and avail_in when avail_in has dropped
141 to zero. It must update next_out and avail_out when avail_out has dropped
142 to zero. The application must initialize zalloc, zfree and opaque before
143 calling the init function. All other fields are set by the compression
144 library and must not be updated by the application.
145
146 The opaque value provided by the application will be passed as the first
147 parameter for calls of zalloc and zfree. This can be useful for custom
148 memory management. The compression library attaches no meaning to the
149 opaque value.
150
151 zalloc must return Z_NULL if there is not enough memory for the object.
152 If zlib is used in a multi-threaded application, zalloc and zfree must be
153 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
154 Z_NULL on entry to the initialization function, they are set to internal
155 routines that use the standard library functions malloc() and free().
156
157 On 16-bit systems, the functions zalloc and zfree must be able to allocate
158 exactly 65536 bytes, but will not be required to allocate more than this if
159 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
160 returned by zalloc for objects of exactly 65536 bytes *must* have their
161 offset normalized to zero. The default allocation function provided by this
162 library ensures this (see zutil.c). To reduce memory requirements and avoid
163 any allocation of 64K objects, at the expense of compression ratio, compile
164 the library with -DMAX_WBITS=14 (see zconf.h).
165
166 The fields total_in and total_out can be used for statistics or progress
167 reports. After compression, total_in holds the total size of the
168 uncompressed data and may be saved for use by the decompressor (particularly
169 if the decompressor wants to decompress everything in a single step).
170*/
171
172 /* constants */
173
174#define Z_NO_FLUSH 0
175#define Z_PARTIAL_FLUSH 1
176#define Z_SYNC_FLUSH 2
177#define Z_FULL_FLUSH 3
178#define Z_FINISH 4
179#define Z_BLOCK 5
180#define Z_TREES 6
181/* Allowed flush values; see deflate() and inflate() below for details */
182
183#define Z_OK 0
184#define Z_STREAM_END 1
185#define Z_NEED_DICT 2
186#define Z_ERRNO (-1)
187#define Z_STREAM_ERROR (-2)
188#define Z_DATA_ERROR (-3)
189#define Z_MEM_ERROR (-4)
190#define Z_BUF_ERROR (-5)
191#define Z_VERSION_ERROR (-6)
192/* Return codes for the compression/decompression functions. Negative values
193 * are errors, positive values are used for special but normal events.
194 */
195
196#define Z_NO_COMPRESSION 0
197#define Z_BEST_SPEED 1
198#define Z_BEST_COMPRESSION 9
199#define Z_DEFAULT_COMPRESSION (-1)
200/* compression levels */
201
202#define Z_FILTERED 1
203#define Z_HUFFMAN_ONLY 2
204#define Z_RLE 3
205#define Z_FIXED 4
206#define Z_DEFAULT_STRATEGY 0
207/* compression strategy; see deflateInit2() below for details */
208
209#define Z_BINARY 0
210#define Z_TEXT 1
211#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
212#define Z_UNKNOWN 2
213/* Possible values of the data_type field for deflate() */
214
215#define Z_DEFLATED 8
216/* The deflate compression method (the only one supported in this version) */
217
218#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
219
220#define zlib_version zlibVersion()
221/* for compatibility with versions < 1.0.2 */
222
223
224 /* basic functions */
225
226ZEXTERN const char * ZEXPORT zlibVersion OF((void));
227/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
228 If the first character differs, the library code actually used is not
229 compatible with the zlib.h header file used by the application. This check
230 is automatically made by deflateInit and inflateInit.
231 */
232
233/*
234ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
235
236 Initializes the internal stream state for compression. The fields
237 zalloc, zfree and opaque must be initialized before by the caller. If
238 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
239 allocation functions.
240
241 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
242 1 gives best speed, 9 gives best compression, 0 gives no compression at all
243 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
244 requests a default compromise between speed and compression (currently
245 equivalent to level 6).
246
247 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
248 memory, Z_STREAM_ERROR if level is not a valid compression level, or
249 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
250 with the version assumed by the caller (ZLIB_VERSION). msg is set to null
251 if there is no error message. deflateInit does not perform any compression:
252 this will be done by deflate().
253*/
254
255
256ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
257/*
258 deflate compresses as much data as possible, and stops when the input
259 buffer becomes empty or the output buffer becomes full. It may introduce
260 some output latency (reading input without producing any output) except when
261 forced to flush.
262
263 The detailed semantics are as follows. deflate performs one or both of the
264 following actions:
265
266 - Compress more input starting at next_in and update next_in and avail_in
267 accordingly. If not all input can be processed (because there is not
268 enough room in the output buffer), next_in and avail_in are updated and
269 processing will resume at this point for the next call of deflate().
270
271 - Generate more output starting at next_out and update next_out and avail_out
272 accordingly. This action is forced if the parameter flush is non zero.
273 Forcing flush frequently degrades the compression ratio, so this parameter
274 should be set only when necessary. Some output may be provided even if
275 flush is zero.
276
277 Before the call of deflate(), the application should ensure that at least
278 one of the actions is possible, by providing more input and/or consuming more
279 output, and updating avail_in or avail_out accordingly; avail_out should
280 never be zero before the call. The application can consume the compressed
281 output when it wants, for example when the output buffer is full (avail_out
282 == 0), or after each call of deflate(). If deflate returns Z_OK and with
283 zero avail_out, it must be called again after making room in the output
284 buffer because there might be more output pending. See deflatePending(),
285 which can be used if desired to determine whether or not there is more ouput
286 in that case.
287
288 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
289 decide how much data to accumulate before producing output, in order to
290 maximize compression.
291
292 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
293 flushed to the output buffer and the output is aligned on a byte boundary, so
294 that the decompressor can get all input data available so far. (In
295 particular avail_in is zero after the call if enough output space has been
296 provided before the call.) Flushing may degrade compression for some
297 compression algorithms and so it should be used only when necessary. This
298 completes the current deflate block and follows it with an empty stored block
299 that is three bits plus filler bits to the next byte, followed by four bytes
300 (00 00 ff ff).
301
302 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
303 output buffer, but the output is not aligned to a byte boundary. All of the
304 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
305 This completes the current deflate block and follows it with an empty fixed
306 codes block that is 10 bits long. This assures that enough bytes are output
307 in order for the decompressor to finish the block before the empty fixed
308 codes block.
309
310 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
311 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
312 seven bits of the current block are held to be written as the next byte after
313 the next deflate block is completed. In this case, the decompressor may not
314 be provided enough bits at this point in order to complete decompression of
315 the data provided so far to the compressor. It may need to wait for the next
316 block to be emitted. This is for advanced applications that need to control
317 the emission of deflate blocks.
318
319 If flush is set to Z_FULL_FLUSH, all output is flushed as with
320 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
321 restart from this point if previous compressed data has been damaged or if
322 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
323 compression.
324
325 If deflate returns with avail_out == 0, this function must be called again
326 with the same value of the flush parameter and more output space (updated
327 avail_out), until the flush is complete (deflate returns with non-zero
328 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
329 avail_out is greater than six to avoid repeated flush markers due to
330 avail_out == 0 on return.
331
332 If the parameter flush is set to Z_FINISH, pending input is processed,
333 pending output is flushed and deflate returns with Z_STREAM_END if there was
334 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this
335 function must be called again with Z_FINISH and more output space (updated
336 avail_out) but no more input data, until it returns with Z_STREAM_END or an
337 error. After deflate has returned Z_STREAM_END, the only possible operations
338 on the stream are deflateReset or deflateEnd.
339
340 Z_FINISH can be used in the first deflate call after deflateInit if all the
341 compression is to be done in a single step. In order to complete in one
342 call, avail_out must be at least the value returned by deflateBound (see
343 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough
344 output space is provided, deflate will not return Z_STREAM_END, and it must
345 be called again as described above.
346
347 deflate() sets strm->adler to the Adler-32 checksum of all input read
348 so far (that is, total_in bytes). If a gzip stream is being generated, then
349 strm->adler will be the CRC-32 checksum of the input read so far. (See
350 deflateInit2 below.)
351
352 deflate() may update strm->data_type if it can make a good guess about
353 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is
354 considered binary. This field is only for information purposes and does not
355 affect the compression algorithm in any manner.
356
357 deflate() returns Z_OK if some progress has been made (more input
358 processed or more output produced), Z_STREAM_END if all input has been
359 consumed and all output has been produced (only when flush is set to
360 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
361 if next_in or next_out was Z_NULL or the state was inadvertently written over
362 by the application), or Z_BUF_ERROR if no progress is possible (for example
363 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
364 deflate() can be called again with more input and more output space to
365 continue compressing.
366*/
367
368
369ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
370/*
371 All dynamically allocated data structures for this stream are freed.
372 This function discards any unprocessed input and does not flush any pending
373 output.
374
375 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
376 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
377 prematurely (some input or output was discarded). In the error case, msg
378 may be set but then points to a static string (which must not be
379 deallocated).
380*/
381
382
383/*
384ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
385
386 Initializes the internal stream state for decompression. The fields
387 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
388 the caller. In the current version of inflate, the provided input is not
389 read or consumed. The allocation of a sliding window will be deferred to
390 the first call of inflate (if the decompression does not complete on the
391 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates
392 them to use default allocation functions.
393
394 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
395 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
396 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
397 invalid, such as a null pointer to the structure. msg is set to null if
398 there is no error message. inflateInit does not perform any decompression.
399 Actual decompression will be done by inflate(). So next_in, and avail_in,
400 next_out, and avail_out are unused and unchanged. The current
401 implementation of inflateInit() does not process any header information --
402 that is deferred until inflate() is called.
403*/
404
405
406ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
407/*
408 inflate decompresses as much data as possible, and stops when the input
409 buffer becomes empty or the output buffer becomes full. It may introduce
410 some output latency (reading input without producing any output) except when
411 forced to flush.
412
413 The detailed semantics are as follows. inflate performs one or both of the
414 following actions:
415
416 - Decompress more input starting at next_in and update next_in and avail_in
417 accordingly. If not all input can be processed (because there is not
418 enough room in the output buffer), then next_in and avail_in are updated
419 accordingly, and processing will resume at this point for the next call of
420 inflate().
421
422 - Generate more output starting at next_out and update next_out and avail_out
423 accordingly. inflate() provides as much output as possible, until there is
424 no more input data or no more space in the output buffer (see below about
425 the flush parameter).
426
427 Before the call of inflate(), the application should ensure that at least
428 one of the actions is possible, by providing more input and/or consuming more
429 output, and updating the next_* and avail_* values accordingly. If the
430 caller of inflate() does not provide both available input and available
431 output space, it is possible that there will be no progress made. The
432 application can consume the uncompressed output when it wants, for example
433 when the output buffer is full (avail_out == 0), or after each call of
434 inflate(). If inflate returns Z_OK and with zero avail_out, it must be
435 called again after making room in the output buffer because there might be
436 more output pending.
437
438 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
439 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
440 output as possible to the output buffer. Z_BLOCK requests that inflate()
441 stop if and when it gets to the next deflate block boundary. When decoding
442 the zlib or gzip format, this will cause inflate() to return immediately
443 after the header and before the first block. When doing a raw inflate,
444 inflate() will go ahead and process the first block, and will return when it
445 gets to the end of that block, or when it runs out of data.
446
447 The Z_BLOCK option assists in appending to or combining deflate streams.
448 To assist in this, on return inflate() always sets strm->data_type to the
449 number of unused bits in the last byte taken from strm->next_in, plus 64 if
450 inflate() is currently decoding the last block in the deflate stream, plus
451 128 if inflate() returned immediately after decoding an end-of-block code or
452 decoding the complete header up to just before the first byte of the deflate
453 stream. The end-of-block will not be indicated until all of the uncompressed
454 data from that block has been written to strm->next_out. The number of
455 unused bits may in general be greater than seven, except when bit 7 of
456 data_type is set, in which case the number of unused bits will be less than
457 eight. data_type is set as noted here every time inflate() returns for all
458 flush options, and so can be used to determine the amount of currently
459 consumed input in bits.
460
461 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
462 end of each deflate block header is reached, before any actual data in that
463 block is decoded. This allows the caller to determine the length of the
464 deflate block header for later use in random access within a deflate block.
465 256 is added to the value of strm->data_type when inflate() returns
466 immediately after reaching the end of the deflate block header.
467
468 inflate() should normally be called until it returns Z_STREAM_END or an
469 error. However if all decompression is to be performed in a single step (a
470 single call of inflate), the parameter flush should be set to Z_FINISH. In
471 this case all pending input is processed and all pending output is flushed;
472 avail_out must be large enough to hold all of the uncompressed data for the
473 operation to complete. (The size of the uncompressed data may have been
474 saved by the compressor for this purpose.) The use of Z_FINISH is not
475 required to perform an inflation in one step. However it may be used to
476 inform inflate that a faster approach can be used for the single inflate()
477 call. Z_FINISH also informs inflate to not maintain a sliding window if the
478 stream completes, which reduces inflate's memory footprint. If the stream
479 does not complete, either because not all of the stream is provided or not
480 enough output space is provided, then a sliding window will be allocated and
481 inflate() can be called again to continue the operation as if Z_NO_FLUSH had
482 been used.
483
484 In this implementation, inflate() always flushes as much output as
485 possible to the output buffer, and always uses the faster approach on the
486 first call. So the effects of the flush parameter in this implementation are
487 on the return value of inflate() as noted below, when inflate() returns early
488 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
489 memory for a sliding window when Z_FINISH is used.
490
491 If a preset dictionary is needed after this call (see inflateSetDictionary
492 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
493 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
494 strm->adler to the Adler-32 checksum of all output produced so far (that is,
495 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
496 below. At the end of the stream, inflate() checks that its computed Adler-32
497 checksum is equal to that saved by the compressor and returns Z_STREAM_END
498 only if the checksum is correct.
499
500 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
501 deflate data. The header type is detected automatically, if requested when
502 initializing with inflateInit2(). Any information contained in the gzip
503 header is not retained unless inflateGetHeader() is used. When processing
504 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
505 produced so far. The CRC-32 is checked against the gzip trailer, as is the
506 uncompressed length, modulo 2^32.
507
508 inflate() returns Z_OK if some progress has been made (more input processed
509 or more output produced), Z_STREAM_END if the end of the compressed data has
510 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
511 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
512 corrupted (input stream not conforming to the zlib format or incorrect check
513 value, in which case strm->msg points to a string with a more specific
514 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
515 next_in or next_out was Z_NULL, or the state was inadvertently written over
516 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
517 if no progress was possible or if there was not enough room in the output
518 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
519 inflate() can be called again with more input and more output space to
520 continue decompressing. If Z_DATA_ERROR is returned, the application may
521 then call inflateSync() to look for a good compression block if a partial
522 recovery of the data is to be attempted.
523*/
524
525
526ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
527/*
528 All dynamically allocated data structures for this stream are freed.
529 This function discards any unprocessed input and does not flush any pending
530 output.
531
532 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
533 was inconsistent.
534*/
535
536
537 /* Advanced functions */
538
539/*
540 The following functions are needed only in some special applications.
541*/
542
543/*
544ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
545 int level,
546 int method,
547 int windowBits,
548 int memLevel,
549 int strategy));
550
551 This is another version of deflateInit with more compression options. The
552 fields zalloc, zfree and opaque must be initialized before by the caller.
553
554 The method parameter is the compression method. It must be Z_DEFLATED in
555 this version of the library.
556
557 The windowBits parameter is the base two logarithm of the window size
558 (the size of the history buffer). It should be in the range 8..15 for this
559 version of the library. Larger values of this parameter result in better
560 compression at the expense of memory usage. The default value is 15 if
561 deflateInit is used instead.
562
563 For the current implementation of deflate(), a windowBits value of 8 (a
564 window size of 256 bytes) is not supported. As a result, a request for 8
565 will result in 9 (a 512-byte window). In that case, providing 8 to
566 inflateInit2() will result in an error when the zlib header with 9 is
567 checked against the initialization of inflate(). The remedy is to not use 8
568 with deflateInit2() with this initialization, or at least in that case use 9
569 with inflateInit2().
570
571 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
572 determines the window size. deflate() will then generate raw deflate data
573 with no zlib header or trailer, and will not compute a check value.
574
575 windowBits can also be greater than 15 for optional gzip encoding. Add
576 16 to windowBits to write a simple gzip header and trailer around the
577 compressed data instead of a zlib wrapper. The gzip header will have no
578 file name, no extra data, no comment, no modification time (set to zero), no
579 header crc, and the operating system will be set to the appropriate value,
580 if the operating system was determined at compile time. If a gzip stream is
581 being written, strm->adler is a CRC-32 instead of an Adler-32.
582
583 For raw deflate or gzip encoding, a request for a 256-byte window is
584 rejected as invalid, since only the zlib header provides a means of
585 transmitting the window size to the decompressor.
586
587 The memLevel parameter specifies how much memory should be allocated
588 for the internal compression state. memLevel=1 uses minimum memory but is
589 slow and reduces compression ratio; memLevel=9 uses maximum memory for
590 optimal speed. The default value is 8. See zconf.h for total memory usage
591 as a function of windowBits and memLevel.
592
593 The strategy parameter is used to tune the compression algorithm. Use the
594 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
595 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
596 string match), or Z_RLE to limit match distances to one (run-length
597 encoding). Filtered data consists mostly of small values with a somewhat
598 random distribution. In this case, the compression algorithm is tuned to
599 compress them better. The effect of Z_FILTERED is to force more Huffman
600 coding and less string matching; it is somewhat intermediate between
601 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
602 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
603 strategy parameter only affects the compression ratio but not the
604 correctness of the compressed output even if it is not set appropriately.
605 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
606 decoder for special applications.
607
608 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
609 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
610 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
611 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
612 set to null if there is no error message. deflateInit2 does not perform any
613 compression: this will be done by deflate().
614*/
615
616ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
617 const Bytef *dictionary,
618 uInt dictLength));
619/*
620 Initializes the compression dictionary from the given byte sequence
621 without producing any compressed output. When using the zlib format, this
622 function must be called immediately after deflateInit, deflateInit2 or
623 deflateReset, and before any call of deflate. When doing raw deflate, this
624 function must be called either before any call of deflate, or immediately
625 after the completion of a deflate block, i.e. after all input has been
626 consumed and all output has been delivered when using any of the flush
627 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
628 compressor and decompressor must use exactly the same dictionary (see
629 inflateSetDictionary).
630
631 The dictionary should consist of strings (byte sequences) that are likely
632 to be encountered later in the data to be compressed, with the most commonly
633 used strings preferably put towards the end of the dictionary. Using a
634 dictionary is most useful when the data to be compressed is short and can be
635 predicted with good accuracy; the data can then be compressed better than
636 with the default empty dictionary.
637
638 Depending on the size of the compression data structures selected by
639 deflateInit or deflateInit2, a part of the dictionary may in effect be
640 discarded, for example if the dictionary is larger than the window size
641 provided in deflateInit or deflateInit2. Thus the strings most likely to be
642 useful should be put at the end of the dictionary, not at the front. In
643 addition, the current implementation of deflate will use at most the window
644 size minus 262 bytes of the provided dictionary.
645
646 Upon return of this function, strm->adler is set to the Adler-32 value
647 of the dictionary; the decompressor may later use this value to determine
648 which dictionary has been used by the compressor. (The Adler-32 value
649 applies to the whole dictionary even if only a subset of the dictionary is
650 actually used by the compressor.) If a raw deflate was requested, then the
651 Adler-32 value is not computed and strm->adler is not set.
652
653 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
654 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
655 inconsistent (for example if deflate has already been called for this stream
656 or if not at a block boundary for raw deflate). deflateSetDictionary does
657 not perform any compression: this will be done by deflate().
658*/
659
660ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm,
661 Bytef *dictionary,
662 uInt *dictLength))
663 __API_AVAILABLE(macos(10.13),ios(11.0));
664/*
665 Returns the sliding dictionary being maintained by deflate. dictLength is
666 set to the number of bytes in the dictionary, and that many bytes are copied
667 to dictionary. dictionary must have enough space, where 32768 bytes is
668 always enough. If deflateGetDictionary() is called with dictionary equal to
669 Z_NULL, then only the dictionary length is returned, and nothing is copied.
670 Similary, if dictLength is Z_NULL, then it is not set.
671
672 deflateGetDictionary() may return a length less than the window size, even
673 when more than the window size in input has been provided. It may return up
674 to 258 bytes less in that case, due to how zlib's implementation of deflate
675 manages the sliding window and lookahead for matches, where matches can be
676 up to 258 bytes long. If the application needs the last window-size bytes of
677 input, then that would need to be saved by the application outside of zlib.
678
679 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
680 stream state is inconsistent.
681*/
682
683ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
684 z_streamp source));
685/*
686 Sets the destination stream as a complete copy of the source stream.
687
688 This function can be useful when several compression strategies will be
689 tried, for example when there are several ways of pre-processing the input
690 data with a filter. The streams that will be discarded should then be freed
691 by calling deflateEnd. Note that deflateCopy duplicates the internal
692 compression state which can be quite large, so this strategy is slow and can
693 consume lots of memory.
694
695 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
696 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
697 (such as zalloc being Z_NULL). msg is left unchanged in both source and
698 destination.
699*/
700
701ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
702/*
703 This function is equivalent to deflateEnd followed by deflateInit, but
704 does not free and reallocate the internal compression state. The stream
705 will leave the compression level and any other attributes that may have been
706 set unchanged.
707
708 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
709 stream state was inconsistent (such as zalloc or state being Z_NULL).
710*/
711
712ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
713 int level,
714 int strategy));
715/*
716 Dynamically update the compression level and compression strategy. The
717 interpretation of level and strategy is as in deflateInit2(). This can be
718 used to switch between compression and straight copy of the input data, or
719 to switch to a different kind of input data requiring a different strategy.
720 If the compression approach (which is a function of the level) or the
721 strategy is changed, and if there have been any deflate() calls since the
722 state was initialized or reset, then the input available so far is
723 compressed with the old level and strategy using deflate(strm, Z_BLOCK).
724 There are three approaches for the compression levels 0, 1..3, and 4..9
725 respectively. The new level and strategy will take effect at the next call
726 of deflate().
727
728 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
729 not have enough output space to complete, then the parameter change will not
730 take effect. In this case, deflateParams() can be called again with the
731 same parameters and more output space to try again.
732
733 In order to assure a change in the parameters on the first try, the
734 deflate stream should be flushed using deflate() with Z_BLOCK or other flush
735 request until strm.avail_out is not zero, before calling deflateParams().
736 Then no more input data should be provided before the deflateParams() call.
737 If this is done, the old level and strategy will be applied to the data
738 compressed before deflateParams(), and the new level and strategy will be
739 applied to the the data compressed after deflateParams().
740
741 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
742 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
743 there was not enough output space to complete the compression of the
744 available input data before a change in the strategy or approach. Note that
745 in the case of a Z_BUF_ERROR, the parameters are not changed. A return
746 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
747 retried with more output space.
748*/
749
750ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
751 int good_length,
752 int max_lazy,
753 int nice_length,
754 int max_chain));
755/*
756 Fine tune deflate's internal compression parameters. This should only be
757 used by someone who understands the algorithm used by zlib's deflate for
758 searching for the best matching string, and even then only by the most
759 fanatic optimizer trying to squeeze out the last compressed bit for their
760 specific input data. Read the deflate.c source code for the meaning of the
761 max_lazy, good_length, nice_length, and max_chain parameters.
762
763 deflateTune() can be called after deflateInit() or deflateInit2(), and
764 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
765 */
766
767ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
768 uLong sourceLen));
769/*
770 deflateBound() returns an upper bound on the compressed size after
771 deflation of sourceLen bytes. It must be called after deflateInit() or
772 deflateInit2(), and after deflateSetHeader(), if used. This would be used
773 to allocate an output buffer for deflation in a single pass, and so would be
774 called before deflate(). If that first deflate() call is provided the
775 sourceLen input bytes, an output buffer allocated to the size returned by
776 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
777 to return Z_STREAM_END. Note that it is possible for the compressed size to
778 be larger than the value returned by deflateBound() if flush options other
779 than Z_FINISH or Z_NO_FLUSH are used.
780*/
781
782ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
783 unsigned *pending,
784 int *bits))
785 __API_AVAILABLE(macos(10.10),ios(8.0));
786/*
787 deflatePending() returns the number of bytes and bits of output that have
788 been generated, but not yet provided in the available output. The bytes not
789 provided would be due to the available output space having being consumed.
790 The number of bits of output not provided are between 0 and 7, where they
791 await more bits to join them in order to fill out a full byte. If pending
792 or bits are Z_NULL, then those values are not set.
793
794 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
795 stream state was inconsistent.
796 */
797
798ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
799 int bits,
800 int value));
801/*
802 deflatePrime() inserts bits in the deflate output stream. The intent
803 is that this function is used to start off the deflate output with the bits
804 leftover from a previous deflate stream when appending to it. As such, this
805 function can only be used for raw deflate, and must be used before the first
806 deflate() call after a deflateInit2() or deflateReset(). bits must be less
807 than or equal to 16, and that many of the least significant bits of value
808 will be inserted in the output.
809
810 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
811 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
812 source stream state was inconsistent.
813*/
814
815ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
816 gz_headerp head));
817/*
818 deflateSetHeader() provides gzip header information for when a gzip
819 stream is requested by deflateInit2(). deflateSetHeader() may be called
820 after deflateInit2() or deflateReset() and before the first call of
821 deflate(). The text, time, os, extra field, name, and comment information
822 in the provided gz_header structure are written to the gzip header (xflag is
823 ignored -- the extra flags are set according to the compression level). The
824 caller must assure that, if not Z_NULL, name and comment are terminated with
825 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
826 available there. If hcrc is true, a gzip header crc is included. Note that
827 the current versions of the command-line version of gzip (up through version
828 1.3.x) do not support header crc's, and will report that it is a "multi-part
829 gzip file" and give up.
830
831 If deflateSetHeader is not used, the default gzip header has text false,
832 the time set to zero, and os set to 255, with no extra, name, or comment
833 fields. The gzip header is returned to the default state by deflateReset().
834
835 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
836 stream state was inconsistent.
837*/
838
839/*
840ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
841 int windowBits));
842
843 This is another version of inflateInit with an extra parameter. The
844 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
845 before by the caller.
846
847 The windowBits parameter is the base two logarithm of the maximum window
848 size (the size of the history buffer). It should be in the range 8..15 for
849 this version of the library. The default value is 15 if inflateInit is used
850 instead. windowBits must be greater than or equal to the windowBits value
851 provided to deflateInit2() while compressing, or it must be equal to 15 if
852 deflateInit2() was not used. If a compressed stream with a larger window
853 size is given as input, inflate() will return with the error code
854 Z_DATA_ERROR instead of trying to allocate a larger window.
855
856 windowBits can also be zero to request that inflate use the window size in
857 the zlib header of the compressed stream.
858
859 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
860 determines the window size. inflate() will then process raw deflate data,
861 not looking for a zlib or gzip header, not generating a check value, and not
862 looking for any check values for comparison at the end of the stream. This
863 is for use with other formats that use the deflate compressed data format
864 such as zip. Those formats provide their own check values. If a custom
865 format is developed using the raw deflate format for compressed data, it is
866 recommended that a check value such as an Adler-32 or a CRC-32 be applied to
867 the uncompressed data as is done in the zlib, gzip, and zip formats. For
868 most applications, the zlib format should be used as is. Note that comments
869 above on the use in deflateInit2() applies to the magnitude of windowBits.
870
871 windowBits can also be greater than 15 for optional gzip decoding. Add
872 32 to windowBits to enable zlib and gzip decoding with automatic header
873 detection, or add 16 to decode only the gzip format (the zlib format will
874 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
875 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see
876 below), inflate() will *not* automatically decode concatenated gzip members.
877 inflate() will return Z_STREAM_END at the end of the gzip member. The state
878 would need to be reset to continue decoding a subsequent gzip member. This
879 *must* be done if there is more data after a gzip member, in order for the
880 decompression to be compliant with the gzip standard (RFC 1952).
881
882 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
883 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
884 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
885 invalid, such as a null pointer to the structure. msg is set to null if
886 there is no error message. inflateInit2 does not perform any decompression
887 apart from possibly reading the zlib header if present: actual decompression
888 will be done by inflate(). (So next_in and avail_in may be modified, but
889 next_out and avail_out are unused and unchanged.) The current implementation
890 of inflateInit2() does not process any header information -- that is
891 deferred until inflate() is called.
892*/
893
894ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
895 const Bytef *dictionary,
896 uInt dictLength));
897/*
898 Initializes the decompression dictionary from the given uncompressed byte
899 sequence. This function must be called immediately after a call of inflate,
900 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
901 can be determined from the Adler-32 value returned by that call of inflate.
902 The compressor and decompressor must use exactly the same dictionary (see
903 deflateSetDictionary). For raw inflate, this function can be called at any
904 time to set the dictionary. If the provided dictionary is smaller than the
905 window and there is already data in the window, then the provided dictionary
906 will amend what's there. The application must insure that the dictionary
907 that was used for compression is provided.
908
909 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
910 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
911 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
912 expected one (incorrect Adler-32 value). inflateSetDictionary does not
913 perform any decompression: this will be done by subsequent calls of
914 inflate().
915*/
916
917ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
918 Bytef *dictionary,
919 uInt *dictLength))
920 __API_AVAILABLE(macos(10.10),ios(8.0));
921/*
922 Returns the sliding dictionary being maintained by inflate. dictLength is
923 set to the number of bytes in the dictionary, and that many bytes are copied
924 to dictionary. dictionary must have enough space, where 32768 bytes is
925 always enough. If inflateGetDictionary() is called with dictionary equal to
926 Z_NULL, then only the dictionary length is returned, and nothing is copied.
927 Similary, if dictLength is Z_NULL, then it is not set.
928
929 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
930 stream state is inconsistent.
931*/
932
933ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
934/*
935 Skips invalid compressed data until a possible full flush point (see above
936 for the description of deflate with Z_FULL_FLUSH) can be found, or until all
937 available input is skipped. No output is provided.
938
939 inflateSync searches for a 00 00 FF FF pattern in the compressed data.
940 All full flush points have this pattern, but not all occurrences of this
941 pattern are full flush points.
942
943 inflateSync returns Z_OK if a possible full flush point has been found,
944 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
945 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
946 In the success case, the application may save the current current value of
947 total_in which indicates where valid compressed data was found. In the
948 error case, the application may repeatedly call inflateSync, providing more
949 input each time, until success or end of the input data.
950*/
951
952ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
953 z_streamp source));
954/*
955 Sets the destination stream as a complete copy of the source stream.
956
957 This function can be useful when randomly accessing a large stream. The
958 first pass through the stream can periodically record the inflate state,
959 allowing restarting inflate at those points when randomly accessing the
960 stream.
961
962 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
963 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
964 (such as zalloc being Z_NULL). msg is left unchanged in both source and
965 destination.
966*/
967
968ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
969/*
970 This function is equivalent to inflateEnd followed by inflateInit,
971 but does not free and reallocate the internal decompression state. The
972 stream will keep attributes that may have been set by inflateInit2.
973
974 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
975 stream state was inconsistent (such as zalloc or state being Z_NULL).
976*/
977
978ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
979 int windowBits))
980 __API_AVAILABLE(macos(10.7),ios(5.0));
981/*
982 This function is the same as inflateReset, but it also permits changing
983 the wrap and window size requests. The windowBits parameter is interpreted
984 the same as it is for inflateInit2. If the window size is changed, then the
985 memory allocated for the window is freed, and the window will be reallocated
986 by inflate() if needed.
987
988 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
989 stream state was inconsistent (such as zalloc or state being Z_NULL), or if
990 the windowBits parameter is invalid.
991*/
992
993ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
994 int bits,
995 int value));
996/*
997 This function inserts bits in the inflate input stream. The intent is
998 that this function is used to start inflating at a bit position in the
999 middle of a byte. The provided bits will be used before any bytes are used
1000 from next_in. This function should only be used with raw inflate, and
1001 should be used before the first inflate() call after inflateInit2() or
1002 inflateReset(). bits must be less than or equal to 16, and that many of the
1003 least significant bits of value will be inserted in the input.
1004
1005 If bits is negative, then the input stream bit buffer is emptied. Then
1006 inflatePrime() can be called again to put bits in the buffer. This is used
1007 to clear out bits leftover after feeding inflate a block description prior
1008 to feeding inflate codes.
1009
1010 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
1011 stream state was inconsistent.
1012*/
1013
1014ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm))
1015 __API_AVAILABLE(macos(10.7),ios(5.0));
1016/*
1017 This function returns two values, one in the lower 16 bits of the return
1018 value, and the other in the remaining upper bits, obtained by shifting the
1019 return value down 16 bits. If the upper value is -1 and the lower value is
1020 zero, then inflate() is currently decoding information outside of a block.
1021 If the upper value is -1 and the lower value is non-zero, then inflate is in
1022 the middle of a stored block, with the lower value equaling the number of
1023 bytes from the input remaining to copy. If the upper value is not -1, then
1024 it is the number of bits back from the current bit position in the input of
1025 the code (literal or length/distance pair) currently being processed. In
1026 that case the lower value is the number of bytes already emitted for that
1027 code.
1028
1029 A code is being processed if inflate is waiting for more input to complete
1030 decoding of the code, or if it has completed decoding but is waiting for
1031 more output space to write the literal or match data.
1032
1033 inflateMark() is used to mark locations in the input data for random
1034 access, which may be at bit positions, and to note those cases where the
1035 output of a code may span boundaries of random access blocks. The current
1036 location in the input stream can be determined from avail_in and data_type
1037 as noted in the description for the Z_BLOCK flush parameter for inflate.
1038
1039 inflateMark returns the value noted above, or -65536 if the provided
1040 source stream state was inconsistent.
1041*/
1042
1043ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
1044 gz_headerp head));
1045/*
1046 inflateGetHeader() requests that gzip header information be stored in the
1047 provided gz_header structure. inflateGetHeader() may be called after
1048 inflateInit2() or inflateReset(), and before the first call of inflate().
1049 As inflate() processes the gzip stream, head->done is zero until the header
1050 is completed, at which time head->done is set to one. If a zlib stream is
1051 being decoded, then head->done is set to -1 to indicate that there will be
1052 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
1053 used to force inflate() to return immediately after header processing is
1054 complete and before any actual data is decompressed.
1055
1056 The text, time, xflags, and os fields are filled in with the gzip header
1057 contents. hcrc is set to true if there is a header CRC. (The header CRC
1058 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
1059 contains the maximum number of bytes to write to extra. Once done is true,
1060 extra_len contains the actual extra field length, and extra contains the
1061 extra field, or that field truncated if extra_max is less than extra_len.
1062 If name is not Z_NULL, then up to name_max characters are written there,
1063 terminated with a zero unless the length is greater than name_max. If
1064 comment is not Z_NULL, then up to comm_max characters are written there,
1065 terminated with a zero unless the length is greater than comm_max. When any
1066 of extra, name, or comment are not Z_NULL and the respective field is not
1067 present in the header, then that field is set to Z_NULL to signal its
1068 absence. This allows the use of deflateSetHeader() with the returned
1069 structure to duplicate the header. However if those fields are set to
1070 allocated memory, then the application will need to save those pointers
1071 elsewhere so that they can be eventually freed.
1072
1073 If inflateGetHeader is not used, then the header information is simply
1074 discarded. The header is always checked for validity, including the header
1075 CRC if present. inflateReset() will reset the process to discard the header
1076 information. The application would need to call inflateGetHeader() again to
1077 retrieve the header from the next gzip stream.
1078
1079 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1080 stream state was inconsistent.
1081*/
1082
1083/*
1084ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1085 unsigned char FAR *window));
1086
1087 Initialize the internal stream state for decompression using inflateBack()
1088 calls. The fields zalloc, zfree and opaque in strm must be initialized
1089 before the call. If zalloc and zfree are Z_NULL, then the default library-
1090 derived memory allocation routines are used. windowBits is the base two
1091 logarithm of the window size, in the range 8..15. window is a caller
1092 supplied buffer of that size. Except for special applications where it is
1093 assured that deflate was used with small window sizes, windowBits must be 15
1094 and a 32K byte window must be supplied to be able to decompress general
1095 deflate streams.
1096
1097 See inflateBack() for the usage of these routines.
1098
1099 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1100 the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1101 allocated, or Z_VERSION_ERROR if the version of the library does not match
1102 the version of the header file.
1103*/
1104
1105typedef unsigned (*in_func) OF((void FAR *,
1106 z_const unsigned char FAR * FAR *));
1107typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1108
1109ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1110 in_func in, void FAR *in_desc,
1111 out_func out, void FAR *out_desc));
1112/*
1113 inflateBack() does a raw inflate with a single call using a call-back
1114 interface for input and output. This is potentially more efficient than
1115 inflate() for file i/o applications, in that it avoids copying between the
1116 output and the sliding window by simply making the window itself the output
1117 buffer. inflate() can be faster on modern CPUs when used with large
1118 buffers. inflateBack() trusts the application to not change the output
1119 buffer passed by the output function, at least until inflateBack() returns.
1120
1121 inflateBackInit() must be called first to allocate the internal state
1122 and to initialize the state with the user-provided window buffer.
1123 inflateBack() may then be used multiple times to inflate a complete, raw
1124 deflate stream with each call. inflateBackEnd() is then called to free the
1125 allocated state.
1126
1127 A raw deflate stream is one with no zlib or gzip header or trailer.
1128 This routine would normally be used in a utility that reads zip or gzip
1129 files and writes out uncompressed files. The utility would decode the
1130 header and process the trailer on its own, hence this routine expects only
1131 the raw deflate stream to decompress. This is different from the default
1132 behavior of inflate(), which expects a zlib header and trailer around the
1133 deflate stream.
1134
1135 inflateBack() uses two subroutines supplied by the caller that are then
1136 called by inflateBack() for input and output. inflateBack() calls those
1137 routines until it reads a complete deflate stream and writes out all of the
1138 uncompressed data, or until it encounters an error. The function's
1139 parameters and return types are defined above in the in_func and out_func
1140 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1141 number of bytes of provided input, and a pointer to that input in buf. If
1142 there is no input available, in() must return zero -- buf is ignored in that
1143 case -- and inflateBack() will return a buffer error. inflateBack() will
1144 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
1145 out() should return zero on success, or non-zero on failure. If out()
1146 returns non-zero, inflateBack() will return with an error. Neither in() nor
1147 out() are permitted to change the contents of the window provided to
1148 inflateBackInit(), which is also the buffer that out() uses to write from.
1149 The length written by out() will be at most the window size. Any non-zero
1150 amount of input may be provided by in().
1151
1152 For convenience, inflateBack() can be provided input on the first call by
1153 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1154 in() will be called. Therefore strm->next_in must be initialized before
1155 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1156 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1157 must also be initialized, and then if strm->avail_in is not zero, input will
1158 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1159
1160 The in_desc and out_desc parameters of inflateBack() is passed as the
1161 first parameter of in() and out() respectively when they are called. These
1162 descriptors can be optionally used to pass any information that the caller-
1163 supplied in() and out() functions need to do their job.
1164
1165 On return, inflateBack() will set strm->next_in and strm->avail_in to
1166 pass back any unused input that was provided by the last in() call. The
1167 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1168 if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1169 in the deflate stream (in which case strm->msg is set to indicate the nature
1170 of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1171 In the case of Z_BUF_ERROR, an input or output error can be distinguished
1172 using strm->next_in which will be Z_NULL only if in() returned an error. If
1173 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1174 non-zero. (in() will always be called before out(), so strm->next_in is
1175 assured to be defined if out() returns non-zero.) Note that inflateBack()
1176 cannot return Z_OK.
1177*/
1178
1179ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1180/*
1181 All memory allocated by inflateBackInit() is freed.
1182
1183 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1184 state was inconsistent.
1185*/
1186
1187ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1188/* Return flags indicating compile-time options.
1189
1190 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1191 1.0: size of uInt
1192 3.2: size of uLong
1193 5.4: size of voidpf (pointer)
1194 7.6: size of z_off_t
1195
1196 Compiler, assembler, and debug options:
1197 8: ZLIB_DEBUG
1198 9: ASMV or ASMINF -- use ASM code
1199 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1200 11: 0 (reserved)
1201
1202 One-time table building (smaller code, but not thread-safe if true):
1203 12: BUILDFIXED -- build static block decoding tables when needed
1204 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1205 14,15: 0 (reserved)
1206
1207 Library content (indicates missing functionality):
1208 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1209 deflate code when not needed)
1210 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1211 and decode gzip streams (to avoid linking crc code)
1212 18-19: 0 (reserved)
1213
1214 Operation variations (changes in library functionality):
1215 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1216 21: FASTEST -- deflate algorithm with only one, lowest compression level
1217 22,23: 0 (reserved)
1218
1219 The sprintf variant used by gzprintf (zero is best):
1220 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1221 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1222 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1223
1224 Remainder:
1225 27-31: 0 (reserved)
1226 */
1227
1228#ifndef Z_SOLO
1229
1230 /* utility functions */
1231
1232/*
1233 The following utility functions are implemented on top of the basic
1234 stream-oriented functions. To simplify the interface, some default options
1235 are assumed (compression level and memory usage, standard memory allocation
1236 functions). The source code of these utility functions can be modified if
1237 you need special options.
1238*/
1239
1240ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1241 const Bytef *source, uLong sourceLen));
1242/*
1243 Compresses the source buffer into the destination buffer. sourceLen is
1244 the byte length of the source buffer. Upon entry, destLen is the total size
1245 of the destination buffer, which must be at least the value returned by
1246 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1247 compressed data. compress() is equivalent to compress2() with a level
1248 parameter of Z_DEFAULT_COMPRESSION.
1249
1250 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1251 enough memory, Z_BUF_ERROR if there was not enough room in the output
1252 buffer.
1253*/
1254
1255ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1256 const Bytef *source, uLong sourceLen,
1257 int level));
1258/*
1259 Compresses the source buffer into the destination buffer. The level
1260 parameter has the same meaning as in deflateInit. sourceLen is the byte
1261 length of the source buffer. Upon entry, destLen is the total size of the
1262 destination buffer, which must be at least the value returned by
1263 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1264 compressed data.
1265
1266 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1267 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1268 Z_STREAM_ERROR if the level parameter is invalid.
1269*/
1270
1271ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1272/*
1273 compressBound() returns an upper bound on the compressed size after
1274 compress() or compress2() on sourceLen bytes. It would be used before a
1275 compress() or compress2() call to allocate the destination buffer.
1276*/
1277
1278ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1279 const Bytef *source, uLong sourceLen));
1280/*
1281 Decompresses the source buffer into the destination buffer. sourceLen is
1282 the byte length of the source buffer. Upon entry, destLen is the total size
1283 of the destination buffer, which must be large enough to hold the entire
1284 uncompressed data. (The size of the uncompressed data must have been saved
1285 previously by the compressor and transmitted to the decompressor by some
1286 mechanism outside the scope of this compression library.) Upon exit, destLen
1287 is the actual size of the uncompressed data.
1288
1289 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1290 enough memory, Z_BUF_ERROR if there was not enough room in the output
1291 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1292 the case where there is not enough room, uncompress() will fill the output
1293 buffer with the uncompressed data up to that point.
1294*/
1295
1296ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen,
1297 const Bytef *source, uLong *sourceLen))
1298 __API_AVAILABLE(macos(10.13),ios(11.0));
1299/*
1300 Same as uncompress, except that sourceLen is a pointer, where the
1301 length of the source is *sourceLen. On return, *sourceLen is the number of
1302 source bytes consumed.
1303*/
1304
1305 /* gzip file access functions */
1306
1307/*
1308 This library supports reading and writing files in gzip (.gz) format with
1309 an interface similar to that of stdio, using the functions that start with
1310 "gz". The gzip format is different from the zlib format. gzip is a gzip
1311 wrapper, documented in RFC 1952, wrapped around a deflate stream.
1312*/
1313
1314typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1315
1316/*
1317ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1318
1319 Open the gzip (.gz) file at path for reading and decompressing, or
1320 compressing and writing. The mode parameter is as in fopen ("rb" or "wb")
1321 but can also include a compression level ("wb9") or a strategy: 'f' for
1322 filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h",
1323 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression
1324 as in "wb9F". (See the description of deflateInit2 for more information
1325 about the strategy parameter.) 'T' will request transparent writing or
1326 appending with no compression and not using the gzip format.
1327
1328 "a" can be used instead of "w" to request that the gzip stream that will
1329 be written be appended to the file. "+" will result in an error, since
1330 reading and writing to the same gzip file is not supported. The addition of
1331 "x" when writing will create the file exclusively, which fails if the file
1332 already exists. On systems that support it, the addition of "e" when
1333 reading or writing will set the flag to close the file on an execve() call.
1334
1335 These functions, as well as gzip, will read and decode a sequence of gzip
1336 streams in a file. The append function of gzopen() can be used to create
1337 such a file. (Also see gzflush() for another way to do this.) When
1338 appending, gzopen does not test whether the file begins with a gzip stream,
1339 nor does it look for the end of the gzip streams to begin appending. gzopen
1340 will simply append a gzip stream to the existing file.
1341
1342 gzopen can be used to read a file which is not in gzip format; in this
1343 case gzread will directly read from the file without decompression. When
1344 reading, this will be detected automatically by looking for the magic two-
1345 byte gzip header.
1346
1347 gzopen returns NULL if the file could not be opened, if there was
1348 insufficient memory to allocate the gzFile state, or if an invalid mode was
1349 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1350 errno can be checked to determine if the reason gzopen failed was that the
1351 file could not be opened.
1352*/
1353
1354ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1355/*
1356 Associate a gzFile with the file descriptor fd. File descriptors are
1357 obtained from calls like open, dup, creat, pipe or fileno (if the file has
1358 been previously opened with fopen). The mode parameter is as in gzopen.
1359
1360 The next call of gzclose on the returned gzFile will also close the file
1361 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1362 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1363 mode);. The duplicated descriptor should be saved to avoid a leak, since
1364 gzdopen does not close fd if it fails. If you are using fileno() to get the
1365 file descriptor from a FILE *, then you will have to use dup() to avoid
1366 double-close()ing the file descriptor. Both gzclose() and fclose() will
1367 close the associated file descriptor, so they need to have different file
1368 descriptors.
1369
1370 gzdopen returns NULL if there was insufficient memory to allocate the
1371 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1372 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1373 used until the next gz* read, write, seek, or close operation, so gzdopen
1374 will not detect if fd is invalid (unless fd is -1).
1375*/
1376
1377ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size))
1378 __API_AVAILABLE(macos(10.7),ios(5.0));
1379/*
1380 Set the internal buffer size used by this library's functions for file to
1381 size. The default buffer size is 8192 bytes. This function must be called
1382 after gzopen() or gzdopen(), and before any other calls that read or write
1383 the file. The buffer memory allocation is always deferred to the first read
1384 or write. Three times that size in buffer space is allocated. A larger
1385 buffer size of, for example, 64K or 128K bytes will noticeably increase the
1386 speed of decompression (reading).
1387
1388 The new buffer size also affects the maximum length for gzprintf().
1389
1390 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1391 too late.
1392*/
1393
1394ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1395/*
1396 Dynamically update the compression level and strategy for file. See the
1397 description of deflateInit2 for the meaning of these parameters. Previously
1398 provided data is flushed before applying the parameter changes.
1399
1400 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
1401 opened for writing, Z_ERRNO if there is an error writing the flushed data,
1402 or Z_MEM_ERROR if there is a memory allocation error.
1403*/
1404
1405ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1406/*
1407 Read and decompress up to len uncompressed bytes from file into buf. If
1408 the input file is not in gzip format, gzread copies the given number of
1409 bytes into the buffer directly from the file.
1410
1411 After reaching the end of a gzip stream in the input, gzread will continue
1412 to read, looking for another gzip stream. Any number of gzip streams may be
1413 concatenated in the input file, and will all be decompressed by gzread().
1414 If something other than a gzip stream is encountered after a gzip stream,
1415 that remaining trailing garbage is ignored (and no error is returned).
1416
1417 gzread can be used to read a gzip file that is being concurrently written.
1418 Upon reaching the end of the input, gzread will return with the available
1419 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1420 gzclearerr can be used to clear the end of file indicator in order to permit
1421 gzread to be tried again. Z_OK indicates that a gzip stream was completed
1422 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1423 middle of a gzip stream. Note that gzread does not return -1 in the event
1424 of an incomplete gzip stream. This error is deferred until gzclose(), which
1425 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1426 stream. Alternatively, gzerror can be used before gzclose to detect this
1427 case.
1428
1429 gzread returns the number of uncompressed bytes actually read, less than
1430 len for end of file, or -1 for error. If len is too large to fit in an int,
1431 then nothing is read, -1 is returned, and the error state is set to
1432 Z_STREAM_ERROR.
1433*/
1434
1435ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems,
1436 gzFile file))
1437 __API_AVAILABLE(macos(10.13),ios(11.0));
1438/*
1439 Read and decompress up to nitems items of size size from file into buf,
1440 otherwise operating as gzread() does. This duplicates the interface of
1441 stdio's fread(), with size_t request and return types. If the library
1442 defines size_t, then z_size_t is identical to size_t. If not, then z_size_t
1443 is an unsigned integer type that can contain a pointer.
1444
1445 gzfread() returns the number of full items read of size size, or zero if
1446 the end of the file was reached and a full item could not be read, or if
1447 there was an error. gzerror() must be consulted if zero is returned in
1448 order to determine if there was an error. If the multiplication of size and
1449 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing
1450 is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
1451
1452 In the event that the end of file is reached and only a partial item is
1453 available at the end, i.e. the remaining uncompressed data length is not a
1454 multiple of size, then the final partial item is nevetheless read into buf
1455 and the end-of-file flag is set. The length of the partial item read is not
1456 provided, but could be inferred from the result of gztell(). This behavior
1457 is the same as the behavior of fread() implementations in common libraries,
1458 but it prevents the direct use of gzfread() to read a concurrently written
1459 file, reseting and retrying on end-of-file, when size is not 1.
1460*/
1461
1462ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1463 voidpc buf, unsigned len));
1464/*
1465 Compress and write the len uncompressed bytes at buf to file. gzwrite
1466 returns the number of uncompressed bytes written or 0 in case of error.
1467*/
1468
1469ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
1470 z_size_t nitems, gzFile file))
1471 __API_AVAILABLE(macos(10.13),ios(11.0));
1472/*
1473 Compress and write nitems items of size size from buf to file, duplicating
1474 the interface of stdio's fwrite(), with size_t request and return types. If
1475 the library defines size_t, then z_size_t is identical to size_t. If not,
1476 then z_size_t is an unsigned integer type that can contain a pointer.
1477
1478 gzfwrite() returns the number of full items written of size size, or zero
1479 if there was an error. If the multiplication of size and nitems overflows,
1480 i.e. the product does not fit in a z_size_t, then nothing is written, zero
1481 is returned, and the error state is set to Z_STREAM_ERROR.
1482*/
1483
1484ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1485/*
1486 Convert, format, compress, and write the arguments (...) to file under
1487 control of the string format, as in fprintf. gzprintf returns the number of
1488 uncompressed bytes actually written, or a negative zlib error code in case
1489 of error. The number of uncompressed bytes written is limited to 8191, or
1490 one less than the buffer size given to gzbuffer(). The caller should assure
1491 that this limit is not exceeded. If it is exceeded, then gzprintf() will
1492 return an error (0) with nothing written. In this case, there may also be a
1493 buffer overflow with unpredictable consequences, which is possible only if
1494 zlib was compiled with the insecure functions sprintf() or vsprintf(),
1495 because the secure snprintf() or vsnprintf() functions were not available.
1496 This can be determined using zlibCompileFlags().
1497*/
1498
1499ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1500/*
1501 Compress and write the given null-terminated string s to file, excluding
1502 the terminating null character.
1503
1504 gzputs returns the number of characters written, or -1 in case of error.
1505*/
1506
1507ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1508/*
1509 Read and decompress bytes from file into buf, until len-1 characters are
1510 read, or until a newline character is read and transferred to buf, or an
1511 end-of-file condition is encountered. If any characters are read or if len
1512 is one, the string is terminated with a null character. If no characters
1513 are read due to an end-of-file or len is less than one, then the buffer is
1514 left untouched.
1515
1516 gzgets returns buf which is a null-terminated string, or it returns NULL
1517 for end-of-file or in case of error. If there was an error, the contents at
1518 buf are indeterminate.
1519*/
1520
1521ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1522/*
1523 Compress and write c, converted to an unsigned char, into file. gzputc
1524 returns the value that was written, or -1 in case of error.
1525*/
1526
1527ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1528/*
1529 Read and decompress one byte from file. gzgetc returns this byte or -1
1530 in case of end of file or error. This is implemented as a macro for speed.
1531 As such, it does not do all of the checking the other functions do. I.e.
1532 it does not check to see if file is NULL, nor whether the structure file
1533 points to has been clobbered or not.
1534*/
1535
1536ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1537/*
1538 Push c back onto the stream for file to be read as the first character on
1539 the next read. At least one character of push-back is always allowed.
1540 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1541 fail if c is -1, and may fail if a character has been pushed but not read
1542 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1543 output buffer size of pushed characters is allowed. (See gzbuffer above.)
1544 The pushed character will be discarded if the stream is repositioned with
1545 gzseek() or gzrewind().
1546*/
1547
1548ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1549/*
1550 Flush all pending output to file. The parameter flush is as in the
1551 deflate() function. The return value is the zlib error number (see function
1552 gzerror below). gzflush is only permitted when writing.
1553
1554 If the flush parameter is Z_FINISH, the remaining data is written and the
1555 gzip stream is completed in the output. If gzwrite() is called again, a new
1556 gzip stream will be started in the output. gzread() is able to read such
1557 concatenated gzip streams.
1558
1559 gzflush should be called only when strictly necessary because it will
1560 degrade compression if called too often.
1561*/
1562
1563/*
1564ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1565 z_off_t offset, int whence));
1566
1567 Set the starting position to offset relative to whence for the next gzread
1568 or gzwrite on file. The offset represents a number of bytes in the
1569 uncompressed data stream. The whence parameter is defined as in lseek(2);
1570 the value SEEK_END is not supported.
1571
1572 If the file is opened for reading, this function is emulated but can be
1573 extremely slow. If the file is opened for writing, only forward seeks are
1574 supported; gzseek then compresses a sequence of zeroes up to the new
1575 starting position.
1576
1577 gzseek returns the resulting offset location as measured in bytes from
1578 the beginning of the uncompressed stream, or -1 in case of error, in
1579 particular if the file is opened for writing and the new starting position
1580 would be before the current position.
1581*/
1582
1583ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1584/*
1585 Rewind file. This function is supported only for reading.
1586
1587 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET).
1588*/
1589
1590/*
1591ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1592
1593 Return the starting position for the next gzread or gzwrite on file.
1594 This position represents a number of bytes in the uncompressed data stream,
1595 and is zero when starting, even if appending or reading a gzip stream from
1596 the middle of a file using gzdopen().
1597
1598 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1599*/
1600
1601/*
1602ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1603
1604 Return the current compressed (actual) read or write offset of file. This
1605 offset includes the count of bytes that precede the gzip stream, for example
1606 when appending or when using gzdopen() for reading. When reading, the
1607 offset does not include as yet unused buffered input. This information can
1608 be used for a progress indicator. On error, gzoffset() returns -1.
1609*/
1610
1611ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1612/*
1613 Return true (1) if the end-of-file indicator for file has been set while
1614 reading, false (0) otherwise. Note that the end-of-file indicator is set
1615 only if the read tried to go past the end of the input, but came up short.
1616 Therefore, just like feof(), gzeof() may return false even if there is no
1617 more data to read, in the event that the last read request was for the exact
1618 number of bytes remaining in the input file. This will happen if the input
1619 file size is an exact multiple of the buffer size.
1620
1621 If gzeof() returns true, then the read functions will return no more data,
1622 unless the end-of-file indicator is reset by gzclearerr() and the input file
1623 has grown since the previous end of file was detected.
1624*/
1625
1626ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1627/*
1628 Return true (1) if file is being copied directly while reading, or false
1629 (0) if file is a gzip stream being decompressed.
1630
1631 If the input file is empty, gzdirect() will return true, since the input
1632 does not contain a gzip stream.
1633
1634 If gzdirect() is used immediately after gzopen() or gzdopen() it will
1635 cause buffers to be allocated to allow reading the file to determine if it
1636 is a gzip file. Therefore if gzbuffer() is used, it should be called before
1637 gzdirect().
1638
1639 When writing, gzdirect() returns true (1) if transparent writing was
1640 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1641 gzdirect() is not needed when writing. Transparent writing must be
1642 explicitly requested, so the application already knows the answer. When
1643 linking statically, using gzdirect() will include all of the zlib code for
1644 gzip file reading and decompression, which may not be desired.)
1645*/
1646
1647ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1648/*
1649 Flush all pending output for file, if necessary, close file and
1650 deallocate the (de)compression state. Note that once file is closed, you
1651 cannot call gzerror with file, since its structures have been deallocated.
1652 gzclose must not be called more than once on the same file, just as free
1653 must not be called more than once on the same allocation.
1654
1655 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1656 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1657 last read ended in the middle of a gzip stream, or Z_OK on success.
1658*/
1659
1660ZEXTERN int ZEXPORT gzclose_r OF((gzFile file))
1661 __API_AVAILABLE(macos(10.7),ios(5.0));
1662ZEXTERN int ZEXPORT gzclose_w OF((gzFile file))
1663 __API_AVAILABLE(macos(10.7),ios(5.0));
1664/*
1665 Same as gzclose(), but gzclose_r() is only for use when reading, and
1666 gzclose_w() is only for use when writing or appending. The advantage to
1667 using these instead of gzclose() is that they avoid linking in zlib
1668 compression or decompression code that is not used when only reading or only
1669 writing respectively. If gzclose() is used, then both compression and
1670 decompression code will be included the application when linking to a static
1671 zlib library.
1672
1673 Because Mac OS X doesn't use a static zlib library, these routine are of
1674 no value for Mac OS X-only applications, and gzclose() is recommended
1675 instead.
1676*/
1677
1678ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1679/*
1680 Return the error message for the last error which occurred on file.
1681 errnum is set to zlib error number. If an error occurred in the file system
1682 and not in the compression library, errnum is set to Z_ERRNO and the
1683 application may consult errno to get the exact error code.
1684
1685 The application must not modify the returned string. Future calls to
1686 this function may invalidate the previously returned string. If file is
1687 closed, then the string previously returned by gzerror will no longer be
1688 available.
1689
1690 gzerror() should be used to distinguish errors from end-of-file for those
1691 functions above that do not distinguish those cases in their return values.
1692*/
1693
1694ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1695/*
1696 Clear the error and end-of-file flags for file. This is analogous to the
1697 clearerr() function in stdio. This is useful for continuing to read a gzip
1698 file that is being written concurrently.
1699*/
1700
1701#endif /* !Z_SOLO */
1702
1703 /* checksum functions */
1704
1705/*
1706 These functions are not related to compression but are exported
1707 anyway because they might be useful in applications using the compression
1708 library.
1709*/
1710
1711ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1712/*
1713 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1714 return the updated checksum. An Adler-32 value is in the range of a 32-bit
1715 unsigned integer. If buf is Z_NULL, this function returns the required
1716 initial value for the checksum.
1717
1718 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1719 much faster.
1720
1721 Usage example:
1722
1723 uLong adler = adler32(0L, Z_NULL, 0);
1724
1725 while (read_buffer(buffer, length) != EOF) {
1726 adler = adler32(adler, buffer, length);
1727 }
1728 if (adler != original_adler) error();
1729*/
1730
1731ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf,
1732 z_size_t len))
1733 __API_AVAILABLE(macos(10.13),ios(11.0));
1734/*
1735 Same as adler32(), but with a size_t length.
1736*/
1737
1738/*
1739ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1740 z_off_t len2));
1741
1742 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1743 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1744 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1745 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1746 that the z_off_t type (like off_t) is a signed integer. If len2 is
1747 negative, the result has no meaning or utility.
1748*/
1749
1750ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1751/*
1752 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1753 updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer.
1754 If buf is Z_NULL, this function returns the required initial value for the
1755 crc. Pre- and post-conditioning (one's complement) is performed within this
1756 function so it shouldn't be done by the application.
1757
1758 Usage example:
1759
1760 uLong crc = crc32(0L, Z_NULL, 0);
1761
1762 while (read_buffer(buffer, length) != EOF) {
1763 crc = crc32(crc, buffer, length);
1764 }
1765 if (crc != original_crc) error();
1766*/
1767
1768ZEXTERN uLong ZEXPORT crc32_z OF((uLong crc, const Bytef *buf,
1769 z_size_t len))
1770 __API_AVAILABLE(macos(10.13),ios(11.0));
1771/*
1772 Same as crc32(), but with a size_t length.
1773*/
1774
1775/*
1776ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1777
1778 Combine two CRC-32 check values into one. For two sequences of bytes,
1779 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1780 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1781 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1782 len2.
1783*/
1784
1785/*
1786ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t len2));
1787
1788 Return the operator corresponding to length len2, to be used with
1789 crc32_combine_op().
1790*/
1791
1792ZEXTERN uLong ZEXPORT crc32_combine_op OF((uLong crc1, uLong crc2, uLong op))
1793 __API_AVAILABLE(macos(14.0),ios(17.0));
1794/*
1795 Give the same result as crc32_combine(), using op in place of len2. op is
1796 is generated from len2 by crc32_combine_gen(). This will be faster than
1797 crc32_combine() if the generated op is used more than once.
1798*/
1799
1800
1801 /* various hacks, don't look :) */
1802
1803/* deflateInit and inflateInit are macros to allow checking the zlib version
1804 * and the compiler's view of z_stream:
1805 */
1806ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1807 const char *version, int stream_size));
1808ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1809 const char *version, int stream_size));
1810ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1811 int windowBits, int memLevel,
1812 int strategy, const char *version,
1813 int stream_size));
1814ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1815 const char *version, int stream_size));
1816ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1817 unsigned char FAR *window,
1818 const char *version,
1819 int stream_size));
1820#ifdef Z_PREFIX_SET
1821# define z_deflateInit(strm, level) \
1822 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1823# define z_inflateInit(strm) \
1824 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1825# define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1826 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1827 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1828# define z_inflateInit2(strm, windowBits) \
1829 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1830 (int)sizeof(z_stream))
1831# define z_inflateBackInit(strm, windowBits, window) \
1832 inflateBackInit_((strm), (windowBits), (window), \
1833 ZLIB_VERSION, (int)sizeof(z_stream))
1834#else
1835# define deflateInit(strm, level) \
1836 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1837# define inflateInit(strm) \
1838 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1839# define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1840 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1841 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1842# define inflateInit2(strm, windowBits) \
1843 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1844 (int)sizeof(z_stream))
1845# define inflateBackInit(strm, windowBits, window) \
1846 inflateBackInit_((strm), (windowBits), (window), \
1847 ZLIB_VERSION, (int)sizeof(z_stream))
1848#endif
1849
1850#ifndef Z_SOLO
1851
1852/* gzgetc() macro and its supporting function and exposed data structure. Note
1853 * that the real internal state is much larger than the exposed structure.
1854 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1855 * user should not mess with these exposed elements, since their names or
1856 * behavior could change in the future, perhaps even capriciously. They can
1857 * only be used by the gzgetc() macro. You have been warned.
1858 */
1859struct gzFile_s {
1860 unsigned have;
1861 unsigned char *next;
1862 z_off64_t pos;
1863};
1864ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file))
1865 __API_AVAILABLE(macos(10.10),ios(8.0)); /* backward compatibility */
1866#ifdef Z_PREFIX_SET
1867# undef z_gzgetc
1868# define z_gzgetc(g) \
1869 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1870#else
1871# define gzgetc(g) \
1872 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1873#endif
1874
1875/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1876 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1877 * both are true, the application gets the *64 functions, and the regular
1878 * functions are changed to 64 bits) -- in case these are set on systems
1879 * without large file support, _LFS64_LARGEFILE must also be true
1880 */
1881#ifdef Z_LARGE64
1882 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1883 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1884 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1885 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1886 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1887 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1888 ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off64_t));
1889#endif
1890
1891#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1892# ifdef Z_PREFIX_SET
1893# define z_gzopen z_gzopen64
1894# define z_gzseek z_gzseek64
1895# define z_gztell z_gztell64
1896# define z_gzoffset z_gzoffset64
1897# define z_adler32_combine z_adler32_combine64
1898# define z_crc32_combine z_crc32_combine64
1899# define z_crc32_combine_gen z_crc32_combine_gen64
1900# else
1901# define gzopen gzopen64
1902# define gzseek gzseek64
1903# define gztell gztell64
1904# define gzoffset gzoffset64
1905# define adler32_combine adler32_combine64
1906# define crc32_combine crc32_combine64
1907# define crc32_combine_gen crc32_combine_gen64
1908# endif
1909# ifndef Z_LARGE64
1910 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1911 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1912 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1913 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1914 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1915 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1916 ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off_t));
1917# endif
1918#else
1919 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1920 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1921 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1922 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile))
1923 __API_AVAILABLE(macos(10.7),ios(5.0));
1924 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1925 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1926 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t))
1927 __API_AVAILABLE(macos(14.0),ios(17.0));
1928#endif
1929
1930#else /* Z_SOLO */
1931 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1932 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1933 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t));
1934
1935#endif /* !Z_SOLO */
1936
1937/* undocumented functions */
1938ZEXTERN const char * ZEXPORT zError OF((int));
1939ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1940ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1941ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int))
1942 __API_AVAILABLE(macos(10.7),ios(5.0));
1943ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int))
1944 __API_AVAILABLE(macos(10.13),ios(11.0));
1945ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF ((z_streamp))
1946 __API_AVAILABLE(macos(10.13),ios(11.0));
1947ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp))
1948 __API_AVAILABLE(macos(10.10),ios(8.0));
1949ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp))
1950 __API_AVAILABLE(macos(10.10),ios(8.0));
1951#if defined(_WIN32) && !defined(Z_SOLO)
1952ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1953 const char *mode));
1954#endif
1955#if defined(STDC) || defined(Z_HAVE_STDARG_H)
1956# ifndef Z_SOLO
1957ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1958 const char *format,
1959 va_list va))
1960 __API_AVAILABLE(macos(10.10),ios(8.0));
1961# endif
1962#endif
1963
1964#ifdef __cplusplus
1965}
1966#endif
1967
1968#ifndef __APPLE__
1969#undef __API_AVAILABLE
1970#endif /* !__APPLE__ */
1971
1972#endif /* ZLIB_H */