1	/* zlib.h -- interface of the 'zlib' general purpose compression library
2	version 1.2.11, January 15th, 2017
3
4	Copyright (C) 1995-2017 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 __cplusplus
37	extern "C" {
38	#endif
39
40	#define ZLIB_VERSION "1.2.11"
41	#define ZLIB_VERNUM 0x12b0
42	#define ZLIB_VER_MAJOR 1
43	#define ZLIB_VER_MINOR 2
44	#define ZLIB_VER_REVISION 11
45	#define ZLIB_VER_SUBREVISION 0
46
47	/*
48	The 'zlib' compression library provides in-memory compression and
49	decompression functions, including integrity checks of the uncompressed data.
50	This version of the library supports only one compression method (deflation)
51	but other algorithms will be added later and will have the same stream
52	interface.
53
54	Compression can be done in a single step if the buffers are large enough,
55	or can be done by repeated calls of the compression function. In the latter
56	case, the application must provide more input and/or consume the output
57	(providing more output space) before each call.
58
59	The compressed data format used by default by the in-memory functions is
60	the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
61	around a deflate stream, which is itself documented in RFC 1951.
62
63	The library also supports reading and writing files in gzip (.gz) format
64	with an interface similar to that of stdio using the functions that start
65	with "gz". The gzip format is different from the zlib format. gzip is a
66	gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
67
68	This library can optionally read and write gzip and raw deflate streams in
69	memory as well.
70
71	The zlib format was designed to be compact and fast for use in memory
72	and on communications channels. The gzip format was designed for single-
73	file compression on file systems, has a larger header than zlib to maintain
74	directory information, and uses a different, slower check method than zlib.
75
76	The library does not install any signal handler. The decoder checks
77	the consistency of the compressed data, so the library should never crash
78	even in the case of corrupted input.
79	*/
80
81	typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
82	typedef void (*free_func) OF((voidpf opaque, voidpf address));
83
84	struct internal_state;
85
86	typedef struct z_stream_s {
87	z_const Bytef *next_in; /* next input byte */
88	uInt avail_in; /* number of bytes available at next_in */
89	uLong total_in; /* total number of input bytes read so far */
90
91	Bytef *next_out; /* next output byte will go here */
92	uInt avail_out; /* remaining free space at next_out */
93	uLong total_out; /* total number of bytes output so far */
94
95	z_const char *msg; /* last error message, NULL if no error */
96	struct internal_state FAR *state; /* not visible by applications */
97
98	alloc_func zalloc; /* used to allocate the internal state */
99	free_func zfree; /* used to free the internal state */
100	voidpf opaque; /* private data object passed to zalloc and zfree */
101
102	int data_type; /* best guess about the data type: binary or text
103	for deflate, or the decoding state for inflate */
104	uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */
105	uLong reserved; /* reserved for future use */
106	} z_stream;
107
108	typedef z_stream FAR *z_streamp;
109
110	/*
111	gzip header information passed to and from zlib routines. See RFC 1952
112	for more details on the meanings of these fields.
113	*/
114	typedef struct gz_header_s {
115	int text; /* true if compressed data believed to be text */
116	uLong time; /* modification time */
117	int xflags; /* extra flags (not used when writing a gzip file) */
118	int os; /* operating system */
119	Bytef *extra; /* pointer to extra field or Z_NULL if none */
120	uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
121	uInt extra_max; /* space at extra (only when reading header) */
122	Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
123	uInt name_max; /* space at name (only when reading header) */
124	Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
125	uInt comm_max; /* space at comment (only when reading header) */
126	int hcrc; /* true if there was or will be a header crc */
127	int done; /* true when done reading gzip header (not used
128	when writing a gzip file) */
129	} gz_header;
130
131	typedef gz_header FAR *gz_headerp;
132
133	/*
134	The application must update next_in and avail_in when avail_in has dropped
135	to zero. It must update next_out and avail_out when avail_out has dropped
136	to zero. The application must initialize zalloc, zfree and opaque before
137	calling the init function. All other fields are set by the compression
138	library and must not be updated by the application.
139
140	The opaque value provided by the application will be passed as the first
141	parameter for calls of zalloc and zfree. This can be useful for custom
142	memory management. The compression library attaches no meaning to the
143	opaque value.
144
145	zalloc must return Z_NULL if there is not enough memory for the object.
146	If zlib is used in a multi-threaded application, zalloc and zfree must be
147	thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
148	Z_NULL on entry to the initialization function, they are set to internal
149	routines that use the standard library functions malloc() and free().
150
151	On 16-bit systems, the functions zalloc and zfree must be able to allocate
152	exactly 65536 bytes, but will not be required to allocate more than this if
153	the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
154	returned by zalloc for objects of exactly 65536 bytes *must* have their
155	offset normalized to zero. The default allocation function provided by this
156	library ensures this (see zutil.c). To reduce memory requirements and avoid
157	any allocation of 64K objects, at the expense of compression ratio, compile
158	the library with -DMAX_WBITS=14 (see zconf.h).
159
160	The fields total_in and total_out can be used for statistics or progress
161	reports. After compression, total_in holds the total size of the
162	uncompressed data and may be saved for use by the decompressor (particularly
163	if the decompressor wants to decompress everything in a single step).
164	*/
165
166	/* constants */
167
168	#define Z_NO_FLUSH 0
169	#define Z_PARTIAL_FLUSH 1
170	#define Z_SYNC_FLUSH 2
171	#define Z_FULL_FLUSH 3
172	#define Z_FINISH 4
173	#define Z_BLOCK 5
174	#define Z_TREES 6
175	/* Allowed flush values; see deflate() and inflate() below for details */
176
177	#define Z_OK 0
178	#define Z_STREAM_END 1
179	#define Z_NEED_DICT 2
180	#define Z_ERRNO (-1)
181	#define Z_STREAM_ERROR (-2)
182	#define Z_DATA_ERROR (-3)
183	#define Z_MEM_ERROR (-4)
184	#define Z_BUF_ERROR (-5)
185	#define Z_VERSION_ERROR (-6)
186	/* Return codes for the compression/decompression functions. Negative values
187	* are errors, positive values are used for special but normal events.
188	*/
189
190	#define Z_NO_COMPRESSION 0
191	#define Z_BEST_SPEED 1
192	#define Z_BEST_COMPRESSION 9
193	#define Z_DEFAULT_COMPRESSION (-1)
194	/* compression levels */
195
196	#define Z_FILTERED 1
197	#define Z_HUFFMAN_ONLY 2
198	#define Z_RLE 3
199	#define Z_FIXED 4
200	#define Z_DEFAULT_STRATEGY 0
201	/* compression strategy; see deflateInit2() below for details */
202
203	#define Z_BINARY 0
204	#define Z_TEXT 1
205	#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
206	#define Z_UNKNOWN 2
207	/* Possible values of the data_type field for deflate() */
208
209	#define Z_DEFLATED 8
210	/* The deflate compression method (the only one supported in this version) */
211
212	#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
213
214	#define zlib_version zlibVersion()
215	/* for compatibility with versions < 1.0.2 */
216
217
218	/* basic functions */
219
220	ZEXTERN const char * ZEXPORT zlibVersion OF((void));
221	/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
222	If the first character differs, the library code actually used is not
223	compatible with the zlib.h header file used by the application. This check
224	is automatically made by deflateInit and inflateInit.
225	*/
226
227	/*
228	ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
229
230	Initializes the internal stream state for compression. The fields
231	zalloc, zfree and opaque must be initialized before by the caller. If
232	zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
233	allocation functions.
234
235	The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
236	1 gives best speed, 9 gives best compression, 0 gives no compression at all
237	(the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
238	requests a default compromise between speed and compression (currently
239	equivalent to level 6).
240
241	deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
242	memory, Z_STREAM_ERROR if level is not a valid compression level, or
243	Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
244	with the version assumed by the caller (ZLIB_VERSION). msg is set to null
245	if there is no error message. deflateInit does not perform any compression:
246	this will be done by deflate().
247	*/
248
249
250	ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
251	/*
252	deflate compresses as much data as possible, and stops when the input
253	buffer becomes empty or the output buffer becomes full. It may introduce
254	some output latency (reading input without producing any output) except when
255	forced to flush.
256
257	The detailed semantics are as follows. deflate performs one or both of the
258	following actions:
259
260	- Compress more input starting at next_in and update next_in and avail_in
261	accordingly. If not all input can be processed (because there is not
262	enough room in the output buffer), next_in and avail_in are updated and
263	processing will resume at this point for the next call of deflate().
264
265	- Generate more output starting at next_out and update next_out and avail_out
266	accordingly. This action is forced if the parameter flush is non zero.
267	Forcing flush frequently degrades the compression ratio, so this parameter
268	should be set only when necessary. Some output may be provided even if
269	flush is zero.
270
271	Before the call of deflate(), the application should ensure that at least
272	one of the actions is possible, by providing more input and/or consuming more
273	output, and updating avail_in or avail_out accordingly; avail_out should
274	never be zero before the call. The application can consume the compressed
275	output when it wants, for example when the output buffer is full (avail_out
276	== 0), or after each call of deflate(). If deflate returns Z_OK and with
277	zero avail_out, it must be called again after making room in the output
278	buffer because there might be more output pending. See deflatePending(),
279	which can be used if desired to determine whether or not there is more ouput
280	in that case.
281
282	Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
283	decide how much data to accumulate before producing output, in order to
284	maximize compression.
285
286	If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
287	flushed to the output buffer and the output is aligned on a byte boundary, so
288	that the decompressor can get all input data available so far. (In
289	particular avail_in is zero after the call if enough output space has been
290	provided before the call.) Flushing may degrade compression for some
291	compression algorithms and so it should be used only when necessary. This
292	completes the current deflate block and follows it with an empty stored block
293	that is three bits plus filler bits to the next byte, followed by four bytes
294	(00 00 ff ff).
295
296	If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
297	output buffer, but the output is not aligned to a byte boundary. All of the
298	input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
299	This completes the current deflate block and follows it with an empty fixed
300	codes block that is 10 bits long. This assures that enough bytes are output
301	in order for the decompressor to finish the block before the empty fixed
302	codes block.
303
304	If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
305	for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
306	seven bits of the current block are held to be written as the next byte after
307	the next deflate block is completed. In this case, the decompressor may not
308	be provided enough bits at this point in order to complete decompression of
309	the data provided so far to the compressor. It may need to wait for the next
310	block to be emitted. This is for advanced applications that need to control
311	the emission of deflate blocks.
312
313	If flush is set to Z_FULL_FLUSH, all output is flushed as with
314	Z_SYNC_FLUSH, and the compression state is reset so that decompression can
315	restart from this point if previous compressed data has been damaged or if
316	random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
317	compression.
318
319	If deflate returns with avail_out == 0, this function must be called again
320	with the same value of the flush parameter and more output space (updated
321	avail_out), until the flush is complete (deflate returns with non-zero
322	avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
323	avail_out is greater than six to avoid repeated flush markers due to
324	avail_out == 0 on return.
325
326	If the parameter flush is set to Z_FINISH, pending input is processed,
327	pending output is flushed and deflate returns with Z_STREAM_END if there was
328	enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this
329	function must be called again with Z_FINISH and more output space (updated
330	avail_out) but no more input data, until it returns with Z_STREAM_END or an
331	error. After deflate has returned Z_STREAM_END, the only possible operations
332	on the stream are deflateReset or deflateEnd.
333
334	Z_FINISH can be used in the first deflate call after deflateInit if all the
335	compression is to be done in a single step. In order to complete in one
336	call, avail_out must be at least the value returned by deflateBound (see
337	below). Then deflate is guaranteed to return Z_STREAM_END. If not enough
338	output space is provided, deflate will not return Z_STREAM_END, and it must
339	be called again as described above.
340
341	deflate() sets strm->adler to the Adler-32 checksum of all input read
342	so far (that is, total_in bytes). If a gzip stream is being generated, then
343	strm->adler will be the CRC-32 checksum of the input read so far. (See
344	deflateInit2 below.)
345
346	deflate() may update strm->data_type if it can make a good guess about
347	the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is
348	considered binary. This field is only for information purposes and does not
349	affect the compression algorithm in any manner.
350
351	deflate() returns Z_OK if some progress has been made (more input
352	processed or more output produced), Z_STREAM_END if all input has been
353	consumed and all output has been produced (only when flush is set to
354	Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
355	if next_in or next_out was Z_NULL or the state was inadvertently written over
356	by the application), or Z_BUF_ERROR if no progress is possible (for example
357	avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
358	deflate() can be called again with more input and more output space to
359	continue compressing.
360	*/
361
362
363	ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
364	/*
365	All dynamically allocated data structures for this stream are freed.
366	This function discards any unprocessed input and does not flush any pending
367	output.
368
369	deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
370	stream state was inconsistent, Z_DATA_ERROR if the stream was freed
371	prematurely (some input or output was discarded). In the error case, msg
372	may be set but then points to a static string (which must not be
373	deallocated).
374	*/
375
376
377	/*
378	ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
379
380	Initializes the internal stream state for decompression. The fields
381	next_in, avail_in, zalloc, zfree and opaque must be initialized before by
382	the caller. In the current version of inflate, the provided input is not
383	read or consumed. The allocation of a sliding window will be deferred to
384	the first call of inflate (if the decompression does not complete on the
385	first call). If zalloc and zfree are set to Z_NULL, inflateInit updates
386	them to use default allocation functions.
387
388	inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
389	memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
390	version assumed by the caller, or Z_STREAM_ERROR if the parameters are
391	invalid, such as a null pointer to the structure. msg is set to null if
392	there is no error message. inflateInit does not perform any decompression.
393	Actual decompression will be done by inflate(). So next_in, and avail_in,
394	next_out, and avail_out are unused and unchanged. The current
395	implementation of inflateInit() does not process any header information --
396	that is deferred until inflate() is called.
397	*/
398
399
400	ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
401	/*
402	inflate decompresses as much data as possible, and stops when the input
403	buffer becomes empty or the output buffer becomes full. It may introduce
404	some output latency (reading input without producing any output) except when
405	forced to flush.
406
407	The detailed semantics are as follows. inflate performs one or both of the
408	following actions:
409
410	- Decompress more input starting at next_in and update next_in and avail_in
411	accordingly. If not all input can be processed (because there is not
412	enough room in the output buffer), then next_in and avail_in are updated
413	accordingly, and processing will resume at this point for the next call of
414	inflate().
415
416	- Generate more output starting at next_out and update next_out and avail_out
417	accordingly. inflate() provides as much output as possible, until there is
418	no more input data or no more space in the output buffer (see below about
419	the flush parameter).
420
421	Before the call of inflate(), the application should ensure that at least
422	one of the actions is possible, by providing more input and/or consuming more
423	output, and updating the next_* and avail_* values accordingly. If the
424	caller of inflate() does not provide both available input and available
425	output space, it is possible that there will be no progress made. The
426	application can consume the uncompressed output when it wants, for example
427	when the output buffer is full (avail_out == 0), or after each call of
428	inflate(). If inflate returns Z_OK and with zero avail_out, it must be
429	called again after making room in the output buffer because there might be
430	more output pending.
431
432	The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
433	Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
434	output as possible to the output buffer. Z_BLOCK requests that inflate()
435	stop if and when it gets to the next deflate block boundary. When decoding
436	the zlib or gzip format, this will cause inflate() to return immediately
437	after the header and before the first block. When doing a raw inflate,
438	inflate() will go ahead and process the first block, and will return when it
439	gets to the end of that block, or when it runs out of data.
440
441	The Z_BLOCK option assists in appending to or combining deflate streams.
442	To assist in this, on return inflate() always sets strm->data_type to the
443	number of unused bits in the last byte taken from strm->next_in, plus 64 if
444	inflate() is currently decoding the last block in the deflate stream, plus
445	128 if inflate() returned immediately after decoding an end-of-block code or
446	decoding the complete header up to just before the first byte of the deflate
447	stream. The end-of-block will not be indicated until all of the uncompressed
448	data from that block has been written to strm->next_out. The number of
449	unused bits may in general be greater than seven, except when bit 7 of
450	data_type is set, in which case the number of unused bits will be less than
451	eight. data_type is set as noted here every time inflate() returns for all
452	flush options, and so can be used to determine the amount of currently
453	consumed input in bits.
454
455	The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
456	end of each deflate block header is reached, before any actual data in that
457	block is decoded. This allows the caller to determine the length of the
458	deflate block header for later use in random access within a deflate block.
459	256 is added to the value of strm->data_type when inflate() returns
460	immediately after reaching the end of the deflate block header.
461
462	inflate() should normally be called until it returns Z_STREAM_END or an
463	error. However if all decompression is to be performed in a single step (a
464	single call of inflate), the parameter flush should be set to Z_FINISH. In
465	this case all pending input is processed and all pending output is flushed;
466	avail_out must be large enough to hold all of the uncompressed data for the
467	operation to complete. (The size of the uncompressed data may have been
468	saved by the compressor for this purpose.) The use of Z_FINISH is not
469	required to perform an inflation in one step. However it may be used to
470	inform inflate that a faster approach can be used for the single inflate()
471	call. Z_FINISH also informs inflate to not maintain a sliding window if the
472	stream completes, which reduces inflate's memory footprint. If the stream
473	does not complete, either because not all of the stream is provided or not
474	enough output space is provided, then a sliding window will be allocated and
475	inflate() can be called again to continue the operation as if Z_NO_FLUSH had
476	been used.
477
478	In this implementation, inflate() always flushes as much output as
479	possible to the output buffer, and always uses the faster approach on the
480	first call. So the effects of the flush parameter in this implementation are
481	on the return value of inflate() as noted below, when inflate() returns early
482	when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
483	memory for a sliding window when Z_FINISH is used.
484
485	If a preset dictionary is needed after this call (see inflateSetDictionary
486	below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
487	chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
488	strm->adler to the Adler-32 checksum of all output produced so far (that is,
489	total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
490	below. At the end of the stream, inflate() checks that its computed Adler-32
491	checksum is equal to that saved by the compressor and returns Z_STREAM_END
492	only if the checksum is correct.
493
494	inflate() can decompress and check either zlib-wrapped or gzip-wrapped
495	deflate data. The header type is detected automatically, if requested when
496	initializing with inflateInit2(). Any information contained in the gzip
497	header is not retained unless inflateGetHeader() is used. When processing
498	gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
499	produced so far. The CRC-32 is checked against the gzip trailer, as is the
500	uncompressed length, modulo 2^32.
501
502	inflate() returns Z_OK if some progress has been made (more input processed
503	or more output produced), Z_STREAM_END if the end of the compressed data has
504	been reached and all uncompressed output has been produced, Z_NEED_DICT if a
505	preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
506	corrupted (input stream not conforming to the zlib format or incorrect check
507	value, in which case strm->msg points to a string with a more specific
508	error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
509	next_in or next_out was Z_NULL, or the state was inadvertently written over
510	by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
511	if no progress was possible or if there was not enough room in the output
512	buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
513	inflate() can be called again with more input and more output space to
514	continue decompressing. If Z_DATA_ERROR is returned, the application may
515	then call inflateSync() to look for a good compression block if a partial
516	recovery of the data is to be attempted.
517	*/
518
519
520	ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
521	/*
522	All dynamically allocated data structures for this stream are freed.
523	This function discards any unprocessed input and does not flush any pending
524	output.
525
526	inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
527	was inconsistent.
528	*/
529
530
531	/* Advanced functions */
532
533	/*
534	The following functions are needed only in some special applications.
535	*/
536
537	/*
538	ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
539	int level,
540	int method,
541	int windowBits,
542	int memLevel,
543	int strategy));
544
545	This is another version of deflateInit with more compression options. The
546	fields next_in, zalloc, zfree and opaque must be initialized before by the
547	caller.
548
549	The method parameter is the compression method. It must be Z_DEFLATED in
550	this version of the library.
551
552	The windowBits parameter is the base two logarithm of the window size
553	(the size of the history buffer). It should be in the range 8..15 for this
554	version of the library. Larger values of this parameter result in better
555	compression at the expense of memory usage. The default value is 15 if
556	deflateInit is used instead.
557
558	For the current implementation of deflate(), a windowBits value of 8 (a
559	window size of 256 bytes) is not supported. As a result, a request for 8
560	will result in 9 (a 512-byte window). In that case, providing 8 to
561	inflateInit2() will result in an error when the zlib header with 9 is
562	checked against the initialization of inflate(). The remedy is to not use 8
563	with deflateInit2() with this initialization, or at least in that case use 9
564	with inflateInit2().
565
566	windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
567	determines the window size. deflate() will then generate raw deflate data
568	with no zlib header or trailer, and will not compute a check value.
569
570	windowBits can also be greater than 15 for optional gzip encoding. Add
571	16 to windowBits to write a simple gzip header and trailer around the
572	compressed data instead of a zlib wrapper. The gzip header will have no
573	file name, no extra data, no comment, no modification time (set to zero), no
574	header crc, and the operating system will be set to the appropriate value,
575	if the operating system was determined at compile time. If a gzip stream is
576	being written, strm->adler is a CRC-32 instead of an Adler-32.
577
578	For raw deflate or gzip encoding, a request for a 256-byte window is
579	rejected as invalid, since only the zlib header provides a means of
580	transmitting the window size to the decompressor.
581
582	The memLevel parameter specifies how much memory should be allocated
583	for the internal compression state. memLevel=1 uses minimum memory but is
584	slow and reduces compression ratio; memLevel=9 uses maximum memory for
585	optimal speed. The default value is 8. See zconf.h for total memory usage
586	as a function of windowBits and memLevel.
587
588	The strategy parameter is used to tune the compression algorithm. Use the
589	value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
590	filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
591	string match), or Z_RLE to limit match distances to one (run-length
592	encoding). Filtered data consists mostly of small values with a somewhat
593	random distribution. In this case, the compression algorithm is tuned to
594	compress them better. The effect of Z_FILTERED is to force more Huffman
595	coding and less string matching; it is somewhat intermediate between
596	Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
597	fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
598	strategy parameter only affects the compression ratio but not the
599	correctness of the compressed output even if it is not set appropriately.
600	Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
601	decoder for special applications.
602
603	deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
604	memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
605	method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
606	incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
607	set to null if there is no error message. deflateInit2 does not perform any
608	compression: this will be done by deflate().
609	*/
610
611	ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
612	const Bytef *dictionary,
613	uInt dictLength));
614	/*
615	Initializes the compression dictionary from the given byte sequence
616	without producing any compressed output. When using the zlib format, this
617	function must be called immediately after deflateInit, deflateInit2 or
618	deflateReset, and before any call of deflate. When doing raw deflate, this
619	function must be called either before any call of deflate, or immediately
620	after the completion of a deflate block, i.e. after all input has been
621	consumed and all output has been delivered when using any of the flush
622	options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
623	compressor and decompressor must use exactly the same dictionary (see
624	inflateSetDictionary).
625
626	The dictionary should consist of strings (byte sequences) that are likely
627	to be encountered later in the data to be compressed, with the most commonly
628	used strings preferably put towards the end of the dictionary. Using a
629	dictionary is most useful when the data to be compressed is short and can be
630	predicted with good accuracy; the data can then be compressed better than
631	with the default empty dictionary.
632
633	Depending on the size of the compression data structures selected by
634	deflateInit or deflateInit2, a part of the dictionary may in effect be
635	discarded, for example if the dictionary is larger than the window size
636	provided in deflateInit or deflateInit2. Thus the strings most likely to be
637	useful should be put at the end of the dictionary, not at the front. In
638	addition, the current implementation of deflate will use at most the window
639	size minus 262 bytes of the provided dictionary.
640
641	Upon return of this function, strm->adler is set to the Adler-32 value
642	of the dictionary; the decompressor may later use this value to determine
643	which dictionary has been used by the compressor. (The Adler-32 value
644	applies to the whole dictionary even if only a subset of the dictionary is
645	actually used by the compressor.) If a raw deflate was requested, then the
646	Adler-32 value is not computed and strm->adler is not set.
647
648	deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
649	parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
650	inconsistent (for example if deflate has already been called for this stream
651	or if not at a block boundary for raw deflate). deflateSetDictionary does
652	not perform any compression: this will be done by deflate().
653	*/
654
655	ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm,
656	Bytef *dictionary,
657	uInt *dictLength));
658	/*
659	Returns the sliding dictionary being maintained by deflate. dictLength is
660	set to the number of bytes in the dictionary, and that many bytes are copied
661	to dictionary. dictionary must have enough space, where 32768 bytes is
662	always enough. If deflateGetDictionary() is called with dictionary equal to
663	Z_NULL, then only the dictionary length is returned, and nothing is copied.
664	Similary, if dictLength is Z_NULL, then it is not set.
665
666	deflateGetDictionary() may return a length less than the window size, even
667	when more than the window size in input has been provided. It may return up
668	to 258 bytes less in that case, due to how zlib's implementation of deflate
669	manages the sliding window and lookahead for matches, where matches can be
670	up to 258 bytes long. If the application needs the last window-size bytes of
671	input, then that would need to be saved by the application outside of zlib.
672
673	deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
674	stream state is inconsistent.
675	*/
676
677	ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
678	z_streamp source));
679	/*
680	Sets the destination stream as a complete copy of the source stream.
681
682	This function can be useful when several compression strategies will be
683	tried, for example when there are several ways of pre-processing the input
684	data with a filter. The streams that will be discarded should then be freed
685	by calling deflateEnd. Note that deflateCopy duplicates the internal
686	compression state which can be quite large, so this strategy is slow and can
687	consume lots of memory.
688
689	deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
690	enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
691	(such as zalloc being Z_NULL). msg is left unchanged in both source and
692	destination.
693	*/
694
695	ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
696	/*
697	This function is equivalent to deflateEnd followed by deflateInit, but
698	does not free and reallocate the internal compression state. The stream
699	will leave the compression level and any other attributes that may have been
700	set unchanged.
701
702	deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
703	stream state was inconsistent (such as zalloc or state being Z_NULL).
704	*/
705
706	ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
707	int level,
708	int strategy));
709	/*
710	Dynamically update the compression level and compression strategy. The
711	interpretation of level and strategy is as in deflateInit2(). This can be
712	used to switch between compression and straight copy of the input data, or
713	to switch to a different kind of input data requiring a different strategy.
714	If the compression approach (which is a function of the level) or the
715	strategy is changed, and if there have been any deflate() calls since the
716	state was initialized or reset, then the input available so far is
717	compressed with the old level and strategy using deflate(strm, Z_BLOCK).
718	There are three approaches for the compression levels 0, 1..3, and 4..9
719	respectively. The new level and strategy will take effect at the next call
720	of deflate().
721
722	If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
723	not have enough output space to complete, then the parameter change will not
724	take effect. In this case, deflateParams() can be called again with the
725	same parameters and more output space to try again.
726
727	In order to assure a change in the parameters on the first try, the
728	deflate stream should be flushed using deflate() with Z_BLOCK or other flush
729	request until strm.avail_out is not zero, before calling deflateParams().
730	Then no more input data should be provided before the deflateParams() call.
731	If this is done, the old level and strategy will be applied to the data
732	compressed before deflateParams(), and the new level and strategy will be
733	applied to the the data compressed after deflateParams().
734
735	deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
736	state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
737	there was not enough output space to complete the compression of the
738	available input data before a change in the strategy or approach. Note that
739	in the case of a Z_BUF_ERROR, the parameters are not changed. A return
740	value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
741	retried with more output space.
742	*/
743
744	ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
745	int good_length,
746	int max_lazy,
747	int nice_length,
748	int max_chain));
749	/*
750	Fine tune deflate's internal compression parameters. This should only be
751	used by someone who understands the algorithm used by zlib's deflate for
752	searching for the best matching string, and even then only by the most
753	fanatic optimizer trying to squeeze out the last compressed bit for their
754	specific input data. Read the deflate.c source code for the meaning of the
755	max_lazy, good_length, nice_length, and max_chain parameters.
756
757	deflateTune() can be called after deflateInit() or deflateInit2(), and
758	returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
759	*/
760
761	ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
762	uLong sourceLen));
763	/*
764	deflateBound() returns an upper bound on the compressed size after
765	deflation of sourceLen bytes. It must be called after deflateInit() or
766	deflateInit2(), and after deflateSetHeader(), if used. This would be used
767	to allocate an output buffer for deflation in a single pass, and so would be
768	called before deflate(). If that first deflate() call is provided the
769	sourceLen input bytes, an output buffer allocated to the size returned by
770	deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
771	to return Z_STREAM_END. Note that it is possible for the compressed size to
772	be larger than the value returned by deflateBound() if flush options other
773	than Z_FINISH or Z_NO_FLUSH are used.
774	*/
775
776	ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
777	unsigned *pending,
778	int *bits));
779	/*
780	deflatePending() returns the number of bytes and bits of output that have
781	been generated, but not yet provided in the available output. The bytes not
782	provided would be due to the available output space having being consumed.
783	The number of bits of output not provided are between 0 and 7, where they
784	await more bits to join them in order to fill out a full byte. If pending
785	or bits are Z_NULL, then those values are not set.
786
787	deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
788	stream state was inconsistent.
789	*/
790
791	ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
792	int bits,
793	int value));
794	/*
795	deflatePrime() inserts bits in the deflate output stream. The intent
796	is that this function is used to start off the deflate output with the bits
797	leftover from a previous deflate stream when appending to it. As such, this
798	function can only be used for raw deflate, and must be used before the first
799	deflate() call after a deflateInit2() or deflateReset(). bits must be less
800	than or equal to 16, and that many of the least significant bits of value
801	will be inserted in the output.
802
803	deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
804	room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
805	source stream state was inconsistent.
806	*/
807
808	ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
809	gz_headerp head));
810	/*
811	deflateSetHeader() provides gzip header information for when a gzip
812	stream is requested by deflateInit2(). deflateSetHeader() may be called
813	after deflateInit2() or deflateReset() and before the first call of
814	deflate(). The text, time, os, extra field, name, and comment information
815	in the provided gz_header structure are written to the gzip header (xflag is
816	ignored -- the extra flags are set according to the compression level). The
817	caller must assure that, if not Z_NULL, name and comment are terminated with
818	a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
819	available there. If hcrc is true, a gzip header crc is included. Note that
820	the current versions of the command-line version of gzip (up through version
821	1.3.x) do not support header crc's, and will report that it is a "multi-part
822	gzip file" and give up.
823
824	If deflateSetHeader is not used, the default gzip header has text false,
825	the time set to zero, and os set to 255, with no extra, name, or comment
826	fields. The gzip header is returned to the default state by deflateReset().
827
828	deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
829	stream state was inconsistent.
830	*/
831
832	/*
833	ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
834	int windowBits));
835
836	This is another version of inflateInit with an extra parameter. The
837	fields next_in, avail_in, zalloc, zfree and opaque must be initialized
838	before by the caller.
839
840	The windowBits parameter is the base two logarithm of the maximum window
841	size (the size of the history buffer). It should be in the range 8..15 for
842	this version of the library. The default value is 15 if inflateInit is used
843	instead. windowBits must be greater than or equal to the windowBits value
844	provided to deflateInit2() while compressing, or it must be equal to 15 if
845	deflateInit2() was not used. If a compressed stream with a larger window
846	size is given as input, inflate() will return with the error code
847	Z_DATA_ERROR instead of trying to allocate a larger window.
848
849	windowBits can also be zero to request that inflate use the window size in
850	the zlib header of the compressed stream.
851
852	windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
853	determines the window size. inflate() will then process raw deflate data,
854	not looking for a zlib or gzip header, not generating a check value, and not
855	looking for any check values for comparison at the end of the stream. This
856	is for use with other formats that use the deflate compressed data format
857	such as zip. Those formats provide their own check values. If a custom
858	format is developed using the raw deflate format for compressed data, it is
859	recommended that a check value such as an Adler-32 or a CRC-32 be applied to
860	the uncompressed data as is done in the zlib, gzip, and zip formats. For
861	most applications, the zlib format should be used as is. Note that comments
862	above on the use in deflateInit2() applies to the magnitude of windowBits.
863
864	windowBits can also be greater than 15 for optional gzip decoding. Add
865	32 to windowBits to enable zlib and gzip decoding with automatic header
866	detection, or add 16 to decode only the gzip format (the zlib format will
867	return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
868	CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see
869	below), inflate() will not automatically decode concatenated gzip streams.
870	inflate() will return Z_STREAM_END at the end of the gzip stream. The state
871	would need to be reset to continue decoding a subsequent gzip stream.
872
873	inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
874	memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
875	version assumed by the caller, or Z_STREAM_ERROR if the parameters are
876	invalid, such as a null pointer to the structure. msg is set to null if
877	there is no error message. inflateInit2 does not perform any decompression
878	apart from possibly reading the zlib header if present: actual decompression
879	will be done by inflate(). (So next_in and avail_in may be modified, but
880	next_out and avail_out are unused and unchanged.) The current implementation
881	of inflateInit2() does not process any header information -- that is
882	deferred until inflate() is called.
883	*/
884
885	ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
886	const Bytef *dictionary,
887	uInt dictLength));
888	/*
889	Initializes the decompression dictionary from the given uncompressed byte
890	sequence. This function must be called immediately after a call of inflate,
891	if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
892	can be determined from the Adler-32 value returned by that call of inflate.
893	The compressor and decompressor must use exactly the same dictionary (see
894	deflateSetDictionary). For raw inflate, this function can be called at any
895	time to set the dictionary. If the provided dictionary is smaller than the
896	window and there is already data in the window, then the provided dictionary
897	will amend what's there. The application must insure that the dictionary
898	that was used for compression is provided.
899
900	inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
901	parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
902	inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
903	expected one (incorrect Adler-32 value). inflateSetDictionary does not
904	perform any decompression: this will be done by subsequent calls of
905	inflate().
906	*/
907
908	ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
909	Bytef *dictionary,
910	uInt *dictLength));
911	/*
912	Returns the sliding dictionary being maintained by inflate. dictLength is
913	set to the number of bytes in the dictionary, and that many bytes are copied
914	to dictionary. dictionary must have enough space, where 32768 bytes is
915	always enough. If inflateGetDictionary() is called with dictionary equal to
916	Z_NULL, then only the dictionary length is returned, and nothing is copied.
917	Similary, if dictLength is Z_NULL, then it is not set.
918
919	inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
920	stream state is inconsistent.
921	*/
922
923	ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
924	/*
925	Skips invalid compressed data until a possible full flush point (see above
926	for the description of deflate with Z_FULL_FLUSH) can be found, or until all
927	available input is skipped. No output is provided.
928
929	inflateSync searches for a 00 00 FF FF pattern in the compressed data.
930	All full flush points have this pattern, but not all occurrences of this
931	pattern are full flush points.
932
933	inflateSync returns Z_OK if a possible full flush point has been found,
934	Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
935	has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
936	In the success case, the application may save the current current value of
937	total_in which indicates where valid compressed data was found. In the
938	error case, the application may repeatedly call inflateSync, providing more
939	input each time, until success or end of the input data.
940	*/
941
942	ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
943	z_streamp source));
944	/*
945	Sets the destination stream as a complete copy of the source stream.
946
947	This function can be useful when randomly accessing a large stream. The
948	first pass through the stream can periodically record the inflate state,
949	allowing restarting inflate at those points when randomly accessing the
950	stream.
951
952	inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
953	enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
954	(such as zalloc being Z_NULL). msg is left unchanged in both source and
955	destination.
956	*/
957
958	ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
959	/*
960	This function is equivalent to inflateEnd followed by inflateInit,
961	but does not free and reallocate the internal decompression state. The
962	stream will keep attributes that may have been set by inflateInit2.
963
964	inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
965	stream state was inconsistent (such as zalloc or state being Z_NULL).
966	*/
967
968	ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
969	int windowBits));
970	/*
971	This function is the same as inflateReset, but it also permits changing
972	the wrap and window size requests. The windowBits parameter is interpreted
973	the same as it is for inflateInit2. If the window size is changed, then the
974	memory allocated for the window is freed, and the window will be reallocated
975	by inflate() if needed.
976
977	inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
978	stream state was inconsistent (such as zalloc or state being Z_NULL), or if
979	the windowBits parameter is invalid.
980	*/
981
982	ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
983	int bits,
984	int value));
985	/*
986	This function inserts bits in the inflate input stream. The intent is
987	that this function is used to start inflating at a bit position in the
988	middle of a byte. The provided bits will be used before any bytes are used
989	from next_in. This function should only be used with raw inflate, and
990	should be used before the first inflate() call after inflateInit2() or
991	inflateReset(). bits must be less than or equal to 16, and that many of the
992	least significant bits of value will be inserted in the input.
993
994	If bits is negative, then the input stream bit buffer is emptied. Then
995	inflatePrime() can be called again to put bits in the buffer. This is used
996	to clear out bits leftover after feeding inflate a block description prior
997	to feeding inflate codes.
998
999	inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
1000	stream state was inconsistent.
1001	*/
1002
1003	ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
1004	/*
1005	This function returns two values, one in the lower 16 bits of the return
1006	value, and the other in the remaining upper bits, obtained by shifting the
1007	return value down 16 bits. If the upper value is -1 and the lower value is
1008	zero, then inflate() is currently decoding information outside of a block.
1009	If the upper value is -1 and the lower value is non-zero, then inflate is in
1010	the middle of a stored block, with the lower value equaling the number of
1011	bytes from the input remaining to copy. If the upper value is not -1, then
1012	it is the number of bits back from the current bit position in the input of
1013	the code (literal or length/distance pair) currently being processed. In
1014	that case the lower value is the number of bytes already emitted for that
1015	code.
1016
1017	A code is being processed if inflate is waiting for more input to complete
1018	decoding of the code, or if it has completed decoding but is waiting for
1019	more output space to write the literal or match data.
1020
1021	inflateMark() is used to mark locations in the input data for random
1022	access, which may be at bit positions, and to note those cases where the
1023	output of a code may span boundaries of random access blocks. The current
1024	location in the input stream can be determined from avail_in and data_type
1025	as noted in the description for the Z_BLOCK flush parameter for inflate.
1026
1027	inflateMark returns the value noted above, or -65536 if the provided
1028	source stream state was inconsistent.
1029	*/
1030
1031	ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
1032	gz_headerp head));
1033	/*
1034	inflateGetHeader() requests that gzip header information be stored in the
1035	provided gz_header structure. inflateGetHeader() may be called after
1036	inflateInit2() or inflateReset(), and before the first call of inflate().
1037	As inflate() processes the gzip stream, head->done is zero until the header
1038	is completed, at which time head->done is set to one. If a zlib stream is
1039	being decoded, then head->done is set to -1 to indicate that there will be
1040	no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
1041	used to force inflate() to return immediately after header processing is
1042	complete and before any actual data is decompressed.
1043
1044	The text, time, xflags, and os fields are filled in with the gzip header
1045	contents. hcrc is set to true if there is a header CRC. (The header CRC
1046	was valid if done is set to one.) If extra is not Z_NULL, then extra_max
1047	contains the maximum number of bytes to write to extra. Once done is true,
1048	extra_len contains the actual extra field length, and extra contains the
1049	extra field, or that field truncated if extra_max is less than extra_len.
1050	If name is not Z_NULL, then up to name_max characters are written there,
1051	terminated with a zero unless the length is greater than name_max. If
1052	comment is not Z_NULL, then up to comm_max characters are written there,
1053	terminated with a zero unless the length is greater than comm_max. When any
1054	of extra, name, or comment are not Z_NULL and the respective field is not
1055	present in the header, then that field is set to Z_NULL to signal its
1056	absence. This allows the use of deflateSetHeader() with the returned
1057	structure to duplicate the header. However if those fields are set to
1058	allocated memory, then the application will need to save those pointers
1059	elsewhere so that they can be eventually freed.
1060
1061	If inflateGetHeader is not used, then the header information is simply
1062	discarded. The header is always checked for validity, including the header
1063	CRC if present. inflateReset() will reset the process to discard the header
1064	information. The application would need to call inflateGetHeader() again to
1065	retrieve the header from the next gzip stream.
1066
1067	inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1068	stream state was inconsistent.
1069	*/
1070
1071	/*
1072	ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1073	unsigned char FAR *window));
1074
1075	Initialize the internal stream state for decompression using inflateBack()
1076	calls. The fields zalloc, zfree and opaque in strm must be initialized
1077	before the call. If zalloc and zfree are Z_NULL, then the default library-
1078	derived memory allocation routines are used. windowBits is the base two
1079	logarithm of the window size, in the range 8..15. window is a caller
1080	supplied buffer of that size. Except for special applications where it is
1081	assured that deflate was used with small window sizes, windowBits must be 15
1082	and a 32K byte window must be supplied to be able to decompress general
1083	deflate streams.
1084
1085	See inflateBack() for the usage of these routines.
1086
1087	inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1088	the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1089	allocated, or Z_VERSION_ERROR if the version of the library does not match
1090	the version of the header file.
1091	*/
1092
1093	typedef unsigned (*in_func) OF((void FAR *,
1094	z_const unsigned char FAR * FAR *));
1095	typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1096
1097	ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1098	in_func in, void FAR *in_desc,
1099	out_func out, void FAR *out_desc));
1100	/*
1101	inflateBack() does a raw inflate with a single call using a call-back
1102	interface for input and output. This is potentially more efficient than
1103	inflate() for file i/o applications, in that it avoids copying between the
1104	output and the sliding window by simply making the window itself the output
1105	buffer. inflate() can be faster on modern CPUs when used with large
1106	buffers. inflateBack() trusts the application to not change the output
1107	buffer passed by the output function, at least until inflateBack() returns.
1108
1109	inflateBackInit() must be called first to allocate the internal state
1110	and to initialize the state with the user-provided window buffer.
1111	inflateBack() may then be used multiple times to inflate a complete, raw
1112	deflate stream with each call. inflateBackEnd() is then called to free the
1113	allocated state.
1114
1115	A raw deflate stream is one with no zlib or gzip header or trailer.
1116	This routine would normally be used in a utility that reads zip or gzip
1117	files and writes out uncompressed files. The utility would decode the
1118	header and process the trailer on its own, hence this routine expects only
1119	the raw deflate stream to decompress. This is different from the default
1120	behavior of inflate(), which expects a zlib header and trailer around the
1121	deflate stream.
1122
1123	inflateBack() uses two subroutines supplied by the caller that are then
1124	called by inflateBack() for input and output. inflateBack() calls those
1125	routines until it reads a complete deflate stream and writes out all of the
1126	uncompressed data, or until it encounters an error. The function's
1127	parameters and return types are defined above in the in_func and out_func
1128	typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1129	number of bytes of provided input, and a pointer to that input in buf. If
1130	there is no input available, in() must return zero -- buf is ignored in that
1131	case -- and inflateBack() will return a buffer error. inflateBack() will
1132	call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
1133	out() should return zero on success, or non-zero on failure. If out()
1134	returns non-zero, inflateBack() will return with an error. Neither in() nor
1135	out() are permitted to change the contents of the window provided to
1136	inflateBackInit(), which is also the buffer that out() uses to write from.
1137	The length written by out() will be at most the window size. Any non-zero
1138	amount of input may be provided by in().
1139
1140	For convenience, inflateBack() can be provided input on the first call by
1141	setting strm->next_in and strm->avail_in. If that input is exhausted, then
1142	in() will be called. Therefore strm->next_in must be initialized before
1143	calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1144	immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1145	must also be initialized, and then if strm->avail_in is not zero, input will
1146	initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1147
1148	The in_desc and out_desc parameters of inflateBack() is passed as the
1149	first parameter of in() and out() respectively when they are called. These
1150	descriptors can be optionally used to pass any information that the caller-
1151	supplied in() and out() functions need to do their job.
1152
1153	On return, inflateBack() will set strm->next_in and strm->avail_in to
1154	pass back any unused input that was provided by the last in() call. The
1155	return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1156	if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1157	in the deflate stream (in which case strm->msg is set to indicate the nature
1158	of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1159	In the case of Z_BUF_ERROR, an input or output error can be distinguished
1160	using strm->next_in which will be Z_NULL only if in() returned an error. If
1161	strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1162	non-zero. (in() will always be called before out(), so strm->next_in is
1163	assured to be defined if out() returns non-zero.) Note that inflateBack()
1164	cannot return Z_OK.
1165	*/
1166
1167	ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1168	/*
1169	All memory allocated by inflateBackInit() is freed.
1170
1171	inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1172	state was inconsistent.
1173	*/
1174
1175	ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1176	/* Return flags indicating compile-time options.
1177
1178	Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1179	1.0: size of uInt
1180	3.2: size of uLong
1181	5.4: size of voidpf (pointer)
1182	7.6: size of z_off_t
1183
1184	Compiler, assembler, and debug options:
1185	8: ZLIB_DEBUG
1186	9: ASMV or ASMINF -- use ASM code
1187	10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1188	11: 0 (reserved)
1189
1190	One-time table building (smaller code, but not thread-safe if true):
1191	12: BUILDFIXED -- build static block decoding tables when needed
1192	13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1193	14,15: 0 (reserved)
1194
1195	Library content (indicates missing functionality):
1196	16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1197	deflate code when not needed)
1198	17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1199	and decode gzip streams (to avoid linking crc code)
1200	18-19: 0 (reserved)
1201
1202	Operation variations (changes in library functionality):
1203	20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1204	21: FASTEST -- deflate algorithm with only one, lowest compression level
1205	22,23: 0 (reserved)
1206
1207	The sprintf variant used by gzprintf (zero is best):
1208	24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1209	25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1210	26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1211
1212	Remainder:
1213	27-31: 0 (reserved)
1214	*/
1215
1216	#ifndef Z_SOLO
1217
1218	/* utility functions */
1219
1220	/*
1221	The following utility functions are implemented on top of the basic
1222	stream-oriented functions. To simplify the interface, some default options
1223	are assumed (compression level and memory usage, standard memory allocation
1224	functions). The source code of these utility functions can be modified if
1225	you need special options.
1226	*/
1227
1228	ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1229	const Bytef *source, uLong sourceLen));
1230	/*
1231	Compresses the source buffer into the destination buffer. sourceLen is
1232	the byte length of the source buffer. Upon entry, destLen is the total size
1233	of the destination buffer, which must be at least the value returned by
1234	compressBound(sourceLen). Upon exit, destLen is the actual size of the
1235	compressed data. compress() is equivalent to compress2() with a level
1236	parameter of Z_DEFAULT_COMPRESSION.
1237
1238	compress returns Z_OK if success, Z_MEM_ERROR if there was not
1239	enough memory, Z_BUF_ERROR if there was not enough room in the output
1240	buffer.
1241	*/
1242
1243	ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1244	const Bytef *source, uLong sourceLen,
1245	int level));
1246	/*
1247	Compresses the source buffer into the destination buffer. The level
1248	parameter has the same meaning as in deflateInit. sourceLen is the byte
1249	length of the source buffer. Upon entry, destLen is the total size of the
1250	destination buffer, which must be at least the value returned by
1251	compressBound(sourceLen). Upon exit, destLen is the actual size of the
1252	compressed data.
1253
1254	compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1255	memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1256	Z_STREAM_ERROR if the level parameter is invalid.
1257	*/
1258
1259	ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1260	/*
1261	compressBound() returns an upper bound on the compressed size after
1262	compress() or compress2() on sourceLen bytes. It would be used before a
1263	compress() or compress2() call to allocate the destination buffer.
1264	*/
1265
1266	ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1267	const Bytef *source, uLong sourceLen));
1268	/*
1269	Decompresses the source buffer into the destination buffer. sourceLen is
1270	the byte length of the source buffer. Upon entry, destLen is the total size
1271	of the destination buffer, which must be large enough to hold the entire
1272	uncompressed data. (The size of the uncompressed data must have been saved
1273	previously by the compressor and transmitted to the decompressor by some
1274	mechanism outside the scope of this compression library.) Upon exit, destLen
1275	is the actual size of the uncompressed data.
1276
1277	uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1278	enough memory, Z_BUF_ERROR if there was not enough room in the output
1279	buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1280	the case where there is not enough room, uncompress() will fill the output
1281	buffer with the uncompressed data up to that point.
1282	*/
1283
1284	ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen,
1285	const Bytef *source, uLong *sourceLen));
1286	/*
1287	Same as uncompress, except that sourceLen is a pointer, where the
1288	length of the source is *sourceLen. On return, *sourceLen is the number of
1289	source bytes consumed.
1290	*/
1291
1292	/* gzip file access functions */
1293
1294	/*
1295	This library supports reading and writing files in gzip (.gz) format with
1296	an interface similar to that of stdio, using the functions that start with
1297	"gz". The gzip format is different from the zlib format. gzip is a gzip
1298	wrapper, documented in RFC 1952, wrapped around a deflate stream.
1299	*/
1300
1301	typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1302
1303	/*
1304	ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1305
1306	Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1307	in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1308	a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1309	compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1310	for fixed code compression as in "wb9F". (See the description of
1311	deflateInit2 for more information about the strategy parameter.) 'T' will
1312	request transparent writing or appending with no compression and not using
1313	the gzip format.
1314
1315	"a" can be used instead of "w" to request that the gzip stream that will
1316	be written be appended to the file. "+" will result in an error, since
1317	reading and writing to the same gzip file is not supported. The addition of
1318	"x" when writing will create the file exclusively, which fails if the file
1319	already exists. On systems that support it, the addition of "e" when
1320	reading or writing will set the flag to close the file on an execve() call.
1321
1322	These functions, as well as gzip, will read and decode a sequence of gzip
1323	streams in a file. The append function of gzopen() can be used to create
1324	such a file. (Also see gzflush() for another way to do this.) When
1325	appending, gzopen does not test whether the file begins with a gzip stream,
1326	nor does it look for the end of the gzip streams to begin appending. gzopen
1327	will simply append a gzip stream to the existing file.
1328
1329	gzopen can be used to read a file which is not in gzip format; in this
1330	case gzread will directly read from the file without decompression. When
1331	reading, this will be detected automatically by looking for the magic two-
1332	byte gzip header.
1333
1334	gzopen returns NULL if the file could not be opened, if there was
1335	insufficient memory to allocate the gzFile state, or if an invalid mode was
1336	specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1337	errno can be checked to determine if the reason gzopen failed was that the
1338	file could not be opened.
1339	*/
1340
1341	ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1342	/*
1343	gzdopen associates a gzFile with the file descriptor fd. File descriptors
1344	are obtained from calls like open, dup, creat, pipe or fileno (if the file
1345	has been previously opened with fopen). The mode parameter is as in gzopen.
1346
1347	The next call of gzclose on the returned gzFile will also close the file
1348	descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1349	fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1350	mode);. The duplicated descriptor should be saved to avoid a leak, since
1351	gzdopen does not close fd if it fails. If you are using fileno() to get the
1352	file descriptor from a FILE *, then you will have to use dup() to avoid
1353	double-close()ing the file descriptor. Both gzclose() and fclose() will
1354	close the associated file descriptor, so they need to have different file
1355	descriptors.
1356
1357	gzdopen returns NULL if there was insufficient memory to allocate the
1358	gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1359	provided, or '+' was provided), or if fd is -1. The file descriptor is not
1360	used until the next gz* read, write, seek, or close operation, so gzdopen
1361	will not detect if fd is invalid (unless fd is -1).
1362	*/
1363
1364	ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1365	/*
1366	Set the internal buffer size used by this library's functions. The
1367	default buffer size is 8192 bytes. This function must be called after
1368	gzopen() or gzdopen(), and before any other calls that read or write the
1369	file. The buffer memory allocation is always deferred to the first read or
1370	write. Three times that size in buffer space is allocated. A larger buffer
1371	size of, for example, 64K or 128K bytes will noticeably increase the speed
1372	of decompression (reading).
1373
1374	The new buffer size also affects the maximum length for gzprintf().
1375
1376	gzbuffer() returns 0 on success, or -1 on failure, such as being called
1377	too late.
1378	*/
1379
1380	ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1381	/*
1382	Dynamically update the compression level or strategy. See the description
1383	of deflateInit2 for the meaning of these parameters. Previously provided
1384	data is flushed before the parameter change.
1385
1386	gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
1387	opened for writing, Z_ERRNO if there is an error writing the flushed data,
1388	or Z_MEM_ERROR if there is a memory allocation error.
1389	*/
1390
1391	ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1392	/*
1393	Reads the given number of uncompressed bytes from the compressed file. If
1394	the input file is not in gzip format, gzread copies the given number of
1395	bytes into the buffer directly from the file.
1396
1397	After reaching the end of a gzip stream in the input, gzread will continue
1398	to read, looking for another gzip stream. Any number of gzip streams may be
1399	concatenated in the input file, and will all be decompressed by gzread().
1400	If something other than a gzip stream is encountered after a gzip stream,
1401	that remaining trailing garbage is ignored (and no error is returned).
1402
1403	gzread can be used to read a gzip file that is being concurrently written.
1404	Upon reaching the end of the input, gzread will return with the available
1405	data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1406	gzclearerr can be used to clear the end of file indicator in order to permit
1407	gzread to be tried again. Z_OK indicates that a gzip stream was completed
1408	on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1409	middle of a gzip stream. Note that gzread does not return -1 in the event
1410	of an incomplete gzip stream. This error is deferred until gzclose(), which
1411	will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1412	stream. Alternatively, gzerror can be used before gzclose to detect this
1413	case.
1414
1415	gzread returns the number of uncompressed bytes actually read, less than
1416	len for end of file, or -1 for error. If len is too large to fit in an int,
1417	then nothing is read, -1 is returned, and the error state is set to
1418	Z_STREAM_ERROR.
1419	*/
1420
1421	ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems,
1422	gzFile file));
1423	/*
1424	Read up to nitems items of size size from file to buf, otherwise operating
1425	as gzread() does. This duplicates the interface of stdio's fread(), with
1426	size_t request and return types. If the library defines size_t, then
1427	z_size_t is identical to size_t. If not, then z_size_t is an unsigned
1428	integer type that can contain a pointer.
1429
1430	gzfread() returns the number of full items read of size size, or zero if
1431	the end of the file was reached and a full item could not be read, or if
1432	there was an error. gzerror() must be consulted if zero is returned in
1433	order to determine if there was an error. If the multiplication of size and
1434	nitems overflows, i.e. the product does not fit in a z_size_t, then nothing
1435	is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
1436
1437	In the event that the end of file is reached and only a partial item is
1438	available at the end, i.e. the remaining uncompressed data length is not a
1439	multiple of size, then the final partial item is nevetheless read into buf
1440	and the end-of-file flag is set. The length of the partial item read is not
1441	provided, but could be inferred from the result of gztell(). This behavior
1442	is the same as the behavior of fread() implementations in common libraries,
1443	but it prevents the direct use of gzfread() to read a concurrently written
1444	file, reseting and retrying on end-of-file, when size is not 1.
1445	*/
1446
1447	ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1448	voidpc buf, unsigned len));
1449	/*
1450	Writes the given number of uncompressed bytes into the compressed file.
1451	gzwrite returns the number of uncompressed bytes written or 0 in case of
1452	error.
1453	*/
1454
1455	ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
1456	z_size_t nitems, gzFile file));
1457	/*
1458	gzfwrite() writes nitems items of size size from buf to file, duplicating
1459	the interface of stdio's fwrite(), with size_t request and return types. If
1460	the library defines size_t, then z_size_t is identical to size_t. If not,
1461	then z_size_t is an unsigned integer type that can contain a pointer.
1462
1463	gzfwrite() returns the number of full items written of size size, or zero
1464	if there was an error. If the multiplication of size and nitems overflows,
1465	i.e. the product does not fit in a z_size_t, then nothing is written, zero
1466	is returned, and the error state is set to Z_STREAM_ERROR.
1467	*/
1468
1469	ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1470	/*
1471	Converts, formats, and writes the arguments to the compressed file under
1472	control of the format string, as in fprintf. gzprintf returns the number of
1473	uncompressed bytes actually written, or a negative zlib error code in case
1474	of error. The number of uncompressed bytes written is limited to 8191, or
1475	one less than the buffer size given to gzbuffer(). The caller should assure
1476	that this limit is not exceeded. If it is exceeded, then gzprintf() will
1477	return an error (0) with nothing written. In this case, there may also be a
1478	buffer overflow with unpredictable consequences, which is possible only if
1479	zlib was compiled with the insecure functions sprintf() or vsprintf()
1480	because the secure snprintf() or vsnprintf() functions were not available.
1481	This can be determined using zlibCompileFlags().
1482	*/
1483
1484	ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1485	/*
1486	Writes the given null-terminated string to the compressed file, excluding
1487	the terminating null character.
1488
1489	gzputs returns the number of characters written, or -1 in case of error.
1490	*/
1491
1492	ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1493	/*
1494	Reads bytes from the compressed file until len-1 characters are read, or a
1495	newline character is read and transferred to buf, or an end-of-file
1496	condition is encountered. If any characters are read or if len == 1, the
1497	string is terminated with a null character. If no characters are read due
1498	to an end-of-file or len < 1, then the buffer is left untouched.
1499
1500	gzgets returns buf which is a null-terminated string, or it returns NULL
1501	for end-of-file or in case of error. If there was an error, the contents at
1502	buf are indeterminate.
1503	*/
1504
1505	ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1506	/*
1507	Writes c, converted to an unsigned char, into the compressed file. gzputc
1508	returns the value that was written, or -1 in case of error.
1509	*/
1510
1511	ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1512	/*
1513	Reads one byte from the compressed file. gzgetc returns this byte or -1
1514	in case of end of file or error. This is implemented as a macro for speed.
1515	As such, it does not do all of the checking the other functions do. I.e.
1516	it does not check to see if file is NULL, nor whether the structure file
1517	points to has been clobbered or not.
1518	*/
1519
1520	ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1521	/*
1522	Push one character back onto the stream to be read as the first character
1523	on the next read. At least one character of push-back is allowed.
1524	gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1525	fail if c is -1, and may fail if a character has been pushed but not read
1526	yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1527	output buffer size of pushed characters is allowed. (See gzbuffer above.)
1528	The pushed character will be discarded if the stream is repositioned with
1529	gzseek() or gzrewind().
1530	*/
1531
1532	ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1533	/*
1534	Flushes all pending output into the compressed file. The parameter flush
1535	is as in the deflate() function. The return value is the zlib error number
1536	(see function gzerror below). gzflush is only permitted when writing.
1537
1538	If the flush parameter is Z_FINISH, the remaining data is written and the
1539	gzip stream is completed in the output. If gzwrite() is called again, a new
1540	gzip stream will be started in the output. gzread() is able to read such
1541	concatenated gzip streams.
1542
1543	gzflush should be called only when strictly necessary because it will
1544	degrade compression if called too often.
1545	*/
1546
1547	/*
1548	ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1549	z_off_t offset, int whence));
1550
1551	Sets the starting position for the next gzread or gzwrite on the given
1552	compressed file. The offset represents a number of bytes in the
1553	uncompressed data stream. The whence parameter is defined as in lseek(2);
1554	the value SEEK_END is not supported.
1555
1556	If the file is opened for reading, this function is emulated but can be
1557	extremely slow. If the file is opened for writing, only forward seeks are
1558	supported; gzseek then compresses a sequence of zeroes up to the new
1559	starting position.
1560
1561	gzseek returns the resulting offset location as measured in bytes from
1562	the beginning of the uncompressed stream, or -1 in case of error, in
1563	particular if the file is opened for writing and the new starting position
1564	would be before the current position.
1565	*/
1566
1567	ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1568	/*
1569	Rewinds the given file. This function is supported only for reading.
1570
1571	gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1572	*/
1573
1574	/*
1575	ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1576
1577	Returns the starting position for the next gzread or gzwrite on the given
1578	compressed file. This position represents a number of bytes in the
1579	uncompressed data stream, and is zero when starting, even if appending or
1580	reading a gzip stream from the middle of a file using gzdopen().
1581
1582	gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1583	*/
1584
1585	/*
1586	ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1587
1588	Returns the current offset in the file being read or written. This offset
1589	includes the count of bytes that precede the gzip stream, for example when
1590	appending or when using gzdopen() for reading. When reading, the offset
1591	does not include as yet unused buffered input. This information can be used
1592	for a progress indicator. On error, gzoffset() returns -1.
1593	*/
1594
1595	ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1596	/*
1597	Returns true (1) if the end-of-file indicator has been set while reading,
1598	false (0) otherwise. Note that the end-of-file indicator is set only if the
1599	read tried to go past the end of the input, but came up short. Therefore,
1600	just like feof(), gzeof() may return false even if there is no more data to
1601	read, in the event that the last read request was for the exact number of
1602	bytes remaining in the input file. This will happen if the input file size
1603	is an exact multiple of the buffer size.
1604
1605	If gzeof() returns true, then the read functions will return no more data,
1606	unless the end-of-file indicator is reset by gzclearerr() and the input file
1607	has grown since the previous end of file was detected.
1608	*/
1609
1610	ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1611	/*
1612	Returns true (1) if file is being copied directly while reading, or false
1613	(0) if file is a gzip stream being decompressed.
1614
1615	If the input file is empty, gzdirect() will return true, since the input
1616	does not contain a gzip stream.
1617
1618	If gzdirect() is used immediately after gzopen() or gzdopen() it will
1619	cause buffers to be allocated to allow reading the file to determine if it
1620	is a gzip file. Therefore if gzbuffer() is used, it should be called before
1621	gzdirect().
1622
1623	When writing, gzdirect() returns true (1) if transparent writing was
1624	requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1625	gzdirect() is not needed when writing. Transparent writing must be
1626	explicitly requested, so the application already knows the answer. When
1627	linking statically, using gzdirect() will include all of the zlib code for
1628	gzip file reading and decompression, which may not be desired.)
1629	*/
1630
1631	ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1632	/*
1633	Flushes all pending output if necessary, closes the compressed file and
1634	deallocates the (de)compression state. Note that once file is closed, you
1635	cannot call gzerror with file, since its structures have been deallocated.
1636	gzclose must not be called more than once on the same file, just as free
1637	must not be called more than once on the same allocation.
1638
1639	gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1640	file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1641	last read ended in the middle of a gzip stream, or Z_OK on success.
1642	*/
1643
1644	ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1645	ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1646	/*
1647	Same as gzclose(), but gzclose_r() is only for use when reading, and
1648	gzclose_w() is only for use when writing or appending. The advantage to
1649	using these instead of gzclose() is that they avoid linking in zlib
1650	compression or decompression code that is not used when only reading or only
1651	writing respectively. If gzclose() is used, then both compression and
1652	decompression code will be included the application when linking to a static
1653	zlib library.
1654	*/
1655
1656	ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1657	/*
1658	Returns the error message for the last error which occurred on the given
1659	compressed file. errnum is set to zlib error number. If an error occurred
1660	in the file system and not in the compression library, errnum is set to
1661	Z_ERRNO and the application may consult errno to get the exact error code.
1662
1663	The application must not modify the returned string. Future calls to
1664	this function may invalidate the previously returned string. If file is
1665	closed, then the string previously returned by gzerror will no longer be
1666	available.
1667
1668	gzerror() should be used to distinguish errors from end-of-file for those
1669	functions above that do not distinguish those cases in their return values.
1670	*/
1671
1672	ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1673	/*
1674	Clears the error and end-of-file flags for file. This is analogous to the
1675	clearerr() function in stdio. This is useful for continuing to read a gzip
1676	file that is being written concurrently.
1677	*/
1678
1679	#endif /* !Z_SOLO */
1680
1681	/* checksum functions */
1682
1683	/*
1684	These functions are not related to compression but are exported
1685	anyway because they might be useful in applications using the compression
1686	library.
1687	*/
1688
1689	ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1690	/*
1691	Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1692	return the updated checksum. If buf is Z_NULL, this function returns the
1693	required initial value for the checksum.
1694
1695	An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1696	much faster.
1697
1698	Usage example:
1699
1700	uLong adler = adler32(0L, Z_NULL, 0);
1701
1702	while (read_buffer(buffer, length) != EOF) {
1703	adler = adler32(adler, buffer, length);
1704	}
1705	if (adler != original_adler) error();
1706	*/
1707
1708	ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf,
1709	z_size_t len));
1710	/*
1711	Same as adler32(), but with a size_t length.
1712	*/
1713
1714	/*
1715	ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1716	z_off_t len2));
1717
1718	Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1719	and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1720	each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1721	seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1722	that the z_off_t type (like off_t) is a signed integer. If len2 is
1723	negative, the result has no meaning or utility.
1724	*/
1725
1726	ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1727	/*
1728	Update a running CRC-32 with the bytes buf[0..len-1] and return the
1729	updated CRC-32. If buf is Z_NULL, this function returns the required
1730	initial value for the crc. Pre- and post-conditioning (one's complement) is
1731	performed within this function so it shouldn't be done by the application.
1732
1733	Usage example:
1734
1735	uLong crc = crc32(0L, Z_NULL, 0);
1736
1737	while (read_buffer(buffer, length) != EOF) {
1738	crc = crc32(crc, buffer, length);
1739	}
1740	if (crc != original_crc) error();
1741	*/
1742
1743	ZEXTERN uLong ZEXPORT crc32_z OF((uLong adler, const Bytef *buf,
1744	z_size_t len));
1745	/*
1746	Same as crc32(), but with a size_t length.
1747	*/
1748
1749	/*
1750	ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1751
1752	Combine two CRC-32 check values into one. For two sequences of bytes,
1753	seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1754	calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1755	check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1756	len2.
1757	*/
1758
1759
1760	/* various hacks, don't look :) */
1761
1762	/* deflateInit and inflateInit are macros to allow checking the zlib version
1763	* and the compiler's view of z_stream:
1764	*/
1765	ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1766	const char *version, int stream_size));
1767	ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1768	const char *version, int stream_size));
1769	ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1770	int windowBits, int memLevel,
1771	int strategy, const char *version,
1772	int stream_size));
1773	ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1774	const char *version, int stream_size));
1775	ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1776	unsigned char FAR *window,
1777	const char *version,
1778	int stream_size));
1779	#ifdef Z_PREFIX_SET
1780	# define z_deflateInit(strm, level) \
1781	deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1782	# define z_inflateInit(strm) \
1783	inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1784	# define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1785	deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1786	(strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1787	# define z_inflateInit2(strm, windowBits) \
1788	inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1789	(int)sizeof(z_stream))
1790	# define z_inflateBackInit(strm, windowBits, window) \
1791	inflateBackInit_((strm), (windowBits), (window), \
1792	ZLIB_VERSION, (int)sizeof(z_stream))
1793	#else
1794	# define deflateInit(strm, level) \
1795	deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1796	# define inflateInit(strm) \
1797	inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1798	# define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1799	deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1800	(strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1801	# define inflateInit2(strm, windowBits) \
1802	inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1803	(int)sizeof(z_stream))
1804	# define inflateBackInit(strm, windowBits, window) \
1805	inflateBackInit_((strm), (windowBits), (window), \
1806	ZLIB_VERSION, (int)sizeof(z_stream))
1807	#endif
1808
1809	#ifndef Z_SOLO
1810
1811	/* gzgetc() macro and its supporting function and exposed data structure. Note
1812	* that the real internal state is much larger than the exposed structure.
1813	* This abbreviated structure exposes just enough for the gzgetc() macro. The
1814	* user should not mess with these exposed elements, since their names or
1815	* behavior could change in the future, perhaps even capriciously. They can
1816	* only be used by the gzgetc() macro. You have been warned.
1817	*/
1818	struct gzFile_s {
1819	unsigned have;
1820	unsigned char *next;
1821	z_off64_t pos;
1822	};
1823	ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
1824	#ifdef Z_PREFIX_SET
1825	# undef z_gzgetc
1826	# define z_gzgetc(g) \
1827	((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1828	#else
1829	# define gzgetc(g) \
1830	((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1831	#endif
1832
1833	/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1834	* change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1835	* both are true, the application gets the *64 functions, and the regular
1836	* functions are changed to 64 bits) -- in case these are set on systems
1837	* without large file support, _LFS64_LARGEFILE must also be true
1838	*/
1839	#ifdef Z_LARGE64
1840	ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1841	ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1842	ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1843	ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1844	ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1845	ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1846	#endif
1847
1848	#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1849	# ifdef Z_PREFIX_SET
1850	# define z_gzopen z_gzopen64
1851	# define z_gzseek z_gzseek64
1852	# define z_gztell z_gztell64
1853	# define z_gzoffset z_gzoffset64
1854	# define z_adler32_combine z_adler32_combine64
1855	# define z_crc32_combine z_crc32_combine64
1856	# else
1857	# define gzopen gzopen64
1858	# define gzseek gzseek64
1859	# define gztell gztell64
1860	# define gzoffset gzoffset64
1861	# define adler32_combine adler32_combine64
1862	# define crc32_combine crc32_combine64
1863	# endif
1864	# ifndef Z_LARGE64
1865	ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1866	ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1867	ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1868	ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1869	ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1870	ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1871	# endif
1872	#else
1873	ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1874	ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1875	ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1876	ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1877	ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1878	ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1879	#endif
1880
1881	#else /* Z_SOLO */
1882
1883	ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1884	ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1885
1886	#endif /* !Z_SOLO */
1887
1888	/* undocumented functions */
1889	ZEXTERN const char * ZEXPORT zError OF((int));
1890	ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1891	ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1892	ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1893	ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int));
1894	ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF ((z_streamp));
1895	ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1896	ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1897	#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
1898	ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1899	const char *mode));
1900	#endif
1901	#if defined(STDC) || defined(Z_HAVE_STDARG_H)
1902	# ifndef Z_SOLO
1903	ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1904	const char *format,
1905	va_list va));
1906	# endif
1907	#endif
1908
1909	#ifdef __cplusplus
1910	}
1911	#endif
1912
1913	#endif /* ZLIB_H */
1914