1/* $NetBSD: zlib.h,v 1.4 2017/01/10 01:27:41 christos Exp $ */
2
3/* zlib.h -- interface of the 'zlib' general purpose compression library
4 version 1.2.10, January 2nd, 2017
5
6 Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
7
8 This software is provided 'as-is', without any express or implied
9 warranty. In no event will the authors be held liable for any damages
10 arising from the use of this software.
11
12 Permission is granted to anyone to use this software for any purpose,
13 including commercial applications, and to alter it and redistribute it
14 freely, subject to the following restrictions:
15
16 1. The origin of this software must not be misrepresented; you must not
17 claim that you wrote the original software. If you use this software
18 in a product, an acknowledgment in the product documentation would be
19 appreciated but is not required.
20 2. Altered source versions must be plainly marked as such, and must not be
21 misrepresented as being the original software.
22 3. This notice may not be removed or altered from any source distribution.
23
24 Jean-loup Gailly Mark Adler
25 jloup@gzip.org madler@alumni.caltech.edu
26
27
28 The data format used by the zlib library is described by RFCs (Request for
29 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
30 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
31*/
32
33#ifndef ZLIB_H
34#define ZLIB_H
35
36#include "zconf.h"
37
38#ifdef __cplusplus
39extern "C" {
40#endif
41
42#define ZLIB_VERSION "1.2.10"
43#define ZLIB_VERNUM 0x12a0
44#define ZLIB_VER_MAJOR 1
45#define ZLIB_VER_MINOR 2
46#define ZLIB_VER_REVISION 10
47#define ZLIB_VER_SUBREVISION 0
48
49/*
50 The 'zlib' compression library provides in-memory compression and
51 decompression functions, including integrity checks of the uncompressed data.
52 This version of the library supports only one compression method (deflation)
53 but other algorithms will be added later and will have the same stream
54 interface.
55
56 Compression can be done in a single step if the buffers are large enough,
57 or can be done by repeated calls of the compression function. In the latter
58 case, the application must provide more input and/or consume the output
59 (providing more output space) before each call.
60
61 The compressed data format used by default by the in-memory functions is
62 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
63 around a deflate stream, which is itself documented in RFC 1951.
64
65 The library also supports reading and writing files in gzip (.gz) format
66 with an interface similar to that of stdio using the functions that start
67 with "gz". The gzip format is different from the zlib format. gzip is a
68 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
69
70 This library can optionally read and write gzip and raw deflate streams in
71 memory as well.
72
73 The zlib format was designed to be compact and fast for use in memory
74 and on communications channels. The gzip format was designed for single-
75 file compression on file systems, has a larger header than zlib to maintain
76 directory information, and uses a different, slower check method than zlib.
77
78 The library does not install any signal handler. The decoder checks
79 the consistency of the compressed data, so the library should never crash
80 even in the case of corrupted input.
81*/
82
83typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
84typedef void (*free_func) OF((voidpf opaque, voidpf address));
85
86struct internal_state;
87
88typedef struct z_stream_s {
89 z_const Bytef *next_in; /* next input byte */
90 uInt avail_in; /* number of bytes available at next_in */
91 uLong total_in; /* total number of input bytes read so far */
92
93 Bytef *next_out; /* next output byte will go here */
94 uInt avail_out; /* remaining free space at next_out */
95 uLong total_out; /* total number of bytes output so far */
96
97 z_const char *msg; /* last error message, NULL if no error */
98 struct internal_state FAR *state; /* not visible by applications */
99
100 alloc_func zalloc; /* used to allocate the internal state */
101 free_func zfree; /* used to free the internal state */
102 voidpf opaque; /* private data object passed to zalloc and zfree */
103
104 int data_type; /* best guess about the data type: binary or text
105 for deflate, or the decoding state for inflate */
106 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */
107 uLong reserved; /* reserved for future use */
108} z_stream;
109
110typedef z_stream FAR *z_streamp;
111
112/*
113 gzip header information passed to and from zlib routines. See RFC 1952
114 for more details on the meanings of these fields.
115*/
116typedef struct gz_header_s {
117 int text; /* true if compressed data believed to be text */
118 uLong time; /* modification time */
119 int xflags; /* extra flags (not used when writing a gzip file) */
120 int os; /* operating system */
121 Bytef *extra; /* pointer to extra field or Z_NULL if none */
122 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
123 uInt extra_max; /* space at extra (only when reading header) */
124 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
125 uInt name_max; /* space at name (only when reading header) */
126 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
127 uInt comm_max; /* space at comment (only when reading header) */
128 int hcrc; /* true if there was or will be a header crc */
129 int done; /* true when done reading gzip header (not used
130 when writing a gzip file) */
131} gz_header;
132
133typedef gz_header FAR *gz_headerp;
134
135/*
136 The application must update next_in and avail_in when avail_in has dropped
137 to zero. It must update next_out and avail_out when avail_out has dropped
138 to zero. The application must initialize zalloc, zfree and opaque before
139 calling the init function. All other fields are set by the compression
140 library and must not be updated by the application.
141
142 The opaque value provided by the application will be passed as the first
143 parameter for calls of zalloc and zfree. This can be useful for custom
144 memory management. The compression library attaches no meaning to the
145 opaque value.
146
147 zalloc must return Z_NULL if there is not enough memory for the object.
148 If zlib is used in a multi-threaded application, zalloc and zfree must be
149 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
150 Z_NULL on entry to the initialization function, they are set to internal
151 routines that use the standard library functions malloc() and free().
152
153 On 16-bit systems, the functions zalloc and zfree must be able to allocate
154 exactly 65536 bytes, but will not be required to allocate more than this if
155 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
156 returned by zalloc for objects of exactly 65536 bytes *must* have their
157 offset normalized to zero. The default allocation function provided by this
158 library ensures this (see zutil.c). To reduce memory requirements and avoid
159 any allocation of 64K objects, at the expense of compression ratio, compile
160 the library with -DMAX_WBITS=14 (see zconf.h).
161
162 The fields total_in and total_out can be used for statistics or progress
163 reports. After compression, total_in holds the total size of the
164 uncompressed data and may be saved for use by the decompressor (particularly
165 if the decompressor wants to decompress everything in a single step).
166*/
167
168 /* constants */
169
170#define Z_NO_FLUSH 0
171#define Z_PARTIAL_FLUSH 1
172#define Z_SYNC_FLUSH 2
173#define Z_FULL_FLUSH 3
174#define Z_FINISH 4
175#define Z_BLOCK 5
176#define Z_TREES 6
177/* Allowed flush values; see deflate() and inflate() below for details */
178
179#define Z_OK 0
180#define Z_STREAM_END 1
181#define Z_NEED_DICT 2
182#define Z_ERRNO (-1)
183#define Z_STREAM_ERROR (-2)
184#define Z_DATA_ERROR (-3)
185#define Z_MEM_ERROR (-4)
186#define Z_BUF_ERROR (-5)
187#define Z_VERSION_ERROR (-6)
188/* Return codes for the compression/decompression functions. Negative values
189 * are errors, positive values are used for special but normal events.
190 */
191
192#define Z_NO_COMPRESSION 0
193#define Z_BEST_SPEED 1
194#define Z_BEST_COMPRESSION 9
195#define Z_DEFAULT_COMPRESSION (-1)
196/* compression levels */
197
198#define Z_FILTERED 1
199#define Z_HUFFMAN_ONLY 2
200#define Z_RLE 3
201#define Z_FIXED 4
202#define Z_DEFAULT_STRATEGY 0
203/* compression strategy; see deflateInit2() below for details */
204
205#define Z_BINARY 0
206#define Z_TEXT 1
207#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
208#define Z_UNKNOWN 2
209/* Possible values of the data_type field for deflate() */
210
211#define Z_DEFLATED 8
212/* The deflate compression method (the only one supported in this version) */
213
214#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
215
216#define zlib_version zlibVersion()
217/* for compatibility with versions < 1.0.2 */
218
219
220 /* basic functions */
221
222ZEXTERN const char * ZEXPORT zlibVersion OF((void));
223/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
224 If the first character differs, the library code actually used is not
225 compatible with the zlib.h header file used by the application. This check
226 is automatically made by deflateInit and inflateInit.
227 */
228
229/*
230ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
231
232 Initializes the internal stream state for compression. The fields
233 zalloc, zfree and opaque must be initialized before by the caller. If
234 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
235 allocation functions.
236
237 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
238 1 gives best speed, 9 gives best compression, 0 gives no compression at all
239 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
240 requests a default compromise between speed and compression (currently
241 equivalent to level 6).
242
243 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
244 memory, Z_STREAM_ERROR if level is not a valid compression level, or
245 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
246 with the version assumed by the caller (ZLIB_VERSION). msg is set to null
247 if there is no error message. deflateInit does not perform any compression:
248 this will be done by deflate().
249*/
250
251
252ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
253/*
254 deflate compresses as much data as possible, and stops when the input
255 buffer becomes empty or the output buffer becomes full. It may introduce
256 some output latency (reading input without producing any output) except when
257 forced to flush.
258
259 The detailed semantics are as follows. deflate performs one or both of the
260 following actions:
261
262 - Compress more input starting at next_in and update next_in and avail_in
263 accordingly. If not all input can be processed (because there is not
264 enough room in the output buffer), next_in and avail_in are updated and
265 processing will resume at this point for the next call of deflate().
266
267 - Generate more output starting at next_out and update next_out and avail_out
268 accordingly. This action is forced if the parameter flush is non zero.
269 Forcing flush frequently degrades the compression ratio, so this parameter
270 should be set only when necessary. Some output may be provided even if
271 flush is zero.
272
273 Before the call of deflate(), the application should ensure that at least
274 one of the actions is possible, by providing more input and/or consuming more
275 output, and updating avail_in or avail_out accordingly; avail_out should
276 never be zero before the call. The application can consume the compressed
277 output when it wants, for example when the output buffer is full (avail_out
278 == 0), or after each call of deflate(). If deflate returns Z_OK and with
279 zero avail_out, it must be called again after making room in the output
280 buffer because there might be more output pending. See deflatePending(),
281 which can be used if desired to determine whether or not there is more ouput
282 in that case.
283
284 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
285 decide how much data to accumulate before producing output, in order to
286 maximize compression.
287
288 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
289 flushed to the output buffer and the output is aligned on a byte boundary, so
290 that the decompressor can get all input data available so far. (In
291 particular avail_in is zero after the call if enough output space has been
292 provided before the call.) Flushing may degrade compression for some
293 compression algorithms and so it should be used only when necessary. This
294 completes the current deflate block and follows it with an empty stored block
295 that is three bits plus filler bits to the next byte, followed by four bytes
296 (00 00 ff ff).
297
298 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
299 output buffer, but the output is not aligned to a byte boundary. All of the
300 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
301 This completes the current deflate block and follows it with an empty fixed
302 codes block that is 10 bits long. This assures that enough bytes are output
303 in order for the decompressor to finish the block before the empty fixed
304 codes block.
305
306 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
307 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
308 seven bits of the current block are held to be written as the next byte after
309 the next deflate block is completed. In this case, the decompressor may not
310 be provided enough bits at this point in order to complete decompression of
311 the data provided so far to the compressor. It may need to wait for the next
312 block to be emitted. This is for advanced applications that need to control
313 the emission of deflate blocks.
314
315 If flush is set to Z_FULL_FLUSH, all output is flushed as with
316 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
317 restart from this point if previous compressed data has been damaged or if
318 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
319 compression.
320
321 If deflate returns with avail_out == 0, this function must be called again
322 with the same value of the flush parameter and more output space (updated
323 avail_out), until the flush is complete (deflate returns with non-zero
324 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
325 avail_out is greater than six to avoid repeated flush markers due to
326 avail_out == 0 on return.
327
328 If the parameter flush is set to Z_FINISH, pending input is processed,
329 pending output is flushed and deflate returns with Z_STREAM_END if there was
330 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this
331 function must be called again with Z_FINISH and more output space (updated
332 avail_out) but no more input data, until it returns with Z_STREAM_END or an
333 error. After deflate has returned Z_STREAM_END, the only possible operations
334 on the stream are deflateReset or deflateEnd.
335
336 Z_FINISH can be used in the first deflate call after deflateInit if all the
337 compression is to be done in a single step. In order to complete in one
338 call, avail_out must be at least the value returned by deflateBound (see
339 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough
340 output space is provided, deflate will not return Z_STREAM_END, and it must
341 be called again as described above.
342
343 deflate() sets strm->adler to the Adler-32 checksum of all input read
344 so far (that is, total_in bytes). If a gzip stream is being generated, then
345 strm->adler will be the CRC-32 checksum of the input read so far. (See
346 deflateInit2 below.)
347
348 deflate() may update strm->data_type if it can make a good guess about
349 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is
350 considered binary. This field is only for information purposes and does not
351 affect the compression algorithm in any manner.
352
353 deflate() returns Z_OK if some progress has been made (more input
354 processed or more output produced), Z_STREAM_END if all input has been
355 consumed and all output has been produced (only when flush is set to
356 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
357 if next_in or next_out was Z_NULL or the state was inadvertently written over
358 by the application), or Z_BUF_ERROR if no progress is possible (for example
359 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
360 deflate() can be called again with more input and more output space to
361 continue compressing.
362*/
363
364
365ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
366/*
367 All dynamically allocated data structures for this stream are freed.
368 This function discards any unprocessed input and does not flush any pending
369 output.
370
371 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
372 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
373 prematurely (some input or output was discarded). In the error case, msg
374 may be set but then points to a static string (which must not be
375 deallocated).
376*/
377
378
379/*
380ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
381
382 Initializes the internal stream state for decompression. The fields
383 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
384 the caller. In the current version of inflate, the provided input is not
385 read or consumed. The allocation of a sliding window will be deferred to
386 the first call of inflate (if the decompression does not complete on the
387 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates
388 them to use default allocation functions.
389
390 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
391 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
392 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
393 invalid, such as a null pointer to the structure. msg is set to null if
394 there is no error message. inflateInit does not perform any decompression.
395 Actual decompression will be done by inflate(). So next_in, and avail_in,
396 next_out, and avail_out are unused and unchanged. The current
397 implementation of inflateInit() does not process any header information --
398 that is deferred until inflate() is called.
399*/
400
401
402ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
403/*
404 inflate decompresses as much data as possible, and stops when the input
405 buffer becomes empty or the output buffer becomes full. It may introduce
406 some output latency (reading input without producing any output) except when
407 forced to flush.
408
409 The detailed semantics are as follows. inflate performs one or both of the
410 following actions:
411
412 - Decompress more input starting at next_in and update next_in and avail_in
413 accordingly. If not all input can be processed (because there is not
414 enough room in the output buffer), then next_in and avail_in are updated
415 accordingly, and processing will resume at this point for the next call of
416 inflate().
417
418 - Generate more output starting at next_out and update next_out and avail_out
419 accordingly. inflate() provides as much output as possible, until there is
420 no more input data or no more space in the output buffer (see below about
421 the flush parameter).
422
423 Before the call of inflate(), the application should ensure that at least
424 one of the actions is possible, by providing more input and/or consuming more
425 output, and updating the next_* and avail_* values accordingly. If the
426 caller of inflate() does not provide both available input and available
427 output space, it is possible that there will be no progress made. The
428 application can consume the uncompressed output when it wants, for example
429 when the output buffer is full (avail_out == 0), or after each call of
430 inflate(). If inflate returns Z_OK and with zero avail_out, it must be
431 called again after making room in the output buffer because there might be
432 more output pending.
433
434 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
435 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
436 output as possible to the output buffer. Z_BLOCK requests that inflate()
437 stop if and when it gets to the next deflate block boundary. When decoding
438 the zlib or gzip format, this will cause inflate() to return immediately
439 after the header and before the first block. When doing a raw inflate,
440 inflate() will go ahead and process the first block, and will return when it
441 gets to the end of that block, or when it runs out of data.
442
443 The Z_BLOCK option assists in appending to or combining deflate streams.
444 To assist in this, on return inflate() always sets strm->data_type to the
445 number of unused bits in the last byte taken from strm->next_in, plus 64 if
446 inflate() is currently decoding the last block in the deflate stream, plus
447 128 if inflate() returned immediately after decoding an end-of-block code or
448 decoding the complete header up to just before the first byte of the deflate
449 stream. The end-of-block will not be indicated until all of the uncompressed
450 data from that block has been written to strm->next_out. The number of
451 unused bits may in general be greater than seven, except when bit 7 of
452 data_type is set, in which case the number of unused bits will be less than
453 eight. data_type is set as noted here every time inflate() returns for all
454 flush options, and so can be used to determine the amount of currently
455 consumed input in bits.
456
457 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
458 end of each deflate block header is reached, before any actual data in that
459 block is decoded. This allows the caller to determine the length of the
460 deflate block header for later use in random access within a deflate block.
461 256 is added to the value of strm->data_type when inflate() returns
462 immediately after reaching the end of the deflate block header.
463
464 inflate() should normally be called until it returns Z_STREAM_END or an
465 error. However if all decompression is to be performed in a single step (a
466 single call of inflate), the parameter flush should be set to Z_FINISH. In
467 this case all pending input is processed and all pending output is flushed;
468 avail_out must be large enough to hold all of the uncompressed data for the
469 operation to complete. (The size of the uncompressed data may have been
470 saved by the compressor for this purpose.) The use of Z_FINISH is not
471 required to perform an inflation in one step. However it may be used to
472 inform inflate that a faster approach can be used for the single inflate()
473 call. Z_FINISH also informs inflate to not maintain a sliding window if the
474 stream completes, which reduces inflate's memory footprint. If the stream
475 does not complete, either because not all of the stream is provided or not
476 enough output space is provided, then a sliding window will be allocated and
477 inflate() can be called again to continue the operation as if Z_NO_FLUSH had
478 been used.
479
480 In this implementation, inflate() always flushes as much output as
481 possible to the output buffer, and always uses the faster approach on the
482 first call. So the effects of the flush parameter in this implementation are
483 on the return value of inflate() as noted below, when inflate() returns early
484 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
485 memory for a sliding window when Z_FINISH is used.
486
487 If a preset dictionary is needed after this call (see inflateSetDictionary
488 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
489 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
490 strm->adler to the Adler-32 checksum of all output produced so far (that is,
491 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
492 below. At the end of the stream, inflate() checks that its computed Adler-32
493 checksum is equal to that saved by the compressor and returns Z_STREAM_END
494 only if the checksum is correct.
495
496 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
497 deflate data. The header type is detected automatically, if requested when
498 initializing with inflateInit2(). Any information contained in the gzip
499 header is not retained unless inflateGetHeader() is used. When processing
500 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
501 produced so far. The CRC-32 is checked against the gzip trailer, as is the
502 uncompressed length, modulo 2^32.
503
504 inflate() returns Z_OK if some progress has been made (more input processed
505 or more output produced), Z_STREAM_END if the end of the compressed data has
506 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
507 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
508 corrupted (input stream not conforming to the zlib format or incorrect check
509 value, in which case strm->msg points to a string with a more specific
510 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
511 next_in or next_out was Z_NULL, or the state was inadvertently written over
512 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
513 if no progress was possible or if there was not enough room in the output
514 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
515 inflate() can be called again with more input and more output space to
516 continue decompressing. If Z_DATA_ERROR is returned, the application may
517 then call inflateSync() to look for a good compression block if a partial
518 recovery of the data is to be attempted.
519*/
520
521
522ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
523/*
524 All dynamically allocated data structures for this stream are freed.
525 This function discards any unprocessed input and does not flush any pending
526 output.
527
528 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
529 was inconsistent.
530*/
531
532
533 /* Advanced functions */
534
535/*
536 The following functions are needed only in some special applications.
537*/
538
539/*
540ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
541 int level,
542 int method,
543 int windowBits,
544 int memLevel,
545 int strategy));
546
547 This is another version of deflateInit with more compression options. The
548 fields next_in, zalloc, zfree and opaque must be initialized before by the
549 caller.
550
551 The method parameter is the compression method. It must be Z_DEFLATED in
552 this version of the library.
553
554 The windowBits parameter is the base two logarithm of the window size
555 (the size of the history buffer). It should be in the range 8..15 for this
556 version of the library. Larger values of this parameter result in better
557 compression at the expense of memory usage. The default value is 15 if
558 deflateInit is used instead.
559
560 For the current implementation of deflate(), a windowBits value of 8 (a
561 window size of 256 bytes) is not supported. As a result, a request for 8
562 will result in 9 (a 512-byte window). In that case, providing 8 to
563 inflateInit2() will result in an error when the zlib header with 9 is
564 checked against the initialization of inflate(). The remedy is to not use 8
565 with deflateInit2() with this initialization, or at least in that case use 9
566 with inflateInit2().
567
568 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
569 determines the window size. deflate() will then generate raw deflate data
570 with no zlib header or trailer, and will not compute a check value.
571
572 windowBits can also be greater than 15 for optional gzip encoding. Add
573 16 to windowBits to write a simple gzip header and trailer around the
574 compressed data instead of a zlib wrapper. The gzip header will have no
575 file name, no extra data, no comment, no modification time (set to zero), no
576 header crc, and the operating system will be set to the appropriate value,
577 if the operating system was determined at compile time. If a gzip stream is
578 being written, strm->adler is a CRC-32 instead of an Adler-32.
579
580 For raw deflate or gzip encoding, a request for a 256-byte window is
581 rejected as invalid, since only the zlib header provides a means of
582 transmitting the window size to the decompressor.
583
584 The memLevel parameter specifies how much memory should be allocated
585 for the internal compression state. memLevel=1 uses minimum memory but is
586 slow and reduces compression ratio; memLevel=9 uses maximum memory for
587 optimal speed. The default value is 8. See zconf.h for total memory usage
588 as a function of windowBits and memLevel.
589
590 The strategy parameter is used to tune the compression algorithm. Use the
591 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
592 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
593 string match), or Z_RLE to limit match distances to one (run-length
594 encoding). Filtered data consists mostly of small values with a somewhat
595 random distribution. In this case, the compression algorithm is tuned to
596 compress them better. The effect of Z_FILTERED is to force more Huffman
597 coding and less string matching; it is somewhat intermediate between
598 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
599 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
600 strategy parameter only affects the compression ratio but not the
601 correctness of the compressed output even if it is not set appropriately.
602 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
603 decoder for special applications.
604
605 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
606 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
607 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
608 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
609 set to null if there is no error message. deflateInit2 does not perform any
610 compression: this will be done by deflate().
611*/
612
613ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
614 const Bytef *dictionary,
615 uInt dictLength));
616/*
617 Initializes the compression dictionary from the given byte sequence
618 without producing any compressed output. When using the zlib format, this
619 function must be called immediately after deflateInit, deflateInit2 or
620 deflateReset, and before any call of deflate. When doing raw deflate, this
621 function must be called either before any call of deflate, or immediately
622 after the completion of a deflate block, i.e. after all input has been
623 consumed and all output has been delivered when using any of the flush
624 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
625 compressor and decompressor must use exactly the same dictionary (see
626 inflateSetDictionary).
627
628 The dictionary should consist of strings (byte sequences) that are likely
629 to be encountered later in the data to be compressed, with the most commonly
630 used strings preferably put towards the end of the dictionary. Using a
631 dictionary is most useful when the data to be compressed is short and can be
632 predicted with good accuracy; the data can then be compressed better than
633 with the default empty dictionary.
634
635 Depending on the size of the compression data structures selected by
636 deflateInit or deflateInit2, a part of the dictionary may in effect be
637 discarded, for example if the dictionary is larger than the window size
638 provided in deflateInit or deflateInit2. Thus the strings most likely to be
639 useful should be put at the end of the dictionary, not at the front. In
640 addition, the current implementation of deflate will use at most the window
641 size minus 262 bytes of the provided dictionary.
642
643 Upon return of this function, strm->adler is set to the Adler-32 value
644 of the dictionary; the decompressor may later use this value to determine
645 which dictionary has been used by the compressor. (The Adler-32 value
646 applies to the whole dictionary even if only a subset of the dictionary is
647 actually used by the compressor.) If a raw deflate was requested, then the
648 Adler-32 value is not computed and strm->adler is not set.
649
650 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
651 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
652 inconsistent (for example if deflate has already been called for this stream
653 or if not at a block boundary for raw deflate). deflateSetDictionary does
654 not perform any compression: this will be done by deflate().
655*/
656
657ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm,
658 Bytef *dictionary,
659 uInt *dictLength));
660/*
661 Returns the sliding dictionary being maintained by deflate. dictLength is
662 set to the number of bytes in the dictionary, and that many bytes are copied
663 to dictionary. dictionary must have enough space, where 32768 bytes is
664 always enough. If deflateGetDictionary() is called with dictionary equal to
665 Z_NULL, then only the dictionary length is returned, and nothing is copied.
666 Similary, if dictLength is Z_NULL, then it is not set.
667
668 deflateGetDictionary() may return a length less than the window size, even
669 when more than the window size in input has been provided. It may return up
670 to 258 bytes less in that case, due to how zlib's implementation of deflate
671 manages the sliding window and lookahead for matches, where matches can be
672 up to 258 bytes long. If the application needs the last window-size bytes of
673 input, then that would need to be saved by the application outside of zlib.
674
675 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
676 stream state is inconsistent.
677*/
678
679ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
680 z_streamp source));
681/*
682 Sets the destination stream as a complete copy of the source stream.
683
684 This function can be useful when several compression strategies will be
685 tried, for example when there are several ways of pre-processing the input
686 data with a filter. The streams that will be discarded should then be freed
687 by calling deflateEnd. Note that deflateCopy duplicates the internal
688 compression state which can be quite large, so this strategy is slow and can
689 consume lots of memory.
690
691 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
692 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
693 (such as zalloc being Z_NULL). msg is left unchanged in both source and
694 destination.
695*/
696
697ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
698/*
699 This function is equivalent to deflateEnd followed by deflateInit, but
700 does not free and reallocate the internal compression state. The stream
701 will leave the compression level and any other attributes that may have been
702 set unchanged.
703
704 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
705 stream state was inconsistent (such as zalloc or state being Z_NULL).
706*/
707
708ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
709 int level,
710 int strategy));
711/*
712 Dynamically update the compression level and compression strategy. The
713 interpretation of level and strategy is as in deflateInit2(). This can be
714 used to switch between compression and straight copy of the input data, or
715 to switch to a different kind of input data requiring a different strategy.
716 If the compression approach (which is a function of the level) or the
717 strategy is changed, then the input available so far is compressed with the
718 old level and strategy using deflate(strm, Z_BLOCK). There are three
719 approaches for the compression levels 0, 1..3, and 4..9 respectively. The
720 new level and strategy will take effect at the next call 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
744ZEXTERN 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
761ZEXTERN 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
776ZEXTERN 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
791ZEXTERN 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
808ZEXTERN 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/*
833ZEXTERN 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
885ZEXTERN 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
908ZEXTERN 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
923ZEXTERN 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
942ZEXTERN 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
958ZEXTERN 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
968ZEXTERN 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
982ZEXTERN 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
1003ZEXTERN 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
1031ZEXTERN 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/*
1072ZEXTERN 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
1093typedef unsigned (*in_func) OF((void FAR *,
1094 z_const unsigned char FAR * FAR *));
1095typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1096
1097ZEXTERN 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
1167ZEXTERN 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
1175ZEXTERN 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
1228ZEXTERN 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
1243ZEXTERN 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
1259ZEXTERN 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
1266ZEXTERN 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
1284ZEXTERN 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
1301typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1302
1303/*
1304ZEXTERN 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
1341ZEXTERN 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
1364ZEXTERN 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
1380ZEXTERN 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
1391ZEXTERN 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
1421ZEXTERN 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
1447ZEXTERN 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
1455ZEXTERN 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
1469ZEXTERN 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
1484ZEXTERN 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
1492ZEXTERN 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
1505ZEXTERN 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
1511ZEXTERN 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
1520ZEXTERN 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
1532ZEXTERN 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/*
1548ZEXTERN 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
1567ZEXTERN 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/*
1575ZEXTERN 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/*
1586ZEXTERN 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
1595ZEXTERN 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
1610ZEXTERN 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
1631ZEXTERN 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
1644ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1645ZEXTERN 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
1656ZEXTERN 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
1672ZEXTERN 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
1689ZEXTERN 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
1708ZEXTERN 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/*
1715ZEXTERN 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#if !defined(_KERNEL) && !defined(_STANDALONE)
1727ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1728#endif
1729/*
1730 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1731 updated CRC-32. If buf is Z_NULL, this function returns the required
1732 initial value for the crc. Pre- and post-conditioning (one's complement) is
1733 performed within this function so it shouldn't be done by the application.
1734
1735 Usage example:
1736
1737 uLong crc = crc32(0L, Z_NULL, 0);
1738
1739 while (read_buffer(buffer, length) != EOF) {
1740 crc = crc32(crc, buffer, length);
1741 }
1742 if (crc != original_crc) error();
1743*/
1744
1745ZEXTERN uLong ZEXPORT crc32_z OF((uLong adler, const Bytef *buf,
1746 z_size_t len));
1747/*
1748 Same as crc32(), but with a size_t length.
1749*/
1750
1751/*
1752ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1753
1754 Combine two CRC-32 check values into one. For two sequences of bytes,
1755 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1756 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1757 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1758 len2.
1759*/
1760
1761
1762 /* various hacks, don't look :) */
1763
1764/* deflateInit and inflateInit are macros to allow checking the zlib version
1765 * and the compiler's view of z_stream:
1766 */
1767ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1768 const char *version, int stream_size));
1769ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1770 const char *version, int stream_size));
1771ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1772 int windowBits, int memLevel,
1773 int strategy, const char *version,
1774 int stream_size));
1775ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1776 const char *version, int stream_size));
1777ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1778 unsigned char FAR *window,
1779 const char *version,
1780 int stream_size));
1781#ifdef Z_PREFIX_SET
1782# define z_deflateInit(strm, level) \
1783 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1784# define z_inflateInit(strm) \
1785 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1786# define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1787 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1788 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1789# define z_inflateInit2(strm, windowBits) \
1790 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1791 (int)sizeof(z_stream))
1792# define z_inflateBackInit(strm, windowBits, window) \
1793 inflateBackInit_((strm), (windowBits), (window), \
1794 ZLIB_VERSION, (int)sizeof(z_stream))
1795#else
1796# define deflateInit(strm, level) \
1797 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1798# define inflateInit(strm) \
1799 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1800# define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1801 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1802 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1803# define inflateInit2(strm, windowBits) \
1804 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1805 (int)sizeof(z_stream))
1806# define inflateBackInit(strm, windowBits, window) \
1807 inflateBackInit_((strm), (windowBits), (window), \
1808 ZLIB_VERSION, (int)sizeof(z_stream))
1809#endif
1810
1811#ifndef Z_SOLO
1812
1813/* gzgetc() macro and its supporting function and exposed data structure. Note
1814 * that the real internal state is much larger than the exposed structure.
1815 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1816 * user should not mess with these exposed elements, since their names or
1817 * behavior could change in the future, perhaps even capriciously. They can
1818 * only be used by the gzgetc() macro. You have been warned.
1819 */
1820struct gzFile_s {
1821 unsigned have;
1822 unsigned char *next;
1823 z_off64_t pos;
1824};
1825ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
1826#ifdef Z_PREFIX_SET
1827# undef z_gzgetc
1828# define z_gzgetc(g) \
1829 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1830#else
1831# define gzgetc(g) \
1832 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1833#endif
1834
1835/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1836 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1837 * both are true, the application gets the *64 functions, and the regular
1838 * functions are changed to 64 bits) -- in case these are set on systems
1839 * without large file support, _LFS64_LARGEFILE must also be true
1840 */
1841#ifdef Z_LARGE64
1842 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1843 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1844 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1845 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1846 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1847 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1848#endif
1849
1850#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1851# ifdef Z_PREFIX_SET
1852# define z_gzopen z_gzopen64
1853# define z_gzseek z_gzseek64
1854# define z_gztell z_gztell64
1855# define z_gzoffset z_gzoffset64
1856# define z_adler32_combine z_adler32_combine64
1857# define z_crc32_combine z_crc32_combine64
1858# else
1859# define gzopen gzopen64
1860# define gzseek gzseek64
1861# define gztell gztell64
1862# define gzoffset gzoffset64
1863# define adler32_combine adler32_combine64
1864# define crc32_combine crc32_combine64
1865# endif
1866# ifndef Z_LARGE64
1867 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1868 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1869 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1870 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1871 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1872 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1873# endif
1874#else
1875 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1876 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1877 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1878 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1879 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1880 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1881#endif
1882
1883#else /* Z_SOLO */
1884
1885 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1886 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1887
1888#endif /* !Z_SOLO */
1889
1890/* undocumented functions */
1891ZEXTERN const char * ZEXPORT zError OF((int));
1892ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1893ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1894ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1895ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int));
1896ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF ((z_streamp));
1897ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1898ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1899#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
1900ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1901 const char *mode));
1902#endif
1903#if defined(STDC) || defined(Z_HAVE_STDARG_H)
1904# ifndef Z_SOLO
1905ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1906 const char *format,
1907 va_list va));
1908# endif
1909#endif
1910
1911#ifdef __cplusplus
1912}
1913#endif
1914
1915#endif /* ZLIB_H */
1916