1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* zlib.h -- interface of the 'zlib' general purpose compression library
26 version 1.2.11, January 15th, 2017
27
28 Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
29
30 This software is provided 'as-is', without any express or implied
31 warranty. In no event will the authors be held liable for any damages
32 arising from the use of this software.
33
34 Permission is granted to anyone to use this software for any purpose,
35 including commercial applications, and to alter it and redistribute it
36 freely, subject to the following restrictions:
37
38 1. The origin of this software must not be misrepresented; you must not
39 claim that you wrote the original software. If you use this software
40 in a product, an acknowledgment in the product documentation would be
41 appreciated but is not required.
42 2. Altered source versions must be plainly marked as such, and must not be
43 misrepresented as being the original software.
44 3. This notice may not be removed or altered from any source distribution.
45
46 Jean-loup Gailly Mark Adler
47 jloup@gzip.org madler@alumni.caltech.edu
48
49
50 The data format used by the zlib library is described by RFCs (Request for
51 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
52 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
53 */
54
55 #ifndef ZLIB_H
56 #define ZLIB_H
57
58 #include "zconf.h"
59
60 #ifdef __cplusplus
61 extern "C" {
62 #endif
63
64 #define ZLIB_VERSION "1.2.11"
65 #define ZLIB_VERNUM 0x12b0
66 #define ZLIB_VER_MAJOR 1
67 #define ZLIB_VER_MINOR 2
68 #define ZLIB_VER_REVISION 11
69 #define ZLIB_VER_SUBREVISION 0
70
71 /*
72 The 'zlib' compression library provides in-memory compression and
73 decompression functions, including integrity checks of the uncompressed data.
74 This version of the library supports only one compression method (deflation)
75 but other algorithms will be added later and will have the same stream
76 interface.
77
78 Compression can be done in a single step if the buffers are large enough,
79 or can be done by repeated calls of the compression function. In the latter
80 case, the application must provide more input and/or consume the output
81 (providing more output space) before each call.
82
83 The compressed data format used by default by the in-memory functions is
84 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
85 around a deflate stream, which is itself documented in RFC 1951.
86
87 The library also supports reading and writing files in gzip (.gz) format
88 with an interface similar to that of stdio using the functions that start
89 with "gz". The gzip format is different from the zlib format. gzip is a
90 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
91
92 This library can optionally read and write gzip and raw deflate streams in
93 memory as well.
94
95 The zlib format was designed to be compact and fast for use in memory
96 and on communications channels. The gzip format was designed for single-
97 file compression on file systems, has a larger header than zlib to maintain
98 directory information, and uses a different, slower check method than zlib.
99
100 The library does not install any signal handler. The decoder checks
101 the consistency of the compressed data, so the library should never crash
102 even in the case of corrupted input.
103 */
104
105 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
106 typedef void (*free_func) OF((voidpf opaque, voidpf address));
107
108 struct internal_state;
109
110 typedef struct z_stream_s {
111 z_const Bytef *next_in; /* next input byte */
112 uInt avail_in; /* number of bytes available at next_in */
113 uLong total_in; /* total number of input bytes read so far */
114
115 Bytef *next_out; /* next output byte will go here */
116 uInt avail_out; /* remaining free space at next_out */
117 uLong total_out; /* total number of bytes output so far */
118
119 z_const char *msg; /* last error message, NULL if no error */
120 struct internal_state FAR *state; /* not visible by applications */
121
122 alloc_func zalloc; /* used to allocate the internal state */
123 free_func zfree; /* used to free the internal state */
124 voidpf opaque; /* private data object passed to zalloc and zfree */
125
126 int data_type; /* best guess about the data type: binary or text
127 for deflate, or the decoding state for inflate */
128 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */
129 uLong reserved; /* reserved for future use */
130 } z_stream;
131
132 typedef z_stream FAR *z_streamp;
133
134 /*
135 gzip header information passed to and from zlib routines. See RFC 1952
136 for more details on the meanings of these fields.
137 */
138 typedef struct gz_header_s {
139 int text; /* true if compressed data believed to be text */
140 uLong time; /* modification time */
141 int xflags; /* extra flags (not used when writing a gzip file) */
142 int os; /* operating system */
143 Bytef *extra; /* pointer to extra field or Z_NULL if none */
144 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
145 uInt extra_max; /* space at extra (only when reading header) */
146 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
147 uInt name_max; /* space at name (only when reading header) */
148 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
149 uInt comm_max; /* space at comment (only when reading header) */
150 int hcrc; /* true if there was or will be a header crc */
151 int done; /* true when done reading gzip header (not used
152 when writing a gzip file) */
153 } gz_header;
154
155 typedef gz_header FAR *gz_headerp;
156
157 /*
158 The application must update next_in and avail_in when avail_in has dropped
159 to zero. It must update next_out and avail_out when avail_out has dropped
160 to zero. The application must initialize zalloc, zfree and opaque before
161 calling the init function. All other fields are set by the compression
162 library and must not be updated by the application.
163
164 The opaque value provided by the application will be passed as the first
165 parameter for calls of zalloc and zfree. This can be useful for custom
166 memory management. The compression library attaches no meaning to the
167 opaque value.
168
169 zalloc must return Z_NULL if there is not enough memory for the object.
170 If zlib is used in a multi-threaded application, zalloc and zfree must be
171 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
172 Z_NULL on entry to the initialization function, they are set to internal
173 routines that use the standard library functions malloc() and free().
174
175 On 16-bit systems, the functions zalloc and zfree must be able to allocate
176 exactly 65536 bytes, but will not be required to allocate more than this if
177 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
178 returned by zalloc for objects of exactly 65536 bytes *must* have their
179 offset normalized to zero. The default allocation function provided by this
180 library ensures this (see zutil.c). To reduce memory requirements and avoid
181 any allocation of 64K objects, at the expense of compression ratio, compile
182 the library with -DMAX_WBITS=14 (see zconf.h).
183
184 The fields total_in and total_out can be used for statistics or progress
185 reports. After compression, total_in holds the total size of the
186 uncompressed data and may be saved for use by the decompressor (particularly
187 if the decompressor wants to decompress everything in a single step).
188 */
189
190 /* constants */
191
192 #define Z_NO_FLUSH 0
193 #define Z_PARTIAL_FLUSH 1
194 #define Z_SYNC_FLUSH 2
195 #define Z_FULL_FLUSH 3
196 #define Z_FINISH 4
197 #define Z_BLOCK 5
198 #define Z_TREES 6
199 /* Allowed flush values; see deflate() and inflate() below for details */
200
201 #define Z_OK 0
202 #define Z_STREAM_END 1
203 #define Z_NEED_DICT 2
204 #define Z_ERRNO (-1)
205 #define Z_STREAM_ERROR (-2)
206 #define Z_DATA_ERROR (-3)
207 #define Z_MEM_ERROR (-4)
208 #define Z_BUF_ERROR (-5)
209 #define Z_VERSION_ERROR (-6)
210 /* Return codes for the compression/decompression functions. Negative values
211 * are errors, positive values are used for special but normal events.
212 */
213
214 #define Z_NO_COMPRESSION 0
215 #define Z_BEST_SPEED 1
216 #define Z_BEST_COMPRESSION 9
217 #define Z_DEFAULT_COMPRESSION (-1)
218 /* compression levels */
219
220 #define Z_FILTERED 1
221 #define Z_HUFFMAN_ONLY 2
222 #define Z_RLE 3
223 #define Z_FIXED 4
224 #define Z_DEFAULT_STRATEGY 0
225 /* compression strategy; see deflateInit2() below for details */
226
227 #define Z_BINARY 0
228 #define Z_TEXT 1
229 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
230 #define Z_UNKNOWN 2
231 /* Possible values of the data_type field for deflate() */
232
233 #define Z_DEFLATED 8
234 /* The deflate compression method (the only one supported in this version) */
235
236 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
237
238 #define zlib_version zlibVersion()
239 /* for compatibility with versions < 1.0.2 */
240
241
242 /* basic functions */
243
244 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
245 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
246 If the first character differs, the library code actually used is not
247 compatible with the zlib.h header file used by the application. This check
248 is automatically made by deflateInit and inflateInit.
249 */
250
251 /*
252 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
253
254 Initializes the internal stream state for compression. The fields
255 zalloc, zfree and opaque must be initialized before by the caller. If
256 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
257 allocation functions.
258
259 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
260 1 gives best speed, 9 gives best compression, 0 gives no compression at all
261 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
262 requests a default compromise between speed and compression (currently
263 equivalent to level 6).
264
265 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
266 memory, Z_STREAM_ERROR if level is not a valid compression level, or
267 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
268 with the version assumed by the caller (ZLIB_VERSION). msg is set to null
269 if there is no error message. deflateInit does not perform any compression:
270 this will be done by deflate().
271 */
272
273
274 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
275 /*
276 deflate compresses as much data as possible, and stops when the input
277 buffer becomes empty or the output buffer becomes full. It may introduce
278 some output latency (reading input without producing any output) except when
279 forced to flush.
280
281 The detailed semantics are as follows. deflate performs one or both of the
282 following actions:
283
284 - Compress more input starting at next_in and update next_in and avail_in
285 accordingly. If not all input can be processed (because there is not
286 enough room in the output buffer), next_in and avail_in are updated and
287 processing will resume at this point for the next call of deflate().
288
289 - Generate more output starting at next_out and update next_out and avail_out
290 accordingly. This action is forced if the parameter flush is non zero.
291 Forcing flush frequently degrades the compression ratio, so this parameter
292 should be set only when necessary. Some output may be provided even if
293 flush is zero.
294
295 Before the call of deflate(), the application should ensure that at least
296 one of the actions is possible, by providing more input and/or consuming more
297 output, and updating avail_in or avail_out accordingly; avail_out should
298 never be zero before the call. The application can consume the compressed
299 output when it wants, for example when the output buffer is full (avail_out
300 == 0), or after each call of deflate(). If deflate returns Z_OK and with
301 zero avail_out, it must be called again after making room in the output
302 buffer because there might be more output pending. See deflatePending(),
303 which can be used if desired to determine whether or not there is more ouput
304 in that case.
305
306 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
307 decide how much data to accumulate before producing output, in order to
308 maximize compression.
309
310 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
311 flushed to the output buffer and the output is aligned on a byte boundary, so
312 that the decompressor can get all input data available so far. (In
313 particular avail_in is zero after the call if enough output space has been
314 provided before the call.) Flushing may degrade compression for some
315 compression algorithms and so it should be used only when necessary. This
316 completes the current deflate block and follows it with an empty stored block
317 that is three bits plus filler bits to the next byte, followed by four bytes
318 (00 00 ff ff).
319
320 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
321 output buffer, but the output is not aligned to a byte boundary. All of the
322 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
323 This completes the current deflate block and follows it with an empty fixed
324 codes block that is 10 bits long. This assures that enough bytes are output
325 in order for the decompressor to finish the block before the empty fixed
326 codes block.
327
328 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
329 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
330 seven bits of the current block are held to be written as the next byte after
331 the next deflate block is completed. In this case, the decompressor may not
332 be provided enough bits at this point in order to complete decompression of
333 the data provided so far to the compressor. It may need to wait for the next
334 block to be emitted. This is for advanced applications that need to control
335 the emission of deflate blocks.
336
337 If flush is set to Z_FULL_FLUSH, all output is flushed as with
338 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
339 restart from this point if previous compressed data has been damaged or if
340 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
341 compression.
342
343 If deflate returns with avail_out == 0, this function must be called again
344 with the same value of the flush parameter and more output space (updated
345 avail_out), until the flush is complete (deflate returns with non-zero
346 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
347 avail_out is greater than six to avoid repeated flush markers due to
348 avail_out == 0 on return.
349
350 If the parameter flush is set to Z_FINISH, pending input is processed,
351 pending output is flushed and deflate returns with Z_STREAM_END if there was
352 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this
353 function must be called again with Z_FINISH and more output space (updated
354 avail_out) but no more input data, until it returns with Z_STREAM_END or an
355 error. After deflate has returned Z_STREAM_END, the only possible operations
356 on the stream are deflateReset or deflateEnd.
357
358 Z_FINISH can be used in the first deflate call after deflateInit if all the
359 compression is to be done in a single step. In order to complete in one
360 call, avail_out must be at least the value returned by deflateBound (see
361 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough
362 output space is provided, deflate will not return Z_STREAM_END, and it must
363 be called again as described above.
364
365 deflate() sets strm->adler to the Adler-32 checksum of all input read
366 so far (that is, total_in bytes). If a gzip stream is being generated, then
367 strm->adler will be the CRC-32 checksum of the input read so far. (See
368 deflateInit2 below.)
369
370 deflate() may update strm->data_type if it can make a good guess about
371 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is
372 considered binary. This field is only for information purposes and does not
373 affect the compression algorithm in any manner.
374
375 deflate() returns Z_OK if some progress has been made (more input
376 processed or more output produced), Z_STREAM_END if all input has been
377 consumed and all output has been produced (only when flush is set to
378 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
379 if next_in or next_out was Z_NULL or the state was inadvertently written over
380 by the application), or Z_BUF_ERROR if no progress is possible (for example
381 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
382 deflate() can be called again with more input and more output space to
383 continue compressing.
384 */
385
386
387 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
388 /*
389 All dynamically allocated data structures for this stream are freed.
390 This function discards any unprocessed input and does not flush any pending
391 output.
392
393 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
394 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
395 prematurely (some input or output was discarded). In the error case, msg
396 may be set but then points to a static string (which must not be
397 deallocated).
398 */
399
400
401 /*
402 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
403
404 Initializes the internal stream state for decompression. The fields
405 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
406 the caller. In the current version of inflate, the provided input is not
407 read or consumed. The allocation of a sliding window will be deferred to
408 the first call of inflate (if the decompression does not complete on the
409 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates
410 them to use default allocation functions.
411
412 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
413 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
414 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
415 invalid, such as a null pointer to the structure. msg is set to null if
416 there is no error message. inflateInit does not perform any decompression.
417 Actual decompression will be done by inflate(). So next_in, and avail_in,
418 next_out, and avail_out are unused and unchanged. The current
419 implementation of inflateInit() does not process any header information --
420 that is deferred until inflate() is called.
421 */
422
423
424 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
425 /*
426 inflate decompresses as much data as possible, and stops when the input
427 buffer becomes empty or the output buffer becomes full. It may introduce
428 some output latency (reading input without producing any output) except when
429 forced to flush.
430
431 The detailed semantics are as follows. inflate performs one or both of the
432 following actions:
433
434 - Decompress more input starting at next_in and update next_in and avail_in
435 accordingly. If not all input can be processed (because there is not
436 enough room in the output buffer), then next_in and avail_in are updated
437 accordingly, and processing will resume at this point for the next call of
438 inflate().
439
440 - Generate more output starting at next_out and update next_out and avail_out
441 accordingly. inflate() provides as much output as possible, until there is
442 no more input data or no more space in the output buffer (see below about
443 the flush parameter).
444
445 Before the call of inflate(), the application should ensure that at least
446 one of the actions is possible, by providing more input and/or consuming more
447 output, and updating the next_* and avail_* values accordingly. If the
448 caller of inflate() does not provide both available input and available
449 output space, it is possible that there will be no progress made. The
450 application can consume the uncompressed output when it wants, for example
451 when the output buffer is full (avail_out == 0), or after each call of
452 inflate(). If inflate returns Z_OK and with zero avail_out, it must be
453 called again after making room in the output buffer because there might be
454 more output pending.
455
456 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
457 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
458 output as possible to the output buffer. Z_BLOCK requests that inflate()
459 stop if and when it gets to the next deflate block boundary. When decoding
460 the zlib or gzip format, this will cause inflate() to return immediately
461 after the header and before the first block. When doing a raw inflate,
462 inflate() will go ahead and process the first block, and will return when it
463 gets to the end of that block, or when it runs out of data.
464
465 The Z_BLOCK option assists in appending to or combining deflate streams.
466 To assist in this, on return inflate() always sets strm->data_type to the
467 number of unused bits in the last byte taken from strm->next_in, plus 64 if
468 inflate() is currently decoding the last block in the deflate stream, plus
469 128 if inflate() returned immediately after decoding an end-of-block code or
470 decoding the complete header up to just before the first byte of the deflate
471 stream. The end-of-block will not be indicated until all of the uncompressed
472 data from that block has been written to strm->next_out. The number of
473 unused bits may in general be greater than seven, except when bit 7 of
474 data_type is set, in which case the number of unused bits will be less than
475 eight. data_type is set as noted here every time inflate() returns for all
476 flush options, and so can be used to determine the amount of currently
477 consumed input in bits.
478
479 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
480 end of each deflate block header is reached, before any actual data in that
481 block is decoded. This allows the caller to determine the length of the
482 deflate block header for later use in random access within a deflate block.
483 256 is added to the value of strm->data_type when inflate() returns
484 immediately after reaching the end of the deflate block header.
485
486 inflate() should normally be called until it returns Z_STREAM_END or an
487 error. However if all decompression is to be performed in a single step (a
488 single call of inflate), the parameter flush should be set to Z_FINISH. In
489 this case all pending input is processed and all pending output is flushed;
490 avail_out must be large enough to hold all of the uncompressed data for the
491 operation to complete. (The size of the uncompressed data may have been
492 saved by the compressor for this purpose.) The use of Z_FINISH is not
493 required to perform an inflation in one step. However it may be used to
494 inform inflate that a faster approach can be used for the single inflate()
495 call. Z_FINISH also informs inflate to not maintain a sliding window if the
496 stream completes, which reduces inflate's memory footprint. If the stream
497 does not complete, either because not all of the stream is provided or not
498 enough output space is provided, then a sliding window will be allocated and
499 inflate() can be called again to continue the operation as if Z_NO_FLUSH had
500 been used.
501
502 In this implementation, inflate() always flushes as much output as
503 possible to the output buffer, and always uses the faster approach on the
504 first call. So the effects of the flush parameter in this implementation are
505 on the return value of inflate() as noted below, when inflate() returns early
506 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
507 memory for a sliding window when Z_FINISH is used.
508
509 If a preset dictionary is needed after this call (see inflateSetDictionary
510 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
511 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
512 strm->adler to the Adler-32 checksum of all output produced so far (that is,
513 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
514 below. At the end of the stream, inflate() checks that its computed Adler-32
515 checksum is equal to that saved by the compressor and returns Z_STREAM_END
516 only if the checksum is correct.
517
518 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
519 deflate data. The header type is detected automatically, if requested when
520 initializing with inflateInit2(). Any information contained in the gzip
521 header is not retained unless inflateGetHeader() is used. When processing
522 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
523 produced so far. The CRC-32 is checked against the gzip trailer, as is the
524 uncompressed length, modulo 2^32.
525
526 inflate() returns Z_OK if some progress has been made (more input processed
527 or more output produced), Z_STREAM_END if the end of the compressed data has
528 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
529 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
530 corrupted (input stream not conforming to the zlib format or incorrect check
531 value, in which case strm->msg points to a string with a more specific
532 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
533 next_in or next_out was Z_NULL, or the state was inadvertently written over
534 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
535 if no progress was possible or if there was not enough room in the output
536 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
537 inflate() can be called again with more input and more output space to
538 continue decompressing. If Z_DATA_ERROR is returned, the application may
539 then call inflateSync() to look for a good compression block if a partial
540 recovery of the data is to be attempted.
541 */
542
543
544 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
545 /*
546 All dynamically allocated data structures for this stream are freed.
547 This function discards any unprocessed input and does not flush any pending
548 output.
549
550 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
551 was inconsistent.
552 */
553
554
555 /* Advanced functions */
556
557 /*
558 The following functions are needed only in some special applications.
559 */
560
561 /*
562 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
563 int level,
564 int method,
565 int windowBits,
566 int memLevel,
567 int strategy));
568
569 This is another version of deflateInit with more compression options. The
570 fields next_in, zalloc, zfree and opaque must be initialized before by the
571 caller.
572
573 The method parameter is the compression method. It must be Z_DEFLATED in
574 this version of the library.
575
576 The windowBits parameter is the base two logarithm of the window size
577 (the size of the history buffer). It should be in the range 8..15 for this
578 version of the library. Larger values of this parameter result in better
579 compression at the expense of memory usage. The default value is 15 if
580 deflateInit is used instead.
581
582 For the current implementation of deflate(), a windowBits value of 8 (a
583 window size of 256 bytes) is not supported. As a result, a request for 8
584 will result in 9 (a 512-byte window). In that case, providing 8 to
585 inflateInit2() will result in an error when the zlib header with 9 is
586 checked against the initialization of inflate(). The remedy is to not use 8
587 with deflateInit2() with this initialization, or at least in that case use 9
588 with inflateInit2().
589
590 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
591 determines the window size. deflate() will then generate raw deflate data
592 with no zlib header or trailer, and will not compute a check value.
593
594 windowBits can also be greater than 15 for optional gzip encoding. Add
595 16 to windowBits to write a simple gzip header and trailer around the
596 compressed data instead of a zlib wrapper. The gzip header will have no
597 file name, no extra data, no comment, no modification time (set to zero), no
598 header crc, and the operating system will be set to the appropriate value,
599 if the operating system was determined at compile time. If a gzip stream is
600 being written, strm->adler is a CRC-32 instead of an Adler-32.
601
602 For raw deflate or gzip encoding, a request for a 256-byte window is
603 rejected as invalid, since only the zlib header provides a means of
604 transmitting the window size to the decompressor.
605
606 The memLevel parameter specifies how much memory should be allocated
607 for the internal compression state. memLevel=1 uses minimum memory but is
608 slow and reduces compression ratio; memLevel=9 uses maximum memory for
609 optimal speed. The default value is 8. See zconf.h for total memory usage
610 as a function of windowBits and memLevel.
611
612 The strategy parameter is used to tune the compression algorithm. Use the
613 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
614 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
615 string match), or Z_RLE to limit match distances to one (run-length
616 encoding). Filtered data consists mostly of small values with a somewhat
617 random distribution. In this case, the compression algorithm is tuned to
618 compress them better. The effect of Z_FILTERED is to force more Huffman
619 coding and less string matching; it is somewhat intermediate between
620 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
621 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
622 strategy parameter only affects the compression ratio but not the
623 correctness of the compressed output even if it is not set appropriately.
624 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
625 decoder for special applications.
626
627 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
628 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
629 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
630 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
631 set to null if there is no error message. deflateInit2 does not perform any
632 compression: this will be done by deflate().
633 */
634
635 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
636 const Bytef *dictionary,
637 uInt dictLength));
638 /*
639 Initializes the compression dictionary from the given byte sequence
640 without producing any compressed output. When using the zlib format, this
641 function must be called immediately after deflateInit, deflateInit2 or
642 deflateReset, and before any call of deflate. When doing raw deflate, this
643 function must be called either before any call of deflate, or immediately
644 after the completion of a deflate block, i.e. after all input has been
645 consumed and all output has been delivered when using any of the flush
646 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
647 compressor and decompressor must use exactly the same dictionary (see
648 inflateSetDictionary).
649
650 The dictionary should consist of strings (byte sequences) that are likely
651 to be encountered later in the data to be compressed, with the most commonly
652 used strings preferably put towards the end of the dictionary. Using a
653 dictionary is most useful when the data to be compressed is short and can be
654 predicted with good accuracy; the data can then be compressed better than
655 with the default empty dictionary.
656
657 Depending on the size of the compression data structures selected by
658 deflateInit or deflateInit2, a part of the dictionary may in effect be
659 discarded, for example if the dictionary is larger than the window size
660 provided in deflateInit or deflateInit2. Thus the strings most likely to be
661 useful should be put at the end of the dictionary, not at the front. In
662 addition, the current implementation of deflate will use at most the window
663 size minus 262 bytes of the provided dictionary.
664
665 Upon return of this function, strm->adler is set to the Adler-32 value
666 of the dictionary; the decompressor may later use this value to determine
667 which dictionary has been used by the compressor. (The Adler-32 value
668 applies to the whole dictionary even if only a subset of the dictionary is
669 actually used by the compressor.) If a raw deflate was requested, then the
670 Adler-32 value is not computed and strm->adler is not set.
671
672 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
673 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
674 inconsistent (for example if deflate has already been called for this stream
675 or if not at a block boundary for raw deflate). deflateSetDictionary does
676 not perform any compression: this will be done by deflate().
677 */
678
679 ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm,
680 Bytef *dictionary,
681 uInt *dictLength));
682 /*
683 Returns the sliding dictionary being maintained by deflate. dictLength is
684 set to the number of bytes in the dictionary, and that many bytes are copied
685 to dictionary. dictionary must have enough space, where 32768 bytes is
686 always enough. If deflateGetDictionary() is called with dictionary equal to
687 Z_NULL, then only the dictionary length is returned, and nothing is copied.
688 Similary, if dictLength is Z_NULL, then it is not set.
689
690 deflateGetDictionary() may return a length less than the window size, even
691 when more than the window size in input has been provided. It may return up
692 to 258 bytes less in that case, due to how zlib's implementation of deflate
693 manages the sliding window and lookahead for matches, where matches can be
694 up to 258 bytes long. If the application needs the last window-size bytes of
695 input, then that would need to be saved by the application outside of zlib.
696
697 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
698 stream state is inconsistent.
699 */
700
701 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
702 z_streamp source));
703 /*
704 Sets the destination stream as a complete copy of the source stream.
705
706 This function can be useful when several compression strategies will be
707 tried, for example when there are several ways of pre-processing the input
708 data with a filter. The streams that will be discarded should then be freed
709 by calling deflateEnd. Note that deflateCopy duplicates the internal
710 compression state which can be quite large, so this strategy is slow and can
711 consume lots of memory.
712
713 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
714 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
715 (such as zalloc being Z_NULL). msg is left unchanged in both source and
716 destination.
717 */
718
719 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
720 /*
721 This function is equivalent to deflateEnd followed by deflateInit, but
722 does not free and reallocate the internal compression state. The stream
723 will leave the compression level and any other attributes that may have been
724 set unchanged.
725
726 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
727 stream state was inconsistent (such as zalloc or state being Z_NULL).
728 */
729
730 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
731 int level,
732 int strategy));
733 /*
734 Dynamically update the compression level and compression strategy. The
735 interpretation of level and strategy is as in deflateInit2(). This can be
736 used to switch between compression and straight copy of the input data, or
737 to switch to a different kind of input data requiring a different strategy.
738 If the compression approach (which is a function of the level) or the
739 strategy is changed, and if any input has been consumed in a previous
740 deflate() call, then the input available so far is compressed with the old
741 level and strategy using deflate(strm, Z_BLOCK). There are three approaches
742 for the compression levels 0, 1..3, and 4..9 respectively. The new level
743 and strategy will take effect at the next call of deflate().
744
745 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
746 not have enough output space to complete, then the parameter change will not
747 take effect. In this case, deflateParams() can be called again with the
748 same parameters and more output space to try again.
749
750 In order to assure a change in the parameters on the first try, the
751 deflate stream should be flushed using deflate() with Z_BLOCK or other flush
752 request until strm.avail_out is not zero, before calling deflateParams().
753 Then no more input data should be provided before the deflateParams() call.
754 If this is done, the old level and strategy will be applied to the data
755 compressed before deflateParams(), and the new level and strategy will be
756 applied to the the data compressed after deflateParams().
757
758 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
759 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
760 there was not enough output space to complete the compression of the
761 available input data before a change in the strategy or approach. Note that
762 in the case of a Z_BUF_ERROR, the parameters are not changed. A return
763 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
764 retried with more output space.
765 */
766
767 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
768 int good_length,
769 int max_lazy,
770 int nice_length,
771 int max_chain));
772 /*
773 Fine tune deflate's internal compression parameters. This should only be
774 used by someone who understands the algorithm used by zlib's deflate for
775 searching for the best matching string, and even then only by the most
776 fanatic optimizer trying to squeeze out the last compressed bit for their
777 specific input data. Read the deflate.c source code for the meaning of the
778 max_lazy, good_length, nice_length, and max_chain parameters.
779
780 deflateTune() can be called after deflateInit() or deflateInit2(), and
781 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
782 */
783
784 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
785 uLong sourceLen));
786 /*
787 deflateBound() returns an upper bound on the compressed size after
788 deflation of sourceLen bytes. It must be called after deflateInit() or
789 deflateInit2(), and after deflateSetHeader(), if used. This would be used
790 to allocate an output buffer for deflation in a single pass, and so would be
791 called before deflate(). If that first deflate() call is provided the
792 sourceLen input bytes, an output buffer allocated to the size returned by
793 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
794 to return Z_STREAM_END. Note that it is possible for the compressed size to
795 be larger than the value returned by deflateBound() if flush options other
796 than Z_FINISH or Z_NO_FLUSH are used.
797 */
798
799 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
800 unsigned *pending,
801 int *bits));
802 /*
803 deflatePending() returns the number of bytes and bits of output that have
804 been generated, but not yet provided in the available output. The bytes not
805 provided would be due to the available output space having being consumed.
806 The number of bits of output not provided are between 0 and 7, where they
807 await more bits to join them in order to fill out a full byte. If pending
808 or bits are Z_NULL, then those values are not set.
809
810 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
811 stream state was inconsistent.
812 */
813
814 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
815 int bits,
816 int value));
817 /*
818 deflatePrime() inserts bits in the deflate output stream. The intent
819 is that this function is used to start off the deflate output with the bits
820 leftover from a previous deflate stream when appending to it. As such, this
821 function can only be used for raw deflate, and must be used before the first
822 deflate() call after a deflateInit2() or deflateReset(). bits must be less
823 than or equal to 16, and that many of the least significant bits of value
824 will be inserted in the output.
825
826 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
827 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
828 source stream state was inconsistent.
829 */
830
831 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
832 gz_headerp head));
833 /*
834 deflateSetHeader() provides gzip header information for when a gzip
835 stream is requested by deflateInit2(). deflateSetHeader() may be called
836 after deflateInit2() or deflateReset() and before the first call of
837 deflate(). The text, time, os, extra field, name, and comment information
838 in the provided gz_header structure are written to the gzip header (xflag is
839 ignored -- the extra flags are set according to the compression level). The
840 caller must assure that, if not Z_NULL, name and comment are terminated with
841 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
842 available there. If hcrc is true, a gzip header crc is included. Note that
843 the current versions of the command-line version of gzip (up through version
844 1.3.x) do not support header crc's, and will report that it is a "multi-part
845 gzip file" and give up.
846
847 If deflateSetHeader is not used, the default gzip header has text false,
848 the time set to zero, and os set to 255, with no extra, name, or comment
849 fields. The gzip header is returned to the default state by deflateReset().
850
851 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
852 stream state was inconsistent.
853 */
854
855 /*
856 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
857 int windowBits));
858
859 This is another version of inflateInit with an extra parameter. The
860 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
861 before by the caller.
862
863 The windowBits parameter is the base two logarithm of the maximum window
864 size (the size of the history buffer). It should be in the range 8..15 for
865 this version of the library. The default value is 15 if inflateInit is used
866 instead. windowBits must be greater than or equal to the windowBits value
867 provided to deflateInit2() while compressing, or it must be equal to 15 if
868 deflateInit2() was not used. If a compressed stream with a larger window
869 size is given as input, inflate() will return with the error code
870 Z_DATA_ERROR instead of trying to allocate a larger window.
871
872 windowBits can also be zero to request that inflate use the window size in
873 the zlib header of the compressed stream.
874
875 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
876 determines the window size. inflate() will then process raw deflate data,
877 not looking for a zlib or gzip header, not generating a check value, and not
878 looking for any check values for comparison at the end of the stream. This
879 is for use with other formats that use the deflate compressed data format
880 such as zip. Those formats provide their own check values. If a custom
881 format is developed using the raw deflate format for compressed data, it is
882 recommended that a check value such as an Adler-32 or a CRC-32 be applied to
883 the uncompressed data as is done in the zlib, gzip, and zip formats. For
884 most applications, the zlib format should be used as is. Note that comments
885 above on the use in deflateInit2() applies to the magnitude of windowBits.
886
887 windowBits can also be greater than 15 for optional gzip decoding. Add
888 32 to windowBits to enable zlib and gzip decoding with automatic header
889 detection, or add 16 to decode only the gzip format (the zlib format will
890 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
891 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see
892 below), inflate() will not automatically decode concatenated gzip streams.
893 inflate() will return Z_STREAM_END at the end of the gzip stream. The state
894 would need to be reset to continue decoding a subsequent gzip stream.
895
896 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
897 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
898 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
899 invalid, such as a null pointer to the structure. msg is set to null if
900 there is no error message. inflateInit2 does not perform any decompression
901 apart from possibly reading the zlib header if present: actual decompression
902 will be done by inflate(). (So next_in and avail_in may be modified, but
903 next_out and avail_out are unused and unchanged.) The current implementation
904 of inflateInit2() does not process any header information -- that is
905 deferred until inflate() is called.
906 */
907
908 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
909 const Bytef *dictionary,
910 uInt dictLength));
911 /*
912 Initializes the decompression dictionary from the given uncompressed byte
913 sequence. This function must be called immediately after a call of inflate,
914 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
915 can be determined from the Adler-32 value returned by that call of inflate.
916 The compressor and decompressor must use exactly the same dictionary (see
917 deflateSetDictionary). For raw inflate, this function can be called at any
918 time to set the dictionary. If the provided dictionary is smaller than the
919 window and there is already data in the window, then the provided dictionary
920 will amend what's there. The application must insure that the dictionary
921 that was used for compression is provided.
922
923 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
924 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
925 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
926 expected one (incorrect Adler-32 value). inflateSetDictionary does not
927 perform any decompression: this will be done by subsequent calls of
928 inflate().
929 */
930
931 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
932 Bytef *dictionary,
933 uInt *dictLength));
934 /*
935 Returns the sliding dictionary being maintained by inflate. dictLength is
936 set to the number of bytes in the dictionary, and that many bytes are copied
937 to dictionary. dictionary must have enough space, where 32768 bytes is
938 always enough. If inflateGetDictionary() is called with dictionary equal to
939 Z_NULL, then only the dictionary length is returned, and nothing is copied.
940 Similary, if dictLength is Z_NULL, then it is not set.
941
942 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
943 stream state is inconsistent.
944 */
945
946 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
947 /*
948 Skips invalid compressed data until a possible full flush point (see above
949 for the description of deflate with Z_FULL_FLUSH) can be found, or until all
950 available input is skipped. No output is provided.
951
952 inflateSync searches for a 00 00 FF FF pattern in the compressed data.
953 All full flush points have this pattern, but not all occurrences of this
954 pattern are full flush points.
955
956 inflateSync returns Z_OK if a possible full flush point has been found,
957 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
958 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
959 In the success case, the application may save the current current value of
960 total_in which indicates where valid compressed data was found. In the
961 error case, the application may repeatedly call inflateSync, providing more
962 input each time, until success or end of the input data.
963 */
964
965 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
966 z_streamp source));
967 /*
968 Sets the destination stream as a complete copy of the source stream.
969
970 This function can be useful when randomly accessing a large stream. The
971 first pass through the stream can periodically record the inflate state,
972 allowing restarting inflate at those points when randomly accessing the
973 stream.
974
975 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
976 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
977 (such as zalloc being Z_NULL). msg is left unchanged in both source and
978 destination.
979 */
980
981 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
982 /*
983 This function is equivalent to inflateEnd followed by inflateInit,
984 but does not free and reallocate the internal decompression state. The
985 stream will keep attributes that may have been set by inflateInit2.
986
987 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
988 stream state was inconsistent (such as zalloc or state being Z_NULL).
989 */
990
991 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
992 int windowBits));
993 /*
994 This function is the same as inflateReset, but it also permits changing
995 the wrap and window size requests. The windowBits parameter is interpreted
996 the same as it is for inflateInit2. If the window size is changed, then the
997 memory allocated for the window is freed, and the window will be reallocated
998 by inflate() if needed.
999
1000 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
1001 stream state was inconsistent (such as zalloc or state being Z_NULL), or if
1002 the windowBits parameter is invalid.
1003 */
1004
1005 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
1006 int bits,
1007 int value));
1008 /*
1009 This function inserts bits in the inflate input stream. The intent is
1010 that this function is used to start inflating at a bit position in the
1011 middle of a byte. The provided bits will be used before any bytes are used
1012 from next_in. This function should only be used with raw inflate, and
1013 should be used before the first inflate() call after inflateInit2() or
1014 inflateReset(). bits must be less than or equal to 16, and that many of the
1015 least significant bits of value will be inserted in the input.
1016
1017 If bits is negative, then the input stream bit buffer is emptied. Then
1018 inflatePrime() can be called again to put bits in the buffer. This is used
1019 to clear out bits leftover after feeding inflate a block description prior
1020 to feeding inflate codes.
1021
1022 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
1023 stream state was inconsistent.
1024 */
1025
1026 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
1027 /*
1028 This function returns two values, one in the lower 16 bits of the return
1029 value, and the other in the remaining upper bits, obtained by shifting the
1030 return value down 16 bits. If the upper value is -1 and the lower value is
1031 zero, then inflate() is currently decoding information outside of a block.
1032 If the upper value is -1 and the lower value is non-zero, then inflate is in
1033 the middle of a stored block, with the lower value equaling the number of
1034 bytes from the input remaining to copy. If the upper value is not -1, then
1035 it is the number of bits back from the current bit position in the input of
1036 the code (literal or length/distance pair) currently being processed. In
1037 that case the lower value is the number of bytes already emitted for that
1038 code.
1039
1040 A code is being processed if inflate is waiting for more input to complete
1041 decoding of the code, or if it has completed decoding but is waiting for
1042 more output space to write the literal or match data.
1043
1044 inflateMark() is used to mark locations in the input data for random
1045 access, which may be at bit positions, and to note those cases where the
1046 output of a code may span boundaries of random access blocks. The current
1047 location in the input stream can be determined from avail_in and data_type
1048 as noted in the description for the Z_BLOCK flush parameter for inflate.
1049
1050 inflateMark returns the value noted above, or -65536 if the provided
1051 source stream state was inconsistent.
1052 */
1053
1054 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
1055 gz_headerp head));
1056 /*
1057 inflateGetHeader() requests that gzip header information be stored in the
1058 provided gz_header structure. inflateGetHeader() may be called after
1059 inflateInit2() or inflateReset(), and before the first call of inflate().
1060 As inflate() processes the gzip stream, head->done is zero until the header
1061 is completed, at which time head->done is set to one. If a zlib stream is
1062 being decoded, then head->done is set to -1 to indicate that there will be
1063 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
1064 used to force inflate() to return immediately after header processing is
1065 complete and before any actual data is decompressed.
1066
1067 The text, time, xflags, and os fields are filled in with the gzip header
1068 contents. hcrc is set to true if there is a header CRC. (The header CRC
1069 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
1070 contains the maximum number of bytes to write to extra. Once done is true,
1071 extra_len contains the actual extra field length, and extra contains the
1072 extra field, or that field truncated if extra_max is less than extra_len.
1073 If name is not Z_NULL, then up to name_max characters are written there,
1074 terminated with a zero unless the length is greater than name_max. If
1075 comment is not Z_NULL, then up to comm_max characters are written there,
1076 terminated with a zero unless the length is greater than comm_max. When any
1077 of extra, name, or comment are not Z_NULL and the respective field is not
1078 present in the header, then that field is set to Z_NULL to signal its
1079 absence. This allows the use of deflateSetHeader() with the returned
1080 structure to duplicate the header. However if those fields are set to
1081 allocated memory, then the application will need to save those pointers
1082 elsewhere so that they can be eventually freed.
1083
1084 If inflateGetHeader is not used, then the header information is simply
1085 discarded. The header is always checked for validity, including the header
1086 CRC if present. inflateReset() will reset the process to discard the header
1087 information. The application would need to call inflateGetHeader() again to
1088 retrieve the header from the next gzip stream.
1089
1090 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1091 stream state was inconsistent.
1092 */
1093
1094 /*
1095 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1096 unsigned char FAR *window));
1097
1098 Initialize the internal stream state for decompression using inflateBack()
1099 calls. The fields zalloc, zfree and opaque in strm must be initialized
1100 before the call. If zalloc and zfree are Z_NULL, then the default library-
1101 derived memory allocation routines are used. windowBits is the base two
1102 logarithm of the window size, in the range 8..15. window is a caller
1103 supplied buffer of that size. Except for special applications where it is
1104 assured that deflate was used with small window sizes, windowBits must be 15
1105 and a 32K byte window must be supplied to be able to decompress general
1106 deflate streams.
1107
1108 See inflateBack() for the usage of these routines.
1109
1110 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1111 the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1112 allocated, or Z_VERSION_ERROR if the version of the library does not match
1113 the version of the header file.
1114 */
1115
1116 typedef unsigned (*in_func) OF((void FAR *,
1117 z_const unsigned char FAR * FAR *));
1118 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1119
1120 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1121 in_func in, void FAR *in_desc,
1122 out_func out, void FAR *out_desc));
1123 /*
1124 inflateBack() does a raw inflate with a single call using a call-back
1125 interface for input and output. This is potentially more efficient than
1126 inflate() for file i/o applications, in that it avoids copying between the
1127 output and the sliding window by simply making the window itself the output
1128 buffer. inflate() can be faster on modern CPUs when used with large
1129 buffers. inflateBack() trusts the application to not change the output
1130 buffer passed by the output function, at least until inflateBack() returns.
1131
1132 inflateBackInit() must be called first to allocate the internal state
1133 and to initialize the state with the user-provided window buffer.
1134 inflateBack() may then be used multiple times to inflate a complete, raw
1135 deflate stream with each call. inflateBackEnd() is then called to free the
1136 allocated state.
1137
1138 A raw deflate stream is one with no zlib or gzip header or trailer.
1139 This routine would normally be used in a utility that reads zip or gzip
1140 files and writes out uncompressed files. The utility would decode the
1141 header and process the trailer on its own, hence this routine expects only
1142 the raw deflate stream to decompress. This is different from the default
1143 behavior of inflate(), which expects a zlib header and trailer around the
1144 deflate stream.
1145
1146 inflateBack() uses two subroutines supplied by the caller that are then
1147 called by inflateBack() for input and output. inflateBack() calls those
1148 routines until it reads a complete deflate stream and writes out all of the
1149 uncompressed data, or until it encounters an error. The function's
1150 parameters and return types are defined above in the in_func and out_func
1151 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1152 number of bytes of provided input, and a pointer to that input in buf. If
1153 there is no input available, in() must return zero -- buf is ignored in that
1154 case -- and inflateBack() will return a buffer error. inflateBack() will
1155 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
1156 out() should return zero on success, or non-zero on failure. If out()
1157 returns non-zero, inflateBack() will return with an error. Neither in() nor
1158 out() are permitted to change the contents of the window provided to
1159 inflateBackInit(), which is also the buffer that out() uses to write from.
1160 The length written by out() will be at most the window size. Any non-zero
1161 amount of input may be provided by in().
1162
1163 For convenience, inflateBack() can be provided input on the first call by
1164 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1165 in() will be called. Therefore strm->next_in must be initialized before
1166 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1167 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1168 must also be initialized, and then if strm->avail_in is not zero, input will
1169 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1170
1171 The in_desc and out_desc parameters of inflateBack() is passed as the
1172 first parameter of in() and out() respectively when they are called. These
1173 descriptors can be optionally used to pass any information that the caller-
1174 supplied in() and out() functions need to do their job.
1175
1176 On return, inflateBack() will set strm->next_in and strm->avail_in to
1177 pass back any unused input that was provided by the last in() call. The
1178 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1179 if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1180 in the deflate stream (in which case strm->msg is set to indicate the nature
1181 of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1182 In the case of Z_BUF_ERROR, an input or output error can be distinguished
1183 using strm->next_in which will be Z_NULL only if in() returned an error. If
1184 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1185 non-zero. (in() will always be called before out(), so strm->next_in is
1186 assured to be defined if out() returns non-zero.) Note that inflateBack()
1187 cannot return Z_OK.
1188 */
1189
1190 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1191 /*
1192 All memory allocated by inflateBackInit() is freed.
1193
1194 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1195 state was inconsistent.
1196 */
1197
1198 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1199 /* Return flags indicating compile-time options.
1200
1201 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1202 1.0: size of uInt
1203 3.2: size of uLong
1204 5.4: size of voidpf (pointer)
1205 7.6: size of z_off_t
1206
1207 Compiler, assembler, and debug options:
1208 8: ZLIB_DEBUG
1209 9: ASMV or ASMINF -- use ASM code
1210 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1211 11: 0 (reserved)
1212
1213 One-time table building (smaller code, but not thread-safe if true):
1214 12: BUILDFIXED -- build static block decoding tables when needed
1215 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1216 14,15: 0 (reserved)
1217
1218 Library content (indicates missing functionality):
1219 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1220 deflate code when not needed)
1221 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1222 and decode gzip streams (to avoid linking crc code)
1223 18-19: 0 (reserved)
1224
1225 Operation variations (changes in library functionality):
1226 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1227 21: FASTEST -- deflate algorithm with only one, lowest compression level
1228 22,23: 0 (reserved)
1229
1230 The sprintf variant used by gzprintf (zero is best):
1231 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1232 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1233 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1234
1235 Remainder:
1236 27-31: 0 (reserved)
1237 */
1238
1239 #ifndef Z_SOLO
1240
1241 /* utility functions */
1242
1243 /*
1244 The following utility functions are implemented on top of the basic
1245 stream-oriented functions. To simplify the interface, some default options
1246 are assumed (compression level and memory usage, standard memory allocation
1247 functions). The source code of these utility functions can be modified if
1248 you need special options.
1249 */
1250
1251 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1252 const Bytef *source, uLong sourceLen));
1253 /*
1254 Compresses the source buffer into the destination buffer. sourceLen is
1255 the byte length of the source buffer. Upon entry, destLen is the total size
1256 of the destination buffer, which must be at least the value returned by
1257 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1258 compressed data. compress() is equivalent to compress2() with a level
1259 parameter of Z_DEFAULT_COMPRESSION.
1260
1261 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1262 enough memory, Z_BUF_ERROR if there was not enough room in the output
1263 buffer.
1264 */
1265
1266 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1267 const Bytef *source, uLong sourceLen,
1268 int level));
1269 /*
1270 Compresses the source buffer into the destination buffer. The level
1271 parameter has the same meaning as in deflateInit. sourceLen is the byte
1272 length of the source buffer. Upon entry, destLen is the total size of the
1273 destination buffer, which must be at least the value returned by
1274 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1275 compressed data.
1276
1277 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1278 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1279 Z_STREAM_ERROR if the level parameter is invalid.
1280 */
1281
1282 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1283 /*
1284 compressBound() returns an upper bound on the compressed size after
1285 compress() or compress2() on sourceLen bytes. It would be used before a
1286 compress() or compress2() call to allocate the destination buffer.
1287 */
1288
1289 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1290 const Bytef *source, uLong sourceLen));
1291 /*
1292 Decompresses the source buffer into the destination buffer. sourceLen is
1293 the byte length of the source buffer. Upon entry, destLen is the total size
1294 of the destination buffer, which must be large enough to hold the entire
1295 uncompressed data. (The size of the uncompressed data must have been saved
1296 previously by the compressor and transmitted to the decompressor by some
1297 mechanism outside the scope of this compression library.) Upon exit, destLen
1298 is the actual size of the uncompressed data.
1299
1300 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1301 enough memory, Z_BUF_ERROR if there was not enough room in the output
1302 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1303 the case where there is not enough room, uncompress() will fill the output
1304 buffer with the uncompressed data up to that point.
1305 */
1306
1307 ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen,
1308 const Bytef *source, uLong *sourceLen));
1309 /*
1310 Same as uncompress, except that sourceLen is a pointer, where the
1311 length of the source is *sourceLen. On return, *sourceLen is the number of
1312 source bytes consumed.
1313 */
1314
1315 /* gzip file access functions */
1316
1317 /*
1318 This library supports reading and writing files in gzip (.gz) format with
1319 an interface similar to that of stdio, using the functions that start with
1320 "gz". The gzip format is different from the zlib format. gzip is a gzip
1321 wrapper, documented in RFC 1952, wrapped around a deflate stream.
1322 */
1323
1324 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1325
1326 /*
1327 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1328
1329 Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1330 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1331 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1332 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1333 for fixed code compression as in "wb9F". (See the description of
1334 deflateInit2 for more information about the strategy parameter.) 'T' will
1335 request transparent writing or appending with no compression and not using
1336 the gzip format.
1337
1338 "a" can be used instead of "w" to request that the gzip stream that will
1339 be written be appended to the file. "+" will result in an error, since
1340 reading and writing to the same gzip file is not supported. The addition of
1341 "x" when writing will create the file exclusively, which fails if the file
1342 already exists. On systems that support it, the addition of "e" when
1343 reading or writing will set the flag to close the file on an execve() call.
1344
1345 These functions, as well as gzip, will read and decode a sequence of gzip
1346 streams in a file. The append function of gzopen() can be used to create
1347 such a file. (Also see gzflush() for another way to do this.) When
1348 appending, gzopen does not test whether the file begins with a gzip stream,
1349 nor does it look for the end of the gzip streams to begin appending. gzopen
1350 will simply append a gzip stream to the existing file.
1351
1352 gzopen can be used to read a file which is not in gzip format; in this
1353 case gzread will directly read from the file without decompression. When
1354 reading, this will be detected automatically by looking for the magic two-
1355 byte gzip header.
1356
1357 gzopen returns NULL if the file could not be opened, if there was
1358 insufficient memory to allocate the gzFile state, or if an invalid mode was
1359 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1360 errno can be checked to determine if the reason gzopen failed was that the
1361 file could not be opened.
1362 */
1363
1364 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1365 /*
1366 gzdopen associates a gzFile with the file descriptor fd. File descriptors
1367 are obtained from calls like open, dup, creat, pipe or fileno (if the file
1368 has been previously opened with fopen). The mode parameter is as in gzopen.
1369
1370 The next call of gzclose on the returned gzFile will also close the file
1371 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1372 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1373 mode);. The duplicated descriptor should be saved to avoid a leak, since
1374 gzdopen does not close fd if it fails. If you are using fileno() to get the
1375 file descriptor from a FILE *, then you will have to use dup() to avoid
1376 double-close()ing the file descriptor. Both gzclose() and fclose() will
1377 close the associated file descriptor, so they need to have different file
1378 descriptors.
1379
1380 gzdopen returns NULL if there was insufficient memory to allocate the
1381 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1382 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1383 used until the next gz* read, write, seek, or close operation, so gzdopen
1384 will not detect if fd is invalid (unless fd is -1).
1385 */
1386
1387 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1388 /*
1389 Set the internal buffer size used by this library's functions. The
1390 default buffer size is 8192 bytes. This function must be called after
1391 gzopen() or gzdopen(), and before any other calls that read or write the
1392 file. The buffer memory allocation is always deferred to the first read or
1393 write. Three times that size in buffer space is allocated. A larger buffer
1394 size of, for example, 64K or 128K bytes will noticeably increase the speed
1395 of decompression (reading).
1396
1397 The new buffer size also affects the maximum length for gzprintf().
1398
1399 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1400 too late.
1401 */
1402
1403 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1404 /*
1405 Dynamically update the compression level or strategy. See the description
1406 of deflateInit2 for the meaning of these parameters. Previously provided
1407 data is flushed before the parameter change.
1408
1409 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
1410 opened for writing, Z_ERRNO if there is an error writing the flushed data,
1411 or Z_MEM_ERROR if there is a memory allocation error.
1412 */
1413
1414 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1415 /*
1416 Reads the given number of uncompressed bytes from the compressed file. If
1417 the input file is not in gzip format, gzread copies the given number of
1418 bytes into the buffer directly from the file.
1419
1420 After reaching the end of a gzip stream in the input, gzread will continue
1421 to read, looking for another gzip stream. Any number of gzip streams may be
1422 concatenated in the input file, and will all be decompressed by gzread().
1423 If something other than a gzip stream is encountered after a gzip stream,
1424 that remaining trailing garbage is ignored (and no error is returned).
1425
1426 gzread can be used to read a gzip file that is being concurrently written.
1427 Upon reaching the end of the input, gzread will return with the available
1428 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1429 gzclearerr can be used to clear the end of file indicator in order to permit
1430 gzread to be tried again. Z_OK indicates that a gzip stream was completed
1431 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1432 middle of a gzip stream. Note that gzread does not return -1 in the event
1433 of an incomplete gzip stream. This error is deferred until gzclose(), which
1434 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1435 stream. Alternatively, gzerror can be used before gzclose to detect this
1436 case.
1437
1438 gzread returns the number of uncompressed bytes actually read, less than
1439 len for end of file, or -1 for error. If len is too large to fit in an int,
1440 then nothing is read, -1 is returned, and the error state is set to
1441 Z_STREAM_ERROR.
1442 */
1443
1444 ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems,
1445 gzFile file));
1446 /*
1447 Read up to nitems items of size size from file to buf, otherwise operating
1448 as gzread() does. This duplicates the interface of stdio's fread(), with
1449 size_t request and return types. If the library defines size_t, then
1450 z_size_t is identical to size_t. If not, then z_size_t is an unsigned
1451 integer type that can contain a pointer.
1452
1453 gzfread() returns the number of full items read of size size, or zero if
1454 the end of the file was reached and a full item could not be read, or if
1455 there was an error. gzerror() must be consulted if zero is returned in
1456 order to determine if there was an error. If the multiplication of size and
1457 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing
1458 is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
1459
1460 In the event that the end of file is reached and only a partial item is
1461 available at the end, i.e. the remaining uncompressed data length is not a
1462 multiple of size, then the final partial item is nevetheless read into buf
1463 and the end-of-file flag is set. The length of the partial item read is not
1464 provided, but could be inferred from the result of gztell(). This behavior
1465 is the same as the behavior of fread() implementations in common libraries,
1466 but it prevents the direct use of gzfread() to read a concurrently written
1467 file, reseting and retrying on end-of-file, when size is not 1.
1468 */
1469
1470 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1471 voidpc buf, unsigned len));
1472 /*
1473 Writes the given number of uncompressed bytes into the compressed file.
1474 gzwrite returns the number of uncompressed bytes written or 0 in case of
1475 error.
1476 */
1477
1478 ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
1479 z_size_t nitems, gzFile file));
1480 /*
1481 gzfwrite() writes nitems items of size size from buf to file, duplicating
1482 the interface of stdio's fwrite(), with size_t request and return types. If
1483 the library defines size_t, then z_size_t is identical to size_t. If not,
1484 then z_size_t is an unsigned integer type that can contain a pointer.
1485
1486 gzfwrite() returns the number of full items written of size size, or zero
1487 if there was an error. If the multiplication of size and nitems overflows,
1488 i.e. the product does not fit in a z_size_t, then nothing is written, zero
1489 is returned, and the error state is set to Z_STREAM_ERROR.
1490 */
1491
1492 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1493 /*
1494 Converts, formats, and writes the arguments to the compressed file under
1495 control of the format string, as in fprintf. gzprintf returns the number of
1496 uncompressed bytes actually written, or a negative zlib error code in case
1497 of error. The number of uncompressed bytes written is limited to 8191, or
1498 one less than the buffer size given to gzbuffer(). The caller should assure
1499 that this limit is not exceeded. If it is exceeded, then gzprintf() will
1500 return an error (0) with nothing written. In this case, there may also be a
1501 buffer overflow with unpredictable consequences, which is possible only if
1502 zlib was compiled with the insecure functions sprintf() or vsprintf()
1503 because the secure snprintf() or vsnprintf() functions were not available.
1504 This can be determined using zlibCompileFlags().
1505 */
1506
1507 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1508 /*
1509 Writes the given null-terminated string to the compressed file, excluding
1510 the terminating null character.
1511
1512 gzputs returns the number of characters written, or -1 in case of error.
1513 */
1514
1515 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1516 /*
1517 Reads bytes from the compressed file until len-1 characters are read, or a
1518 newline character is read and transferred to buf, or an end-of-file
1519 condition is encountered. If any characters are read or if len == 1, the
1520 string is terminated with a null character. If no characters are read due
1521 to an end-of-file or len < 1, then the buffer is left untouched.
1522
1523 gzgets returns buf which is a null-terminated string, or it returns NULL
1524 for end-of-file or in case of error. If there was an error, the contents at
1525 buf are indeterminate.
1526 */
1527
1528 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1529 /*
1530 Writes c, converted to an unsigned char, into the compressed file. gzputc
1531 returns the value that was written, or -1 in case of error.
1532 */
1533
1534 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1535 /*
1536 Reads one byte from the compressed file. gzgetc returns this byte or -1
1537 in case of end of file or error. This is implemented as a macro for speed.
1538 As such, it does not do all of the checking the other functions do. I.e.
1539 it does not check to see if file is NULL, nor whether the structure file
1540 points to has been clobbered or not.
1541 */
1542
1543 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1544 /*
1545 Push one character back onto the stream to be read as the first character
1546 on the next read. At least one character of push-back is allowed.
1547 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1548 fail if c is -1, and may fail if a character has been pushed but not read
1549 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1550 output buffer size of pushed characters is allowed. (See gzbuffer above.)
1551 The pushed character will be discarded if the stream is repositioned with
1552 gzseek() or gzrewind().
1553 */
1554
1555 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1556 /*
1557 Flushes all pending output into the compressed file. The parameter flush
1558 is as in the deflate() function. The return value is the zlib error number
1559 (see function gzerror below). gzflush is only permitted when writing.
1560
1561 If the flush parameter is Z_FINISH, the remaining data is written and the
1562 gzip stream is completed in the output. If gzwrite() is called again, a new
1563 gzip stream will be started in the output. gzread() is able to read such
1564 concatenated gzip streams.
1565
1566 gzflush should be called only when strictly necessary because it will
1567 degrade compression if called too often.
1568 */
1569
1570 /*
1571 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1572 z_off_t offset, int whence));
1573
1574 Sets the starting position for the next gzread or gzwrite on the given
1575 compressed file. The offset represents a number of bytes in the
1576 uncompressed data stream. The whence parameter is defined as in lseek(2);
1577 the value SEEK_END is not supported.
1578
1579 If the file is opened for reading, this function is emulated but can be
1580 extremely slow. If the file is opened for writing, only forward seeks are
1581 supported; gzseek then compresses a sequence of zeroes up to the new
1582 starting position.
1583
1584 gzseek returns the resulting offset location as measured in bytes from
1585 the beginning of the uncompressed stream, or -1 in case of error, in
1586 particular if the file is opened for writing and the new starting position
1587 would be before the current position.
1588 */
1589
1590 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1591 /*
1592 Rewinds the given file. This function is supported only for reading.
1593
1594 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1595 */
1596
1597 /*
1598 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1599
1600 Returns the starting position for the next gzread or gzwrite on the given
1601 compressed file. This position represents a number of bytes in the
1602 uncompressed data stream, and is zero when starting, even if appending or
1603 reading a gzip stream from the middle of a file using gzdopen().
1604
1605 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1606 */
1607
1608 /*
1609 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1610
1611 Returns the current offset in the file being read or written. This offset
1612 includes the count of bytes that precede the gzip stream, for example when
1613 appending or when using gzdopen() for reading. When reading, the offset
1614 does not include as yet unused buffered input. This information can be used
1615 for a progress indicator. On error, gzoffset() returns -1.
1616 */
1617
1618 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1619 /*
1620 Returns true (1) if the end-of-file indicator has been set while reading,
1621 false (0) otherwise. Note that the end-of-file indicator is set only if the
1622 read tried to go past the end of the input, but came up short. Therefore,
1623 just like feof(), gzeof() may return false even if there is no more data to
1624 read, in the event that the last read request was for the exact number of
1625 bytes remaining in the input file. This will happen if the input file size
1626 is an exact multiple of the buffer size.
1627
1628 If gzeof() returns true, then the read functions will return no more data,
1629 unless the end-of-file indicator is reset by gzclearerr() and the input file
1630 has grown since the previous end of file was detected.
1631 */
1632
1633 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1634 /*
1635 Returns true (1) if file is being copied directly while reading, or false
1636 (0) if file is a gzip stream being decompressed.
1637
1638 If the input file is empty, gzdirect() will return true, since the input
1639 does not contain a gzip stream.
1640
1641 If gzdirect() is used immediately after gzopen() or gzdopen() it will
1642 cause buffers to be allocated to allow reading the file to determine if it
1643 is a gzip file. Therefore if gzbuffer() is used, it should be called before
1644 gzdirect().
1645
1646 When writing, gzdirect() returns true (1) if transparent writing was
1647 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1648 gzdirect() is not needed when writing. Transparent writing must be
1649 explicitly requested, so the application already knows the answer. When
1650 linking statically, using gzdirect() will include all of the zlib code for
1651 gzip file reading and decompression, which may not be desired.)
1652 */
1653
1654 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1655 /*
1656 Flushes all pending output if necessary, closes the compressed file and
1657 deallocates the (de)compression state. Note that once file is closed, you
1658 cannot call gzerror with file, since its structures have been deallocated.
1659 gzclose must not be called more than once on the same file, just as free
1660 must not be called more than once on the same allocation.
1661
1662 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1663 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1664 last read ended in the middle of a gzip stream, or Z_OK on success.
1665 */
1666
1667 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1668 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1669 /*
1670 Same as gzclose(), but gzclose_r() is only for use when reading, and
1671 gzclose_w() is only for use when writing or appending. The advantage to
1672 using these instead of gzclose() is that they avoid linking in zlib
1673 compression or decompression code that is not used when only reading or only
1674 writing respectively. If gzclose() is used, then both compression and
1675 decompression code will be included the application when linking to a static
1676 zlib library.
1677 */
1678
1679 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1680 /*
1681 Returns the error message for the last error which occurred on the given
1682 compressed file. errnum is set to zlib error number. If an error occurred
1683 in the file system and not in the compression library, errnum is set to
1684 Z_ERRNO and the application may consult errno to get the exact error code.
1685
1686 The application must not modify the returned string. Future calls to
1687 this function may invalidate the previously returned string. If file is
1688 closed, then the string previously returned by gzerror will no longer be
1689 available.
1690
1691 gzerror() should be used to distinguish errors from end-of-file for those
1692 functions above that do not distinguish those cases in their return values.
1693 */
1694
1695 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1696 /*
1697 Clears the error and end-of-file flags for file. This is analogous to the
1698 clearerr() function in stdio. This is useful for continuing to read a gzip
1699 file that is being written concurrently.
1700 */
1701
1702 #endif /* !Z_SOLO */
1703
1704 /* checksum functions */
1705
1706 /*
1707 These functions are not related to compression but are exported
1708 anyway because they might be useful in applications using the compression
1709 library.
1710 */
1711
1712 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1713 /*
1714 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1715 return the updated checksum. If buf is Z_NULL, this function returns the
1716 required initial value for the checksum.
1717
1718 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1719 much faster.
1720
1721 Usage example:
1722
1723 uLong adler = adler32(0L, Z_NULL, 0);
1724
1725 while (read_buffer(buffer, length) != EOF) {
1726 adler = adler32(adler, buffer, length);
1727 }
1728 if (adler != original_adler) error();
1729 */
1730
1731 ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf,
1732 z_size_t len));
1733 /*
1734 Same as adler32(), but with a size_t length.
1735 */
1736
1737 /*
1738 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1739 z_off_t len2));
1740
1741 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1742 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1743 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1744 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1745 that the z_off_t type (like off_t) is a signed integer. If len2 is
1746 negative, the result has no meaning or utility.
1747 */
1748
1749 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1750 /*
1751 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1752 updated CRC-32. If buf is Z_NULL, this function returns the required
1753 initial value for the crc. Pre- and post-conditioning (one's complement) is
1754 performed within this function so it shouldn't be done by the application.
1755
1756 Usage example:
1757
1758 uLong crc = crc32(0L, Z_NULL, 0);
1759
1760 while (read_buffer(buffer, length) != EOF) {
1761 crc = crc32(crc, buffer, length);
1762 }
1763 if (crc != original_crc) error();
1764 */
1765
1766 ZEXTERN uLong ZEXPORT crc32_z OF((uLong adler, const Bytef *buf,
1767 z_size_t len));
1768 /*
1769 Same as crc32(), but with a size_t length.
1770 */
1771
1772 /*
1773 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1774
1775 Combine two CRC-32 check values into one. For two sequences of bytes,
1776 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1777 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1778 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1779 len2.
1780 */
1781
1782
1783 /* various hacks, don't look :) */
1784
1785 /* deflateInit and inflateInit are macros to allow checking the zlib version
1786 * and the compiler's view of z_stream:
1787 */
1788 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1789 const char *version, int stream_size));
1790 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1791 const char *version, int stream_size));
1792 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1793 int windowBits, int memLevel,
1794 int strategy, const char *version,
1795 int stream_size));
1796 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1797 const char *version, int stream_size));
1798 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1799 unsigned char FAR *window,
1800 const char *version,
1801 int stream_size));
1802 #ifdef Z_PREFIX_SET
1803 # define z_deflateInit(strm, level) \
1804 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1805 # define z_inflateInit(strm) \
1806 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1807 # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1808 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1809 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1810 # define z_inflateInit2(strm, windowBits) \
1811 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1812 (int)sizeof(z_stream))
1813 # define z_inflateBackInit(strm, windowBits, window) \
1814 inflateBackInit_((strm), (windowBits), (window), \
1815 ZLIB_VERSION, (int)sizeof(z_stream))
1816 #else
1817 # define deflateInit(strm, level) \
1818 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1819 # define inflateInit(strm) \
1820 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1821 # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1822 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1823 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1824 # define inflateInit2(strm, windowBits) \
1825 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1826 (int)sizeof(z_stream))
1827 # define inflateBackInit(strm, windowBits, window) \
1828 inflateBackInit_((strm), (windowBits), (window), \
1829 ZLIB_VERSION, (int)sizeof(z_stream))
1830 #endif
1831
1832 #ifndef Z_SOLO
1833
1834 /* gzgetc() macro and its supporting function and exposed data structure. Note
1835 * that the real internal state is much larger than the exposed structure.
1836 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1837 * user should not mess with these exposed elements, since their names or
1838 * behavior could change in the future, perhaps even capriciously. They can
1839 * only be used by the gzgetc() macro. You have been warned.
1840 */
1841 struct gzFile_s {
1842 unsigned have;
1843 unsigned char *next;
1844 z_off64_t pos;
1845 };
1846 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
1847 #ifdef Z_PREFIX_SET
1848 # undef z_gzgetc
1849 # define z_gzgetc(g) \
1850 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1851 #else
1852 # define gzgetc(g) \
1853 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1854 #endif
1855
1856 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1857 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1858 * both are true, the application gets the *64 functions, and the regular
1859 * functions are changed to 64 bits) -- in case these are set on systems
1860 * without large file support, _LFS64_LARGEFILE must also be true
1861 */
1862 #ifdef Z_LARGE64
1863 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1864 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1865 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1866 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1867 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1868 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1869 #endif
1870
1871 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1872 # ifdef Z_PREFIX_SET
1873 # define z_gzopen z_gzopen64
1874 # define z_gzseek z_gzseek64
1875 # define z_gztell z_gztell64
1876 # define z_gzoffset z_gzoffset64
1877 # define z_adler32_combine z_adler32_combine64
1878 # define z_crc32_combine z_crc32_combine64
1879 # else
1880 # define gzopen gzopen64
1881 # define gzseek gzseek64
1882 # define gztell gztell64
1883 # define gzoffset gzoffset64
1884 # define adler32_combine adler32_combine64
1885 # define crc32_combine crc32_combine64
1886 # endif
1887 # ifndef Z_LARGE64
1888 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1889 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1890 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1891 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1892 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1893 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1894 # endif
1895 #else
1896 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1897 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1898 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1899 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1900 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1901 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1902 #endif
1903
1904 #else /* Z_SOLO */
1905
1906 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1907 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1908
1909 #endif /* !Z_SOLO */
1910
1911 /* undocumented functions */
1912 ZEXTERN const char * ZEXPORT zError OF((int));
1913 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1914 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1915 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1916 ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int));
1917 ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF ((z_streamp));
1918 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1919 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1920 #if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
1921 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1922 const char *mode));
1923 #endif
1924 #if defined(STDC) || defined(Z_HAVE_STDARG_H)
1925 # ifndef Z_SOLO
1926 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1927 const char *format,
1928 va_list va));
1929 # endif
1930 #endif
1931
1932 #ifdef __cplusplus
1933 }
1934 #endif
1935
1936 #endif /* ZLIB_H */