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 1.2.8, April 28th, 2013
27
28 Copyright (C) 1995-2013 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 "1.2.8"
65 #define ZLIB_VERNUM 0x1280
66 #define ZLIB_VER_MAJOR 1
67 #define ZLIB_VER_MINOR 2
68 #define ZLIB_VER_REVISION 8
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 streams in memory as well.
93
94 The zlib format was designed to be compact and fast for use in memory
95 and on communications channels. The gzip format was designed for single-
96 file compression on file systems, has a larger header than zlib to maintain
97 directory information, and uses a different, slower check method than zlib.
98
99 The library does not install any signal handler. The decoder checks
100 the consistency of the compressed data, so the library should never crash
101 even in case of corrupted input.
102 */
103
104 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
105 typedef void (*free_func) OF((voidpf opaque, voidpf address));
106
107 struct internal_state;
108
109 typedef struct z_stream_s {
110 z_const Bytef *next_in; /* next input byte */
111 uInt avail_in; /* number of bytes available at next_in */
112 uLong total_in; /* total number of input bytes read so far */
113
114 Bytef *next_out; /* next output byte should be put there */
115 uInt avail_out; /* remaining free space at next_out */
116 uLong total_out; /* total number of bytes output so far */
117
118 z_const char *msg; /* last error message, NULL if no error */
119 struct internal_state FAR *state; /* not visible by applications */
120
121 alloc_func zalloc; /* used to allocate the internal state */
122 free_func zfree; /* used to free the internal state */
123 voidpf opaque; /* private data object passed to zalloc and zfree */
124
125 int data_type; /* best guess about the data type: binary or text */
126 uLong adler; /* adler32 value of the uncompressed data */
127 uLong reserved; /* reserved for future use */
128 } z_stream;
129
130 typedef z_stream FAR *z_streamp;
131
132 /*
133 gzip header information passed to and from zlib routines. See RFC 1952
134 for more details on the meanings of these fields.
135 */
136 typedef struct gz_header_s {
137 int text; /* true if compressed data believed to be text */
138 uLong time; /* modification time */
139 int xflags; /* extra flags (not used when writing a gzip file) */
140 int os; /* operating system */
141 Bytef *extra; /* pointer to extra field or Z_NULL if none */
142 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
143 uInt extra_max; /* space at extra (only when reading header) */
144 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
145 uInt name_max; /* space at name (only when reading header) */
146 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
147 uInt comm_max; /* space at comment (only when reading header) */
148 int hcrc; /* true if there was or will be a header crc */
149 int done; /* true when done reading gzip header (not used
150 when writing a gzip file) */
151 } gz_header;
152
153 typedef gz_header FAR *gz_headerp;
154
155 /*
156 The application must update next_in and avail_in when avail_in has dropped
157 to zero. It must update next_out and avail_out when avail_out has dropped
158 to zero. The application must initialize zalloc, zfree and opaque before
159 calling the init function. All other fields are set by the compression
160 library and must not be updated by the application.
161
162 The opaque value provided by the application will be passed as the first
163 parameter for calls of zalloc and zfree. This can be useful for custom
164 memory management. The compression library attaches no meaning to the
165 opaque value.
166
167 zalloc must return Z_NULL if there is not enough memory for the object.
168 If zlib is used in a multi-threaded application, zalloc and zfree must be
169 thread safe.
170
171 On 16-bit systems, the functions zalloc and zfree must be able to allocate
172 exactly 65536 bytes, but will not be required to allocate more than this if
173 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
174 returned by zalloc for objects of exactly 65536 bytes *must* have their
175 offset normalized to zero. The default allocation function provided by this
176 library ensures this (see zutil.c). To reduce memory requirements and avoid
177 any allocation of 64K objects, at the expense of compression ratio, compile
178 the library with -DMAX_WBITS=14 (see zconf.h).
179
180 The fields total_in and total_out can be used for statistics or progress
181 reports. After compression, total_in holds the total size of the
182 uncompressed data and may be saved for use in the decompressor (particularly
183 if the decompressor wants to decompress everything in a single step).
184 */
185
186 /* constants */
187
188 #define Z_NO_FLUSH 0
189 #define Z_PARTIAL_FLUSH 1
190 #define Z_SYNC_FLUSH 2
191 #define Z_FULL_FLUSH 3
192 #define Z_FINISH 4
193 #define Z_BLOCK 5
194 #define Z_TREES 6
195 /* Allowed flush values; see deflate() and inflate() below for details */
196
197 #define Z_OK 0
198 #define Z_STREAM_END 1
199 #define Z_NEED_DICT 2
200 #define Z_ERRNO (-1)
201 #define Z_STREAM_ERROR (-2)
202 #define Z_DATA_ERROR (-3)
203 #define Z_MEM_ERROR (-4)
204 #define Z_BUF_ERROR (-5)
205 #define Z_VERSION_ERROR (-6)
206 /* Return codes for the compression/decompression functions. Negative values
207 * are errors, positive values are used for special but normal events.
208 */
209
210 #define Z_NO_COMPRESSION 0
211 #define Z_BEST_SPEED 1
212 #define Z_BEST_COMPRESSION 9
213 #define Z_DEFAULT_COMPRESSION (-1)
214 /* compression levels */
215
216 #define Z_FILTERED 1
217 #define Z_HUFFMAN_ONLY 2
218 #define Z_RLE 3
219 #define Z_FIXED 4
220 #define Z_DEFAULT_STRATEGY 0
221 /* compression strategy; see deflateInit2() below for details */
222
223 #define Z_BINARY 0
224 #define Z_TEXT 1
225 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
226 #define Z_UNKNOWN 2
227 /* Possible values of the data_type field (though see inflate()) */
228
229 #define Z_DEFLATED 8
230 /* The deflate compression method (the only one supported in this version) */
231
232 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
233
234 #define zlib_version zlibVersion()
235 /* for compatibility with versions < 1.0.2 */
236
237
238 /* basic functions */
239
240 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
241 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
242 If the first character differs, the library code actually used is not
243 compatible with the zlib.h header file used by the application. This check
244 is automatically made by deflateInit and inflateInit.
245 */
246
247 /*
248 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
249
250 Initializes the internal stream state for compression. The fields
251 zalloc, zfree and opaque must be initialized before by the caller. If
252 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
253 allocation functions.
254
255 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
256 1 gives best speed, 9 gives best compression, 0 gives no compression at all
257 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
258 requests a default compromise between speed and compression (currently
259 equivalent to level 6).
260
261 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
262 memory, Z_STREAM_ERROR if level is not a valid compression level, or
263 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
264 with the version assumed by the caller (ZLIB_VERSION). msg is set to null
265 if there is no error message. deflateInit does not perform any compression:
266 this will be done by deflate().
267 */
268
269
270 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
271 /*
272 deflate compresses as much data as possible, and stops when the input
273 buffer becomes empty or the output buffer becomes full. It may introduce
274 some output latency (reading input without producing any output) except when
275 forced to flush.
276
277 The detailed semantics are as follows. deflate performs one or both of the
278 following actions:
279
280 - Compress more input starting at next_in and update next_in and avail_in
281 accordingly. If not all input can be processed (because there is not
282 enough room in the output buffer), next_in and avail_in are updated and
283 processing will resume at this point for the next call of deflate().
284
285 - Provide more output starting at next_out and update next_out and avail_out
286 accordingly. This action is forced if the parameter flush is non zero.
287 Forcing flush frequently degrades the compression ratio, so this parameter
288 should be set only when necessary (in interactive applications). Some
289 output may be provided even if flush is not set.
290
291 Before the call of deflate(), the application should ensure that at least
292 one of the actions is possible, by providing more input and/or consuming more
293 output, and updating avail_in or avail_out accordingly; avail_out should
294 never be zero before the call. The application can consume the compressed
295 output when it wants, for example when the output buffer is full (avail_out
296 == 0), or after each call of deflate(). If deflate returns Z_OK and with
297 zero avail_out, it must be called again after making room in the output
298 buffer because there might be more output pending.
299
300 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
301 decide how much data to accumulate before producing output, in order to
302 maximize compression.
303
304 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
305 flushed to the output buffer and the output is aligned on a byte boundary, so
306 that the decompressor can get all input data available so far. (In
307 particular avail_in is zero after the call if enough output space has been
308 provided before the call.) Flushing may degrade compression for some
309 compression algorithms and so it should be used only when necessary. This
310 completes the current deflate block and follows it with an empty stored block
311 that is three bits plus filler bits to the next byte, followed by four bytes
312 (00 00 ff ff).
313
314 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
315 output buffer, but the output is not aligned to a byte boundary. All of the
316 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
317 This completes the current deflate block and follows it with an empty fixed
318 codes block that is 10 bits long. This assures that enough bytes are output
319 in order for the decompressor to finish the block before the empty fixed code
320 block.
321
322 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
323 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
324 seven bits of the current block are held to be written as the next byte after
325 the next deflate block is completed. In this case, the decompressor may not
326 be provided enough bits at this point in order to complete decompression of
327 the data provided so far to the compressor. It may need to wait for the next
328 block to be emitted. This is for advanced applications that need to control
329 the emission of deflate blocks.
330
331 If flush is set to Z_FULL_FLUSH, all output is flushed as with
332 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
333 restart from this point if previous compressed data has been damaged or if
334 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
335 compression.
336
337 If deflate returns with avail_out == 0, this function must be called again
338 with the same value of the flush parameter and more output space (updated
339 avail_out), until the flush is complete (deflate returns with non-zero
340 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
341 avail_out is greater than six to avoid repeated flush markers due to
342 avail_out == 0 on return.
343
344 If the parameter flush is set to Z_FINISH, pending input is processed,
345 pending output is flushed and deflate returns with Z_STREAM_END if there was
346 enough output space; if deflate returns with Z_OK, this function must be
347 called again with Z_FINISH and more output space (updated avail_out) but no
348 more input data, until it returns with Z_STREAM_END or an error. After
349 deflate has returned Z_STREAM_END, the only possible operations on the stream
350 are deflateReset or deflateEnd.
351
352 Z_FINISH can be used immediately after deflateInit if all the compression
353 is to be done in a single step. In this case, avail_out must be at least the
354 value returned by deflateBound (see below). Then deflate is guaranteed to
355 return Z_STREAM_END. If not enough output space is provided, deflate will
356 not return Z_STREAM_END, and it must be called again as described above.
357
358 deflate() sets strm->adler to the adler32 checksum of all input read
359 so far (that is, total_in bytes).
360
361 deflate() may update strm->data_type if it can make a good guess about
362 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
363 binary. This field is only for information purposes and does not affect the
364 compression algorithm in any manner.
365
366 deflate() returns Z_OK if some progress has been made (more input
367 processed or more output produced), Z_STREAM_END if all input has been
368 consumed and all output has been produced (only when flush is set to
369 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
370 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
371 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
372 fatal, and deflate() can be called again with more input and more output
373 space to continue compressing.
374 */
375
376
377 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
378 /*
379 All dynamically allocated data structures for this stream are freed.
380 This function discards any unprocessed input and does not flush any pending
381 output.
382
383 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
384 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
385 prematurely (some input or output was discarded). In the error case, msg
386 may be set but then points to a static string (which must not be
387 deallocated).
388 */
389
390
391 /*
392 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
393
394 Initializes the internal stream state for decompression. The fields
395 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
396 the caller. If next_in is not Z_NULL and avail_in is large enough (the
397 exact value depends on the compression method), inflateInit determines the
398 compression method from the zlib header and allocates all data structures
399 accordingly; otherwise the allocation will be deferred to the first call of
400 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
401 use default allocation functions.
402
403 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
404 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
405 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
406 invalid, such as a null pointer to the structure. msg is set to null if
407 there is no error message. inflateInit does not perform any decompression
408 apart from possibly reading the zlib header if present: actual decompression
409 will be done by inflate(). (So next_in and avail_in may be modified, but
410 next_out and avail_out are unused and unchanged.) The current implementation
411 of inflateInit() does not process any header information -- that is deferred
412 until inflate() is called.
413 */
414
415
416 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
417 /*
418 inflate decompresses as much data as possible, and stops when the input
419 buffer becomes empty or the output buffer becomes full. It may introduce
420 some output latency (reading input without producing any output) except when
421 forced to flush.
422
423 The detailed semantics are as follows. inflate performs one or both of the
424 following actions:
425
426 - Decompress more input starting at next_in and update next_in and avail_in
427 accordingly. If not all input can be processed (because there is not
428 enough room in the output buffer), next_in is updated and processing will
429 resume at this point for the next call of inflate().
430
431 - Provide more output starting at next_out and update next_out and avail_out
432 accordingly. inflate() provides as much output as possible, until there is
433 no more input data or no more space in the output buffer (see below about
434 the flush parameter).
435
436 Before the call of inflate(), the application should ensure that at least
437 one of the actions is possible, by providing more input and/or consuming more
438 output, and updating the next_* and avail_* values accordingly. The
439 application can consume the uncompressed output when it wants, for example
440 when the output buffer is full (avail_out == 0), or after each call of
441 inflate(). If inflate returns Z_OK and with zero avail_out, it must be
442 called again after making room in the output buffer because there might be
443 more output pending.
444
445 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
446 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
447 output as possible to the output buffer. Z_BLOCK requests that inflate()
448 stop if and when it gets to the next deflate block boundary. When decoding
449 the zlib or gzip format, this will cause inflate() to return immediately
450 after the header and before the first block. When doing a raw inflate,
451 inflate() will go ahead and process the first block, and will return when it
452 gets to the end of that block, or when it runs out of data.
453
454 The Z_BLOCK option assists in appending to or combining deflate streams.
455 Also to assist in this, on return inflate() will set strm->data_type to the
456 number of unused bits in the last byte taken from strm->next_in, plus 64 if
457 inflate() is currently decoding the last block in the deflate stream, plus
458 128 if inflate() returned immediately after decoding an end-of-block code or
459 decoding the complete header up to just before the first byte of the deflate
460 stream. The end-of-block will not be indicated until all of the uncompressed
461 data from that block has been written to strm->next_out. The number of
462 unused bits may in general be greater than seven, except when bit 7 of
463 data_type is set, in which case the number of unused bits will be less than
464 eight. data_type is set as noted here every time inflate() returns for all
465 flush options, and so can be used to determine the amount of currently
466 consumed input in bits.
467
468 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
469 end of each deflate block header is reached, before any actual data in that
470 block is decoded. This allows the caller to determine the length of the
471 deflate block header for later use in random access within a deflate block.
472 256 is added to the value of strm->data_type when inflate() returns
473 immediately after reaching the end of the deflate block header.
474
475 inflate() should normally be called until it returns Z_STREAM_END or an
476 error. However if all decompression is to be performed in a single step (a
477 single call of inflate), the parameter flush should be set to Z_FINISH. In
478 this case all pending input is processed and all pending output is flushed;
479 avail_out must be large enough to hold all of the uncompressed data for the
480 operation to complete. (The size of the uncompressed data may have been
481 saved by the compressor for this purpose.) The use of Z_FINISH is not
482 required to perform an inflation in one step. However it may be used to
483 inform inflate that a faster approach can be used for the single inflate()
484 call. Z_FINISH also informs inflate to not maintain a sliding window if the
485 stream completes, which reduces inflate's memory footprint. If the stream
486 does not complete, either because not all of the stream is provided or not
487 enough output space is provided, then a sliding window will be allocated and
488 inflate() can be called again to continue the operation as if Z_NO_FLUSH had
489 been used.
490
491 In this implementation, inflate() always flushes as much output as
492 possible to the output buffer, and always uses the faster approach on the
493 first call. So the effects of the flush parameter in this implementation are
494 on the return value of inflate() as noted below, when inflate() returns early
495 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
496 memory for a sliding window when Z_FINISH is used.
497
498 If a preset dictionary is needed after this call (see inflateSetDictionary
499 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
500 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
501 strm->adler to the Adler-32 checksum of all output produced so far (that is,
502 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
503 below. At the end of the stream, inflate() checks that its computed adler32
504 checksum is equal to that saved by the compressor and returns Z_STREAM_END
505 only if the checksum is correct.
506
507 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
508 deflate data. The header type is detected automatically, if requested when
509 initializing with inflateInit2(). Any information contained in the gzip
510 header is not retained, so applications that need that information should
511 instead use raw inflate, see inflateInit2() below, or inflateBack() and
512 perform their own processing of the gzip header and trailer. When processing
513 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
514 producted so far. The CRC-32 is checked against the gzip trailer.
515
516 inflate() returns Z_OK if some progress has been made (more input processed
517 or more output produced), Z_STREAM_END if the end of the compressed data has
518 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
519 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
520 corrupted (input stream not conforming to the zlib format or incorrect check
521 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
522 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
523 Z_BUF_ERROR if no progress is possible or if there was not enough room in the
524 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
525 inflate() can be called again with more input and more output space to
526 continue decompressing. If Z_DATA_ERROR is returned, the application may
527 then call inflateSync() to look for a good compression block if a partial
528 recovery of the data is desired.
529 */
530
531
532 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
533 /*
534 All dynamically allocated data structures for this stream are freed.
535 This function discards any unprocessed input and does not flush any pending
536 output.
537
538 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
539 was inconsistent. In the error case, msg may be set but then points to a
540 static string (which must not be deallocated).
541 */
542
543
544 /* Advanced functions */
545
546 /*
547 The following functions are needed only in some special applications.
548 */
549
550 /*
551 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
552 int level,
553 int method,
554 int windowBits,
555 int memLevel,
556 int strategy));
557
558 This is another version of deflateInit with more compression options. The
559 fields next_in, zalloc, zfree and opaque must be initialized before by the
560 caller.
561
562 The method parameter is the compression method. It must be Z_DEFLATED in
563 this version of the library.
564
565 The windowBits parameter is the base two logarithm of the window size
566 (the size of the history buffer). It should be in the range 8..15 for this
567 version of the library. Larger values of this parameter result in better
568 compression at the expense of memory usage. The default value is 15 if
569 deflateInit is used instead.
570
571 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
572 determines the window size. deflate() will then generate raw deflate data
573 with no zlib header or trailer, and will not compute an adler32 check value.
574
575 windowBits can also be greater than 15 for optional gzip encoding. Add
576 16 to windowBits to write a simple gzip header and trailer around the
577 compressed data instead of a zlib wrapper. The gzip header will have no
578 file name, no extra data, no comment, no modification time (set to zero), no
579 header crc, and the operating system will be set to 255 (unknown). If a
580 gzip stream is being written, strm->adler is a crc32 instead of an adler32.
581
582 The memLevel parameter specifies how much memory should be allocated
583 for the internal compression state. memLevel=1 uses minimum memory but is
584 slow and reduces compression ratio; memLevel=9 uses maximum memory for
585 optimal speed. The default value is 8. See zconf.h for total memory usage
586 as a function of windowBits and memLevel.
587
588 The strategy parameter is used to tune the compression algorithm. Use the
589 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
590 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
591 string match), or Z_RLE to limit match distances to one (run-length
592 encoding). Filtered data consists mostly of small values with a somewhat
593 random distribution. In this case, the compression algorithm is tuned to
594 compress them better. The effect of Z_FILTERED is to force more Huffman
595 coding and less string matching; it is somewhat intermediate between
596 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
597 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
598 strategy parameter only affects the compression ratio but not the
599 correctness of the compressed output even if it is not set appropriately.
600 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
601 decoder for special applications.
602
603 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
604 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
605 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
606 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
607 set to null if there is no error message. deflateInit2 does not perform any
608 compression: this will be done by deflate().
609 */
610
611 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
612 const Bytef *dictionary,
613 uInt dictLength));
614 /*
615 Initializes the compression dictionary from the given byte sequence
616 without producing any compressed output. When using the zlib format, this
617 function must be called immediately after deflateInit, deflateInit2 or
618 deflateReset, and before any call of deflate. When doing raw deflate, this
619 function must be called either before any call of deflate, or immediately
620 after the completion of a deflate block, i.e. after all input has been
621 consumed and all output has been delivered when using any of the flush
622 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
623 compressor and decompressor must use exactly the same dictionary (see
624 inflateSetDictionary).
625
626 The dictionary should consist of strings (byte sequences) that are likely
627 to be encountered later in the data to be compressed, with the most commonly
628 used strings preferably put towards the end of the dictionary. Using a
629 dictionary is most useful when the data to be compressed is short and can be
630 predicted with good accuracy; the data can then be compressed better than
631 with the default empty dictionary.
632
633 Depending on the size of the compression data structures selected by
634 deflateInit or deflateInit2, a part of the dictionary may in effect be
635 discarded, for example if the dictionary is larger than the window size
636 provided in deflateInit or deflateInit2. Thus the strings most likely to be
637 useful should be put at the end of the dictionary, not at the front. In
638 addition, the current implementation of deflate will use at most the window
639 size minus 262 bytes of the provided dictionary.
640
641 Upon return of this function, strm->adler is set to the adler32 value
642 of the dictionary; the decompressor may later use this value to determine
643 which dictionary has been used by the compressor. (The adler32 value
644 applies to the whole dictionary even if only a subset of the dictionary is
645 actually used by the compressor.) If a raw deflate was requested, then the
646 adler32 value is not computed and strm->adler is not set.
647
648 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
649 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
650 inconsistent (for example if deflate has already been called for this stream
651 or if not at a block boundary for raw deflate). deflateSetDictionary does
652 not perform any compression: this will be done by deflate().
653 */
654
655 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
656 z_streamp source));
657 /*
658 Sets the destination stream as a complete copy of the source stream.
659
660 This function can be useful when several compression strategies will be
661 tried, for example when there are several ways of pre-processing the input
662 data with a filter. The streams that will be discarded should then be freed
663 by calling deflateEnd. Note that deflateCopy duplicates the internal
664 compression state which can be quite large, so this strategy is slow and can
665 consume lots of memory.
666
667 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
668 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
669 (such as zalloc being Z_NULL). msg is left unchanged in both source and
670 destination.
671 */
672
673 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
674 /*
675 This function is equivalent to deflateEnd followed by deflateInit,
676 but does not free and reallocate all the internal compression state. The
677 stream will keep the same compression level and any other attributes that
678 may have been set by deflateInit2.
679
680 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
681 stream state was inconsistent (such as zalloc or state being Z_NULL).
682 */
683
684 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
685 int level,
686 int strategy));
687 /*
688 Dynamically update the compression level and compression strategy. The
689 interpretation of level and strategy is as in deflateInit2. This can be
690 used to switch between compression and straight copy of the input data, or
691 to switch to a different kind of input data requiring a different strategy.
692 If the compression level is changed, the input available so far is
693 compressed with the old level (and may be flushed); the new level will take
694 effect only at the next call of deflate().
695
696 Before the call of deflateParams, the stream state must be set as for
697 a call of deflate(), since the currently available input may have to be
698 compressed and flushed. In particular, strm->avail_out must be non-zero.
699
700 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
701 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
702 strm->avail_out was zero.
703 */
704
705 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
706 int good_length,
707 int max_lazy,
708 int nice_length,
709 int max_chain));
710 /*
711 Fine tune deflate's internal compression parameters. This should only be
712 used by someone who understands the algorithm used by zlib's deflate for
713 searching for the best matching string, and even then only by the most
714 fanatic optimizer trying to squeeze out the last compressed bit for their
715 specific input data. Read the deflate.c source code for the meaning of the
716 max_lazy, good_length, nice_length, and max_chain parameters.
717
718 deflateTune() can be called after deflateInit() or deflateInit2(), and
719 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
720 */
721
722 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
723 uLong sourceLen));
724 /*
725 deflateBound() returns an upper bound on the compressed size after
726 deflation of sourceLen bytes. It must be called after deflateInit() or
727 deflateInit2(), and after deflateSetHeader(), if used. This would be used
728 to allocate an output buffer for deflation in a single pass, and so would be
729 called before deflate(). If that first deflate() call is provided the
730 sourceLen input bytes, an output buffer allocated to the size returned by
731 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
732 to return Z_STREAM_END. Note that it is possible for the compressed size to
733 be larger than the value returned by deflateBound() if flush options other
734 than Z_FINISH or Z_NO_FLUSH are used.
735 */
736
737 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
738 unsigned *pending,
739 int *bits));
740 /*
741 deflatePending() returns the number of bytes and bits of output that have
742 been generated, but not yet provided in the available output. The bytes not
743 provided would be due to the available output space having being consumed.
744 The number of bits of output not provided are between 0 and 7, where they
745 await more bits to join them in order to fill out a full byte. If pending
746 or bits are Z_NULL, then those values are not set.
747
748 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
749 stream state was inconsistent.
750 */
751
752 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
753 int bits,
754 int value));
755 /*
756 deflatePrime() inserts bits in the deflate output stream. The intent
757 is that this function is used to start off the deflate output with the bits
758 leftover from a previous deflate stream when appending to it. As such, this
759 function can only be used for raw deflate, and must be used before the first
760 deflate() call after a deflateInit2() or deflateReset(). bits must be less
761 than or equal to 16, and that many of the least significant bits of value
762 will be inserted in the output.
763
764 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
765 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
766 source stream state was inconsistent.
767 */
768
769 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
770 gz_headerp head));
771 /*
772 deflateSetHeader() provides gzip header information for when a gzip
773 stream is requested by deflateInit2(). deflateSetHeader() may be called
774 after deflateInit2() or deflateReset() and before the first call of
775 deflate(). The text, time, os, extra field, name, and comment information
776 in the provided gz_header structure are written to the gzip header (xflag is
777 ignored -- the extra flags are set according to the compression level). The
778 caller must assure that, if not Z_NULL, name and comment are terminated with
779 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
780 available there. If hcrc is true, a gzip header crc is included. Note that
781 the current versions of the command-line version of gzip (up through version
782 1.3.x) do not support header crc's, and will report that it is a "multi-part
783 gzip file" and give up.
784
785 If deflateSetHeader is not used, the default gzip header has text false,
786 the time set to zero, and os set to 255, with no extra, name, or comment
787 fields. The gzip header is returned to the default state by deflateReset().
788
789 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
790 stream state was inconsistent.
791 */
792
793 /*
794 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
795 int windowBits));
796
797 This is another version of inflateInit with an extra parameter. The
798 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
799 before by the caller.
800
801 The windowBits parameter is the base two logarithm of the maximum window
802 size (the size of the history buffer). It should be in the range 8..15 for
803 this version of the library. The default value is 15 if inflateInit is used
804 instead. windowBits must be greater than or equal to the windowBits value
805 provided to deflateInit2() while compressing, or it must be equal to 15 if
806 deflateInit2() was not used. If a compressed stream with a larger window
807 size is given as input, inflate() will return with the error code
808 Z_DATA_ERROR instead of trying to allocate a larger window.
809
810 windowBits can also be zero to request that inflate use the window size in
811 the zlib header of the compressed stream.
812
813 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
814 determines the window size. inflate() will then process raw deflate data,
815 not looking for a zlib or gzip header, not generating a check value, and not
816 looking for any check values for comparison at the end of the stream. This
817 is for use with other formats that use the deflate compressed data format
818 such as zip. Those formats provide their own check values. If a custom
819 format is developed using the raw deflate format for compressed data, it is
820 recommended that a check value such as an adler32 or a crc32 be applied to
821 the uncompressed data as is done in the zlib, gzip, and zip formats. For
822 most applications, the zlib format should be used as is. Note that comments
823 above on the use in deflateInit2() applies to the magnitude of windowBits.
824
825 windowBits can also be greater than 15 for optional gzip decoding. Add
826 32 to windowBits to enable zlib and gzip decoding with automatic header
827 detection, or add 16 to decode only the gzip format (the zlib format will
828 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
829 crc32 instead of an adler32.
830
831 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
832 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
833 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
834 invalid, such as a null pointer to the structure. msg is set to null if
835 there is no error message. inflateInit2 does not perform any decompression
836 apart from possibly reading the zlib header if present: actual decompression
837 will be done by inflate(). (So next_in and avail_in may be modified, but
838 next_out and avail_out are unused and unchanged.) The current implementation
839 of inflateInit2() does not process any header information -- that is
840 deferred until inflate() is called.
841 */
842
843 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
844 const Bytef *dictionary,
845 uInt dictLength));
846 /*
847 Initializes the decompression dictionary from the given uncompressed byte
848 sequence. This function must be called immediately after a call of inflate,
849 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
850 can be determined from the adler32 value returned by that call of inflate.
851 The compressor and decompressor must use exactly the same dictionary (see
852 deflateSetDictionary). For raw inflate, this function can be called at any
853 time to set the dictionary. If the provided dictionary is smaller than the
854 window and there is already data in the window, then the provided dictionary
855 will amend what's there. The application must insure that the dictionary
856 that was used for compression is provided.
857
858 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
859 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
860 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
861 expected one (incorrect adler32 value). inflateSetDictionary does not
862 perform any decompression: this will be done by subsequent calls of
863 inflate().
864 */
865
866 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
867 Bytef *dictionary,
868 uInt *dictLength));
869 /*
870 Returns the sliding dictionary being maintained by inflate. dictLength is
871 set to the number of bytes in the dictionary, and that many bytes are copied
872 to dictionary. dictionary must have enough space, where 32768 bytes is
873 always enough. If inflateGetDictionary() is called with dictionary equal to
874 Z_NULL, then only the dictionary length is returned, and nothing is copied.
875 Similary, if dictLength is Z_NULL, then it is not set.
876
877 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
878 stream state is inconsistent.
879 */
880
881 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
882 /*
883 Skips invalid compressed data until a possible full flush point (see above
884 for the description of deflate with Z_FULL_FLUSH) can be found, or until all
885 available input is skipped. No output is provided.
886
887 inflateSync searches for a 00 00 FF FF pattern in the compressed data.
888 All full flush points have this pattern, but not all occurrences of this
889 pattern are full flush points.
890
891 inflateSync returns Z_OK if a possible full flush point has been found,
892 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
893 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
894 In the success case, the application may save the current current value of
895 total_in which indicates where valid compressed data was found. In the
896 error case, the application may repeatedly call inflateSync, providing more
897 input each time, until success or end of the input data.
898 */
899
900 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
901 z_streamp source));
902 /*
903 Sets the destination stream as a complete copy of the source stream.
904
905 This function can be useful when randomly accessing a large stream. The
906 first pass through the stream can periodically record the inflate state,
907 allowing restarting inflate at those points when randomly accessing the
908 stream.
909
910 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
911 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
912 (such as zalloc being Z_NULL). msg is left unchanged in both source and
913 destination.
914 */
915
916 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
917 /*
918 This function is equivalent to inflateEnd followed by inflateInit,
919 but does not free and reallocate all the internal decompression state. The
920 stream will keep attributes that may have been set by inflateInit2.
921
922 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
923 stream state was inconsistent (such as zalloc or state being Z_NULL).
924 */
925
926 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
927 int windowBits));
928 /*
929 This function is the same as inflateReset, but it also permits changing
930 the wrap and window size requests. The windowBits parameter is interpreted
931 the same as it is for inflateInit2.
932
933 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
934 stream state was inconsistent (such as zalloc or state being Z_NULL), or if
935 the windowBits parameter is invalid.
936 */
937
938 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
939 int bits,
940 int value));
941 /*
942 This function inserts bits in the inflate input stream. The intent is
943 that this function is used to start inflating at a bit position in the
944 middle of a byte. The provided bits will be used before any bytes are used
945 from next_in. This function should only be used with raw inflate, and
946 should be used before the first inflate() call after inflateInit2() or
947 inflateReset(). bits must be less than or equal to 16, and that many of the
948 least significant bits of value will be inserted in the input.
949
950 If bits is negative, then the input stream bit buffer is emptied. Then
951 inflatePrime() can be called again to put bits in the buffer. This is used
952 to clear out bits leftover after feeding inflate a block description prior
953 to feeding inflate codes.
954
955 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
956 stream state was inconsistent.
957 */
958
959 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
960 /*
961 This function returns two values, one in the lower 16 bits of the return
962 value, and the other in the remaining upper bits, obtained by shifting the
963 return value down 16 bits. If the upper value is -1 and the lower value is
964 zero, then inflate() is currently decoding information outside of a block.
965 If the upper value is -1 and the lower value is non-zero, then inflate is in
966 the middle of a stored block, with the lower value equaling the number of
967 bytes from the input remaining to copy. If the upper value is not -1, then
968 it is the number of bits back from the current bit position in the input of
969 the code (literal or length/distance pair) currently being processed. In
970 that case the lower value is the number of bytes already emitted for that
971 code.
972
973 A code is being processed if inflate is waiting for more input to complete
974 decoding of the code, or if it has completed decoding but is waiting for
975 more output space to write the literal or match data.
976
977 inflateMark() is used to mark locations in the input data for random
978 access, which may be at bit positions, and to note those cases where the
979 output of a code may span boundaries of random access blocks. The current
980 location in the input stream can be determined from avail_in and data_type
981 as noted in the description for the Z_BLOCK flush parameter for inflate.
982
983 inflateMark returns the value noted above or -1 << 16 if the provided
984 source stream state was inconsistent.
985 */
986
987 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
988 gz_headerp head));
989 /*
990 inflateGetHeader() requests that gzip header information be stored in the
991 provided gz_header structure. inflateGetHeader() may be called after
992 inflateInit2() or inflateReset(), and before the first call of inflate().
993 As inflate() processes the gzip stream, head->done is zero until the header
994 is completed, at which time head->done is set to one. If a zlib stream is
995 being decoded, then head->done is set to -1 to indicate that there will be
996 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
997 used to force inflate() to return immediately after header processing is
998 complete and before any actual data is decompressed.
999
1000 The text, time, xflags, and os fields are filled in with the gzip header
1001 contents. hcrc is set to true if there is a header CRC. (The header CRC
1002 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
1003 contains the maximum number of bytes to write to extra. Once done is true,
1004 extra_len contains the actual extra field length, and extra contains the
1005 extra field, or that field truncated if extra_max is less than extra_len.
1006 If name is not Z_NULL, then up to name_max characters are written there,
1007 terminated with a zero unless the length is greater than name_max. If
1008 comment is not Z_NULL, then up to comm_max characters are written there,
1009 terminated with a zero unless the length is greater than comm_max. When any
1010 of extra, name, or comment are not Z_NULL and the respective field is not
1011 present in the header, then that field is set to Z_NULL to signal its
1012 absence. This allows the use of deflateSetHeader() with the returned
1013 structure to duplicate the header. However if those fields are set to
1014 allocated memory, then the application will need to save those pointers
1015 elsewhere so that they can be eventually freed.
1016
1017 If inflateGetHeader is not used, then the header information is simply
1018 discarded. The header is always checked for validity, including the header
1019 CRC if present. inflateReset() will reset the process to discard the header
1020 information. The application would need to call inflateGetHeader() again to
1021 retrieve the header from the next gzip stream.
1022
1023 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1024 stream state was inconsistent.
1025 */
1026
1027 /*
1028 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1029 unsigned char FAR *window));
1030
1031 Initialize the internal stream state for decompression using inflateBack()
1032 calls. The fields zalloc, zfree and opaque in strm must be initialized
1033 before the call. If zalloc and zfree are Z_NULL, then the default library-
1034 derived memory allocation routines are used. windowBits is the base two
1035 logarithm of the window size, in the range 8..15. window is a caller
1036 supplied buffer of that size. Except for special applications where it is
1037 assured that deflate was used with small window sizes, windowBits must be 15
1038 and a 32K byte window must be supplied to be able to decompress general
1039 deflate streams.
1040
1041 See inflateBack() for the usage of these routines.
1042
1043 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1044 the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1045 allocated, or Z_VERSION_ERROR if the version of the library does not match
1046 the version of the header file.
1047 */
1048
1049 typedef unsigned (*in_func) OF((void FAR *,
1050 z_const unsigned char FAR * FAR *));
1051 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1052
1053 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1054 in_func in, void FAR *in_desc,
1055 out_func out, void FAR *out_desc));
1056 /*
1057 inflateBack() does a raw inflate with a single call using a call-back
1058 interface for input and output. This is potentially more efficient than
1059 inflate() for file i/o applications, in that it avoids copying between the
1060 output and the sliding window by simply making the window itself the output
1061 buffer. inflate() can be faster on modern CPUs when used with large
1062 buffers. inflateBack() trusts the application to not change the output
1063 buffer passed by the output function, at least until inflateBack() returns.
1064
1065 inflateBackInit() must be called first to allocate the internal state
1066 and to initialize the state with the user-provided window buffer.
1067 inflateBack() may then be used multiple times to inflate a complete, raw
1068 deflate stream with each call. inflateBackEnd() is then called to free the
1069 allocated state.
1070
1071 A raw deflate stream is one with no zlib or gzip header or trailer.
1072 This routine would normally be used in a utility that reads zip or gzip
1073 files and writes out uncompressed files. The utility would decode the
1074 header and process the trailer on its own, hence this routine expects only
1075 the raw deflate stream to decompress. This is different from the normal
1076 behavior of inflate(), which expects either a zlib or gzip header and
1077 trailer around the deflate stream.
1078
1079 inflateBack() uses two subroutines supplied by the caller that are then
1080 called by inflateBack() for input and output. inflateBack() calls those
1081 routines until it reads a complete deflate stream and writes out all of the
1082 uncompressed data, or until it encounters an error. The function's
1083 parameters and return types are defined above in the in_func and out_func
1084 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1085 number of bytes of provided input, and a pointer to that input in buf. If
1086 there is no input available, in() must return zero--buf is ignored in that
1087 case--and inflateBack() will return a buffer error. inflateBack() will call
1088 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
1089 should return zero on success, or non-zero on failure. If out() returns
1090 non-zero, inflateBack() will return with an error. Neither in() nor out()
1091 are permitted to change the contents of the window provided to
1092 inflateBackInit(), which is also the buffer that out() uses to write from.
1093 The length written by out() will be at most the window size. Any non-zero
1094 amount of input may be provided by in().
1095
1096 For convenience, inflateBack() can be provided input on the first call by
1097 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1098 in() will be called. Therefore strm->next_in must be initialized before
1099 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1100 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1101 must also be initialized, and then if strm->avail_in is not zero, input will
1102 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1103
1104 The in_desc and out_desc parameters of inflateBack() is passed as the
1105 first parameter of in() and out() respectively when they are called. These
1106 descriptors can be optionally used to pass any information that the caller-
1107 supplied in() and out() functions need to do their job.
1108
1109 On return, inflateBack() will set strm->next_in and strm->avail_in to
1110 pass back any unused input that was provided by the last in() call. The
1111 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1112 if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1113 in the deflate stream (in which case strm->msg is set to indicate the nature
1114 of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1115 In the case of Z_BUF_ERROR, an input or output error can be distinguished
1116 using strm->next_in which will be Z_NULL only if in() returned an error. If
1117 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1118 non-zero. (in() will always be called before out(), so strm->next_in is
1119 assured to be defined if out() returns non-zero.) Note that inflateBack()
1120 cannot return Z_OK.
1121 */
1122
1123 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1124 /*
1125 All memory allocated by inflateBackInit() is freed.
1126
1127 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1128 state was inconsistent.
1129 */
1130
1131 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1132 /* Return flags indicating compile-time options.
1133
1134 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1135 1.0: size of uInt
1136 3.2: size of uLong
1137 5.4: size of voidpf (pointer)
1138 7.6: size of z_off_t
1139
1140 Compiler, assembler, and debug options:
1141 8: DEBUG
1142 9: ASMV or ASMINF -- use ASM code
1143 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1144 11: 0 (reserved)
1145
1146 One-time table building (smaller code, but not thread-safe if true):
1147 12: BUILDFIXED -- build static block decoding tables when needed
1148 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1149 14,15: 0 (reserved)
1150
1151 Library content (indicates missing functionality):
1152 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1153 deflate code when not needed)
1154 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1155 and decode gzip streams (to avoid linking crc code)
1156 18-19: 0 (reserved)
1157
1158 Operation variations (changes in library functionality):
1159 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1160 21: FASTEST -- deflate algorithm with only one, lowest compression level
1161 22,23: 0 (reserved)
1162
1163 The sprintf variant used by gzprintf (zero is best):
1164 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1165 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1166 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1167
1168 Remainder:
1169 27-31: 0 (reserved)
1170 */
1171
1172 #ifndef Z_SOLO
1173
1174 /* utility functions */
1175
1176 /*
1177 The following utility functions are implemented on top of the basic
1178 stream-oriented functions. To simplify the interface, some default options
1179 are assumed (compression level and memory usage, standard memory allocation
1180 functions). The source code of these utility functions can be modified if
1181 you need special options.
1182 */
1183
1184 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1185 const Bytef *source, uLong sourceLen));
1186 /*
1187 Compresses the source buffer into the destination buffer. sourceLen is
1188 the byte length of the source buffer. Upon entry, destLen is the total size
1189 of the destination buffer, which must be at least the value returned by
1190 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1191 compressed buffer.
1192
1193 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1194 enough memory, Z_BUF_ERROR if there was not enough room in the output
1195 buffer.
1196 */
1197
1198 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1199 const Bytef *source, uLong sourceLen,
1200 int level));
1201 /*
1202 Compresses the source buffer into the destination buffer. The level
1203 parameter has the same meaning as in deflateInit. sourceLen is the byte
1204 length of the source buffer. Upon entry, destLen is the total size of the
1205 destination buffer, which must be at least the value returned by
1206 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1207 compressed buffer.
1208
1209 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1210 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1211 Z_STREAM_ERROR if the level parameter is invalid.
1212 */
1213
1214 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1215 /*
1216 compressBound() returns an upper bound on the compressed size after
1217 compress() or compress2() on sourceLen bytes. It would be used before a
1218 compress() or compress2() call to allocate the destination buffer.
1219 */
1220
1221 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1222 const Bytef *source, uLong sourceLen));
1223 /*
1224 Decompresses the source buffer into the destination buffer. sourceLen is
1225 the byte length of the source buffer. Upon entry, destLen is the total size
1226 of the destination buffer, which must be large enough to hold the entire
1227 uncompressed data. (The size of the uncompressed data must have been saved
1228 previously by the compressor and transmitted to the decompressor by some
1229 mechanism outside the scope of this compression library.) Upon exit, destLen
1230 is the actual size of the uncompressed buffer.
1231
1232 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1233 enough memory, Z_BUF_ERROR if there was not enough room in the output
1234 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1235 the case where there is not enough room, uncompress() will fill the output
1236 buffer with the uncompressed data up to that point.
1237 */
1238
1239 /* gzip file access functions */
1240
1241 /*
1242 This library supports reading and writing files in gzip (.gz) format with
1243 an interface similar to that of stdio, using the functions that start with
1244 "gz". The gzip format is different from the zlib format. gzip is a gzip
1245 wrapper, documented in RFC 1952, wrapped around a deflate stream.
1246 */
1247
1248 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1249
1250 /*
1251 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1252
1253 Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1254 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1255 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1256 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1257 for fixed code compression as in "wb9F". (See the description of
1258 deflateInit2 for more information about the strategy parameter.) 'T' will
1259 request transparent writing or appending with no compression and not using
1260 the gzip format.
1261
1262 "a" can be used instead of "w" to request that the gzip stream that will
1263 be written be appended to the file. "+" will result in an error, since
1264 reading and writing to the same gzip file is not supported. The addition of
1265 "x" when writing will create the file exclusively, which fails if the file
1266 already exists. On systems that support it, the addition of "e" when
1267 reading or writing will set the flag to close the file on an execve() call.
1268
1269 These functions, as well as gzip, will read and decode a sequence of gzip
1270 streams in a file. The append function of gzopen() can be used to create
1271 such a file. (Also see gzflush() for another way to do this.) When
1272 appending, gzopen does not test whether the file begins with a gzip stream,
1273 nor does it look for the end of the gzip streams to begin appending. gzopen
1274 will simply append a gzip stream to the existing file.
1275
1276 gzopen can be used to read a file which is not in gzip format; in this
1277 case gzread will directly read from the file without decompression. When
1278 reading, this will be detected automatically by looking for the magic two-
1279 byte gzip header.
1280
1281 gzopen returns NULL if the file could not be opened, if there was
1282 insufficient memory to allocate the gzFile state, or if an invalid mode was
1283 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1284 errno can be checked to determine if the reason gzopen failed was that the
1285 file could not be opened.
1286 */
1287
1288 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1289 /*
1290 gzdopen associates a gzFile with the file descriptor fd. File descriptors
1291 are obtained from calls like open, dup, creat, pipe or fileno (if the file
1292 has been previously opened with fopen). The mode parameter is as in gzopen.
1293
1294 The next call of gzclose on the returned gzFile will also close the file
1295 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1296 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1297 mode);. The duplicated descriptor should be saved to avoid a leak, since
1298 gzdopen does not close fd if it fails. If you are using fileno() to get the
1299 file descriptor from a FILE *, then you will have to use dup() to avoid
1300 double-close()ing the file descriptor. Both gzclose() and fclose() will
1301 close the associated file descriptor, so they need to have different file
1302 descriptors.
1303
1304 gzdopen returns NULL if there was insufficient memory to allocate the
1305 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1306 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1307 used until the next gz* read, write, seek, or close operation, so gzdopen
1308 will not detect if fd is invalid (unless fd is -1).
1309 */
1310
1311 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1312 /*
1313 Set the internal buffer size used by this library's functions. The
1314 default buffer size is 8192 bytes. This function must be called after
1315 gzopen() or gzdopen(), and before any other calls that read or write the
1316 file. The buffer memory allocation is always deferred to the first read or
1317 write. Two buffers are allocated, either both of the specified size when
1318 writing, or one of the specified size and the other twice that size when
1319 reading. A larger buffer size of, for example, 64K or 128K bytes will
1320 noticeably increase the speed of decompression (reading).
1321
1322 The new buffer size also affects the maximum length for gzprintf().
1323
1324 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1325 too late.
1326 */
1327
1328 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1329 /*
1330 Dynamically update the compression level or strategy. See the description
1331 of deflateInit2 for the meaning of these parameters.
1332
1333 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1334 opened for writing.
1335 */
1336
1337 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1338 /*
1339 Reads the given number of uncompressed bytes from the compressed file. If
1340 the input file is not in gzip format, gzread copies the given number of
1341 bytes into the buffer directly from the file.
1342
1343 After reaching the end of a gzip stream in the input, gzread will continue
1344 to read, looking for another gzip stream. Any number of gzip streams may be
1345 concatenated in the input file, and will all be decompressed by gzread().
1346 If something other than a gzip stream is encountered after a gzip stream,
1347 that remaining trailing garbage is ignored (and no error is returned).
1348
1349 gzread can be used to read a gzip file that is being concurrently written.
1350 Upon reaching the end of the input, gzread will return with the available
1351 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1352 gzclearerr can be used to clear the end of file indicator in order to permit
1353 gzread to be tried again. Z_OK indicates that a gzip stream was completed
1354 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1355 middle of a gzip stream. Note that gzread does not return -1 in the event
1356 of an incomplete gzip stream. This error is deferred until gzclose(), which
1357 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1358 stream. Alternatively, gzerror can be used before gzclose to detect this
1359 case.
1360
1361 gzread returns the number of uncompressed bytes actually read, less than
1362 len for end of file, or -1 for error.
1363 */
1364
1365 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1366 voidpc buf, unsigned len));
1367 /*
1368 Writes the given number of uncompressed bytes into the compressed file.
1369 gzwrite returns the number of uncompressed bytes written or 0 in case of
1370 error.
1371 */
1372
1373 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1374 /*
1375 Converts, formats, and writes the arguments to the compressed file under
1376 control of the format string, as in fprintf. gzprintf returns the number of
1377 uncompressed bytes actually written, or 0 in case of error. The number of
1378 uncompressed bytes written is limited to 8191, or one less than the buffer
1379 size given to gzbuffer(). The caller should assure that this limit is not
1380 exceeded. If it is exceeded, then gzprintf() will return an error (0) with
1381 nothing written. In this case, there may also be a buffer overflow with
1382 unpredictable consequences, which is possible only if zlib was compiled with
1383 the insecure functions sprintf() or vsprintf() because the secure snprintf()
1384 or vsnprintf() functions were not available. This can be determined using
1385 zlibCompileFlags().
1386 */
1387
1388 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1389 /*
1390 Writes the given null-terminated string to the compressed file, excluding
1391 the terminating null character.
1392
1393 gzputs returns the number of characters written, or -1 in case of error.
1394 */
1395
1396 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1397 /*
1398 Reads bytes from the compressed file until len-1 characters are read, or a
1399 newline character is read and transferred to buf, or an end-of-file
1400 condition is encountered. If any characters are read or if len == 1, the
1401 string is terminated with a null character. If no characters are read due
1402 to an end-of-file or len < 1, then the buffer is left untouched.
1403
1404 gzgets returns buf which is a null-terminated string, or it returns NULL
1405 for end-of-file or in case of error. If there was an error, the contents at
1406 buf are indeterminate.
1407 */
1408
1409 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1410 /*
1411 Writes c, converted to an unsigned char, into the compressed file. gzputc
1412 returns the value that was written, or -1 in case of error.
1413 */
1414
1415 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1416 /*
1417 Reads one byte from the compressed file. gzgetc returns this byte or -1
1418 in case of end of file or error. This is implemented as a macro for speed.
1419 As such, it does not do all of the checking the other functions do. I.e.
1420 it does not check to see if file is NULL, nor whether the structure file
1421 points to has been clobbered or not.
1422 */
1423
1424 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1425 /*
1426 Push one character back onto the stream to be read as the first character
1427 on the next read. At least one character of push-back is allowed.
1428 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1429 fail if c is -1, and may fail if a character has been pushed but not read
1430 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1431 output buffer size of pushed characters is allowed. (See gzbuffer above.)
1432 The pushed character will be discarded if the stream is repositioned with
1433 gzseek() or gzrewind().
1434 */
1435
1436 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1437 /*
1438 Flushes all pending output into the compressed file. The parameter flush
1439 is as in the deflate() function. The return value is the zlib error number
1440 (see function gzerror below). gzflush is only permitted when writing.
1441
1442 If the flush parameter is Z_FINISH, the remaining data is written and the
1443 gzip stream is completed in the output. If gzwrite() is called again, a new
1444 gzip stream will be started in the output. gzread() is able to read such
1445 concatented gzip streams.
1446
1447 gzflush should be called only when strictly necessary because it will
1448 degrade compression if called too often.
1449 */
1450
1451 /*
1452 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1453 z_off_t offset, int whence));
1454
1455 Sets the starting position for the next gzread or gzwrite on the given
1456 compressed file. The offset represents a number of bytes in the
1457 uncompressed data stream. The whence parameter is defined as in lseek(2);
1458 the value SEEK_END is not supported.
1459
1460 If the file is opened for reading, this function is emulated but can be
1461 extremely slow. If the file is opened for writing, only forward seeks are
1462 supported; gzseek then compresses a sequence of zeroes up to the new
1463 starting position.
1464
1465 gzseek returns the resulting offset location as measured in bytes from
1466 the beginning of the uncompressed stream, or -1 in case of error, in
1467 particular if the file is opened for writing and the new starting position
1468 would be before the current position.
1469 */
1470
1471 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1472 /*
1473 Rewinds the given file. This function is supported only for reading.
1474
1475 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1476 */
1477
1478 /*
1479 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1480
1481 Returns the starting position for the next gzread or gzwrite on the given
1482 compressed file. This position represents a number of bytes in the
1483 uncompressed data stream, and is zero when starting, even if appending or
1484 reading a gzip stream from the middle of a file using gzdopen().
1485
1486 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1487 */
1488
1489 /*
1490 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1491
1492 Returns the current offset in the file being read or written. This offset
1493 includes the count of bytes that precede the gzip stream, for example when
1494 appending or when using gzdopen() for reading. When reading, the offset
1495 does not include as yet unused buffered input. This information can be used
1496 for a progress indicator. On error, gzoffset() returns -1.
1497 */
1498
1499 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1500 /*
1501 Returns true (1) if the end-of-file indicator has been set while reading,
1502 false (0) otherwise. Note that the end-of-file indicator is set only if the
1503 read tried to go past the end of the input, but came up short. Therefore,
1504 just like feof(), gzeof() may return false even if there is no more data to
1505 read, in the event that the last read request was for the exact number of
1506 bytes remaining in the input file. This will happen if the input file size
1507 is an exact multiple of the buffer size.
1508
1509 If gzeof() returns true, then the read functions will return no more data,
1510 unless the end-of-file indicator is reset by gzclearerr() and the input file
1511 has grown since the previous end of file was detected.
1512 */
1513
1514 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1515 /*
1516 Returns true (1) if file is being copied directly while reading, or false
1517 (0) if file is a gzip stream being decompressed.
1518
1519 If the input file is empty, gzdirect() will return true, since the input
1520 does not contain a gzip stream.
1521
1522 If gzdirect() is used immediately after gzopen() or gzdopen() it will
1523 cause buffers to be allocated to allow reading the file to determine if it
1524 is a gzip file. Therefore if gzbuffer() is used, it should be called before
1525 gzdirect().
1526
1527 When writing, gzdirect() returns true (1) if transparent writing was
1528 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1529 gzdirect() is not needed when writing. Transparent writing must be
1530 explicitly requested, so the application already knows the answer. When
1531 linking statically, using gzdirect() will include all of the zlib code for
1532 gzip file reading and decompression, which may not be desired.)
1533 */
1534
1535 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1536 /*
1537 Flushes all pending output if necessary, closes the compressed file and
1538 deallocates the (de)compression state. Note that once file is closed, you
1539 cannot call gzerror with file, since its structures have been deallocated.
1540 gzclose must not be called more than once on the same file, just as free
1541 must not be called more than once on the same allocation.
1542
1543 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1544 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1545 last read ended in the middle of a gzip stream, or Z_OK on success.
1546 */
1547
1548 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1549 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1550 /*
1551 Same as gzclose(), but gzclose_r() is only for use when reading, and
1552 gzclose_w() is only for use when writing or appending. The advantage to
1553 using these instead of gzclose() is that they avoid linking in zlib
1554 compression or decompression code that is not used when only reading or only
1555 writing respectively. If gzclose() is used, then both compression and
1556 decompression code will be included the application when linking to a static
1557 zlib library.
1558 */
1559
1560 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1561 /*
1562 Returns the error message for the last error which occurred on the given
1563 compressed file. errnum is set to zlib error number. If an error occurred
1564 in the file system and not in the compression library, errnum is set to
1565 Z_ERRNO and the application may consult errno to get the exact error code.
1566
1567 The application must not modify the returned string. Future calls to
1568 this function may invalidate the previously returned string. If file is
1569 closed, then the string previously returned by gzerror will no longer be
1570 available.
1571
1572 gzerror() should be used to distinguish errors from end-of-file for those
1573 functions above that do not distinguish those cases in their return values.
1574 */
1575
1576 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1577 /*
1578 Clears the error and end-of-file flags for file. This is analogous to the
1579 clearerr() function in stdio. This is useful for continuing to read a gzip
1580 file that is being written concurrently.
1581 */
1582
1583 #endif /* !Z_SOLO */
1584
1585 /* checksum functions */
1586
1587 /*
1588 These functions are not related to compression but are exported
1589 anyway because they might be useful in applications using the compression
1590 library.
1591 */
1592
1593 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1594 /*
1595 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1596 return the updated checksum. If buf is Z_NULL, this function returns the
1597 required initial value for the checksum.
1598
1599 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1600 much faster.
1601
1602 Usage example:
1603
1604 uLong adler = adler32(0L, Z_NULL, 0);
1605
1606 while (read_buffer(buffer, length) != EOF) {
1607 adler = adler32(adler, buffer, length);
1608 }
1609 if (adler != original_adler) error();
1610 */
1611
1612 /*
1613 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1614 z_off_t len2));
1615
1616 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1617 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1618 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1619 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1620 that the z_off_t type (like off_t) is a signed integer. If len2 is
1621 negative, the result has no meaning or utility.
1622 */
1623
1624 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1625 /*
1626 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1627 updated CRC-32. If buf is Z_NULL, this function returns the required
1628 initial value for the crc. Pre- and post-conditioning (one's complement) is
1629 performed within this function so it shouldn't be done by the application.
1630
1631 Usage example:
1632
1633 uLong crc = crc32(0L, Z_NULL, 0);
1634
1635 while (read_buffer(buffer, length) != EOF) {
1636 crc = crc32(crc, buffer, length);
1637 }
1638 if (crc != original_crc) error();
1639 */
1640
1641 /*
1642 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1643
1644 Combine two CRC-32 check values into one. For two sequences of bytes,
1645 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1646 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1647 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1648 len2.
1649 */
1650
1651
1652 /* various hacks, don't look :) */
1653
1654 /* deflateInit and inflateInit are macros to allow checking the zlib version
1655 * and the compiler's view of z_stream:
1656 */
1657 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1658 const char *version, int stream_size));
1659 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1660 const char *version, int stream_size));
1661 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1662 int windowBits, int memLevel,
1663 int strategy, const char *version,
1664 int stream_size));
1665 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1666 const char *version, int stream_size));
1667 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1668 unsigned char FAR *window,
1669 const char *version,
1670 int stream_size));
1671 #define deflateInit(strm, level) \
1672 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1673 #define inflateInit(strm) \
1674 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1675 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1676 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1677 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1678 #define inflateInit2(strm, windowBits) \
1679 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1680 (int)sizeof(z_stream))
1681 #define inflateBackInit(strm, windowBits, window) \
1682 inflateBackInit_((strm), (windowBits), (window), \
1683 ZLIB_VERSION, (int)sizeof(z_stream))
1684
1685 #ifndef Z_SOLO
1686
1687 /* gzgetc() macro and its supporting function and exposed data structure. Note
1688 * that the real internal state is much larger than the exposed structure.
1689 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1690 * user should not mess with these exposed elements, since their names or
1691 * behavior could change in the future, perhaps even capriciously. They can
1692 * only be used by the gzgetc() macro. You have been warned.
1693 */
1694 struct gzFile_s {
1695 unsigned have;
1696 unsigned char *next;
1697 z_off64_t pos;
1698 };
1699 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
1700 #ifdef Z_PREFIX_SET
1701 # undef z_gzgetc
1702 # define z_gzgetc(g) \
1703 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1704 #else
1705 # define gzgetc(g) \
1706 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1707 #endif
1708
1709 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1710 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1711 * both are true, the application gets the *64 functions, and the regular
1712 * functions are changed to 64 bits) -- in case these are set on systems
1713 * without large file support, _LFS64_LARGEFILE must also be true
1714 */
1715 #ifdef Z_LARGE64
1716 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1717 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1718 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1719 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1720 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1721 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1722 #endif
1723
1724 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1725 # ifdef Z_PREFIX_SET
1726 # define z_gzopen z_gzopen64
1727 # define z_gzseek z_gzseek64
1728 # define z_gztell z_gztell64
1729 # define z_gzoffset z_gzoffset64
1730 # define z_adler32_combine z_adler32_combine64
1731 # define z_crc32_combine z_crc32_combine64
1732 # else
1733 # define gzopen gzopen64
1734 # define gzseek gzseek64
1735 # define gztell gztell64
1736 # define gzoffset gzoffset64
1737 # define adler32_combine adler32_combine64
1738 # define crc32_combine crc32_combine64
1739 # endif
1740 # ifndef Z_LARGE64
1741 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1742 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1743 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1744 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1745 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1746 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1747 # endif
1748 #else
1749 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1750 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1751 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1752 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1753 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1754 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1755 #endif
1756
1757 #else /* Z_SOLO */
1758
1759 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1760 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1761
1762 #endif /* !Z_SOLO */
1763
1764 /* hack for buggy compilers */
1765 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1766 struct internal_state {int dummy;};
1767 #endif
1768
1769 /* undocumented functions */
1770 ZEXTERN const char * ZEXPORT zError OF((int));
1771 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1772 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1773 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1774 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1775 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1776 #if defined(_WIN32) && !defined(Z_SOLO)
1777 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1778 const char *mode));
1779 #endif
1780 #if defined(STDC) || defined(Z_HAVE_STDARG_H)
1781 # ifndef Z_SOLO
1782 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1783 const char *format,
1784 va_list va));
1785 # endif
1786 #endif
1787
1788 #ifdef __cplusplus
1789 }
1790 #endif
1791
1792 #endif /* ZLIB_H */