1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.2.8, April 28th, 2013
3
4 Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
5
6 This software is provided 'as-is', without any express or implied
7 warranty. In no event will the authors be held liable for any damages
8 arising from the use of this software.
9
10 Permission is granted to anyone to use this software for any purpose,
11 including commercial applications, and to alter it and redistribute it
12 freely, subject to the following restrictions:
13
14 1. The origin of this software must not be misrepresented; you must not
15 claim that you wrote the original software. If you use this software
16 in a product, an acknowledgment in the product documentation would be
17 appreciated but is not required.
18 2. Altered source versions must be plainly marked as such, and must not be
19 misrepresented as being the original software.
20 3. This notice may not be removed or altered from any source distribution.
21
22 Jean-loup Gailly Mark Adler
23 jloup@gzip.org madler@alumni.caltech.edu
24
25
26 The data format used by the zlib library is described by RFCs (Request for
27 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
28 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
29 */
30
31 #ifndef ZLIB_H
32 #define ZLIB_H
33
34 #include "zconf.h"
35
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39
40 #define ZLIB_VERSION "1.2.8"
41 #define ZLIB_VERNUM 0x1280
42 #define ZLIB_VER_MAJOR 1
43 #define ZLIB_VER_MINOR 2
44 #define ZLIB_VER_REVISION 8
45 #define ZLIB_VER_SUBREVISION 0
46
47 /*
48 The 'zlib' compression library provides in-memory compression and
49 decompression functions, including integrity checks of the uncompressed data.
50 This version of the library supports only one compression method (deflation)
51 but other algorithms will be added later and will have the same stream
52 interface.
53
54 Compression can be done in a single step if the buffers are large enough,
55 or can be done by repeated calls of the compression function. In the latter
56 case, the application must provide more input and/or consume the output
57 (providing more output space) before each call.
58
59 The compressed data format used by default by the in-memory functions is
60 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
61 around a deflate stream, which is itself documented in RFC 1951.
62
63 The library also supports reading and writing files in gzip (.gz) format
64 with an interface similar to that of stdio using the functions that start
65 with "gz". The gzip format is different from the zlib format. gzip is a
66 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
67
68 This library can optionally read and write gzip streams in memory as well.
69
70 The zlib format was designed to be compact and fast for use in memory
71 and on communications channels. The gzip format was designed for single-
72 file compression on file systems, has a larger header than zlib to maintain
73 directory information, and uses a different, slower check method than zlib.
74
75 The library does not install any signal handler. The decoder checks
76 the consistency of the compressed data, so the library should never crash
77 even in case of corrupted input.
78 */
79
80 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
81 typedef void (*free_func) OF((voidpf opaque, voidpf address));
82
83 struct internal_state;
84
85 typedef struct z_stream_s {
86 z_const Bytef *next_in; /* next input byte */
87 uInt avail_in; /* number of bytes available at next_in */
88 uLong total_in; /* total number of input bytes read so far */
89
90 Bytef *next_out; /* next output byte should be put there */
91 uInt avail_out; /* remaining free space at next_out */
92 uLong total_out; /* total number of bytes output so far */
93
94 z_const char *msg; /* last error message, NULL if no error */
95 struct internal_state FAR *state; /* not visible by applications */
96
97 alloc_func zalloc; /* used to allocate the internal state */
98 free_func zfree; /* used to free the internal state */
99 voidpf opaque; /* private data object passed to zalloc and zfree */
100
101 int data_type; /* best guess about the data type: binary or text */
102 uLong adler; /* adler32 value of the uncompressed data */
103 uLong reserved; /* reserved for future use */
104 } z_stream;
105
106 typedef z_stream FAR *z_streamp;
107
108 /*
109 gzip header information passed to and from zlib routines. See RFC 1952
110 for more details on the meanings of these fields.
111 */
112 typedef struct gz_header_s {
113 int text; /* true if compressed data believed to be text */
114 uLong time; /* modification time */
115 int xflags; /* extra flags (not used when writing a gzip file) */
116 int os; /* operating system */
117 Bytef *extra; /* pointer to extra field or Z_NULL if none */
118 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
119 uInt extra_max; /* space at extra (only when reading header) */
120 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
121 uInt name_max; /* space at name (only when reading header) */
122 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
123 uInt comm_max; /* space at comment (only when reading header) */
124 int hcrc; /* true if there was or will be a header crc */
125 int done; /* true when done reading gzip header (not used
126 when writing a gzip file) */
127 } gz_header;
128
129 typedef gz_header FAR *gz_headerp;
130
131 /*
132 The application must update next_in and avail_in when avail_in has dropped
133 to zero. It must update next_out and avail_out when avail_out has dropped
134 to zero. The application must initialize zalloc, zfree and opaque before
135 calling the init function. All other fields are set by the compression
136 library and must not be updated by the application.
137
138 The opaque value provided by the application will be passed as the first
139 parameter for calls of zalloc and zfree. This can be useful for custom
140 memory management. The compression library attaches no meaning to the
141 opaque value.
142
143 zalloc must return Z_NULL if there is not enough memory for the object.
144 If zlib is used in a multi-threaded application, zalloc and zfree must be
145 thread safe.
146
147 On 16-bit systems, the functions zalloc and zfree must be able to allocate
148 exactly 65536 bytes, but will not be required to allocate more than this if
149 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
150 returned by zalloc for objects of exactly 65536 bytes *must* have their
151 offset normalized to zero. The default allocation function provided by this
152 library ensures this (see zutil.c). To reduce memory requirements and avoid
153 any allocation of 64K objects, at the expense of compression ratio, compile
154 the library with -DMAX_WBITS=14 (see zconf.h).
155
156 The fields total_in and total_out can be used for statistics or progress
157 reports. After compression, total_in holds the total size of the
158 uncompressed data and may be saved for use in the decompressor (particularly
159 if the decompressor wants to decompress everything in a single step).
160 */
161
162 /* constants */
163
164 #define Z_NO_FLUSH 0
165 #define Z_PARTIAL_FLUSH 1
166 #define Z_SYNC_FLUSH 2
167 #define Z_FULL_FLUSH 3
168 #define Z_FINISH 4
169 #define Z_BLOCK 5
170 #define Z_TREES 6
171 /* Allowed flush values; see deflate() and inflate() below for details */
172
173 #define Z_OK 0
174 #define Z_STREAM_END 1
175 #define Z_NEED_DICT 2
176 #define Z_ERRNO (-1)
177 #define Z_STREAM_ERROR (-2)
178 #define Z_DATA_ERROR (-3)
179 #define Z_MEM_ERROR (-4)
180 #define Z_BUF_ERROR (-5)
181 #define Z_VERSION_ERROR (-6)
182 /* Return codes for the compression/decompression functions. Negative values
183 * are errors, positive values are used for special but normal events.
184 */
185
186 #define Z_NO_COMPRESSION 0
187 #define Z_BEST_SPEED 1
188 #define Z_BEST_COMPRESSION 9
189 #define Z_DEFAULT_COMPRESSION (-1)
190 /* compression levels */
191
192 #define Z_FILTERED 1
193 #define Z_HUFFMAN_ONLY 2
194 #define Z_RLE 3
195 #define Z_FIXED 4
196 #define Z_DEFAULT_STRATEGY 0
197 /* compression strategy; see deflateInit2() below for details */
198
199 #define Z_BINARY 0
200 #define Z_TEXT 1
201 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
202 #define Z_UNKNOWN 2
203 /* Possible values of the data_type field (though see inflate()) */
204
205 #define Z_DEFLATED 8
206 /* The deflate compression method (the only one supported in this version) */
207
208 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
209
210 #define zlib_version zlibVersion()
211 /* for compatibility with versions < 1.0.2 */
212
213
214 /* basic functions */
215
216 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
217 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
218 If the first character differs, the library code actually used is not
219 compatible with the zlib.h header file used by the application. This check
220 is automatically made by deflateInit and inflateInit.
221 */
222
223 /*
224 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
225
226 Initializes the internal stream state for compression. The fields
227 zalloc, zfree and opaque must be initialized before by the caller. If
228 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
229 allocation functions.
230
231 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
232 1 gives best speed, 9 gives best compression, 0 gives no compression at all
233 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
234 requests a default compromise between speed and compression (currently
235 equivalent to level 6).
236
237 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
238 memory, Z_STREAM_ERROR if level is not a valid compression level, or
239 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
240 with the version assumed by the caller (ZLIB_VERSION). msg is set to null
241 if there is no error message. deflateInit does not perform any compression:
242 this will be done by deflate().
243 */
244
245
246 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
247 /*
248 deflate compresses as much data as possible, and stops when the input
249 buffer becomes empty or the output buffer becomes full. It may introduce
250 some output latency (reading input without producing any output) except when
251 forced to flush.
252
253 The detailed semantics are as follows. deflate performs one or both of the
254 following actions:
255
256 - Compress more input starting at next_in and update next_in and avail_in
257 accordingly. If not all input can be processed (because there is not
258 enough room in the output buffer), next_in and avail_in are updated and
259 processing will resume at this point for the next call of deflate().
260
261 - Provide more output starting at next_out and update next_out and avail_out
262 accordingly. This action is forced if the parameter flush is non zero.
263 Forcing flush frequently degrades the compression ratio, so this parameter
264 should be set only when necessary (in interactive applications). Some
265 output may be provided even if flush is not set.
266
267 Before the call of deflate(), the application should ensure that at least
268 one of the actions is possible, by providing more input and/or consuming more
269 output, and updating avail_in or avail_out accordingly; avail_out should
270 never be zero before the call. The application can consume the compressed
271 output when it wants, for example when the output buffer is full (avail_out
272 == 0), or after each call of deflate(). If deflate returns Z_OK and with
273 zero avail_out, it must be called again after making room in the output
274 buffer because there might be more output pending.
275
276 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
277 decide how much data to accumulate before producing output, in order to
278 maximize compression.
279
280 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
281 flushed to the output buffer and the output is aligned on a byte boundary, so
282 that the decompressor can get all input data available so far. (In
283 particular avail_in is zero after the call if enough output space has been
284 provided before the call.) Flushing may degrade compression for some
285 compression algorithms and so it should be used only when necessary. This
286 completes the current deflate block and follows it with an empty stored block
287 that is three bits plus filler bits to the next byte, followed by four bytes
288 (00 00 ff ff).
289
290 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
291 output buffer, but the output is not aligned to a byte boundary. All of the
292 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
293 This completes the current deflate block and follows it with an empty fixed
294 codes block that is 10 bits long. This assures that enough bytes are output
295 in order for the decompressor to finish the block before the empty fixed code
296 block.
297
298 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
299 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
300 seven bits of the current block are held to be written as the next byte after
301 the next deflate block is completed. In this case, the decompressor may not
302 be provided enough bits at this point in order to complete decompression of
303 the data provided so far to the compressor. It may need to wait for the next
304 block to be emitted. This is for advanced applications that need to control
305 the emission of deflate blocks.
306
307 If flush is set to Z_FULL_FLUSH, all output is flushed as with
308 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
309 restart from this point if previous compressed data has been damaged or if
310 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
311 compression.
312
313 If deflate returns with avail_out == 0, this function must be called again
314 with the same value of the flush parameter and more output space (updated
315 avail_out), until the flush is complete (deflate returns with non-zero
316 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
317 avail_out is greater than six to avoid repeated flush markers due to
318 avail_out == 0 on return.
319
320 If the parameter flush is set to Z_FINISH, pending input is processed,
321 pending output is flushed and deflate returns with Z_STREAM_END if there was
322 enough output space; if deflate returns with Z_OK, this function must be
323 called again with Z_FINISH and more output space (updated avail_out) but no
324 more input data, until it returns with Z_STREAM_END or an error. After
325 deflate has returned Z_STREAM_END, the only possible operations on the stream
326 are deflateReset or deflateEnd.
327
328 Z_FINISH can be used immediately after deflateInit if all the compression
329 is to be done in a single step. In this case, avail_out must be at least the
330 value returned by deflateBound (see below). Then deflate is guaranteed to
331 return Z_STREAM_END. If not enough output space is provided, deflate will
332 not return Z_STREAM_END, and it must be called again as described above.
333
334 deflate() sets strm->adler to the adler32 checksum of all input read
335 so far (that is, total_in bytes).
336
337 deflate() may update strm->data_type if it can make a good guess about
338 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
339 binary. This field is only for information purposes and does not affect the
340 compression algorithm in any manner.
341
342 deflate() returns Z_OK if some progress has been made (more input
343 processed or more output produced), Z_STREAM_END if all input has been
344 consumed and all output has been produced (only when flush is set to
345 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
346 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
347 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
348 fatal, and deflate() can be called again with more input and more output
349 space to continue compressing.
350 */
351
352
353 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
354 /*
355 All dynamically allocated data structures for this stream are freed.
356 This function discards any unprocessed input and does not flush any pending
357 output.
358
359 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
360 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
361 prematurely (some input or output was discarded). In the error case, msg
362 may be set but then points to a static string (which must not be
363 deallocated).
364 */
365
366
367 /*
368 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
369
370 Initializes the internal stream state for decompression. The fields
371 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
372 the caller. If next_in is not Z_NULL and avail_in is large enough (the
373 exact value depends on the compression method), inflateInit determines the
374 compression method from the zlib header and allocates all data structures
375 accordingly; otherwise the allocation will be deferred to the first call of
376 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
377 use default allocation functions.
378
379 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
380 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
381 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
382 invalid, such as a null pointer to the structure. msg is set to null if
383 there is no error message. inflateInit does not perform any decompression
384 apart from possibly reading the zlib header if present: actual decompression
385 will be done by inflate(). (So next_in and avail_in may be modified, but
386 next_out and avail_out are unused and unchanged.) The current implementation
387 of inflateInit() does not process any header information -- that is deferred
388 until inflate() is called.
389 */
390
391
392 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
393 /*
394 inflate decompresses as much data as possible, and stops when the input
395 buffer becomes empty or the output buffer becomes full. It may introduce
396 some output latency (reading input without producing any output) except when
397 forced to flush.
398
399 The detailed semantics are as follows. inflate performs one or both of the
400 following actions:
401
402 - Decompress more input starting at next_in and update next_in and avail_in
403 accordingly. If not all input can be processed (because there is not
404 enough room in the output buffer), next_in is updated and processing will
405 resume at this point for the next call of inflate().
406
407 - Provide more output starting at next_out and update next_out and avail_out
408 accordingly. inflate() provides as much output as possible, until there is
409 no more input data or no more space in the output buffer (see below about
410 the flush parameter).
411
412 Before the call of inflate(), the application should ensure that at least
413 one of the actions is possible, by providing more input and/or consuming more
414 output, and updating the next_* and avail_* values accordingly. The
415 application can consume the uncompressed output when it wants, for example
416 when the output buffer is full (avail_out == 0), or after each call of
417 inflate(). If inflate returns Z_OK and with zero avail_out, it must be
418 called again after making room in the output buffer because there might be
419 more output pending.
420
421 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
422 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
423 output as possible to the output buffer. Z_BLOCK requests that inflate()
424 stop if and when it gets to the next deflate block boundary. When decoding
425 the zlib or gzip format, this will cause inflate() to return immediately
426 after the header and before the first block. When doing a raw inflate,
427 inflate() will go ahead and process the first block, and will return when it
428 gets to the end of that block, or when it runs out of data.
429
430 The Z_BLOCK option assists in appending to or combining deflate streams.
431 Also to assist in this, on return inflate() will set strm->data_type to the
432 number of unused bits in the last byte taken from strm->next_in, plus 64 if
433 inflate() is currently decoding the last block in the deflate stream, plus
434 128 if inflate() returned immediately after decoding an end-of-block code or
435 decoding the complete header up to just before the first byte of the deflate
436 stream. The end-of-block will not be indicated until all of the uncompressed
437 data from that block has been written to strm->next_out. The number of
438 unused bits may in general be greater than seven, except when bit 7 of
439 data_type is set, in which case the number of unused bits will be less than
440 eight. data_type is set as noted here every time inflate() returns for all
441 flush options, and so can be used to determine the amount of currently
442 consumed input in bits.
443
444 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
445 end of each deflate block header is reached, before any actual data in that
446 block is decoded. This allows the caller to determine the length of the
447 deflate block header for later use in random access within a deflate block.
448 256 is added to the value of strm->data_type when inflate() returns
449 immediately after reaching the end of the deflate block header.
450
451 inflate() should normally be called until it returns Z_STREAM_END or an
452 error. However if all decompression is to be performed in a single step (a
453 single call of inflate), the parameter flush should be set to Z_FINISH. In
454 this case all pending input is processed and all pending output is flushed;
455 avail_out must be large enough to hold all of the uncompressed data for the
456 operation to complete. (The size of the uncompressed data may have been
457 saved by the compressor for this purpose.) The use of Z_FINISH is not
458 required to perform an inflation in one step. However it may be used to
459 inform inflate that a faster approach can be used for the single inflate()
460 call. Z_FINISH also informs inflate to not maintain a sliding window if the
461 stream completes, which reduces inflate's memory footprint. If the stream
462 does not complete, either because not all of the stream is provided or not
463 enough output space is provided, then a sliding window will be allocated and
464 inflate() can be called again to continue the operation as if Z_NO_FLUSH had
465 been used.
466
467 In this implementation, inflate() always flushes as much output as
468 possible to the output buffer, and always uses the faster approach on the
469 first call. So the effects of the flush parameter in this implementation are
470 on the return value of inflate() as noted below, when inflate() returns early
471 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
472 memory for a sliding window when Z_FINISH is used.
473
474 If a preset dictionary is needed after this call (see inflateSetDictionary
475 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
476 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
477 strm->adler to the Adler-32 checksum of all output produced so far (that is,
478 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
479 below. At the end of the stream, inflate() checks that its computed adler32
480 checksum is equal to that saved by the compressor and returns Z_STREAM_END
481 only if the checksum is correct.
482
483 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
484 deflate data. The header type is detected automatically, if requested when
485 initializing with inflateInit2(). Any information contained in the gzip
486 header is not retained, so applications that need that information should
487 instead use raw inflate, see inflateInit2() below, or inflateBack() and
488 perform their own processing of the gzip header and trailer. When processing
489 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
490 producted so far. The CRC-32 is checked against the gzip trailer.
491
492 inflate() returns Z_OK if some progress has been made (more input processed
493 or more output produced), Z_STREAM_END if the end of the compressed data has
494 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
495 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
496 corrupted (input stream not conforming to the zlib format or incorrect check
497 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
498 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
499 Z_BUF_ERROR if no progress is possible or if there was not enough room in the
500 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
501 inflate() can be called again with more input and more output space to
502 continue decompressing. If Z_DATA_ERROR is returned, the application may
503 then call inflateSync() to look for a good compression block if a partial
504 recovery of the data is desired.
505 */
506
507
508 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
509 /*
510 All dynamically allocated data structures for this stream are freed.
511 This function discards any unprocessed input and does not flush any pending
512 output.
513
514 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
515 was inconsistent. In the error case, msg may be set but then points to a
516 static string (which must not be deallocated).
517 */
518
519
520 /* Advanced functions */
521
522 /*
523 The following functions are needed only in some special applications.
524 */
525
526 /*
527 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
528 int level,
529 int method,
530 int windowBits,
531 int memLevel,
532 int strategy));
533
534 This is another version of deflateInit with more compression options. The
535 fields next_in, zalloc, zfree and opaque must be initialized before by the
536 caller.
537
538 The method parameter is the compression method. It must be Z_DEFLATED in
539 this version of the library.
540
541 The windowBits parameter is the base two logarithm of the window size
542 (the size of the history buffer). It should be in the range 8..15 for this
543 version of the library. Larger values of this parameter result in better
544 compression at the expense of memory usage. The default value is 15 if
545 deflateInit is used instead.
546
547 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
548 determines the window size. deflate() will then generate raw deflate data
549 with no zlib header or trailer, and will not compute an adler32 check value.
550
551 windowBits can also be greater than 15 for optional gzip encoding. Add
552 16 to windowBits to write a simple gzip header and trailer around the
553 compressed data instead of a zlib wrapper. The gzip header will have no
554 file name, no extra data, no comment, no modification time (set to zero), no
555 header crc, and the operating system will be set to 255 (unknown). If a
556 gzip stream is being written, strm->adler is a crc32 instead of an adler32.
557
558 The memLevel parameter specifies how much memory should be allocated
559 for the internal compression state. memLevel=1 uses minimum memory but is
560 slow and reduces compression ratio; memLevel=9 uses maximum memory for
561 optimal speed. The default value is 8. See zconf.h for total memory usage
562 as a function of windowBits and memLevel.
563
564 The strategy parameter is used to tune the compression algorithm. Use the
565 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
566 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
567 string match), or Z_RLE to limit match distances to one (run-length
568 encoding). Filtered data consists mostly of small values with a somewhat
569 random distribution. In this case, the compression algorithm is tuned to
570 compress them better. The effect of Z_FILTERED is to force more Huffman
571 coding and less string matching; it is somewhat intermediate between
572 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
573 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
574 strategy parameter only affects the compression ratio but not the
575 correctness of the compressed output even if it is not set appropriately.
576 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
577 decoder for special applications.
578
579 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
580 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
581 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
582 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
583 set to null if there is no error message. deflateInit2 does not perform any
584 compression: this will be done by deflate().
585 */
586
587 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
588 const Bytef *dictionary,
589 uInt dictLength));
590 /*
591 Initializes the compression dictionary from the given byte sequence
592 without producing any compressed output. When using the zlib format, this
593 function must be called immediately after deflateInit, deflateInit2 or
594 deflateReset, and before any call of deflate. When doing raw deflate, this
595 function must be called either before any call of deflate, or immediately
596 after the completion of a deflate block, i.e. after all input has been
597 consumed and all output has been delivered when using any of the flush
598 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
599 compressor and decompressor must use exactly the same dictionary (see
600 inflateSetDictionary).
601
602 The dictionary should consist of strings (byte sequences) that are likely
603 to be encountered later in the data to be compressed, with the most commonly
604 used strings preferably put towards the end of the dictionary. Using a
605 dictionary is most useful when the data to be compressed is short and can be
606 predicted with good accuracy; the data can then be compressed better than
607 with the default empty dictionary.
608
609 Depending on the size of the compression data structures selected by
610 deflateInit or deflateInit2, a part of the dictionary may in effect be
611 discarded, for example if the dictionary is larger than the window size
612 provided in deflateInit or deflateInit2. Thus the strings most likely to be
613 useful should be put at the end of the dictionary, not at the front. In
614 addition, the current implementation of deflate will use at most the window
615 size minus 262 bytes of the provided dictionary.
616
617 Upon return of this function, strm->adler is set to the adler32 value
618 of the dictionary; the decompressor may later use this value to determine
619 which dictionary has been used by the compressor. (The adler32 value
620 applies to the whole dictionary even if only a subset of the dictionary is
621 actually used by the compressor.) If a raw deflate was requested, then the
622 adler32 value is not computed and strm->adler is not set.
623
624 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
625 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
626 inconsistent (for example if deflate has already been called for this stream
627 or if not at a block boundary for raw deflate). deflateSetDictionary does
628 not perform any compression: this will be done by deflate().
629 */
630
631 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
632 z_streamp source));
633 /*
634 Sets the destination stream as a complete copy of the source stream.
635
636 This function can be useful when several compression strategies will be
637 tried, for example when there are several ways of pre-processing the input
638 data with a filter. The streams that will be discarded should then be freed
639 by calling deflateEnd. Note that deflateCopy duplicates the internal
640 compression state which can be quite large, so this strategy is slow and can
641 consume lots of memory.
642
643 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
644 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
645 (such as zalloc being Z_NULL). msg is left unchanged in both source and
646 destination.
647 */
648
649 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
650 /*
651 This function is equivalent to deflateEnd followed by deflateInit,
652 but does not free and reallocate all the internal compression state. The
653 stream will keep the same compression level and any other attributes that
654 may have been set by deflateInit2.
655
656 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
657 stream state was inconsistent (such as zalloc or state being Z_NULL).
658 */
659
660 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
661 int level,
662 int strategy));
663 /*
664 Dynamically update the compression level and compression strategy. The
665 interpretation of level and strategy is as in deflateInit2. This can be
666 used to switch between compression and straight copy of the input data, or
667 to switch to a different kind of input data requiring a different strategy.
668 If the compression level is changed, the input available so far is
669 compressed with the old level (and may be flushed); the new level will take
670 effect only at the next call of deflate().
671
672 Before the call of deflateParams, the stream state must be set as for
673 a call of deflate(), since the currently available input may have to be
674 compressed and flushed. In particular, strm->avail_out must be non-zero.
675
676 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
677 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
678 strm->avail_out was zero.
679 */
680
681 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
682 int good_length,
683 int max_lazy,
684 int nice_length,
685 int max_chain));
686 /*
687 Fine tune deflate's internal compression parameters. This should only be
688 used by someone who understands the algorithm used by zlib's deflate for
689 searching for the best matching string, and even then only by the most
690 fanatic optimizer trying to squeeze out the last compressed bit for their
691 specific input data. Read the deflate.c source code for the meaning of the
692 max_lazy, good_length, nice_length, and max_chain parameters.
693
694 deflateTune() can be called after deflateInit() or deflateInit2(), and
695 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
696 */
697
698 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
699 uLong sourceLen));
700 /*
701 deflateBound() returns an upper bound on the compressed size after
702 deflation of sourceLen bytes. It must be called after deflateInit() or
703 deflateInit2(), and after deflateSetHeader(), if used. This would be used
704 to allocate an output buffer for deflation in a single pass, and so would be
705 called before deflate(). If that first deflate() call is provided the
706 sourceLen input bytes, an output buffer allocated to the size returned by
707 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
708 to return Z_STREAM_END. Note that it is possible for the compressed size to
709 be larger than the value returned by deflateBound() if flush options other
710 than Z_FINISH or Z_NO_FLUSH are used.
711 */
712
713 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
714 unsigned *pending,
715 int *bits));
716 /*
717 deflatePending() returns the number of bytes and bits of output that have
718 been generated, but not yet provided in the available output. The bytes not
719 provided would be due to the available output space having being consumed.
720 The number of bits of output not provided are between 0 and 7, where they
721 await more bits to join them in order to fill out a full byte. If pending
722 or bits are Z_NULL, then those values are not set.
723
724 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
725 stream state was inconsistent.
726 */
727
728 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
729 int bits,
730 int value));
731 /*
732 deflatePrime() inserts bits in the deflate output stream. The intent
733 is that this function is used to start off the deflate output with the bits
734 leftover from a previous deflate stream when appending to it. As such, this
735 function can only be used for raw deflate, and must be used before the first
736 deflate() call after a deflateInit2() or deflateReset(). bits must be less
737 than or equal to 16, and that many of the least significant bits of value
738 will be inserted in the output.
739
740 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
741 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
742 source stream state was inconsistent.
743 */
744
745 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
746 gz_headerp head));
747 /*
748 deflateSetHeader() provides gzip header information for when a gzip
749 stream is requested by deflateInit2(). deflateSetHeader() may be called
750 after deflateInit2() or deflateReset() and before the first call of
751 deflate(). The text, time, os, extra field, name, and comment information
752 in the provided gz_header structure are written to the gzip header (xflag is
753 ignored -- the extra flags are set according to the compression level). The
754 caller must assure that, if not Z_NULL, name and comment are terminated with
755 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
756 available there. If hcrc is true, a gzip header crc is included. Note that
757 the current versions of the command-line version of gzip (up through version
758 1.3.x) do not support header crc's, and will report that it is a "multi-part
759 gzip file" and give up.
760
761 If deflateSetHeader is not used, the default gzip header has text false,
762 the time set to zero, and os set to 255, with no extra, name, or comment
763 fields. The gzip header is returned to the default state by deflateReset().
764
765 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
766 stream state was inconsistent.
767 */
768
769 /*
770 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
771 int windowBits));
772
773 This is another version of inflateInit with an extra parameter. The
774 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
775 before by the caller.
776
777 The windowBits parameter is the base two logarithm of the maximum window
778 size (the size of the history buffer). It should be in the range 8..15 for
779 this version of the library. The default value is 15 if inflateInit is used
780 instead. windowBits must be greater than or equal to the windowBits value
781 provided to deflateInit2() while compressing, or it must be equal to 15 if
782 deflateInit2() was not used. If a compressed stream with a larger window
783 size is given as input, inflate() will return with the error code
784 Z_DATA_ERROR instead of trying to allocate a larger window.
785
786 windowBits can also be zero to request that inflate use the window size in
787 the zlib header of the compressed stream.
788
789 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
790 determines the window size. inflate() will then process raw deflate data,
791 not looking for a zlib or gzip header, not generating a check value, and not
792 looking for any check values for comparison at the end of the stream. This
793 is for use with other formats that use the deflate compressed data format
794 such as zip. Those formats provide their own check values. If a custom
795 format is developed using the raw deflate format for compressed data, it is
796 recommended that a check value such as an adler32 or a crc32 be applied to
797 the uncompressed data as is done in the zlib, gzip, and zip formats. For
798 most applications, the zlib format should be used as is. Note that comments
799 above on the use in deflateInit2() applies to the magnitude of windowBits.
800
801 windowBits can also be greater than 15 for optional gzip decoding. Add
802 32 to windowBits to enable zlib and gzip decoding with automatic header
803 detection, or add 16 to decode only the gzip format (the zlib format will
804 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
805 crc32 instead of an adler32.
806
807 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
808 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
809 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
810 invalid, such as a null pointer to the structure. msg is set to null if
811 there is no error message. inflateInit2 does not perform any decompression
812 apart from possibly reading the zlib header if present: actual decompression
813 will be done by inflate(). (So next_in and avail_in may be modified, but
814 next_out and avail_out are unused and unchanged.) The current implementation
815 of inflateInit2() does not process any header information -- that is
816 deferred until inflate() is called.
817 */
818
819 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
820 const Bytef *dictionary,
821 uInt dictLength));
822 /*
823 Initializes the decompression dictionary from the given uncompressed byte
824 sequence. This function must be called immediately after a call of inflate,
825 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
826 can be determined from the adler32 value returned by that call of inflate.
827 The compressor and decompressor must use exactly the same dictionary (see
828 deflateSetDictionary). For raw inflate, this function can be called at any
829 time to set the dictionary. If the provided dictionary is smaller than the
830 window and there is already data in the window, then the provided dictionary
831 will amend what's there. The application must insure that the dictionary
832 that was used for compression is provided.
833
834 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
835 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
836 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
837 expected one (incorrect adler32 value). inflateSetDictionary does not
838 perform any decompression: this will be done by subsequent calls of
839 inflate().
840 */
841
842 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
843 Bytef *dictionary,
844 uInt *dictLength));
845 /*
846 Returns the sliding dictionary being maintained by inflate. dictLength is
847 set to the number of bytes in the dictionary, and that many bytes are copied
848 to dictionary. dictionary must have enough space, where 32768 bytes is
849 always enough. If inflateGetDictionary() is called with dictionary equal to
850 Z_NULL, then only the dictionary length is returned, and nothing is copied.
851 Similary, if dictLength is Z_NULL, then it is not set.
852
853 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
854 stream state is inconsistent.
855 */
856
857 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
858 /*
859 Skips invalid compressed data until a possible full flush point (see above
860 for the description of deflate with Z_FULL_FLUSH) can be found, or until all
861 available input is skipped. No output is provided.
862
863 inflateSync searches for a 00 00 FF FF pattern in the compressed data.
864 All full flush points have this pattern, but not all occurrences of this
865 pattern are full flush points.
866
867 inflateSync returns Z_OK if a possible full flush point has been found,
868 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
869 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
870 In the success case, the application may save the current current value of
871 total_in which indicates where valid compressed data was found. In the
872 error case, the application may repeatedly call inflateSync, providing more
873 input each time, until success or end of the input data.
874 */
875
876 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
877 z_streamp source));
878 /*
879 Sets the destination stream as a complete copy of the source stream.
880
881 This function can be useful when randomly accessing a large stream. The
882 first pass through the stream can periodically record the inflate state,
883 allowing restarting inflate at those points when randomly accessing the
884 stream.
885
886 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
887 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
888 (such as zalloc being Z_NULL). msg is left unchanged in both source and
889 destination.
890 */
891
892 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
893 /*
894 This function is equivalent to inflateEnd followed by inflateInit,
895 but does not free and reallocate all the internal decompression state. The
896 stream will keep attributes that may have been set by inflateInit2.
897
898 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
899 stream state was inconsistent (such as zalloc or state being Z_NULL).
900 */
901
902 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
903 int windowBits));
904 /*
905 This function is the same as inflateReset, but it also permits changing
906 the wrap and window size requests. The windowBits parameter is interpreted
907 the same as it is for inflateInit2.
908
909 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
910 stream state was inconsistent (such as zalloc or state being Z_NULL), or if
911 the windowBits parameter is invalid.
912 */
913
914 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
915 int bits,
916 int value));
917 /*
918 This function inserts bits in the inflate input stream. The intent is
919 that this function is used to start inflating at a bit position in the
920 middle of a byte. The provided bits will be used before any bytes are used
921 from next_in. This function should only be used with raw inflate, and
922 should be used before the first inflate() call after inflateInit2() or
923 inflateReset(). bits must be less than or equal to 16, and that many of the
924 least significant bits of value will be inserted in the input.
925
926 If bits is negative, then the input stream bit buffer is emptied. Then
927 inflatePrime() can be called again to put bits in the buffer. This is used
928 to clear out bits leftover after feeding inflate a block description prior
929 to feeding inflate codes.
930
931 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
932 stream state was inconsistent.
933 */
934
935 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
936 /*
937 This function returns two values, one in the lower 16 bits of the return
938 value, and the other in the remaining upper bits, obtained by shifting the
939 return value down 16 bits. If the upper value is -1 and the lower value is
940 zero, then inflate() is currently decoding information outside of a block.
941 If the upper value is -1 and the lower value is non-zero, then inflate is in
942 the middle of a stored block, with the lower value equaling the number of
943 bytes from the input remaining to copy. If the upper value is not -1, then
944 it is the number of bits back from the current bit position in the input of
945 the code (literal or length/distance pair) currently being processed. In
946 that case the lower value is the number of bytes already emitted for that
947 code.
948
949 A code is being processed if inflate is waiting for more input to complete
950 decoding of the code, or if it has completed decoding but is waiting for
951 more output space to write the literal or match data.
952
953 inflateMark() is used to mark locations in the input data for random
954 access, which may be at bit positions, and to note those cases where the
955 output of a code may span boundaries of random access blocks. The current
956 location in the input stream can be determined from avail_in and data_type
957 as noted in the description for the Z_BLOCK flush parameter for inflate.
958
959 inflateMark returns the value noted above or -1 << 16 if the provided
960 source stream state was inconsistent.
961 */
962
963 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
964 gz_headerp head));
965 /*
966 inflateGetHeader() requests that gzip header information be stored in the
967 provided gz_header structure. inflateGetHeader() may be called after
968 inflateInit2() or inflateReset(), and before the first call of inflate().
969 As inflate() processes the gzip stream, head->done is zero until the header
970 is completed, at which time head->done is set to one. If a zlib stream is
971 being decoded, then head->done is set to -1 to indicate that there will be
972 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
973 used to force inflate() to return immediately after header processing is
974 complete and before any actual data is decompressed.
975
976 The text, time, xflags, and os fields are filled in with the gzip header
977 contents. hcrc is set to true if there is a header CRC. (The header CRC
978 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
979 contains the maximum number of bytes to write to extra. Once done is true,
980 extra_len contains the actual extra field length, and extra contains the
981 extra field, or that field truncated if extra_max is less than extra_len.
982 If name is not Z_NULL, then up to name_max characters are written there,
983 terminated with a zero unless the length is greater than name_max. If
984 comment is not Z_NULL, then up to comm_max characters are written there,
985 terminated with a zero unless the length is greater than comm_max. When any
986 of extra, name, or comment are not Z_NULL and the respective field is not
987 present in the header, then that field is set to Z_NULL to signal its
988 absence. This allows the use of deflateSetHeader() with the returned
989 structure to duplicate the header. However if those fields are set to
990 allocated memory, then the application will need to save those pointers
991 elsewhere so that they can be eventually freed.
992
993 If inflateGetHeader is not used, then the header information is simply
994 discarded. The header is always checked for validity, including the header
995 CRC if present. inflateReset() will reset the process to discard the header
996 information. The application would need to call inflateGetHeader() again to
997 retrieve the header from the next gzip stream.
998
999 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1000 stream state was inconsistent.
1001 */
1002
1003 /*
1004 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1005 unsigned char FAR *window));
1006
1007 Initialize the internal stream state for decompression using inflateBack()
1008 calls. The fields zalloc, zfree and opaque in strm must be initialized
1009 before the call. If zalloc and zfree are Z_NULL, then the default library-
1010 derived memory allocation routines are used. windowBits is the base two
1011 logarithm of the window size, in the range 8..15. window is a caller
1012 supplied buffer of that size. Except for special applications where it is
1013 assured that deflate was used with small window sizes, windowBits must be 15
1014 and a 32K byte window must be supplied to be able to decompress general
1015 deflate streams.
1016
1017 See inflateBack() for the usage of these routines.
1018
1019 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1020 the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1021 allocated, or Z_VERSION_ERROR if the version of the library does not match
1022 the version of the header file.
1023 */
1024
1025 typedef unsigned (*in_func) OF((void FAR *,
1026 z_const unsigned char FAR * FAR *));
1027 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1028
1029 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1030 in_func in, void FAR *in_desc,
1031 out_func out, void FAR *out_desc));
1032 /*
1033 inflateBack() does a raw inflate with a single call using a call-back
1034 interface for input and output. This is potentially more efficient than
1035 inflate() for file i/o applications, in that it avoids copying between the
1036 output and the sliding window by simply making the window itself the output
1037 buffer. inflate() can be faster on modern CPUs when used with large
1038 buffers. inflateBack() trusts the application to not change the output
1039 buffer passed by the output function, at least until inflateBack() returns.
1040
1041 inflateBackInit() must be called first to allocate the internal state
1042 and to initialize the state with the user-provided window buffer.
1043 inflateBack() may then be used multiple times to inflate a complete, raw
1044 deflate stream with each call. inflateBackEnd() is then called to free the
1045 allocated state.
1046
1047 A raw deflate stream is one with no zlib or gzip header or trailer.
1048 This routine would normally be used in a utility that reads zip or gzip
1049 files and writes out uncompressed files. The utility would decode the
1050 header and process the trailer on its own, hence this routine expects only
1051 the raw deflate stream to decompress. This is different from the normal
1052 behavior of inflate(), which expects either a zlib or gzip header and
1053 trailer around the deflate stream.
1054
1055 inflateBack() uses two subroutines supplied by the caller that are then
1056 called by inflateBack() for input and output. inflateBack() calls those
1057 routines until it reads a complete deflate stream and writes out all of the
1058 uncompressed data, or until it encounters an error. The function's
1059 parameters and return types are defined above in the in_func and out_func
1060 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1061 number of bytes of provided input, and a pointer to that input in buf. If
1062 there is no input available, in() must return zero--buf is ignored in that
1063 case--and inflateBack() will return a buffer error. inflateBack() will call
1064 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
1065 should return zero on success, or non-zero on failure. If out() returns
1066 non-zero, inflateBack() will return with an error. Neither in() nor out()
1067 are permitted to change the contents of the window provided to
1068 inflateBackInit(), which is also the buffer that out() uses to write from.
1069 The length written by out() will be at most the window size. Any non-zero
1070 amount of input may be provided by in().
1071
1072 For convenience, inflateBack() can be provided input on the first call by
1073 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1074 in() will be called. Therefore strm->next_in must be initialized before
1075 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1076 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1077 must also be initialized, and then if strm->avail_in is not zero, input will
1078 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1079
1080 The in_desc and out_desc parameters of inflateBack() is passed as the
1081 first parameter of in() and out() respectively when they are called. These
1082 descriptors can be optionally used to pass any information that the caller-
1083 supplied in() and out() functions need to do their job.
1084
1085 On return, inflateBack() will set strm->next_in and strm->avail_in to
1086 pass back any unused input that was provided by the last in() call. The
1087 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1088 if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1089 in the deflate stream (in which case strm->msg is set to indicate the nature
1090 of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1091 In the case of Z_BUF_ERROR, an input or output error can be distinguished
1092 using strm->next_in which will be Z_NULL only if in() returned an error. If
1093 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1094 non-zero. (in() will always be called before out(), so strm->next_in is
1095 assured to be defined if out() returns non-zero.) Note that inflateBack()
1096 cannot return Z_OK.
1097 */
1098
1099 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1100 /*
1101 All memory allocated by inflateBackInit() is freed.
1102
1103 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1104 state was inconsistent.
1105 */
1106
1107 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1108 /* Return flags indicating compile-time options.
1109
1110 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1111 1.0: size of uInt
1112 3.2: size of uLong
1113 5.4: size of voidpf (pointer)
1114 7.6: size of z_off_t
1115
1116 Compiler, assembler, and debug options:
1117 8: DEBUG
1118 9: ASMV or ASMINF -- use ASM code
1119 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1120 11: 0 (reserved)
1121
1122 One-time table building (smaller code, but not thread-safe if true):
1123 12: BUILDFIXED -- build static block decoding tables when needed
1124 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1125 14,15: 0 (reserved)
1126
1127 Library content (indicates missing functionality):
1128 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1129 deflate code when not needed)
1130 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1131 and decode gzip streams (to avoid linking crc code)
1132 18-19: 0 (reserved)
1133
1134 Operation variations (changes in library functionality):
1135 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1136 21: FASTEST -- deflate algorithm with only one, lowest compression level
1137 22,23: 0 (reserved)
1138
1139 The sprintf variant used by gzprintf (zero is best):
1140 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1141 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1142 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1143
1144 Remainder:
1145 27-31: 0 (reserved)
1146 */
1147
1148 #ifndef Z_SOLO
1149
1150 /* utility functions */
1151
1152 /*
1153 The following utility functions are implemented on top of the basic
1154 stream-oriented functions. To simplify the interface, some default options
1155 are assumed (compression level and memory usage, standard memory allocation
1156 functions). The source code of these utility functions can be modified if
1157 you need special options.
1158 */
1159
1160 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1161 const Bytef *source, uLong sourceLen));
1162 /*
1163 Compresses the source buffer into the destination buffer. sourceLen is
1164 the byte length of the source buffer. Upon entry, destLen is the total size
1165 of the destination buffer, which must be at least the value returned by
1166 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1167 compressed buffer.
1168
1169 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1170 enough memory, Z_BUF_ERROR if there was not enough room in the output
1171 buffer.
1172 */
1173
1174 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1175 const Bytef *source, uLong sourceLen,
1176 int level));
1177 /*
1178 Compresses the source buffer into the destination buffer. The level
1179 parameter has the same meaning as in deflateInit. sourceLen is the byte
1180 length of the source buffer. Upon entry, destLen is the total size of the
1181 destination buffer, which must be at least the value returned by
1182 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1183 compressed buffer.
1184
1185 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1186 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1187 Z_STREAM_ERROR if the level parameter is invalid.
1188 */
1189
1190 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1191 /*
1192 compressBound() returns an upper bound on the compressed size after
1193 compress() or compress2() on sourceLen bytes. It would be used before a
1194 compress() or compress2() call to allocate the destination buffer.
1195 */
1196
1197 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1198 const Bytef *source, uLong sourceLen));
1199 /*
1200 Decompresses the source buffer into the destination buffer. sourceLen is
1201 the byte length of the source buffer. Upon entry, destLen is the total size
1202 of the destination buffer, which must be large enough to hold the entire
1203 uncompressed data. (The size of the uncompressed data must have been saved
1204 previously by the compressor and transmitted to the decompressor by some
1205 mechanism outside the scope of this compression library.) Upon exit, destLen
1206 is the actual size of the uncompressed buffer.
1207
1208 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1209 enough memory, Z_BUF_ERROR if there was not enough room in the output
1210 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1211 the case where there is not enough room, uncompress() will fill the output
1212 buffer with the uncompressed data up to that point.
1213 */
1214
1215 /* gzip file access functions */
1216
1217 /*
1218 This library supports reading and writing files in gzip (.gz) format with
1219 an interface similar to that of stdio, using the functions that start with
1220 "gz". The gzip format is different from the zlib format. gzip is a gzip
1221 wrapper, documented in RFC 1952, wrapped around a deflate stream.
1222 */
1223
1224 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1225
1226 /*
1227 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1228
1229 Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1230 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1231 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1232 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1233 for fixed code compression as in "wb9F". (See the description of
1234 deflateInit2 for more information about the strategy parameter.) 'T' will
1235 request transparent writing or appending with no compression and not using
1236 the gzip format.
1237
1238 "a" can be used instead of "w" to request that the gzip stream that will
1239 be written be appended to the file. "+" will result in an error, since
1240 reading and writing to the same gzip file is not supported. The addition of
1241 "x" when writing will create the file exclusively, which fails if the file
1242 already exists. On systems that support it, the addition of "e" when
1243 reading or writing will set the flag to close the file on an execve() call.
1244
1245 These functions, as well as gzip, will read and decode a sequence of gzip
1246 streams in a file. The append function of gzopen() can be used to create
1247 such a file. (Also see gzflush() for another way to do this.) When
1248 appending, gzopen does not test whether the file begins with a gzip stream,
1249 nor does it look for the end of the gzip streams to begin appending. gzopen
1250 will simply append a gzip stream to the existing file.
1251
1252 gzopen can be used to read a file which is not in gzip format; in this
1253 case gzread will directly read from the file without decompression. When
1254 reading, this will be detected automatically by looking for the magic two-
1255 byte gzip header.
1256
1257 gzopen returns NULL if the file could not be opened, if there was
1258 insufficient memory to allocate the gzFile state, or if an invalid mode was
1259 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1260 errno can be checked to determine if the reason gzopen failed was that the
1261 file could not be opened.
1262 */
1263
1264 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1265 /*
1266 gzdopen associates a gzFile with the file descriptor fd. File descriptors
1267 are obtained from calls like open, dup, creat, pipe or fileno (if the file
1268 has been previously opened with fopen). The mode parameter is as in gzopen.
1269
1270 The next call of gzclose on the returned gzFile will also close the file
1271 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1272 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1273 mode);. The duplicated descriptor should be saved to avoid a leak, since
1274 gzdopen does not close fd if it fails. If you are using fileno() to get the
1275 file descriptor from a FILE *, then you will have to use dup() to avoid
1276 double-close()ing the file descriptor. Both gzclose() and fclose() will
1277 close the associated file descriptor, so they need to have different file
1278 descriptors.
1279
1280 gzdopen returns NULL if there was insufficient memory to allocate the
1281 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1282 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1283 used until the next gz* read, write, seek, or close operation, so gzdopen
1284 will not detect if fd is invalid (unless fd is -1).
1285 */
1286
1287 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1288 /*
1289 Set the internal buffer size used by this library's functions. The
1290 default buffer size is 8192 bytes. This function must be called after
1291 gzopen() or gzdopen(), and before any other calls that read or write the
1292 file. The buffer memory allocation is always deferred to the first read or
1293 write. Two buffers are allocated, either both of the specified size when
1294 writing, or one of the specified size and the other twice that size when
1295 reading. A larger buffer size of, for example, 64K or 128K bytes will
1296 noticeably increase the speed of decompression (reading).
1297
1298 The new buffer size also affects the maximum length for gzprintf().
1299
1300 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1301 too late.
1302 */
1303
1304 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1305 /*
1306 Dynamically update the compression level or strategy. See the description
1307 of deflateInit2 for the meaning of these parameters.
1308
1309 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1310 opened for writing.
1311 */
1312
1313 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1314 /*
1315 Reads the given number of uncompressed bytes from the compressed file. If
1316 the input file is not in gzip format, gzread copies the given number of
1317 bytes into the buffer directly from the file.
1318
1319 After reaching the end of a gzip stream in the input, gzread will continue
1320 to read, looking for another gzip stream. Any number of gzip streams may be
1321 concatenated in the input file, and will all be decompressed by gzread().
1322 If something other than a gzip stream is encountered after a gzip stream,
1323 that remaining trailing garbage is ignored (and no error is returned).
1324
1325 gzread can be used to read a gzip file that is being concurrently written.
1326 Upon reaching the end of the input, gzread will return with the available
1327 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1328 gzclearerr can be used to clear the end of file indicator in order to permit
1329 gzread to be tried again. Z_OK indicates that a gzip stream was completed
1330 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1331 middle of a gzip stream. Note that gzread does not return -1 in the event
1332 of an incomplete gzip stream. This error is deferred until gzclose(), which
1333 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1334 stream. Alternatively, gzerror can be used before gzclose to detect this
1335 case.
1336
1337 gzread returns the number of uncompressed bytes actually read, less than
1338 len for end of file, or -1 for error.
1339 */
1340
1341 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1342 voidpc buf, unsigned len));
1343 /*
1344 Writes the given number of uncompressed bytes into the compressed file.
1345 gzwrite returns the number of uncompressed bytes written or 0 in case of
1346 error.
1347 */
1348
1349 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1350 /*
1351 Converts, formats, and writes the arguments to the compressed file under
1352 control of the format string, as in fprintf. gzprintf returns the number of
1353 uncompressed bytes actually written, or 0 in case of error. The number of
1354 uncompressed bytes written is limited to 8191, or one less than the buffer
1355 size given to gzbuffer(). The caller should assure that this limit is not
1356 exceeded. If it is exceeded, then gzprintf() will return an error (0) with
1357 nothing written. In this case, there may also be a buffer overflow with
1358 unpredictable consequences, which is possible only if zlib was compiled with
1359 the insecure functions sprintf() or vsprintf() because the secure snprintf()
1360 or vsnprintf() functions were not available. This can be determined using
1361 zlibCompileFlags().
1362 */
1363
1364 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1365 /*
1366 Writes the given null-terminated string to the compressed file, excluding
1367 the terminating null character.
1368
1369 gzputs returns the number of characters written, or -1 in case of error.
1370 */
1371
1372 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1373 /*
1374 Reads bytes from the compressed file until len-1 characters are read, or a
1375 newline character is read and transferred to buf, or an end-of-file
1376 condition is encountered. If any characters are read or if len == 1, the
1377 string is terminated with a null character. If no characters are read due
1378 to an end-of-file or len < 1, then the buffer is left untouched.
1379
1380 gzgets returns buf which is a null-terminated string, or it returns NULL
1381 for end-of-file or in case of error. If there was an error, the contents at
1382 buf are indeterminate.
1383 */
1384
1385 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1386 /*
1387 Writes c, converted to an unsigned char, into the compressed file. gzputc
1388 returns the value that was written, or -1 in case of error.
1389 */
1390
1391 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1392 /*
1393 Reads one byte from the compressed file. gzgetc returns this byte or -1
1394 in case of end of file or error. This is implemented as a macro for speed.
1395 As such, it does not do all of the checking the other functions do. I.e.
1396 it does not check to see if file is NULL, nor whether the structure file
1397 points to has been clobbered or not.
1398 */
1399
1400 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1401 /*
1402 Push one character back onto the stream to be read as the first character
1403 on the next read. At least one character of push-back is allowed.
1404 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1405 fail if c is -1, and may fail if a character has been pushed but not read
1406 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1407 output buffer size of pushed characters is allowed. (See gzbuffer above.)
1408 The pushed character will be discarded if the stream is repositioned with
1409 gzseek() or gzrewind().
1410 */
1411
1412 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1413 /*
1414 Flushes all pending output into the compressed file. The parameter flush
1415 is as in the deflate() function. The return value is the zlib error number
1416 (see function gzerror below). gzflush is only permitted when writing.
1417
1418 If the flush parameter is Z_FINISH, the remaining data is written and the
1419 gzip stream is completed in the output. If gzwrite() is called again, a new
1420 gzip stream will be started in the output. gzread() is able to read such
1421 concatented gzip streams.
1422
1423 gzflush should be called only when strictly necessary because it will
1424 degrade compression if called too often.
1425 */
1426
1427 /*
1428 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1429 z_off_t offset, int whence));
1430
1431 Sets the starting position for the next gzread or gzwrite on the given
1432 compressed file. The offset represents a number of bytes in the
1433 uncompressed data stream. The whence parameter is defined as in lseek(2);
1434 the value SEEK_END is not supported.
1435
1436 If the file is opened for reading, this function is emulated but can be
1437 extremely slow. If the file is opened for writing, only forward seeks are
1438 supported; gzseek then compresses a sequence of zeroes up to the new
1439 starting position.
1440
1441 gzseek returns the resulting offset location as measured in bytes from
1442 the beginning of the uncompressed stream, or -1 in case of error, in
1443 particular if the file is opened for writing and the new starting position
1444 would be before the current position.
1445 */
1446
1447 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1448 /*
1449 Rewinds the given file. This function is supported only for reading.
1450
1451 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1452 */
1453
1454 /*
1455 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1456
1457 Returns the starting position for the next gzread or gzwrite on the given
1458 compressed file. This position represents a number of bytes in the
1459 uncompressed data stream, and is zero when starting, even if appending or
1460 reading a gzip stream from the middle of a file using gzdopen().
1461
1462 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1463 */
1464
1465 /*
1466 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1467
1468 Returns the current offset in the file being read or written. This offset
1469 includes the count of bytes that precede the gzip stream, for example when
1470 appending or when using gzdopen() for reading. When reading, the offset
1471 does not include as yet unused buffered input. This information can be used
1472 for a progress indicator. On error, gzoffset() returns -1.
1473 */
1474
1475 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1476 /*
1477 Returns true (1) if the end-of-file indicator has been set while reading,
1478 false (0) otherwise. Note that the end-of-file indicator is set only if the
1479 read tried to go past the end of the input, but came up short. Therefore,
1480 just like feof(), gzeof() may return false even if there is no more data to
1481 read, in the event that the last read request was for the exact number of
1482 bytes remaining in the input file. This will happen if the input file size
1483 is an exact multiple of the buffer size.
1484
1485 If gzeof() returns true, then the read functions will return no more data,
1486 unless the end-of-file indicator is reset by gzclearerr() and the input file
1487 has grown since the previous end of file was detected.
1488 */
1489
1490 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1491 /*
1492 Returns true (1) if file is being copied directly while reading, or false
1493 (0) if file is a gzip stream being decompressed.
1494
1495 If the input file is empty, gzdirect() will return true, since the input
1496 does not contain a gzip stream.
1497
1498 If gzdirect() is used immediately after gzopen() or gzdopen() it will
1499 cause buffers to be allocated to allow reading the file to determine if it
1500 is a gzip file. Therefore if gzbuffer() is used, it should be called before
1501 gzdirect().
1502
1503 When writing, gzdirect() returns true (1) if transparent writing was
1504 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1505 gzdirect() is not needed when writing. Transparent writing must be
1506 explicitly requested, so the application already knows the answer. When
1507 linking statically, using gzdirect() will include all of the zlib code for
1508 gzip file reading and decompression, which may not be desired.)
1509 */
1510
1511 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1512 /*
1513 Flushes all pending output if necessary, closes the compressed file and
1514 deallocates the (de)compression state. Note that once file is closed, you
1515 cannot call gzerror with file, since its structures have been deallocated.
1516 gzclose must not be called more than once on the same file, just as free
1517 must not be called more than once on the same allocation.
1518
1519 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1520 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1521 last read ended in the middle of a gzip stream, or Z_OK on success.
1522 */
1523
1524 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1525 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1526 /*
1527 Same as gzclose(), but gzclose_r() is only for use when reading, and
1528 gzclose_w() is only for use when writing or appending. The advantage to
1529 using these instead of gzclose() is that they avoid linking in zlib
1530 compression or decompression code that is not used when only reading or only
1531 writing respectively. If gzclose() is used, then both compression and
1532 decompression code will be included the application when linking to a static
1533 zlib library.
1534 */
1535
1536 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1537 /*
1538 Returns the error message for the last error which occurred on the given
1539 compressed file. errnum is set to zlib error number. If an error occurred
1540 in the file system and not in the compression library, errnum is set to
1541 Z_ERRNO and the application may consult errno to get the exact error code.
1542
1543 The application must not modify the returned string. Future calls to
1544 this function may invalidate the previously returned string. If file is
1545 closed, then the string previously returned by gzerror will no longer be
1546 available.
1547
1548 gzerror() should be used to distinguish errors from end-of-file for those
1549 functions above that do not distinguish those cases in their return values.
1550 */
1551
1552 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1553 /*
1554 Clears the error and end-of-file flags for file. This is analogous to the
1555 clearerr() function in stdio. This is useful for continuing to read a gzip
1556 file that is being written concurrently.
1557 */
1558
1559 #endif /* !Z_SOLO */
1560
1561 /* checksum functions */
1562
1563 /*
1564 These functions are not related to compression but are exported
1565 anyway because they might be useful in applications using the compression
1566 library.
1567 */
1568
1569 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1570 /*
1571 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1572 return the updated checksum. If buf is Z_NULL, this function returns the
1573 required initial value for the checksum.
1574
1575 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1576 much faster.
1577
1578 Usage example:
1579
1580 uLong adler = adler32(0L, Z_NULL, 0);
1581
1582 while (read_buffer(buffer, length) != EOF) {
1583 adler = adler32(adler, buffer, length);
1584 }
1585 if (adler != original_adler) error();
1586 */
1587
1588 /*
1589 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1590 z_off_t len2));
1591
1592 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1593 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1594 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1595 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1596 that the z_off_t type (like off_t) is a signed integer. If len2 is
1597 negative, the result has no meaning or utility.
1598 */
1599
1600 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1601 /*
1602 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1603 updated CRC-32. If buf is Z_NULL, this function returns the required
1604 initial value for the crc. Pre- and post-conditioning (one's complement) is
1605 performed within this function so it shouldn't be done by the application.
1606
1607 Usage example:
1608
1609 uLong crc = crc32(0L, Z_NULL, 0);
1610
1611 while (read_buffer(buffer, length) != EOF) {
1612 crc = crc32(crc, buffer, length);
1613 }
1614 if (crc != original_crc) error();
1615 */
1616
1617 /*
1618 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1619
1620 Combine two CRC-32 check values into one. For two sequences of bytes,
1621 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1622 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1623 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1624 len2.
1625 */
1626
1627
1628 /* various hacks, don't look :) */
1629
1630 /* deflateInit and inflateInit are macros to allow checking the zlib version
1631 * and the compiler's view of z_stream:
1632 */
1633 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1634 const char *version, int stream_size));
1635 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1636 const char *version, int stream_size));
1637 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1638 int windowBits, int memLevel,
1639 int strategy, const char *version,
1640 int stream_size));
1641 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1642 const char *version, int stream_size));
1643 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1644 unsigned char FAR *window,
1645 const char *version,
1646 int stream_size));
1647 #define deflateInit(strm, level) \
1648 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1649 #define inflateInit(strm) \
1650 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1651 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1652 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1653 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1654 #define inflateInit2(strm, windowBits) \
1655 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1656 (int)sizeof(z_stream))
1657 #define inflateBackInit(strm, windowBits, window) \
1658 inflateBackInit_((strm), (windowBits), (window), \
1659 ZLIB_VERSION, (int)sizeof(z_stream))
1660
1661 #ifndef Z_SOLO
1662
1663 /* gzgetc() macro and its supporting function and exposed data structure. Note
1664 * that the real internal state is much larger than the exposed structure.
1665 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1666 * user should not mess with these exposed elements, since their names or
1667 * behavior could change in the future, perhaps even capriciously. They can
1668 * only be used by the gzgetc() macro. You have been warned.
1669 */
1670 struct gzFile_s {
1671 unsigned have;
1672 unsigned char *next;
1673 z_off64_t pos;
1674 };
1675 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
1676 #ifdef Z_PREFIX_SET
1677 # undef z_gzgetc
1678 # define z_gzgetc(g) \
1679 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1680 #else
1681 # define gzgetc(g) \
1682 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1683 #endif
1684
1685 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1686 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1687 * both are true, the application gets the *64 functions, and the regular
1688 * functions are changed to 64 bits) -- in case these are set on systems
1689 * without large file support, _LFS64_LARGEFILE must also be true
1690 */
1691 #ifdef Z_LARGE64
1692 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1693 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1694 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1695 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1696 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1697 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1698 #endif
1699
1700 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1701 # ifdef Z_PREFIX_SET
1702 # define z_gzopen z_gzopen64
1703 # define z_gzseek z_gzseek64
1704 # define z_gztell z_gztell64
1705 # define z_gzoffset z_gzoffset64
1706 # define z_adler32_combine z_adler32_combine64
1707 # define z_crc32_combine z_crc32_combine64
1708 # else
1709 # define gzopen gzopen64
1710 # define gzseek gzseek64
1711 # define gztell gztell64
1712 # define gzoffset gzoffset64
1713 # define adler32_combine adler32_combine64
1714 # define crc32_combine crc32_combine64
1715 # endif
1716 # ifndef Z_LARGE64
1717 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1718 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1719 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1720 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1721 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1722 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1723 # endif
1724 #else
1725 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1726 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1727 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1728 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1729 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1730 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1731 #endif
1732
1733 #else /* Z_SOLO */
1734
1735 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1736 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1737
1738 #endif /* !Z_SOLO */
1739
1740 /* hack for buggy compilers */
1741 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1742 struct internal_state {int dummy;};
1743 #endif
1744
1745 /* undocumented functions */
1746 ZEXTERN const char * ZEXPORT zError OF((int));
1747 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1748 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1749 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1750 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1751 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1752 #if defined(_WIN32) && !defined(Z_SOLO)
1753 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1754 const char *mode));
1755 #endif
1756 #if defined(STDC) || defined(Z_HAVE_STDARG_H)
1757 # ifndef Z_SOLO
1758 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1759 const char *format,
1760 va_list va));
1761 # endif
1762 #endif
1763
1764 #ifdef __cplusplus
1765 }
1766 #endif
1767
1768 #endif /* ZLIB_H */