1#ifndef ZLIB_H_
2#define ZLIB_H_
3/* zlib.h -- interface of the 'zlib-ng' compression library
4 Forked from and compatible with zlib 1.2.11
5
6 Copyright (C) 1995-2016 Jean-loup Gailly and Mark Adler
7
8 This software is provided 'as-is', without any express or implied
9 warranty. In no event will the authors be held liable for any damages
10 arising from the use of this software.
11
12 Permission is granted to anyone to use this software for any purpose,
13 including commercial applications, and to alter it and redistribute it
14 freely, subject to the following restrictions:
15
16 1. The origin of this software must not be misrepresented; you must not
17 claim that you wrote the original software. If you use this software
18 in a product, an acknowledgment in the product documentation would be
19 appreciated but is not required.
20 2. Altered source versions must be plainly marked as such, and must not be
21 misrepresented as being the original software.
22 3. This notice may not be removed or altered from any source distribution.
23
24 Jean-loup Gailly Mark Adler
25 jloup@gzip.org madler@alumni.caltech.edu
26
27
28 The data format used by the zlib library is described by RFCs (Request for
29 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
30 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
31*/
32
33#include <stdint.h>
34#include <stdarg.h>
35#include "zconf.h"
36
37#ifdef __cplusplus
38extern "C" {
39#endif
40
41#define ZLIBNG_VERSION "1.9.9"
42#define ZLIBNG_VERNUM 0x1990
43#define ZLIBNG_VER_MAJOR 1
44#define ZLIBNG_VER_MINOR 9
45#define ZLIBNG_VER_REVISION 9
46#define ZLIBNG_VER_SUBREVISION 0
47
48#define ZLIB_VERSION "1.2.11.zlib-ng"
49#define ZLIB_VERNUM 0x12bf
50#define ZLIB_VER_MAJOR 1
51#define ZLIB_VER_MINOR 2
52#define ZLIB_VER_REVISION 11
53#define ZLIB_VER_SUBREVISION 0
54
55/*
56 The 'zlib' compression library provides in-memory compression and
57 decompression functions, including integrity checks of the uncompressed data.
58 This version of the library supports only one compression method (deflation)
59 but other algorithms will be added later and will have the same stream
60 interface.
61
62 Compression can be done in a single step if the buffers are large enough,
63 or can be done by repeated calls of the compression function. In the latter
64 case, the application must provide more input and/or consume the output
65 (providing more output space) before each call.
66
67 The compressed data format used by default by the in-memory functions is
68 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
69 around a deflate stream, which is itself documented in RFC 1951.
70
71 The library also supports reading and writing files in gzip (.gz) format
72 with an interface similar to that of stdio using the functions that start
73 with "gz". The gzip format is different from the zlib format. gzip is a
74 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
75
76 This library can optionally read and write gzip and raw deflate streams in
77 memory as well.
78
79 The zlib format was designed to be compact and fast for use in memory
80 and on communications channels. The gzip format was designed for single-
81 file compression on file systems, has a larger header than zlib to maintain
82 directory information, and uses a different, slower check method than zlib.
83
84 The library does not install any signal handler. The decoder checks
85 the consistency of the compressed data, so the library should never crash
86 even in the case of corrupted input.
87*/
88
89typedef void *(*alloc_func) (void *opaque, unsigned int items, unsigned int size);
90typedef void (*free_func) (void *opaque, void *address);
91
92struct internal_state;
93
94typedef struct z_stream_s {
95 const unsigned char *next_in; /* next input byte */
96 uint32_t avail_in; /* number of bytes available at next_in */
97 size_t total_in; /* total number of input bytes read so far */
98
99 unsigned char *next_out; /* next output byte will go here */
100 uint32_t avail_out; /* remaining free space at next_out */
101 size_t total_out; /* total number of bytes output so far */
102
103 const char *msg; /* last error message, NULL if no error */
104 struct internal_state *state; /* not visible by applications */
105
106 alloc_func zalloc; /* used to allocate the internal state */
107 free_func zfree; /* used to free the internal state */
108 void *opaque; /* private data object passed to zalloc and zfree */
109
110 int data_type; /* best guess about the data type: binary or text
111 for deflate, or the decoding state for inflate */
112 unsigned long adler; /* Adler-32 or CRC-32 value of the uncompressed data */
113 unsigned long reserved; /* reserved for future use */
114} z_stream;
115
116typedef z_stream *z_streamp; /* Obsolete type, retained for compatibility only */
117
118/*
119 gzip header information passed to and from zlib routines. See RFC 1952
120 for more details on the meanings of these fields.
121*/
122typedef struct gz_header_s {
123 int text; /* true if compressed data believed to be text */
124 unsigned long time; /* modification time */
125 int xflags; /* extra flags (not used when writing a gzip file) */
126 int os; /* operating system */
127 unsigned char *extra; /* pointer to extra field or NULL if none */
128 unsigned int extra_len; /* extra field length (valid if extra != NULL) */
129 unsigned int extra_max; /* space at extra (only when reading header) */
130 unsigned char *name; /* pointer to zero-terminated file name or NULL */
131 unsigned int name_max; /* space at name (only when reading header) */
132 unsigned char *comment; /* pointer to zero-terminated comment or NULL */
133 unsigned int comm_max; /* space at comment (only when reading header) */
134 int hcrc; /* true if there was or will be a header crc */
135 int done; /* true when done reading gzip header (not used when writing a gzip file) */
136} gz_header;
137
138typedef gz_header *gz_headerp;
139
140/*
141 The application must update next_in and avail_in when avail_in has dropped
142 to zero. It must update next_out and avail_out when avail_out has dropped
143 to zero. The application must initialize zalloc, zfree and opaque before
144 calling the init function. All other fields are set by the compression
145 library and must not be updated by the application.
146
147 The opaque value provided by the application will be passed as the first
148 parameter for calls of zalloc and zfree. This can be useful for custom
149 memory management. The compression library attaches no meaning to the
150 opaque value.
151
152 zalloc must return NULL if there is not enough memory for the object.
153 If zlib is used in a multi-threaded application, zalloc and zfree must be
154 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
155 Z_NULL on entry to the initialization function, they are set to internal
156 routines that use the standard library functions malloc() and free().
157
158 The fields total_in and total_out can be used for statistics or progress
159 reports. After compression, total_in holds the total size of the
160 uncompressed data and may be saved for use by the decompressor (particularly
161 if the decompressor wants to decompress everything in a single step).
162*/
163
164 /* constants */
165
166#define Z_NO_FLUSH 0
167#define Z_PARTIAL_FLUSH 1
168#define Z_SYNC_FLUSH 2
169#define Z_FULL_FLUSH 3
170#define Z_FINISH 4
171#define Z_BLOCK 5
172#define Z_TREES 6
173/* Allowed flush values; see deflate() and inflate() below for details */
174
175#define Z_OK 0
176#define Z_STREAM_END 1
177#define Z_NEED_DICT 2
178#define Z_ERRNO (-1)
179#define Z_STREAM_ERROR (-2)
180#define Z_DATA_ERROR (-3)
181#define Z_MEM_ERROR (-4)
182#define Z_BUF_ERROR (-5)
183#define Z_VERSION_ERROR (-6)
184/* Return codes for the compression/decompression functions. Negative values
185 * are errors, positive values are used for special but normal events.
186 */
187
188#define Z_NO_COMPRESSION 0
189#define Z_BEST_SPEED 1
190#define Z_BEST_COMPRESSION 9
191#define Z_DEFAULT_COMPRESSION (-1)
192/* compression levels */
193
194#define Z_FILTERED 1
195#define Z_HUFFMAN_ONLY 2
196#define Z_RLE 3
197#define Z_FIXED 4
198#define Z_DEFAULT_STRATEGY 0
199/* compression strategy; see deflateInit2() below for details */
200
201#define Z_BINARY 0
202#define Z_TEXT 1
203#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
204#define Z_UNKNOWN 2
205/* Possible values of the data_type field for deflate() */
206
207#define Z_DEFLATED 8
208/* The deflate compression method (the only one supported in this version) */
209
210#define Z_NULL NULL /* for compatibility with zlib, was for initializing zalloc, zfree, opaque */
211
212#define zlib_version zlibVersion()
213/* for compatibility with versions < 1.0.2 */
214
215
216 /* basic functions */
217
218ZEXTERN const char * ZEXPORT zlibVersion(void);
219/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
220 If the first character differs, the library code actually used is not
221 compatible with the zlib.h header file used by the application. This check
222 is automatically made by deflateInit and inflateInit.
223 */
224
225/*
226ZEXTERN int ZEXPORT deflateInit (z_stream *strm, int level);
227
228 Initializes the internal stream state for compression. The fields
229 zalloc, zfree and opaque must be initialized before by the caller. If
230 zalloc and zfree are set to NULL, deflateInit updates them to use default
231 allocation functions.
232
233 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
234 1 gives best speed, 9 gives best compression, 0 gives no compression at all
235 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
236 requests a default compromise between speed and compression (currently
237 equivalent to level 6).
238
239 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
240 memory, Z_STREAM_ERROR if level is not a valid compression level, or
241 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
242 with the version assumed by the caller (ZLIB_VERSION). msg is set to null
243 if there is no error message. deflateInit does not perform any compression:
244 this will be done by deflate().
245*/
246
247
248ZEXTERN int ZEXPORT deflate(z_stream *strm, int flush);
249/*
250 deflate compresses as much data as possible, and stops when the input
251 buffer becomes empty or the output buffer becomes full. It may introduce
252 some output latency (reading input without producing any output) except when
253 forced to flush.
254
255 The detailed semantics are as follows. deflate performs one or both of the
256 following actions:
257
258 - Compress more input starting at next_in and update next_in and avail_in
259 accordingly. If not all input can be processed (because there is not
260 enough room in the output buffer), next_in and avail_in are updated and
261 processing will resume at this point for the next call of deflate().
262
263 - Generate more output starting at next_out and update next_out and avail_out
264 accordingly. This action is forced if the parameter flush is non zero.
265 Forcing flush frequently degrades the compression ratio, so this parameter
266 should be set only when necessary. Some output may be provided even if
267 flush is zero.
268
269 Before the call of deflate(), the application should ensure that at least
270 one of the actions is possible, by providing more input and/or consuming more
271 output, and updating avail_in or avail_out accordingly; avail_out should
272 never be zero before the call. The application can consume the compressed
273 output when it wants, for example when the output buffer is full (avail_out
274 == 0), or after each call of deflate(). If deflate returns Z_OK and with
275 zero avail_out, it must be called again after making room in the output
276 buffer because there might be more output pending. See deflatePending(),
277 which can be used if desired to determine whether or not there is more ouput
278 in that case.
279
280 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
281 decide how much data to accumulate before producing output, in order to
282 maximize compression.
283
284 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
285 flushed to the output buffer and the output is aligned on a byte boundary, so
286 that the decompressor can get all input data available so far. (In
287 particular avail_in is zero after the call if enough output space has been
288 provided before the call.) Flushing may degrade compression for some
289 compression algorithms and so it should be used only when necessary. This
290 completes the current deflate block and follows it with an empty stored block
291 that is three bits plus filler bits to the next byte, followed by four bytes
292 (00 00 ff ff).
293
294 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
295 output buffer, but the output is not aligned to a byte boundary. All of the
296 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
297 This completes the current deflate block and follows it with an empty fixed
298 codes block that is 10 bits long. This assures that enough bytes are output
299 in order for the decompressor to finish the block before the empty fixed
300 codes block.
301
302 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
303 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
304 seven bits of the current block are held to be written as the next byte after
305 the next deflate block is completed. In this case, the decompressor may not
306 be provided enough bits at this point in order to complete decompression of
307 the data provided so far to the compressor. It may need to wait for the next
308 block to be emitted. This is for advanced applications that need to control
309 the emission of deflate blocks.
310
311 If flush is set to Z_FULL_FLUSH, all output is flushed as with
312 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
313 restart from this point if previous compressed data has been damaged or if
314 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
315 compression.
316
317 If deflate returns with avail_out == 0, this function must be called again
318 with the same value of the flush parameter and more output space (updated
319 avail_out), until the flush is complete (deflate returns with non-zero
320 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
321 avail_out is greater than six to avoid repeated flush markers due to
322 avail_out == 0 on return.
323
324 If the parameter flush is set to Z_FINISH, pending input is processed,
325 pending output is flushed and deflate returns with Z_STREAM_END if there was
326 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this
327 function must be called again with Z_FINISH and more output space (updated
328 avail_out) but no more input data, until it returns with Z_STREAM_END or an
329 error. After deflate has returned Z_STREAM_END, the only possible operations
330 on the stream are deflateReset or deflateEnd.
331
332 Z_FINISH can be used in the first deflate call after deflateInit if all the
333 compression is to be done in a single step. In order to complete in one
334 call, avail_out must be at least the value returned by deflateBound (see
335 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough
336 output space is provided, deflate will not return Z_STREAM_END, and it must
337 be called again as described above.
338
339 deflate() sets strm->adler to the Adler-32 checksum of all input read
340 so far (that is, total_in bytes). If a gzip stream is being generated, then
341 strm->adler will be the CRC-32 checksum of the input read so far. (See
342 deflateInit2 below.)
343
344 deflate() may update strm->data_type if it can make a good guess about
345 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is
346 considered binary. This field is only for information purposes and does not
347 affect the compression algorithm in any manner.
348
349 deflate() returns Z_OK if some progress has been made (more input
350 processed or more output produced), Z_STREAM_END if all input has been
351 consumed and all output has been produced (only when flush is set to
352 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
353 if next_in or next_out was NULL) or the state was inadvertently written over
354 by the application), or Z_BUF_ERROR if no progress is possible (for example
355 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
356 deflate() can be called again with more input and more output space to
357 continue compressing.
358*/
359
360
361ZEXTERN int ZEXPORT deflateEnd(z_stream *strm);
362/*
363 All dynamically allocated data structures for this stream are freed.
364 This function discards any unprocessed input and does not flush any pending
365 output.
366
367 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
368 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
369 prematurely (some input or output was discarded). In the error case, msg
370 may be set but then points to a static string (which must not be
371 deallocated).
372*/
373
374
375/*
376ZEXTERN int ZEXPORT inflateInit (z_stream *strm);
377
378 Initializes the internal stream state for decompression. The fields
379 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
380 the caller. In the current version of inflate, the provided input is not
381 read or consumed. The allocation of a sliding window will be deferred to
382 the first call of inflate (if the decompression does not complete on the
383 first call). If zalloc and zfree are set to NULL, inflateInit updates
384 them to use default allocation functions.
385
386 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
387 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
388 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
389 invalid, such as a null pointer to the structure. msg is set to null if
390 there is no error message. inflateInit does not perform any decompression.
391 Actual decompression will be done by inflate(). So next_in, and avail_in,
392 next_out, and avail_out are unused and unchanged. The current
393 implementation of inflateInit() does not process any header information --
394 that is deferred until inflate() is called.
395*/
396
397
398ZEXTERN int ZEXPORT inflate(z_stream *strm, int flush);
399/*
400 inflate decompresses as much data as possible, and stops when the input
401 buffer becomes empty or the output buffer becomes full. It may introduce
402 some output latency (reading input without producing any output) except when
403 forced to flush.
404
405 The detailed semantics are as follows. inflate performs one or both of the
406 following actions:
407
408 - Decompress more input starting at next_in and update next_in and avail_in
409 accordingly. If not all input can be processed (because there is not
410 enough room in the output buffer), then next_in and avail_in are updated
411 accordingly, and processing will resume at this point for the next call of
412 inflate().
413
414 - Generate more output starting at next_out and update next_out and avail_out
415 accordingly. inflate() provides as much output as possible, until there is
416 no more input data or no more space in the output buffer (see below about
417 the flush parameter).
418
419 Before the call of inflate(), the application should ensure that at least
420 one of the actions is possible, by providing more input and/or consuming more
421 output, and updating the next_* and avail_* values accordingly. If the
422 caller of inflate() does not provide both available input and available
423 output space, it is possible that there will be no progress made. The
424 application can consume the uncompressed output when it wants, for example
425 when the output buffer is full (avail_out == 0), or after each call of
426 inflate(). If inflate returns Z_OK and with zero avail_out, it must be
427 called again after making room in the output buffer because there might be
428 more output pending.
429
430 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
431 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
432 output as possible to the output buffer. Z_BLOCK requests that inflate()
433 stop if and when it gets to the next deflate block boundary. When decoding
434 the zlib or gzip format, this will cause inflate() to return immediately
435 after the header and before the first block. When doing a raw inflate,
436 inflate() will go ahead and process the first block, and will return when it
437 gets to the end of that block, or when it runs out of data.
438
439 The Z_BLOCK option assists in appending to or combining deflate streams.
440 To assist in this, on return inflate() always sets strm->data_type to the
441 number of unused bits in the last byte taken from strm->next_in, plus 64 if
442 inflate() is currently decoding the last block in the deflate stream, plus
443 128 if inflate() returned immediately after decoding an end-of-block code or
444 decoding the complete header up to just before the first byte of the deflate
445 stream. The end-of-block will not be indicated until all of the uncompressed
446 data from that block has been written to strm->next_out. The number of
447 unused bits may in general be greater than seven, except when bit 7 of
448 data_type is set, in which case the number of unused bits will be less than
449 eight. data_type is set as noted here every time inflate() returns for all
450 flush options, and so can be used to determine the amount of currently
451 consumed input in bits.
452
453 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
454 end of each deflate block header is reached, before any actual data in that
455 block is decoded. This allows the caller to determine the length of the
456 deflate block header for later use in random access within a deflate block.
457 256 is added to the value of strm->data_type when inflate() returns
458 immediately after reaching the end of the deflate block header.
459
460 inflate() should normally be called until it returns Z_STREAM_END or an
461 error. However if all decompression is to be performed in a single step (a
462 single call of inflate), the parameter flush should be set to Z_FINISH. In
463 this case all pending input is processed and all pending output is flushed;
464 avail_out must be large enough to hold all of the uncompressed data for the
465 operation to complete. (The size of the uncompressed data may have been
466 saved by the compressor for this purpose.) The use of Z_FINISH is not
467 required to perform an inflation in one step. However it may be used to
468 inform inflate that a faster approach can be used for the single inflate()
469 call. Z_FINISH also informs inflate to not maintain a sliding window if the
470 stream completes, which reduces inflate's memory footprint. If the stream
471 does not complete, either because not all of the stream is provided or not
472 enough output space is provided, then a sliding window will be allocated and
473 inflate() can be called again to continue the operation as if Z_NO_FLUSH had
474 been used.
475
476 In this implementation, inflate() always flushes as much output as
477 possible to the output buffer, and always uses the faster approach on the
478 first call. So the effects of the flush parameter in this implementation are
479 on the return value of inflate() as noted below, when inflate() returns early
480 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
481 memory for a sliding window when Z_FINISH is used.
482
483 If a preset dictionary is needed after this call (see inflateSetDictionary
484 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
485 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
486 strm->adler to the Adler-32 checksum of all output produced so far (that is,
487 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
488 below. At the end of the stream, inflate() checks that its computed Adler-32
489 checksum is equal to that saved by the compressor and returns Z_STREAM_END
490 only if the checksum is correct.
491
492 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
493 deflate data. The header type is detected automatically, if requested when
494 initializing with inflateInit2(). Any information contained in the gzip
495 header is not retained unless inflateGetHeader() is used. When processing
496 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
497 produced so far. The CRC-32 is checked against the gzip trailer, as is the
498 uncompressed length, modulo 2^32.
499
500 inflate() returns Z_OK if some progress has been made (more input processed
501 or more output produced), Z_STREAM_END if the end of the compressed data has
502 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
503 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
504 corrupted (input stream not conforming to the zlib format or incorrect check
505 value, in which case strm->msg points to a string with a more specific
506 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
507 next_in or next_out was NULL, or the state was inadvertently written over
508 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
509 if no progress is possible or if there was not enough room in the output
510 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
511 inflate() can be called again with more input and more output space to
512 continue decompressing. If Z_DATA_ERROR is returned, the application may
513 then call inflateSync() to look for a good compression block if a partial
514 recovery of the data is to be attempted.
515*/
516
517
518ZEXTERN int ZEXPORT inflateEnd(z_stream *strm);
519/*
520 All dynamically allocated data structures for this stream are freed.
521 This function discards any unprocessed input and does not flush any pending
522 output.
523
524 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
525 was inconsistent.
526*/
527
528
529 /* Advanced functions */
530
531/*
532 The following functions are needed only in some special applications.
533*/
534
535/*
536ZEXTERN int ZEXPORT deflateInit2 (z_stream *strm,
537 int level,
538 int method,
539 int windowBits,
540 int memLevel,
541 int strategy);
542
543 This is another version of deflateInit with more compression options. The
544 fields zalloc, zfree and opaque must be initialized before by the caller.
545
546 The method parameter is the compression method. It must be Z_DEFLATED in
547 this version of the library.
548
549 The windowBits parameter is the base two logarithm of the window size
550 (the size of the history buffer). It should be in the range 8..15 for this
551 version of the library. Larger values of this parameter result in better
552 compression at the expense of memory usage. The default value is 15 if
553 deflateInit is used instead.
554
555 For the current implementation of deflate(), a windowBits value of 8 (a
556 window size of 256 bytes) is not supported. As a result, a request for 8
557 will result in 9 (a 512-byte window). In that case, providing 8 to
558 inflateInit2() will result in an error when the zlib header with 9 is
559 checked against the initialization of inflate(). The remedy is to not use 8
560 with deflateInit2() with this initialization, or at least in that case use 9
561 with inflateInit2().
562
563 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
564 determines the window size. deflate() will then generate raw deflate data
565 with no zlib header or trailer, and will not compute a check value.
566
567 windowBits can also be greater than 15 for optional gzip encoding. Add
568 16 to windowBits to write a simple gzip header and trailer around the
569 compressed data instead of a zlib wrapper. The gzip header will have no
570 file name, no extra data, no comment, no modification time (set to zero), no
571 header crc, and the operating system will be set to the appropriate value,
572 if the operating system was determined at compile time. If a gzip stream is
573 being written, strm->adler is a CRC-32 instead of an Adler-32.
574
575 For raw deflate or gzip encoding, a request for a 256-byte window is
576 rejected as invalid, since only the zlib header provides a means of
577 transmitting the window size to the decompressor.
578
579 The memLevel parameter specifies how much memory should be allocated
580 for the internal compression state. memLevel=1 uses minimum memory but is
581 slow and reduces compression ratio; memLevel=9 uses maximum memory for
582 optimal speed. The default value is 8. See zconf.h for total memory usage
583 as a function of windowBits and memLevel.
584
585 The strategy parameter is used to tune the compression algorithm. Use the
586 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
587 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
588 string match), or Z_RLE to limit match distances to one (run-length
589 encoding). Filtered data consists mostly of small values with a somewhat
590 random distribution. In this case, the compression algorithm is tuned to
591 compress them better. The effect of Z_FILTERED is to force more Huffman
592 coding and less string matching; it is somewhat intermediate between
593 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
594 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
595 strategy parameter only affects the compression ratio but not the
596 correctness of the compressed output even if it is not set appropriately.
597 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
598 decoder for special applications.
599
600 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
601 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
602 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
603 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
604 set to null if there is no error message. deflateInit2 does not perform any
605 compression: this will be done by deflate().
606*/
607
608ZEXTERN int ZEXPORT deflateSetDictionary(z_stream *strm,
609 const unsigned char *dictionary,
610 unsigned int dictLength);
611/*
612 Initializes the compression dictionary from the given byte sequence
613 without producing any compressed output. When using the zlib format, this
614 function must be called immediately after deflateInit, deflateInit2 or
615 deflateReset, and before any call of deflate. When doing raw deflate, this
616 function must be called either before any call of deflate, or immediately
617 after the completion of a deflate block, i.e. after all input has been
618 consumed and all output has been delivered when using any of the flush
619 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
620 compressor and decompressor must use exactly the same dictionary (see
621 inflateSetDictionary).
622
623 The dictionary should consist of strings (byte sequences) that are likely
624 to be encountered later in the data to be compressed, with the most commonly
625 used strings preferably put towards the end of the dictionary. Using a
626 dictionary is most useful when the data to be compressed is short and can be
627 predicted with good accuracy; the data can then be compressed better than
628 with the default empty dictionary.
629
630 Depending on the size of the compression data structures selected by
631 deflateInit or deflateInit2, a part of the dictionary may in effect be
632 discarded, for example if the dictionary is larger than the window size
633 provided in deflateInit or deflateInit2. Thus the strings most likely to be
634 useful should be put at the end of the dictionary, not at the front. In
635 addition, the current implementation of deflate will use at most the window
636 size minus 262 bytes of the provided dictionary.
637
638 Upon return of this function, strm->adler is set to the Adler-32 value
639 of the dictionary; the decompressor may later use this value to determine
640 which dictionary has been used by the compressor. (The Adler-32 value
641 applies to the whole dictionary even if only a subset of the dictionary is
642 actually used by the compressor.) If a raw deflate was requested, then the
643 Adler-32 value is not computed and strm->adler is not set.
644
645 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
646 parameter is invalid (e.g. dictionary being NULL) or the stream state is
647 inconsistent (for example if deflate has already been called for this stream
648 or if not at a block boundary for raw deflate). deflateSetDictionary does
649 not perform any compression: this will be done by deflate().
650*/
651
652ZEXTERN int ZEXPORT deflateGetDictionary (z_stream *strm, unsigned char *dictionary, unsigned int *dictLength);
653/*
654 Returns the sliding dictionary being maintained by deflate. dictLength is
655 set to the number of bytes in the dictionary, and that many bytes are copied
656 to dictionary. dictionary must have enough space, where 32768 bytes is
657 always enough. If deflateGetDictionary() is called with dictionary equal to
658 Z_NULL, then only the dictionary length is returned, and nothing is copied.
659 Similary, if dictLength is Z_NULL, then it is not set.
660
661 deflateGetDictionary() may return a length less than the window size, even
662 when more than the window size in input has been provided. It may return up
663 to 258 bytes less in that case, due to how zlib's implementation of deflate
664 manages the sliding window and lookahead for matches, where matches can be
665 up to 258 bytes long. If the application needs the last window-size bytes of
666 input, then that would need to be saved by the application outside of zlib.
667
668 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
669 stream state is inconsistent.
670*/
671
672ZEXTERN int ZEXPORT deflateCopy(z_stream *dest, z_stream *source);
673/*
674 Sets the destination stream as a complete copy of the source stream.
675
676 This function can be useful when several compression strategies will be
677 tried, for example when there are several ways of pre-processing the input
678 data with a filter. The streams that will be discarded should then be freed
679 by calling deflateEnd. Note that deflateCopy duplicates the internal
680 compression state which can be quite large, so this strategy is slow and can
681 consume lots of memory.
682
683 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
684 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
685 (such as zalloc being NULL). msg is left unchanged in both source and
686 destination.
687*/
688
689ZEXTERN int ZEXPORT deflateReset(z_stream *strm);
690/*
691 This function is equivalent to deflateEnd followed by deflateInit, but
692 does not free and reallocate the internal compression state. The stream
693 will leave the compression level and any other attributes that may have been
694 set unchanged.
695
696 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
697 stream state was inconsistent (such as zalloc or state being NULL).
698*/
699
700ZEXTERN int ZEXPORT deflateParams(z_stream *strm, int level, int strategy);
701/*
702 Dynamically update the compression level and compression strategy. The
703 interpretation of level and strategy is as in deflateInit2(). This can be
704 used to switch between compression and straight copy of the input data, or
705 to switch to a different kind of input data requiring a different strategy.
706 If the compression approach (which is a function of the level) or the
707 strategy is changed, and if there have been any deflate() calls since the
708 state was initialized or reset, then the input available so far is
709 compressed with the old level and strategy using deflate(strm, Z_BLOCK).
710 There are three approaches for the compression levels 0, 1..3, and 4..9
711 respectively. The new level and strategy will take effect at the next call
712 of deflate().
713
714 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
715 not have enough output space to complete, then the parameter change will not
716 take effect. In this case, deflateParams() can be called again with the
717 same parameters and more output space to try again.
718
719 In order to assure a change in the parameters on the first try, the
720 deflate stream should be flushed using deflate() with Z_BLOCK or other flush
721 request until strm.avail_out is not zero, before calling deflateParams().
722 Then no more input data should be provided before the deflateParams() call.
723 If this is done, the old level and strategy will be applied to the data
724 compressed before deflateParams(), and the new level and strategy will be
725 applied to the the data compressed after deflateParams().
726
727 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
728 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
729 there was not enough output space to complete the compression of the
730 available input data before a change in the strategy or approach. Note that
731 in the case of a Z_BUF_ERROR, the parameters are not changed. A return
732 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
733 retried with more output space.
734*/
735
736ZEXTERN int ZEXPORT deflateTune(z_stream *strm, int good_length, int max_lazy, int nice_length, int max_chain);
737/*
738 Fine tune deflate's internal compression parameters. This should only be
739 used by someone who understands the algorithm used by zlib's deflate for
740 searching for the best matching string, and even then only by the most
741 fanatic optimizer trying to squeeze out the last compressed bit for their
742 specific input data. Read the deflate.c source code for the meaning of the
743 max_lazy, good_length, nice_length, and max_chain parameters.
744
745 deflateTune() can be called after deflateInit() or deflateInit2(), and
746 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
747 */
748
749ZEXTERN unsigned long ZEXPORT deflateBound(z_stream *strm, unsigned long sourceLen);
750/*
751 deflateBound() returns an upper bound on the compressed size after
752 deflation of sourceLen bytes. It must be called after deflateInit() or
753 deflateInit2(), and after deflateSetHeader(), if used. This would be used
754 to allocate an output buffer for deflation in a single pass, and so would be
755 called before deflate(). If that first deflate() call is provided the
756 sourceLen input bytes, an output buffer allocated to the size returned by
757 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
758 to return Z_STREAM_END. Note that it is possible for the compressed size to
759 be larger than the value returned by deflateBound() if flush options other
760 than Z_FINISH or Z_NO_FLUSH are used.
761*/
762
763ZEXTERN int ZEXPORT deflatePending(z_stream *strm, uint32_t *pending, int *bits);
764/*
765 deflatePending() returns the number of bytes and bits of output that have
766 been generated, but not yet provided in the available output. The bytes not
767 provided would be due to the available output space having being consumed.
768 The number of bits of output not provided are between 0 and 7, where they
769 await more bits to join them in order to fill out a full byte. If pending
770 or bits are NULL, then those values are not set.
771
772 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
773 stream state was inconsistent.
774 */
775
776ZEXTERN int ZEXPORT deflatePrime(z_stream *strm, int bits, int value);
777/*
778 deflatePrime() inserts bits in the deflate output stream. The intent
779 is that this function is used to start off the deflate output with the bits
780 leftover from a previous deflate stream when appending to it. As such, this
781 function can only be used for raw deflate, and must be used before the first
782 deflate() call after a deflateInit2() or deflateReset(). bits must be less
783 than or equal to 16, and that many of the least significant bits of value
784 will be inserted in the output.
785
786 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
787 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
788 source stream state was inconsistent.
789*/
790
791ZEXTERN int ZEXPORT deflateSetHeader(z_stream *strm, gz_headerp head);
792/*
793 deflateSetHeader() provides gzip header information for when a gzip
794 stream is requested by deflateInit2(). deflateSetHeader() may be called
795 after deflateInit2() or deflateReset() and before the first call of
796 deflate(). The text, time, os, extra field, name, and comment information
797 in the provided gz_header structure are written to the gzip header (xflag is
798 ignored -- the extra flags are set according to the compression level). The
799 caller must assure that, if not NULL, name and comment are terminated with
800 a zero byte, and that if extra is not NULL, that extra_len bytes are
801 available there. If hcrc is true, a gzip header crc is included. Note that
802 the current versions of the command-line version of gzip (up through version
803 1.3.x) do not support header crc's, and will report that it is a "multi-part
804 gzip file" and give up.
805
806 If deflateSetHeader is not used, the default gzip header has text false,
807 the time set to zero, and os set to 255, with no extra, name, or comment
808 fields. The gzip header is returned to the default state by deflateReset().
809
810 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
811 stream state was inconsistent.
812*/
813
814/*
815ZEXTERN int ZEXPORT inflateInit2(z_stream *strm, int windowBits);
816
817 This is another version of inflateInit with an extra parameter. The
818 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
819 before by the caller.
820
821 The windowBits parameter is the base two logarithm of the maximum window
822 size (the size of the history buffer). It should be in the range 8..15 for
823 this version of the library. The default value is 15 if inflateInit is used
824 instead. windowBits must be greater than or equal to the windowBits value
825 provided to deflateInit2() while compressing, or it must be equal to 15 if
826 deflateInit2() was not used. If a compressed stream with a larger window
827 size is given as input, inflate() will return with the error code
828 Z_DATA_ERROR instead of trying to allocate a larger window.
829
830 windowBits can also be zero to request that inflate use the window size in
831 the zlib header of the compressed stream.
832
833 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
834 determines the window size. inflate() will then process raw deflate data,
835 not looking for a zlib or gzip header, not generating a check value, and not
836 looking for any check values for comparison at the end of the stream. This
837 is for use with other formats that use the deflate compressed data format
838 such as zip. Those formats provide their own check values. If a custom
839 format is developed using the raw deflate format for compressed data, it is
840 recommended that a check value such as an Adler-32 or a CRC-32 be applied to
841 the uncompressed data as is done in the zlib, gzip, and zip formats. For
842 most applications, the zlib format should be used as is. Note that comments
843 above on the use in deflateInit2() applies to the magnitude of windowBits.
844
845 windowBits can also be greater than 15 for optional gzip decoding. Add
846 32 to windowBits to enable zlib and gzip decoding with automatic header
847 detection, or add 16 to decode only the gzip format (the zlib format will
848 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
849 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see
850 below), inflate() will *not* automatically decode concatenated gzip members.
851 inflate() will return Z_STREAM_END at the end of the gzip member. The state
852 would need to be reset to continue decoding a subsequent gzip member. This
853 *must* be done if there is more data after a gzip member, in order for the
854 decompression to be compliant with the gzip standard (RFC 1952).
855
856 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
857 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
858 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
859 invalid, such as a null pointer to the structure. msg is set to null if
860 there is no error message. inflateInit2 does not perform any decompression
861 apart from possibly reading the zlib header if present: actual decompression
862 will be done by inflate(). (So next_in and avail_in may be modified, but
863 next_out and avail_out are unused and unchanged.) The current implementation
864 of inflateInit2() does not process any header information -- that is
865 deferred until inflate() is called.
866*/
867
868ZEXTERN int ZEXPORT inflateSetDictionary(z_stream *strm, const unsigned char *dictionary, unsigned int dictLength);
869/*
870 Initializes the decompression dictionary from the given uncompressed byte
871 sequence. This function must be called immediately after a call of inflate,
872 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
873 can be determined from the Adler-32 value returned by that call of inflate.
874 The compressor and decompressor must use exactly the same dictionary (see
875 deflateSetDictionary). For raw inflate, this function can be called at any
876 time to set the dictionary. If the provided dictionary is smaller than the
877 window and there is already data in the window, then the provided dictionary
878 will amend what's there. The application must insure that the dictionary
879 that was used for compression is provided.
880
881 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
882 parameter is invalid (e.g. dictionary being NULL) or the stream state is
883 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
884 expected one (incorrect Adler-32 value). inflateSetDictionary does not
885 perform any decompression: this will be done by subsequent calls of
886 inflate().
887*/
888
889ZEXTERN int ZEXPORT inflateGetDictionary(z_stream *strm, unsigned char *dictionary, unsigned int *dictLength);
890/*
891 Returns the sliding dictionary being maintained by inflate. dictLength is
892 set to the number of bytes in the dictionary, and that many bytes are copied
893 to dictionary. dictionary must have enough space, where 32768 bytes is
894 always enough. If inflateGetDictionary() is called with dictionary equal to
895 NULL, then only the dictionary length is returned, and nothing is copied.
896 Similary, if dictLength is NULL, then it is not set.
897
898 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
899 stream state is inconsistent.
900*/
901
902ZEXTERN int ZEXPORT inflateSync(z_stream *strm);
903/*
904 Skips invalid compressed data until a possible full flush point (see above
905 for the description of deflate with Z_FULL_FLUSH) can be found, or until all
906 available input is skipped. No output is provided.
907
908 inflateSync searches for a 00 00 FF FF pattern in the compressed data.
909 All full flush points have this pattern, but not all occurrences of this
910 pattern are full flush points.
911
912 inflateSync returns Z_OK if a possible full flush point has been found,
913 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
914 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
915 In the success case, the application may save the current current value of
916 total_in which indicates where valid compressed data was found. In the
917 error case, the application may repeatedly call inflateSync, providing more
918 input each time, until success or end of the input data.
919*/
920
921ZEXTERN int ZEXPORT inflateCopy(z_stream *dest, z_stream *source);
922/*
923 Sets the destination stream as a complete copy of the source stream.
924
925 This function can be useful when randomly accessing a large stream. The
926 first pass through the stream can periodically record the inflate state,
927 allowing restarting inflate at those points when randomly accessing the
928 stream.
929
930 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
931 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
932 (such as zalloc being NULL). msg is left unchanged in both source and
933 destination.
934*/
935
936ZEXTERN int ZEXPORT inflateReset(z_stream *strm);
937/*
938 This function is equivalent to inflateEnd followed by inflateInit,
939 but does not free and reallocate the internal decompression state. The
940 stream will keep attributes that may have been set by inflateInit2.
941
942 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
943 stream state was inconsistent (such as zalloc or state being NULL).
944*/
945
946ZEXTERN int ZEXPORT inflateReset2(z_stream *strm, int windowBits);
947/*
948 This function is the same as inflateReset, but it also permits changing
949 the wrap and window size requests. The windowBits parameter is interpreted
950 the same as it is for inflateInit2. If the window size is changed, then the
951 memory allocated for the window is freed, and the window will be reallocated
952 by inflate() if needed.
953
954 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
955 stream state was inconsistent (such as zalloc or state being NULL), or if
956 the windowBits parameter is invalid.
957*/
958
959ZEXTERN int ZEXPORT inflatePrime(z_stream *strm, int bits, int value);
960/*
961 This function inserts bits in the inflate input stream. The intent is
962 that this function is used to start inflating at a bit position in the
963 middle of a byte. The provided bits will be used before any bytes are used
964 from next_in. This function should only be used with raw inflate, and
965 should be used before the first inflate() call after inflateInit2() or
966 inflateReset(). bits must be less than or equal to 16, and that many of the
967 least significant bits of value will be inserted in the input.
968
969 If bits is negative, then the input stream bit buffer is emptied. Then
970 inflatePrime() can be called again to put bits in the buffer. This is used
971 to clear out bits leftover after feeding inflate a block description prior
972 to feeding inflate codes.
973
974 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
975 stream state was inconsistent.
976*/
977
978ZEXTERN long ZEXPORT inflateMark(z_stream *strm);
979/*
980 This function returns two values, one in the lower 16 bits of the return
981 value, and the other in the remaining upper bits, obtained by shifting the
982 return value down 16 bits. If the upper value is -1 and the lower value is
983 zero, then inflate() is currently decoding information outside of a block.
984 If the upper value is -1 and the lower value is non-zero, then inflate is in
985 the middle of a stored block, with the lower value equaling the number of
986 bytes from the input remaining to copy. If the upper value is not -1, then
987 it is the number of bits back from the current bit position in the input of
988 the code (literal or length/distance pair) currently being processed. In
989 that case the lower value is the number of bytes already emitted for that
990 code.
991
992 A code is being processed if inflate is waiting for more input to complete
993 decoding of the code, or if it has completed decoding but is waiting for
994 more output space to write the literal or match data.
995
996 inflateMark() is used to mark locations in the input data for random
997 access, which may be at bit positions, and to note those cases where the
998 output of a code may span boundaries of random access blocks. The current
999 location in the input stream can be determined from avail_in and data_type
1000 as noted in the description for the Z_BLOCK flush parameter for inflate.
1001
1002 inflateMark returns the value noted above, or -65536 if the provided
1003 source stream state was inconsistent.
1004*/
1005
1006ZEXTERN int ZEXPORT inflateGetHeader(z_stream *strm, gz_headerp head);
1007/*
1008 inflateGetHeader() requests that gzip header information be stored in the
1009 provided gz_header structure. inflateGetHeader() may be called after
1010 inflateInit2() or inflateReset(), and before the first call of inflate().
1011 As inflate() processes the gzip stream, head->done is zero until the header
1012 is completed, at which time head->done is set to one. If a zlib stream is
1013 being decoded, then head->done is set to -1 to indicate that there will be
1014 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
1015 used to force inflate() to return immediately after header processing is
1016 complete and before any actual data is decompressed.
1017
1018 The text, time, xflags, and os fields are filled in with the gzip header
1019 contents. hcrc is set to true if there is a header CRC. (The header CRC
1020 was valid if done is set to one.) If extra is not NULL, then extra_max
1021 contains the maximum number of bytes to write to extra. Once done is true,
1022 extra_len contains the actual extra field length, and extra contains the
1023 extra field, or that field truncated if extra_max is less than extra_len.
1024 If name is not NULL, then up to name_max characters are written there,
1025 terminated with a zero unless the length is greater than name_max. If
1026 comment is not NULL, then up to comm_max characters are written there,
1027 terminated with a zero unless the length is greater than comm_max. When any
1028 of extra, name, or comment are not NULL and the respective field is not
1029 present in the header, then that field is set to NULL to signal its
1030 absence. This allows the use of deflateSetHeader() with the returned
1031 structure to duplicate the header. However if those fields are set to
1032 allocated memory, then the application will need to save those pointers
1033 elsewhere so that they can be eventually freed.
1034
1035 If inflateGetHeader is not used, then the header information is simply
1036 discarded. The header is always checked for validity, including the header
1037 CRC if present. inflateReset() will reset the process to discard the header
1038 information. The application would need to call inflateGetHeader() again to
1039 retrieve the header from the next gzip stream.
1040
1041 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1042 stream state was inconsistent.
1043*/
1044
1045/*
1046ZEXTERN int ZEXPORT inflateBackInit (z_stream *strm, int windowBits, unsigned char *window);
1047
1048 Initialize the internal stream state for decompression using inflateBack()
1049 calls. The fields zalloc, zfree and opaque in strm must be initialized
1050 before the call. If zalloc and zfree are NULL, then the default library-
1051 derived memory allocation routines are used. windowBits is the base two
1052 logarithm of the window size, in the range 8..15. window is a caller
1053 supplied buffer of that size. Except for special applications where it is
1054 assured that deflate was used with small window sizes, windowBits must be 15
1055 and a 32K byte window must be supplied to be able to decompress general
1056 deflate streams.
1057
1058 See inflateBack() for the usage of these routines.
1059
1060 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1061 the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1062 allocated, or Z_VERSION_ERROR if the version of the library does not match
1063 the version of the header file.
1064*/
1065
1066typedef uint32_t (*in_func) (void *, const unsigned char * *);
1067typedef int (*out_func) (void *, unsigned char *, uint32_t);
1068
1069ZEXTERN int ZEXPORT inflateBack(z_stream *strm, in_func in, void *in_desc, out_func out, void *out_desc);
1070/*
1071 inflateBack() does a raw inflate with a single call using a call-back
1072 interface for input and output. This is potentially more efficient than
1073 inflate() for file i/o applications, in that it avoids copying between the
1074 output and the sliding window by simply making the window itself the output
1075 buffer. inflate() can be faster on modern CPUs when used with large
1076 buffers. inflateBack() trusts the application to not change the output
1077 buffer passed by the output function, at least until inflateBack() returns.
1078
1079 inflateBackInit() must be called first to allocate the internal state
1080 and to initialize the state with the user-provided window buffer.
1081 inflateBack() may then be used multiple times to inflate a complete, raw
1082 deflate stream with each call. inflateBackEnd() is then called to free the
1083 allocated state.
1084
1085 A raw deflate stream is one with no zlib or gzip header or trailer.
1086 This routine would normally be used in a utility that reads zip or gzip
1087 files and writes out uncompressed files. The utility would decode the
1088 header and process the trailer on its own, hence this routine expects only
1089 the raw deflate stream to decompress. This is different from the default
1090 behavior of inflate(), which expects a zlib header and trailer around the
1091 deflate stream.
1092
1093 inflateBack() uses two subroutines supplied by the caller that are then
1094 called by inflateBack() for input and output. inflateBack() calls those
1095 routines until it reads a complete deflate stream and writes out all of the
1096 uncompressed data, or until it encounters an error. The function's
1097 parameters and return types are defined above in the in_func and out_func
1098 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1099 number of bytes of provided input, and a pointer to that input in buf. If
1100 there is no input available, in() must return zero -- buf is ignored in that
1101 case -- and inflateBack() will return a buffer error. inflateBack() will
1102 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
1103 out() should return zero on success, or non-zero on failure. If out()
1104 returns non-zero, inflateBack() will return with an error. Neither in() nor
1105 out() are permitted to change the contents of the window provided to
1106 inflateBackInit(), which is also the buffer that out() uses to write from.
1107 The length written by out() will be at most the window size. Any non-zero
1108 amount of input may be provided by in().
1109
1110 For convenience, inflateBack() can be provided input on the first call by
1111 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1112 in() will be called. Therefore strm->next_in must be initialized before
1113 calling inflateBack(). If strm->next_in is NULL, then in() will be called
1114 immediately for input. If strm->next_in is not NULL, then strm->avail_in
1115 must also be initialized, and then if strm->avail_in is not zero, input will
1116 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1117
1118 The in_desc and out_desc parameters of inflateBack() is passed as the
1119 first parameter of in() and out() respectively when they are called. These
1120 descriptors can be optionally used to pass any information that the caller-
1121 supplied in() and out() functions need to do their job.
1122
1123 On return, inflateBack() will set strm->next_in and strm->avail_in to
1124 pass back any unused input that was provided by the last in() call. The
1125 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1126 if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1127 in the deflate stream (in which case strm->msg is set to indicate the nature
1128 of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1129 In the case of Z_BUF_ERROR, an input or output error can be distinguished
1130 using strm->next_in which will be NULL only if in() returned an error. If
1131 strm->next_in is not NULL, then the Z_BUF_ERROR was due to out() returning
1132 non-zero. (in() will always be called before out(), so strm->next_in is
1133 assured to be defined if out() returns non-zero.) Note that inflateBack()
1134 cannot return Z_OK.
1135*/
1136
1137ZEXTERN int ZEXPORT inflateBackEnd(z_stream *strm);
1138/*
1139 All memory allocated by inflateBackInit() is freed.
1140
1141 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1142 state was inconsistent.
1143*/
1144
1145ZEXTERN unsigned long ZEXPORT zlibCompileFlags(void);
1146/* Return flags indicating compile-time options.
1147
1148 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1149 1.0: size of unsigned int
1150 3.2: size of unsigned long
1151 5.4: size of void * (pointer)
1152 7.6: size of z_off_t
1153
1154 Compiler, assembler, and debug options:
1155 8: ZLIB_DEBUG
1156 9: ASMV or ASMINF -- use ASM code
1157 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1158 11: 0 (reserved)
1159
1160 One-time table building (smaller code, but not thread-safe if true):
1161 12: BUILDFIXED -- build static block decoding tables when needed (not supported by zlib-ng)
1162 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1163 14,15: 0 (reserved)
1164
1165 Library content (indicates missing functionality):
1166 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1167 deflate code when not needed)
1168 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1169 and decode gzip streams (to avoid linking crc code)
1170 18-19: 0 (reserved)
1171
1172 Operation variations (changes in library functionality):
1173 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1174 21: FASTEST -- deflate algorithm with only one, lowest compression level
1175 22,23: 0 (reserved)
1176
1177 The sprintf variant used by gzprintf (zero is best):
1178 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1179 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1180 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1181
1182 Remainder:
1183 27-31: 0 (reserved)
1184 */
1185
1186
1187 /* utility functions */
1188
1189/*
1190 The following utility functions are implemented on top of the basic
1191 stream-oriented functions. To simplify the interface, some default options
1192 are assumed (compression level and memory usage, standard memory allocation
1193 functions). The source code of these utility functions can be modified if
1194 you need special options.
1195*/
1196
1197ZEXTERN int ZEXPORT compress(unsigned char *dest, unsigned long *destLen, const unsigned char *source, unsigned long sourceLen);
1198/*
1199 Compresses the source buffer into the destination buffer. sourceLen is
1200 the byte length of the source buffer. Upon entry, destLen is the total size
1201 of the destination buffer, which must be at least the value returned by
1202 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1203 compressed data. compress() is equivalent to compress2() with a level
1204 parameter of Z_DEFAULT_COMPRESSION.
1205
1206 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1207 enough memory, Z_BUF_ERROR if there was not enough room in the output
1208 buffer.
1209*/
1210
1211ZEXTERN int ZEXPORT compress2(unsigned char *dest, unsigned long *destLen, const unsigned char *source,
1212 unsigned long sourceLen, int level);
1213/*
1214 Compresses the source buffer into the destination buffer. The level
1215 parameter has the same meaning as in deflateInit. sourceLen is the byte
1216 length of the source buffer. Upon entry, destLen is the total size of the
1217 destination buffer, which must be at least the value returned by
1218 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1219 compressed data.
1220
1221 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1222 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1223 Z_STREAM_ERROR if the level parameter is invalid.
1224*/
1225
1226ZEXTERN unsigned long ZEXPORT compressBound(unsigned long sourceLen);
1227/*
1228 compressBound() returns an upper bound on the compressed size after
1229 compress() or compress2() on sourceLen bytes. It would be used before a
1230 compress() or compress2() call to allocate the destination buffer.
1231*/
1232
1233ZEXTERN int ZEXPORT uncompress(unsigned char *dest, unsigned long *destLen, const unsigned char *source, unsigned long sourceLen);
1234/*
1235 Decompresses the source buffer into the destination buffer. sourceLen is
1236 the byte length of the source buffer. Upon entry, destLen is the total size
1237 of the destination buffer, which must be large enough to hold the entire
1238 uncompressed data. (The size of the uncompressed data must have been saved
1239 previously by the compressor and transmitted to the decompressor by some
1240 mechanism outside the scope of this compression library.) Upon exit, destLen
1241 is the actual size of the uncompressed data.
1242
1243 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1244 enough memory, Z_BUF_ERROR if there was not enough room in the output
1245 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1246 the case where there is not enough room, uncompress() will fill the output
1247 buffer with the uncompressed data up to that point.
1248*/
1249
1250
1251ZEXTERN int ZEXPORT uncompress2 (unsigned char *dest, unsigned long *destLen,
1252 const unsigned char *source, unsigned long *sourceLen);
1253/*
1254 Same as uncompress, except that sourceLen is a pointer, where the
1255 length of the source is *sourceLen. On return, *sourceLen is the number of
1256 source bytes consumed.
1257*/
1258
1259
1260 /* gzip file access functions */
1261
1262/*
1263 This library supports reading and writing files in gzip (.gz) format with
1264 an interface similar to that of stdio, using the functions that start with
1265 "gz". The gzip format is different from the zlib format. gzip is a gzip
1266 wrapper, documented in RFC 1952, wrapped around a deflate stream.
1267*/
1268
1269typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1270
1271/*
1272ZEXTERN gzFile ZEXPORT gzopen(const char *path, const char *mode);
1273
1274 Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1275 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1276 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1277 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1278 for fixed code compression as in "wb9F". (See the description of
1279 deflateInit2 for more information about the strategy parameter.) 'T' will
1280 request transparent writing or appending with no compression and not using
1281 the gzip format.
1282
1283 "a" can be used instead of "w" to request that the gzip stream that will
1284 be written be appended to the file. "+" will result in an error, since
1285 reading and writing to the same gzip file is not supported. The addition of
1286 "x" when writing will create the file exclusively, which fails if the file
1287 already exists. On systems that support it, the addition of "e" when
1288 reading or writing will set the flag to close the file on an execve() call.
1289
1290 These functions, as well as gzip, will read and decode a sequence of gzip
1291 streams in a file. The append function of gzopen() can be used to create
1292 such a file. (Also see gzflush() for another way to do this.) When
1293 appending, gzopen does not test whether the file begins with a gzip stream,
1294 nor does it look for the end of the gzip streams to begin appending. gzopen
1295 will simply append a gzip stream to the existing file.
1296
1297 gzopen can be used to read a file which is not in gzip format; in this
1298 case gzread will directly read from the file without decompression. When
1299 reading, this will be detected automatically by looking for the magic two-
1300 byte gzip header.
1301
1302 gzopen returns NULL if the file could not be opened, if there was
1303 insufficient memory to allocate the gzFile state, or if an invalid mode was
1304 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1305 errno can be checked to determine if the reason gzopen failed was that the
1306 file could not be opened.
1307*/
1308
1309ZEXTERN gzFile ZEXPORT gzdopen(int fd, const char *mode);
1310/*
1311 gzdopen associates a gzFile with the file descriptor fd. File descriptors
1312 are obtained from calls like open, dup, creat, pipe or fileno (if the file
1313 has been previously opened with fopen). The mode parameter is as in gzopen.
1314
1315 The next call of gzclose on the returned gzFile will also close the file
1316 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1317 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1318 mode);. The duplicated descriptor should be saved to avoid a leak, since
1319 gzdopen does not close fd if it fails. If you are using fileno() to get the
1320 file descriptor from a FILE *, then you will have to use dup() to avoid
1321 double-close()ing the file descriptor. Both gzclose() and fclose() will
1322 close the associated file descriptor, so they need to have different file
1323 descriptors.
1324
1325 gzdopen returns NULL if there was insufficient memory to allocate the
1326 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1327 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1328 used until the next gz* read, write, seek, or close operation, so gzdopen
1329 will not detect if fd is invalid (unless fd is -1).
1330*/
1331
1332ZEXTERN int ZEXPORT gzbuffer(gzFile file, unsigned size);
1333/*
1334 Set the internal buffer size used by this library's functions. The
1335 default buffer size is 8192 bytes. This function must be called after
1336 gzopen() or gzdopen(), and before any other calls that read or write the
1337 file. The buffer memory allocation is always deferred to the first read or
1338 write. Three times that size in buffer space is allocated. A larger buffer
1339 size of, for example, 64K or 128K bytes will noticeably increase the speed
1340 of decompression (reading).
1341
1342 The new buffer size also affects the maximum length for gzprintf().
1343
1344 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1345 too late.
1346*/
1347
1348ZEXTERN int ZEXPORT gzsetparams(gzFile file, int level, int strategy);
1349/*
1350 Dynamically update the compression level or strategy. See the description
1351 of deflateInit2 for the meaning of these parameters. Previously provided
1352 data is flushed before the parameter change.
1353
1354 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
1355 opened for writing, Z_ERRNO if there is an error writing the flushed data,
1356 or Z_MEM_ERROR if there is a memory allocation error.
1357*/
1358
1359ZEXTERN int ZEXPORT gzread(gzFile file, void *buf, unsigned len);
1360/*
1361 Reads the given number of uncompressed bytes from the compressed file. If
1362 the input file is not in gzip format, gzread copies the given number of
1363 bytes into the buffer directly from the file.
1364
1365 After reaching the end of a gzip stream in the input, gzread will continue
1366 to read, looking for another gzip stream. Any number of gzip streams may be
1367 concatenated in the input file, and will all be decompressed by gzread().
1368 If something other than a gzip stream is encountered after a gzip stream,
1369 that remaining trailing garbage is ignored (and no error is returned).
1370
1371 gzread can be used to read a gzip file that is being concurrently written.
1372 Upon reaching the end of the input, gzread will return with the available
1373 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1374 gzclearerr can be used to clear the end of file indicator in order to permit
1375 gzread to be tried again. Z_OK indicates that a gzip stream was completed
1376 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1377 middle of a gzip stream. Note that gzread does not return -1 in the event
1378 of an incomplete gzip stream. This error is deferred until gzclose(), which
1379 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1380 stream. Alternatively, gzerror can be used before gzclose to detect this
1381 case.
1382
1383 gzread returns the number of uncompressed bytes actually read, less than
1384 len for end of file, or -1 for error. If len is too large to fit in an int,
1385 then nothing is read, -1 is returned, and the error state is set to
1386 Z_STREAM_ERROR.
1387*/
1388
1389ZEXTERN size_t ZEXPORT gzfread (void *buf, size_t size, size_t nitems, gzFile file);
1390/*
1391 Read up to nitems items of size size from file to buf, otherwise operating
1392 as gzread() does. This duplicates the interface of stdio's fread(), with
1393 size_t request and return types.
1394
1395 gzfread() returns the number of full items read of size size, or zero if
1396 the end of the file was reached and a full item could not be read, or if
1397 there was an error. gzerror() must be consulted if zero is returned in
1398 order to determine if there was an error. If the multiplication of size and
1399 nitems overflows, i.e. the product does not fit in a size_t, then nothing
1400 is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
1401
1402 In the event that the end of file is reached and only a partial item is
1403 available at the end, i.e. the remaining uncompressed data length is not a
1404 multiple of size, then the final partial item is nevertheless read into buf
1405 and the end-of-file flag is set. The length of the partial item read is not
1406 provided, but could be inferred from the result of gztell(). This behavior
1407 is the same as the behavior of fread() implementations in common libraries,
1408 but it prevents the direct use of gzfread() to read a concurrently written
1409 file, reseting and retrying on end-of-file, when size is not 1.
1410*/
1411
1412ZEXTERN int ZEXPORT gzwrite(gzFile file, void const *buf, unsigned len);
1413/*
1414 Writes the given number of uncompressed bytes into the compressed file.
1415 gzwrite returns the number of uncompressed bytes written or 0 in case of
1416 error.
1417*/
1418
1419ZEXTERN size_t ZEXPORT gzfwrite(void const *buf, size_t size, size_t nitems, gzFile file);
1420/*
1421 gzfwrite() writes nitems items of size size from buf to file, duplicating
1422 the interface of stdio's fwrite(), with size_t request and return types.
1423
1424 gzfwrite() returns the number of full items written of size size, or zero
1425 if there was an error. If the multiplication of size and nitems overflows,
1426 i.e. the product does not fit in a size_t, then nothing is written, zero
1427 is returned, and the error state is set to Z_STREAM_ERROR.
1428*/
1429
1430ZEXTERN int ZEXPORTVA gzprintf(gzFile file, const char *format, ...);
1431/*
1432 Converts, formats, and writes the arguments to the compressed file under
1433 control of the format string, as in fprintf. gzprintf returns the number of
1434 uncompressed bytes actually written, or a negative zlib error code in case
1435 of error. The number of uncompressed bytes written is limited to 8191, or
1436 one less than the buffer size given to gzbuffer(). The caller should assure
1437 that this limit is not exceeded. If it is exceeded, then gzprintf() will
1438 return an error (0) with nothing written. In this case, there may also be a
1439 buffer overflow with unpredictable consequences, which is possible only if
1440 zlib was compiled with the insecure functions sprintf() or vsprintf()
1441 because the secure snprintf() or vsnprintf() functions were not available.
1442 This can be determined using zlibCompileFlags().
1443*/
1444
1445ZEXTERN int ZEXPORT gzputs(gzFile file, const char *s);
1446/*
1447 Writes the given null-terminated string to the compressed file, excluding
1448 the terminating null character.
1449
1450 gzputs returns the number of characters written, or -1 in case of error.
1451*/
1452
1453ZEXTERN char * ZEXPORT gzgets(gzFile file, char *buf, int len);
1454/*
1455 Reads bytes from the compressed file until len-1 characters are read, or a
1456 newline character is read and transferred to buf, or an end-of-file
1457 condition is encountered. If any characters are read or if len == 1, the
1458 string is terminated with a null character. If no characters are read due
1459 to an end-of-file or len < 1, then the buffer is left untouched.
1460
1461 gzgets returns buf which is a null-terminated string, or it returns NULL
1462 for end-of-file or in case of error. If there was an error, the contents at
1463 buf are indeterminate.
1464*/
1465
1466ZEXTERN int ZEXPORT gzputc(gzFile file, int c);
1467/*
1468 Writes c, converted to an unsigned char, into the compressed file. gzputc
1469 returns the value that was written, or -1 in case of error.
1470*/
1471
1472ZEXTERN int ZEXPORT gzgetc(gzFile file);
1473/*
1474 Reads one byte from the compressed file. gzgetc returns this byte or -1
1475 in case of end of file or error. This is implemented as a macro for speed.
1476 As such, it does not do all of the checking the other functions do. I.e.
1477 it does not check to see if file is NULL, nor whether the structure file
1478 points to has been clobbered or not.
1479*/
1480
1481ZEXTERN int ZEXPORT gzungetc(int c, gzFile file);
1482/*
1483 Push one character back onto the stream to be read as the first character
1484 on the next read. At least one character of push-back is allowed.
1485 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1486 fail if c is -1, and may fail if a character has been pushed but not read
1487 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1488 output buffer size of pushed characters is allowed. (See gzbuffer above.)
1489 The pushed character will be discarded if the stream is repositioned with
1490 gzseek() or gzrewind().
1491*/
1492
1493ZEXTERN int ZEXPORT gzflush(gzFile file, int flush);
1494/*
1495 Flushes all pending output into the compressed file. The parameter flush
1496 is as in the deflate() function. The return value is the zlib error number
1497 (see function gzerror below). gzflush is only permitted when writing.
1498
1499 If the flush parameter is Z_FINISH, the remaining data is written and the
1500 gzip stream is completed in the output. If gzwrite() is called again, a new
1501 gzip stream will be started in the output. gzread() is able to read such
1502 concatenated gzip streams.
1503
1504 gzflush should be called only when strictly necessary because it will
1505 degrade compression if called too often.
1506*/
1507
1508/*
1509ZEXTERN z_off_t ZEXPORT gzseek (gzFile file, z_off_t offset, int whence);
1510
1511 Sets the starting position for the next gzread or gzwrite on the given
1512 compressed file. The offset represents a number of bytes in the
1513 uncompressed data stream. The whence parameter is defined as in lseek(2);
1514 the value SEEK_END is not supported.
1515
1516 If the file is opened for reading, this function is emulated but can be
1517 extremely slow. If the file is opened for writing, only forward seeks are
1518 supported; gzseek then compresses a sequence of zeroes up to the new
1519 starting position.
1520
1521 gzseek returns the resulting offset location as measured in bytes from
1522 the beginning of the uncompressed stream, or -1 in case of error, in
1523 particular if the file is opened for writing and the new starting position
1524 would be before the current position.
1525*/
1526
1527ZEXTERN int ZEXPORT gzrewind(gzFile file);
1528/*
1529 Rewinds the given file. This function is supported only for reading.
1530
1531 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1532*/
1533
1534/*
1535ZEXTERN z_off_t ZEXPORT gztell(gzFile file);
1536
1537 Returns the starting position for the next gzread or gzwrite on the given
1538 compressed file. This position represents a number of bytes in the
1539 uncompressed data stream, and is zero when starting, even if appending or
1540 reading a gzip stream from the middle of a file using gzdopen().
1541
1542 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1543*/
1544
1545/*
1546ZEXTERN z_off_t ZEXPORT gzoffset(gzFile file);
1547
1548 Returns the current offset in the file being read or written. This offset
1549 includes the count of bytes that precede the gzip stream, for example when
1550 appending or when using gzdopen() for reading. When reading, the offset
1551 does not include as yet unused buffered input. This information can be used
1552 for a progress indicator. On error, gzoffset() returns -1.
1553*/
1554
1555ZEXTERN int ZEXPORT gzeof(gzFile file);
1556/*
1557 Returns true (1) if the end-of-file indicator has been set while reading,
1558 false (0) otherwise. Note that the end-of-file indicator is set only if the
1559 read tried to go past the end of the input, but came up short. Therefore,
1560 just like feof(), gzeof() may return false even if there is no more data to
1561 read, in the event that the last read request was for the exact number of
1562 bytes remaining in the input file. This will happen if the input file size
1563 is an exact multiple of the buffer size.
1564
1565 If gzeof() returns true, then the read functions will return no more data,
1566 unless the end-of-file indicator is reset by gzclearerr() and the input file
1567 has grown since the previous end of file was detected.
1568*/
1569
1570ZEXTERN int ZEXPORT gzdirect(gzFile file);
1571/*
1572 Returns true (1) if file is being copied directly while reading, or false
1573 (0) if file is a gzip stream being decompressed.
1574
1575 If the input file is empty, gzdirect() will return true, since the input
1576 does not contain a gzip stream.
1577
1578 If gzdirect() is used immediately after gzopen() or gzdopen() it will
1579 cause buffers to be allocated to allow reading the file to determine if it
1580 is a gzip file. Therefore if gzbuffer() is used, it should be called before
1581 gzdirect().
1582
1583 When writing, gzdirect() returns true (1) if transparent writing was
1584 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1585 gzdirect() is not needed when writing. Transparent writing must be
1586 explicitly requested, so the application already knows the answer. When
1587 linking statically, using gzdirect() will include all of the zlib code for
1588 gzip file reading and decompression, which may not be desired.)
1589*/
1590
1591ZEXTERN int ZEXPORT gzclose(gzFile file);
1592/*
1593 Flushes all pending output if necessary, closes the compressed file and
1594 deallocates the (de)compression state. Note that once file is closed, you
1595 cannot call gzerror with file, since its structures have been deallocated.
1596 gzclose must not be called more than once on the same file, just as free
1597 must not be called more than once on the same allocation.
1598
1599 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1600 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1601 last read ended in the middle of a gzip stream, or Z_OK on success.
1602*/
1603
1604ZEXTERN int ZEXPORT gzclose_r(gzFile file);
1605ZEXTERN int ZEXPORT gzclose_w(gzFile file);
1606/*
1607 Same as gzclose(), but gzclose_r() is only for use when reading, and
1608 gzclose_w() is only for use when writing or appending. The advantage to
1609 using these instead of gzclose() is that they avoid linking in zlib
1610 compression or decompression code that is not used when only reading or only
1611 writing respectively. If gzclose() is used, then both compression and
1612 decompression code will be included the application when linking to a static
1613 zlib library.
1614*/
1615
1616ZEXTERN const char * ZEXPORT gzerror(gzFile file, int *errnum);
1617/*
1618 Returns the error message for the last error which occurred on the given
1619 compressed file. errnum is set to zlib error number. If an error occurred
1620 in the file system and not in the compression library, errnum is set to
1621 Z_ERRNO and the application may consult errno to get the exact error code.
1622
1623 The application must not modify the returned string. Future calls to
1624 this function may invalidate the previously returned string. If file is
1625 closed, then the string previously returned by gzerror will no longer be
1626 available.
1627
1628 gzerror() should be used to distinguish errors from end-of-file for those
1629 functions above that do not distinguish those cases in their return values.
1630*/
1631
1632ZEXTERN void ZEXPORT gzclearerr(gzFile file);
1633/*
1634 Clears the error and end-of-file flags for file. This is analogous to the
1635 clearerr() function in stdio. This is useful for continuing to read a gzip
1636 file that is being written concurrently.
1637*/
1638
1639
1640 /* checksum functions */
1641
1642/*
1643 These functions are not related to compression but are exported
1644 anyway because they might be useful in applications using the compression
1645 library.
1646*/
1647
1648ZEXTERN uint32_t ZEXPORT adler32(uint32_t adler, const unsigned char *buf, uint32_t len);
1649/*
1650 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1651 return the updated checksum. If buf is NULL, this function returns the
1652 required initial value for the checksum.
1653
1654 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1655 much faster.
1656
1657 Usage example:
1658
1659 uint32_t adler = adler32(0L, NULL, 0);
1660
1661 while (read_buffer(buffer, length) != EOF) {
1662 adler = adler32(adler, buffer, length);
1663 }
1664 if (adler != original_adler) error();
1665*/
1666
1667ZEXTERN uint32_t ZEXPORT adler32_z (uint32_t adler, const unsigned char *buf, size_t len);
1668/*
1669 Same as adler32(), but with a size_t length.
1670*/
1671
1672/*
1673ZEXTERN uint32_t ZEXPORT adler32_combine(uint32_t adler1, uint32_t adler2, z_off_t len2);
1674
1675 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1676 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1677 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1678 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1679 that the z_off_t type (like off_t) is a signed integer. If len2 is
1680 negative, the result has no meaning or utility.
1681*/
1682
1683ZEXTERN unsigned long ZEXPORT crc32(unsigned long crc, const unsigned char *buf, unsigned int len);
1684/*
1685 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1686 updated CRC-32. If buf is NULL, this function returns the required
1687 initial value for the crc. Pre- and post-conditioning (one's complement) is
1688 performed within this function so it shouldn't be done by the application.
1689
1690 Usage example:
1691
1692 uint32_t crc = crc32(0L, NULL, 0);
1693
1694 while (read_buffer(buffer, length) != EOF) {
1695 crc = crc32(crc, buffer, length);
1696 }
1697 if (crc != original_crc) error();
1698*/
1699
1700ZEXTERN uint32_t ZEXPORT crc32_z (uint32_t crc, const unsigned char *buf, size_t len);
1701/*
1702 Same as crc32(), but with a size_t length.
1703*/
1704
1705/*
1706ZEXTERN uint32_t ZEXPORT crc32_combine(uint32_t crc1, uint32_t crc2, z_off64_t len2);
1707
1708 Combine two CRC-32 check values into one. For two sequences of bytes,
1709 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1710 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1711 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1712 len2.
1713*/
1714
1715/*
1716ZEXTERN void ZEXPORT crc32_combine_gen(uint32_t op[32], z_off_t len2);
1717
1718 Generate the operator op corresponding to length len2, to be used with
1719 crc32_combine_op(). op must have room for 32 z_crc_t values. (32 is the
1720 number of bits in the CRC.)
1721*/
1722
1723ZEXTERN uint32_t ZEXPORT crc32_combine_op(uint32_t crc1, uint32_t crc2,
1724 const uint32_t *op);
1725/*
1726 Give the same result as crc32_combine(), using op in place of len2. op is
1727 is generated from len2 by crc32_combine_gen(). This will be faster than
1728 crc32_combine() if the generated op is used many times.
1729*/
1730
1731
1732 /* various hacks, don't look :) */
1733
1734/* deflateInit and inflateInit are macros to allow checking the zlib version
1735 * and the compiler's view of z_stream:
1736 */
1737ZEXTERN int ZEXPORT deflateInit_(z_stream *strm, int level, const char *version, int stream_size);
1738ZEXTERN int ZEXPORT inflateInit_(z_stream *strm, const char *version, int stream_size);
1739ZEXTERN int ZEXPORT deflateInit2_(z_stream *strm, int level, int method, int windowBits, int memLevel,
1740 int strategy, const char *version, int stream_size);
1741ZEXTERN int ZEXPORT inflateInit2_(z_stream *strm, int windowBits, const char *version, int stream_size);
1742ZEXTERN int ZEXPORT inflateBackInit_(z_stream *strm, int windowBits, unsigned char *window,
1743 const char *version, int stream_size);
1744#define deflateInit(strm, level) deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1745#define inflateInit(strm) inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1746#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1747 deflateInit2_((strm), (level), (method), (windowBits), (memLevel), \
1748 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1749#define inflateInit2(strm, windowBits) inflateInit2_((strm), (windowBits), ZLIB_VERSION, (int)sizeof(z_stream))
1750#define inflateBackInit(strm, windowBits, window) \
1751 inflateBackInit_((strm), (windowBits), (window), ZLIB_VERSION, (int)sizeof(z_stream))
1752
1753
1754/* gzgetc() macro and its supporting function and exposed data structure. Note
1755 * that the real internal state is much larger than the exposed structure.
1756 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1757 * user should not mess with these exposed elements, since their names or
1758 * behavior could change in the future, perhaps even capriciously. They can
1759 * only be used by the gzgetc() macro. You have been warned.
1760 */
1761struct gzFile_s {
1762 unsigned have;
1763 unsigned char *next;
1764 z_off64_t pos;
1765};
1766ZEXTERN int ZEXPORT gzgetc_(gzFile file); /* backward compatibility */
1767# define gzgetc(g) ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1768
1769/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1770 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1771 * both are true, the application gets the *64 functions, and the regular
1772 * functions are changed to 64 bits) -- in case these are set on systems
1773 * without large file support, _LFS64_LARGEFILE must also be true
1774 */
1775#ifdef Z_LARGE64
1776 ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *);
1777 ZEXTERN z_off64_t ZEXPORT gzseek64(gzFile, z_off64_t, int);
1778 ZEXTERN z_off64_t ZEXPORT gztell64(gzFile);
1779 ZEXTERN z_off64_t ZEXPORT gzoffset64(gzFile);
1780#endif
1781
1782#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1783# define gzopen gzopen64
1784# define gzseek gzseek64
1785# define gztell gztell64
1786# define gzoffset gzoffset64
1787# ifndef Z_LARGE64
1788 ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *);
1789 ZEXTERN z_off_t ZEXPORT gzseek64(gzFile, z_off_t, int);
1790 ZEXTERN z_off_t ZEXPORT gztell64(gzFile);
1791 ZEXTERN z_off_t ZEXPORT gzoffset64(gzFile);
1792# endif
1793#else
1794 ZEXTERN gzFile ZEXPORT gzopen(const char *, const char *);
1795 ZEXTERN z_off_t ZEXPORT gzseek(gzFile, z_off_t, int);
1796 ZEXTERN z_off_t ZEXPORT gztell(gzFile);
1797 ZEXTERN z_off_t ZEXPORT gzoffset(gzFile);
1798#endif
1799
1800
1801/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1802 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1803 * both are true, the application gets the *64 functions, and the regular
1804 * functions are changed to 64 bits) -- in case these are set on systems
1805 * without large file support, _LFS64_LARGEFILE must also be true
1806 */
1807#ifdef Z_LARGE64
1808 ZEXTERN uint32_t ZEXPORT adler32_combine64(uint32_t, uint32_t, z_off64_t);
1809 ZEXTERN uint32_t ZEXPORT crc32_combine64(uint32_t, uint32_t, z_off64_t);
1810 ZEXTERN void ZEXPORT crc32_combine_gen64(uint32_t *op, z_off64_t);
1811#endif
1812
1813#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1814# define adler32_combine adler32_combine64
1815# define crc32_combine crc32_combine64
1816# define crc32_combine_gen crc32_combine_gen64
1817# ifndef Z_LARGE64
1818 ZEXTERN uint32_t ZEXPORT adler32_combine64(uint32_t, uint32_t, z_off_t);
1819 ZEXTERN uint32_t ZEXPORT crc32_combine64(uint32_t, uint32_t, z_off_t);
1820 ZEXTERN void ZEXPORT crc32_combine_gen64(uint32_t *op, z_off64_t);
1821# endif
1822#else
1823 ZEXTERN uint32_t ZEXPORT adler32_combine(uint32_t, uint32_t, z_off_t);
1824 ZEXTERN uint32_t ZEXPORT crc32_combine(uint32_t, uint32_t, z_off_t);
1825 ZEXTERN void ZEXPORT crc32_combine_gen(uint32_t *op, z_off_t);
1826#endif
1827
1828
1829/* undocumented functions */
1830ZEXTERN const char * ZEXPORT zError (int);
1831ZEXTERN int ZEXPORT inflateSyncPoint (z_stream *);
1832ZEXTERN const uint32_t * ZEXPORT get_crc_table (void);
1833ZEXTERN int ZEXPORT inflateUndermine (z_stream *, int);
1834ZEXTERN int ZEXPORT inflateValidate (z_stream *, int);
1835ZEXTERN unsigned long ZEXPORT inflateCodesUsed (z_stream *);
1836ZEXTERN int ZEXPORT inflateResetKeep (z_stream *);
1837ZEXTERN int ZEXPORT deflateResetKeep (z_stream *);
1838
1839#if (defined(WIN32) || defined(__MINGW__))
1840 ZEXTERN gzFile ZEXPORT gzopen_w(const wchar_t *path, const char *mode);
1841#endif
1842ZEXTERN int ZEXPORTVA gzvprintf(gzFile file, const char *format, va_list va);
1843
1844#ifdef __cplusplus
1845}
1846#endif
1847
1848#endif /* ZLIB_H_ */
1849