1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.2.7, May 2nd, 2012
4 Copyright (C) 1995-2012 Jean-loup Gailly and Mark Adler
6 This software is provided 'as-is', without any express or implied
7 warranty. In no event will the authors be held liable for any damages
8 arising from the use of this software.
10 Permission is granted to anyone to use this software for any purpose,
11 including commercial applications, and to alter it and redistribute it
12 freely, subject to the following restrictions:
14 1. The origin of this software must not be misrepresented; you must not
15 claim that you wrote the original software. If you use this software
16 in a product, an acknowledgment in the product documentation would be
17 appreciated but is not required.
18 2. Altered source versions must be plainly marked as such, and must not be
19 misrepresented as being the original software.
20 3. This notice may not be removed or altered from any source distribution.
22 Jean-loup Gailly Mark Adler
23 jloup@gzip.org madler@alumni.caltech.edu
26 The data format used by the zlib library is described by RFCs (Request for
27 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
28 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
40 #define ZLIB_VERSION "1.2.7"
41 #define ZLIB_VERNUM 0x1270
42 #define ZLIB_VER_MAJOR 1
43 #define ZLIB_VER_MINOR 2
44 #define ZLIB_VER_REVISION 7
45 #define ZLIB_VER_SUBREVISION 0
48 The 'zlib' compression library provides in-memory compression and
49 decompression functions, including integrity checks of the uncompressed data.
50 This version of the library supports only one compression method (deflation)
51 but other algorithms will be added later and will have the same stream
54 Compression can be done in a single step if the buffers are large enough,
55 or can be done by repeated calls of the compression function. In the latter
56 case, the application must provide more input and/or consume the output
57 (providing more output space) before each call.
59 The compressed data format used by default by the in-memory functions is
60 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
61 around a deflate stream, which is itself documented in RFC 1951.
63 The library also supports reading and writing files in gzip (.gz) format
64 with an interface similar to that of stdio using the functions that start
65 with "gz". The gzip format is different from the zlib format. gzip is a
66 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
68 This library can optionally read and write gzip streams in memory as well.
70 The zlib format was designed to be compact and fast for use in memory
71 and on communications channels. The gzip format was designed for single-
72 file compression on file systems, has a larger header than zlib to maintain
73 directory information, and uses a different, slower check method than zlib.
75 The library does not install any signal handler. The decoder checks
76 the consistency of the compressed data, so the library should never crash
77 even in case of corrupted input.
80 typedef voidpf (*alloc_func
) OF((voidpf opaque
, uInt items
, uInt size
));
81 typedef void (*free_func
) OF((voidpf opaque
, voidpf address
));
83 struct internal_state
;
85 typedef struct z_stream_s
{
86 z_const Bytef
*next_in
; /* next input byte */
87 uInt avail_in
; /* number of bytes available at next_in */
88 uLong total_in
; /* total number of input bytes read so far */
90 Bytef
*next_out
; /* next output byte should be put there */
91 uInt avail_out
; /* remaining free space at next_out */
92 uLong total_out
; /* total number of bytes output so far */
94 z_const
char *msg
; /* last error message, NULL if no error */
95 struct internal_state FAR
*state
; /* not visible by applications */
97 alloc_func zalloc
; /* used to allocate the internal state */
98 free_func zfree
; /* used to free the internal state */
99 voidpf opaque
; /* private data object passed to zalloc and zfree */
101 int data_type
; /* best guess about the data type: binary or text */
102 uLong adler
; /* adler32 value of the uncompressed data */
103 uLong reserved
; /* reserved for future use */
106 typedef z_stream FAR
*z_streamp
;
109 gzip header information passed to and from zlib routines. See RFC 1952
110 for more details on the meanings of these fields.
112 typedef struct gz_header_s
{
113 int text
; /* true if compressed data believed to be text */
114 uLong time
; /* modification time */
115 int xflags
; /* extra flags (not used when writing a gzip file) */
116 int os
; /* operating system */
117 Bytef
*extra
; /* pointer to extra field or Z_NULL if none */
118 uInt extra_len
; /* extra field length (valid if extra != Z_NULL) */
119 uInt extra_max
; /* space at extra (only when reading header) */
120 Bytef
*name
; /* pointer to zero-terminated file name or Z_NULL */
121 uInt name_max
; /* space at name (only when reading header) */
122 Bytef
*comment
; /* pointer to zero-terminated comment or Z_NULL */
123 uInt comm_max
; /* space at comment (only when reading header) */
124 int hcrc
; /* true if there was or will be a header crc */
125 int done
; /* true when done reading gzip header (not used
126 when writing a gzip file) */
129 typedef gz_header FAR
*gz_headerp
;
132 The application must update next_in and avail_in when avail_in has dropped
133 to zero. It must update next_out and avail_out when avail_out has dropped
134 to zero. The application must initialize zalloc, zfree and opaque before
135 calling the init function. All other fields are set by the compression
136 library and must not be updated by the application.
138 The opaque value provided by the application will be passed as the first
139 parameter for calls of zalloc and zfree. This can be useful for custom
140 memory management. The compression library attaches no meaning to the
143 zalloc must return Z_NULL if there is not enough memory for the object.
144 If zlib is used in a multi-threaded application, zalloc and zfree must be
147 On 16-bit systems, the functions zalloc and zfree must be able to allocate
148 exactly 65536 bytes, but will not be required to allocate more than this if
149 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
150 returned by zalloc for objects of exactly 65536 bytes *must* have their
151 offset normalized to zero. The default allocation function provided by this
152 library ensures this (see zutil.c). To reduce memory requirements and avoid
153 any allocation of 64K objects, at the expense of compression ratio, compile
154 the library with -DMAX_WBITS=14 (see zconf.h).
156 The fields total_in and total_out can be used for statistics or progress
157 reports. After compression, total_in holds the total size of the
158 uncompressed data and may be saved for use in the decompressor (particularly
159 if the decompressor wants to decompress everything in a single step).
165 #define Z_PARTIAL_FLUSH 1
166 #define Z_SYNC_FLUSH 2
167 #define Z_FULL_FLUSH 3
171 /* Allowed flush values; see deflate() and inflate() below for details */
174 #define Z_STREAM_END 1
175 #define Z_NEED_DICT 2
177 #define Z_STREAM_ERROR (-2)
178 #define Z_DATA_ERROR (-3)
179 #define Z_MEM_ERROR (-4)
180 #define Z_BUF_ERROR (-5)
181 #define Z_VERSION_ERROR (-6)
182 /* Return codes for the compression/decompression functions. Negative values
183 * are errors, positive values are used for special but normal events.
186 #define Z_NO_COMPRESSION 0
187 #define Z_BEST_SPEED 1
188 #define Z_BEST_COMPRESSION 9
189 #define Z_DEFAULT_COMPRESSION (-1)
190 /* compression levels */
193 #define Z_HUFFMAN_ONLY 2
196 #define Z_DEFAULT_STRATEGY 0
197 /* compression strategy; see deflateInit2() below for details */
201 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
203 /* Possible values of the data_type field (though see inflate()) */
206 /* The deflate compression method (the only one supported in this version) */
208 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
210 #define zlib_version zlibVersion()
211 /* for compatibility with versions < 1.0.2 */
214 /* basic functions */
216 ZEXTERN
const char * ZEXPORT zlibVersion
OF((void));
217 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
218 If the first character differs, the library code actually used is not
219 compatible with the zlib.h header file used by the application. This check
220 is automatically made by deflateInit and inflateInit.
224 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
226 Initializes the internal stream state for compression. The fields
227 zalloc, zfree and opaque must be initialized before by the caller. If
228 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
229 allocation functions.
231 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
232 1 gives best speed, 9 gives best compression, 0 gives no compression at all
233 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
234 requests a default compromise between speed and compression (currently
235 equivalent to level 6).
237 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
238 memory, Z_STREAM_ERROR if level is not a valid compression level, or
239 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
240 with the version assumed by the caller (ZLIB_VERSION). msg is set to null
241 if there is no error message. deflateInit does not perform any compression:
242 this will be done by deflate().
246 ZEXTERN
int ZEXPORT deflate
OF((z_streamp strm
, int flush
));
248 deflate compresses as much data as possible, and stops when the input
249 buffer becomes empty or the output buffer becomes full. It may introduce
250 some output latency (reading input without producing any output) except when
253 The detailed semantics are as follows. deflate performs one or both of the
256 - Compress more input starting at next_in and update next_in and avail_in
257 accordingly. If not all input can be processed (because there is not
258 enough room in the output buffer), next_in and avail_in are updated and
259 processing will resume at this point for the next call of deflate().
261 - Provide more output starting at next_out and update next_out and avail_out
262 accordingly. This action is forced if the parameter flush is non zero.
263 Forcing flush frequently degrades the compression ratio, so this parameter
264 should be set only when necessary (in interactive applications). Some
265 output may be provided even if flush is not set.
267 Before the call of deflate(), the application should ensure that at least
268 one of the actions is possible, by providing more input and/or consuming more
269 output, and updating avail_in or avail_out accordingly; avail_out should
270 never be zero before the call. The application can consume the compressed
271 output when it wants, for example when the output buffer is full (avail_out
272 == 0), or after each call of deflate(). If deflate returns Z_OK and with
273 zero avail_out, it must be called again after making room in the output
274 buffer because there might be more output pending.
276 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
277 decide how much data to accumulate before producing output, in order to
278 maximize compression.
280 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
281 flushed to the output buffer and the output is aligned on a byte boundary, so
282 that the decompressor can get all input data available so far. (In
283 particular avail_in is zero after the call if enough output space has been
284 provided before the call.) Flushing may degrade compression for some
285 compression algorithms and so it should be used only when necessary. This
286 completes the current deflate block and follows it with an empty stored block
287 that is three bits plus filler bits to the next byte, followed by four bytes
290 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
291 output buffer, but the output is not aligned to a byte boundary. All of the
292 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
293 This completes the current deflate block and follows it with an empty fixed
294 codes block that is 10 bits long. This assures that enough bytes are output
295 in order for the decompressor to finish the block before the empty fixed code
298 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
299 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
300 seven bits of the current block are held to be written as the next byte after
301 the next deflate block is completed. In this case, the decompressor may not
302 be provided enough bits at this point in order to complete decompression of
303 the data provided so far to the compressor. It may need to wait for the next
304 block to be emitted. This is for advanced applications that need to control
305 the emission of deflate blocks.
307 If flush is set to Z_FULL_FLUSH, all output is flushed as with
308 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
309 restart from this point if previous compressed data has been damaged or if
310 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
313 If deflate returns with avail_out == 0, this function must be called again
314 with the same value of the flush parameter and more output space (updated
315 avail_out), until the flush is complete (deflate returns with non-zero
316 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
317 avail_out is greater than six to avoid repeated flush markers due to
318 avail_out == 0 on return.
320 If the parameter flush is set to Z_FINISH, pending input is processed,
321 pending output is flushed and deflate returns with Z_STREAM_END if there was
322 enough output space; if deflate returns with Z_OK, this function must be
323 called again with Z_FINISH and more output space (updated avail_out) but no
324 more input data, until it returns with Z_STREAM_END or an error. After
325 deflate has returned Z_STREAM_END, the only possible operations on the stream
326 are deflateReset or deflateEnd.
328 Z_FINISH can be used immediately after deflateInit if all the compression
329 is to be done in a single step. In this case, avail_out must be at least the
330 value returned by deflateBound (see below). Then deflate is guaranteed to
331 return Z_STREAM_END. If not enough output space is provided, deflate will
332 not return Z_STREAM_END, and it must be called again as described above.
334 deflate() sets strm->adler to the adler32 checksum of all input read
335 so far (that is, total_in bytes).
337 deflate() may update strm->data_type if it can make a good guess about
338 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
339 binary. This field is only for information purposes and does not affect the
340 compression algorithm in any manner.
342 deflate() returns Z_OK if some progress has been made (more input
343 processed or more output produced), Z_STREAM_END if all input has been
344 consumed and all output has been produced (only when flush is set to
345 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
346 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
347 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
348 fatal, and deflate() can be called again with more input and more output
349 space to continue compressing.
353 ZEXTERN
int ZEXPORT deflateEnd
OF((z_streamp strm
));
355 All dynamically allocated data structures for this stream are freed.
356 This function discards any unprocessed input and does not flush any pending
359 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
360 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
361 prematurely (some input or output was discarded). In the error case, msg
362 may be set but then points to a static string (which must not be
368 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
370 Initializes the internal stream state for decompression. The fields
371 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
372 the caller. If next_in is not Z_NULL and avail_in is large enough (the
373 exact value depends on the compression method), inflateInit determines the
374 compression method from the zlib header and allocates all data structures
375 accordingly; otherwise the allocation will be deferred to the first call of
376 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
377 use default allocation functions.
379 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
380 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
381 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
382 invalid, such as a null pointer to the structure. msg is set to null if
383 there is no error message. inflateInit does not perform any decompression
384 apart from possibly reading the zlib header if present: actual decompression
385 will be done by inflate(). (So next_in and avail_in may be modified, but
386 next_out and avail_out are unused and unchanged.) The current implementation
387 of inflateInit() does not process any header information -- that is deferred
388 until inflate() is called.
392 ZEXTERN
int ZEXPORT inflate
OF((z_streamp strm
, int flush
));
394 inflate decompresses as much data as possible, and stops when the input
395 buffer becomes empty or the output buffer becomes full. It may introduce
396 some output latency (reading input without producing any output) except when
399 The detailed semantics are as follows. inflate performs one or both of the
402 - Decompress more input starting at next_in and update next_in and avail_in
403 accordingly. If not all input can be processed (because there is not
404 enough room in the output buffer), next_in is updated and processing will
405 resume at this point for the next call of inflate().
407 - Provide more output starting at next_out and update next_out and avail_out
408 accordingly. inflate() provides as much output as possible, until there is
409 no more input data or no more space in the output buffer (see below about
410 the flush parameter).
412 Before the call of inflate(), the application should ensure that at least
413 one of the actions is possible, by providing more input and/or consuming more
414 output, and updating the next_* and avail_* values accordingly. The
415 application can consume the uncompressed output when it wants, for example
416 when the output buffer is full (avail_out == 0), or after each call of
417 inflate(). If inflate returns Z_OK and with zero avail_out, it must be
418 called again after making room in the output buffer because there might be
421 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
422 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
423 output as possible to the output buffer. Z_BLOCK requests that inflate()
424 stop if and when it gets to the next deflate block boundary. When decoding
425 the zlib or gzip format, this will cause inflate() to return immediately
426 after the header and before the first block. When doing a raw inflate,
427 inflate() will go ahead and process the first block, and will return when it
428 gets to the end of that block, or when it runs out of data.
430 The Z_BLOCK option assists in appending to or combining deflate streams.
431 Also to assist in this, on return inflate() will set strm->data_type to the
432 number of unused bits in the last byte taken from strm->next_in, plus 64 if
433 inflate() is currently decoding the last block in the deflate stream, plus
434 128 if inflate() returned immediately after decoding an end-of-block code or
435 decoding the complete header up to just before the first byte of the deflate
436 stream. The end-of-block will not be indicated until all of the uncompressed
437 data from that block has been written to strm->next_out. The number of
438 unused bits may in general be greater than seven, except when bit 7 of
439 data_type is set, in which case the number of unused bits will be less than
440 eight. data_type is set as noted here every time inflate() returns for all
441 flush options, and so can be used to determine the amount of currently
442 consumed input in bits.
444 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
445 end of each deflate block header is reached, before any actual data in that
446 block is decoded. This allows the caller to determine the length of the
447 deflate block header for later use in random access within a deflate block.
448 256 is added to the value of strm->data_type when inflate() returns
449 immediately after reaching the end of the deflate block header.
451 inflate() should normally be called until it returns Z_STREAM_END or an
452 error. However if all decompression is to be performed in a single step (a
453 single call of inflate), the parameter flush should be set to Z_FINISH. In
454 this case all pending input is processed and all pending output is flushed;
455 avail_out must be large enough to hold all of the uncompressed data for the
456 operation to complete. (The size of the uncompressed data may have been
457 saved by the compressor for this purpose.) The use of Z_FINISH is not
458 required to perform an inflation in one step. However it may be used to
459 inform inflate that a faster approach can be used for the single inflate()
460 call. Z_FINISH also informs inflate to not maintain a sliding window if the
461 stream completes, which reduces inflate's memory footprint. If the stream
462 does not complete, either because not all of the stream is provided or not
463 enough output space is provided, then a sliding window will be allocated and
464 inflate() can be called again to continue the operation as if Z_NO_FLUSH had
467 In this implementation, inflate() always flushes as much output as
468 possible to the output buffer, and always uses the faster approach on the
469 first call. So the effects of the flush parameter in this implementation are
470 on the return value of inflate() as noted below, when inflate() returns early
471 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
472 memory for a sliding window when Z_FINISH is used.
474 If a preset dictionary is needed after this call (see inflateSetDictionary
475 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
476 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
477 strm->adler to the Adler-32 checksum of all output produced so far (that is,
478 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
479 below. At the end of the stream, inflate() checks that its computed adler32
480 checksum is equal to that saved by the compressor and returns Z_STREAM_END
481 only if the checksum is correct.
483 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
484 deflate data. The header type is detected automatically, if requested when
485 initializing with inflateInit2(). Any information contained in the gzip
486 header is not retained, so applications that need that information should
487 instead use raw inflate, see inflateInit2() below, or inflateBack() and
488 perform their own processing of the gzip header and trailer. When processing
489 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
490 producted so far. The CRC-32 is checked against the gzip trailer.
492 inflate() returns Z_OK if some progress has been made (more input processed
493 or more output produced), Z_STREAM_END if the end of the compressed data has
494 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
495 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
496 corrupted (input stream not conforming to the zlib format or incorrect check
497 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
498 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
499 Z_BUF_ERROR if no progress is possible or if there was not enough room in the
500 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
501 inflate() can be called again with more input and more output space to
502 continue decompressing. If Z_DATA_ERROR is returned, the application may
503 then call inflateSync() to look for a good compression block if a partial
504 recovery of the data is desired.
508 ZEXTERN
int ZEXPORT inflateEnd
OF((z_streamp strm
));
510 All dynamically allocated data structures for this stream are freed.
511 This function discards any unprocessed input and does not flush any pending
514 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
515 was inconsistent. In the error case, msg may be set but then points to a
516 static string (which must not be deallocated).
520 /* Advanced functions */
523 The following functions are needed only in some special applications.
527 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
534 This is another version of deflateInit with more compression options. The
535 fields next_in, zalloc, zfree and opaque must be initialized before by the
538 The method parameter is the compression method. It must be Z_DEFLATED in
539 this version of the library.
541 The windowBits parameter is the base two logarithm of the window size
542 (the size of the history buffer). It should be in the range 8..15 for this
543 version of the library. Larger values of this parameter result in better
544 compression at the expense of memory usage. The default value is 15 if
545 deflateInit is used instead.
547 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
548 determines the window size. deflate() will then generate raw deflate data
549 with no zlib header or trailer, and will not compute an adler32 check value.
551 windowBits can also be greater than 15 for optional gzip encoding. Add
552 16 to windowBits to write a simple gzip header and trailer around the
553 compressed data instead of a zlib wrapper. The gzip header will have no
554 file name, no extra data, no comment, no modification time (set to zero), no
555 header crc, and the operating system will be set to 255 (unknown). If a
556 gzip stream is being written, strm->adler is a crc32 instead of an adler32.
558 The memLevel parameter specifies how much memory should be allocated
559 for the internal compression state. memLevel=1 uses minimum memory but is
560 slow and reduces compression ratio; memLevel=9 uses maximum memory for
561 optimal speed. The default value is 8. See zconf.h for total memory usage
562 as a function of windowBits and memLevel.
564 The strategy parameter is used to tune the compression algorithm. Use the
565 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
566 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
567 string match), or Z_RLE to limit match distances to one (run-length
568 encoding). Filtered data consists mostly of small values with a somewhat
569 random distribution. In this case, the compression algorithm is tuned to
570 compress them better. The effect of Z_FILTERED is to force more Huffman
571 coding and less string matching; it is somewhat intermediate between
572 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
573 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
574 strategy parameter only affects the compression ratio but not the
575 correctness of the compressed output even if it is not set appropriately.
576 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
577 decoder for special applications.
579 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
580 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
581 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
582 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
583 set to null if there is no error message. deflateInit2 does not perform any
584 compression: this will be done by deflate().
587 ZEXTERN
int ZEXPORT deflateSetDictionary
OF((z_streamp strm
,
588 const Bytef
*dictionary
,
591 Initializes the compression dictionary from the given byte sequence
592 without producing any compressed output. When using the zlib format, this
593 function must be called immediately after deflateInit, deflateInit2 or
594 deflateReset, and before any call of deflate. When doing raw deflate, this
595 function must be called either before any call of deflate, or immediately
596 after the completion of a deflate block, i.e. after all input has been
597 consumed and all output has been delivered when using any of the flush
598 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
599 compressor and decompressor must use exactly the same dictionary (see
600 inflateSetDictionary).
602 The dictionary should consist of strings (byte sequences) that are likely
603 to be encountered later in the data to be compressed, with the most commonly
604 used strings preferably put towards the end of the dictionary. Using a
605 dictionary is most useful when the data to be compressed is short and can be
606 predicted with good accuracy; the data can then be compressed better than
607 with the default empty dictionary.
609 Depending on the size of the compression data structures selected by
610 deflateInit or deflateInit2, a part of the dictionary may in effect be
611 discarded, for example if the dictionary is larger than the window size
612 provided in deflateInit or deflateInit2. Thus the strings most likely to be
613 useful should be put at the end of the dictionary, not at the front. In
614 addition, the current implementation of deflate will use at most the window
615 size minus 262 bytes of the provided dictionary.
617 Upon return of this function, strm->adler is set to the adler32 value
618 of the dictionary; the decompressor may later use this value to determine
619 which dictionary has been used by the compressor. (The adler32 value
620 applies to the whole dictionary even if only a subset of the dictionary is
621 actually used by the compressor.) If a raw deflate was requested, then the
622 adler32 value is not computed and strm->adler is not set.
624 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
625 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
626 inconsistent (for example if deflate has already been called for this stream
627 or if not at a block boundary for raw deflate). deflateSetDictionary does
628 not perform any compression: this will be done by deflate().
631 ZEXTERN
int ZEXPORT deflateCopy
OF((z_streamp dest
,
634 Sets the destination stream as a complete copy of the source stream.
636 This function can be useful when several compression strategies will be
637 tried, for example when there are several ways of pre-processing the input
638 data with a filter. The streams that will be discarded should then be freed
639 by calling deflateEnd. Note that deflateCopy duplicates the internal
640 compression state which can be quite large, so this strategy is slow and can
641 consume lots of memory.
643 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
644 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
645 (such as zalloc being Z_NULL). msg is left unchanged in both source and
649 ZEXTERN
int ZEXPORT deflateReset
OF((z_streamp strm
));
651 This function is equivalent to deflateEnd followed by deflateInit,
652 but does not free and reallocate all the internal compression state. The
653 stream will keep the same compression level and any other attributes that
654 may have been set by deflateInit2.
656 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
657 stream state was inconsistent (such as zalloc or state being Z_NULL).
660 ZEXTERN
int ZEXPORT deflateParams
OF((z_streamp strm
,
664 Dynamically update the compression level and compression strategy. The
665 interpretation of level and strategy is as in deflateInit2. This can be
666 used to switch between compression and straight copy of the input data, or
667 to switch to a different kind of input data requiring a different strategy.
668 If the compression level is changed, the input available so far is
669 compressed with the old level (and may be flushed); the new level will take
670 effect only at the next call of deflate().
672 Before the call of deflateParams, the stream state must be set as for
673 a call of deflate(), since the currently available input may have to be
674 compressed and flushed. In particular, strm->avail_out must be non-zero.
676 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
677 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
678 strm->avail_out was zero.
681 ZEXTERN
int ZEXPORT deflateTune
OF((z_streamp strm
,
687 Fine tune deflate's internal compression parameters. This should only be
688 used by someone who understands the algorithm used by zlib's deflate for
689 searching for the best matching string, and even then only by the most
690 fanatic optimizer trying to squeeze out the last compressed bit for their
691 specific input data. Read the deflate.c source code for the meaning of the
692 max_lazy, good_length, nice_length, and max_chain parameters.
694 deflateTune() can be called after deflateInit() or deflateInit2(), and
695 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
698 ZEXTERN uLong ZEXPORT deflateBound
OF((z_streamp strm
,
701 deflateBound() returns an upper bound on the compressed size after
702 deflation of sourceLen bytes. It must be called after deflateInit() or
703 deflateInit2(), and after deflateSetHeader(), if used. This would be used
704 to allocate an output buffer for deflation in a single pass, and so would be
705 called before deflate(). If that first deflate() call is provided the
706 sourceLen input bytes, an output buffer allocated to the size returned by
707 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
708 to return Z_STREAM_END. Note that it is possible for the compressed size to
709 be larger than the value returned by deflateBound() if flush options other
710 than Z_FINISH or Z_NO_FLUSH are used.
713 ZEXTERN
int ZEXPORT deflatePending
OF((z_streamp strm
,
717 deflatePending() returns the number of bytes and bits of output that have
718 been generated, but not yet provided in the available output. The bytes not
719 provided would be due to the available output space having being consumed.
720 The number of bits of output not provided are between 0 and 7, where they
721 await more bits to join them in order to fill out a full byte. If pending
722 or bits are Z_NULL, then those values are not set.
724 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
725 stream state was inconsistent.
728 ZEXTERN
int ZEXPORT deflatePrime
OF((z_streamp strm
,
732 deflatePrime() inserts bits in the deflate output stream. The intent
733 is that this function is used to start off the deflate output with the bits
734 leftover from a previous deflate stream when appending to it. As such, this
735 function can only be used for raw deflate, and must be used before the first
736 deflate() call after a deflateInit2() or deflateReset(). bits must be less
737 than or equal to 16, and that many of the least significant bits of value
738 will be inserted in the output.
740 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
741 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
742 source stream state was inconsistent.
745 ZEXTERN
int ZEXPORT deflateSetHeader
OF((z_streamp strm
,
748 deflateSetHeader() provides gzip header information for when a gzip
749 stream is requested by deflateInit2(). deflateSetHeader() may be called
750 after deflateInit2() or deflateReset() and before the first call of
751 deflate(). The text, time, os, extra field, name, and comment information
752 in the provided gz_header structure are written to the gzip header (xflag is
753 ignored -- the extra flags are set according to the compression level). The
754 caller must assure that, if not Z_NULL, name and comment are terminated with
755 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
756 available there. If hcrc is true, a gzip header crc is included. Note that
757 the current versions of the command-line version of gzip (up through version
758 1.3.x) do not support header crc's, and will report that it is a "multi-part
759 gzip file" and give up.
761 If deflateSetHeader is not used, the default gzip header has text false,
762 the time set to zero, and os set to 255, with no extra, name, or comment
763 fields. The gzip header is returned to the default state by deflateReset().
765 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
766 stream state was inconsistent.
770 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
773 This is another version of inflateInit with an extra parameter. The
774 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
775 before by the caller.
777 The windowBits parameter is the base two logarithm of the maximum window
778 size (the size of the history buffer). It should be in the range 8..15 for
779 this version of the library. The default value is 15 if inflateInit is used
780 instead. windowBits must be greater than or equal to the windowBits value
781 provided to deflateInit2() while compressing, or it must be equal to 15 if
782 deflateInit2() was not used. If a compressed stream with a larger window
783 size is given as input, inflate() will return with the error code
784 Z_DATA_ERROR instead of trying to allocate a larger window.
786 windowBits can also be zero to request that inflate use the window size in
787 the zlib header of the compressed stream.
789 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
790 determines the window size. inflate() will then process raw deflate data,
791 not looking for a zlib or gzip header, not generating a check value, and not
792 looking for any check values for comparison at the end of the stream. This
793 is for use with other formats that use the deflate compressed data format
794 such as zip. Those formats provide their own check values. If a custom
795 format is developed using the raw deflate format for compressed data, it is
796 recommended that a check value such as an adler32 or a crc32 be applied to
797 the uncompressed data as is done in the zlib, gzip, and zip formats. For
798 most applications, the zlib format should be used as is. Note that comments
799 above on the use in deflateInit2() applies to the magnitude of windowBits.
801 windowBits can also be greater than 15 for optional gzip decoding. Add
802 32 to windowBits to enable zlib and gzip decoding with automatic header
803 detection, or add 16 to decode only the gzip format (the zlib format will
804 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
805 crc32 instead of an adler32.
807 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
808 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
809 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
810 invalid, such as a null pointer to the structure. msg is set to null if
811 there is no error message. inflateInit2 does not perform any decompression
812 apart from possibly reading the zlib header if present: actual decompression
813 will be done by inflate(). (So next_in and avail_in may be modified, but
814 next_out and avail_out are unused and unchanged.) The current implementation
815 of inflateInit2() does not process any header information -- that is
816 deferred until inflate() is called.
819 ZEXTERN
int ZEXPORT inflateSetDictionary
OF((z_streamp strm
,
820 const Bytef
*dictionary
,
823 Initializes the decompression dictionary from the given uncompressed byte
824 sequence. This function must be called immediately after a call of inflate,
825 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
826 can be determined from the adler32 value returned by that call of inflate.
827 The compressor and decompressor must use exactly the same dictionary (see
828 deflateSetDictionary). For raw inflate, this function can be called at any
829 time to set the dictionary. If the provided dictionary is smaller than the
830 window and there is already data in the window, then the provided dictionary
831 will amend what's there. The application must insure that the dictionary
832 that was used for compression is provided.
834 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
835 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
836 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
837 expected one (incorrect adler32 value). inflateSetDictionary does not
838 perform any decompression: this will be done by subsequent calls of
842 ZEXTERN
int ZEXPORT inflateSync
OF((z_streamp strm
));
844 Skips invalid compressed data until a possible full flush point (see above
845 for the description of deflate with Z_FULL_FLUSH) can be found, or until all
846 available input is skipped. No output is provided.
848 inflateSync searches for a 00 00 FF FF pattern in the compressed data.
849 All full flush points have this pattern, but not all occurences of this
850 pattern are full flush points.
852 inflateSync returns Z_OK if a possible full flush point has been found,
853 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
854 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
855 In the success case, the application may save the current current value of
856 total_in which indicates where valid compressed data was found. In the
857 error case, the application may repeatedly call inflateSync, providing more
858 input each time, until success or end of the input data.
861 ZEXTERN
int ZEXPORT inflateCopy
OF((z_streamp dest
,
864 Sets the destination stream as a complete copy of the source stream.
866 This function can be useful when randomly accessing a large stream. The
867 first pass through the stream can periodically record the inflate state,
868 allowing restarting inflate at those points when randomly accessing the
871 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
872 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
873 (such as zalloc being Z_NULL). msg is left unchanged in both source and
877 ZEXTERN
int ZEXPORT inflateReset
OF((z_streamp strm
));
879 This function is equivalent to inflateEnd followed by inflateInit,
880 but does not free and reallocate all the internal decompression state. The
881 stream will keep attributes that may have been set by inflateInit2.
883 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
884 stream state was inconsistent (such as zalloc or state being Z_NULL).
887 ZEXTERN
int ZEXPORT inflateReset2
OF((z_streamp strm
,
890 This function is the same as inflateReset, but it also permits changing
891 the wrap and window size requests. The windowBits parameter is interpreted
892 the same as it is for inflateInit2.
894 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
895 stream state was inconsistent (such as zalloc or state being Z_NULL), or if
896 the windowBits parameter is invalid.
899 ZEXTERN
int ZEXPORT inflatePrime
OF((z_streamp strm
,
903 This function inserts bits in the inflate input stream. The intent is
904 that this function is used to start inflating at a bit position in the
905 middle of a byte. The provided bits will be used before any bytes are used
906 from next_in. This function should only be used with raw inflate, and
907 should be used before the first inflate() call after inflateInit2() or
908 inflateReset(). bits must be less than or equal to 16, and that many of the
909 least significant bits of value will be inserted in the input.
911 If bits is negative, then the input stream bit buffer is emptied. Then
912 inflatePrime() can be called again to put bits in the buffer. This is used
913 to clear out bits leftover after feeding inflate a block description prior
914 to feeding inflate codes.
916 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
917 stream state was inconsistent.
920 ZEXTERN
long ZEXPORT inflateMark
OF((z_streamp strm
));
922 This function returns two values, one in the lower 16 bits of the return
923 value, and the other in the remaining upper bits, obtained by shifting the
924 return value down 16 bits. If the upper value is -1 and the lower value is
925 zero, then inflate() is currently decoding information outside of a block.
926 If the upper value is -1 and the lower value is non-zero, then inflate is in
927 the middle of a stored block, with the lower value equaling the number of
928 bytes from the input remaining to copy. If the upper value is not -1, then
929 it is the number of bits back from the current bit position in the input of
930 the code (literal or length/distance pair) currently being processed. In
931 that case the lower value is the number of bytes already emitted for that
934 A code is being processed if inflate is waiting for more input to complete
935 decoding of the code, or if it has completed decoding but is waiting for
936 more output space to write the literal or match data.
938 inflateMark() is used to mark locations in the input data for random
939 access, which may be at bit positions, and to note those cases where the
940 output of a code may span boundaries of random access blocks. The current
941 location in the input stream can be determined from avail_in and data_type
942 as noted in the description for the Z_BLOCK flush parameter for inflate.
944 inflateMark returns the value noted above or -1 << 16 if the provided
945 source stream state was inconsistent.
948 ZEXTERN
int ZEXPORT inflateGetHeader
OF((z_streamp strm
,
951 inflateGetHeader() requests that gzip header information be stored in the
952 provided gz_header structure. inflateGetHeader() may be called after
953 inflateInit2() or inflateReset(), and before the first call of inflate().
954 As inflate() processes the gzip stream, head->done is zero until the header
955 is completed, at which time head->done is set to one. If a zlib stream is
956 being decoded, then head->done is set to -1 to indicate that there will be
957 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
958 used to force inflate() to return immediately after header processing is
959 complete and before any actual data is decompressed.
961 The text, time, xflags, and os fields are filled in with the gzip header
962 contents. hcrc is set to true if there is a header CRC. (The header CRC
963 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
964 contains the maximum number of bytes to write to extra. Once done is true,
965 extra_len contains the actual extra field length, and extra contains the
966 extra field, or that field truncated if extra_max is less than extra_len.
967 If name is not Z_NULL, then up to name_max characters are written there,
968 terminated with a zero unless the length is greater than name_max. If
969 comment is not Z_NULL, then up to comm_max characters are written there,
970 terminated with a zero unless the length is greater than comm_max. When any
971 of extra, name, or comment are not Z_NULL and the respective field is not
972 present in the header, then that field is set to Z_NULL to signal its
973 absence. This allows the use of deflateSetHeader() with the returned
974 structure to duplicate the header. However if those fields are set to
975 allocated memory, then the application will need to save those pointers
976 elsewhere so that they can be eventually freed.
978 If inflateGetHeader is not used, then the header information is simply
979 discarded. The header is always checked for validity, including the header
980 CRC if present. inflateReset() will reset the process to discard the header
981 information. The application would need to call inflateGetHeader() again to
982 retrieve the header from the next gzip stream.
984 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
985 stream state was inconsistent.
989 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
990 unsigned char FAR *window));
992 Initialize the internal stream state for decompression using inflateBack()
993 calls. The fields zalloc, zfree and opaque in strm must be initialized
994 before the call. If zalloc and zfree are Z_NULL, then the default library-
995 derived memory allocation routines are used. windowBits is the base two
996 logarithm of the window size, in the range 8..15. window is a caller
997 supplied buffer of that size. Except for special applications where it is
998 assured that deflate was used with small window sizes, windowBits must be 15
999 and a 32K byte window must be supplied to be able to decompress general
1002 See inflateBack() for the usage of these routines.
1004 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1005 the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1006 allocated, or Z_VERSION_ERROR if the version of the library does not match
1007 the version of the header file.
1010 typedef unsigned (*in_func
) OF((void FAR
*, const unsigned char FAR
* FAR
*));
1011 typedef int (*out_func
) OF((void FAR
*, unsigned char FAR
*, unsigned));
1013 ZEXTERN
int ZEXPORT inflateBack
OF((z_streamp strm
,
1014 in_func in
, void FAR
*in_desc
,
1015 out_func out
, void FAR
*out_desc
));
1017 inflateBack() does a raw inflate with a single call using a call-back
1018 interface for input and output. This is more efficient than inflate() for
1019 file i/o applications in that it avoids copying between the output and the
1020 sliding window by simply making the window itself the output buffer. This
1021 function trusts the application to not change the output buffer passed by
1022 the output function, at least until inflateBack() returns.
1024 inflateBackInit() must be called first to allocate the internal state
1025 and to initialize the state with the user-provided window buffer.
1026 inflateBack() may then be used multiple times to inflate a complete, raw
1027 deflate stream with each call. inflateBackEnd() is then called to free the
1030 A raw deflate stream is one with no zlib or gzip header or trailer.
1031 This routine would normally be used in a utility that reads zip or gzip
1032 files and writes out uncompressed files. The utility would decode the
1033 header and process the trailer on its own, hence this routine expects only
1034 the raw deflate stream to decompress. This is different from the normal
1035 behavior of inflate(), which expects either a zlib or gzip header and
1036 trailer around the deflate stream.
1038 inflateBack() uses two subroutines supplied by the caller that are then
1039 called by inflateBack() for input and output. inflateBack() calls those
1040 routines until it reads a complete deflate stream and writes out all of the
1041 uncompressed data, or until it encounters an error. The function's
1042 parameters and return types are defined above in the in_func and out_func
1043 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1044 number of bytes of provided input, and a pointer to that input in buf. If
1045 there is no input available, in() must return zero--buf is ignored in that
1046 case--and inflateBack() will return a buffer error. inflateBack() will call
1047 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
1048 should return zero on success, or non-zero on failure. If out() returns
1049 non-zero, inflateBack() will return with an error. Neither in() nor out()
1050 are permitted to change the contents of the window provided to
1051 inflateBackInit(), which is also the buffer that out() uses to write from.
1052 The length written by out() will be at most the window size. Any non-zero
1053 amount of input may be provided by in().
1055 For convenience, inflateBack() can be provided input on the first call by
1056 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1057 in() will be called. Therefore strm->next_in must be initialized before
1058 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1059 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1060 must also be initialized, and then if strm->avail_in is not zero, input will
1061 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1063 The in_desc and out_desc parameters of inflateBack() is passed as the
1064 first parameter of in() and out() respectively when they are called. These
1065 descriptors can be optionally used to pass any information that the caller-
1066 supplied in() and out() functions need to do their job.
1068 On return, inflateBack() will set strm->next_in and strm->avail_in to
1069 pass back any unused input that was provided by the last in() call. The
1070 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1071 if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1072 in the deflate stream (in which case strm->msg is set to indicate the nature
1073 of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1074 In the case of Z_BUF_ERROR, an input or output error can be distinguished
1075 using strm->next_in which will be Z_NULL only if in() returned an error. If
1076 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1077 non-zero. (in() will always be called before out(), so strm->next_in is
1078 assured to be defined if out() returns non-zero.) Note that inflateBack()
1082 ZEXTERN
int ZEXPORT inflateBackEnd
OF((z_streamp strm
));
1084 All memory allocated by inflateBackInit() is freed.
1086 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1087 state was inconsistent.
1090 ZEXTERN uLong ZEXPORT zlibCompileFlags
OF((void));
1091 /* Return flags indicating compile-time options.
1093 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1096 5.4: size of voidpf (pointer)
1097 7.6: size of z_off_t
1099 Compiler, assembler, and debug options:
1101 9: ASMV or ASMINF -- use ASM code
1102 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1105 One-time table building (smaller code, but not thread-safe if true):
1106 12: BUILDFIXED -- build static block decoding tables when needed
1107 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1110 Library content (indicates missing functionality):
1111 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1112 deflate code when not needed)
1113 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1114 and decode gzip streams (to avoid linking crc code)
1117 Operation variations (changes in library functionality):
1118 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1119 21: FASTEST -- deflate algorithm with only one, lowest compression level
1122 The sprintf variant used by gzprintf (zero is best):
1123 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1124 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1125 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1133 /* utility functions */
1136 The following utility functions are implemented on top of the basic
1137 stream-oriented functions. To simplify the interface, some default options
1138 are assumed (compression level and memory usage, standard memory allocation
1139 functions). The source code of these utility functions can be modified if
1140 you need special options.
1143 ZEXTERN
int ZEXPORT compress
OF((Bytef
*dest
, uLongf
*destLen
,
1144 const Bytef
*source
, uLong sourceLen
));
1146 Compresses the source buffer into the destination buffer. sourceLen is
1147 the byte length of the source buffer. Upon entry, destLen is the total size
1148 of the destination buffer, which must be at least the value returned by
1149 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1152 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1153 enough memory, Z_BUF_ERROR if there was not enough room in the output
1157 ZEXTERN
int ZEXPORT compress2
OF((Bytef
*dest
, uLongf
*destLen
,
1158 const Bytef
*source
, uLong sourceLen
,
1161 Compresses the source buffer into the destination buffer. The level
1162 parameter has the same meaning as in deflateInit. sourceLen is the byte
1163 length of the source buffer. Upon entry, destLen is the total size of the
1164 destination buffer, which must be at least the value returned by
1165 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1168 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1169 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1170 Z_STREAM_ERROR if the level parameter is invalid.
1173 ZEXTERN uLong ZEXPORT compressBound
OF((uLong sourceLen
));
1175 compressBound() returns an upper bound on the compressed size after
1176 compress() or compress2() on sourceLen bytes. It would be used before a
1177 compress() or compress2() call to allocate the destination buffer.
1180 ZEXTERN
int ZEXPORT uncompress
OF((Bytef
*dest
, uLongf
*destLen
,
1181 const Bytef
*source
, uLong sourceLen
));
1183 Decompresses the source buffer into the destination buffer. sourceLen is
1184 the byte length of the source buffer. Upon entry, destLen is the total size
1185 of the destination buffer, which must be large enough to hold the entire
1186 uncompressed data. (The size of the uncompressed data must have been saved
1187 previously by the compressor and transmitted to the decompressor by some
1188 mechanism outside the scope of this compression library.) Upon exit, destLen
1189 is the actual size of the uncompressed buffer.
1191 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1192 enough memory, Z_BUF_ERROR if there was not enough room in the output
1193 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1194 the case where there is not enough room, uncompress() will fill the output
1195 buffer with the uncompressed data up to that point.
1198 /* gzip file access functions */
1201 This library supports reading and writing files in gzip (.gz) format with
1202 an interface similar to that of stdio, using the functions that start with
1203 "gz". The gzip format is different from the zlib format. gzip is a gzip
1204 wrapper, documented in RFC 1952, wrapped around a deflate stream.
1207 typedef struct gzFile_s
*gzFile
; /* semi-opaque gzip file descriptor */
1210 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1212 Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1213 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1214 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1215 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1216 for fixed code compression as in "wb9F". (See the description of
1217 deflateInit2 for more information about the strategy parameter.) 'T' will
1218 request transparent writing or appending with no compression and not using
1221 "a" can be used instead of "w" to request that the gzip stream that will
1222 be written be appended to the file. "+" will result in an error, since
1223 reading and writing to the same gzip file is not supported. The addition of
1224 "x" when writing will create the file exclusively, which fails if the file
1225 already exists. On systems that support it, the addition of "e" when
1226 reading or writing will set the flag to close the file on an execve() call.
1228 These functions, as well as gzip, will read and decode a sequence of gzip
1229 streams in a file. The append function of gzopen() can be used to create
1230 such a file. (Also see gzflush() for another way to do this.) When
1231 appending, gzopen does not test whether the file begins with a gzip stream,
1232 nor does it look for the end of the gzip streams to begin appending. gzopen
1233 will simply append a gzip stream to the existing file.
1235 gzopen can be used to read a file which is not in gzip format; in this
1236 case gzread will directly read from the file without decompression. When
1237 reading, this will be detected automatically by looking for the magic two-
1240 gzopen returns NULL if the file could not be opened, if there was
1241 insufficient memory to allocate the gzFile state, or if an invalid mode was
1242 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1243 errno can be checked to determine if the reason gzopen failed was that the
1244 file could not be opened.
1247 ZEXTERN gzFile ZEXPORT gzdopen
OF((int fd
, const char *mode
));
1249 gzdopen associates a gzFile with the file descriptor fd. File descriptors
1250 are obtained from calls like open, dup, creat, pipe or fileno (if the file
1251 has been previously opened with fopen). The mode parameter is as in gzopen.
1253 The next call of gzclose on the returned gzFile will also close the file
1254 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1255 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1256 mode);. The duplicated descriptor should be saved to avoid a leak, since
1257 gzdopen does not close fd if it fails. If you are using fileno() to get the
1258 file descriptor from a FILE *, then you will have to use dup() to avoid
1259 double-close()ing the file descriptor. Both gzclose() and fclose() will
1260 close the associated file descriptor, so they need to have different file
1263 gzdopen returns NULL if there was insufficient memory to allocate the
1264 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1265 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1266 used until the next gz* read, write, seek, or close operation, so gzdopen
1267 will not detect if fd is invalid (unless fd is -1).
1270 ZEXTERN
int ZEXPORT gzbuffer
OF((gzFile file
, unsigned size
));
1272 Set the internal buffer size used by this library's functions. The
1273 default buffer size is 8192 bytes. This function must be called after
1274 gzopen() or gzdopen(), and before any other calls that read or write the
1275 file. The buffer memory allocation is always deferred to the first read or
1276 write. Two buffers are allocated, either both of the specified size when
1277 writing, or one of the specified size and the other twice that size when
1278 reading. A larger buffer size of, for example, 64K or 128K bytes will
1279 noticeably increase the speed of decompression (reading).
1281 The new buffer size also affects the maximum length for gzprintf().
1283 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1287 ZEXTERN
int ZEXPORT gzsetparams
OF((gzFile file
, int level
, int strategy
));
1289 Dynamically update the compression level or strategy. See the description
1290 of deflateInit2 for the meaning of these parameters.
1292 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1296 ZEXTERN
int ZEXPORT gzread
OF((gzFile file
, voidp buf
, unsigned len
));
1298 Reads the given number of uncompressed bytes from the compressed file. If
1299 the input file is not in gzip format, gzread copies the given number of
1300 bytes into the buffer directly from the file.
1302 After reaching the end of a gzip stream in the input, gzread will continue
1303 to read, looking for another gzip stream. Any number of gzip streams may be
1304 concatenated in the input file, and will all be decompressed by gzread().
1305 If something other than a gzip stream is encountered after a gzip stream,
1306 that remaining trailing garbage is ignored (and no error is returned).
1308 gzread can be used to read a gzip file that is being concurrently written.
1309 Upon reaching the end of the input, gzread will return with the available
1310 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1311 gzclearerr can be used to clear the end of file indicator in order to permit
1312 gzread to be tried again. Z_OK indicates that a gzip stream was completed
1313 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1314 middle of a gzip stream. Note that gzread does not return -1 in the event
1315 of an incomplete gzip stream. This error is deferred until gzclose(), which
1316 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1317 stream. Alternatively, gzerror can be used before gzclose to detect this
1320 gzread returns the number of uncompressed bytes actually read, less than
1321 len for end of file, or -1 for error.
1324 ZEXTERN
int ZEXPORT gzwrite
OF((gzFile file
,
1325 voidpc buf
, unsigned len
));
1327 Writes the given number of uncompressed bytes into the compressed file.
1328 gzwrite returns the number of uncompressed bytes written or 0 in case of
1332 ZEXTERN
int ZEXPORTVA gzprintf
Z_ARG((gzFile file
, const char *format
, ...));
1334 Converts, formats, and writes the arguments to the compressed file under
1335 control of the format string, as in fprintf. gzprintf returns the number of
1336 uncompressed bytes actually written, or 0 in case of error. The number of
1337 uncompressed bytes written is limited to 8191, or one less than the buffer
1338 size given to gzbuffer(). The caller should assure that this limit is not
1339 exceeded. If it is exceeded, then gzprintf() will return an error (0) with
1340 nothing written. In this case, there may also be a buffer overflow with
1341 unpredictable consequences, which is possible only if zlib was compiled with
1342 the insecure functions sprintf() or vsprintf() because the secure snprintf()
1343 or vsnprintf() functions were not available. This can be determined using
1347 ZEXTERN
int ZEXPORT gzputs
OF((gzFile file
, const char *s
));
1349 Writes the given null-terminated string to the compressed file, excluding
1350 the terminating null character.
1352 gzputs returns the number of characters written, or -1 in case of error.
1355 ZEXTERN
char * ZEXPORT gzgets
OF((gzFile file
, char *buf
, int len
));
1357 Reads bytes from the compressed file until len-1 characters are read, or a
1358 newline character is read and transferred to buf, or an end-of-file
1359 condition is encountered. If any characters are read or if len == 1, the
1360 string is terminated with a null character. If no characters are read due
1361 to an end-of-file or len < 1, then the buffer is left untouched.
1363 gzgets returns buf which is a null-terminated string, or it returns NULL
1364 for end-of-file or in case of error. If there was an error, the contents at
1365 buf are indeterminate.
1368 ZEXTERN
int ZEXPORT gzputc
OF((gzFile file
, int c
));
1370 Writes c, converted to an unsigned char, into the compressed file. gzputc
1371 returns the value that was written, or -1 in case of error.
1374 ZEXTERN
int ZEXPORT gzgetc
OF((gzFile file
));
1376 Reads one byte from the compressed file. gzgetc returns this byte or -1
1377 in case of end of file or error. This is implemented as a macro for speed.
1378 As such, it does not do all of the checking the other functions do. I.e.
1379 it does not check to see if file is NULL, nor whether the structure file
1380 points to has been clobbered or not.
1383 ZEXTERN
int ZEXPORT gzungetc
OF((int c
, gzFile file
));
1385 Push one character back onto the stream to be read as the first character
1386 on the next read. At least one character of push-back is allowed.
1387 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1388 fail if c is -1, and may fail if a character has been pushed but not read
1389 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1390 output buffer size of pushed characters is allowed. (See gzbuffer above.)
1391 The pushed character will be discarded if the stream is repositioned with
1392 gzseek() or gzrewind().
1395 ZEXTERN
int ZEXPORT gzflush
OF((gzFile file
, int flush
));
1397 Flushes all pending output into the compressed file. The parameter flush
1398 is as in the deflate() function. The return value is the zlib error number
1399 (see function gzerror below). gzflush is only permitted when writing.
1401 If the flush parameter is Z_FINISH, the remaining data is written and the
1402 gzip stream is completed in the output. If gzwrite() is called again, a new
1403 gzip stream will be started in the output. gzread() is able to read such
1404 concatented gzip streams.
1406 gzflush should be called only when strictly necessary because it will
1407 degrade compression if called too often.
1411 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1412 z_off_t offset, int whence));
1414 Sets the starting position for the next gzread or gzwrite on the given
1415 compressed file. The offset represents a number of bytes in the
1416 uncompressed data stream. The whence parameter is defined as in lseek(2);
1417 the value SEEK_END is not supported.
1419 If the file is opened for reading, this function is emulated but can be
1420 extremely slow. If the file is opened for writing, only forward seeks are
1421 supported; gzseek then compresses a sequence of zeroes up to the new
1424 gzseek returns the resulting offset location as measured in bytes from
1425 the beginning of the uncompressed stream, or -1 in case of error, in
1426 particular if the file is opened for writing and the new starting position
1427 would be before the current position.
1430 ZEXTERN
int ZEXPORT gzrewind
OF((gzFile file
));
1432 Rewinds the given file. This function is supported only for reading.
1434 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1438 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1440 Returns the starting position for the next gzread or gzwrite on the given
1441 compressed file. This position represents a number of bytes in the
1442 uncompressed data stream, and is zero when starting, even if appending or
1443 reading a gzip stream from the middle of a file using gzdopen().
1445 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1449 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1451 Returns the current offset in the file being read or written. This offset
1452 includes the count of bytes that precede the gzip stream, for example when
1453 appending or when using gzdopen() for reading. When reading, the offset
1454 does not include as yet unused buffered input. This information can be used
1455 for a progress indicator. On error, gzoffset() returns -1.
1458 ZEXTERN
int ZEXPORT gzeof
OF((gzFile file
));
1460 Returns true (1) if the end-of-file indicator has been set while reading,
1461 false (0) otherwise. Note that the end-of-file indicator is set only if the
1462 read tried to go past the end of the input, but came up short. Therefore,
1463 just like feof(), gzeof() may return false even if there is no more data to
1464 read, in the event that the last read request was for the exact number of
1465 bytes remaining in the input file. This will happen if the input file size
1466 is an exact multiple of the buffer size.
1468 If gzeof() returns true, then the read functions will return no more data,
1469 unless the end-of-file indicator is reset by gzclearerr() and the input file
1470 has grown since the previous end of file was detected.
1473 ZEXTERN
int ZEXPORT gzdirect
OF((gzFile file
));
1475 Returns true (1) if file is being copied directly while reading, or false
1476 (0) if file is a gzip stream being decompressed.
1478 If the input file is empty, gzdirect() will return true, since the input
1479 does not contain a gzip stream.
1481 If gzdirect() is used immediately after gzopen() or gzdopen() it will
1482 cause buffers to be allocated to allow reading the file to determine if it
1483 is a gzip file. Therefore if gzbuffer() is used, it should be called before
1486 When writing, gzdirect() returns true (1) if transparent writing was
1487 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1488 gzdirect() is not needed when writing. Transparent writing must be
1489 explicitly requested, so the application already knows the answer. When
1490 linking statically, using gzdirect() will include all of the zlib code for
1491 gzip file reading and decompression, which may not be desired.)
1494 ZEXTERN
int ZEXPORT gzclose
OF((gzFile file
));
1496 Flushes all pending output if necessary, closes the compressed file and
1497 deallocates the (de)compression state. Note that once file is closed, you
1498 cannot call gzerror with file, since its structures have been deallocated.
1499 gzclose must not be called more than once on the same file, just as free
1500 must not be called more than once on the same allocation.
1502 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1503 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1504 last read ended in the middle of a gzip stream, or Z_OK on success.
1507 ZEXTERN
int ZEXPORT gzclose_r
OF((gzFile file
));
1508 ZEXTERN
int ZEXPORT gzclose_w
OF((gzFile file
));
1510 Same as gzclose(), but gzclose_r() is only for use when reading, and
1511 gzclose_w() is only for use when writing or appending. The advantage to
1512 using these instead of gzclose() is that they avoid linking in zlib
1513 compression or decompression code that is not used when only reading or only
1514 writing respectively. If gzclose() is used, then both compression and
1515 decompression code will be included the application when linking to a static
1519 ZEXTERN
const char * ZEXPORT gzerror
OF((gzFile file
, int *errnum
));
1521 Returns the error message for the last error which occurred on the given
1522 compressed file. errnum is set to zlib error number. If an error occurred
1523 in the file system and not in the compression library, errnum is set to
1524 Z_ERRNO and the application may consult errno to get the exact error code.
1526 The application must not modify the returned string. Future calls to
1527 this function may invalidate the previously returned string. If file is
1528 closed, then the string previously returned by gzerror will no longer be
1531 gzerror() should be used to distinguish errors from end-of-file for those
1532 functions above that do not distinguish those cases in their return values.
1535 ZEXTERN
void ZEXPORT gzclearerr
OF((gzFile file
));
1537 Clears the error and end-of-file flags for file. This is analogous to the
1538 clearerr() function in stdio. This is useful for continuing to read a gzip
1539 file that is being written concurrently.
1542 #endif /* !Z_SOLO */
1544 /* checksum functions */
1547 These functions are not related to compression but are exported
1548 anyway because they might be useful in applications using the compression
1552 ZEXTERN uLong ZEXPORT adler32
OF((uLong adler
, const Bytef
*buf
, uInt len
));
1554 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1555 return the updated checksum. If buf is Z_NULL, this function returns the
1556 required initial value for the checksum.
1558 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1563 uLong adler = adler32(0L, Z_NULL, 0);
1565 while (read_buffer(buffer, length) != EOF) {
1566 adler = adler32(adler, buffer, length);
1568 if (adler != original_adler) error();
1572 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1575 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1576 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1577 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1578 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1579 that the z_off_t type (like off_t) is a signed integer. If len2 is
1580 negative, the result has no meaning or utility.
1583 ZEXTERN uLong ZEXPORT crc32
OF((uLong crc
, const Bytef
*buf
, uInt len
));
1585 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1586 updated CRC-32. If buf is Z_NULL, this function returns the required
1587 initial value for the crc. Pre- and post-conditioning (one's complement) is
1588 performed within this function so it shouldn't be done by the application.
1592 uLong crc = crc32(0L, Z_NULL, 0);
1594 while (read_buffer(buffer, length) != EOF) {
1595 crc = crc32(crc, buffer, length);
1597 if (crc != original_crc) error();
1601 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1603 Combine two CRC-32 check values into one. For two sequences of bytes,
1604 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1605 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1606 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1611 /* various hacks, don't look :) */
1613 /* deflateInit and inflateInit are macros to allow checking the zlib version
1614 * and the compiler's view of z_stream:
1616 ZEXTERN
int ZEXPORT deflateInit_
OF((z_streamp strm
, int level
,
1617 const char *version
, int stream_size
));
1618 ZEXTERN
int ZEXPORT inflateInit_
OF((z_streamp strm
,
1619 const char *version
, int stream_size
));
1620 ZEXTERN
int ZEXPORT deflateInit2_
OF((z_streamp strm
, int level
, int method
,
1621 int windowBits
, int memLevel
,
1622 int strategy
, const char *version
,
1624 ZEXTERN
int ZEXPORT inflateInit2_
OF((z_streamp strm
, int windowBits
,
1625 const char *version
, int stream_size
));
1626 ZEXTERN
int ZEXPORT inflateBackInit_
OF((z_streamp strm
, int windowBits
,
1627 unsigned char FAR
*window
,
1628 const char *version
,
1630 #define deflateInit(strm, level) \
1631 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1632 #define inflateInit(strm) \
1633 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1634 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1635 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1636 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1637 #define inflateInit2(strm, windowBits) \
1638 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1639 (int)sizeof(z_stream))
1640 #define inflateBackInit(strm, windowBits, window) \
1641 inflateBackInit_((strm), (windowBits), (window), \
1642 ZLIB_VERSION, (int)sizeof(z_stream))
1646 /* gzgetc() macro and its supporting function and exposed data structure. Note
1647 * that the real internal state is much larger than the exposed structure.
1648 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1649 * user should not mess with these exposed elements, since their names or
1650 * behavior could change in the future, perhaps even capriciously. They can
1651 * only be used by the gzgetc() macro. You have been warned.
1655 unsigned char *next
;
1658 ZEXTERN
int ZEXPORT gzgetc_
OF((gzFile file
)); /* backward compatibility */
1661 # define z_gzgetc(g) \
1662 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1664 # define gzgetc(g) \
1665 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1668 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1669 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1670 * both are true, the application gets the *64 functions, and the regular
1671 * functions are changed to 64 bits) -- in case these are set on systems
1672 * without large file support, _LFS64_LARGEFILE must also be true
1674 #if 0 /* XCSoar doesn't need large file support */
1676 ZEXTERN gzFile ZEXPORT gzopen64
OF((const char *, const char *));
1677 ZEXTERN z_off64_t ZEXPORT gzseek64
OF((gzFile
, z_off64_t
, int));
1678 ZEXTERN z_off64_t ZEXPORT gztell64
OF((gzFile
));
1679 ZEXTERN z_off64_t ZEXPORT gzoffset64
OF((gzFile
));
1680 ZEXTERN uLong ZEXPORT adler32_combine64
OF((uLong
, uLong
, z_off64_t
));
1681 ZEXTERN uLong ZEXPORT crc32_combine64
OF((uLong
, uLong
, z_off64_t
));
1685 /* XCSoar doesn't need large file support */
1686 #if 0 && !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1687 # ifdef Z_PREFIX_SET
1688 # define z_gzopen z_gzopen64
1689 # define z_gzseek z_gzseek64
1690 # define z_gztell z_gztell64
1691 # define z_gzoffset z_gzoffset64
1692 # define z_adler32_combine z_adler32_combine64
1693 # define z_crc32_combine z_crc32_combine64
1695 # define gzopen gzopen64
1696 # define gzseek gzseek64
1697 # define gztell gztell64
1698 # define gzoffset gzoffset64
1699 # define adler32_combine adler32_combine64
1700 # define crc32_combine crc32_combine64
1703 ZEXTERN gzFile ZEXPORT gzopen64
OF((const char *, const char *));
1704 ZEXTERN z_off_t ZEXPORT gzseek64
OF((gzFile
, z_off_t
, int));
1705 ZEXTERN z_off_t ZEXPORT gztell64
OF((gzFile
));
1706 ZEXTERN z_off_t ZEXPORT gzoffset64
OF((gzFile
));
1707 ZEXTERN uLong ZEXPORT adler32_combine64
OF((uLong
, uLong
, z_off_t
));
1708 ZEXTERN uLong ZEXPORT crc32_combine64
OF((uLong
, uLong
, z_off_t
));
1711 ZEXTERN gzFile ZEXPORT gzopen
OF((const char *, const char *));
1712 ZEXTERN z_off_t ZEXPORT gzseek
OF((gzFile
, z_off_t
, int));
1713 ZEXTERN z_off_t ZEXPORT gztell
OF((gzFile
));
1714 ZEXTERN z_off_t ZEXPORT gzoffset
OF((gzFile
));
1715 ZEXTERN uLong ZEXPORT adler32_combine
OF((uLong
, uLong
, z_off_t
));
1716 ZEXTERN uLong ZEXPORT crc32_combine
OF((uLong
, uLong
, z_off_t
));
1721 ZEXTERN uLong ZEXPORT adler32_combine
OF((uLong
, uLong
, z_off_t
));
1722 ZEXTERN uLong ZEXPORT crc32_combine
OF((uLong
, uLong
, z_off_t
));
1724 #endif /* !Z_SOLO */
1726 /* hack for buggy compilers */
1727 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1728 struct internal_state
{int dummy
;};
1731 /* undocumented functions */
1732 ZEXTERN
const char * ZEXPORT zError
OF((int));
1733 ZEXTERN
int ZEXPORT inflateSyncPoint
OF((z_streamp
));
1734 ZEXTERN
const z_crc_t FAR
* ZEXPORT get_crc_table
OF((void));
1735 ZEXTERN
int ZEXPORT inflateUndermine
OF((z_streamp
, int));
1736 ZEXTERN
int ZEXPORT inflateResetKeep
OF((z_streamp
));
1737 ZEXTERN
int ZEXPORT deflateResetKeep
OF((z_streamp
));
1738 #if defined(_WIN32) && !defined(Z_SOLO)
1739 ZEXTERN gzFile ZEXPORT gzopen_w
OF((const wchar_t *path
,