1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.2.8.1, May xxth, 2013
4 Copyright (C) 1995-2013 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 "1.2.8.1-motley"
41 #define ZLIB_VERNUM 0x1281
42 #define ZLIB_VER_MAJOR 1
43 #define ZLIB_VER_MINOR 2
44 #define ZLIB_VER_REVISION 8
45 #define ZLIB_VER_SUBREVISION 1
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 For the current implementation of deflate(), a windowBits value of 8 (a
548 window size of 256 bytes) is not supported. As a result, a request for 8
549 will result in 9 (a 512-byte window). In that case, providing 8 to
550 inflateInit2() will result in an error when the zlib header with 9 is
551 checked against the initialization of inflate(). The remedy is to not use 8
552 with deflateInit2() with this initialization, or at least in that case use 9
555 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
556 determines the window size. deflate() will then generate raw deflate data
557 with no zlib header or trailer, and will not compute an adler32 check value.
559 windowBits can also be greater than 15 for optional gzip encoding. Add
560 16 to windowBits to write a simple gzip header and trailer around the
561 compressed data instead of a zlib wrapper. The gzip header will have no
562 file name, no extra data, no comment, no modification time (set to zero), no
563 header crc, and the operating system will be set to 255 (unknown). If a
564 gzip stream is being written, strm->adler is a crc32 instead of an adler32.
566 For raw deflate or gzip encoding, a request for a 256-byte window is
567 rejected as invalid, since only the zlib header provides a means of
568 transmitting the window size to the decompressor.
570 The memLevel parameter specifies how much memory should be allocated
571 for the internal compression state. memLevel=1 uses minimum memory but is
572 slow and reduces compression ratio; memLevel=9 uses maximum memory for
573 optimal speed. The default value is 8. See zconf.h for total memory usage
574 as a function of windowBits and memLevel.
576 The strategy parameter is used to tune the compression algorithm. Use the
577 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
578 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
579 string match), or Z_RLE to limit match distances to one (run-length
580 encoding). Filtered data consists mostly of small values with a somewhat
581 random distribution. In this case, the compression algorithm is tuned to
582 compress them better. The effect of Z_FILTERED is to force more Huffman
583 coding and less string matching; it is somewhat intermediate between
584 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
585 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
586 strategy parameter only affects the compression ratio but not the
587 correctness of the compressed output even if it is not set appropriately.
588 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
589 decoder for special applications.
591 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
592 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
593 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
594 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
595 set to null if there is no error message. deflateInit2 does not perform any
596 compression: this will be done by deflate().
599 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
600 const Bytef *dictionary,
603 Initializes the compression dictionary from the given byte sequence
604 without producing any compressed output. When using the zlib format, this
605 function must be called immediately after deflateInit, deflateInit2 or
606 deflateReset, and before any call of deflate. When doing raw deflate, this
607 function must be called either before any call of deflate, or immediately
608 after the completion of a deflate block, i.e. after all input has been
609 consumed and all output has been delivered when using any of the flush
610 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
611 compressor and decompressor must use exactly the same dictionary (see
612 inflateSetDictionary).
614 The dictionary should consist of strings (byte sequences) that are likely
615 to be encountered later in the data to be compressed, with the most commonly
616 used strings preferably put towards the end of the dictionary. Using a
617 dictionary is most useful when the data to be compressed is short and can be
618 predicted with good accuracy; the data can then be compressed better than
619 with the default empty dictionary.
621 Depending on the size of the compression data structures selected by
622 deflateInit or deflateInit2, a part of the dictionary may in effect be
623 discarded, for example if the dictionary is larger than the window size
624 provided in deflateInit or deflateInit2. Thus the strings most likely to be
625 useful should be put at the end of the dictionary, not at the front. In
626 addition, the current implementation of deflate will use at most the window
627 size minus 262 bytes of the provided dictionary.
629 Upon return of this function, strm->adler is set to the adler32 value
630 of the dictionary; the decompressor may later use this value to determine
631 which dictionary has been used by the compressor. (The adler32 value
632 applies to the whole dictionary even if only a subset of the dictionary is
633 actually used by the compressor.) If a raw deflate was requested, then the
634 adler32 value is not computed and strm->adler is not set.
636 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
637 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
638 inconsistent (for example if deflate has already been called for this stream
639 or if not at a block boundary for raw deflate). deflateSetDictionary does
640 not perform any compression: this will be done by deflate().
643 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
646 Sets the destination stream as a complete copy of the source stream.
648 This function can be useful when several compression strategies will be
649 tried, for example when there are several ways of pre-processing the input
650 data with a filter. The streams that will be discarded should then be freed
651 by calling deflateEnd. Note that deflateCopy duplicates the internal
652 compression state which can be quite large, so this strategy is slow and can
653 consume lots of memory.
655 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
656 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
657 (such as zalloc being Z_NULL). msg is left unchanged in both source and
661 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
663 This function is equivalent to deflateEnd followed by deflateInit, but
664 does not free and reallocate the internal compression state. The stream
665 will leave the compression level and any other attributes that may have been
668 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
669 stream state was inconsistent (such as zalloc or state being Z_NULL).
672 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
676 Dynamically update the compression level and compression strategy. The
677 interpretation of level and strategy is as in deflateInit2(). This can be
678 used to switch between compression and straight copy of the input data, or
679 to switch to a different kind of input data requiring a different strategy.
680 If the compression approach (which is a function of the level) or the
681 strategy is changed, then the input available so far is compressed with the
682 old level and strategy using deflate(strm, Z_BLOCK). There are three
683 approaches for the compression levels 0, 1..3, and 4..9 respectively. The
684 new level and strategy will take effect at the next call of deflate().
686 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
687 not have enough output space to complete, then the parameter change will
688 take effect at an undetermined location in the uncompressed data provided so
689 far. In order to assure a change in the parameters at a specific location
690 in the uncompressed data, the deflate stream should first be flushed with
691 Z_BLOCK or another flush parameter, and deflate() called until
692 strm.avail_out is not zero, before the call of deflateParams(). Then no
693 more input data should be provided before the deflateParams() call. If this
694 is done, the old level and strategy will be applied to the data compressed
695 before deflateParams(), and the new level and strategy will be applied to
696 the the data compressed after deflateParams().
698 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source stream
699 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
700 there was not enough output space to complete the compression before the
701 parameters were changed. Note that in the case of a Z_BUF_ERROR, the
702 parameters are changed nevertheless, and will take effect at an undetermined
703 location in the previously supplied uncompressed data. Compression may
704 proceed after a Z_BUF_ERROR.
707 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
713 Fine tune deflate's internal compression parameters. This should only be
714 used by someone who understands the algorithm used by zlib's deflate for
715 searching for the best matching string, and even then only by the most
716 fanatic optimizer trying to squeeze out the last compressed bit for their
717 specific input data. Read the deflate.c source code for the meaning of the
718 max_lazy, good_length, nice_length, and max_chain parameters.
720 deflateTune() can be called after deflateInit() or deflateInit2(), and
721 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
724 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
727 deflateBound() returns an upper bound on the compressed size after
728 deflation of sourceLen bytes. It must be called after deflateInit() or
729 deflateInit2(), and after deflateSetHeader(), if used. This would be used
730 to allocate an output buffer for deflation in a single pass, and so would be
731 called before deflate(). If that first deflate() call is provided the
732 sourceLen input bytes, an output buffer allocated to the size returned by
733 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
734 to return Z_STREAM_END. Note that it is possible for the compressed size to
735 be larger than the value returned by deflateBound() if flush options other
736 than Z_FINISH or Z_NO_FLUSH are used.
739 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
743 deflatePending() returns the number of bytes and bits of output that have
744 been generated, but not yet provided in the available output. The bytes not
745 provided would be due to the available output space having being consumed.
746 The number of bits of output not provided are between 0 and 7, where they
747 await more bits to join them in order to fill out a full byte. If pending
748 or bits are Z_NULL, then those values are not set.
750 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
751 stream state was inconsistent.
754 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
758 deflatePrime() inserts bits in the deflate output stream. The intent
759 is that this function is used to start off the deflate output with the bits
760 leftover from a previous deflate stream when appending to it. As such, this
761 function can only be used for raw deflate, and must be used before the first
762 deflate() call after a deflateInit2() or deflateReset(). bits must be less
763 than or equal to 16, and that many of the least significant bits of value
764 will be inserted in the output.
766 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
767 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
768 source stream state was inconsistent.
771 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
774 deflateSetHeader() provides gzip header information for when a gzip
775 stream is requested by deflateInit2(). deflateSetHeader() may be called
776 after deflateInit2() or deflateReset() and before the first call of
777 deflate(). The text, time, os, extra field, name, and comment information
778 in the provided gz_header structure are written to the gzip header (xflag is
779 ignored -- the extra flags are set according to the compression level). The
780 caller must assure that, if not Z_NULL, name and comment are terminated with
781 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
782 available there. If hcrc is true, a gzip header crc is included. Note that
783 the current versions of the command-line version of gzip (up through version
784 1.3.x) do not support header crc's, and will report that it is a "multi-part
785 gzip file" and give up.
787 If deflateSetHeader is not used, the default gzip header has text false,
788 the time set to zero, and os set to 255, with no extra, name, or comment
789 fields. The gzip header is returned to the default state by deflateReset().
791 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
792 stream state was inconsistent.
796 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
799 This is another version of inflateInit with an extra parameter. The
800 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
801 before by the caller.
803 The windowBits parameter is the base two logarithm of the maximum window
804 size (the size of the history buffer). It should be in the range 8..15 for
805 this version of the library. The default value is 15 if inflateInit is used
806 instead. windowBits must be greater than or equal to the windowBits value
807 provided to deflateInit2() while compressing, or it must be equal to 15 if
808 deflateInit2() was not used. If a compressed stream with a larger window
809 size is given as input, inflate() will return with the error code
810 Z_DATA_ERROR instead of trying to allocate a larger window.
812 windowBits can also be zero to request that inflate use the window size in
813 the zlib header of the compressed stream.
815 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
816 determines the window size. inflate() will then process raw deflate data,
817 not looking for a zlib or gzip header, not generating a check value, and not
818 looking for any check values for comparison at the end of the stream. This
819 is for use with other formats that use the deflate compressed data format
820 such as zip. Those formats provide their own check values. If a custom
821 format is developed using the raw deflate format for compressed data, it is
822 recommended that a check value such as an adler32 or a crc32 be applied to
823 the uncompressed data as is done in the zlib, gzip, and zip formats. For
824 most applications, the zlib format should be used as is. Note that comments
825 above on the use in deflateInit2() applies to the magnitude of windowBits.
827 windowBits can also be greater than 15 for optional gzip decoding. Add
828 32 to windowBits to enable zlib and gzip decoding with automatic header
829 detection, or add 16 to decode only the gzip format (the zlib format will
830 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
831 crc32 instead of an adler32.
833 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
834 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
835 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
836 invalid, such as a null pointer to the structure. msg is set to null if
837 there is no error message. inflateInit2 does not perform any decompression
838 apart from possibly reading the zlib header if present: actual decompression
839 will be done by inflate(). (So next_in and avail_in may be modified, but
840 next_out and avail_out are unused and unchanged.) The current implementation
841 of inflateInit2() does not process any header information -- that is
842 deferred until inflate() is called.
845 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
846 const Bytef *dictionary,
849 Initializes the decompression dictionary from the given uncompressed byte
850 sequence. This function must be called immediately after a call of inflate,
851 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
852 can be determined from the adler32 value returned by that call of inflate.
853 The compressor and decompressor must use exactly the same dictionary (see
854 deflateSetDictionary). For raw inflate, this function can be called at any
855 time to set the dictionary. If the provided dictionary is smaller than the
856 window and there is already data in the window, then the provided dictionary
857 will amend what's there. The application must insure that the dictionary
858 that was used for compression is provided.
860 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
861 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
862 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
863 expected one (incorrect adler32 value). inflateSetDictionary does not
864 perform any decompression: this will be done by subsequent calls of
868 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
872 Returns the sliding dictionary being maintained by inflate. dictLength is
873 set to the number of bytes in the dictionary, and that many bytes are copied
874 to dictionary. dictionary must have enough space, where 32768 bytes is
875 always enough. If inflateGetDictionary() is called with dictionary equal to
876 Z_NULL, then only the dictionary length is returned, and nothing is copied.
877 Similary, if dictLength is Z_NULL, then it is not set.
879 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
880 stream state is inconsistent.
883 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
885 Skips invalid compressed data until a possible full flush point (see above
886 for the description of deflate with Z_FULL_FLUSH) can be found, or until all
887 available input is skipped. No output is provided.
889 inflateSync searches for a 00 00 FF FF pattern in the compressed data.
890 All full flush points have this pattern, but not all occurrences of this
891 pattern are full flush points.
893 inflateSync returns Z_OK if a possible full flush point has been found,
894 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
895 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
896 In the success case, the application may save the current current value of
897 total_in which indicates where valid compressed data was found. In the
898 error case, the application may repeatedly call inflateSync, providing more
899 input each time, until success or end of the input data.
902 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
905 Sets the destination stream as a complete copy of the source stream.
907 This function can be useful when randomly accessing a large stream. The
908 first pass through the stream can periodically record the inflate state,
909 allowing restarting inflate at those points when randomly accessing the
912 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
913 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
914 (such as zalloc being Z_NULL). msg is left unchanged in both source and
918 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
920 This function is equivalent to inflateEnd followed by inflateInit,
921 but does not free and reallocate all the internal decompression state. The
922 stream will keep attributes that may have been set by inflateInit2.
924 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
925 stream state was inconsistent (such as zalloc or state being Z_NULL).
928 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
931 This function is the same as inflateReset, but it also permits changing
932 the wrap and window size requests. The windowBits parameter is interpreted
933 the same as it is for inflateInit2.
935 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
936 stream state was inconsistent (such as zalloc or state being Z_NULL), or if
937 the windowBits parameter is invalid.
940 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
944 This function inserts bits in the inflate input stream. The intent is
945 that this function is used to start inflating at a bit position in the
946 middle of a byte. The provided bits will be used before any bytes are used
947 from next_in. This function should only be used with raw inflate, and
948 should be used before the first inflate() call after inflateInit2() or
949 inflateReset(). bits must be less than or equal to 16, and that many of the
950 least significant bits of value will be inserted in the input.
952 If bits is negative, then the input stream bit buffer is emptied. Then
953 inflatePrime() can be called again to put bits in the buffer. This is used
954 to clear out bits leftover after feeding inflate a block description prior
955 to feeding inflate codes.
957 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
958 stream state was inconsistent.
961 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
963 This function returns two values, one in the lower 16 bits of the return
964 value, and the other in the remaining upper bits, obtained by shifting the
965 return value down 16 bits. If the upper value is -1 and the lower value is
966 zero, then inflate() is currently decoding information outside of a block.
967 If the upper value is -1 and the lower value is non-zero, then inflate is in
968 the middle of a stored block, with the lower value equaling the number of
969 bytes from the input remaining to copy. If the upper value is not -1, then
970 it is the number of bits back from the current bit position in the input of
971 the code (literal or length/distance pair) currently being processed. In
972 that case the lower value is the number of bytes already emitted for that
975 A code is being processed if inflate is waiting for more input to complete
976 decoding of the code, or if it has completed decoding but is waiting for
977 more output space to write the literal or match data.
979 inflateMark() is used to mark locations in the input data for random
980 access, which may be at bit positions, and to note those cases where the
981 output of a code may span boundaries of random access blocks. The current
982 location in the input stream can be determined from avail_in and data_type
983 as noted in the description for the Z_BLOCK flush parameter for inflate.
985 inflateMark returns the value noted above or -65536 if the provided
986 source stream state was inconsistent.
989 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
992 inflateGetHeader() requests that gzip header information be stored in the
993 provided gz_header structure. inflateGetHeader() may be called after
994 inflateInit2() or inflateReset(), and before the first call of inflate().
995 As inflate() processes the gzip stream, head->done is zero until the header
996 is completed, at which time head->done is set to one. If a zlib stream is
997 being decoded, then head->done is set to -1 to indicate that there will be
998 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
999 used to force inflate() to return immediately after header processing is
1000 complete and before any actual data is decompressed.
1002 The text, time, xflags, and os fields are filled in with the gzip header
1003 contents. hcrc is set to true if there is a header CRC. (The header CRC
1004 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
1005 contains the maximum number of bytes to write to extra. Once done is true,
1006 extra_len contains the actual extra field length, and extra contains the
1007 extra field, or that field truncated if extra_max is less than extra_len.
1008 If name is not Z_NULL, then up to name_max characters are written there,
1009 terminated with a zero unless the length is greater than name_max. If
1010 comment is not Z_NULL, then up to comm_max characters are written there,
1011 terminated with a zero unless the length is greater than comm_max. When any
1012 of extra, name, or comment are not Z_NULL and the respective field is not
1013 present in the header, then that field is set to Z_NULL to signal its
1014 absence. This allows the use of deflateSetHeader() with the returned
1015 structure to duplicate the header. However if those fields are set to
1016 allocated memory, then the application will need to save those pointers
1017 elsewhere so that they can be eventually freed.
1019 If inflateGetHeader is not used, then the header information is simply
1020 discarded. The header is always checked for validity, including the header
1021 CRC if present. inflateReset() will reset the process to discard the header
1022 information. The application would need to call inflateGetHeader() again to
1023 retrieve the header from the next gzip stream.
1025 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1026 stream state was inconsistent.
1030 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1031 unsigned char FAR *window));
1033 Initialize the internal stream state for decompression using inflateBack()
1034 calls. The fields zalloc, zfree and opaque in strm must be initialized
1035 before the call. If zalloc and zfree are Z_NULL, then the default library-
1036 derived memory allocation routines are used. windowBits is the base two
1037 logarithm of the window size, in the range 8..15. window is a caller
1038 supplied buffer of that size. Except for special applications where it is
1039 assured that deflate was used with small window sizes, windowBits must be 15
1040 and a 32K byte window must be supplied to be able to decompress general
1043 See inflateBack() for the usage of these routines.
1045 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1046 the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1047 allocated, or Z_VERSION_ERROR if the version of the library does not match
1048 the version of the header file.
1051 typedef unsigned (*in_func) OF((void FAR *,
1052 z_const unsigned char FAR * FAR *));
1053 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1055 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1056 in_func in, void FAR *in_desc,
1057 out_func out, void FAR *out_desc));
1059 inflateBack() does a raw inflate with a single call using a call-back
1060 interface for input and output. This is potentially more efficient than
1061 inflate() for file i/o applications, in that it avoids copying between the
1062 output and the sliding window by simply making the window itself the output
1063 buffer. inflate() can be faster on modern CPUs when used with large
1064 buffers. inflateBack() trusts the application to not change the output
1065 buffer passed by the output function, at least until inflateBack() returns.
1067 inflateBackInit() must be called first to allocate the internal state
1068 and to initialize the state with the user-provided window buffer.
1069 inflateBack() may then be used multiple times to inflate a complete, raw
1070 deflate stream with each call. inflateBackEnd() is then called to free the
1073 A raw deflate stream is one with no zlib or gzip header or trailer.
1074 This routine would normally be used in a utility that reads zip or gzip
1075 files and writes out uncompressed files. The utility would decode the
1076 header and process the trailer on its own, hence this routine expects only
1077 the raw deflate stream to decompress. This is different from the normal
1078 behavior of inflate(), which expects either a zlib or gzip header and
1079 trailer around the deflate stream.
1081 inflateBack() uses two subroutines supplied by the caller that are then
1082 called by inflateBack() for input and output. inflateBack() calls those
1083 routines until it reads a complete deflate stream and writes out all of the
1084 uncompressed data, or until it encounters an error. The function's
1085 parameters and return types are defined above in the in_func and out_func
1086 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1087 number of bytes of provided input, and a pointer to that input in buf. If
1088 there is no input available, in() must return zero--buf is ignored in that
1089 case--and inflateBack() will return a buffer error. inflateBack() will call
1090 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
1091 should return zero on success, or non-zero on failure. If out() returns
1092 non-zero, inflateBack() will return with an error. Neither in() nor out()
1093 are permitted to change the contents of the window provided to
1094 inflateBackInit(), which is also the buffer that out() uses to write from.
1095 The length written by out() will be at most the window size. Any non-zero
1096 amount of input may be provided by in().
1098 For convenience, inflateBack() can be provided input on the first call by
1099 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1100 in() will be called. Therefore strm->next_in must be initialized before
1101 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1102 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1103 must also be initialized, and then if strm->avail_in is not zero, input will
1104 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1106 The in_desc and out_desc parameters of inflateBack() is passed as the
1107 first parameter of in() and out() respectively when they are called. These
1108 descriptors can be optionally used to pass any information that the caller-
1109 supplied in() and out() functions need to do their job.
1111 On return, inflateBack() will set strm->next_in and strm->avail_in to
1112 pass back any unused input that was provided by the last in() call. The
1113 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1114 if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1115 in the deflate stream (in which case strm->msg is set to indicate the nature
1116 of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1117 In the case of Z_BUF_ERROR, an input or output error can be distinguished
1118 using strm->next_in which will be Z_NULL only if in() returned an error. If
1119 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1120 non-zero. (in() will always be called before out(), so strm->next_in is
1121 assured to be defined if out() returns non-zero.) Note that inflateBack()
1125 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1127 All memory allocated by inflateBackInit() is freed.
1129 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1130 state was inconsistent.
1133 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1134 /* Return flags indicating compile-time options.
1136 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1139 5.4: size of voidpf (pointer)
1140 7.6: size of z_off_t
1142 Compiler, assembler, and debug options:
1144 9: ASMV or ASMINF -- use ASM code
1145 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1148 One-time table building (smaller code, but not thread-safe if true):
1149 12: BUILDFIXED -- build static block decoding tables when needed
1150 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1153 Library content (indicates missing functionality):
1154 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1155 deflate code when not needed)
1156 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1157 and decode gzip streams (to avoid linking crc code)
1160 Operation variations (changes in library functionality):
1161 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1162 21: FASTEST -- deflate algorithm with only one, lowest compression level
1165 The sprintf variant used by gzprintf (zero is best):
1166 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1167 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1168 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1176 /* utility functions */
1179 The following utility functions are implemented on top of the basic
1180 stream-oriented functions. To simplify the interface, some default options
1181 are assumed (compression level and memory usage, standard memory allocation
1182 functions). The source code of these utility functions can be modified if
1183 you need special options.
1186 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1187 const Bytef *source, uLong sourceLen));
1189 Compresses the source buffer into the destination buffer. sourceLen is
1190 the byte length of the source buffer. Upon entry, destLen is the total size
1191 of the destination buffer, which must be at least the value returned by
1192 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1193 compressed buffer. compress() is equivalent to compress2() with a level
1194 parameter of Z_DEFAULT_COMPRESSION.
1196 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1197 enough memory, Z_BUF_ERROR if there was not enough room in the output
1201 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1202 const Bytef *source, uLong sourceLen,
1205 Compresses the source buffer into the destination buffer. The level
1206 parameter has the same meaning as in deflateInit. sourceLen is the byte
1207 length of the source buffer. Upon entry, destLen is the total size of the
1208 destination buffer, which must be at least the value returned by
1209 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1212 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1213 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1214 Z_STREAM_ERROR if the level parameter is invalid.
1217 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1219 compressBound() returns an upper bound on the compressed size after
1220 compress() or compress2() on sourceLen bytes. It would be used before a
1221 compress() or compress2() call to allocate the destination buffer.
1224 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1225 const Bytef *source, uLong sourceLen));
1227 Decompresses the source buffer into the destination buffer. sourceLen is
1228 the byte length of the source buffer. Upon entry, destLen is the total size
1229 of the destination buffer, which must be large enough to hold the entire
1230 uncompressed data. (The size of the uncompressed data must have been saved
1231 previously by the compressor and transmitted to the decompressor by some
1232 mechanism outside the scope of this compression library.) Upon exit, destLen
1233 is the actual size of the uncompressed buffer.
1235 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1236 enough memory, Z_BUF_ERROR if there was not enough room in the output
1237 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1238 the case where there is not enough room, uncompress() will fill the output
1239 buffer with the uncompressed data up to that point.
1242 /* gzip file access functions */
1245 This library supports reading and writing files in gzip (.gz) format with
1246 an interface similar to that of stdio, using the functions that start with
1247 "gz". The gzip format is different from the zlib format. gzip is a gzip
1248 wrapper, documented in RFC 1952, wrapped around a deflate stream.
1251 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1254 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1256 Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1257 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1258 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1259 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1260 for fixed code compression as in "wb9F". (See the description of
1261 deflateInit2 for more information about the strategy parameter.) 'T' will
1262 request transparent writing or appending with no compression and not using
1265 "a" can be used instead of "w" to request that the gzip stream that will
1266 be written be appended to the file. "+" will result in an error, since
1267 reading and writing to the same gzip file is not supported. The addition of
1268 "x" when writing will create the file exclusively, which fails if the file
1269 already exists. On systems that support it, the addition of "e" when
1270 reading or writing will set the flag to close the file on an execve() call.
1272 These functions, as well as gzip, will read and decode a sequence of gzip
1273 streams in a file. The append function of gzopen() can be used to create
1274 such a file. (Also see gzflush() for another way to do this.) When
1275 appending, gzopen does not test whether the file begins with a gzip stream,
1276 nor does it look for the end of the gzip streams to begin appending. gzopen
1277 will simply append a gzip stream to the existing file.
1279 gzopen can be used to read a file which is not in gzip format; in this
1280 case gzread will directly read from the file without decompression. When
1281 reading, this will be detected automatically by looking for the magic two-
1284 gzopen returns NULL if the file could not be opened, if there was
1285 insufficient memory to allocate the gzFile state, or if an invalid mode was
1286 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1287 errno can be checked to determine if the reason gzopen failed was that the
1288 file could not be opened.
1291 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1293 gzdopen associates a gzFile with the file descriptor fd. File descriptors
1294 are obtained from calls like open, dup, creat, pipe or fileno (if the file
1295 has been previously opened with fopen). The mode parameter is as in gzopen.
1297 The next call of gzclose on the returned gzFile will also close the file
1298 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1299 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1300 mode);. The duplicated descriptor should be saved to avoid a leak, since
1301 gzdopen does not close fd if it fails. If you are using fileno() to get the
1302 file descriptor from a FILE *, then you will have to use dup() to avoid
1303 double-close()ing the file descriptor. Both gzclose() and fclose() will
1304 close the associated file descriptor, so they need to have different file
1307 gzdopen returns NULL if there was insufficient memory to allocate the
1308 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1309 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1310 used until the next gz* read, write, seek, or close operation, so gzdopen
1311 will not detect if fd is invalid (unless fd is -1).
1314 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1316 Set the internal buffer size used by this library's functions. The
1317 default buffer size is 8192 bytes. This function must be called after
1318 gzopen() or gzdopen(), and before any other calls that read or write the
1319 file. The buffer memory allocation is always deferred to the first read or
1320 write. Three times that size in buffer space is allocated. A larger buffer
1321 size of, for example, 64K or 128K bytes will noticeably increase the speed
1322 of decompression (reading).
1324 The new buffer size also affects the maximum length for gzprintf().
1326 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1330 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1332 Dynamically update the compression level or strategy. See the description
1333 of deflateInit2 for the meaning of these parameters.
1335 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1339 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1341 Reads the given number of uncompressed bytes from the compressed file. If
1342 the input file is not in gzip format, gzread copies the given number of
1343 bytes into the buffer directly from the file.
1345 After reaching the end of a gzip stream in the input, gzread will continue
1346 to read, looking for another gzip stream. Any number of gzip streams may be
1347 concatenated in the input file, and will all be decompressed by gzread().
1348 If something other than a gzip stream is encountered after a gzip stream,
1349 that remaining trailing garbage is ignored (and no error is returned).
1351 gzread can be used to read a gzip file that is being concurrently written.
1352 Upon reaching the end of the input, gzread will return with the available
1353 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1354 gzclearerr can be used to clear the end of file indicator in order to permit
1355 gzread to be tried again. Z_OK indicates that a gzip stream was completed
1356 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1357 middle of a gzip stream. Note that gzread does not return -1 in the event
1358 of an incomplete gzip stream. This error is deferred until gzclose(), which
1359 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1360 stream. Alternatively, gzerror can be used before gzclose to detect this
1363 gzread returns the number of uncompressed bytes actually read, less than
1364 len for end of file, or -1 for error.
1367 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1368 voidpc buf, unsigned len));
1370 Writes the given number of uncompressed bytes into the compressed file.
1371 gzwrite returns the number of uncompressed bytes written or 0 in case of
1375 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1377 Converts, formats, and writes the arguments to the compressed file under
1378 control of the format string, as in fprintf. gzprintf returns the number of
1379 uncompressed bytes actually written, or 0 in case of error. The number of
1380 uncompressed bytes written is limited to 8191, or one less than the buffer
1381 size given to gzbuffer(). The caller should assure that this limit is not
1382 exceeded. If it is exceeded, then gzprintf() will return an error (0) with
1383 nothing written. In this case, there may also be a buffer overflow with
1384 unpredictable consequences, which is possible only if zlib was compiled with
1385 the insecure functions sprintf() or vsprintf() because the secure snprintf()
1386 or vsnprintf() functions were not available. This can be determined using
1390 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1392 Writes the given null-terminated string to the compressed file, excluding
1393 the terminating null character.
1395 gzputs returns the number of characters written, or -1 in case of error.
1398 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1400 Reads bytes from the compressed file until len-1 characters are read, or a
1401 newline character is read and transferred to buf, or an end-of-file
1402 condition is encountered. If any characters are read or if len == 1, the
1403 string is terminated with a null character. If no characters are read due
1404 to an end-of-file or len < 1, then the buffer is left untouched.
1406 gzgets returns buf which is a null-terminated string, or it returns NULL
1407 for end-of-file or in case of error. If there was an error, the contents at
1408 buf are indeterminate.
1411 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1413 Writes c, converted to an unsigned char, into the compressed file. gzputc
1414 returns the value that was written, or -1 in case of error.
1417 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1419 Reads one byte from the compressed file. gzgetc returns this byte or -1
1420 in case of end of file or error. This is implemented as a macro for speed.
1421 As such, it does not do all of the checking the other functions do. I.e.
1422 it does not check to see if file is NULL, nor whether the structure file
1423 points to has been clobbered or not.
1426 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1428 Push one character back onto the stream to be read as the first character
1429 on the next read. At least one character of push-back is allowed.
1430 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1431 fail if c is -1, and may fail if a character has been pushed but not read
1432 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1433 output buffer size of pushed characters is allowed. (See gzbuffer above.)
1434 The pushed character will be discarded if the stream is repositioned with
1435 gzseek() or gzrewind().
1438 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1440 Flushes all pending output into the compressed file. The parameter flush
1441 is as in the deflate() function. The return value is the zlib error number
1442 (see function gzerror below). gzflush is only permitted when writing.
1444 If the flush parameter is Z_FINISH, the remaining data is written and the
1445 gzip stream is completed in the output. If gzwrite() is called again, a new
1446 gzip stream will be started in the output. gzread() is able to read such
1447 concatented gzip streams.
1449 gzflush should be called only when strictly necessary because it will
1450 degrade compression if called too often.
1454 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1455 z_off_t offset, int whence));
1457 Sets the starting position for the next gzread or gzwrite on the given
1458 compressed file. The offset represents a number of bytes in the
1459 uncompressed data stream. The whence parameter is defined as in lseek(2);
1460 the value SEEK_END is not supported.
1462 If the file is opened for reading, this function is emulated but can be
1463 extremely slow. If the file is opened for writing, only forward seeks are
1464 supported; gzseek then compresses a sequence of zeroes up to the new
1467 gzseek returns the resulting offset location as measured in bytes from
1468 the beginning of the uncompressed stream, or -1 in case of error, in
1469 particular if the file is opened for writing and the new starting position
1470 would be before the current position.
1473 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1475 Rewinds the given file. This function is supported only for reading.
1477 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1481 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1483 Returns the starting position for the next gzread or gzwrite on the given
1484 compressed file. This position represents a number of bytes in the
1485 uncompressed data stream, and is zero when starting, even if appending or
1486 reading a gzip stream from the middle of a file using gzdopen().
1488 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1492 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1494 Returns the current offset in the file being read or written. This offset
1495 includes the count of bytes that precede the gzip stream, for example when
1496 appending or when using gzdopen() for reading. When reading, the offset
1497 does not include as yet unused buffered input. This information can be used
1498 for a progress indicator. On error, gzoffset() returns -1.
1501 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1503 Returns true (1) if the end-of-file indicator has been set while reading,
1504 false (0) otherwise. Note that the end-of-file indicator is set only if the
1505 read tried to go past the end of the input, but came up short. Therefore,
1506 just like feof(), gzeof() may return false even if there is no more data to
1507 read, in the event that the last read request was for the exact number of
1508 bytes remaining in the input file. This will happen if the input file size
1509 is an exact multiple of the buffer size.
1511 If gzeof() returns true, then the read functions will return no more data,
1512 unless the end-of-file indicator is reset by gzclearerr() and the input file
1513 has grown since the previous end of file was detected.
1516 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1518 Returns true (1) if file is being copied directly while reading, or false
1519 (0) if file is a gzip stream being decompressed.
1521 If the input file is empty, gzdirect() will return true, since the input
1522 does not contain a gzip stream.
1524 If gzdirect() is used immediately after gzopen() or gzdopen() it will
1525 cause buffers to be allocated to allow reading the file to determine if it
1526 is a gzip file. Therefore if gzbuffer() is used, it should be called before
1529 When writing, gzdirect() returns true (1) if transparent writing was
1530 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1531 gzdirect() is not needed when writing. Transparent writing must be
1532 explicitly requested, so the application already knows the answer. When
1533 linking statically, using gzdirect() will include all of the zlib code for
1534 gzip file reading and decompression, which may not be desired.)
1537 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1539 Flushes all pending output if necessary, closes the compressed file and
1540 deallocates the (de)compression state. Note that once file is closed, you
1541 cannot call gzerror with file, since its structures have been deallocated.
1542 gzclose must not be called more than once on the same file, just as free
1543 must not be called more than once on the same allocation.
1545 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1546 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1547 last read ended in the middle of a gzip stream, or Z_OK on success.
1550 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1551 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1553 Same as gzclose(), but gzclose_r() is only for use when reading, and
1554 gzclose_w() is only for use when writing or appending. The advantage to
1555 using these instead of gzclose() is that they avoid linking in zlib
1556 compression or decompression code that is not used when only reading or only
1557 writing respectively. If gzclose() is used, then both compression and
1558 decompression code will be included the application when linking to a static
1562 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1564 Returns the error message for the last error which occurred on the given
1565 compressed file. errnum is set to zlib error number. If an error occurred
1566 in the file system and not in the compression library, errnum is set to
1567 Z_ERRNO and the application may consult errno to get the exact error code.
1569 The application must not modify the returned string. Future calls to
1570 this function may invalidate the previously returned string. If file is
1571 closed, then the string previously returned by gzerror will no longer be
1574 gzerror() should be used to distinguish errors from end-of-file for those
1575 functions above that do not distinguish those cases in their return values.
1578 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1580 Clears the error and end-of-file flags for file. This is analogous to the
1581 clearerr() function in stdio. This is useful for continuing to read a gzip
1582 file that is being written concurrently.
1585 #endif /* !Z_SOLO */
1587 /* checksum functions */
1590 These functions are not related to compression but are exported
1591 anyway because they might be useful in applications using the compression
1595 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1597 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1598 return the updated checksum. If buf is Z_NULL, this function returns the
1599 required initial value for the checksum.
1601 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1606 uLong adler = adler32(0L, Z_NULL, 0);
1608 while (read_buffer(buffer, length) != EOF) {
1609 adler = adler32(adler, buffer, length);
1611 if (adler != original_adler) error();
1615 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1618 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1619 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1620 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1621 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1622 that the z_off_t type (like off_t) is a signed integer. If len2 is
1623 negative, the result has no meaning or utility.
1626 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1628 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1629 updated CRC-32. If buf is Z_NULL, this function returns the required
1630 initial value for the crc. Pre- and post-conditioning (one's complement) is
1631 performed within this function so it shouldn't be done by the application.
1635 uLong crc = crc32(0L, Z_NULL, 0);
1637 while (read_buffer(buffer, length) != EOF) {
1638 crc = crc32(crc, buffer, length);
1640 if (crc != original_crc) error();
1644 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1646 Combine two CRC-32 check values into one. For two sequences of bytes,
1647 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1648 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1649 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1654 /* various hacks, don't look :) */
1656 /* deflateInit and inflateInit are macros to allow checking the zlib version
1657 * and the compiler's view of z_stream:
1659 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1660 const char *version, int stream_size));
1661 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1662 const char *version, int stream_size));
1663 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1664 int windowBits, int memLevel,
1665 int strategy, const char *version,
1667 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1668 const char *version, int stream_size));
1669 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1670 unsigned char FAR *window,
1671 const char *version,
1673 #define deflateInit(strm, level) \
1674 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1675 #define inflateInit(strm) \
1676 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1677 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1678 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1679 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1680 #define inflateInit2(strm, windowBits) \
1681 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1682 (int)sizeof(z_stream))
1683 #define inflateBackInit(strm, windowBits, window) \
1684 inflateBackInit_((strm), (windowBits), (window), \
1685 ZLIB_VERSION, (int)sizeof(z_stream))
1689 /* gzgetc() macro and its supporting function and exposed data structure. Note
1690 * that the real internal state is much larger than the exposed structure.
1691 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1692 * user should not mess with these exposed elements, since their names or
1693 * behavior could change in the future, perhaps even capriciously. They can
1694 * only be used by the gzgetc() macro. You have been warned.
1698 unsigned char *next;
1701 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
1704 # define z_gzgetc(g) \
1705 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1707 # define gzgetc(g) \
1708 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1711 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1712 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1713 * both are true, the application gets the *64 functions, and the regular
1714 * functions are changed to 64 bits) -- in case these are set on systems
1715 * without large file support, _LFS64_LARGEFILE must also be true
1718 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1719 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1720 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1721 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1722 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1723 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1726 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1727 # ifdef Z_PREFIX_SET
1728 # define z_gzopen z_gzopen64
1729 # define z_gzseek z_gzseek64
1730 # define z_gztell z_gztell64
1731 # define z_gzoffset z_gzoffset64
1732 # define z_adler32_combine z_adler32_combine64
1733 # define z_crc32_combine z_crc32_combine64
1735 # define gzopen gzopen64
1736 # define gzseek gzseek64
1737 # define gztell gztell64
1738 # define gzoffset gzoffset64
1739 # define adler32_combine adler32_combine64
1740 # define crc32_combine crc32_combine64
1743 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1744 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1745 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1746 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1747 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1748 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1751 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1752 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1753 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1754 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1755 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1756 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1761 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1762 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1764 #endif /* !Z_SOLO */
1766 /* undocumented functions */
1767 ZEXTERN const char * ZEXPORT zError OF((int));
1768 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1769 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1770 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1771 ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int));
1772 ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF ((z_streamp));
1773 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1774 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1775 #if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
1776 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1779 #if defined(STDC) || defined(Z_HAVE_STDARG_H)
1781 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,