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d4286ec4 1/* zlib.h -- interface of the 'zlib' general purpose compression library
1e1cf689 2 version 1.2.2, October 3rd, 2004
d4286ec4 3
1e1cf689 4 Copyright (C) 1995-2004 Jean-loup Gailly and Mark Adler
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5
6 This software is provided 'as-is', without any express or implied
7 warranty. In no event will the authors be held liable for any damages
8 arising from the use of this software.
9
10 Permission is granted to anyone to use this software for any purpose,
11 including commercial applications, and to alter it and redistribute it
12 freely, subject to the following restrictions:
13
14 1. The origin of this software must not be misrepresented; you must not
15 claim that you wrote the original software. If you use this software
16 in a product, an acknowledgment in the product documentation would be
17 appreciated but is not required.
18 2. Altered source versions must be plainly marked as such, and must not be
19 misrepresented as being the original software.
20 3. This notice may not be removed or altered from any source distribution.
21
22 Jean-loup Gailly Mark Adler
23 jloup@gzip.org madler@alumni.caltech.edu
24
25
26 The data format used by the zlib library is described by RFCs (Request for
1e1cf689 27 Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
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28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
29*/
30
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31#ifndef ZLIB_H
32#define ZLIB_H
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33
34#include "zconf.h"
35
36#ifdef __cplusplus
37extern "C" {
38#endif
39
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40#define ZLIB_VERSION "1.2.2"
41#define ZLIB_VERNUM 0x1220
d4286ec4 42
1e1cf689 43/*
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44 The 'zlib' compression library provides in-memory compression and
45 decompression functions, including integrity checks of the uncompressed
46 data. This version of the library supports only one compression method
47 (deflation) but other algorithms will be added later and will have the same
48 stream interface.
49
50 Compression can be done in a single step if the buffers are large
51 enough (for example if an input file is mmap'ed), or can be done by
52 repeated calls of the compression function. In the latter case, the
53 application must provide more input and/or consume the output
54 (providing more output space) before each call.
55
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56 The compressed data format used by default by the in-memory functions is
57 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
58 around a deflate stream, which is itself documented in RFC 1951.
59
d4286ec4 60 The library also supports reading and writing files in gzip (.gz) format
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61 with an interface similar to that of stdio using the functions that start
62 with "gz". The gzip format is different from the zlib format. gzip is a
63 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
64
65 This library can optionally read and write gzip streams in memory as well.
66
67 The zlib format was designed to be compact and fast for use in memory
68 and on communications channels. The gzip format was designed for single-
69 file compression on file systems, has a larger header than zlib to maintain
70 directory information, and uses a different, slower check method than zlib.
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71
72 The library does not install any signal handler. The decoder checks
73 the consistency of the compressed data, so the library should never
74 crash even in case of corrupted input.
75*/
76
77typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
78typedef void (*free_func) OF((voidpf opaque, voidpf address));
79
80struct internal_state;
81
82typedef struct z_stream_s {
83 Bytef *next_in; /* next input byte */
84 uInt avail_in; /* number of bytes available at next_in */
85 uLong total_in; /* total nb of input bytes read so far */
86
87 Bytef *next_out; /* next output byte should be put there */
88 uInt avail_out; /* remaining free space at next_out */
89 uLong total_out; /* total nb of bytes output so far */
90
91 char *msg; /* last error message, NULL if no error */
92 struct internal_state FAR *state; /* not visible by applications */
93
94 alloc_func zalloc; /* used to allocate the internal state */
95 free_func zfree; /* used to free the internal state */
96 voidpf opaque; /* private data object passed to zalloc and zfree */
97
98 int data_type; /* best guess about the data type: ascii or binary */
99 uLong adler; /* adler32 value of the uncompressed data */
100 uLong reserved; /* reserved for future use */
101} z_stream;
102
103typedef z_stream FAR *z_streamp;
104
105/*
106 The application must update next_in and avail_in when avail_in has
107 dropped to zero. It must update next_out and avail_out when avail_out
108 has dropped to zero. The application must initialize zalloc, zfree and
109 opaque before calling the init function. All other fields are set by the
110 compression library and must not be updated by the application.
111
112 The opaque value provided by the application will be passed as the first
113 parameter for calls of zalloc and zfree. This can be useful for custom
114 memory management. The compression library attaches no meaning to the
115 opaque value.
116
117 zalloc must return Z_NULL if there is not enough memory for the object.
118 If zlib is used in a multi-threaded application, zalloc and zfree must be
119 thread safe.
120
121 On 16-bit systems, the functions zalloc and zfree must be able to allocate
122 exactly 65536 bytes, but will not be required to allocate more than this
123 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
124 pointers returned by zalloc for objects of exactly 65536 bytes *must*
125 have their offset normalized to zero. The default allocation function
126 provided by this library ensures this (see zutil.c). To reduce memory
127 requirements and avoid any allocation of 64K objects, at the expense of
128 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
129
130 The fields total_in and total_out can be used for statistics or
131 progress reports. After compression, total_in holds the total size of
132 the uncompressed data and may be saved for use in the decompressor
133 (particularly if the decompressor wants to decompress everything in
134 a single step).
135*/
136
137 /* constants */
138
139#define Z_NO_FLUSH 0
140#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
141#define Z_SYNC_FLUSH 2
142#define Z_FULL_FLUSH 3
143#define Z_FINISH 4
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144#define Z_BLOCK 5
145/* Allowed flush values; see deflate() and inflate() below for details */
146#define Z_INSERT_ONLY 6
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147
148#define Z_OK 0
149#define Z_STREAM_END 1
150#define Z_NEED_DICT 2
151#define Z_ERRNO (-1)
152#define Z_STREAM_ERROR (-2)
153#define Z_DATA_ERROR (-3)
154#define Z_MEM_ERROR (-4)
155#define Z_BUF_ERROR (-5)
156#define Z_VERSION_ERROR (-6)
157/* Return codes for the compression/decompression functions. Negative
158 * values are errors, positive values are used for special but normal events.
159 */
160
161#define Z_NO_COMPRESSION 0
162#define Z_BEST_SPEED 1
163#define Z_BEST_COMPRESSION 9
164#define Z_DEFAULT_COMPRESSION (-1)
165/* compression levels */
166
167#define Z_FILTERED 1
168#define Z_HUFFMAN_ONLY 2
1e1cf689 169#define Z_RLE 3
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170#define Z_DEFAULT_STRATEGY 0
171/* compression strategy; see deflateInit2() below for details */
172
173#define Z_BINARY 0
174#define Z_ASCII 1
175#define Z_UNKNOWN 2
1e1cf689 176/* Possible values of the data_type field (though see inflate()) */
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177
178#define Z_DEFLATED 8
179/* The deflate compression method (the only one supported in this version) */
180
181#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
182
183#define zlib_version zlibVersion()
184/* for compatibility with versions < 1.0.2 */
185
186 /* basic functions */
187
06b91d8e 188ZEXTERN const char * ZEXPORT zlibVersion OF((void));
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189/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
190 If the first character differs, the library code actually used is
191 not compatible with the zlib.h header file used by the application.
192 This check is automatically made by deflateInit and inflateInit.
193 */
194
1e1cf689 195/*
06b91d8e 196ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
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197
198 Initializes the internal stream state for compression. The fields
199 zalloc, zfree and opaque must be initialized before by the caller.
200 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
201 use default allocation functions.
202
203 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
204 1 gives best speed, 9 gives best compression, 0 gives no compression at
205 all (the input data is simply copied a block at a time).
206 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
207 compression (currently equivalent to level 6).
208
209 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
210 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
211 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
212 with the version assumed by the caller (ZLIB_VERSION).
213 msg is set to null if there is no error message. deflateInit does not
214 perform any compression: this will be done by deflate().
215*/
216
217
06b91d8e 218ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
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219/*
220 deflate compresses as much data as possible, and stops when the input
221 buffer becomes empty or the output buffer becomes full. It may introduce some
222 output latency (reading input without producing any output) except when
223 forced to flush.
224
225 The detailed semantics are as follows. deflate performs one or both of the
226 following actions:
227
228 - Compress more input starting at next_in and update next_in and avail_in
229 accordingly. If not all input can be processed (because there is not
230 enough room in the output buffer), next_in and avail_in are updated and
231 processing will resume at this point for the next call of deflate().
232
233 - Provide more output starting at next_out and update next_out and avail_out
234 accordingly. This action is forced if the parameter flush is non zero.
235 Forcing flush frequently degrades the compression ratio, so this parameter
236 should be set only when necessary (in interactive applications).
237 Some output may be provided even if flush is not set.
238
239 Before the call of deflate(), the application should ensure that at least
240 one of the actions is possible, by providing more input and/or consuming
241 more output, and updating avail_in or avail_out accordingly; avail_out
242 should never be zero before the call. The application can consume the
243 compressed output when it wants, for example when the output buffer is full
244 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
245 and with zero avail_out, it must be called again after making room in the
246 output buffer because there might be more output pending.
247
248 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
249 flushed to the output buffer and the output is aligned on a byte boundary, so
250 that the decompressor can get all input data available so far. (In particular
251 avail_in is zero after the call if enough output space has been provided
252 before the call.) Flushing may degrade compression for some compression
253 algorithms and so it should be used only when necessary.
254
255 If flush is set to Z_FULL_FLUSH, all output is flushed as with
256 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
257 restart from this point if previous compressed data has been damaged or if
258 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
259 the compression.
260
261 If deflate returns with avail_out == 0, this function must be called again
262 with the same value of the flush parameter and more output space (updated
263 avail_out), until the flush is complete (deflate returns with non-zero
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264 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
265 avail_out is greater than six to avoid repeated flush markers due to
266 avail_out == 0 on return.
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267
268 If the parameter flush is set to Z_FINISH, pending input is processed,
269 pending output is flushed and deflate returns with Z_STREAM_END if there
270 was enough output space; if deflate returns with Z_OK, this function must be
271 called again with Z_FINISH and more output space (updated avail_out) but no
272 more input data, until it returns with Z_STREAM_END or an error. After
273 deflate has returned Z_STREAM_END, the only possible operations on the
274 stream are deflateReset or deflateEnd.
1e1cf689 275
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276 Z_FINISH can be used immediately after deflateInit if all the compression
277 is to be done in a single step. In this case, avail_out must be at least
1e1cf689 278 the value returned by deflateBound (see below). If deflate does not return
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279 Z_STREAM_END, then it must be called again as described above.
280
281 deflate() sets strm->adler to the adler32 checksum of all input read
282 so far (that is, total_in bytes).
283
284 deflate() may update data_type if it can make a good guess about
285 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
286 binary. This field is only for information purposes and does not affect
287 the compression algorithm in any manner.
288
289 deflate() returns Z_OK if some progress has been made (more input
290 processed or more output produced), Z_STREAM_END if all input has been
291 consumed and all output has been produced (only when flush is set to
292 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
06b91d8e 293 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
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294 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
295 fatal, and deflate() can be called again with more input and more output
296 space to continue compressing.
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297*/
298
299
06b91d8e 300ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
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301/*
302 All dynamically allocated data structures for this stream are freed.
303 This function discards any unprocessed input and does not flush any
304 pending output.
305
306 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
307 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
308 prematurely (some input or output was discarded). In the error case,
309 msg may be set but then points to a static string (which must not be
310 deallocated).
311*/
312
313
1e1cf689 314/*
06b91d8e 315ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
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316
317 Initializes the internal stream state for decompression. The fields
318 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
319 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
320 value depends on the compression method), inflateInit determines the
321 compression method from the zlib header and allocates all data structures
322 accordingly; otherwise the allocation will be deferred to the first call of
323 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
324 use default allocation functions.
325
326 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
327 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
328 version assumed by the caller. msg is set to null if there is no error
329 message. inflateInit does not perform any decompression apart from reading
330 the zlib header if present: this will be done by inflate(). (So next_in and
331 avail_in may be modified, but next_out and avail_out are unchanged.)
332*/
333
334
06b91d8e 335ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
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336/*
337 inflate decompresses as much data as possible, and stops when the input
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338 buffer becomes empty or the output buffer becomes full. It may introduce
339 some output latency (reading input without producing any output) except when
340 forced to flush.
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341
342 The detailed semantics are as follows. inflate performs one or both of the
343 following actions:
344
345 - Decompress more input starting at next_in and update next_in and avail_in
346 accordingly. If not all input can be processed (because there is not
347 enough room in the output buffer), next_in is updated and processing
348 will resume at this point for the next call of inflate().
349
350 - Provide more output starting at next_out and update next_out and avail_out
351 accordingly. inflate() provides as much output as possible, until there
352 is no more input data or no more space in the output buffer (see below
353 about the flush parameter).
354
355 Before the call of inflate(), the application should ensure that at least
356 one of the actions is possible, by providing more input and/or consuming
357 more output, and updating the next_* and avail_* values accordingly.
358 The application can consume the uncompressed output when it wants, for
359 example when the output buffer is full (avail_out == 0), or after each
360 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
361 must be called again after making room in the output buffer because there
362 might be more output pending.
363
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364 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
365 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
366 output as possible to the output buffer. Z_BLOCK requests that inflate() stop
367 if and when it get to the next deflate block boundary. When decoding the zlib
368 or gzip format, this will cause inflate() to return immediately after the
369 header and before the first block. When doing a raw inflate, inflate() will
370 go ahead and process the first block, and will return when it gets to the end
371 of that block, or when it runs out of data.
372
373 The Z_BLOCK option assists in appending to or combining deflate streams.
374 Also to assist in this, on return inflate() will set strm->data_type to the
375 number of unused bits in the last byte taken from strm->next_in, plus 64
376 if inflate() is currently decoding the last block in the deflate stream,
377 plus 128 if inflate() returned immediately after decoding an end-of-block
378 code or decoding the complete header up to just before the first byte of the
379 deflate stream. The end-of-block will not be indicated until all of the
380 uncompressed data from that block has been written to strm->next_out. The
381 number of unused bits may in general be greater than seven, except when
382 bit 7 of data_type is set, in which case the number of unused bits will be
383 less than eight.
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384
385 inflate() should normally be called until it returns Z_STREAM_END or an
386 error. However if all decompression is to be performed in a single step
387 (a single call of inflate), the parameter flush should be set to
388 Z_FINISH. In this case all pending input is processed and all pending
389 output is flushed; avail_out must be large enough to hold all the
390 uncompressed data. (The size of the uncompressed data may have been saved
391 by the compressor for this purpose.) The next operation on this stream must
392 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
1e1cf689 393 is never required, but can be used to inform inflate that a faster approach
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394 may be used for the single inflate() call.
395
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396 In this implementation, inflate() always flushes as much output as
397 possible to the output buffer, and always uses the faster approach on the
398 first call. So the only effect of the flush parameter in this implementation
399 is on the return value of inflate(), as noted below, or when it returns early
400 because Z_BLOCK is used.
401
402 If a preset dictionary is needed after this call (see inflateSetDictionary
403 below), inflate sets strm->adler to the adler32 checksum of the dictionary
404 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
405 strm->adler to the adler32 checksum of all output produced so far (that is,
406 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
407 below. At the end of the stream, inflate() checks that its computed adler32
408 checksum is equal to that saved by the compressor and returns Z_STREAM_END
409 only if the checksum is correct.
410
411 inflate() will decompress and check either zlib-wrapped or gzip-wrapped
412 deflate data. The header type is detected automatically. Any information
413 contained in the gzip header is not retained, so applications that need that
414 information should instead use raw inflate, see inflateInit2() below, or
415 inflateBack() and perform their own processing of the gzip header and
416 trailer.
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417
418 inflate() returns Z_OK if some progress has been made (more input processed
419 or more output produced), Z_STREAM_END if the end of the compressed data has
420 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
421 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
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422 corrupted (input stream not conforming to the zlib format or incorrect check
423 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
424 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
425 Z_BUF_ERROR if no progress is possible or if there was not enough room in the
426 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
427 inflate() can be called again with more input and more output space to
428 continue decompressing. If Z_DATA_ERROR is returned, the application may then
429 call inflateSync() to look for a good compression block if a partial recovery
430 of the data is desired.
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431*/
432
433
06b91d8e 434ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
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435/*
436 All dynamically allocated data structures for this stream are freed.
437 This function discards any unprocessed input and does not flush any
438 pending output.
439
440 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
441 was inconsistent. In the error case, msg may be set but then points to a
442 static string (which must not be deallocated).
443*/
444
445 /* Advanced functions */
446
447/*
448 The following functions are needed only in some special applications.
449*/
450
1e1cf689 451/*
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452ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
453 int level,
454 int method,
455 int windowBits,
456 int memLevel,
457 int strategy));
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458
459 This is another version of deflateInit with more compression options. The
460 fields next_in, zalloc, zfree and opaque must be initialized before by
461 the caller.
462
463 The method parameter is the compression method. It must be Z_DEFLATED in
464 this version of the library.
465
466 The windowBits parameter is the base two logarithm of the window size
1e1cf689 467 (the size of the history buffer). It should be in the range 8..15 for this
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468 version of the library. Larger values of this parameter result in better
469 compression at the expense of memory usage. The default value is 15 if
470 deflateInit is used instead.
471
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472 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
473 determines the window size. deflate() will then generate raw deflate data
474 with no zlib header or trailer, and will not compute an adler32 check value.
475
476 windowBits can also be greater than 15 for optional gzip encoding. Add
477 16 to windowBits to write a simple gzip header and trailer around the
478 compressed data instead of a zlib wrapper. The gzip header will have no
479 file name, no extra data, no comment, no modification time (set to zero),
480 no header crc, and the operating system will be set to 255 (unknown). If a
481 gzip stream is being written, strm->adler is a crc32 instead of an adler32.
482
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483 The memLevel parameter specifies how much memory should be allocated
484 for the internal compression state. memLevel=1 uses minimum memory but
485 is slow and reduces compression ratio; memLevel=9 uses maximum memory
486 for optimal speed. The default value is 8. See zconf.h for total memory
487 usage as a function of windowBits and memLevel.
488
489 The strategy parameter is used to tune the compression algorithm. Use the
490 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
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491 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
492 string match), or Z_RLE to limit match distances to one (run-length
493 encoding). Filtered data consists mostly of small values with a somewhat
494 random distribution. In this case, the compression algorithm is tuned to
495 compress them better. The effect of Z_FILTERED is to force more Huffman
496 coding and less string matching; it is somewhat intermediate between
497 Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
498 Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
499 parameter only affects the compression ratio but not the correctness of the
500 compressed output even if it is not set appropriately.
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501
502 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
503 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
504 method). msg is set to null if there is no error message. deflateInit2 does
505 not perform any compression: this will be done by deflate().
506*/
1e1cf689 507
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508ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
509 const Bytef *dictionary,
510 uInt dictLength));
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511/*
512 Initializes the compression dictionary from the given byte sequence
513 without producing any compressed output. This function must be called
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514 immediately after deflateInit, deflateInit2 or deflateReset, before any
515 call of deflate. The compressor and decompressor must use exactly the same
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516 dictionary (see inflateSetDictionary).
517
518 The dictionary should consist of strings (byte sequences) that are likely
519 to be encountered later in the data to be compressed, with the most commonly
520 used strings preferably put towards the end of the dictionary. Using a
521 dictionary is most useful when the data to be compressed is short and can be
522 predicted with good accuracy; the data can then be compressed better than
523 with the default empty dictionary.
524
525 Depending on the size of the compression data structures selected by
526 deflateInit or deflateInit2, a part of the dictionary may in effect be
527 discarded, for example if the dictionary is larger than the window size in
528 deflate or deflate2. Thus the strings most likely to be useful should be
529 put at the end of the dictionary, not at the front.
530
1e1cf689 531 Upon return of this function, strm->adler is set to the adler32 value
d4286ec4 532 of the dictionary; the decompressor may later use this value to determine
1e1cf689 533 which dictionary has been used by the compressor. (The adler32 value
d4286ec4 534 applies to the whole dictionary even if only a subset of the dictionary is
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535 actually used by the compressor.) If a raw deflate was requested, then the
536 adler32 value is not computed and strm->adler is not set.
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537
538 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
539 parameter is invalid (such as NULL dictionary) or the stream state is
540 inconsistent (for example if deflate has already been called for this stream
541 or if the compression method is bsort). deflateSetDictionary does not
542 perform any compression: this will be done by deflate().
543*/
544
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545ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
546 z_streamp source));
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547/*
548 Sets the destination stream as a complete copy of the source stream.
549
550 This function can be useful when several compression strategies will be
551 tried, for example when there are several ways of pre-processing the input
552 data with a filter. The streams that will be discarded should then be freed
553 by calling deflateEnd. Note that deflateCopy duplicates the internal
554 compression state which can be quite large, so this strategy is slow and
555 can consume lots of memory.
556
557 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
558 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
559 (such as zalloc being NULL). msg is left unchanged in both source and
560 destination.
561*/
562
06b91d8e 563ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
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564/*
565 This function is equivalent to deflateEnd followed by deflateInit,
566 but does not free and reallocate all the internal compression state.
567 The stream will keep the same compression level and any other attributes
568 that may have been set by deflateInit2.
569
570 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
571 stream state was inconsistent (such as zalloc or state being NULL).
572*/
573
06b91d8e 574ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
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575 int level,
576 int strategy));
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577/*
578 Dynamically update the compression level and compression strategy. The
579 interpretation of level and strategy is as in deflateInit2. This can be
580 used to switch between compression and straight copy of the input data, or
581 to switch to a different kind of input data requiring a different
582 strategy. If the compression level is changed, the input available so far
583 is compressed with the old level (and may be flushed); the new level will
584 take effect only at the next call of deflate().
585
586 Before the call of deflateParams, the stream state must be set as for
587 a call of deflate(), since the currently available input may have to
588 be compressed and flushed. In particular, strm->avail_out must be non-zero.
589
590 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
591 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
592 if strm->avail_out was zero.
593*/
594
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595ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
596 uLong sourceLen));
597/*
598 deflateBound() returns an upper bound on the compressed size after
599 deflation of sourceLen bytes. It must be called after deflateInit()
600 or deflateInit2(). This would be used to allocate an output buffer
601 for deflation in a single pass, and so would be called before deflate().
602*/
603
604ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
605 int bits,
606 int value));
607/*
608 deflatePrime() inserts bits in the deflate output stream. The intent
609 is that this function is used to start off the deflate output with the
610 bits leftover from a previous deflate stream when appending to it. As such,
611 this function can only be used for raw deflate, and must be used before the
612 first deflate() call after a deflateInit2() or deflateReset(). bits must be
613 less than or equal to 16, and that many of the least significant bits of
614 value will be inserted in the output.
615
616 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
617 stream state was inconsistent.
618*/
619
620/*
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621ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
622 int windowBits));
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623
624 This is another version of inflateInit with an extra parameter. The
625 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
626 before by the caller.
627
628 The windowBits parameter is the base two logarithm of the maximum window
629 size (the size of the history buffer). It should be in the range 8..15 for
630 this version of the library. The default value is 15 if inflateInit is used
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631 instead. windowBits must be greater than or equal to the windowBits value
632 provided to deflateInit2() while compressing, or it must be equal to 15 if
633 deflateInit2() was not used. If a compressed stream with a larger window
634 size is given as input, inflate() will return with the error code
635 Z_DATA_ERROR instead of trying to allocate a larger window.
636
637 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
638 determines the window size. inflate() will then process raw deflate data,
639 not looking for a zlib or gzip header, not generating a check value, and not
640 looking for any check values for comparison at the end of the stream. This
641 is for use with other formats that use the deflate compressed data format
642 such as zip. Those formats provide their own check values. If a custom
643 format is developed using the raw deflate format for compressed data, it is
644 recommended that a check value such as an adler32 or a crc32 be applied to
645 the uncompressed data as is done in the zlib, gzip, and zip formats. For
646 most applications, the zlib format should be used as is. Note that comments
647 above on the use in deflateInit2() applies to the magnitude of windowBits.
648
649 windowBits can also be greater than 15 for optional gzip decoding. Add
650 32 to windowBits to enable zlib and gzip decoding with automatic header
651 detection, or add 16 to decode only the gzip format (the zlib format will
652 return a Z_DATA_ERROR. If a gzip stream is being decoded, strm->adler is
653 a crc32 instead of an adler32.
654
655 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
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656 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
657 memLevel). msg is set to null if there is no error message. inflateInit2
658 does not perform any decompression apart from reading the zlib header if
659 present: this will be done by inflate(). (So next_in and avail_in may be
660 modified, but next_out and avail_out are unchanged.)
661*/
662
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663ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
664 const Bytef *dictionary,
665 uInt dictLength));
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666/*
667 Initializes the decompression dictionary from the given uncompressed byte
668 sequence. This function must be called immediately after a call of inflate
669 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
1e1cf689 670 can be determined from the adler32 value returned by this call of
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671 inflate. The compressor and decompressor must use exactly the same
672 dictionary (see deflateSetDictionary).
673
674 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
675 parameter is invalid (such as NULL dictionary) or the stream state is
676 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
1e1cf689 677 expected one (incorrect adler32 value). inflateSetDictionary does not
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678 perform any decompression: this will be done by subsequent calls of
679 inflate().
680*/
681
06b91d8e 682ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
1e1cf689 683/*
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684 Skips invalid compressed data until a full flush point (see above the
685 description of deflate with Z_FULL_FLUSH) can be found, or until all
686 available input is skipped. No output is provided.
687
688 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
689 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
690 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
691 case, the application may save the current current value of total_in which
692 indicates where valid compressed data was found. In the error case, the
693 application may repeatedly call inflateSync, providing more input each time,
694 until success or end of the input data.
695*/
696
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697ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
698 z_streamp source));
699/*
700 Sets the destination stream as a complete copy of the source stream.
701
702 This function can be useful when randomly accessing a large stream. The
703 first pass through the stream can periodically record the inflate state,
704 allowing restarting inflate at those points when randomly accessing the
705 stream.
706
707 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
708 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
709 (such as zalloc being NULL). msg is left unchanged in both source and
710 destination.
711*/
712
06b91d8e 713ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
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714/*
715 This function is equivalent to inflateEnd followed by inflateInit,
716 but does not free and reallocate all the internal decompression state.
717 The stream will keep attributes that may have been set by inflateInit2.
718
719 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
720 stream state was inconsistent (such as zalloc or state being NULL).
721*/
722
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723/*
724ZEXTERN int ZEXPORT inflateBackInit OF((z_stream FAR *strm, int windowBits,
725 unsigned char FAR *window));
726
727 Initialize the internal stream state for decompression using inflateBack()
728 calls. The fields zalloc, zfree and opaque in strm must be initialized
729 before the call. If zalloc and zfree are Z_NULL, then the default library-
730 derived memory allocation routines are used. windowBits is the base two
731 logarithm of the window size, in the range 8..15. window is a caller
732 supplied buffer of that size. Except for special applications where it is
733 assured that deflate was used with small window sizes, windowBits must be 15
734 and a 32K byte window must be supplied to be able to decompress general
735 deflate streams.
736
737 See inflateBack() for the usage of these routines.
738
739 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
740 the paramaters are invalid, Z_MEM_ERROR if the internal state could not
741 be allocated, or Z_VERSION_ERROR if the version of the library does not
742 match the version of the header file.
743*/
744
745typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
746typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
747
748ZEXTERN int ZEXPORT inflateBack OF((z_stream FAR *strm,
749 in_func in, void FAR *in_desc,
750 out_func out, void FAR *out_desc));
751/*
752 inflateBack() does a raw inflate with a single call using a call-back
753 interface for input and output. This is more efficient than inflate() for
754 file i/o applications in that it avoids copying between the output and the
755 sliding window by simply making the window itself the output buffer. This
756 function trusts the application to not change the output buffer passed by
757 the output function, at least until inflateBack() returns.
758
759 inflateBackInit() must be called first to allocate the internal state
760 and to initialize the state with the user-provided window buffer.
761 inflateBack() may then be used multiple times to inflate a complete, raw
762 deflate stream with each call. inflateBackEnd() is then called to free
763 the allocated state.
764
765 A raw deflate stream is one with no zlib or gzip header or trailer.
766 This routine would normally be used in a utility that reads zip or gzip
767 files and writes out uncompressed files. The utility would decode the
768 header and process the trailer on its own, hence this routine expects
769 only the raw deflate stream to decompress. This is different from the
770 normal behavior of inflate(), which expects either a zlib or gzip header and
771 trailer around the deflate stream.
772
773 inflateBack() uses two subroutines supplied by the caller that are then
774 called by inflateBack() for input and output. inflateBack() calls those
775 routines until it reads a complete deflate stream and writes out all of the
776 uncompressed data, or until it encounters an error. The function's
777 parameters and return types are defined above in the in_func and out_func
778 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
779 number of bytes of provided input, and a pointer to that input in buf. If
780 there is no input available, in() must return zero--buf is ignored in that
781 case--and inflateBack() will return a buffer error. inflateBack() will call
782 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
783 should return zero on success, or non-zero on failure. If out() returns
784 non-zero, inflateBack() will return with an error. Neither in() nor out()
785 are permitted to change the contents of the window provided to
786 inflateBackInit(), which is also the buffer that out() uses to write from.
787 The length written by out() will be at most the window size. Any non-zero
788 amount of input may be provided by in().
789
790 For convenience, inflateBack() can be provided input on the first call by
791 setting strm->next_in and strm->avail_in. If that input is exhausted, then
792 in() will be called. Therefore strm->next_in must be initialized before
793 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
794 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
795 must also be initialized, and then if strm->avail_in is not zero, input will
796 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
797
798 The in_desc and out_desc parameters of inflateBack() is passed as the
799 first parameter of in() and out() respectively when they are called. These
800 descriptors can be optionally used to pass any information that the caller-
801 supplied in() and out() functions need to do their job.
802
803 On return, inflateBack() will set strm->next_in and strm->avail_in to
804 pass back any unused input that was provided by the last in() call. The
805 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
806 if in() or out() returned an error, Z_DATA_ERROR if there was a format
807 error in the deflate stream (in which case strm->msg is set to indicate the
808 nature of the error), or Z_STREAM_ERROR if the stream was not properly
809 initialized. In the case of Z_BUF_ERROR, an input or output error can be
810 distinguished using strm->next_in which will be Z_NULL only if in() returned
811 an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
812 out() returning non-zero. (in() will always be called before out(), so
813 strm->next_in is assured to be defined if out() returns non-zero.) Note
814 that inflateBack() cannot return Z_OK.
815*/
816
817ZEXTERN int ZEXPORT inflateBackEnd OF((z_stream FAR *strm));
818/*
819 All memory allocated by inflateBackInit() is freed.
820
821 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
822 state was inconsistent.
823*/
824
825ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
826/* Return flags indicating compile-time options.
827
828 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
829 1.0: size of uInt
830 3.2: size of uLong
831 5.4: size of voidpf (pointer)
832 7.6: size of z_off_t
833
834 Compiler, assembler, and debug options:
835 8: DEBUG
836 9: ASMV or ASMINF -- use ASM code
837 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
838 11: 0 (reserved)
839
840 One-time table building (smaller code, but not thread-safe if true):
841 12: BUILDFIXED -- build static block decoding tables when needed
842 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
843 14,15: 0 (reserved)
844
845 Library content (indicates missing functionality):
846 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
847 deflate code when not needed)
848 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
849 and decode gzip streams (to avoid linking crc code)
850 18-19: 0 (reserved)
851
852 Operation variations (changes in library functionality):
853 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
854 21: FASTEST -- deflate algorithm with only one, lowest compression level
855 22,23: 0 (reserved)
856
857 The sprintf variant used by gzprintf (zero is best):
858 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
859 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
860 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
861
862 Remainder:
863 27-31: 0 (reserved)
864 */
865
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866
867 /* utility functions */
868
869/*
870 The following utility functions are implemented on top of the
871 basic stream-oriented functions. To simplify the interface, some
872 default options are assumed (compression level and memory usage,
873 standard memory allocation functions). The source code of these
874 utility functions can easily be modified if you need special options.
875*/
876
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877ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
878 const Bytef *source, uLong sourceLen));
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879/*
880 Compresses the source buffer into the destination buffer. sourceLen is
881 the byte length of the source buffer. Upon entry, destLen is the total
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882 size of the destination buffer, which must be at least the value returned
883 by compressBound(sourceLen). Upon exit, destLen is the actual size of the
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884 compressed buffer.
885 This function can be used to compress a whole file at once if the
886 input file is mmap'ed.
887 compress returns Z_OK if success, Z_MEM_ERROR if there was not
888 enough memory, Z_BUF_ERROR if there was not enough room in the output
889 buffer.
890*/
891
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892ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
893 const Bytef *source, uLong sourceLen,
894 int level));
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895/*
896 Compresses the source buffer into the destination buffer. The level
897 parameter has the same meaning as in deflateInit. sourceLen is the byte
898 length of the source buffer. Upon entry, destLen is the total size of the
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899 destination buffer, which must be at least the value returned by
900 compressBound(sourceLen). Upon exit, destLen is the actual size of the
901 compressed buffer.
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902
903 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
904 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
905 Z_STREAM_ERROR if the level parameter is invalid.
906*/
907
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908ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
909/*
910 compressBound() returns an upper bound on the compressed size after
911 compress() or compress2() on sourceLen bytes. It would be used before
912 a compress() or compress2() call to allocate the destination buffer.
913*/
914
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915ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
916 const Bytef *source, uLong sourceLen));
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917/*
918 Decompresses the source buffer into the destination buffer. sourceLen is
919 the byte length of the source buffer. Upon entry, destLen is the total
920 size of the destination buffer, which must be large enough to hold the
921 entire uncompressed data. (The size of the uncompressed data must have
922 been saved previously by the compressor and transmitted to the decompressor
923 by some mechanism outside the scope of this compression library.)
924 Upon exit, destLen is the actual size of the compressed buffer.
925 This function can be used to decompress a whole file at once if the
926 input file is mmap'ed.
927
928 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
929 enough memory, Z_BUF_ERROR if there was not enough room in the output
1e1cf689 930 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
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931*/
932
933
934typedef voidp gzFile;
935
06b91d8e 936ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
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937/*
938 Opens a gzip (.gz) file for reading or writing. The mode parameter
939 is as in fopen ("rb" or "wb") but can also include a compression level
940 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
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941 Huffman only compression as in "wb1h", or 'R' for run-length encoding
942 as in "wb1R". (See the description of deflateInit2 for more information
943 about the strategy parameter.)
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944
945 gzopen can be used to read a file which is not in gzip format; in this
946 case gzread will directly read from the file without decompression.
947
948 gzopen returns NULL if the file could not be opened or if there was
949 insufficient memory to allocate the (de)compression state; errno
950 can be checked to distinguish the two cases (if errno is zero, the
951 zlib error is Z_MEM_ERROR). */
952
06b91d8e 953ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
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954/*
955 gzdopen() associates a gzFile with the file descriptor fd. File
956 descriptors are obtained from calls like open, dup, creat, pipe or
957 fileno (in the file has been previously opened with fopen).
958 The mode parameter is as in gzopen.
959 The next call of gzclose on the returned gzFile will also close the
960 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
961 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
962 gzdopen returns NULL if there was insufficient memory to allocate
963 the (de)compression state.
964*/
965
06b91d8e 966ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
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967/*
968 Dynamically update the compression level or strategy. See the description
969 of deflateInit2 for the meaning of these parameters.
970 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
971 opened for writing.
972*/
973
06b91d8e 974ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
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975/*
976 Reads the given number of uncompressed bytes from the compressed file.
977 If the input file was not in gzip format, gzread copies the given number
978 of bytes into the buffer.
979 gzread returns the number of uncompressed bytes actually read (0 for
980 end of file, -1 for error). */
981
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982ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
983 voidpc buf, unsigned len));
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984/*
985 Writes the given number of uncompressed bytes into the compressed file.
986 gzwrite returns the number of uncompressed bytes actually written
987 (0 in case of error).
988*/
989
06b91d8e 990ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
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991/*
992 Converts, formats, and writes the args to the compressed file under
993 control of the format string, as in fprintf. gzprintf returns the number of
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994 uncompressed bytes actually written (0 in case of error). The number of
995 uncompressed bytes written is limited to 4095. The caller should assure that
996 this limit is not exceeded. If it is exceeded, then gzprintf() will return
997 return an error (0) with nothing written. In this case, there may also be a
998 buffer overflow with unpredictable consequences, which is possible only if
999 zlib was compiled with the insecure functions sprintf() or vsprintf()
1000 because the secure snprintf() or vsnprintf() functions were not available.
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1001*/
1002
06b91d8e 1003ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
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1004/*
1005 Writes the given null-terminated string to the compressed file, excluding
1006 the terminating null character.
1007 gzputs returns the number of characters written, or -1 in case of error.
1008*/
1009
06b91d8e 1010ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
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1011/*
1012 Reads bytes from the compressed file until len-1 characters are read, or
1013 a newline character is read and transferred to buf, or an end-of-file
1014 condition is encountered. The string is then terminated with a null
1015 character.
1016 gzgets returns buf, or Z_NULL in case of error.
1017*/
1018
06b91d8e 1019ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
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1020/*
1021 Writes c, converted to an unsigned char, into the compressed file.
1022 gzputc returns the value that was written, or -1 in case of error.
1023*/
1024
06b91d8e 1025ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
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1026/*
1027 Reads one byte from the compressed file. gzgetc returns this byte
1028 or -1 in case of end of file or error.
1029*/
1030
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1031ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1032/*
1033 Push one character back onto the stream to be read again later.
1034 Only one character of push-back is allowed. gzungetc() returns the
1035 character pushed, or -1 on failure. gzungetc() will fail if a
1036 character has been pushed but not read yet, or if c is -1. The pushed
1037 character will be discarded if the stream is repositioned with gzseek()
1038 or gzrewind().
1039*/
1040
06b91d8e 1041ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
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1042/*
1043 Flushes all pending output into the compressed file. The parameter
1044 flush is as in the deflate() function. The return value is the zlib
1045 error number (see function gzerror below). gzflush returns Z_OK if
1046 the flush parameter is Z_FINISH and all output could be flushed.
1047 gzflush should be called only when strictly necessary because it can
1048 degrade compression.
1049*/
1050
06b91d8e 1051ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
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1052 z_off_t offset, int whence));
1053/*
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1054 Sets the starting position for the next gzread or gzwrite on the
1055 given compressed file. The offset represents a number of bytes in the
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1056 uncompressed data stream. The whence parameter is defined as in lseek(2);
1057 the value SEEK_END is not supported.
1058 If the file is opened for reading, this function is emulated but can be
1059 extremely slow. If the file is opened for writing, only forward seeks are
1060 supported; gzseek then compresses a sequence of zeroes up to the new
1061 starting position.
1062
1063 gzseek returns the resulting offset location as measured in bytes from
1064 the beginning of the uncompressed stream, or -1 in case of error, in
1065 particular if the file is opened for writing and the new starting position
1066 would be before the current position.
1067*/
1068
06b91d8e 1069ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
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1070/*
1071 Rewinds the given file. This function is supported only for reading.
1072
1073 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1074*/
1075
06b91d8e 1076ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
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1077/*
1078 Returns the starting position for the next gzread or gzwrite on the
1079 given compressed file. This position represents a number of bytes in the
1080 uncompressed data stream.
1081
1082 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1083*/
1084
06b91d8e 1085ZEXTERN int ZEXPORT gzeof OF((gzFile file));
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1086/*
1087 Returns 1 when EOF has previously been detected reading the given
1088 input stream, otherwise zero.
1089*/
1090
06b91d8e 1091ZEXTERN int ZEXPORT gzclose OF((gzFile file));
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1092/*
1093 Flushes all pending output if necessary, closes the compressed file
1094 and deallocates all the (de)compression state. The return value is the zlib
1095 error number (see function gzerror below).
1096*/
1097
06b91d8e 1098ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
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1099/*
1100 Returns the error message for the last error which occurred on the
1101 given compressed file. errnum is set to zlib error number. If an
1102 error occurred in the file system and not in the compression library,
1103 errnum is set to Z_ERRNO and the application may consult errno
1104 to get the exact error code.
1105*/
1106
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1107ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1108/*
1109 Clears the error and end-of-file flags for file. This is analogous to the
1110 clearerr() function in stdio. This is useful for continuing to read a gzip
1111 file that is being written concurrently.
1112*/
1113
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1114 /* checksum functions */
1115
1116/*
1117 These functions are not related to compression but are exported
1118 anyway because they might be useful in applications using the
1119 compression library.
1120*/
1121
06b91d8e 1122ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
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1123
1124/*
1125 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1126 return the updated checksum. If buf is NULL, this function returns
1127 the required initial value for the checksum.
1128 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1129 much faster. Usage example:
1130
1131 uLong adler = adler32(0L, Z_NULL, 0);
1132
1133 while (read_buffer(buffer, length) != EOF) {
1134 adler = adler32(adler, buffer, length);
1135 }
1136 if (adler != original_adler) error();
1137*/
1138
06b91d8e 1139ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
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1140/*
1141 Update a running crc with the bytes buf[0..len-1] and return the updated
1142 crc. If buf is NULL, this function returns the required initial value
1143 for the crc. Pre- and post-conditioning (one's complement) is performed
1144 within this function so it shouldn't be done by the application.
1145 Usage example:
1146
1147 uLong crc = crc32(0L, Z_NULL, 0);
1148
1149 while (read_buffer(buffer, length) != EOF) {
1150 crc = crc32(crc, buffer, length);
1151 }
1152 if (crc != original_crc) error();
1153*/
1154
1155
1156 /* various hacks, don't look :) */
1157
1158/* deflateInit and inflateInit are macros to allow checking the zlib version
1159 * and the compiler's view of z_stream:
1160 */
06b91d8e 1161ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
d4286ec4 1162 const char *version, int stream_size));
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1163ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1164 const char *version, int stream_size));
1165ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1166 int windowBits, int memLevel,
1167 int strategy, const char *version,
1168 int stream_size));
1169ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1170 const char *version, int stream_size));
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1171ZEXTERN int ZEXPORT inflateBackInit_ OF((z_stream FAR *strm, int windowBits,
1172 unsigned char FAR *window,
1173 const char *version,
1174 int stream_size));
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1175#define deflateInit(strm, level) \
1176 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
1177#define inflateInit(strm) \
1178 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
1179#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1180 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1181 (strategy), ZLIB_VERSION, sizeof(z_stream))
1182#define inflateInit2(strm, windowBits) \
1183 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
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1184#define inflateBackInit(strm, windowBits, window) \
1185 inflateBackInit_((strm), (windowBits), (window), \
1186 ZLIB_VERSION, sizeof(z_stream))
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1187
1188
1e1cf689 1189#if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
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1190 struct internal_state {int dummy;}; /* hack for buggy compilers */
1191#endif
1192
1e1cf689 1193ZEXTERN const char * ZEXPORT zError OF((int));
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1194ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
1195ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
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1196
1197#ifdef __cplusplus
1198}
1199#endif
1200
1e1cf689 1201#endif /* ZLIB_H */