1
/* zlib.h -- interface of the 'zlib' general purpose compression library
2
version 1.1.4, March 11th, 2002
4
Copyright (C) 1995-2002 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 ftp://ds.internic.net/rfc/rfc1950.txt
28
(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
40
#define ZLIB_VERSION "1.1.4"
43
The 'zlib' compression library provides in-memory compression and
44
decompression functions, including integrity checks of the uncompressed
45
data. This version of the library supports only one compression method
46
(deflation) but other algorithms will be added later and will have the same
49
Compression can be done in a single step if the buffers are large
50
enough (for example if an input file is mmap'ed), or can be done by
51
repeated calls of the compression function. In the latter case, the
52
application must provide more input and/or consume the output
53
(providing more output space) before each call.
55
The library also supports reading and writing files in gzip (.gz) format
56
with an interface similar to that of stdio.
58
The library does not install any signal handler. The decoder checks
59
the consistency of the compressed data, so the library should never
60
crash even in case of corrupted input.
63
typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
64
typedef void (*free_func) OF((voidpf opaque, voidpf address));
66
struct internal_state;
68
typedef struct z_stream_s {
69
Bytef *next_in; /* next input byte */
70
uInt avail_in; /* number of bytes available at next_in */
71
uLong total_in; /* total nb of input bytes read so far */
73
Bytef *next_out; /* next output byte should be put there */
74
uInt avail_out; /* remaining free space at next_out */
75
uLong total_out; /* total nb of bytes output so far */
77
char *msg; /* last error message, NULL if no error */
78
struct internal_state FAR *state; /* not visible by applications */
80
alloc_func zalloc; /* used to allocate the internal state */
81
free_func zfree; /* used to free the internal state */
82
voidpf opaque; /* private data object passed to zalloc and zfree */
84
int data_type; /* best guess about the data type: ascii or binary */
85
uLong adler; /* adler32 value of the uncompressed data */
86
uLong reserved; /* reserved for future use */
89
typedef z_stream FAR *z_streamp;
92
The application must update next_in and avail_in when avail_in has
93
dropped to zero. It must update next_out and avail_out when avail_out
94
has dropped to zero. The application must initialize zalloc, zfree and
95
opaque before calling the init function. All other fields are set by the
96
compression library and must not be updated by the application.
98
The opaque value provided by the application will be passed as the first
99
parameter for calls of zalloc and zfree. This can be useful for custom
100
memory management. The compression library attaches no meaning to the
103
zalloc must return Z_NULL if there is not enough memory for the object.
104
If zlib is used in a multi-threaded application, zalloc and zfree must be
107
On 16-bit systems, the functions zalloc and zfree must be able to allocate
108
exactly 65536 bytes, but will not be required to allocate more than this
109
if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
110
pointers returned by zalloc for objects of exactly 65536 bytes *must*
111
have their offset normalized to zero. The default allocation function
112
provided by this library ensures this (see zutil.c). To reduce memory
113
requirements and avoid any allocation of 64K objects, at the expense of
114
compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
116
The fields total_in and total_out can be used for statistics or
117
progress reports. After compression, total_in holds the total size of
118
the uncompressed data and may be saved for use in the decompressor
119
(particularly if the decompressor wants to decompress everything in
126
#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
127
#define Z_SYNC_FLUSH 2
128
#define Z_FULL_FLUSH 3
130
/* Allowed flush values; see deflate() below for details */
133
#define Z_STREAM_END 1
134
#define Z_NEED_DICT 2
136
#define Z_STREAM_ERROR (-2)
137
#define Z_DATA_ERROR (-3)
138
#define Z_MEM_ERROR (-4)
139
#define Z_BUF_ERROR (-5)
140
#define Z_VERSION_ERROR (-6)
141
/* Return codes for the compression/decompression functions. Negative
142
* values are errors, positive values are used for special but normal events.
145
#define Z_NO_COMPRESSION 0
146
#define Z_BEST_SPEED 1
147
#define Z_BEST_COMPRESSION 9
148
#define Z_DEFAULT_COMPRESSION (-1)
149
/* compression levels */
152
#define Z_HUFFMAN_ONLY 2
153
#define Z_DEFAULT_STRATEGY 0
154
/* compression strategy; see deflateInit2() below for details */
159
/* Possible values of the data_type field */
162
/* The deflate compression method (the only one supported in this version) */
164
#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
166
#define zlib_version zlibVersion()
167
/* for compatibility with versions < 1.0.2 */
169
/* basic functions */
171
ZEXTERN const char * ZEXPORT zlibVersion OF((void));
172
/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
173
If the first character differs, the library code actually used is
174
not compatible with the zlib.h header file used by the application.
175
This check is automatically made by deflateInit and inflateInit.
179
ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
181
Initializes the internal stream state for compression. The fields
182
zalloc, zfree and opaque must be initialized before by the caller.
183
If zalloc and zfree are set to Z_NULL, deflateInit updates them to
184
use default allocation functions.
186
The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
187
1 gives best speed, 9 gives best compression, 0 gives no compression at
188
all (the input data is simply copied a block at a time).
189
Z_DEFAULT_COMPRESSION requests a default compromise between speed and
190
compression (currently equivalent to level 6).
192
deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
193
enough memory, Z_STREAM_ERROR if level is not a valid compression level,
194
Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
195
with the version assumed by the caller (ZLIB_VERSION).
196
msg is set to null if there is no error message. deflateInit does not
197
perform any compression: this will be done by deflate().
201
ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
203
deflate compresses as much data as possible, and stops when the input
204
buffer becomes empty or the output buffer becomes full. It may introduce some
205
output latency (reading input without producing any output) except when
208
The detailed semantics are as follows. deflate performs one or both of the
211
- Compress more input starting at next_in and update next_in and avail_in
212
accordingly. If not all input can be processed (because there is not
213
enough room in the output buffer), next_in and avail_in are updated and
214
processing will resume at this point for the next call of deflate().
216
- Provide more output starting at next_out and update next_out and avail_out
217
accordingly. This action is forced if the parameter flush is non zero.
218
Forcing flush frequently degrades the compression ratio, so this parameter
219
should be set only when necessary (in interactive applications).
220
Some output may be provided even if flush is not set.
222
Before the call of deflate(), the application should ensure that at least
223
one of the actions is possible, by providing more input and/or consuming
224
more output, and updating avail_in or avail_out accordingly; avail_out
225
should never be zero before the call. The application can consume the
226
compressed output when it wants, for example when the output buffer is full
227
(avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
228
and with zero avail_out, it must be called again after making room in the
229
output buffer because there might be more output pending.
231
If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
232
flushed to the output buffer and the output is aligned on a byte boundary, so
233
that the decompressor can get all input data available so far. (In particular
234
avail_in is zero after the call if enough output space has been provided
235
before the call.) Flushing may degrade compression for some compression
236
algorithms and so it should be used only when necessary.
238
If flush is set to Z_FULL_FLUSH, all output is flushed as with
239
Z_SYNC_FLUSH, and the compression state is reset so that decompression can
240
restart from this point if previous compressed data has been damaged or if
241
random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
244
If deflate returns with avail_out == 0, this function must be called again
245
with the same value of the flush parameter and more output space (updated
246
avail_out), until the flush is complete (deflate returns with non-zero
249
If the parameter flush is set to Z_FINISH, pending input is processed,
250
pending output is flushed and deflate returns with Z_STREAM_END if there
251
was enough output space; if deflate returns with Z_OK, this function must be
252
called again with Z_FINISH and more output space (updated avail_out) but no
253
more input data, until it returns with Z_STREAM_END or an error. After
254
deflate has returned Z_STREAM_END, the only possible operations on the
255
stream are deflateReset or deflateEnd.
257
Z_FINISH can be used immediately after deflateInit if all the compression
258
is to be done in a single step. In this case, avail_out must be at least
259
0.1% larger than avail_in plus 12 bytes. If deflate does not return
260
Z_STREAM_END, then it must be called again as described above.
262
deflate() sets strm->adler to the adler32 checksum of all input read
263
so far (that is, total_in bytes).
265
deflate() may update data_type if it can make a good guess about
266
the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
267
binary. This field is only for information purposes and does not affect
268
the compression algorithm in any manner.
270
deflate() returns Z_OK if some progress has been made (more input
271
processed or more output produced), Z_STREAM_END if all input has been
272
consumed and all output has been produced (only when flush is set to
273
Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
274
if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
275
(for example avail_in or avail_out was zero).
279
ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
281
All dynamically allocated data structures for this stream are freed.
282
This function discards any unprocessed input and does not flush any
285
deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
286
stream state was inconsistent, Z_DATA_ERROR if the stream was freed
287
prematurely (some input or output was discarded). In the error case,
288
msg may be set but then points to a static string (which must not be
294
ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
296
Initializes the internal stream state for decompression. The fields
297
next_in, avail_in, zalloc, zfree and opaque must be initialized before by
298
the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
299
value depends on the compression method), inflateInit determines the
300
compression method from the zlib header and allocates all data structures
301
accordingly; otherwise the allocation will be deferred to the first call of
302
inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
303
use default allocation functions.
305
inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
306
memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
307
version assumed by the caller. msg is set to null if there is no error
308
message. inflateInit does not perform any decompression apart from reading
309
the zlib header if present: this will be done by inflate(). (So next_in and
310
avail_in may be modified, but next_out and avail_out are unchanged.)
314
ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
316
inflate decompresses as much data as possible, and stops when the input
317
buffer becomes empty or the output buffer becomes full. It may some
318
introduce some output latency (reading input without producing any output)
319
except when forced to flush.
321
The detailed semantics are as follows. inflate performs one or both of the
324
- Decompress more input starting at next_in and update next_in and avail_in
325
accordingly. If not all input can be processed (because there is not
326
enough room in the output buffer), next_in is updated and processing
327
will resume at this point for the next call of inflate().
329
- Provide more output starting at next_out and update next_out and avail_out
330
accordingly. inflate() provides as much output as possible, until there
331
is no more input data or no more space in the output buffer (see below
332
about the flush parameter).
334
Before the call of inflate(), the application should ensure that at least
335
one of the actions is possible, by providing more input and/or consuming
336
more output, and updating the next_* and avail_* values accordingly.
337
The application can consume the uncompressed output when it wants, for
338
example when the output buffer is full (avail_out == 0), or after each
339
call of inflate(). If inflate returns Z_OK and with zero avail_out, it
340
must be called again after making room in the output buffer because there
341
might be more output pending.
343
If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
344
output as possible to the output buffer. The flushing behavior of inflate is
345
not specified for values of the flush parameter other than Z_SYNC_FLUSH
346
and Z_FINISH, but the current implementation actually flushes as much output
349
inflate() should normally be called until it returns Z_STREAM_END or an
350
error. However if all decompression is to be performed in a single step
351
(a single call of inflate), the parameter flush should be set to
352
Z_FINISH. In this case all pending input is processed and all pending
353
output is flushed; avail_out must be large enough to hold all the
354
uncompressed data. (The size of the uncompressed data may have been saved
355
by the compressor for this purpose.) The next operation on this stream must
356
be inflateEnd to deallocate the decompression state. The use of Z_FINISH
357
is never required, but can be used to inform inflate that a faster routine
358
may be used for the single inflate() call.
360
If a preset dictionary is needed at this point (see inflateSetDictionary
361
below), inflate sets strm-adler to the adler32 checksum of the
362
dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
363
it sets strm->adler to the adler32 checksum of all output produced
364
so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
365
an error code as described below. At the end of the stream, inflate()
366
checks that its computed adler32 checksum is equal to that saved by the
367
compressor and returns Z_STREAM_END only if the checksum is correct.
369
inflate() returns Z_OK if some progress has been made (more input processed
370
or more output produced), Z_STREAM_END if the end of the compressed data has
371
been reached and all uncompressed output has been produced, Z_NEED_DICT if a
372
preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
373
corrupted (input stream not conforming to the zlib format or incorrect
374
adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
375
(for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
376
enough memory, Z_BUF_ERROR if no progress is possible or if there was not
377
enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
378
case, the application may then call inflateSync to look for a good
383
ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
385
All dynamically allocated data structures for this stream are freed.
386
This function discards any unprocessed input and does not flush any
389
inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
390
was inconsistent. In the error case, msg may be set but then points to a
391
static string (which must not be deallocated).
394
/* Advanced functions */
397
The following functions are needed only in some special applications.
401
ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
408
This is another version of deflateInit with more compression options. The
409
fields next_in, zalloc, zfree and opaque must be initialized before by
412
The method parameter is the compression method. It must be Z_DEFLATED in
413
this version of the library.
415
The windowBits parameter is the base two logarithm of the window size
416
(the size of the history buffer). It should be in the range 8..15 for this
417
version of the library. Larger values of this parameter result in better
418
compression at the expense of memory usage. The default value is 15 if
419
deflateInit is used instead.
421
The memLevel parameter specifies how much memory should be allocated
422
for the internal compression state. memLevel=1 uses minimum memory but
423
is slow and reduces compression ratio; memLevel=9 uses maximum memory
424
for optimal speed. The default value is 8. See zconf.h for total memory
425
usage as a function of windowBits and memLevel.
427
The strategy parameter is used to tune the compression algorithm. Use the
428
value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
429
filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
430
string match). Filtered data consists mostly of small values with a
431
somewhat random distribution. In this case, the compression algorithm is
432
tuned to compress them better. The effect of Z_FILTERED is to force more
433
Huffman coding and less string matching; it is somewhat intermediate
434
between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
435
the compression ratio but not the correctness of the compressed output even
436
if it is not set appropriately.
438
deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
439
memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
440
method). msg is set to null if there is no error message. deflateInit2 does
441
not perform any compression: this will be done by deflate().
444
ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
445
const Bytef *dictionary,
448
Initializes the compression dictionary from the given byte sequence
449
without producing any compressed output. This function must be called
450
immediately after deflateInit, deflateInit2 or deflateReset, before any
451
call of deflate. The compressor and decompressor must use exactly the same
452
dictionary (see inflateSetDictionary).
454
The dictionary should consist of strings (byte sequences) that are likely
455
to be encountered later in the data to be compressed, with the most commonly
456
used strings preferably put towards the end of the dictionary. Using a
457
dictionary is most useful when the data to be compressed is short and can be
458
predicted with good accuracy; the data can then be compressed better than
459
with the default empty dictionary.
461
Depending on the size of the compression data structures selected by
462
deflateInit or deflateInit2, a part of the dictionary may in effect be
463
discarded, for example if the dictionary is larger than the window size in
464
deflate or deflate2. Thus the strings most likely to be useful should be
465
put at the end of the dictionary, not at the front.
467
Upon return of this function, strm->adler is set to the Adler32 value
468
of the dictionary; the decompressor may later use this value to determine
469
which dictionary has been used by the compressor. (The Adler32 value
470
applies to the whole dictionary even if only a subset of the dictionary is
471
actually used by the compressor.)
473
deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
474
parameter is invalid (such as NULL dictionary) or the stream state is
475
inconsistent (for example if deflate has already been called for this stream
476
or if the compression method is bsort). deflateSetDictionary does not
477
perform any compression: this will be done by deflate().
480
ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
483
Sets the destination stream as a complete copy of the source stream.
485
This function can be useful when several compression strategies will be
486
tried, for example when there are several ways of pre-processing the input
487
data with a filter. The streams that will be discarded should then be freed
488
by calling deflateEnd. Note that deflateCopy duplicates the internal
489
compression state which can be quite large, so this strategy is slow and
490
can consume lots of memory.
492
deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
493
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
494
(such as zalloc being NULL). msg is left unchanged in both source and
498
ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
500
This function is equivalent to deflateEnd followed by deflateInit,
501
but does not free and reallocate all the internal compression state.
502
The stream will keep the same compression level and any other attributes
503
that may have been set by deflateInit2.
505
deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
506
stream state was inconsistent (such as zalloc or state being NULL).
509
ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
513
Dynamically update the compression level and compression strategy. The
514
interpretation of level and strategy is as in deflateInit2. This can be
515
used to switch between compression and straight copy of the input data, or
516
to switch to a different kind of input data requiring a different
517
strategy. If the compression level is changed, the input available so far
518
is compressed with the old level (and may be flushed); the new level will
519
take effect only at the next call of deflate().
521
Before the call of deflateParams, the stream state must be set as for
522
a call of deflate(), since the currently available input may have to
523
be compressed and flushed. In particular, strm->avail_out must be non-zero.
525
deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
526
stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
527
if strm->avail_out was zero.
531
ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
534
This is another version of inflateInit with an extra parameter. The
535
fields next_in, avail_in, zalloc, zfree and opaque must be initialized
536
before by the caller.
538
The windowBits parameter is the base two logarithm of the maximum window
539
size (the size of the history buffer). It should be in the range 8..15 for
540
this version of the library. The default value is 15 if inflateInit is used
541
instead. If a compressed stream with a larger window size is given as
542
input, inflate() will return with the error code Z_DATA_ERROR instead of
543
trying to allocate a larger window.
545
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
546
memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
547
memLevel). msg is set to null if there is no error message. inflateInit2
548
does not perform any decompression apart from reading the zlib header if
549
present: this will be done by inflate(). (So next_in and avail_in may be
550
modified, but next_out and avail_out are unchanged.)
553
ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
554
const Bytef *dictionary,
557
Initializes the decompression dictionary from the given uncompressed byte
558
sequence. This function must be called immediately after a call of inflate
559
if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
560
can be determined from the Adler32 value returned by this call of
561
inflate. The compressor and decompressor must use exactly the same
562
dictionary (see deflateSetDictionary).
564
inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
565
parameter is invalid (such as NULL dictionary) or the stream state is
566
inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
567
expected one (incorrect Adler32 value). inflateSetDictionary does not
568
perform any decompression: this will be done by subsequent calls of
572
ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
574
Skips invalid compressed data until a full flush point (see above the
575
description of deflate with Z_FULL_FLUSH) can be found, or until all
576
available input is skipped. No output is provided.
578
inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
579
if no more input was provided, Z_DATA_ERROR if no flush point has been found,
580
or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
581
case, the application may save the current current value of total_in which
582
indicates where valid compressed data was found. In the error case, the
583
application may repeatedly call inflateSync, providing more input each time,
584
until success or end of the input data.
587
ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
589
This function is equivalent to inflateEnd followed by inflateInit,
590
but does not free and reallocate all the internal decompression state.
591
The stream will keep attributes that may have been set by inflateInit2.
593
inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
594
stream state was inconsistent (such as zalloc or state being NULL).
598
/* utility functions */
601
The following utility functions are implemented on top of the
602
basic stream-oriented functions. To simplify the interface, some
603
default options are assumed (compression level and memory usage,
604
standard memory allocation functions). The source code of these
605
utility functions can easily be modified if you need special options.
608
ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
609
const Bytef *source, uLong sourceLen));
611
Compresses the source buffer into the destination buffer. sourceLen is
612
the byte length of the source buffer. Upon entry, destLen is the total
613
size of the destination buffer, which must be at least 0.1% larger than
614
sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
616
This function can be used to compress a whole file at once if the
617
input file is mmap'ed.
618
compress returns Z_OK if success, Z_MEM_ERROR if there was not
619
enough memory, Z_BUF_ERROR if there was not enough room in the output
623
ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
624
const Bytef *source, uLong sourceLen,
627
Compresses the source buffer into the destination buffer. The level
628
parameter has the same meaning as in deflateInit. sourceLen is the byte
629
length of the source buffer. Upon entry, destLen is the total size of the
630
destination buffer, which must be at least 0.1% larger than sourceLen plus
631
12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
633
compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
634
memory, Z_BUF_ERROR if there was not enough room in the output buffer,
635
Z_STREAM_ERROR if the level parameter is invalid.
638
ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
639
const Bytef *source, uLong sourceLen));
641
Decompresses the source buffer into the destination buffer. sourceLen is
642
the byte length of the source buffer. Upon entry, destLen is the total
643
size of the destination buffer, which must be large enough to hold the
644
entire uncompressed data. (The size of the uncompressed data must have
645
been saved previously by the compressor and transmitted to the decompressor
646
by some mechanism outside the scope of this compression library.)
647
Upon exit, destLen is the actual size of the compressed buffer.
648
This function can be used to decompress a whole file at once if the
649
input file is mmap'ed.
651
uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
652
enough memory, Z_BUF_ERROR if there was not enough room in the output
653
buffer, or Z_DATA_ERROR if the input data was corrupted.
657
typedef voidp gzFile;
659
ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
661
Opens a gzip (.gz) file for reading or writing. The mode parameter
662
is as in fopen ("rb" or "wb") but can also include a compression level
663
("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
664
Huffman only compression as in "wb1h". (See the description
665
of deflateInit2 for more information about the strategy parameter.)
667
gzopen can be used to read a file which is not in gzip format; in this
668
case gzread will directly read from the file without decompression.
670
gzopen returns NULL if the file could not be opened or if there was
671
insufficient memory to allocate the (de)compression state; errno
672
can be checked to distinguish the two cases (if errno is zero, the
673
zlib error is Z_MEM_ERROR). */
675
ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
677
gzdopen() associates a gzFile with the file descriptor fd. File
678
descriptors are obtained from calls like open, dup, creat, pipe or
679
fileno (in the file has been previously opened with fopen).
680
The mode parameter is as in gzopen.
681
The next call of gzclose on the returned gzFile will also close the
682
file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
683
descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
684
gzdopen returns NULL if there was insufficient memory to allocate
685
the (de)compression state.
688
ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
690
Dynamically update the compression level or strategy. See the description
691
of deflateInit2 for the meaning of these parameters.
692
gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
696
ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
698
Reads the given number of uncompressed bytes from the compressed file.
699
If the input file was not in gzip format, gzread copies the given number
700
of bytes into the buffer.
701
gzread returns the number of uncompressed bytes actually read (0 for
702
end of file, -1 for error). */
704
ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
705
const voidp buf, unsigned len));
707
Writes the given number of uncompressed bytes into the compressed file.
708
gzwrite returns the number of uncompressed bytes actually written
709
(0 in case of error).
712
ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
714
Converts, formats, and writes the args to the compressed file under
715
control of the format string, as in fprintf. gzprintf returns the number of
716
uncompressed bytes actually written (0 in case of error).
719
ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
721
Writes the given null-terminated string to the compressed file, excluding
722
the terminating null character.
723
gzputs returns the number of characters written, or -1 in case of error.
726
ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
728
Reads bytes from the compressed file until len-1 characters are read, or
729
a newline character is read and transferred to buf, or an end-of-file
730
condition is encountered. The string is then terminated with a null
732
gzgets returns buf, or Z_NULL in case of error.
735
ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
737
Writes c, converted to an unsigned char, into the compressed file.
738
gzputc returns the value that was written, or -1 in case of error.
741
ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
743
Reads one byte from the compressed file. gzgetc returns this byte
744
or -1 in case of end of file or error.
747
ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
749
Flushes all pending output into the compressed file. The parameter
750
flush is as in the deflate() function. The return value is the zlib
751
error number (see function gzerror below). gzflush returns Z_OK if
752
the flush parameter is Z_FINISH and all output could be flushed.
753
gzflush should be called only when strictly necessary because it can
757
ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
758
z_off_t offset, int whence));
760
Sets the starting position for the next gzread or gzwrite on the
761
given compressed file. The offset represents a number of bytes in the
762
uncompressed data stream. The whence parameter is defined as in lseek(2);
763
the value SEEK_END is not supported.
764
If the file is opened for reading, this function is emulated but can be
765
extremely slow. If the file is opened for writing, only forward seeks are
766
supported; gzseek then compresses a sequence of zeroes up to the new
769
gzseek returns the resulting offset location as measured in bytes from
770
the beginning of the uncompressed stream, or -1 in case of error, in
771
particular if the file is opened for writing and the new starting position
772
would be before the current position.
775
ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
777
Rewinds the given file. This function is supported only for reading.
779
gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
782
ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
784
Returns the starting position for the next gzread or gzwrite on the
785
given compressed file. This position represents a number of bytes in the
786
uncompressed data stream.
788
gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
791
ZEXTERN int ZEXPORT gzeof OF((gzFile file));
793
Returns 1 when EOF has previously been detected reading the given
794
input stream, otherwise zero.
797
ZEXTERN int ZEXPORT gzclose OF((gzFile file));
799
Flushes all pending output if necessary, closes the compressed file
800
and deallocates all the (de)compression state. The return value is the zlib
801
error number (see function gzerror below).
804
ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
806
Returns the error message for the last error which occurred on the
807
given compressed file. errnum is set to zlib error number. If an
808
error occurred in the file system and not in the compression library,
809
errnum is set to Z_ERRNO and the application may consult errno
810
to get the exact error code.
813
/* checksum functions */
816
These functions are not related to compression but are exported
817
anyway because they might be useful in applications using the
821
ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
824
Update a running Adler-32 checksum with the bytes buf[0..len-1] and
825
return the updated checksum. If buf is NULL, this function returns
826
the required initial value for the checksum.
827
An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
828
much faster. Usage example:
830
uLong adler = adler32(0L, Z_NULL, 0);
832
while (read_buffer(buffer, length) != EOF) {
833
adler = adler32(adler, buffer, length);
835
if (adler != original_adler) error();
838
ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
840
Update a running crc with the bytes buf[0..len-1] and return the updated
841
crc. If buf is NULL, this function returns the required initial value
842
for the crc. Pre- and post-conditioning (one's complement) is performed
843
within this function so it shouldn't be done by the application.
846
uLong crc = crc32(0L, Z_NULL, 0);
848
while (read_buffer(buffer, length) != EOF) {
849
crc = crc32(crc, buffer, length);
851
if (crc != original_crc) error();
855
/* various hacks, don't look :) */
857
/* deflateInit and inflateInit are macros to allow checking the zlib version
858
* and the compiler's view of z_stream:
860
ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
861
const char *version, int stream_size));
862
ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
863
const char *version, int stream_size));
864
ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
865
int windowBits, int memLevel,
866
int strategy, const char *version,
868
ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
869
const char *version, int stream_size));
870
#define deflateInit(strm, level) \
871
deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
872
#define inflateInit(strm) \
873
inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
874
#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
875
deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
876
(strategy), ZLIB_VERSION, sizeof(z_stream))
877
#define inflateInit2(strm, windowBits) \
878
inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
881
#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
882
struct internal_state {int dummy;}; /* hack for buggy compilers */
885
ZEXTERN const char * ZEXPORT zError OF((int err));
886
ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
887
ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
added
removed
cutestuff/zip/minizip/win32/zlib.h
