40
#define ZLIB_VERSION "1.2.3"
41
#define ZLIB_VERNUM 0x1230
40
#define ZLIB_VERSION "1.2.5"
41
#define ZLIB_VERNUM 0x1250
42
#define ZLIB_VER_MAJOR 1
43
#define ZLIB_VER_MINOR 2
44
#define ZLIB_VER_REVISION 5
45
#define ZLIB_VER_SUBREVISION 0
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
The 'zlib' compression library provides in-memory compression and
49
decompression functions, including integrity checks of the uncompressed data.
50
This version of the library supports only one compression method (deflation)
51
but other algorithms will be added later and will have the same stream
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
Compression can be done in a single step if the buffers are large enough,
55
or can be done by repeated calls of the compression function. In the latter
56
case, the application must provide more input and/or consume the output
54
57
(providing more output space) before each call.
56
The compressed data format used by default by the in-memory functions is
59
The compressed data format used by default by the in-memory functions is
57
60
the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
58
61
around a deflate stream, which is itself documented in RFC 1951.
60
The library also supports reading and writing files in gzip (.gz) format
63
The library also supports reading and writing files in gzip (.gz) format
61
64
with an interface similar to that of stdio using the functions that start
62
65
with "gz". The gzip format is different from the zlib format. gzip is a
63
66
gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
65
This library can optionally read and write gzip streams in memory as well.
68
This library can optionally read and write gzip streams in memory as well.
67
The zlib format was designed to be compact and fast for use in memory
70
The zlib format was designed to be compact and fast for use in memory
68
71
and on communications channels. The gzip format was designed for single-
69
72
file compression on file systems, has a larger header than zlib to maintain
70
73
directory information, and uses a different, slower check method than zlib.
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
The library does not install any signal handler. The decoder checks
76
the consistency of the compressed data, so the library should never crash
77
even in case of corrupted input.
77
80
typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
126
129
typedef gz_header FAR *gz_headerp;
129
The application must update next_in and avail_in when avail_in has
130
dropped to zero. It must update next_out and avail_out when avail_out
131
has dropped to zero. The application must initialize zalloc, zfree and
132
opaque before calling the init function. All other fields are set by the
133
compression library and must not be updated by the application.
132
The application must update next_in and avail_in when avail_in has dropped
133
to zero. It must update next_out and avail_out when avail_out has dropped
134
to zero. The application must initialize zalloc, zfree and opaque before
135
calling the init function. All other fields are set by the compression
136
library and must not be updated by the application.
135
The opaque value provided by the application will be passed as the first
136
parameter for calls of zalloc and zfree. This can be useful for custom
137
memory management. The compression library attaches no meaning to the
138
The opaque value provided by the application will be passed as the first
139
parameter for calls of zalloc and zfree. This can be useful for custom
140
memory management. The compression library attaches no meaning to the
140
zalloc must return Z_NULL if there is not enough memory for the object.
143
zalloc must return Z_NULL if there is not enough memory for the object.
141
144
If zlib is used in a multi-threaded application, zalloc and zfree must be
144
On 16-bit systems, the functions zalloc and zfree must be able to allocate
145
exactly 65536 bytes, but will not be required to allocate more than this
146
if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
147
pointers returned by zalloc for objects of exactly 65536 bytes *must*
148
have their offset normalized to zero. The default allocation function
149
provided by this library ensures this (see zutil.c). To reduce memory
150
requirements and avoid any allocation of 64K objects, at the expense of
151
compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
147
On 16-bit systems, the functions zalloc and zfree must be able to allocate
148
exactly 65536 bytes, but will not be required to allocate more than this if
149
the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
150
returned by zalloc for objects of exactly 65536 bytes *must* have their
151
offset normalized to zero. The default allocation function provided by this
152
library ensures this (see zutil.c). To reduce memory requirements and avoid
153
any allocation of 64K objects, at the expense of compression ratio, compile
154
the library with -DMAX_WBITS=14 (see zconf.h).
153
The fields total_in and total_out can be used for statistics or
154
progress reports. After compression, total_in holds the total size of
155
the uncompressed data and may be saved for use in the decompressor
156
(particularly if the decompressor wants to decompress everything in
156
The fields total_in and total_out can be used for statistics or progress
157
reports. After compression, total_in holds the total size of the
158
uncompressed data and may be saved for use in the decompressor (particularly
159
if the decompressor wants to decompress everything in a single step).
162
164
#define Z_NO_FLUSH 0
163
#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
165
#define Z_PARTIAL_FLUSH 1
164
166
#define Z_SYNC_FLUSH 2
165
167
#define Z_FULL_FLUSH 3
166
168
#define Z_FINISH 4
167
169
#define Z_BLOCK 5
168
171
/* Allowed flush values; see deflate() and inflate() below for details */
207
210
#define zlib_version zlibVersion()
208
211
/* for compatibility with versions < 1.0.2 */
210
214
/* basic functions */
212
216
ZEXTERN const char * ZEXPORT zlibVersion OF((void));
213
217
/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
214
If the first character differs, the library code actually used is
215
not compatible with the zlib.h header file used by the application.
216
This check is automatically made by deflateInit and inflateInit.
218
If the first character differs, the library code actually used is not
219
compatible with the zlib.h header file used by the application. This check
220
is automatically made by deflateInit and inflateInit.
220
224
ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
222
Initializes the internal stream state for compression. The fields
223
zalloc, zfree and opaque must be initialized before by the caller.
224
If zalloc and zfree are set to Z_NULL, deflateInit updates them to
225
use default allocation functions.
226
Initializes the internal stream state for compression. The fields
227
zalloc, zfree and opaque must be initialized before by the caller. If
228
zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
229
allocation functions.
227
231
The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
228
1 gives best speed, 9 gives best compression, 0 gives no compression at
229
all (the input data is simply copied a block at a time).
230
Z_DEFAULT_COMPRESSION requests a default compromise between speed and
231
compression (currently equivalent to level 6).
232
1 gives best speed, 9 gives best compression, 0 gives no compression at all
233
(the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
234
requests a default compromise between speed and compression (currently
235
equivalent to level 6).
233
deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
234
enough memory, Z_STREAM_ERROR if level is not a valid compression level,
237
deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
238
memory, Z_STREAM_ERROR if level is not a valid compression level, or
235
239
Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
236
with the version assumed by the caller (ZLIB_VERSION).
237
msg is set to null if there is no error message. deflateInit does not
238
perform any compression: this will be done by deflate().
240
with the version assumed by the caller (ZLIB_VERSION). msg is set to null
241
if there is no error message. deflateInit does not perform any compression:
242
this will be done by deflate().
242
246
ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
244
248
deflate compresses as much data as possible, and stops when the input
245
buffer becomes empty or the output buffer becomes full. It may introduce some
246
output latency (reading input without producing any output) except when
249
buffer becomes empty or the output buffer becomes full. It may introduce
250
some output latency (reading input without producing any output) except when
249
The detailed semantics are as follows. deflate performs one or both of the
253
The detailed semantics are as follows. deflate performs one or both of the
250
254
following actions:
252
256
- Compress more input starting at next_in and update next_in and avail_in
253
accordingly. If not all input can be processed (because there is not
257
accordingly. If not all input can be processed (because there is not
254
258
enough room in the output buffer), next_in and avail_in are updated and
255
259
processing will resume at this point for the next call of deflate().
257
261
- Provide more output starting at next_out and update next_out and avail_out
258
accordingly. This action is forced if the parameter flush is non zero.
262
accordingly. This action is forced if the parameter flush is non zero.
259
263
Forcing flush frequently degrades the compression ratio, so this parameter
260
should be set only when necessary (in interactive applications).
261
Some output may be provided even if flush is not set.
264
should be set only when necessary (in interactive applications). Some
265
output may be provided even if flush is not set.
263
Before the call of deflate(), the application should ensure that at least
264
one of the actions is possible, by providing more input and/or consuming
265
more output, and updating avail_in or avail_out accordingly; avail_out
266
should never be zero before the call. The application can consume the
267
compressed output when it wants, for example when the output buffer is full
268
(avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
269
and with zero avail_out, it must be called again after making room in the
270
output buffer because there might be more output pending.
267
Before the call of deflate(), the application should ensure that at least
268
one of the actions is possible, by providing more input and/or consuming more
269
output, and updating avail_in or avail_out accordingly; avail_out should
270
never be zero before the call. The application can consume the compressed
271
output when it wants, for example when the output buffer is full (avail_out
272
== 0), or after each call of deflate(). If deflate returns Z_OK and with
273
zero avail_out, it must be called again after making room in the output
274
buffer because there might be more output pending.
272
276
Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
273
decide how much data to accumualte before producing output, in order to
277
decide how much data to accumulate before producing output, in order to
274
278
maximize compression.
276
280
If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
277
281
flushed to the output buffer and the output is aligned on a byte boundary, so
278
that the decompressor can get all input data available so far. (In particular
279
avail_in is zero after the call if enough output space has been provided
280
before the call.) Flushing may degrade compression for some compression
281
algorithms and so it should be used only when necessary.
282
that the decompressor can get all input data available so far. (In
283
particular avail_in is zero after the call if enough output space has been
284
provided before the call.) Flushing may degrade compression for some
285
compression algorithms and so it should be used only when necessary. This
286
completes the current deflate block and follows it with an empty stored block
287
that is three bits plus filler bits to the next byte, followed by four bytes
290
If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
291
output buffer, but the output is not aligned to a byte boundary. All of the
292
input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
293
This completes the current deflate block and follows it with an empty fixed
294
codes block that is 10 bits long. This assures that enough bytes are output
295
in order for the decompressor to finish the block before the empty fixed code
298
If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
299
for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
300
seven bits of the current block are held to be written as the next byte after
301
the next deflate block is completed. In this case, the decompressor may not
302
be provided enough bits at this point in order to complete decompression of
303
the data provided so far to the compressor. It may need to wait for the next
304
block to be emitted. This is for advanced applications that need to control
305
the emission of deflate blocks.
283
307
If flush is set to Z_FULL_FLUSH, all output is flushed as with
284
308
Z_SYNC_FLUSH, and the compression state is reset so that decompression can
285
309
restart from this point if previous compressed data has been damaged or if
286
random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
310
random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
289
313
If deflate returns with avail_out == 0, this function must be called again
290
314
with the same value of the flush parameter and more output space (updated
291
315
avail_out), until the flush is complete (deflate returns with non-zero
292
avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
316
avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
293
317
avail_out is greater than six to avoid repeated flush markers due to
294
318
avail_out == 0 on return.
296
320
If the parameter flush is set to Z_FINISH, pending input is processed,
297
pending output is flushed and deflate returns with Z_STREAM_END if there
298
was enough output space; if deflate returns with Z_OK, this function must be
321
pending output is flushed and deflate returns with Z_STREAM_END if there was
322
enough output space; if deflate returns with Z_OK, this function must be
299
323
called again with Z_FINISH and more output space (updated avail_out) but no
300
more input data, until it returns with Z_STREAM_END or an error. After
301
deflate has returned Z_STREAM_END, the only possible operations on the
302
stream are deflateReset or deflateEnd.
324
more input data, until it returns with Z_STREAM_END or an error. After
325
deflate has returned Z_STREAM_END, the only possible operations on the stream
326
are deflateReset or deflateEnd.
304
328
Z_FINISH can be used immediately after deflateInit if all the compression
305
is to be done in a single step. In this case, avail_out must be at least
306
the value returned by deflateBound (see below). If deflate does not return
329
is to be done in a single step. In this case, avail_out must be at least the
330
value returned by deflateBound (see below). If deflate does not return
307
331
Z_STREAM_END, then it must be called again as described above.
309
333
deflate() sets strm->adler to the adler32 checksum of all input read
310
334
so far (that is, total_in bytes).
312
336
deflate() may update strm->data_type if it can make a good guess about
313
the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
314
binary. This field is only for information purposes and does not affect
315
the compression algorithm in any manner.
337
the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
338
binary. This field is only for information purposes and does not affect the
339
compression algorithm in any manner.
317
341
deflate() returns Z_OK if some progress has been made (more input
318
342
processed or more output produced), Z_STREAM_END if all input has been
319
343
consumed and all output has been produced (only when flush is set to
320
344
Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
321
if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
322
(for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
345
if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
346
(for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
323
347
fatal, and deflate() can be called again with more input and more output
324
348
space to continue compressing.
354
378
inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
355
379
memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
356
version assumed by the caller. msg is set to null if there is no error
357
message. inflateInit does not perform any decompression apart from reading
358
the zlib header if present: this will be done by inflate(). (So next_in and
359
avail_in may be modified, but next_out and avail_out are unchanged.)
380
version assumed by the caller, or Z_STREAM_ERROR if the parameters are
381
invalid, such as a null pointer to the structure. msg is set to null if
382
there is no error message. inflateInit does not perform any decompression
383
apart from possibly reading the zlib header if present: actual decompression
384
will be done by inflate(). (So next_in and avail_in may be modified, but
385
next_out and avail_out are unused and unchanged.) The current implementation
386
of inflateInit() does not process any header information -- that is deferred
387
until inflate() is called.
363
391
ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
365
393
inflate decompresses as much data as possible, and stops when the input
366
buffer becomes empty or the output buffer becomes full. It may introduce
394
buffer becomes empty or the output buffer becomes full. It may introduce
367
395
some output latency (reading input without producing any output) except when
370
The detailed semantics are as follows. inflate performs one or both of the
398
The detailed semantics are as follows. inflate performs one or both of the
371
399
following actions:
373
401
- Decompress more input starting at next_in and update next_in and avail_in
374
accordingly. If not all input can be processed (because there is not
375
enough room in the output buffer), next_in is updated and processing
376
will resume at this point for the next call of inflate().
402
accordingly. If not all input can be processed (because there is not
403
enough room in the output buffer), next_in is updated and processing will
404
resume at this point for the next call of inflate().
378
406
- Provide more output starting at next_out and update next_out and avail_out
379
accordingly. inflate() provides as much output as possible, until there
380
is no more input data or no more space in the output buffer (see below
381
about the flush parameter).
383
Before the call of inflate(), the application should ensure that at least
384
one of the actions is possible, by providing more input and/or consuming
385
more output, and updating the next_* and avail_* values accordingly.
386
The application can consume the uncompressed output when it wants, for
387
example when the output buffer is full (avail_out == 0), or after each
388
call of inflate(). If inflate returns Z_OK and with zero avail_out, it
389
must be called again after making room in the output buffer because there
390
might be more output pending.
392
The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
393
Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
394
output as possible to the output buffer. Z_BLOCK requests that inflate() stop
395
if and when it gets to the next deflate block boundary. When decoding the
396
zlib or gzip format, this will cause inflate() to return immediately after
397
the header and before the first block. When doing a raw inflate, inflate()
398
will go ahead and process the first block, and will return when it gets to
399
the end of that block, or when it runs out of data.
407
accordingly. inflate() provides as much output as possible, until there is
408
no more input data or no more space in the output buffer (see below about
409
the flush parameter).
411
Before the call of inflate(), the application should ensure that at least
412
one of the actions is possible, by providing more input and/or consuming more
413
output, and updating the next_* and avail_* values accordingly. The
414
application can consume the uncompressed output when it wants, for example
415
when the output buffer is full (avail_out == 0), or after each call of
416
inflate(). If inflate returns Z_OK and with zero avail_out, it must be
417
called again after making room in the output buffer because there might be
420
The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
421
Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
422
output as possible to the output buffer. Z_BLOCK requests that inflate()
423
stop if and when it gets to the next deflate block boundary. When decoding
424
the zlib or gzip format, this will cause inflate() to return immediately
425
after the header and before the first block. When doing a raw inflate,
426
inflate() will go ahead and process the first block, and will return when it
427
gets to the end of that block, or when it runs out of data.
401
429
The Z_BLOCK option assists in appending to or combining deflate streams.
402
430
Also to assist in this, on return inflate() will set strm->data_type to the
403
number of unused bits in the last byte taken from strm->next_in, plus 64
404
if inflate() is currently decoding the last block in the deflate stream,
405
plus 128 if inflate() returned immediately after decoding an end-of-block
406
code or decoding the complete header up to just before the first byte of the
407
deflate stream. The end-of-block will not be indicated until all of the
408
uncompressed data from that block has been written to strm->next_out. The
409
number of unused bits may in general be greater than seven, except when
410
bit 7 of data_type is set, in which case the number of unused bits will be
431
number of unused bits in the last byte taken from strm->next_in, plus 64 if
432
inflate() is currently decoding the last block in the deflate stream, plus
433
128 if inflate() returned immediately after decoding an end-of-block code or
434
decoding the complete header up to just before the first byte of the deflate
435
stream. The end-of-block will not be indicated until all of the uncompressed
436
data from that block has been written to strm->next_out. The number of
437
unused bits may in general be greater than seven, except when bit 7 of
438
data_type is set, in which case the number of unused bits will be less than
439
eight. data_type is set as noted here every time inflate() returns for all
440
flush options, and so can be used to determine the amount of currently
441
consumed input in bits.
443
The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
444
end of each deflate block header is reached, before any actual data in that
445
block is decoded. This allows the caller to determine the length of the
446
deflate block header for later use in random access within a deflate block.
447
256 is added to the value of strm->data_type when inflate() returns
448
immediately after reaching the end of the deflate block header.
413
450
inflate() should normally be called until it returns Z_STREAM_END or an
414
error. However if all decompression is to be performed in a single step
415
(a single call of inflate), the parameter flush should be set to
416
Z_FINISH. In this case all pending input is processed and all pending
417
output is flushed; avail_out must be large enough to hold all the
418
uncompressed data. (The size of the uncompressed data may have been saved
419
by the compressor for this purpose.) The next operation on this stream must
420
be inflateEnd to deallocate the decompression state. The use of Z_FINISH
421
is never required, but can be used to inform inflate that a faster approach
422
may be used for the single inflate() call.
451
error. However if all decompression is to be performed in a single step (a
452
single call of inflate), the parameter flush should be set to Z_FINISH. In
453
this case all pending input is processed and all pending output is flushed;
454
avail_out must be large enough to hold all the uncompressed data. (The size
455
of the uncompressed data may have been saved by the compressor for this
456
purpose.) The next operation on this stream must be inflateEnd to deallocate
457
the decompression state. The use of Z_FINISH is never required, but can be
458
used to inform inflate that a faster approach may be used for the single
424
461
In this implementation, inflate() always flushes as much output as
425
462
possible to the output buffer, and always uses the faster approach on the
426
first call. So the only effect of the flush parameter in this implementation
463
first call. So the only effect of the flush parameter in this implementation
427
464
is on the return value of inflate(), as noted below, or when it returns early
428
because Z_BLOCK is used.
465
because Z_BLOCK or Z_TREES is used.
430
467
If a preset dictionary is needed after this call (see inflateSetDictionary
431
468
below), inflate sets strm->adler to the adler32 checksum of the dictionary
432
469
chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
433
470
strm->adler to the adler32 checksum of all output produced so far (that is,
434
471
total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
435
below. At the end of the stream, inflate() checks that its computed adler32
472
below. At the end of the stream, inflate() checks that its computed adler32
436
473
checksum is equal to that saved by the compressor and returns Z_STREAM_END
437
474
only if the checksum is correct.
439
inflate() will decompress and check either zlib-wrapped or gzip-wrapped
440
deflate data. The header type is detected automatically. Any information
441
contained in the gzip header is not retained, so applications that need that
442
information should instead use raw inflate, see inflateInit2() below, or
443
inflateBack() and perform their own processing of the gzip header and
476
inflate() can decompress and check either zlib-wrapped or gzip-wrapped
477
deflate data. The header type is detected automatically, if requested when
478
initializing with inflateInit2(). Any information contained in the gzip
479
header is not retained, so applications that need that information should
480
instead use raw inflate, see inflateInit2() below, or inflateBack() and
481
perform their own processing of the gzip header and trailer.
446
483
inflate() returns Z_OK if some progress has been made (more input processed
447
484
or more output produced), Z_STREAM_END if the end of the compressed data has
487
This is another version of deflateInit with more compression options. The
488
fields next_in, zalloc, zfree and opaque must be initialized before by
525
This is another version of deflateInit with more compression options. The
526
fields next_in, zalloc, zfree and opaque must be initialized before by the
491
The method parameter is the compression method. It must be Z_DEFLATED in
529
The method parameter is the compression method. It must be Z_DEFLATED in
492
530
this version of the library.
494
532
The windowBits parameter is the base two logarithm of the window size
495
(the size of the history buffer). It should be in the range 8..15 for this
496
version of the library. Larger values of this parameter result in better
497
compression at the expense of memory usage. The default value is 15 if
533
(the size of the history buffer). It should be in the range 8..15 for this
534
version of the library. Larger values of this parameter result in better
535
compression at the expense of memory usage. The default value is 15 if
498
536
deflateInit is used instead.
500
windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
501
determines the window size. deflate() will then generate raw deflate data
538
windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
539
determines the window size. deflate() will then generate raw deflate data
502
540
with no zlib header or trailer, and will not compute an adler32 check value.
504
windowBits can also be greater than 15 for optional gzip encoding. Add
542
windowBits can also be greater than 15 for optional gzip encoding. Add
505
543
16 to windowBits to write a simple gzip header and trailer around the
506
compressed data instead of a zlib wrapper. The gzip header will have no
507
file name, no extra data, no comment, no modification time (set to zero),
508
no header crc, and the operating system will be set to 255 (unknown). If a
544
compressed data instead of a zlib wrapper. The gzip header will have no
545
file name, no extra data, no comment, no modification time (set to zero), no
546
header crc, and the operating system will be set to 255 (unknown). If a
509
547
gzip stream is being written, strm->adler is a crc32 instead of an adler32.
511
549
The memLevel parameter specifies how much memory should be allocated
512
for the internal compression state. memLevel=1 uses minimum memory but
513
is slow and reduces compression ratio; memLevel=9 uses maximum memory
514
for optimal speed. The default value is 8. See zconf.h for total memory
515
usage as a function of windowBits and memLevel.
550
for the internal compression state. memLevel=1 uses minimum memory but is
551
slow and reduces compression ratio; memLevel=9 uses maximum memory for
552
optimal speed. The default value is 8. See zconf.h for total memory usage
553
as a function of windowBits and memLevel.
517
The strategy parameter is used to tune the compression algorithm. Use the
555
The strategy parameter is used to tune the compression algorithm. Use the
518
556
value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
519
557
filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
520
558
string match), or Z_RLE to limit match distances to one (run-length
521
encoding). Filtered data consists mostly of small values with a somewhat
522
random distribution. In this case, the compression algorithm is tuned to
523
compress them better. The effect of Z_FILTERED is to force more Huffman
559
encoding). Filtered data consists mostly of small values with a somewhat
560
random distribution. In this case, the compression algorithm is tuned to
561
compress them better. The effect of Z_FILTERED is to force more Huffman
524
562
coding and less string matching; it is somewhat intermediate between
525
Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
526
Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
527
parameter only affects the compression ratio but not the correctness of the
528
compressed output even if it is not set appropriately. Z_FIXED prevents the
529
use of dynamic Huffman codes, allowing for a simpler decoder for special
563
Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
564
fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
565
strategy parameter only affects the compression ratio but not the
566
correctness of the compressed output even if it is not set appropriately.
567
Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
568
decoder for special applications.
532
deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
533
memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
534
method). msg is set to null if there is no error message. deflateInit2 does
535
not perform any compression: this will be done by deflate().
570
deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
571
memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
572
method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
573
incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
574
set to null if there is no error message. deflateInit2 does not perform any
575
compression: this will be done by deflate().
538
578
ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
540
580
uInt dictLength));
542
582
Initializes the compression dictionary from the given byte sequence
543
without producing any compressed output. This function must be called
544
immediately after deflateInit, deflateInit2 or deflateReset, before any
545
call of deflate. The compressor and decompressor must use exactly the same
583
without producing any compressed output. This function must be called
584
immediately after deflateInit, deflateInit2 or deflateReset, before any call
585
of deflate. The compressor and decompressor must use exactly the same
546
586
dictionary (see inflateSetDictionary).
548
588
The dictionary should consist of strings (byte sequences) that are likely
549
589
to be encountered later in the data to be compressed, with the most commonly
550
used strings preferably put towards the end of the dictionary. Using a
590
used strings preferably put towards the end of the dictionary. Using a
551
591
dictionary is most useful when the data to be compressed is short and can be
552
592
predicted with good accuracy; the data can then be compressed better than
553
593
with the default empty dictionary.
555
595
Depending on the size of the compression data structures selected by
556
596
deflateInit or deflateInit2, a part of the dictionary may in effect be
557
discarded, for example if the dictionary is larger than the window size in
558
deflate or deflate2. Thus the strings most likely to be useful should be
559
put at the end of the dictionary, not at the front. In addition, the
560
current implementation of deflate will use at most the window size minus
561
262 bytes of the provided dictionary.
597
discarded, for example if the dictionary is larger than the window size
598
provided in deflateInit or deflateInit2. Thus the strings most likely to be
599
useful should be put at the end of the dictionary, not at the front. In
600
addition, the current implementation of deflate will use at most the window
601
size minus 262 bytes of the provided dictionary.
563
603
Upon return of this function, strm->adler is set to the adler32 value
564
604
of the dictionary; the decompressor may later use this value to determine
565
which dictionary has been used by the compressor. (The adler32 value
605
which dictionary has been used by the compressor. (The adler32 value
566
606
applies to the whole dictionary even if only a subset of the dictionary is
567
607
actually used by the compressor.) If a raw deflate was requested, then the
568
608
adler32 value is not computed and strm->adler is not set.
570
610
deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
571
parameter is invalid (such as NULL dictionary) or the stream state is
611
parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
572
612
inconsistent (for example if deflate has already been called for this stream
573
or if the compression method is bsort). deflateSetDictionary does not
613
or if the compression method is bsort). deflateSetDictionary does not
574
614
perform any compression: this will be done by deflate().
694
735
ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
695
736
int windowBits));
697
This is another version of inflateInit with an extra parameter. The
738
This is another version of inflateInit with an extra parameter. The
698
739
fields next_in, avail_in, zalloc, zfree and opaque must be initialized
699
740
before by the caller.
701
742
The windowBits parameter is the base two logarithm of the maximum window
702
743
size (the size of the history buffer). It should be in the range 8..15 for
703
this version of the library. The default value is 15 if inflateInit is used
704
instead. windowBits must be greater than or equal to the windowBits value
744
this version of the library. The default value is 15 if inflateInit is used
745
instead. windowBits must be greater than or equal to the windowBits value
705
746
provided to deflateInit2() while compressing, or it must be equal to 15 if
706
deflateInit2() was not used. If a compressed stream with a larger window
747
deflateInit2() was not used. If a compressed stream with a larger window
707
748
size is given as input, inflate() will return with the error code
708
749
Z_DATA_ERROR instead of trying to allocate a larger window.
710
windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
711
determines the window size. inflate() will then process raw deflate data,
751
windowBits can also be zero to request that inflate use the window size in
752
the zlib header of the compressed stream.
754
windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
755
determines the window size. inflate() will then process raw deflate data,
712
756
not looking for a zlib or gzip header, not generating a check value, and not
713
looking for any check values for comparison at the end of the stream. This
757
looking for any check values for comparison at the end of the stream. This
714
758
is for use with other formats that use the deflate compressed data format
715
such as zip. Those formats provide their own check values. If a custom
759
such as zip. Those formats provide their own check values. If a custom
716
760
format is developed using the raw deflate format for compressed data, it is
717
761
recommended that a check value such as an adler32 or a crc32 be applied to
718
762
the uncompressed data as is done in the zlib, gzip, and zip formats. For
719
most applications, the zlib format should be used as is. Note that comments
763
most applications, the zlib format should be used as is. Note that comments
720
764
above on the use in deflateInit2() applies to the magnitude of windowBits.
722
windowBits can also be greater than 15 for optional gzip decoding. Add
766
windowBits can also be greater than 15 for optional gzip decoding. Add
723
767
32 to windowBits to enable zlib and gzip decoding with automatic header
724
768
detection, or add 16 to decode only the gzip format (the zlib format will
725
return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
726
a crc32 instead of an adler32.
769
return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
770
crc32 instead of an adler32.
728
772
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
729
memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
730
is set to null if there is no error message. inflateInit2 does not perform
731
any decompression apart from reading the zlib header if present: this will
732
be done by inflate(). (So next_in and avail_in may be modified, but next_out
733
and avail_out are unchanged.)
773
memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
774
version assumed by the caller, or Z_STREAM_ERROR if the parameters are
775
invalid, such as a null pointer to the structure. msg is set to null if
776
there is no error message. inflateInit2 does not perform any decompression
777
apart from possibly reading the zlib header if present: actual decompression
778
will be done by inflate(). (So next_in and avail_in may be modified, but
779
next_out and avail_out are unused and unchanged.) The current implementation
780
of inflateInit2() does not process any header information -- that is
781
deferred until inflate() is called.
736
784
ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
803
863
This function inserts bits in the inflate input stream. The intent is
804
that this function is used to start inflating at a bit position in the
805
middle of a byte. The provided bits will be used before any bytes are used
806
from next_in. This function should only be used with raw inflate, and
807
should be used before the first inflate() call after inflateInit2() or
808
inflateReset(). bits must be less than or equal to 16, and that many of the
809
least significant bits of value will be inserted in the input.
811
inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
864
that this function is used to start inflating at a bit position in the
865
middle of a byte. The provided bits will be used before any bytes are used
866
from next_in. This function should only be used with raw inflate, and
867
should be used before the first inflate() call after inflateInit2() or
868
inflateReset(). bits must be less than or equal to 16, and that many of the
869
least significant bits of value will be inserted in the input.
871
If bits is negative, then the input stream bit buffer is emptied. Then
872
inflatePrime() can be called again to put bits in the buffer. This is used
873
to clear out bits leftover after feeding inflate a block description prior
874
to feeding inflate codes.
876
inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
812
877
stream state was inconsistent.
880
ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
882
This function returns two values, one in the lower 16 bits of the return
883
value, and the other in the remaining upper bits, obtained by shifting the
884
return value down 16 bits. If the upper value is -1 and the lower value is
885
zero, then inflate() is currently decoding information outside of a block.
886
If the upper value is -1 and the lower value is non-zero, then inflate is in
887
the middle of a stored block, with the lower value equaling the number of
888
bytes from the input remaining to copy. If the upper value is not -1, then
889
it is the number of bits back from the current bit position in the input of
890
the code (literal or length/distance pair) currently being processed. In
891
that case the lower value is the number of bytes already emitted for that
894
A code is being processed if inflate is waiting for more input to complete
895
decoding of the code, or if it has completed decoding but is waiting for
896
more output space to write the literal or match data.
898
inflateMark() is used to mark locations in the input data for random
899
access, which may be at bit positions, and to note those cases where the
900
output of a code may span boundaries of random access blocks. The current
901
location in the input stream can be determined from avail_in and data_type
902
as noted in the description for the Z_BLOCK flush parameter for inflate.
904
inflateMark returns the value noted above or -1 << 16 if the provided
905
source stream state was inconsistent.
815
908
ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
816
909
gz_headerp head));
818
inflateGetHeader() requests that gzip header information be stored in the
911
inflateGetHeader() requests that gzip header information be stored in the
819
912
provided gz_header structure. inflateGetHeader() may be called after
820
913
inflateInit2() or inflateReset(), and before the first call of inflate().
821
914
As inflate() processes the gzip stream, head->done is zero until the header
822
915
is completed, at which time head->done is set to one. If a zlib stream is
823
916
being decoded, then head->done is set to -1 to indicate that there will be
824
no gzip header information forthcoming. Note that Z_BLOCK can be used to
825
force inflate() to return immediately after header processing is complete
826
and before any actual data is decompressed.
917
no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
918
used to force inflate() to return immediately after header processing is
919
complete and before any actual data is decompressed.
828
The text, time, xflags, and os fields are filled in with the gzip header
921
The text, time, xflags, and os fields are filled in with the gzip header
829
922
contents. hcrc is set to true if there is a header CRC. (The header CRC
830
was valid if done is set to one.) If extra is not Z_NULL, then extra_max
923
was valid if done is set to one.) If extra is not Z_NULL, then extra_max
831
924
contains the maximum number of bytes to write to extra. Once done is true,
832
925
extra_len contains the actual extra field length, and extra contains the
833
926
extra field, or that field truncated if extra_max is less than extra_len.
834
927
If name is not Z_NULL, then up to name_max characters are written there,
835
928
terminated with a zero unless the length is greater than name_max. If
836
929
comment is not Z_NULL, then up to comm_max characters are written there,
837
terminated with a zero unless the length is greater than comm_max. When
838
any of extra, name, or comment are not Z_NULL and the respective field is
839
not present in the header, then that field is set to Z_NULL to signal its
930
terminated with a zero unless the length is greater than comm_max. When any
931
of extra, name, or comment are not Z_NULL and the respective field is not
932
present in the header, then that field is set to Z_NULL to signal its
840
933
absence. This allows the use of deflateSetHeader() with the returned
841
934
structure to duplicate the header. However if those fields are set to
842
935
allocated memory, then the application will need to save those pointers
843
936
elsewhere so that they can be eventually freed.
845
If inflateGetHeader is not used, then the header information is simply
938
If inflateGetHeader is not used, then the header information is simply
846
939
discarded. The header is always checked for validity, including the header
847
940
CRC if present. inflateReset() will reset the process to discard the header
848
941
information. The application would need to call inflateGetHeader() again to
849
942
retrieve the header from the next gzip stream.
851
inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
944
inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
852
945
stream state was inconsistent.
1066
typedef voidp gzFile;
1068
ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1070
Opens a gzip (.gz) file for reading or writing. The mode parameter
1071
is as in fopen ("rb" or "wb") but can also include a compression level
1072
("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
1073
Huffman only compression as in "wb1h", or 'R' for run-length encoding
1074
as in "wb1R". (See the description of deflateInit2 for more information
1075
about the strategy parameter.)
1156
/* gzip file access functions */
1159
This library supports reading and writing files in gzip (.gz) format with
1160
an interface similar to that of stdio, using the functions that start with
1161
"gz". The gzip format is different from the zlib format. gzip is a gzip
1162
wrapper, documented in RFC 1952, wrapped around a deflate stream.
1165
typedef voidp gzFile; /* opaque gzip file descriptor */
1168
ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1170
Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1171
in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1172
a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1173
compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1174
for fixed code compression as in "wb9F". (See the description of
1175
deflateInit2 for more information about the strategy parameter.) Also "a"
1176
can be used instead of "w" to request that the gzip stream that will be
1177
written be appended to the file. "+" will result in an error, since reading
1178
and writing to the same gzip file is not supported.
1077
1180
gzopen can be used to read a file which is not in gzip format; in this
1078
1181
case gzread will directly read from the file without decompression.
1080
gzopen returns NULL if the file could not be opened or if there was
1081
insufficient memory to allocate the (de)compression state; errno
1082
can be checked to distinguish the two cases (if errno is zero, the
1083
zlib error is Z_MEM_ERROR). */
1085
ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1087
gzdopen() associates a gzFile with the file descriptor fd. File
1088
descriptors are obtained from calls like open, dup, creat, pipe or
1089
fileno (in the file has been previously opened with fopen).
1090
The mode parameter is as in gzopen.
1091
The next call of gzclose on the returned gzFile will also close the
1092
file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
1093
descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
1094
gzdopen returns NULL if there was insufficient memory to allocate
1095
the (de)compression state.
1183
gzopen returns NULL if the file could not be opened, if there was
1184
insufficient memory to allocate the gzFile state, or if an invalid mode was
1185
specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1186
errno can be checked to determine if the reason gzopen failed was that the
1187
file could not be opened.
1190
ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1192
gzdopen associates a gzFile with the file descriptor fd. File descriptors
1193
are obtained from calls like open, dup, creat, pipe or fileno (if the file
1194
has been previously opened with fopen). The mode parameter is as in gzopen.
1196
The next call of gzclose on the returned gzFile will also close the file
1197
descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1198
fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1199
mode);. The duplicated descriptor should be saved to avoid a leak, since
1200
gzdopen does not close fd if it fails.
1202
gzdopen returns NULL if there was insufficient memory to allocate the
1203
gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1204
provided, or '+' was provided), or if fd is -1. The file descriptor is not
1205
used until the next gz* read, write, seek, or close operation, so gzdopen
1206
will not detect if fd is invalid (unless fd is -1).
1209
ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1211
Set the internal buffer size used by this library's functions. The
1212
default buffer size is 8192 bytes. This function must be called after
1213
gzopen() or gzdopen(), and before any other calls that read or write the
1214
file. The buffer memory allocation is always deferred to the first read or
1215
write. Two buffers are allocated, either both of the specified size when
1216
writing, or one of the specified size and the other twice that size when
1217
reading. A larger buffer size of, for example, 64K or 128K bytes will
1218
noticeably increase the speed of decompression (reading).
1220
The new buffer size also affects the maximum length for gzprintf().
1222
gzbuffer() returns 0 on success, or -1 on failure, such as being called
1098
1226
ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1100
Dynamically update the compression level or strategy. See the description
1228
Dynamically update the compression level or strategy. See the description
1101
1229
of deflateInit2 for the meaning of these parameters.
1102
1231
gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1103
1232
opened for writing.
1106
ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1235
ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1108
Reads the given number of uncompressed bytes from the compressed file.
1109
If the input file was not in gzip format, gzread copies the given number
1110
of bytes into the buffer.
1111
gzread returns the number of uncompressed bytes actually read (0 for
1112
end of file, -1 for error). */
1114
ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1115
voidpc buf, unsigned len));
1237
Reads the given number of uncompressed bytes from the compressed file. If
1238
the input file was not in gzip format, gzread copies the given number of
1239
bytes into the buffer.
1241
After reaching the end of a gzip stream in the input, gzread will continue
1242
to read, looking for another gzip stream, or failing that, reading the rest
1243
of the input file directly without decompression. The entire input file
1244
will be read if gzread is called until it returns less than the requested
1247
gzread returns the number of uncompressed bytes actually read, less than
1248
len for end of file, or -1 for error.
1251
ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1252
voidpc buf, unsigned len));
1117
1254
Writes the given number of uncompressed bytes into the compressed file.
1118
gzwrite returns the number of uncompressed bytes actually written
1119
(0 in case of error).
1255
gzwrite returns the number of uncompressed bytes written or 0 in case of
1122
ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
1259
ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
1124
Converts, formats, and writes the args to the compressed file under
1125
control of the format string, as in fprintf. gzprintf returns the number of
1126
uncompressed bytes actually written (0 in case of error). The number of
1127
uncompressed bytes written is limited to 4095. The caller should assure that
1128
this limit is not exceeded. If it is exceeded, then gzprintf() will return
1129
return an error (0) with nothing written. In this case, there may also be a
1130
buffer overflow with unpredictable consequences, which is possible only if
1131
zlib was compiled with the insecure functions sprintf() or vsprintf()
1132
because the secure snprintf() or vsnprintf() functions were not available.
1261
Converts, formats, and writes the arguments to the compressed file under
1262
control of the format string, as in fprintf. gzprintf returns the number of
1263
uncompressed bytes actually written, or 0 in case of error. The number of
1264
uncompressed bytes written is limited to 8191, or one less than the buffer
1265
size given to gzbuffer(). The caller should assure that this limit is not
1266
exceeded. If it is exceeded, then gzprintf() will return an error (0) with
1267
nothing written. In this case, there may also be a buffer overflow with
1268
unpredictable consequences, which is possible only if zlib was compiled with
1269
the insecure functions sprintf() or vsprintf() because the secure snprintf()
1270
or vsnprintf() functions were not available. This can be determined using
1135
1274
ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1137
Writes the given null-terminated string to the compressed file, excluding
1276
Writes the given null-terminated string to the compressed file, excluding
1138
1277
the terminating null character.
1139
gzputs returns the number of characters written, or -1 in case of error.
1279
gzputs returns the number of characters written, or -1 in case of error.
1142
1282
ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1144
Reads bytes from the compressed file until len-1 characters are read, or
1145
a newline character is read and transferred to buf, or an end-of-file
1146
condition is encountered. The string is then terminated with a null
1148
gzgets returns buf, or Z_NULL in case of error.
1151
ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1153
Writes c, converted to an unsigned char, into the compressed file.
1154
gzputc returns the value that was written, or -1 in case of error.
1157
ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1159
Reads one byte from the compressed file. gzgetc returns this byte
1160
or -1 in case of end of file or error.
1163
ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1165
Push one character back onto the stream to be read again later.
1166
Only one character of push-back is allowed. gzungetc() returns the
1167
character pushed, or -1 on failure. gzungetc() will fail if a
1168
character has been pushed but not read yet, or if c is -1. The pushed
1169
character will be discarded if the stream is repositioned with gzseek()
1173
ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1175
Flushes all pending output into the compressed file. The parameter
1176
flush is as in the deflate() function. The return value is the zlib
1177
error number (see function gzerror below). gzflush returns Z_OK if
1178
the flush parameter is Z_FINISH and all output could be flushed.
1179
gzflush should be called only when strictly necessary because it can
1180
degrade compression.
1183
ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1184
z_off_t offset, int whence));
1186
Sets the starting position for the next gzread or gzwrite on the
1187
given compressed file. The offset represents a number of bytes in the
1188
uncompressed data stream. The whence parameter is defined as in lseek(2);
1284
Reads bytes from the compressed file until len-1 characters are read, or a
1285
newline character is read and transferred to buf, or an end-of-file
1286
condition is encountered. If any characters are read or if len == 1, the
1287
string is terminated with a null character. If no characters are read due
1288
to an end-of-file or len < 1, then the buffer is left untouched.
1290
gzgets returns buf which is a null-terminated string, or it returns NULL
1291
for end-of-file or in case of error. If there was an error, the contents at
1292
buf are indeterminate.
1295
ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1297
Writes c, converted to an unsigned char, into the compressed file. gzputc
1298
returns the value that was written, or -1 in case of error.
1301
ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1303
Reads one byte from the compressed file. gzgetc returns this byte or -1
1304
in case of end of file or error.
1307
ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1309
Push one character back onto the stream to be read as the first character
1310
on the next read. At least one character of push-back is allowed.
1311
gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1312
fail if c is -1, and may fail if a character has been pushed but not read
1313
yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1314
output buffer size of pushed characters is allowed. (See gzbuffer above.)
1315
The pushed character will be discarded if the stream is repositioned with
1316
gzseek() or gzrewind().
1319
ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1321
Flushes all pending output into the compressed file. The parameter flush
1322
is as in the deflate() function. The return value is the zlib error number
1323
(see function gzerror below). gzflush is only permitted when writing.
1325
If the flush parameter is Z_FINISH, the remaining data is written and the
1326
gzip stream is completed in the output. If gzwrite() is called again, a new
1327
gzip stream will be started in the output. gzread() is able to read such
1328
concatented gzip streams.
1330
gzflush should be called only when strictly necessary because it will
1331
degrade compression if called too often.
1335
ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1336
z_off_t offset, int whence));
1338
Sets the starting position for the next gzread or gzwrite on the given
1339
compressed file. The offset represents a number of bytes in the
1340
uncompressed data stream. The whence parameter is defined as in lseek(2);
1189
1341
the value SEEK_END is not supported.
1190
1343
If the file is opened for reading, this function is emulated but can be
1191
extremely slow. If the file is opened for writing, only forward seeks are
1344
extremely slow. If the file is opened for writing, only forward seeks are
1192
1345
supported; gzseek then compresses a sequence of zeroes up to the new
1193
1346
starting position.
1195
gzseek returns the resulting offset location as measured in bytes from
1348
gzseek returns the resulting offset location as measured in bytes from
1196
1349
the beginning of the uncompressed stream, or -1 in case of error, in
1197
1350
particular if the file is opened for writing and the new starting position
1198
1351
would be before the current position.
1203
1356
Rewinds the given file. This function is supported only for reading.
1205
gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1358
gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1208
1362
ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1364
Returns the starting position for the next gzread or gzwrite on the given
1365
compressed file. This position represents a number of bytes in the
1366
uncompressed data stream, and is zero when starting, even if appending or
1367
reading a gzip stream from the middle of a file using gzdopen().
1369
gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1210
Returns the starting position for the next gzread or gzwrite on the
1211
given compressed file. This position represents a number of bytes in the
1212
uncompressed data stream.
1373
ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1214
gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1375
Returns the current offset in the file being read or written. This offset
1376
includes the count of bytes that precede the gzip stream, for example when
1377
appending or when using gzdopen() for reading. When reading, the offset
1378
does not include as yet unused buffered input. This information can be used
1379
for a progress indicator. On error, gzoffset() returns -1.
1217
1382
ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1219
Returns 1 when EOF has previously been detected reading the given
1220
input stream, otherwise zero.
1384
Returns true (1) if the end-of-file indicator has been set while reading,
1385
false (0) otherwise. Note that the end-of-file indicator is set only if the
1386
read tried to go past the end of the input, but came up short. Therefore,
1387
just like feof(), gzeof() may return false even if there is no more data to
1388
read, in the event that the last read request was for the exact number of
1389
bytes remaining in the input file. This will happen if the input file size
1390
is an exact multiple of the buffer size.
1392
If gzeof() returns true, then the read functions will return no more data,
1393
unless the end-of-file indicator is reset by gzclearerr() and the input file
1394
has grown since the previous end of file was detected.
1223
1397
ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1225
Returns 1 if file is being read directly without decompression, otherwise
1399
Returns true (1) if file is being copied directly while reading, or false
1400
(0) if file is a gzip stream being decompressed. This state can change from
1401
false to true while reading the input file if the end of a gzip stream is
1402
reached, but is followed by data that is not another gzip stream.
1404
If the input file is empty, gzdirect() will return true, since the input
1405
does not contain a gzip stream.
1407
If gzdirect() is used immediately after gzopen() or gzdopen() it will
1408
cause buffers to be allocated to allow reading the file to determine if it
1409
is a gzip file. Therefore if gzbuffer() is used, it should be called before
1229
1413
ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1231
Flushes all pending output if necessary, closes the compressed file
1232
and deallocates all the (de)compression state. The return value is the zlib
1233
error number (see function gzerror below).
1415
Flushes all pending output if necessary, closes the compressed file and
1416
deallocates the (de)compression state. Note that once file is closed, you
1417
cannot call gzerror with file, since its structures have been deallocated.
1418
gzclose must not be called more than once on the same file, just as free
1419
must not be called more than once on the same allocation.
1421
gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1422
file operation error, or Z_OK on success.
1425
ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1426
ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1428
Same as gzclose(), but gzclose_r() is only for use when reading, and
1429
gzclose_w() is only for use when writing or appending. The advantage to
1430
using these instead of gzclose() is that they avoid linking in zlib
1431
compression or decompression code that is not used when only reading or only
1432
writing respectively. If gzclose() is used, then both compression and
1433
decompression code will be included the application when linking to a static
1236
1437
ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1238
Returns the error message for the last error which occurred on the
1239
given compressed file. errnum is set to zlib error number. If an
1240
error occurred in the file system and not in the compression library,
1241
errnum is set to Z_ERRNO and the application may consult errno
1242
to get the exact error code.
1439
Returns the error message for the last error which occurred on the given
1440
compressed file. errnum is set to zlib error number. If an error occurred
1441
in the file system and not in the compression library, errnum is set to
1442
Z_ERRNO and the application may consult errno to get the exact error code.
1444
The application must not modify the returned string. Future calls to
1445
this function may invalidate the previously returned string. If file is
1446
closed, then the string previously returned by gzerror will no longer be
1449
gzerror() should be used to distinguish errors from end-of-file for those
1450
functions above that do not distinguish those cases in their return values.
1245
1453
ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1247
Clears the error and end-of-file flags for file. This is analogous to the
1248
clearerr() function in stdio. This is useful for continuing to read a gzip
1455
Clears the error and end-of-file flags for file. This is analogous to the
1456
clearerr() function in stdio. This is useful for continuing to read a gzip
1249
1457
file that is being written concurrently.
1252
1461
/* checksum functions */
1255
1464
These functions are not related to compression but are exported
1256
anyway because they might be useful in applications using the
1257
compression library.
1465
anyway because they might be useful in applications using the compression
1260
1469
ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1262
1471
Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1263
return the updated checksum. If buf is NULL, this function returns
1264
the required initial value for the checksum.
1265
An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1266
much faster. Usage example:
1472
return the updated checksum. If buf is Z_NULL, this function returns the
1473
required initial value for the checksum.
1475
An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1268
1480
uLong adler = adler32(0L, Z_NULL, 0);
1339
1554
inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
1340
1555
#define inflateBackInit(strm, windowBits, window) \
1341
1556
inflateBackInit_((strm), (windowBits), (window), \
1342
ZLIB_VERSION, sizeof(z_stream))
1557
ZLIB_VERSION, sizeof(z_stream))
1559
/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1560
* change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1561
* both are true, the application gets the *64 functions, and the regular
1562
* functions are changed to 64 bits) -- in case these are set on systems
1563
* without large file support, _LFS64_LARGEFILE must also be true
1565
#if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
1566
ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1567
ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1568
ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1569
ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1570
ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1571
ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1574
#if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0
1575
# define gzopen gzopen64
1576
# define gzseek gzseek64
1577
# define gztell gztell64
1578
# define gzoffset gzoffset64
1579
# define adler32_combine adler32_combine64
1580
# define crc32_combine crc32_combine64
1581
# ifdef _LARGEFILE64_SOURCE
1582
ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1583
ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1584
ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1585
ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1586
ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1587
ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1590
ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1591
ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1592
ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1593
ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1594
ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1595
ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1598
/* hack for buggy compilers */
1345
1599
#if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1346
struct internal_state {int dummy;}; /* hack for buggy compilers */
1600
struct internal_state {int dummy;};
1603
/* undocumented functions */
1349
1604
ZEXTERN const char * ZEXPORT zError OF((int));
1350
ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
1605
ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1351
1606
ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
1607
ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1353
1609
#ifdef __cplusplus
added
removed
mozilla/security/nss/lib/zlib/zlib.h
