1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.2.13, October 13th, 2022
4 Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler
6 This software is provided 'as-is', without any express or implied
7 warranty. In no event will the authors be held liable for any damages
8 arising from the use of this software.
10 Permission is granted to anyone to use this software for any purpose,
11 including commercial applications, and to alter it and redistribute it
12 freely, subject to the following restrictions:
14 1. The origin of this software must not be misrepresented; you must not
15 claim that you wrote the original software. If you use this software
16 in a product, an acknowledgment in the product documentation would be
17 appreciated but is not required.
18 2. Altered source versions must be plainly marked as such, and must not be
19 misrepresented as being the original software.
20 3. This notice may not be removed or altered from any source distribution.
22 Jean-loup Gailly Mark Adler
23 jloup@gzip.org madler@alumni.caltech.edu
26 The data format used by the zlib library is described by RFCs (Request for
27 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
28 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
40 #define ZLIB_VERSION "1.2.13"
41 #define ZLIB_VERNUM 0x12d0
42 #define ZLIB_VER_MAJOR 1
43 #define ZLIB_VER_MINOR 2
44 #define ZLIB_VER_REVISION 13
45 #define ZLIB_VER_SUBREVISION 0
48 The 'zlib' compression library provides in-memory compression and
49 decompression functions, including integrity checks of the uncompressed data.
50 This version of the library supports only one compression method (deflation)
51 but other algorithms will be added later and will have the same stream
54 Compression can be done in a single step if the buffers are large enough,
55 or can be done by repeated calls of the compression function. In the latter
56 case, the application must provide more input and/or consume the output
57 (providing more output space) before each call.
59 The compressed data format used by default by the in-memory functions is
60 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
61 around a deflate stream, which is itself documented in RFC 1951.
63 The library also supports reading and writing files in gzip (.gz) format
64 with an interface similar to that of stdio using the functions that start
65 with "gz". The gzip format is different from the zlib format. gzip is a
66 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
68 This library can optionally read and write gzip and raw deflate streams in
71 The zlib format was designed to be compact and fast for use in memory
72 and on communications channels. The gzip format was designed for single-
73 file compression on file systems, has a larger header than zlib to maintain
74 directory information, and uses a different, slower check method than zlib.
76 The library does not install any signal handler. The decoder checks
77 the consistency of the compressed data, so the library should never crash
78 even in the case of corrupted input.
81 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
82 typedef void (*free_func) OF((voidpf opaque, voidpf address));
84 struct internal_state;
86 typedef struct z_stream_s {
87 z_const Bytef *next_in; /* next input byte */
88 uInt avail_in; /* number of bytes available at next_in */
89 uLong total_in; /* total number of input bytes read so far */
91 Bytef *next_out; /* next output byte will go here */
92 uInt avail_out; /* remaining free space at next_out */
93 uLong total_out; /* total number of bytes output so far */
95 z_const char *msg; /* last error message, NULL if no error */
96 struct internal_state FAR *state; /* not visible by applications */
98 alloc_func zalloc; /* used to allocate the internal state */
99 free_func zfree; /* used to free the internal state */
100 voidpf opaque; /* private data object passed to zalloc and zfree */
102 int data_type; /* best guess about the data type: binary or text
103 for deflate, or the decoding state for inflate */
104 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */
105 uLong reserved; /* reserved for future use */
108 typedef z_stream FAR *z_streamp;
111 gzip header information passed to and from zlib routines. See RFC 1952
112 for more details on the meanings of these fields.
114 typedef struct gz_header_s {
115 int text; /* true if compressed data believed to be text */
116 uLong time; /* modification time */
117 int xflags; /* extra flags (not used when writing a gzip file) */
118 int os; /* operating system */
119 Bytef *extra; /* pointer to extra field or Z_NULL if none */
120 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
121 uInt extra_max; /* space at extra (only when reading header) */
122 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
123 uInt name_max; /* space at name (only when reading header) */
124 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
125 uInt comm_max; /* space at comment (only when reading header) */
126 int hcrc; /* true if there was or will be a header crc */
127 int done; /* true when done reading gzip header (not used
128 when writing a gzip file) */
131 typedef gz_header FAR *gz_headerp;
134 The application must update next_in and avail_in when avail_in has dropped
135 to zero. It must update next_out and avail_out when avail_out has dropped
136 to zero. The application must initialize zalloc, zfree and opaque before
137 calling the init function. All other fields are set by the compression
138 library and must not be updated by the application.
140 The opaque value provided by the application will be passed as the first
141 parameter for calls of zalloc and zfree. This can be useful for custom
142 memory management. The compression library attaches no meaning to the
145 zalloc must return Z_NULL if there is not enough memory for the object.
146 If zlib is used in a multi-threaded application, zalloc and zfree must be
147 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
148 Z_NULL on entry to the initialization function, they are set to internal
149 routines that use the standard library functions malloc() and free().
151 On 16-bit systems, the functions zalloc and zfree must be able to allocate
152 exactly 65536 bytes, but will not be required to allocate more than this if
153 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
154 returned by zalloc for objects of exactly 65536 bytes *must* have their
155 offset normalized to zero. The default allocation function provided by this
156 library ensures this (see zutil.c). To reduce memory requirements and avoid
157 any allocation of 64K objects, at the expense of compression ratio, compile
158 the library with -DMAX_WBITS=14 (see zconf.h).
160 The fields total_in and total_out can be used for statistics or progress
161 reports. After compression, total_in holds the total size of the
162 uncompressed data and may be saved for use by the decompressor (particularly
163 if the decompressor wants to decompress everything in a single step).
169 #define Z_PARTIAL_FLUSH 1
170 #define Z_SYNC_FLUSH 2
171 #define Z_FULL_FLUSH 3
175 /* Allowed flush values; see deflate() and inflate() below for details */
178 #define Z_STREAM_END 1
179 #define Z_NEED_DICT 2
181 #define Z_STREAM_ERROR (-2)
182 #define Z_DATA_ERROR (-3)
183 #define Z_MEM_ERROR (-4)
184 #define Z_BUF_ERROR (-5)
185 #define Z_VERSION_ERROR (-6)
186 /* Return codes for the compression/decompression functions. Negative values
187 * are errors, positive values are used for special but normal events.
190 #define Z_NO_COMPRESSION 0
191 #define Z_BEST_SPEED 1
192 #define Z_BEST_COMPRESSION 9
193 #define Z_DEFAULT_COMPRESSION (-1)
194 /* compression levels */
197 #define Z_HUFFMAN_ONLY 2
200 #define Z_DEFAULT_STRATEGY 0
201 /* compression strategy; see deflateInit2() below for details */
205 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
207 /* Possible values of the data_type field for deflate() */
210 /* The deflate compression method (the only one supported in this version) */
212 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
216 #define zlib_version zlibVersion()
217 /* for compatibility with versions < 1.0.2 */
220 /* basic functions */
222 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
223 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
224 If the first character differs, the library code actually used is not
225 compatible with the zlib.h header file used by the application. This check
226 is automatically made by deflateInit and inflateInit.
230 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
232 Initializes the internal stream state for compression. The fields
233 zalloc, zfree and opaque must be initialized before by the caller. If
234 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
235 allocation functions.
237 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
238 1 gives best speed, 9 gives best compression, 0 gives no compression at all
239 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
240 requests a default compromise between speed and compression (currently
241 equivalent to level 6).
243 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
244 memory, Z_STREAM_ERROR if level is not a valid compression level, or
245 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
246 with the version assumed by the caller (ZLIB_VERSION). msg is set to null
247 if there is no error message. deflateInit does not perform any compression:
248 this will be done by deflate().
252 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
254 deflate compresses as much data as possible, and stops when the input
255 buffer becomes empty or the output buffer becomes full. It may introduce
256 some output latency (reading input without producing any output) except when
259 The detailed semantics are as follows. deflate performs one or both of the
262 - Compress more input starting at next_in and update next_in and avail_in
263 accordingly. If not all input can be processed (because there is not
264 enough room in the output buffer), next_in and avail_in are updated and
265 processing will resume at this point for the next call of deflate().
267 - Generate more output starting at next_out and update next_out and avail_out
268 accordingly. This action is forced if the parameter flush is non zero.
269 Forcing flush frequently degrades the compression ratio, so this parameter
270 should be set only when necessary. Some output may be provided even if
273 Before the call of deflate(), the application should ensure that at least
274 one of the actions is possible, by providing more input and/or consuming more
275 output, and updating avail_in or avail_out accordingly; avail_out should
276 never be zero before the call. The application can consume the compressed
277 output when it wants, for example when the output buffer is full (avail_out
278 == 0), or after each call of deflate(). If deflate returns Z_OK and with
279 zero avail_out, it must be called again after making room in the output
280 buffer because there might be more output pending. See deflatePending(),
281 which can be used if desired to determine whether or not there is more output
284 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
285 decide how much data to accumulate before producing output, in order to
286 maximize compression.
288 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
289 flushed to the output buffer and the output is aligned on a byte boundary, so
290 that the decompressor can get all input data available so far. (In
291 particular avail_in is zero after the call if enough output space has been
292 provided before the call.) Flushing may degrade compression for some
293 compression algorithms and so it should be used only when necessary. This
294 completes the current deflate block and follows it with an empty stored block
295 that is three bits plus filler bits to the next byte, followed by four bytes
298 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
299 output buffer, but the output is not aligned to a byte boundary. All of the
300 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
301 This completes the current deflate block and follows it with an empty fixed
302 codes block that is 10 bits long. This assures that enough bytes are output
303 in order for the decompressor to finish the block before the empty fixed
306 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
307 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
308 seven bits of the current block are held to be written as the next byte after
309 the next deflate block is completed. In this case, the decompressor may not
310 be provided enough bits at this point in order to complete decompression of
311 the data provided so far to the compressor. It may need to wait for the next
312 block to be emitted. This is for advanced applications that need to control
313 the emission of deflate blocks.
315 If flush is set to Z_FULL_FLUSH, all output is flushed as with
316 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
317 restart from this point if previous compressed data has been damaged or if
318 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
321 If deflate returns with avail_out == 0, this function must be called again
322 with the same value of the flush parameter and more output space (updated
323 avail_out), until the flush is complete (deflate returns with non-zero
324 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
325 avail_out is greater than six to avoid repeated flush markers due to
326 avail_out == 0 on return.
328 If the parameter flush is set to Z_FINISH, pending input is processed,
329 pending output is flushed and deflate returns with Z_STREAM_END if there was
330 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this
331 function must be called again with Z_FINISH and more output space (updated
332 avail_out) but no more input data, until it returns with Z_STREAM_END or an
333 error. After deflate has returned Z_STREAM_END, the only possible operations
334 on the stream are deflateReset or deflateEnd.
336 Z_FINISH can be used in the first deflate call after deflateInit if all the
337 compression is to be done in a single step. In order to complete in one
338 call, avail_out must be at least the value returned by deflateBound (see
339 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough
340 output space is provided, deflate will not return Z_STREAM_END, and it must
341 be called again as described above.
343 deflate() sets strm->adler to the Adler-32 checksum of all input read
344 so far (that is, total_in bytes). If a gzip stream is being generated, then
345 strm->adler will be the CRC-32 checksum of the input read so far. (See
348 deflate() may update strm->data_type if it can make a good guess about
349 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is
350 considered binary. This field is only for information purposes and does not
351 affect the compression algorithm in any manner.
353 deflate() returns Z_OK if some progress has been made (more input
354 processed or more output produced), Z_STREAM_END if all input has been
355 consumed and all output has been produced (only when flush is set to
356 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
357 if next_in or next_out was Z_NULL or the state was inadvertently written over
358 by the application), or Z_BUF_ERROR if no progress is possible (for example
359 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
360 deflate() can be called again with more input and more output space to
361 continue compressing.
365 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
367 All dynamically allocated data structures for this stream are freed.
368 This function discards any unprocessed input and does not flush any pending
371 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
372 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
373 prematurely (some input or output was discarded). In the error case, msg
374 may be set but then points to a static string (which must not be
378 #endif /* !Z_FREETYPE */
381 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
383 Initializes the internal stream state for decompression. The fields
384 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
385 the caller. In the current version of inflate, the provided input is not
386 read or consumed. The allocation of a sliding window will be deferred to
387 the first call of inflate (if the decompression does not complete on the
388 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates
389 them to use default allocation functions.
391 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
392 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
393 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
394 invalid, such as a null pointer to the structure. msg is set to null if
395 there is no error message. inflateInit does not perform any decompression.
396 Actual decompression will be done by inflate(). So next_in, and avail_in,
397 next_out, and avail_out are unused and unchanged. The current
398 implementation of inflateInit() does not process any header information --
399 that is deferred until inflate() is called.
403 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
405 inflate decompresses as much data as possible, and stops when the input
406 buffer becomes empty or the output buffer becomes full. It may introduce
407 some output latency (reading input without producing any output) except when
410 The detailed semantics are as follows. inflate performs one or both of the
413 - Decompress more input starting at next_in and update next_in and avail_in
414 accordingly. If not all input can be processed (because there is not
415 enough room in the output buffer), then next_in and avail_in are updated
416 accordingly, and processing will resume at this point for the next call of
419 - Generate more output starting at next_out and update next_out and avail_out
420 accordingly. inflate() provides as much output as possible, until there is
421 no more input data or no more space in the output buffer (see below about
422 the flush parameter).
424 Before the call of inflate(), the application should ensure that at least
425 one of the actions is possible, by providing more input and/or consuming more
426 output, and updating the next_* and avail_* values accordingly. If the
427 caller of inflate() does not provide both available input and available
428 output space, it is possible that there will be no progress made. The
429 application can consume the uncompressed output when it wants, for example
430 when the output buffer is full (avail_out == 0), or after each call of
431 inflate(). If inflate returns Z_OK and with zero avail_out, it must be
432 called again after making room in the output buffer because there might be
435 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
436 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
437 output as possible to the output buffer. Z_BLOCK requests that inflate()
438 stop if and when it gets to the next deflate block boundary. When decoding
439 the zlib or gzip format, this will cause inflate() to return immediately
440 after the header and before the first block. When doing a raw inflate,
441 inflate() will go ahead and process the first block, and will return when it
442 gets to the end of that block, or when it runs out of data.
444 The Z_BLOCK option assists in appending to or combining deflate streams.
445 To assist in this, on return inflate() always sets strm->data_type to the
446 number of unused bits in the last byte taken from strm->next_in, plus 64 if
447 inflate() is currently decoding the last block in the deflate stream, plus
448 128 if inflate() returned immediately after decoding an end-of-block code or
449 decoding the complete header up to just before the first byte of the deflate
450 stream. The end-of-block will not be indicated until all of the uncompressed
451 data from that block has been written to strm->next_out. The number of
452 unused bits may in general be greater than seven, except when bit 7 of
453 data_type is set, in which case the number of unused bits will be less than
454 eight. data_type is set as noted here every time inflate() returns for all
455 flush options, and so can be used to determine the amount of currently
456 consumed input in bits.
458 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
459 end of each deflate block header is reached, before any actual data in that
460 block is decoded. This allows the caller to determine the length of the
461 deflate block header for later use in random access within a deflate block.
462 256 is added to the value of strm->data_type when inflate() returns
463 immediately after reaching the end of the deflate block header.
465 inflate() should normally be called until it returns Z_STREAM_END or an
466 error. However if all decompression is to be performed in a single step (a
467 single call of inflate), the parameter flush should be set to Z_FINISH. In
468 this case all pending input is processed and all pending output is flushed;
469 avail_out must be large enough to hold all of the uncompressed data for the
470 operation to complete. (The size of the uncompressed data may have been
471 saved by the compressor for this purpose.) The use of Z_FINISH is not
472 required to perform an inflation in one step. However it may be used to
473 inform inflate that a faster approach can be used for the single inflate()
474 call. Z_FINISH also informs inflate to not maintain a sliding window if the
475 stream completes, which reduces inflate's memory footprint. If the stream
476 does not complete, either because not all of the stream is provided or not
477 enough output space is provided, then a sliding window will be allocated and
478 inflate() can be called again to continue the operation as if Z_NO_FLUSH had
481 In this implementation, inflate() always flushes as much output as
482 possible to the output buffer, and always uses the faster approach on the
483 first call. So the effects of the flush parameter in this implementation are
484 on the return value of inflate() as noted below, when inflate() returns early
485 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
486 memory for a sliding window when Z_FINISH is used.
488 If a preset dictionary is needed after this call (see inflateSetDictionary
489 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
490 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
491 strm->adler to the Adler-32 checksum of all output produced so far (that is,
492 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
493 below. At the end of the stream, inflate() checks that its computed Adler-32
494 checksum is equal to that saved by the compressor and returns Z_STREAM_END
495 only if the checksum is correct.
497 inflate() can decompress and check either zlib-wrapped or gzip-wrapped
498 deflate data. The header type is detected automatically, if requested when
499 initializing with inflateInit2(). Any information contained in the gzip
500 header is not retained unless inflateGetHeader() is used. When processing
501 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
502 produced so far. The CRC-32 is checked against the gzip trailer, as is the
503 uncompressed length, modulo 2^32.
505 inflate() returns Z_OK if some progress has been made (more input processed
506 or more output produced), Z_STREAM_END if the end of the compressed data has
507 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
508 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
509 corrupted (input stream not conforming to the zlib format or incorrect check
510 value, in which case strm->msg points to a string with a more specific
511 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
512 next_in or next_out was Z_NULL, or the state was inadvertently written over
513 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
514 if no progress was possible or if there was not enough room in the output
515 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
516 inflate() can be called again with more input and more output space to
517 continue decompressing. If Z_DATA_ERROR is returned, the application may
518 then call inflateSync() to look for a good compression block if a partial
519 recovery of the data is to be attempted.
523 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
525 All dynamically allocated data structures for this stream are freed.
526 This function discards any unprocessed input and does not flush any pending
529 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
534 /* Advanced functions */
537 The following functions are needed only in some special applications.
543 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
550 This is another version of deflateInit with more compression options. The
551 fields zalloc, zfree and opaque must be initialized before by the caller.
553 The method parameter is the compression method. It must be Z_DEFLATED in
554 this version of the library.
556 The windowBits parameter is the base two logarithm of the window size
557 (the size of the history buffer). It should be in the range 8..15 for this
558 version of the library. Larger values of this parameter result in better
559 compression at the expense of memory usage. The default value is 15 if
560 deflateInit is used instead.
562 For the current implementation of deflate(), a windowBits value of 8 (a
563 window size of 256 bytes) is not supported. As a result, a request for 8
564 will result in 9 (a 512-byte window). In that case, providing 8 to
565 inflateInit2() will result in an error when the zlib header with 9 is
566 checked against the initialization of inflate(). The remedy is to not use 8
567 with deflateInit2() with this initialization, or at least in that case use 9
570 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
571 determines the window size. deflate() will then generate raw deflate data
572 with no zlib header or trailer, and will not compute a check value.
574 windowBits can also be greater than 15 for optional gzip encoding. Add
575 16 to windowBits to write a simple gzip header and trailer around the
576 compressed data instead of a zlib wrapper. The gzip header will have no
577 file name, no extra data, no comment, no modification time (set to zero), no
578 header crc, and the operating system will be set to the appropriate value,
579 if the operating system was determined at compile time. If a gzip stream is
580 being written, strm->adler is a CRC-32 instead of an Adler-32.
582 For raw deflate or gzip encoding, a request for a 256-byte window is
583 rejected as invalid, since only the zlib header provides a means of
584 transmitting the window size to the decompressor.
586 The memLevel parameter specifies how much memory should be allocated
587 for the internal compression state. memLevel=1 uses minimum memory but is
588 slow and reduces compression ratio; memLevel=9 uses maximum memory for
589 optimal speed. The default value is 8. See zconf.h for total memory usage
590 as a function of windowBits and memLevel.
592 The strategy parameter is used to tune the compression algorithm. Use the
593 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
594 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
595 string match), or Z_RLE to limit match distances to one (run-length
596 encoding). Filtered data consists mostly of small values with a somewhat
597 random distribution. In this case, the compression algorithm is tuned to
598 compress them better. The effect of Z_FILTERED is to force more Huffman
599 coding and less string matching; it is somewhat intermediate between
600 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
601 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
602 strategy parameter only affects the compression ratio but not the
603 correctness of the compressed output even if it is not set appropriately.
604 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
605 decoder for special applications.
607 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
608 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
609 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
610 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
611 set to null if there is no error message. deflateInit2 does not perform any
612 compression: this will be done by deflate().
615 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
616 const Bytef *dictionary,
619 Initializes the compression dictionary from the given byte sequence
620 without producing any compressed output. When using the zlib format, this
621 function must be called immediately after deflateInit, deflateInit2 or
622 deflateReset, and before any call of deflate. When doing raw deflate, this
623 function must be called either before any call of deflate, or immediately
624 after the completion of a deflate block, i.e. after all input has been
625 consumed and all output has been delivered when using any of the flush
626 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
627 compressor and decompressor must use exactly the same dictionary (see
628 inflateSetDictionary).
630 The dictionary should consist of strings (byte sequences) that are likely
631 to be encountered later in the data to be compressed, with the most commonly
632 used strings preferably put towards the end of the dictionary. Using a
633 dictionary is most useful when the data to be compressed is short and can be
634 predicted with good accuracy; the data can then be compressed better than
635 with the default empty dictionary.
637 Depending on the size of the compression data structures selected by
638 deflateInit or deflateInit2, a part of the dictionary may in effect be
639 discarded, for example if the dictionary is larger than the window size
640 provided in deflateInit or deflateInit2. Thus the strings most likely to be
641 useful should be put at the end of the dictionary, not at the front. In
642 addition, the current implementation of deflate will use at most the window
643 size minus 262 bytes of the provided dictionary.
645 Upon return of this function, strm->adler is set to the Adler-32 value
646 of the dictionary; the decompressor may later use this value to determine
647 which dictionary has been used by the compressor. (The Adler-32 value
648 applies to the whole dictionary even if only a subset of the dictionary is
649 actually used by the compressor.) If a raw deflate was requested, then the
650 Adler-32 value is not computed and strm->adler is not set.
652 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
653 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
654 inconsistent (for example if deflate has already been called for this stream
655 or if not at a block boundary for raw deflate). deflateSetDictionary does
656 not perform any compression: this will be done by deflate().
659 ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm,
663 Returns the sliding dictionary being maintained by deflate. dictLength is
664 set to the number of bytes in the dictionary, and that many bytes are copied
665 to dictionary. dictionary must have enough space, where 32768 bytes is
666 always enough. If deflateGetDictionary() is called with dictionary equal to
667 Z_NULL, then only the dictionary length is returned, and nothing is copied.
668 Similarly, if dictLength is Z_NULL, then it is not set.
670 deflateGetDictionary() may return a length less than the window size, even
671 when more than the window size in input has been provided. It may return up
672 to 258 bytes less in that case, due to how zlib's implementation of deflate
673 manages the sliding window and lookahead for matches, where matches can be
674 up to 258 bytes long. If the application needs the last window-size bytes of
675 input, then that would need to be saved by the application outside of zlib.
677 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
678 stream state is inconsistent.
681 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
684 Sets the destination stream as a complete copy of the source stream.
686 This function can be useful when several compression strategies will be
687 tried, for example when there are several ways of pre-processing the input
688 data with a filter. The streams that will be discarded should then be freed
689 by calling deflateEnd. Note that deflateCopy duplicates the internal
690 compression state which can be quite large, so this strategy is slow and can
691 consume lots of memory.
693 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
694 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
695 (such as zalloc being Z_NULL). msg is left unchanged in both source and
699 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
701 This function is equivalent to deflateEnd followed by deflateInit, but
702 does not free and reallocate the internal compression state. The stream
703 will leave the compression level and any other attributes that may have been
706 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
707 stream state was inconsistent (such as zalloc or state being Z_NULL).
710 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
714 Dynamically update the compression level and compression strategy. The
715 interpretation of level and strategy is as in deflateInit2(). This can be
716 used to switch between compression and straight copy of the input data, or
717 to switch to a different kind of input data requiring a different strategy.
718 If the compression approach (which is a function of the level) or the
719 strategy is changed, and if there have been any deflate() calls since the
720 state was initialized or reset, then the input available so far is
721 compressed with the old level and strategy using deflate(strm, Z_BLOCK).
722 There are three approaches for the compression levels 0, 1..3, and 4..9
723 respectively. The new level and strategy will take effect at the next call
726 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
727 not have enough output space to complete, then the parameter change will not
728 take effect. In this case, deflateParams() can be called again with the
729 same parameters and more output space to try again.
731 In order to assure a change in the parameters on the first try, the
732 deflate stream should be flushed using deflate() with Z_BLOCK or other flush
733 request until strm.avail_out is not zero, before calling deflateParams().
734 Then no more input data should be provided before the deflateParams() call.
735 If this is done, the old level and strategy will be applied to the data
736 compressed before deflateParams(), and the new level and strategy will be
737 applied to the the data compressed after deflateParams().
739 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
740 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
741 there was not enough output space to complete the compression of the
742 available input data before a change in the strategy or approach. Note that
743 in the case of a Z_BUF_ERROR, the parameters are not changed. A return
744 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
745 retried with more output space.
748 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
754 Fine tune deflate's internal compression parameters. This should only be
755 used by someone who understands the algorithm used by zlib's deflate for
756 searching for the best matching string, and even then only by the most
757 fanatic optimizer trying to squeeze out the last compressed bit for their
758 specific input data. Read the deflate.c source code for the meaning of the
759 max_lazy, good_length, nice_length, and max_chain parameters.
761 deflateTune() can be called after deflateInit() or deflateInit2(), and
762 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
765 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
768 deflateBound() returns an upper bound on the compressed size after
769 deflation of sourceLen bytes. It must be called after deflateInit() or
770 deflateInit2(), and after deflateSetHeader(), if used. This would be used
771 to allocate an output buffer for deflation in a single pass, and so would be
772 called before deflate(). If that first deflate() call is provided the
773 sourceLen input bytes, an output buffer allocated to the size returned by
774 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
775 to return Z_STREAM_END. Note that it is possible for the compressed size to
776 be larger than the value returned by deflateBound() if flush options other
777 than Z_FINISH or Z_NO_FLUSH are used.
780 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
784 deflatePending() returns the number of bytes and bits of output that have
785 been generated, but not yet provided in the available output. The bytes not
786 provided would be due to the available output space having being consumed.
787 The number of bits of output not provided are between 0 and 7, where they
788 await more bits to join them in order to fill out a full byte. If pending
789 or bits are Z_NULL, then those values are not set.
791 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
792 stream state was inconsistent.
795 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
799 deflatePrime() inserts bits in the deflate output stream. The intent
800 is that this function is used to start off the deflate output with the bits
801 leftover from a previous deflate stream when appending to it. As such, this
802 function can only be used for raw deflate, and must be used before the first
803 deflate() call after a deflateInit2() or deflateReset(). bits must be less
804 than or equal to 16, and that many of the least significant bits of value
805 will be inserted in the output.
807 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
808 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
809 source stream state was inconsistent.
812 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
815 deflateSetHeader() provides gzip header information for when a gzip
816 stream is requested by deflateInit2(). deflateSetHeader() may be called
817 after deflateInit2() or deflateReset() and before the first call of
818 deflate(). The text, time, os, extra field, name, and comment information
819 in the provided gz_header structure are written to the gzip header (xflag is
820 ignored -- the extra flags are set according to the compression level). The
821 caller must assure that, if not Z_NULL, name and comment are terminated with
822 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
823 available there. If hcrc is true, a gzip header crc is included. Note that
824 the current versions of the command-line version of gzip (up through version
825 1.3.x) do not support header crc's, and will report that it is a "multi-part
826 gzip file" and give up.
828 If deflateSetHeader is not used, the default gzip header has text false,
829 the time set to zero, and os set to 255, with no extra, name, or comment
830 fields. The gzip header is returned to the default state by deflateReset().
832 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
833 stream state was inconsistent.
837 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
840 This is another version of inflateInit with an extra parameter. The
841 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
842 before by the caller.
844 The windowBits parameter is the base two logarithm of the maximum window
845 size (the size of the history buffer). It should be in the range 8..15 for
846 this version of the library. The default value is 15 if inflateInit is used
847 instead. windowBits must be greater than or equal to the windowBits value
848 provided to deflateInit2() while compressing, or it must be equal to 15 if
849 deflateInit2() was not used. If a compressed stream with a larger window
850 size is given as input, inflate() will return with the error code
851 Z_DATA_ERROR instead of trying to allocate a larger window.
853 windowBits can also be zero to request that inflate use the window size in
854 the zlib header of the compressed stream.
856 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
857 determines the window size. inflate() will then process raw deflate data,
858 not looking for a zlib or gzip header, not generating a check value, and not
859 looking for any check values for comparison at the end of the stream. This
860 is for use with other formats that use the deflate compressed data format
861 such as zip. Those formats provide their own check values. If a custom
862 format is developed using the raw deflate format for compressed data, it is
863 recommended that a check value such as an Adler-32 or a CRC-32 be applied to
864 the uncompressed data as is done in the zlib, gzip, and zip formats. For
865 most applications, the zlib format should be used as is. Note that comments
866 above on the use in deflateInit2() applies to the magnitude of windowBits.
868 windowBits can also be greater than 15 for optional gzip decoding. Add
869 32 to windowBits to enable zlib and gzip decoding with automatic header
870 detection, or add 16 to decode only the gzip format (the zlib format will
871 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
872 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see
873 below), inflate() will *not* automatically decode concatenated gzip members.
874 inflate() will return Z_STREAM_END at the end of the gzip member. The state
875 would need to be reset to continue decoding a subsequent gzip member. This
876 *must* be done if there is more data after a gzip member, in order for the
877 decompression to be compliant with the gzip standard (RFC 1952).
879 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
880 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
881 version assumed by the caller, or Z_STREAM_ERROR if the parameters are
882 invalid, such as a null pointer to the structure. msg is set to null if
883 there is no error message. inflateInit2 does not perform any decompression
884 apart from possibly reading the zlib header if present: actual decompression
885 will be done by inflate(). (So next_in and avail_in may be modified, but
886 next_out and avail_out are unused and unchanged.) The current implementation
887 of inflateInit2() does not process any header information -- that is
888 deferred until inflate() is called.
891 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
892 const Bytef *dictionary,
895 Initializes the decompression dictionary from the given uncompressed byte
896 sequence. This function must be called immediately after a call of inflate,
897 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
898 can be determined from the Adler-32 value returned by that call of inflate.
899 The compressor and decompressor must use exactly the same dictionary (see
900 deflateSetDictionary). For raw inflate, this function can be called at any
901 time to set the dictionary. If the provided dictionary is smaller than the
902 window and there is already data in the window, then the provided dictionary
903 will amend what's there. The application must insure that the dictionary
904 that was used for compression is provided.
906 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
907 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
908 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
909 expected one (incorrect Adler-32 value). inflateSetDictionary does not
910 perform any decompression: this will be done by subsequent calls of
914 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
918 Returns the sliding dictionary being maintained by inflate. dictLength is
919 set to the number of bytes in the dictionary, and that many bytes are copied
920 to dictionary. dictionary must have enough space, where 32768 bytes is
921 always enough. If inflateGetDictionary() is called with dictionary equal to
922 Z_NULL, then only the dictionary length is returned, and nothing is copied.
923 Similarly, if dictLength is Z_NULL, then it is not set.
925 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
926 stream state is inconsistent.
929 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
931 Skips invalid compressed data until a possible full flush point (see above
932 for the description of deflate with Z_FULL_FLUSH) can be found, or until all
933 available input is skipped. No output is provided.
935 inflateSync searches for a 00 00 FF FF pattern in the compressed data.
936 All full flush points have this pattern, but not all occurrences of this
937 pattern are full flush points.
939 inflateSync returns Z_OK if a possible full flush point has been found,
940 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
941 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
942 In the success case, the application may save the current current value of
943 total_in which indicates where valid compressed data was found. In the
944 error case, the application may repeatedly call inflateSync, providing more
945 input each time, until success or end of the input data.
948 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
951 Sets the destination stream as a complete copy of the source stream.
953 This function can be useful when randomly accessing a large stream. The
954 first pass through the stream can periodically record the inflate state,
955 allowing restarting inflate at those points when randomly accessing the
958 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
959 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
960 (such as zalloc being Z_NULL). msg is left unchanged in both source and
964 #endif /* !Z_FREETYPE */
966 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
968 This function is equivalent to inflateEnd followed by inflateInit,
969 but does not free and reallocate the internal decompression state. The
970 stream will keep attributes that may have been set by inflateInit2.
972 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
973 stream state was inconsistent (such as zalloc or state being Z_NULL).
976 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
979 This function is the same as inflateReset, but it also permits changing
980 the wrap and window size requests. The windowBits parameter is interpreted
981 the same as it is for inflateInit2. If the window size is changed, then the
982 memory allocated for the window is freed, and the window will be reallocated
983 by inflate() if needed.
985 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
986 stream state was inconsistent (such as zalloc or state being Z_NULL), or if
987 the windowBits parameter is invalid.
992 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
996 This function inserts bits in the inflate input stream. The intent is
997 that this function is used to start inflating at a bit position in the
998 middle of a byte. The provided bits will be used before any bytes are used
999 from next_in. This function should only be used with raw inflate, and
1000 should be used before the first inflate() call after inflateInit2() or
1001 inflateReset(). bits must be less than or equal to 16, and that many of the
1002 least significant bits of value will be inserted in the input.
1004 If bits is negative, then the input stream bit buffer is emptied. Then
1005 inflatePrime() can be called again to put bits in the buffer. This is used
1006 to clear out bits leftover after feeding inflate a block description prior
1007 to feeding inflate codes.
1009 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
1010 stream state was inconsistent.
1013 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
1015 This function returns two values, one in the lower 16 bits of the return
1016 value, and the other in the remaining upper bits, obtained by shifting the
1017 return value down 16 bits. If the upper value is -1 and the lower value is
1018 zero, then inflate() is currently decoding information outside of a block.
1019 If the upper value is -1 and the lower value is non-zero, then inflate is in
1020 the middle of a stored block, with the lower value equaling the number of
1021 bytes from the input remaining to copy. If the upper value is not -1, then
1022 it is the number of bits back from the current bit position in the input of
1023 the code (literal or length/distance pair) currently being processed. In
1024 that case the lower value is the number of bytes already emitted for that
1027 A code is being processed if inflate is waiting for more input to complete
1028 decoding of the code, or if it has completed decoding but is waiting for
1029 more output space to write the literal or match data.
1031 inflateMark() is used to mark locations in the input data for random
1032 access, which may be at bit positions, and to note those cases where the
1033 output of a code may span boundaries of random access blocks. The current
1034 location in the input stream can be determined from avail_in and data_type
1035 as noted in the description for the Z_BLOCK flush parameter for inflate.
1037 inflateMark returns the value noted above, or -65536 if the provided
1038 source stream state was inconsistent.
1041 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
1044 inflateGetHeader() requests that gzip header information be stored in the
1045 provided gz_header structure. inflateGetHeader() may be called after
1046 inflateInit2() or inflateReset(), and before the first call of inflate().
1047 As inflate() processes the gzip stream, head->done is zero until the header
1048 is completed, at which time head->done is set to one. If a zlib stream is
1049 being decoded, then head->done is set to -1 to indicate that there will be
1050 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
1051 used to force inflate() to return immediately after header processing is
1052 complete and before any actual data is decompressed.
1054 The text, time, xflags, and os fields are filled in with the gzip header
1055 contents. hcrc is set to true if there is a header CRC. (The header CRC
1056 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
1057 contains the maximum number of bytes to write to extra. Once done is true,
1058 extra_len contains the actual extra field length, and extra contains the
1059 extra field, or that field truncated if extra_max is less than extra_len.
1060 If name is not Z_NULL, then up to name_max characters are written there,
1061 terminated with a zero unless the length is greater than name_max. If
1062 comment is not Z_NULL, then up to comm_max characters are written there,
1063 terminated with a zero unless the length is greater than comm_max. When any
1064 of extra, name, or comment are not Z_NULL and the respective field is not
1065 present in the header, then that field is set to Z_NULL to signal its
1066 absence. This allows the use of deflateSetHeader() with the returned
1067 structure to duplicate the header. However if those fields are set to
1068 allocated memory, then the application will need to save those pointers
1069 elsewhere so that they can be eventually freed.
1071 If inflateGetHeader is not used, then the header information is simply
1072 discarded. The header is always checked for validity, including the header
1073 CRC if present. inflateReset() will reset the process to discard the header
1074 information. The application would need to call inflateGetHeader() again to
1075 retrieve the header from the next gzip stream.
1077 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1078 stream state was inconsistent.
1081 #endif /* !Z_FREETYPE */
1084 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1085 unsigned char FAR *window));
1087 Initialize the internal stream state for decompression using inflateBack()
1088 calls. The fields zalloc, zfree and opaque in strm must be initialized
1089 before the call. If zalloc and zfree are Z_NULL, then the default library-
1090 derived memory allocation routines are used. windowBits is the base two
1091 logarithm of the window size, in the range 8..15. window is a caller
1092 supplied buffer of that size. Except for special applications where it is
1093 assured that deflate was used with small window sizes, windowBits must be 15
1094 and a 32K byte window must be supplied to be able to decompress general
1097 See inflateBack() for the usage of these routines.
1099 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1100 the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1101 allocated, or Z_VERSION_ERROR if the version of the library does not match
1102 the version of the header file.
1105 typedef unsigned (*in_func) OF((void FAR *,
1106 z_const unsigned char FAR * FAR *));
1107 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1111 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1112 in_func in, void FAR *in_desc,
1113 out_func out, void FAR *out_desc));
1115 inflateBack() does a raw inflate with a single call using a call-back
1116 interface for input and output. This is potentially more efficient than
1117 inflate() for file i/o applications, in that it avoids copying between the
1118 output and the sliding window by simply making the window itself the output
1119 buffer. inflate() can be faster on modern CPUs when used with large
1120 buffers. inflateBack() trusts the application to not change the output
1121 buffer passed by the output function, at least until inflateBack() returns.
1123 inflateBackInit() must be called first to allocate the internal state
1124 and to initialize the state with the user-provided window buffer.
1125 inflateBack() may then be used multiple times to inflate a complete, raw
1126 deflate stream with each call. inflateBackEnd() is then called to free the
1129 A raw deflate stream is one with no zlib or gzip header or trailer.
1130 This routine would normally be used in a utility that reads zip or gzip
1131 files and writes out uncompressed files. The utility would decode the
1132 header and process the trailer on its own, hence this routine expects only
1133 the raw deflate stream to decompress. This is different from the default
1134 behavior of inflate(), which expects a zlib header and trailer around the
1137 inflateBack() uses two subroutines supplied by the caller that are then
1138 called by inflateBack() for input and output. inflateBack() calls those
1139 routines until it reads a complete deflate stream and writes out all of the
1140 uncompressed data, or until it encounters an error. The function's
1141 parameters and return types are defined above in the in_func and out_func
1142 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1143 number of bytes of provided input, and a pointer to that input in buf. If
1144 there is no input available, in() must return zero -- buf is ignored in that
1145 case -- and inflateBack() will return a buffer error. inflateBack() will
1146 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
1147 out() should return zero on success, or non-zero on failure. If out()
1148 returns non-zero, inflateBack() will return with an error. Neither in() nor
1149 out() are permitted to change the contents of the window provided to
1150 inflateBackInit(), which is also the buffer that out() uses to write from.
1151 The length written by out() will be at most the window size. Any non-zero
1152 amount of input may be provided by in().
1154 For convenience, inflateBack() can be provided input on the first call by
1155 setting strm->next_in and strm->avail_in. If that input is exhausted, then
1156 in() will be called. Therefore strm->next_in must be initialized before
1157 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1158 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1159 must also be initialized, and then if strm->avail_in is not zero, input will
1160 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1162 The in_desc and out_desc parameters of inflateBack() is passed as the
1163 first parameter of in() and out() respectively when they are called. These
1164 descriptors can be optionally used to pass any information that the caller-
1165 supplied in() and out() functions need to do their job.
1167 On return, inflateBack() will set strm->next_in and strm->avail_in to
1168 pass back any unused input that was provided by the last in() call. The
1169 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1170 if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1171 in the deflate stream (in which case strm->msg is set to indicate the nature
1172 of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1173 In the case of Z_BUF_ERROR, an input or output error can be distinguished
1174 using strm->next_in which will be Z_NULL only if in() returned an error. If
1175 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1176 non-zero. (in() will always be called before out(), so strm->next_in is
1177 assured to be defined if out() returns non-zero.) Note that inflateBack()
1181 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1183 All memory allocated by inflateBackInit() is freed.
1185 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1186 state was inconsistent.
1189 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1190 /* Return flags indicating compile-time options.
1192 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1195 5.4: size of voidpf (pointer)
1196 7.6: size of z_off_t
1198 Compiler, assembler, and debug options:
1200 9: ASMV or ASMINF -- use ASM code
1201 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1204 One-time table building (smaller code, but not thread-safe if true):
1205 12: BUILDFIXED -- build static block decoding tables when needed
1206 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1209 Library content (indicates missing functionality):
1210 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1211 deflate code when not needed)
1212 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1213 and decode gzip streams (to avoid linking crc code)
1216 Operation variations (changes in library functionality):
1217 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1218 21: FASTEST -- deflate algorithm with only one, lowest compression level
1221 The sprintf variant used by gzprintf (zero is best):
1222 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1223 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1224 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1230 #endif /* !Z_FREETYPE */
1234 /* utility functions */
1237 The following utility functions are implemented on top of the basic
1238 stream-oriented functions. To simplify the interface, some default options
1239 are assumed (compression level and memory usage, standard memory allocation
1240 functions). The source code of these utility functions can be modified if
1241 you need special options.
1244 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
1245 const Bytef *source, uLong sourceLen));
1247 Compresses the source buffer into the destination buffer. sourceLen is
1248 the byte length of the source buffer. Upon entry, destLen is the total size
1249 of the destination buffer, which must be at least the value returned by
1250 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1251 compressed data. compress() is equivalent to compress2() with a level
1252 parameter of Z_DEFAULT_COMPRESSION.
1254 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1255 enough memory, Z_BUF_ERROR if there was not enough room in the output
1259 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
1260 const Bytef *source, uLong sourceLen,
1263 Compresses the source buffer into the destination buffer. The level
1264 parameter has the same meaning as in deflateInit. sourceLen is the byte
1265 length of the source buffer. Upon entry, destLen is the total size of the
1266 destination buffer, which must be at least the value returned by
1267 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1270 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1271 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1272 Z_STREAM_ERROR if the level parameter is invalid.
1275 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1277 compressBound() returns an upper bound on the compressed size after
1278 compress() or compress2() on sourceLen bytes. It would be used before a
1279 compress() or compress2() call to allocate the destination buffer.
1282 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
1283 const Bytef *source, uLong sourceLen));
1285 Decompresses the source buffer into the destination buffer. sourceLen is
1286 the byte length of the source buffer. Upon entry, destLen is the total size
1287 of the destination buffer, which must be large enough to hold the entire
1288 uncompressed data. (The size of the uncompressed data must have been saved
1289 previously by the compressor and transmitted to the decompressor by some
1290 mechanism outside the scope of this compression library.) Upon exit, destLen
1291 is the actual size of the uncompressed data.
1293 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1294 enough memory, Z_BUF_ERROR if there was not enough room in the output
1295 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1296 the case where there is not enough room, uncompress() will fill the output
1297 buffer with the uncompressed data up to that point.
1300 ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen,
1301 const Bytef *source, uLong *sourceLen));
1303 Same as uncompress, except that sourceLen is a pointer, where the
1304 length of the source is *sourceLen. On return, *sourceLen is the number of
1305 source bytes consumed.
1308 /* gzip file access functions */
1311 This library supports reading and writing files in gzip (.gz) format with
1312 an interface similar to that of stdio, using the functions that start with
1313 "gz". The gzip format is different from the zlib format. gzip is a gzip
1314 wrapper, documented in RFC 1952, wrapped around a deflate stream.
1317 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
1320 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1322 Open the gzip (.gz) file at path for reading and decompressing, or
1323 compressing and writing. The mode parameter is as in fopen ("rb" or "wb")
1324 but can also include a compression level ("wb9") or a strategy: 'f' for
1325 filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h",
1326 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression
1327 as in "wb9F". (See the description of deflateInit2 for more information
1328 about the strategy parameter.) 'T' will request transparent writing or
1329 appending with no compression and not using the gzip format.
1331 "a" can be used instead of "w" to request that the gzip stream that will
1332 be written be appended to the file. "+" will result in an error, since
1333 reading and writing to the same gzip file is not supported. The addition of
1334 "x" when writing will create the file exclusively, which fails if the file
1335 already exists. On systems that support it, the addition of "e" when
1336 reading or writing will set the flag to close the file on an execve() call.
1338 These functions, as well as gzip, will read and decode a sequence of gzip
1339 streams in a file. The append function of gzopen() can be used to create
1340 such a file. (Also see gzflush() for another way to do this.) When
1341 appending, gzopen does not test whether the file begins with a gzip stream,
1342 nor does it look for the end of the gzip streams to begin appending. gzopen
1343 will simply append a gzip stream to the existing file.
1345 gzopen can be used to read a file which is not in gzip format; in this
1346 case gzread will directly read from the file without decompression. When
1347 reading, this will be detected automatically by looking for the magic two-
1350 gzopen returns NULL if the file could not be opened, if there was
1351 insufficient memory to allocate the gzFile state, or if an invalid mode was
1352 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1353 errno can be checked to determine if the reason gzopen failed was that the
1354 file could not be opened.
1357 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1359 Associate a gzFile with the file descriptor fd. File descriptors are
1360 obtained from calls like open, dup, creat, pipe or fileno (if the file has
1361 been previously opened with fopen). The mode parameter is as in gzopen.
1363 The next call of gzclose on the returned gzFile will also close the file
1364 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1365 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1366 mode);. The duplicated descriptor should be saved to avoid a leak, since
1367 gzdopen does not close fd if it fails. If you are using fileno() to get the
1368 file descriptor from a FILE *, then you will have to use dup() to avoid
1369 double-close()ing the file descriptor. Both gzclose() and fclose() will
1370 close the associated file descriptor, so they need to have different file
1373 gzdopen returns NULL if there was insufficient memory to allocate the
1374 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1375 provided, or '+' was provided), or if fd is -1. The file descriptor is not
1376 used until the next gz* read, write, seek, or close operation, so gzdopen
1377 will not detect if fd is invalid (unless fd is -1).
1380 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1382 Set the internal buffer size used by this library's functions for file to
1383 size. The default buffer size is 8192 bytes. This function must be called
1384 after gzopen() or gzdopen(), and before any other calls that read or write
1385 the file. The buffer memory allocation is always deferred to the first read
1386 or write. Three times that size in buffer space is allocated. A larger
1387 buffer size of, for example, 64K or 128K bytes will noticeably increase the
1388 speed of decompression (reading).
1390 The new buffer size also affects the maximum length for gzprintf().
1392 gzbuffer() returns 0 on success, or -1 on failure, such as being called
1396 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1398 Dynamically update the compression level and strategy for file. See the
1399 description of deflateInit2 for the meaning of these parameters. Previously
1400 provided data is flushed before applying the parameter changes.
1402 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
1403 opened for writing, Z_ERRNO if there is an error writing the flushed data,
1404 or Z_MEM_ERROR if there is a memory allocation error.
1407 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1409 Read and decompress up to len uncompressed bytes from file into buf. If
1410 the input file is not in gzip format, gzread copies the given number of
1411 bytes into the buffer directly from the file.
1413 After reaching the end of a gzip stream in the input, gzread will continue
1414 to read, looking for another gzip stream. Any number of gzip streams may be
1415 concatenated in the input file, and will all be decompressed by gzread().
1416 If something other than a gzip stream is encountered after a gzip stream,
1417 that remaining trailing garbage is ignored (and no error is returned).
1419 gzread can be used to read a gzip file that is being concurrently written.
1420 Upon reaching the end of the input, gzread will return with the available
1421 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1422 gzclearerr can be used to clear the end of file indicator in order to permit
1423 gzread to be tried again. Z_OK indicates that a gzip stream was completed
1424 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1425 middle of a gzip stream. Note that gzread does not return -1 in the event
1426 of an incomplete gzip stream. This error is deferred until gzclose(), which
1427 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1428 stream. Alternatively, gzerror can be used before gzclose to detect this
1431 gzread returns the number of uncompressed bytes actually read, less than
1432 len for end of file, or -1 for error. If len is too large to fit in an int,
1433 then nothing is read, -1 is returned, and the error state is set to
1437 ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems,
1440 Read and decompress up to nitems items of size size from file into buf,
1441 otherwise operating as gzread() does. This duplicates the interface of
1442 stdio's fread(), with size_t request and return types. If the library
1443 defines size_t, then z_size_t is identical to size_t. If not, then z_size_t
1444 is an unsigned integer type that can contain a pointer.
1446 gzfread() returns the number of full items read of size size, or zero if
1447 the end of the file was reached and a full item could not be read, or if
1448 there was an error. gzerror() must be consulted if zero is returned in
1449 order to determine if there was an error. If the multiplication of size and
1450 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing
1451 is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
1453 In the event that the end of file is reached and only a partial item is
1454 available at the end, i.e. the remaining uncompressed data length is not a
1455 multiple of size, then the final partial item is nevertheless read into buf
1456 and the end-of-file flag is set. The length of the partial item read is not
1457 provided, but could be inferred from the result of gztell(). This behavior
1458 is the same as the behavior of fread() implementations in common libraries,
1459 but it prevents the direct use of gzfread() to read a concurrently written
1460 file, resetting and retrying on end-of-file, when size is not 1.
1463 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, voidpc buf, unsigned len));
1465 Compress and write the len uncompressed bytes at buf to file. gzwrite
1466 returns the number of uncompressed bytes written or 0 in case of error.
1469 ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
1470 z_size_t nitems, gzFile file));
1472 Compress and write nitems items of size size from buf to file, duplicating
1473 the interface of stdio's fwrite(), with size_t request and return types. If
1474 the library defines size_t, then z_size_t is identical to size_t. If not,
1475 then z_size_t is an unsigned integer type that can contain a pointer.
1477 gzfwrite() returns the number of full items written of size size, or zero
1478 if there was an error. If the multiplication of size and nitems overflows,
1479 i.e. the product does not fit in a z_size_t, then nothing is written, zero
1480 is returned, and the error state is set to Z_STREAM_ERROR.
1483 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1485 Convert, format, compress, and write the arguments (...) to file under
1486 control of the string format, as in fprintf. gzprintf returns the number of
1487 uncompressed bytes actually written, or a negative zlib error code in case
1488 of error. The number of uncompressed bytes written is limited to 8191, or
1489 one less than the buffer size given to gzbuffer(). The caller should assure
1490 that this limit is not exceeded. If it is exceeded, then gzprintf() will
1491 return an error (0) with nothing written. In this case, there may also be a
1492 buffer overflow with unpredictable consequences, which is possible only if
1493 zlib was compiled with the insecure functions sprintf() or vsprintf(),
1494 because the secure snprintf() or vsnprintf() functions were not available.
1495 This can be determined using zlibCompileFlags().
1498 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1500 Compress and write the given null-terminated string s to file, excluding
1501 the terminating null character.
1503 gzputs returns the number of characters written, or -1 in case of error.
1506 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1508 Read and decompress bytes from file into buf, until len-1 characters are
1509 read, or until a newline character is read and transferred to buf, or an
1510 end-of-file condition is encountered. If any characters are read or if len
1511 is one, the string is terminated with a null character. If no characters
1512 are read due to an end-of-file or len is less than one, then the buffer is
1515 gzgets returns buf which is a null-terminated string, or it returns NULL
1516 for end-of-file or in case of error. If there was an error, the contents at
1517 buf are indeterminate.
1520 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1522 Compress and write c, converted to an unsigned char, into file. gzputc
1523 returns the value that was written, or -1 in case of error.
1526 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1528 Read and decompress one byte from file. gzgetc returns this byte or -1
1529 in case of end of file or error. This is implemented as a macro for speed.
1530 As such, it does not do all of the checking the other functions do. I.e.
1531 it does not check to see if file is NULL, nor whether the structure file
1532 points to has been clobbered or not.
1535 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1537 Push c back onto the stream for file to be read as the first character on
1538 the next read. At least one character of push-back is always allowed.
1539 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1540 fail if c is -1, and may fail if a character has been pushed but not read
1541 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1542 output buffer size of pushed characters is allowed. (See gzbuffer above.)
1543 The pushed character will be discarded if the stream is repositioned with
1544 gzseek() or gzrewind().
1547 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1549 Flush all pending output to file. The parameter flush is as in the
1550 deflate() function. The return value is the zlib error number (see function
1551 gzerror below). gzflush is only permitted when writing.
1553 If the flush parameter is Z_FINISH, the remaining data is written and the
1554 gzip stream is completed in the output. If gzwrite() is called again, a new
1555 gzip stream will be started in the output. gzread() is able to read such
1556 concatenated gzip streams.
1558 gzflush should be called only when strictly necessary because it will
1559 degrade compression if called too often.
1563 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1564 z_off_t offset, int whence));
1566 Set the starting position to offset relative to whence for the next gzread
1567 or gzwrite on file. The offset represents a number of bytes in the
1568 uncompressed data stream. The whence parameter is defined as in lseek(2);
1569 the value SEEK_END is not supported.
1571 If the file is opened for reading, this function is emulated but can be
1572 extremely slow. If the file is opened for writing, only forward seeks are
1573 supported; gzseek then compresses a sequence of zeroes up to the new
1576 gzseek returns the resulting offset location as measured in bytes from
1577 the beginning of the uncompressed stream, or -1 in case of error, in
1578 particular if the file is opened for writing and the new starting position
1579 would be before the current position.
1582 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
1584 Rewind file. This function is supported only for reading.
1586 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET).
1590 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
1592 Return the starting position for the next gzread or gzwrite on file.
1593 This position represents a number of bytes in the uncompressed data stream,
1594 and is zero when starting, even if appending or reading a gzip stream from
1595 the middle of a file using gzdopen().
1597 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1601 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1603 Return the current compressed (actual) read or write offset of file. This
1604 offset includes the count of bytes that precede the gzip stream, for example
1605 when appending or when using gzdopen() for reading. When reading, the
1606 offset does not include as yet unused buffered input. This information can
1607 be used for a progress indicator. On error, gzoffset() returns -1.
1610 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1612 Return true (1) if the end-of-file indicator for file has been set while
1613 reading, false (0) otherwise. Note that the end-of-file indicator is set
1614 only if the read tried to go past the end of the input, but came up short.
1615 Therefore, just like feof(), gzeof() may return false even if there is no
1616 more data to read, in the event that the last read request was for the exact
1617 number of bytes remaining in the input file. This will happen if the input
1618 file size is an exact multiple of the buffer size.
1620 If gzeof() returns true, then the read functions will return no more data,
1621 unless the end-of-file indicator is reset by gzclearerr() and the input file
1622 has grown since the previous end of file was detected.
1625 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1627 Return true (1) if file is being copied directly while reading, or false
1628 (0) if file is a gzip stream being decompressed.
1630 If the input file is empty, gzdirect() will return true, since the input
1631 does not contain a gzip stream.
1633 If gzdirect() is used immediately after gzopen() or gzdopen() it will
1634 cause buffers to be allocated to allow reading the file to determine if it
1635 is a gzip file. Therefore if gzbuffer() is used, it should be called before
1638 When writing, gzdirect() returns true (1) if transparent writing was
1639 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1640 gzdirect() is not needed when writing. Transparent writing must be
1641 explicitly requested, so the application already knows the answer. When
1642 linking statically, using gzdirect() will include all of the zlib code for
1643 gzip file reading and decompression, which may not be desired.)
1646 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
1648 Flush all pending output for file, if necessary, close file and
1649 deallocate the (de)compression state. Note that once file is closed, you
1650 cannot call gzerror with file, since its structures have been deallocated.
1651 gzclose must not be called more than once on the same file, just as free
1652 must not be called more than once on the same allocation.
1654 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1655 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1656 last read ended in the middle of a gzip stream, or Z_OK on success.
1659 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1660 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1662 Same as gzclose(), but gzclose_r() is only for use when reading, and
1663 gzclose_w() is only for use when writing or appending. The advantage to
1664 using these instead of gzclose() is that they avoid linking in zlib
1665 compression or decompression code that is not used when only reading or only
1666 writing respectively. If gzclose() is used, then both compression and
1667 decompression code will be included the application when linking to a static
1671 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1673 Return the error message for the last error which occurred on file.
1674 errnum is set to zlib error number. If an error occurred in the file system
1675 and not in the compression library, errnum is set to Z_ERRNO and the
1676 application may consult errno to get the exact error code.
1678 The application must not modify the returned string. Future calls to
1679 this function may invalidate the previously returned string. If file is
1680 closed, then the string previously returned by gzerror will no longer be
1683 gzerror() should be used to distinguish errors from end-of-file for those
1684 functions above that do not distinguish those cases in their return values.
1687 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1689 Clear the error and end-of-file flags for file. This is analogous to the
1690 clearerr() function in stdio. This is useful for continuing to read a gzip
1691 file that is being written concurrently.
1694 #endif /* !Z_SOLO */
1696 /* checksum functions */
1699 These functions are not related to compression but are exported
1700 anyway because they might be useful in applications using the compression
1704 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1706 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1707 return the updated checksum. An Adler-32 value is in the range of a 32-bit
1708 unsigned integer. If buf is Z_NULL, this function returns the required
1709 initial value for the checksum.
1711 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1716 uLong adler = adler32(0L, Z_NULL, 0);
1718 while (read_buffer(buffer, length) != EOF) {
1719 adler = adler32(adler, buffer, length);
1721 if (adler != original_adler) error();
1724 ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf,
1727 Same as adler32(), but with a size_t length.
1731 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1734 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1735 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1736 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1737 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1738 that the z_off_t type (like off_t) is a signed integer. If len2 is
1739 negative, the result has no meaning or utility.
1742 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
1744 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1745 updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer.
1746 If buf is Z_NULL, this function returns the required initial value for the
1747 crc. Pre- and post-conditioning (one's complement) is performed within this
1748 function so it shouldn't be done by the application.
1752 uLong crc = crc32(0L, Z_NULL, 0);
1754 while (read_buffer(buffer, length) != EOF) {
1755 crc = crc32(crc, buffer, length);
1757 if (crc != original_crc) error();
1760 ZEXTERN uLong ZEXPORT crc32_z OF((uLong crc, const Bytef *buf,
1763 Same as crc32(), but with a size_t length.
1767 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1769 Combine two CRC-32 check values into one. For two sequences of bytes,
1770 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1771 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1772 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1777 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t len2));
1779 Return the operator corresponding to length len2, to be used with
1785 ZEXTERN uLong ZEXPORT crc32_combine_op OF((uLong crc1, uLong crc2, uLong op));
1787 Give the same result as crc32_combine(), using op in place of len2. op is
1788 is generated from len2 by crc32_combine_gen(). This will be faster than
1789 crc32_combine() if the generated op is used more than once.
1793 /* various hacks, don't look :) */
1795 /* deflateInit and inflateInit are macros to allow checking the zlib version
1796 * and the compiler's view of z_stream:
1798 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1799 const char *version, int stream_size));
1800 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1801 const char *version, int stream_size));
1802 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
1803 int windowBits, int memLevel,
1804 int strategy, const char *version,
1806 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1807 const char *version, int stream_size));
1808 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1809 unsigned char FAR *window,
1810 const char *version,
1813 # define z_deflateInit(strm, level) \
1814 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1815 # define z_inflateInit(strm) \
1816 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1817 # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1818 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1819 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1820 # define z_inflateInit2(strm, windowBits) \
1821 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1822 (int)sizeof(z_stream))
1823 # define z_inflateBackInit(strm, windowBits, window) \
1824 inflateBackInit_((strm), (windowBits), (window), \
1825 ZLIB_VERSION, (int)sizeof(z_stream))
1827 # define deflateInit(strm, level) \
1828 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1829 # define inflateInit(strm) \
1830 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1831 # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1832 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1833 (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1834 # define inflateInit2(strm, windowBits) \
1835 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1836 (int)sizeof(z_stream))
1837 # define inflateBackInit(strm, windowBits, window) \
1838 inflateBackInit_((strm), (windowBits), (window), \
1839 ZLIB_VERSION, (int)sizeof(z_stream))
1842 #else /* Z_FREETYPE */
1845 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
1846 const char *version, int stream_size));
1848 # define inflateInit2(strm, windowBits) \
1849 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1850 (int)sizeof(z_stream))
1852 #endif /* Z_FREETYPE */
1857 /* gzgetc() macro and its supporting function and exposed data structure. Note
1858 * that the real internal state is much larger than the exposed structure.
1859 * This abbreviated structure exposes just enough for the gzgetc() macro. The
1860 * user should not mess with these exposed elements, since their names or
1861 * behavior could change in the future, perhaps even capriciously. They can
1862 * only be used by the gzgetc() macro. You have been warned.
1866 unsigned char *next;
1869 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
1872 # define z_gzgetc(g) \
1873 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1875 # define gzgetc(g) \
1876 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1879 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1880 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1881 * both are true, the application gets the *64 functions, and the regular
1882 * functions are changed to 64 bits) -- in case these are set on systems
1883 * without large file support, _LFS64_LARGEFILE must also be true
1886 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1887 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1888 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1889 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1890 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1891 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1892 ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off64_t));
1895 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1896 # ifdef Z_PREFIX_SET
1897 # define z_gzopen z_gzopen64
1898 # define z_gzseek z_gzseek64
1899 # define z_gztell z_gztell64
1900 # define z_gzoffset z_gzoffset64
1901 # define z_adler32_combine z_adler32_combine64
1902 # define z_crc32_combine z_crc32_combine64
1903 # define z_crc32_combine_gen z_crc32_combine_gen64
1905 # define gzopen gzopen64
1906 # define gzseek gzseek64
1907 # define gztell gztell64
1908 # define gzoffset gzoffset64
1909 # define adler32_combine adler32_combine64
1910 # define crc32_combine crc32_combine64
1911 # define crc32_combine_gen crc32_combine_gen64
1914 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1915 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1916 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1917 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1918 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1919 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1920 ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off_t));
1923 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1924 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1925 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1926 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1927 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1928 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1929 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t));
1935 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1936 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1937 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t));
1940 #endif /* !Z_SOLO */
1942 /* undocumented functions */
1944 ZEXTERN const char * ZEXPORT zError OF((int));
1945 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
1946 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
1947 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
1948 ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int));
1949 ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF((z_streamp));
1950 #endif /* !Z_FREETYPE */
1951 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
1953 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
1954 #if defined(_WIN32) && !defined(Z_SOLO)
1955 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
1958 #if defined(STDC) || defined(Z_HAVE_STDARG_H)
1960 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1965 #endif /* !Z_FREETYPE */
projects / platform / upstream / freetype2.git / blob