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[svn r136] MAJOR UNSTABLE UPDATE!!! Initial commit after moving to Tango instead of Phobos. Lots of bugfixes... This build is not suitable for most things.
author lindquist
date Fri, 11 Jan 2008 17:57:40 +0100
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131:5825d48b27d1 132:1700239cab2e
1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.2.3, July 18th, 2005
3
4 Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
5
6 This software is provided 'as-is', without any express or implied
7 warranty. In no event will the authors be held liable for any damages
8 arising from the use of this software.
9
10 Permission is granted to anyone to use this software for any purpose,
11 including commercial applications, and to alter it and redistribute it
12 freely, subject to the following restrictions:
13
14 1. The origin of this software must not be misrepresented; you must not
15 claim that you wrote the original software. If you use this software
16 in a product, an acknowledgment in the product documentation would be
17 appreciated but is not required.
18 2. Altered source versions must be plainly marked as such, and must not be
19 misrepresented as being the original software.
20 3. This notice may not be removed or altered from any source distribution.
21
22 Jean-loup Gailly Mark Adler
23 jloup@gzip.org madler@alumni.caltech.edu
24
25
26 The data format used by the zlib library is described by RFCs (Request for
27 Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
29 */
30
31 module tango.io.compress.c.zlib;
32
33 extern (C):
34
35 const char* ZLIB_VERSION = "1.2.3";
36 const uint ZLIB_VERNUM = 0x1230;
37
38 /*
39 The 'zlib' compression library provides in-memory compression and
40 decompression functions, including integrity checks of the uncompressed
41 data. This version of the library supports only one compression method
42 (deflation) but other algorithms will be added later and will have the same
43 stream interface.
44
45 Compression can be done in a single step if the buffers are large
46 enough (for example if an input file is mmap'ed), or can be done by
47 repeated calls of the compression function. In the latter case, the
48 application must provide more input and/or consume the output
49 (providing more output space) before each call.
50
51 The compressed data format used by default by the in-memory functions is
52 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
53 around a deflate stream, which is itself documented in RFC 1951.
54
55 The library also supports reading and writing files in gzip (.gz) format
56 with an interface similar to that of stdio using the functions that start
57 with "gz". The gzip format is different from the zlib format. gzip is a
58 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
59
60 This library can optionally read and write gzip streams in memory as well.
61
62 The zlib format was designed to be compact and fast for use in memory
63 and on communications channels. The gzip format was designed for single-
64 file compression on file systems, has a larger header than zlib to maintain
65 directory information, and uses a different, slower check method than zlib.
66
67 The library does not install any signal handler. The decoder checks
68 the consistency of the compressed data, so the library should never
69 crash even in case of corrupted input.
70 */
71
72 private
73 {
74 import tango.stdc.config : c_long, c_ulong;
75
76 version( Posix )
77 {
78 import tango.stdc.posix.sys.types : z_off_t = off_t;
79 }
80 else
81 {
82 alias c_long z_off_t;
83 }
84
85 alias ubyte Byte;
86 alias uint uInt;
87 alias c_ulong uLong;
88
89 alias Byte Bytef;
90 alias char charf;
91 alias int intf;
92 alias uInt uIntf;
93 alias uLong uLongf;
94
95 alias void* voidpc; // TODO: normally const
96 alias void* voidpf;
97 alias void* voidp;
98
99 alias voidpf function(voidpf opaque, uInt items, uInt size) alloc_func;
100 alias void function(voidpf opaque, voidpf address) free_func;
101
102 struct internal_state {}
103 }
104
105 struct z_stream
106 {
107 Bytef* next_in; /* next input byte */
108 uInt avail_in; /* number of bytes available at next_in */
109 uLong total_in; /* total nb of input bytes read so far */
110
111 Bytef* next_out; /* next output byte should be put there */
112 uInt avail_out; /* remaining free space at next_out */
113 uLong total_out; /* total nb of bytes output so far */
114
115 char* msg; /* last error message, NULL if no error */
116 internal_state* state; /* not visible by applications */
117
118 alloc_func zalloc; /* used to allocate the internal state */
119 free_func zfree; /* used to free the internal state */
120 voidpf opaque; /* private data object passed to zalloc and zfree */
121
122 int data_type; /* best guess about the data type: binary or text */
123 uLong adler; /* adler32 value of the uncompressed data */
124 uLong reserved; /* reserved for future use */
125 }
126
127 alias z_stream* z_streamp;
128
129 /*
130 gzip header information passed to and from zlib routines. See RFC 1952
131 for more details on the meanings of these fields.
132 */
133 struct gz_header
134 {
135 int text; /* true if compressed data believed to be text */
136 uLong time; /* modification time */
137 int xflags; /* extra flags (not used when writing a gzip file) */
138 int os; /* operating system */
139 Bytef* extra; /* pointer to extra field or Z_NULL if none */
140 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
141 uInt extra_max; /* space at extra (only when reading header) */
142 Bytef* name; /* pointer to zero-terminated file name or Z_NULL */
143 uInt name_max; /* space at name (only when reading header) */
144 Bytef* comment; /* pointer to zero-terminated comment or Z_NULL */
145 uInt comm_max; /* space at comment (only when reading header) */
146 int hcrc; /* true if there was or will be a header crc */
147 int done; /* true when done reading gzip header (not used
148 when writing a gzip file) */
149 }
150
151 alias gz_header* gz_headerp;
152
153 /*
154 The application must update next_in and avail_in when avail_in has
155 dropped to zero. It must update next_out and avail_out when avail_out
156 has dropped to zero. The application must initialize zalloc, zfree and
157 opaque before calling the init function. All other fields are set by the
158 compression library and must not be updated by the application.
159
160 The opaque value provided by the application will be passed as the first
161 parameter for calls of zalloc and zfree. This can be useful for custom
162 memory management. The compression library attaches no meaning to the
163 opaque value.
164
165 zalloc must return Z_NULL if there is not enough memory for the object.
166 If zlib is used in a multi-threaded application, zalloc and zfree must be
167 thread safe.
168
169 On 16-bit systems, the functions zalloc and zfree must be able to allocate
170 exactly 65536 bytes, but will not be required to allocate more than this
171 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
172 pointers returned by zalloc for objects of exactly 65536 bytes *must*
173 have their offset normalized to zero. The default allocation function
174 provided by this library ensures this (see zutil.c). To reduce memory
175 requirements and avoid any allocation of 64K objects, at the expense of
176 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
177
178 The fields total_in and total_out can be used for statistics or
179 progress reports. After compression, total_in holds the total size of
180 the uncompressed data and may be saved for use in the decompressor
181 (particularly if the decompressor wants to decompress everything in
182 a single step).
183 */
184
185 /* constants */
186
187 enum
188 {
189 Z_NO_FLUSH = 0,
190 Z_PARTIAL_FLUSH = 1, /* will be removed, use Z_SYNC_FLUSH instead */
191 Z_SYNC_FLUSH = 2,
192 Z_FULL_FLUSH = 3,
193 Z_FINISH = 4,
194 Z_BLOCK = 5,
195 }
196 /* Allowed flush values; see deflate() and inflate() below for details */
197
198 enum
199 {
200 Z_OK = 0,
201 Z_STREAM_END = 1,
202 Z_NEED_DICT = 2,
203 Z_ERRNO = -1,
204 Z_STREAM_ERROR = -2,
205 Z_DATA_ERROR = -3,
206 Z_MEM_ERROR = -4,
207 Z_BUF_ERROR = -5,
208 Z_VERSION_ERROR = -6,
209 }
210 /* Return codes for the compression/decompression functions. Negative
211 * values are errors, positive values are used for special but normal events.
212 */
213
214 enum
215 {
216 Z_NO_COMPRESSION = 0,
217 Z_BEST_SPEED = 1,
218 Z_BEST_COMPRESSION = 9,
219 Z_DEFAULT_COMPRESSION = -1,
220 }
221 /* compression levels */
222
223 enum
224 {
225 Z_FILTERED = 1,
226 Z_HUFFMAN_ONLY = 2,
227 Z_RLE = 3,
228 Z_FIXED = 4,
229 Z_DEFAULT_STRATEGY = 0,
230 }
231 /* compression strategy; see deflateInit2() below for details */
232
233 enum
234 {
235 Z_BINARY = 0,
236 Z_TEXT = 1,
237 Z_ASCII = Z_TEXT, /* for compatibility with 1.2.2 and earlier */
238 Z_UNKNOWN = 2,
239 }
240 /* Possible values of the data_type field (though see inflate()) */
241
242 enum
243 {
244 Z_DEFLATED = 8,
245 }
246 /* The deflate compression method (the only one supported in this version) */
247
248 const Z_NULL = null; /* for initializing zalloc, zfree, opaque */
249
250 alias zlibVersion zlib_version;
251 /* for compatibility with versions < 1.0.2 */
252
253 /* basic functions */
254
255 char* zlibVersion();
256 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
257 If the first character differs, the library code actually used is
258 not compatible with the zlib.h header file used by the application.
259 This check is automatically made by deflateInit and inflateInit.
260 */
261
262 /*
263 int deflateInit (z_streamp strm, int level);
264
265 Initializes the internal stream state for compression. The fields
266 zalloc, zfree and opaque must be initialized before by the caller.
267 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
268 use default allocation functions.
269
270 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
271 1 gives best speed, 9 gives best compression, 0 gives no compression at
272 all (the input data is simply copied a block at a time).
273 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
274 compression (currently equivalent to level 6).
275
276 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
277 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
278 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
279 with the version assumed by the caller (ZLIB_VERSION).
280 msg is set to null if there is no error message. deflateInit does not
281 perform any compression: this will be done by deflate().
282 */
283
284
285 int deflate(z_streamp strm, int flush);
286 /*
287 deflate compresses as much data as possible, and stops when the input
288 buffer becomes empty or the output buffer becomes full. It may introduce some
289 output latency (reading input without producing any output) except when
290 forced to flush.
291
292 The detailed semantics are as follows. deflate performs one or both of the
293 following actions:
294
295 - Compress more input starting at next_in and update next_in and avail_in
296 accordingly. If not all input can be processed (because there is not
297 enough room in the output buffer), next_in and avail_in are updated and
298 processing will resume at this point for the next call of deflate().
299
300 - Provide more output starting at next_out and update next_out and avail_out
301 accordingly. This action is forced if the parameter flush is non zero.
302 Forcing flush frequently degrades the compression ratio, so this parameter
303 should be set only when necessary (in interactive applications).
304 Some output may be provided even if flush is not set.
305
306 Before the call of deflate(), the application should ensure that at least
307 one of the actions is possible, by providing more input and/or consuming
308 more output, and updating avail_in or avail_out accordingly; avail_out
309 should never be zero before the call. The application can consume the
310 compressed output when it wants, for example when the output buffer is full
311 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
312 and with zero avail_out, it must be called again after making room in the
313 output buffer because there might be more output pending.
314
315 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
316 decide how much data to accumualte before producing output, in order to
317 maximize compression.
318
319 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
320 flushed to the output buffer and the output is aligned on a byte boundary, so
321 that the decompressor can get all input data available so far. (In particular
322 avail_in is zero after the call if enough output space has been provided
323 before the call.) Flushing may degrade compression for some compression
324 algorithms and so it should be used only when necessary.
325
326 If flush is set to Z_FULL_FLUSH, all output is flushed as with
327 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
328 restart from this point if previous compressed data has been damaged or if
329 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
330 compression.
331
332 If deflate returns with avail_out == 0, this function must be called again
333 with the same value of the flush parameter and more output space (updated
334 avail_out), until the flush is complete (deflate returns with non-zero
335 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
336 avail_out is greater than six to avoid repeated flush markers due to
337 avail_out == 0 on return.
338
339 If the parameter flush is set to Z_FINISH, pending input is processed,
340 pending output is flushed and deflate returns with Z_STREAM_END if there
341 was enough output space; if deflate returns with Z_OK, this function must be
342 called again with Z_FINISH and more output space (updated avail_out) but no
343 more input data, until it returns with Z_STREAM_END or an error. After
344 deflate has returned Z_STREAM_END, the only possible operations on the
345 stream are deflateReset or deflateEnd.
346
347 Z_FINISH can be used immediately after deflateInit if all the compression
348 is to be done in a single step. In this case, avail_out must be at least
349 the value returned by deflateBound (see below). If deflate does not return
350 Z_STREAM_END, then it must be called again as described above.
351
352 deflate() sets strm->adler to the adler32 checksum of all input read
353 so far (that is, total_in bytes).
354
355 deflate() may update strm->data_type if it can make a good guess about
356 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
357 binary. This field is only for information purposes and does not affect
358 the compression algorithm in any manner.
359
360 deflate() returns Z_OK if some progress has been made (more input
361 processed or more output produced), Z_STREAM_END if all input has been
362 consumed and all output has been produced (only when flush is set to
363 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
364 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
365 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
366 fatal, and deflate() can be called again with more input and more output
367 space to continue compressing.
368 */
369
370
371 int deflateEnd(z_streamp strm);
372 /*
373 All dynamically allocated data structures for this stream are freed.
374 This function discards any unprocessed input and does not flush any
375 pending output.
376
377 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
378 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
379 prematurely (some input or output was discarded). In the error case,
380 msg may be set but then points to a static string (which must not be
381 deallocated).
382 */
383
384
385 /*
386 int inflateInit(z_streamp strm);
387
388 Initializes the internal stream state for decompression. The fields
389 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
390 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
391 value depends on the compression method), inflateInit determines the
392 compression method from the zlib header and allocates all data structures
393 accordingly; otherwise the allocation will be deferred to the first call of
394 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
395 use default allocation functions.
396
397 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
398 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
399 version assumed by the caller. msg is set to null if there is no error
400 message. inflateInit does not perform any decompression apart from reading
401 the zlib header if present: this will be done by inflate(). (So next_in and
402 avail_in may be modified, but next_out and avail_out are unchanged.)
403 */
404
405
406 int inflate(z_streamp strm, int flush);
407 /*
408 inflate decompresses as much data as possible, and stops when the input
409 buffer becomes empty or the output buffer becomes full. It may introduce
410 some output latency (reading input without producing any output) except when
411 forced to flush.
412
413 The detailed semantics are as follows. inflate performs one or both of the
414 following actions:
415
416 - Decompress more input starting at next_in and update next_in and avail_in
417 accordingly. If not all input can be processed (because there is not
418 enough room in the output buffer), next_in is updated and processing
419 will resume at this point for the next call of inflate().
420
421 - Provide more output starting at next_out and update next_out and avail_out
422 accordingly. inflate() provides as much output as possible, until there
423 is no more input data or no more space in the output buffer (see below
424 about the flush parameter).
425
426 Before the call of inflate(), the application should ensure that at least
427 one of the actions is possible, by providing more input and/or consuming
428 more output, and updating the next_* and avail_* values accordingly.
429 The application can consume the uncompressed output when it wants, for
430 example when the output buffer is full (avail_out == 0), or after each
431 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
432 must be called again after making room in the output buffer because there
433 might be more output pending.
434
435 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
436 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
437 output as possible to the output buffer. Z_BLOCK requests that inflate() stop
438 if and when it gets to the next deflate block boundary. When decoding the
439 zlib or gzip format, this will cause inflate() to return immediately after
440 the header and before the first block. When doing a raw inflate, inflate()
441 will go ahead and process the first block, and will return when it gets to
442 the end of that block, or when it runs out of data.
443
444 The Z_BLOCK option assists in appending to or combining deflate streams.
445 Also to assist in this, on return inflate() will set strm->data_type to the
446 number of unused bits in the last byte taken from strm->next_in, plus 64
447 if inflate() is currently decoding the last block in the deflate stream,
448 plus 128 if inflate() returned immediately after decoding an end-of-block
449 code or decoding the complete header up to just before the first byte of the
450 deflate stream. The end-of-block will not be indicated until all of the
451 uncompressed data from that block has been written to strm->next_out. The
452 number of unused bits may in general be greater than seven, except when
453 bit 7 of data_type is set, in which case the number of unused bits will be
454 less than eight.
455
456 inflate() should normally be called until it returns Z_STREAM_END or an
457 error. However if all decompression is to be performed in a single step
458 (a single call of inflate), the parameter flush should be set to
459 Z_FINISH. In this case all pending input is processed and all pending
460 output is flushed; avail_out must be large enough to hold all the
461 uncompressed data. (The size of the uncompressed data may have been saved
462 by the compressor for this purpose.) The next operation on this stream must
463 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
464 is never required, but can be used to inform inflate that a faster approach
465 may be used for the single inflate() call.
466
467 In this implementation, inflate() always flushes as much output as
468 possible to the output buffer, and always uses the faster approach on the
469 first call. So the only effect of the flush parameter in this implementation
470 is on the return value of inflate(), as noted below, or when it returns early
471 because Z_BLOCK is used.
472
473 If a preset dictionary is needed after this call (see inflateSetDictionary
474 below), inflate sets strm->adler to the adler32 checksum of the dictionary
475 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
476 strm->adler to the adler32 checksum of all output produced so far (that is,
477 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
478 below. At the end of the stream, inflate() checks that its computed adler32
479 checksum is equal to that saved by the compressor and returns Z_STREAM_END
480 only if the checksum is correct.
481
482 inflate() will decompress and check either zlib-wrapped or gzip-wrapped
483 deflate data. The header type is detected automatically. Any information
484 contained in the gzip header is not retained, so applications that need that
485 information should instead use raw inflate, see inflateInit2() below, or
486 inflateBack() and perform their own processing of the gzip header and
487 trailer.
488
489 inflate() returns Z_OK if some progress has been made (more input processed
490 or more output produced), Z_STREAM_END if the end of the compressed data has
491 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
492 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
493 corrupted (input stream not conforming to the zlib format or incorrect check
494 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
495 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
496 Z_BUF_ERROR if no progress is possible or if there was not enough room in the
497 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
498 inflate() can be called again with more input and more output space to
499 continue decompressing. If Z_DATA_ERROR is returned, the application may then
500 call inflateSync() to look for a good compression block if a partial recovery
501 of the data is desired.
502 */
503
504
505 int inflateEnd(z_streamp strm);
506 /*
507 All dynamically allocated data structures for this stream are freed.
508 This function discards any unprocessed input and does not flush any
509 pending output.
510
511 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
512 was inconsistent. In the error case, msg may be set but then points to a
513 static string (which must not be deallocated).
514 */
515
516 /* Advanced functions */
517
518 /*
519 The following functions are needed only in some special applications.
520 */
521
522 /*
523 int deflateInit2 (z_streamp strm,
524 int level,
525 int method,
526 int windowBits,
527 int memLevel,
528 int strategy);
529
530 This is another version of deflateInit with more compression options. The
531 fields next_in, zalloc, zfree and opaque must be initialized before by
532 the caller.
533
534 The method parameter is the compression method. It must be Z_DEFLATED in
535 this version of the library.
536
537 The windowBits parameter is the base two logarithm of the window size
538 (the size of the history buffer). It should be in the range 8..15 for this
539 version of the library. Larger values of this parameter result in better
540 compression at the expense of memory usage. The default value is 15 if
541 deflateInit is used instead.
542
543 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
544 determines the window size. deflate() will then generate raw deflate data
545 with no zlib header or trailer, and will not compute an adler32 check value.
546
547 windowBits can also be greater than 15 for optional gzip encoding. Add
548 16 to windowBits to write a simple gzip header and trailer around the
549 compressed data instead of a zlib wrapper. The gzip header will have no
550 file name, no extra data, no comment, no modification time (set to zero),
551 no header crc, and the operating system will be set to 255 (unknown). If a
552 gzip stream is being written, strm->adler is a crc32 instead of an adler32.
553
554 The memLevel parameter specifies how much memory should be allocated
555 for the internal compression state. memLevel=1 uses minimum memory but
556 is slow and reduces compression ratio; memLevel=9 uses maximum memory
557 for optimal speed. The default value is 8. See zconf.h for total memory
558 usage as a function of windowBits and memLevel.
559
560 The strategy parameter is used to tune the compression algorithm. Use the
561 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
562 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
563 string match), or Z_RLE to limit match distances to one (run-length
564 encoding). Filtered data consists mostly of small values with a somewhat
565 random distribution. In this case, the compression algorithm is tuned to
566 compress them better. The effect of Z_FILTERED is to force more Huffman
567 coding and less string matching; it is somewhat intermediate between
568 Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
569 Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
570 parameter only affects the compression ratio but not the correctness of the
571 compressed output even if it is not set appropriately. Z_FIXED prevents the
572 use of dynamic Huffman codes, allowing for a simpler decoder for special
573 applications.
574
575 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
576 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
577 method). msg is set to null if there is no error message. deflateInit2 does
578 not perform any compression: this will be done by deflate().
579 */
580
581 int deflateSetDictionary(z_streamp strm,
582 Bytef* dictionary,
583 uInt dictLength);
584 /*
585 Initializes the compression dictionary from the given byte sequence
586 without producing any compressed output. This function must be called
587 immediately after deflateInit, deflateInit2 or deflateReset, before any
588 call of deflate. The compressor and decompressor must use exactly the same
589 dictionary (see inflateSetDictionary).
590
591 The dictionary should consist of strings (byte sequences) that are likely
592 to be encountered later in the data to be compressed, with the most commonly
593 used strings preferably put towards the end of the dictionary. Using a
594 dictionary is most useful when the data to be compressed is short and can be
595 predicted with good accuracy; the data can then be compressed better than
596 with the default empty dictionary.
597
598 Depending on the size of the compression data structures selected by
599 deflateInit or deflateInit2, a part of the dictionary may in effect be
600 discarded, for example if the dictionary is larger than the window size in
601 deflate or deflate2. Thus the strings most likely to be useful should be
602 put at the end of the dictionary, not at the front. In addition, the
603 current implementation of deflate will use at most the window size minus
604 262 bytes of the provided dictionary.
605
606 Upon return of this function, strm->adler is set to the adler32 value
607 of the dictionary; the decompressor may later use this value to determine
608 which dictionary has been used by the compressor. (The adler32 value
609 applies to the whole dictionary even if only a subset of the dictionary is
610 actually used by the compressor.) If a raw deflate was requested, then the
611 adler32 value is not computed and strm->adler is not set.
612
613 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
614 parameter is invalid (such as NULL dictionary) or the stream state is
615 inconsistent (for example if deflate has already been called for this stream
616 or if the compression method is bsort). deflateSetDictionary does not
617 perform any compression: this will be done by deflate().
618 */
619
620 int deflateCopy(z_streamp dest,
621 z_streamp source);
622 /*
623 Sets the destination stream as a complete copy of the source stream.
624
625 This function can be useful when several compression strategies will be
626 tried, for example when there are several ways of pre-processing the input
627 data with a filter. The streams that will be discarded should then be freed
628 by calling deflateEnd. Note that deflateCopy duplicates the internal
629 compression state which can be quite large, so this strategy is slow and
630 can consume lots of memory.
631
632 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
633 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
634 (such as zalloc being NULL). msg is left unchanged in both source and
635 destination.
636 */
637
638 int deflateReset(z_streamp strm);
639 /*
640 This function is equivalent to deflateEnd followed by deflateInit,
641 but does not free and reallocate all the internal compression state.
642 The stream will keep the same compression level and any other attributes
643 that may have been set by deflateInit2.
644
645 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
646 stream state was inconsistent (such as zalloc or state being NULL).
647 */
648
649 int deflateParams(z_streamp strm,
650 int level,
651 int strategy);
652 /*
653 Dynamically update the compression level and compression strategy. The
654 interpretation of level and strategy is as in deflateInit2. This can be
655 used to switch between compression and straight copy of the input data, or
656 to switch to a different kind of input data requiring a different
657 strategy. If the compression level is changed, the input available so far
658 is compressed with the old level (and may be flushed); the new level will
659 take effect only at the next call of deflate().
660
661 Before the call of deflateParams, the stream state must be set as for
662 a call of deflate(), since the currently available input may have to
663 be compressed and flushed. In particular, strm->avail_out must be non-zero.
664
665 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
666 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
667 if strm->avail_out was zero.
668 */
669
670 int deflateTune(z_streamp strm,
671 int good_length,
672 int max_lazy,
673 int nice_length,
674 int max_chain);
675 /*
676 Fine tune deflate's internal compression parameters. This should only be
677 used by someone who understands the algorithm used by zlib's deflate for
678 searching for the best matching string, and even then only by the most
679 fanatic optimizer trying to squeeze out the last compressed bit for their
680 specific input data. Read the deflate.c source code for the meaning of the
681 max_lazy, good_length, nice_length, and max_chain parameters.
682
683 deflateTune() can be called after deflateInit() or deflateInit2(), and
684 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
685 */
686
687 uLong deflateBound(z_streamp strm,
688 uLong sourceLen);
689 /*
690 deflateBound() returns an upper bound on the compressed size after
691 deflation of sourceLen bytes. It must be called after deflateInit()
692 or deflateInit2(). This would be used to allocate an output buffer
693 for deflation in a single pass, and so would be called before deflate().
694 */
695
696 int deflatePrime(z_streamp strm,
697 int bits,
698 int value);
699 /*
700 deflatePrime() inserts bits in the deflate output stream. The intent
701 is that this function is used to start off the deflate output with the
702 bits leftover from a previous deflate stream when appending to it. As such,
703 this function can only be used for raw deflate, and must be used before the
704 first deflate() call after a deflateInit2() or deflateReset(). bits must be
705 less than or equal to 16, and that many of the least significant bits of
706 value will be inserted in the output.
707
708 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
709 stream state was inconsistent.
710 */
711
712 int deflateSetHeader(z_streamp strm,
713 gz_headerp head);
714 /*
715 deflateSetHeader() provides gzip header information for when a gzip
716 stream is requested by deflateInit2(). deflateSetHeader() may be called
717 after deflateInit2() or deflateReset() and before the first call of
718 deflate(). The text, time, os, extra field, name, and comment information
719 in the provided gz_header structure are written to the gzip header (xflag is
720 ignored -- the extra flags are set according to the compression level). The
721 caller must assure that, if not Z_NULL, name and comment are terminated with
722 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
723 available there. If hcrc is true, a gzip header crc is included. Note that
724 the current versions of the command-line version of gzip (up through version
725 1.3.x) do not support header crc's, and will report that it is a "multi-part
726 gzip file" and give up.
727
728 If deflateSetHeader is not used, the default gzip header has text false,
729 the time set to zero, and os set to 255, with no extra, name, or comment
730 fields. The gzip header is returned to the default state by deflateReset().
731
732 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
733 stream state was inconsistent.
734 */
735
736 /*
737 int inflateInit2(z_streamp strm,
738 int windowBits);
739
740 This is another version of inflateInit with an extra parameter. The
741 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
742 before by the caller.
743
744 The windowBits parameter is the base two logarithm of the maximum window
745 size (the size of the history buffer). It should be in the range 8..15 for
746 this version of the library. The default value is 15 if inflateInit is used
747 instead. windowBits must be greater than or equal to the windowBits value
748 provided to deflateInit2() while compressing, or it must be equal to 15 if
749 deflateInit2() was not used. If a compressed stream with a larger window
750 size is given as input, inflate() will return with the error code
751 Z_DATA_ERROR instead of trying to allocate a larger window.
752
753 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
754 determines the window size. inflate() will then process raw deflate data,
755 not looking for a zlib or gzip header, not generating a check value, and not
756 looking for any check values for comparison at the end of the stream. This
757 is for use with other formats that use the deflate compressed data format
758 such as zip. Those formats provide their own check values. If a custom
759 format is developed using the raw deflate format for compressed data, it is
760 recommended that a check value such as an adler32 or a crc32 be applied to
761 the uncompressed data as is done in the zlib, gzip, and zip formats. For
762 most applications, the zlib format should be used as is. Note that comments
763 above on the use in deflateInit2() applies to the magnitude of windowBits.
764
765 windowBits can also be greater than 15 for optional gzip decoding. Add
766 32 to windowBits to enable zlib and gzip decoding with automatic header
767 detection, or add 16 to decode only the gzip format (the zlib format will
768 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
769 a crc32 instead of an adler32.
770
771 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
772 memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
773 is set to null if there is no error message. inflateInit2 does not perform
774 any decompression apart from reading the zlib header if present: this will
775 be done by inflate(). (So next_in and avail_in may be modified, but next_out
776 and avail_out are unchanged.)
777 */
778
779 int inflateSetDictionary(z_streamp strm,
780 Bytef* dictionary,
781 uInt dictLength);
782 /*
783 Initializes the decompression dictionary from the given uncompressed byte
784 sequence. This function must be called immediately after a call of inflate,
785 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
786 can be determined from the adler32 value returned by that call of inflate.
787 The compressor and decompressor must use exactly the same dictionary (see
788 deflateSetDictionary). For raw inflate, this function can be called
789 immediately after inflateInit2() or inflateReset() and before any call of
790 inflate() to set the dictionary. The application must insure that the
791 dictionary that was used for compression is provided.
792
793 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
794 parameter is invalid (such as NULL dictionary) or the stream state is
795 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
796 expected one (incorrect adler32 value). inflateSetDictionary does not
797 perform any decompression: this will be done by subsequent calls of
798 inflate().
799 */
800
801 int inflateSync(z_streamp strm);
802 /*
803 Skips invalid compressed data until a full flush point (see above the
804 description of deflate with Z_FULL_FLUSH) can be found, or until all
805 available input is skipped. No output is provided.
806
807 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
808 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
809 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
810 case, the application may save the current current value of total_in which
811 indicates where valid compressed data was found. In the error case, the
812 application may repeatedly call inflateSync, providing more input each time,
813 until success or end of the input data.
814 */
815
816 int inflateCopy(z_streamp dest,
817 z_streamp source);
818 /*
819 Sets the destination stream as a complete copy of the source stream.
820
821 This function can be useful when randomly accessing a large stream. The
822 first pass through the stream can periodically record the inflate state,
823 allowing restarting inflate at those points when randomly accessing the
824 stream.
825
826 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
827 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
828 (such as zalloc being NULL). msg is left unchanged in both source and
829 destination.
830 */
831
832 int inflateReset(z_streamp strm);
833 /*
834 This function is equivalent to inflateEnd followed by inflateInit,
835 but does not free and reallocate all the internal decompression state.
836 The stream will keep attributes that may have been set by inflateInit2.
837
838 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
839 stream state was inconsistent (such as zalloc or state being NULL).
840 */
841
842 int inflatePrime(z_streamp strm,
843 int bits,
844 int value);
845 /*
846 This function inserts bits in the inflate input stream. The intent is
847 that this function is used to start inflating at a bit position in the
848 middle of a byte. The provided bits will be used before any bytes are used
849 from next_in. This function should only be used with raw inflate, and
850 should be used before the first inflate() call after inflateInit2() or
851 inflateReset(). bits must be less than or equal to 16, and that many of the
852 least significant bits of value will be inserted in the input.
853
854 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
855 stream state was inconsistent.
856 */
857
858 int inflateGetHeader(z_streamp strm,
859 gz_headerp head);
860 /*
861 inflateGetHeader() requests that gzip header information be stored in the
862 provided gz_header structure. inflateGetHeader() may be called after
863 inflateInit2() or inflateReset(), and before the first call of inflate().
864 As inflate() processes the gzip stream, head->done is zero until the header
865 is completed, at which time head->done is set to one. If a zlib stream is
866 being decoded, then head->done is set to -1 to indicate that there will be
867 no gzip header information forthcoming. Note that Z_BLOCK can be used to
868 force inflate() to return immediately after header processing is complete
869 and before any actual data is decompressed.
870
871 The text, time, xflags, and os fields are filled in with the gzip header
872 contents. hcrc is set to true if there is a header CRC. (The header CRC
873 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
874 contains the maximum number of bytes to write to extra. Once done is true,
875 extra_len contains the actual extra field length, and extra contains the
876 extra field, or that field truncated if extra_max is less than extra_len.
877 If name is not Z_NULL, then up to name_max characters are written there,
878 terminated with a zero unless the length is greater than name_max. If
879 comment is not Z_NULL, then up to comm_max characters are written there,
880 terminated with a zero unless the length is greater than comm_max. When
881 any of extra, name, or comment are not Z_NULL and the respective field is
882 not present in the header, then that field is set to Z_NULL to signal its
883 absence. This allows the use of deflateSetHeader() with the returned
884 structure to duplicate the header. However if those fields are set to
885 allocated memory, then the application will need to save those pointers
886 elsewhere so that they can be eventually freed.
887
888 If inflateGetHeader is not used, then the header information is simply
889 discarded. The header is always checked for validity, including the header
890 CRC if present. inflateReset() will reset the process to discard the header
891 information. The application would need to call inflateGetHeader() again to
892 retrieve the header from the next gzip stream.
893
894 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
895 stream state was inconsistent.
896 */
897
898 /*
899 int inflateBackInit(z_streamp strm,
900 int windowBits,
901 ubyte* window);
902
903 Initialize the internal stream state for decompression using inflateBack()
904 calls. The fields zalloc, zfree and opaque in strm must be initialized
905 before the call. If zalloc and zfree are Z_NULL, then the default library-
906 derived memory allocation routines are used. windowBits is the base two
907 logarithm of the window size, in the range 8..15. window is a caller
908 supplied buffer of that size. Except for special applications where it is
909 assured that deflate was used with small window sizes, windowBits must be 15
910 and a 32K byte window must be supplied to be able to decompress general
911 deflate streams.
912
913 See inflateBack() for the usage of these routines.
914
915 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
916 the paramaters are invalid, Z_MEM_ERROR if the internal state could not
917 be allocated, or Z_VERSION_ERROR if the version of the library does not
918 match the version of the header file.
919 */
920
921 alias uint function(void*, ubyte**) in_func;
922 alias int function(void*, ubyte*, uint) out_func;
923
924 int inflateBack(z_streamp strm,
925 in_func in_fn,
926 void* in_desc,
927 out_func out_fn,
928 void* out_desc);
929 /*
930 inflateBack() does a raw inflate with a single call using a call-back
931 interface for input and output. This is more efficient than inflate() for
932 file i/o applications in that it avoids copying between the output and the
933 sliding window by simply making the window itself the output buffer. This
934 function trusts the application to not change the output buffer passed by
935 the output function, at least until inflateBack() returns.
936
937 inflateBackInit() must be called first to allocate the internal state
938 and to initialize the state with the user-provided window buffer.
939 inflateBack() may then be used multiple times to inflate a complete, raw
940 deflate stream with each call. inflateBackEnd() is then called to free
941 the allocated state.
942
943 A raw deflate stream is one with no zlib or gzip header or trailer.
944 This routine would normally be used in a utility that reads zip or gzip
945 files and writes out uncompressed files. The utility would decode the
946 header and process the trailer on its own, hence this routine expects
947 only the raw deflate stream to decompress. This is different from the
948 normal behavior of inflate(), which expects either a zlib or gzip header and
949 trailer around the deflate stream.
950
951 inflateBack() uses two subroutines supplied by the caller that are then
952 called by inflateBack() for input and output. inflateBack() calls those
953 routines until it reads a complete deflate stream and writes out all of the
954 uncompressed data, or until it encounters an error. The function's
955 parameters and return types are defined above in the in_func and out_func
956 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
957 number of bytes of provided input, and a pointer to that input in buf. If
958 there is no input available, in() must return zero--buf is ignored in that
959 case--and inflateBack() will return a buffer error. inflateBack() will call
960 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
961 should return zero on success, or non-zero on failure. If out() returns
962 non-zero, inflateBack() will return with an error. Neither in() nor out()
963 are permitted to change the contents of the window provided to
964 inflateBackInit(), which is also the buffer that out() uses to write from.
965 The length written by out() will be at most the window size. Any non-zero
966 amount of input may be provided by in().
967
968 For convenience, inflateBack() can be provided input on the first call by
969 setting strm->next_in and strm->avail_in. If that input is exhausted, then
970 in() will be called. Therefore strm->next_in must be initialized before
971 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
972 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
973 must also be initialized, and then if strm->avail_in is not zero, input will
974 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
975
976 The in_desc and out_desc parameters of inflateBack() is passed as the
977 first parameter of in() and out() respectively when they are called. These
978 descriptors can be optionally used to pass any information that the caller-
979 supplied in() and out() functions need to do their job.
980
981 On return, inflateBack() will set strm->next_in and strm->avail_in to
982 pass back any unused input that was provided by the last in() call. The
983 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
984 if in() or out() returned an error, Z_DATA_ERROR if there was a format
985 error in the deflate stream (in which case strm->msg is set to indicate the
986 nature of the error), or Z_STREAM_ERROR if the stream was not properly
987 initialized. In the case of Z_BUF_ERROR, an input or output error can be
988 distinguished using strm->next_in which will be Z_NULL only if in() returned
989 an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
990 out() returning non-zero. (in() will always be called before out(), so
991 strm->next_in is assured to be defined if out() returns non-zero.) Note
992 that inflateBack() cannot return Z_OK.
993 */
994
995 int inflateBackEnd(z_streamp strm);
996 /*
997 All memory allocated by inflateBackInit() is freed.
998
999 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1000 state was inconsistent.
1001 */
1002
1003 uLong zlibCompileFlags();
1004 /* Return flags indicating compile-time options.
1005
1006 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1007 1.0: size of uInt
1008 3.2: size of uLong
1009 5.4: size of voidpf (pointer)
1010 7.6: size of z_off_t
1011
1012 Compiler, assembler, and debug options:
1013 8: DEBUG
1014 9: ASMV or ASMINF -- use ASM code
1015 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1016 11: 0 (reserved)
1017
1018 One-time table building (smaller code, but not thread-safe if true):
1019 12: BUILDFIXED -- build static block decoding tables when needed
1020 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1021 14,15: 0 (reserved)
1022
1023 Library content (indicates missing functionality):
1024 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1025 deflate code when not needed)
1026 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1027 and decode gzip streams (to avoid linking crc code)
1028 18-19: 0 (reserved)
1029
1030 Operation variations (changes in library functionality):
1031 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1032 21: FASTEST -- deflate algorithm with only one, lowest compression level
1033 22,23: 0 (reserved)
1034
1035 The sprintf variant used by gzprintf (zero is best):
1036 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1037 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1038 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1039
1040 Remainder:
1041 27-31: 0 (reserved)
1042 */
1043
1044
1045 /* utility functions */
1046
1047 /*
1048 The following utility functions are implemented on top of the
1049 basic stream-oriented functions. To simplify the interface, some
1050 default options are assumed (compression level and memory usage,
1051 standard memory allocation functions). The source code of these
1052 utility functions can easily be modified if you need special options.
1053 */
1054
1055 int compress(Bytef* dest,
1056 uLongf* destLen,
1057 Bytef* source,
1058 uLong sourceLen);
1059 /*
1060 Compresses the source buffer into the destination buffer. sourceLen is
1061 the byte length of the source buffer. Upon entry, destLen is the total
1062 size of the destination buffer, which must be at least the value returned
1063 by compressBound(sourceLen). Upon exit, destLen is the actual size of the
1064 compressed buffer.
1065 This function can be used to compress a whole file at once if the
1066 input file is mmap'ed.
1067 compress returns Z_OK if success, Z_MEM_ERROR if there was not
1068 enough memory, Z_BUF_ERROR if there was not enough room in the output
1069 buffer.
1070 */
1071
1072 int compress2(Bytef* dest,
1073 uLongf* destLen,
1074 Bytef* source,
1075 uLong sourceLen,
1076 int level);
1077 /*
1078 Compresses the source buffer into the destination buffer. The level
1079 parameter has the same meaning as in deflateInit. sourceLen is the byte
1080 length of the source buffer. Upon entry, destLen is the total size of the
1081 destination buffer, which must be at least the value returned by
1082 compressBound(sourceLen). Upon exit, destLen is the actual size of the
1083 compressed buffer.
1084
1085 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1086 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1087 Z_STREAM_ERROR if the level parameter is invalid.
1088 */
1089
1090 uLong compressBound(uLong sourceLen);
1091 /*
1092 compressBound() returns an upper bound on the compressed size after
1093 compress() or compress2() on sourceLen bytes. It would be used before
1094 a compress() or compress2() call to allocate the destination buffer.
1095 */
1096
1097 int uncompress(Bytef* dest,
1098 uLongf* destLen,
1099 Bytef* source,
1100 uLong sourceLen);
1101 /*
1102 Decompresses the source buffer into the destination buffer. sourceLen is
1103 the byte length of the source buffer. Upon entry, destLen is the total
1104 size of the destination buffer, which must be large enough to hold the
1105 entire uncompressed data. (The size of the uncompressed data must have
1106 been saved previously by the compressor and transmitted to the decompressor
1107 by some mechanism outside the scope of this compression library.)
1108 Upon exit, destLen is the actual size of the compressed buffer.
1109 This function can be used to decompress a whole file at once if the
1110 input file is mmap'ed.
1111
1112 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1113 enough memory, Z_BUF_ERROR if there was not enough room in the output
1114 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
1115 */
1116
1117
1118 typedef voidp gzFile;
1119
1120 gzFile gzopen(char* path, char* mode);
1121 /*
1122 Opens a gzip (.gz) file for reading or writing. The mode parameter
1123 is as in fopen ("rb" or "wb") but can also include a compression level
1124 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
1125 Huffman only compression as in "wb1h", or 'R' for run-length encoding
1126 as in "wb1R". (See the description of deflateInit2 for more information
1127 about the strategy parameter.)
1128
1129 gzopen can be used to read a file which is not in gzip format; in this
1130 case gzread will directly read from the file without decompression.
1131
1132 gzopen returns NULL if the file could not be opened or if there was
1133 insufficient memory to allocate the (de)compression state; errno
1134 can be checked to distinguish the two cases (if errno is zero, the
1135 zlib error is Z_MEM_ERROR). */
1136
1137 gzFile gzdopen(int fd, char* mode);
1138 /*
1139 gzdopen() associates a gzFile with the file descriptor fd. File
1140 descriptors are obtained from calls like open, dup, creat, pipe or
1141 fileno (in the file has been previously opened with fopen).
1142 The mode parameter is as in gzopen.
1143 The next call of gzclose on the returned gzFile will also close the
1144 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
1145 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
1146 gzdopen returns NULL if there was insufficient memory to allocate
1147 the (de)compression state.
1148 */
1149
1150 int gzsetparams(gzFile file, int level, int strategy);
1151 /*
1152 Dynamically update the compression level or strategy. See the description
1153 of deflateInit2 for the meaning of these parameters.
1154 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1155 opened for writing.
1156 */
1157
1158 int gzread(gzFile file, voidp buf, uint len);
1159 /*
1160 Reads the given number of uncompressed bytes from the compressed file.
1161 If the input file was not in gzip format, gzread copies the given number
1162 of bytes into the buffer.
1163 gzread returns the number of uncompressed bytes actually read (0 for
1164 end of file, -1 for error). */
1165
1166 int gzwrite(gzFile file, voidpc buf, uint len);
1167 /*
1168 Writes the given number of uncompressed bytes into the compressed file.
1169 gzwrite returns the number of uncompressed bytes actually written
1170 (0 in case of error).
1171 */
1172
1173 int gzprintf (gzFile file, char* format, ...);
1174 /*
1175 Converts, formats, and writes the args to the compressed file under
1176 control of the format string, as in fprintf. gzprintf returns the number of
1177 uncompressed bytes actually written (0 in case of error). The number of
1178 uncompressed bytes written is limited to 4095. The caller should assure that
1179 this limit is not exceeded. If it is exceeded, then gzprintf() will return
1180 return an error (0) with nothing written. In this case, there may also be a
1181 buffer overflow with unpredictable consequences, which is possible only if
1182 zlib was compiled with the insecure functions sprintf() or vsprintf()
1183 because the secure snprintf() or vsnprintf() functions were not available.
1184 */
1185
1186 int gzputs(gzFile file, char* s);
1187 /*
1188 Writes the given null-terminated string to the compressed file, excluding
1189 the terminating null character.
1190 gzputs returns the number of characters written, or -1 in case of error.
1191 */
1192
1193 char* gzgets(gzFile file, char* buf, int len);
1194 /*
1195 Reads bytes from the compressed file until len-1 characters are read, or
1196 a newline character is read and transferred to buf, or an end-of-file
1197 condition is encountered. The string is then terminated with a null
1198 character.
1199 gzgets returns buf, or Z_NULL in case of error.
1200 */
1201
1202 int gzputc(gzFile file, int c);
1203 /*
1204 Writes c, converted to an unsigned char, into the compressed file.
1205 gzputc returns the value that was written, or -1 in case of error.
1206 */
1207
1208 int gzgetc (gzFile file);
1209 /*
1210 Reads one byte from the compressed file. gzgetc returns this byte
1211 or -1 in case of end of file or error.
1212 */
1213
1214 int gzungetc(int c, gzFile file);
1215 /*
1216 Push one character back onto the stream to be read again later.
1217 Only one character of push-back is allowed. gzungetc() returns the
1218 character pushed, or -1 on failure. gzungetc() will fail if a
1219 character has been pushed but not read yet, or if c is -1. The pushed
1220 character will be discarded if the stream is repositioned with gzseek()
1221 or gzrewind().
1222 */
1223
1224 int gzflush(gzFile file, int flush);
1225 /*
1226 Flushes all pending output into the compressed file. The parameter
1227 flush is as in the deflate() function. The return value is the zlib
1228 error number (see function gzerror below). gzflush returns Z_OK if
1229 the flush parameter is Z_FINISH and all output could be flushed.
1230 gzflush should be called only when strictly necessary because it can
1231 degrade compression.
1232 */
1233
1234 z_off_t gzseek (gzFile file, z_off_t offset, int whence);
1235 /*
1236 Sets the starting position for the next gzread or gzwrite on the
1237 given compressed file. The offset represents a number of bytes in the
1238 uncompressed data stream. The whence parameter is defined as in lseek(2);
1239 the value SEEK_END is not supported.
1240 If the file is opened for reading, this function is emulated but can be
1241 extremely slow. If the file is opened for writing, only forward seeks are
1242 supported; gzseek then compresses a sequence of zeroes up to the new
1243 starting position.
1244
1245 gzseek returns the resulting offset location as measured in bytes from
1246 the beginning of the uncompressed stream, or -1 in case of error, in
1247 particular if the file is opened for writing and the new starting position
1248 would be before the current position.
1249 */
1250
1251 int gzrewind(gzFile file);
1252 /*
1253 Rewinds the given file. This function is supported only for reading.
1254
1255 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1256 */
1257
1258 z_off_t gztell (gzFile file);
1259 /*
1260 Returns the starting position for the next gzread or gzwrite on the
1261 given compressed file. This position represents a number of bytes in the
1262 uncompressed data stream.
1263
1264 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1265 */
1266
1267 int gzeof(gzFile file);
1268 /*
1269 Returns 1 when EOF has previously been detected reading the given
1270 input stream, otherwise zero.
1271 */
1272
1273 int gzdirect(gzFile file);
1274 /*
1275 Returns 1 if file is being read directly without decompression, otherwise
1276 zero.
1277 */
1278
1279 int gzclose(gzFile file);
1280 /*
1281 Flushes all pending output if necessary, closes the compressed file
1282 and deallocates all the (de)compression state. The return value is the zlib
1283 error number (see function gzerror below).
1284 */
1285
1286 char* gzerror(gzFile file, int* errnum);
1287 /*
1288 Returns the error message for the last error which occurred on the
1289 given compressed file. errnum is set to zlib error number. If an
1290 error occurred in the file system and not in the compression library,
1291 errnum is set to Z_ERRNO and the application may consult errno
1292 to get the exact error code.
1293 */
1294
1295 void gzclearerr(gzFile file);
1296 /*
1297 Clears the error and end-of-file flags for file. This is analogous to the
1298 clearerr() function in stdio. This is useful for continuing to read a gzip
1299 file that is being written concurrently.
1300 */
1301
1302 /* checksum functions */
1303
1304 /*
1305 These functions are not related to compression but are exported
1306 anyway because they might be useful in applications using the
1307 compression library.
1308 */
1309
1310 uLong adler32(uLong adler, Bytef* buf, uInt len);
1311 /*
1312 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1313 return the updated checksum. If buf is NULL, this function returns
1314 the required initial value for the checksum.
1315 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1316 much faster. Usage example:
1317
1318 uLong adler = adler32(0L, Z_NULL, 0);
1319
1320 while (read_buffer(buffer, length) != EOF) {
1321 adler = adler32(adler, buffer, length);
1322 }
1323 if (adler != original_adler) error();
1324 */
1325
1326 uLong adler32_combine(uLong adler1, uLong adler2, z_off_t len2);
1327 /*
1328 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1329 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1330 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1331 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
1332 */
1333
1334 uLong crc32(uLong crc, Bytef* buf, uInt len);
1335 /*
1336 Update a running CRC-32 with the bytes buf[0..len-1] and return the
1337 updated CRC-32. If buf is NULL, this function returns the required initial
1338 value for the for the crc. Pre- and post-conditioning (one's complement) is
1339 performed within this function so it shouldn't be done by the application.
1340 Usage example:
1341
1342 uLong crc = crc32(0L, Z_NULL, 0);
1343
1344 while (read_buffer(buffer, length) != EOF) {
1345 crc = crc32(crc, buffer, length);
1346 }
1347 if (crc != original_crc) error();
1348 */
1349
1350 uLong crc32_combine(uLong crc1, uLong crc2, z_off_t len2);
1351
1352 /*
1353 Combine two CRC-32 check values into one. For two sequences of bytes,
1354 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1355 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1356 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1357 len2.
1358 */
1359
1360
1361 /* various hacks, don't look :) */
1362
1363 /* deflateInit and inflateInit are macros to allow checking the zlib version
1364 * and the compiler's view of z_stream:
1365 */
1366 int deflateInit_(z_streamp strm,
1367 int level,
1368 char* ver,
1369 int stream_size);
1370 int inflateInit_(z_streamp strm,
1371 char* ver,
1372 int stream_size);
1373 int deflateInit2_(z_streamp strm,
1374 int level,
1375 int method,
1376 int windowBits,
1377 int memLevel,
1378 int strategy,
1379 char* ver,
1380 int stream_size);
1381 int inflateInit2_(z_streamp strm,
1382 int windowBits,
1383 char* ver,
1384 int stream_size);
1385 int inflateBackInit_(z_streamp strm,
1386 int windowBits,
1387 ubyte* window,
1388 char* ver,
1389 int stream_size);
1390
1391 extern (D) int deflateInit(z_streamp strm,
1392 int level)
1393 {
1394 return deflateInit_(strm,
1395 level,
1396 ZLIB_VERSION,
1397 z_stream.sizeof);
1398 }
1399
1400 extern (D) int inflateInit(z_streamp strm)
1401 {
1402 return inflateInit_(strm,
1403 ZLIB_VERSION,
1404 z_stream.sizeof);
1405 }
1406
1407 extern (D) int deflateInit2(z_streamp strm,
1408 int level,
1409 int method,
1410 int windowBits,
1411 int memLevel,
1412 int strategy)
1413 {
1414 return deflateInit2_(strm,
1415 level,
1416 method,
1417 windowBits,
1418 memLevel,
1419 strategy,
1420 ZLIB_VERSION,
1421 z_stream.sizeof);
1422 }
1423
1424 extern (D) int inflateInit2(z_streamp strm,
1425 int windowBits)
1426 {
1427 return inflateInit2_(strm,
1428 windowBits,
1429 ZLIB_VERSION,
1430 z_stream.sizeof);
1431 }
1432
1433 extern (D) int inflateBackInit(z_streamp strm,
1434 int windowBits,
1435 ubyte* window)
1436 {
1437 return inflateBackInit_(strm,
1438 windowBits,
1439 window,
1440 ZLIB_VERSION,
1441 z_stream.sizeof);
1442 }
1443
1444 char* zError(int);
1445 int inflateSyncPoint(z_streamp z);
1446 uLongf* get_crc_table();