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comparison tango/tango/io/compress/c/zlib.d @ 132:1700239cab2e trunk
[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 |
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date | Fri, 11 Jan 2008 17:57:40 +0100 |
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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(); |