1 | /* zlib.h -- interface of the 'zlib' general purpose compression library␊ |
2 | version 1.2.5, April 19th, 2010␊ |
3 | ␊ |
4 | Copyright (C) 1995-2010 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 | #ifndef ZLIB_H␊ |
32 | #define ZLIB_H␊ |
33 | ␊ |
34 | #include "zconf.h"␊ |
35 | ␊ |
36 | #ifdef __cplusplus␊ |
37 | extern "C" {␊ |
38 | #endif␊ |
39 | ␊ |
40 | #define ZLIB_VERSION "1.2.5"␊ |
41 | #define ZLIB_VERNUM 0x1250␊ |
42 | #define ZLIB_VER_MAJOR 1␊ |
43 | #define ZLIB_VER_MINOR 2␊ |
44 | #define ZLIB_VER_REVISION 5␊ |
45 | #define ZLIB_VER_SUBREVISION 0␊ |
46 | ␊ |
47 | /*␊ |
48 | The 'zlib' compression library provides in-memory compression and␊ |
49 | decompression functions, including integrity checks of the uncompressed data.␊ |
50 | This version of the library supports only one compression method (deflation)␊ |
51 | but other algorithms will be added later and will have the same stream␊ |
52 | interface.␊ |
53 | ␊ |
54 | Compression can be done in a single step if the buffers are large enough,␊ |
55 | or can be done by repeated calls of the compression function. In the latter␊ |
56 | case, the application must provide more input and/or consume the output␊ |
57 | (providing more output space) before each call.␊ |
58 | ␊ |
59 | The compressed data format used by default by the in-memory functions is␊ |
60 | the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped␊ |
61 | around a deflate stream, which is itself documented in RFC 1951.␊ |
62 | ␊ |
63 | The library also supports reading and writing files in gzip (.gz) format␊ |
64 | with an interface similar to that of stdio using the functions that start␊ |
65 | with "gz". The gzip format is different from the zlib format. gzip is a␊ |
66 | gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.␊ |
67 | ␊ |
68 | This library can optionally read and write gzip streams in memory as well.␊ |
69 | ␊ |
70 | The zlib format was designed to be compact and fast for use in memory␊ |
71 | and on communications channels. The gzip format was designed for single-␊ |
72 | file compression on file systems, has a larger header than zlib to maintain␊ |
73 | directory information, and uses a different, slower check method than zlib.␊ |
74 | ␊ |
75 | The library does not install any signal handler. The decoder checks␊ |
76 | the consistency of the compressed data, so the library should never crash␊ |
77 | even in case of corrupted input.␊ |
78 | */␊ |
79 | ␊ |
80 | typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));␊ |
81 | typedef void (*free_func) OF((voidpf opaque, voidpf address));␊ |
82 | ␊ |
83 | struct internal_state;␊ |
84 | ␊ |
85 | typedef struct z_stream_s {␊ |
86 | Bytef *next_in; /* next input byte */␊ |
87 | uInt avail_in; /* number of bytes available at next_in */␊ |
88 | uLong total_in; /* total nb of input bytes read so far */␊ |
89 | ␊ |
90 | Bytef *next_out; /* next output byte should be put there */␊ |
91 | uInt avail_out; /* remaining free space at next_out */␊ |
92 | uLong total_out; /* total nb of bytes output so far */␊ |
93 | ␊ |
94 | char *msg; /* last error message, NULL if no error */␊ |
95 | struct internal_state FAR *state; /* not visible by applications */␊ |
96 | ␊ |
97 | alloc_func zalloc; /* used to allocate the internal state */␊ |
98 | free_func zfree; /* used to free the internal state */␊ |
99 | voidpf opaque; /* private data object passed to zalloc and zfree */␊ |
100 | ␊ |
101 | int data_type; /* best guess about the data type: binary or text */␊ |
102 | uLong adler; /* adler32 value of the uncompressed data */␊ |
103 | uLong reserved; /* reserved for future use */␊ |
104 | } z_stream;␊ |
105 | ␊ |
106 | typedef z_stream FAR *z_streamp;␊ |
107 | ␊ |
108 | /*␊ |
109 | gzip header information passed to and from zlib routines. See RFC 1952␊ |
110 | for more details on the meanings of these fields.␊ |
111 | */␊ |
112 | typedef struct gz_header_s {␊ |
113 | int text; /* true if compressed data believed to be text */␊ |
114 | uLong time; /* modification time */␊ |
115 | int xflags; /* extra flags (not used when writing a gzip file) */␊ |
116 | int os; /* operating system */␊ |
117 | Bytef *extra; /* pointer to extra field or Z_NULL if none */␊ |
118 | uInt extra_len; /* extra field length (valid if extra != Z_NULL) */␊ |
119 | uInt extra_max; /* space at extra (only when reading header) */␊ |
120 | Bytef *name; /* pointer to zero-terminated file name or Z_NULL */␊ |
121 | uInt name_max; /* space at name (only when reading header) */␊ |
122 | Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */␊ |
123 | uInt comm_max; /* space at comment (only when reading header) */␊ |
124 | int hcrc; /* true if there was or will be a header crc */␊ |
125 | int done; /* true when done reading gzip header (not used␊ |
126 | when writing a gzip file) */␊ |
127 | } gz_header;␊ |
128 | ␊ |
129 | typedef gz_header FAR *gz_headerp;␊ |
130 | ␊ |
131 | /*␊ |
132 | The application must update next_in and avail_in when avail_in has dropped␊ |
133 | to zero. It must update next_out and avail_out when avail_out has dropped␊ |
134 | to zero. The application must initialize zalloc, zfree and opaque before␊ |
135 | calling the init function. All other fields are set by the compression␊ |
136 | library and must not be updated by the application.␊ |
137 | ␊ |
138 | The opaque value provided by the application will be passed as the first␊ |
139 | parameter for calls of zalloc and zfree. This can be useful for custom␊ |
140 | memory management. The compression library attaches no meaning to the␊ |
141 | opaque value.␊ |
142 | ␊ |
143 | zalloc must return Z_NULL if there is not enough memory for the object.␊ |
144 | If zlib is used in a multi-threaded application, zalloc and zfree must be␊ |
145 | thread safe.␊ |
146 | ␊ |
147 | On 16-bit systems, the functions zalloc and zfree must be able to allocate␊ |
148 | exactly 65536 bytes, but will not be required to allocate more than this if␊ |
149 | the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers␊ |
150 | returned by zalloc for objects of exactly 65536 bytes *must* have their␊ |
151 | offset normalized to zero. The default allocation function provided by this␊ |
152 | library ensures this (see zutil.c). To reduce memory requirements and avoid␊ |
153 | any allocation of 64K objects, at the expense of compression ratio, compile␊ |
154 | the library with -DMAX_WBITS=14 (see zconf.h).␊ |
155 | ␊ |
156 | The fields total_in and total_out can be used for statistics or progress␊ |
157 | reports. After compression, total_in holds the total size of the␊ |
158 | uncompressed data and may be saved for use in the decompressor (particularly␊ |
159 | if the decompressor wants to decompress everything in a single step).␊ |
160 | */␊ |
161 | ␊ |
162 | /* constants */␊ |
163 | ␊ |
164 | #define Z_NO_FLUSH 0␊ |
165 | #define Z_PARTIAL_FLUSH 1␊ |
166 | #define Z_SYNC_FLUSH 2␊ |
167 | #define Z_FULL_FLUSH 3␊ |
168 | #define Z_FINISH 4␊ |
169 | #define Z_BLOCK 5␊ |
170 | #define Z_TREES 6␊ |
171 | /* Allowed flush values; see deflate() and inflate() below for details */␊ |
172 | ␊ |
173 | #define Z_OK 0␊ |
174 | #define Z_STREAM_END 1␊ |
175 | #define Z_NEED_DICT 2␊ |
176 | #define Z_ERRNO (-1)␊ |
177 | #define Z_STREAM_ERROR (-2)␊ |
178 | #define Z_DATA_ERROR (-3)␊ |
179 | #define Z_MEM_ERROR (-4)␊ |
180 | #define Z_BUF_ERROR (-5)␊ |
181 | #define Z_VERSION_ERROR (-6)␊ |
182 | /* Return codes for the compression/decompression functions. Negative values␊ |
183 | * are errors, positive values are used for special but normal events.␊ |
184 | */␊ |
185 | ␊ |
186 | #define Z_NO_COMPRESSION 0␊ |
187 | #define Z_BEST_SPEED 1␊ |
188 | #define Z_BEST_COMPRESSION 9␊ |
189 | #define Z_DEFAULT_COMPRESSION (-1)␊ |
190 | /* compression levels */␊ |
191 | ␊ |
192 | #define Z_FILTERED 1␊ |
193 | #define Z_HUFFMAN_ONLY 2␊ |
194 | #define Z_RLE 3␊ |
195 | #define Z_FIXED 4␊ |
196 | #define Z_DEFAULT_STRATEGY 0␊ |
197 | /* compression strategy; see deflateInit2() below for details */␊ |
198 | ␊ |
199 | #define Z_BINARY 0␊ |
200 | #define Z_TEXT 1␊ |
201 | #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */␊ |
202 | #define Z_UNKNOWN 2␊ |
203 | /* Possible values of the data_type field (though see inflate()) */␊ |
204 | ␊ |
205 | #define Z_DEFLATED 8␊ |
206 | /* The deflate compression method (the only one supported in this version) */␊ |
207 | ␊ |
208 | #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */␊ |
209 | ␊ |
210 | #define zlib_version zlibVersion()␊ |
211 | /* for compatibility with versions < 1.0.2 */␊ |
212 | ␊ |
213 | ␊ |
214 | /* basic functions */␊ |
215 | ␊ |
216 | ZEXTERN const char * ZEXPORT zlibVersion OF((void));␊ |
217 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency.␊ |
218 | If the first character differs, the library code actually used is not␊ |
219 | compatible with the zlib.h header file used by the application. This check␊ |
220 | is automatically made by deflateInit and inflateInit.␊ |
221 | */␊ |
222 | ␊ |
223 | /*␊ |
224 | ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));␊ |
225 | ␊ |
226 | Initializes the internal stream state for compression. The fields␊ |
227 | zalloc, zfree and opaque must be initialized before by the caller. If␊ |
228 | zalloc and zfree are set to Z_NULL, deflateInit updates them to use default␊ |
229 | allocation functions.␊ |
230 | ␊ |
231 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:␊ |
232 | 1 gives best speed, 9 gives best compression, 0 gives no compression at all␊ |
233 | (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION␊ |
234 | requests a default compromise between speed and compression (currently␊ |
235 | equivalent to level 6).␊ |
236 | ␊ |
237 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
238 | memory, Z_STREAM_ERROR if level is not a valid compression level, or␊ |
239 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible␊ |
240 | with the version assumed by the caller (ZLIB_VERSION). msg is set to null␊ |
241 | if there is no error message. deflateInit does not perform any compression:␊ |
242 | this will be done by deflate().␊ |
243 | */␊ |
244 | ␊ |
245 | ␊ |
246 | ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));␊ |
247 | /*␊ |
248 | deflate compresses as much data as possible, and stops when the input␊ |
249 | buffer becomes empty or the output buffer becomes full. It may introduce␊ |
250 | some output latency (reading input without producing any output) except when␊ |
251 | forced to flush.␊ |
252 | ␊ |
253 | The detailed semantics are as follows. deflate performs one or both of the␊ |
254 | following actions:␊ |
255 | ␊ |
256 | - Compress more input starting at next_in and update next_in and avail_in␊ |
257 | accordingly. If not all input can be processed (because there is not␊ |
258 | enough room in the output buffer), next_in and avail_in are updated and␊ |
259 | processing will resume at this point for the next call of deflate().␊ |
260 | ␊ |
261 | - Provide more output starting at next_out and update next_out and avail_out␊ |
262 | accordingly. This action is forced if the parameter flush is non zero.␊ |
263 | Forcing flush frequently degrades the compression ratio, so this parameter␊ |
264 | should be set only when necessary (in interactive applications). Some␊ |
265 | output may be provided even if flush is not set.␊ |
266 | ␊ |
267 | Before the call of deflate(), the application should ensure that at least␊ |
268 | one of the actions is possible, by providing more input and/or consuming more␊ |
269 | output, and updating avail_in or avail_out accordingly; avail_out should␊ |
270 | never be zero before the call. The application can consume the compressed␊ |
271 | output when it wants, for example when the output buffer is full (avail_out␊ |
272 | == 0), or after each call of deflate(). If deflate returns Z_OK and with␊ |
273 | zero avail_out, it must be called again after making room in the output␊ |
274 | buffer because there might be more output pending.␊ |
275 | ␊ |
276 | Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to␊ |
277 | decide how much data to accumulate before producing output, in order to␊ |
278 | maximize compression.␊ |
279 | ␊ |
280 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is␊ |
281 | flushed to the output buffer and the output is aligned on a byte boundary, so␊ |
282 | that the decompressor can get all input data available so far. (In␊ |
283 | particular avail_in is zero after the call if enough output space has been␊ |
284 | provided before the call.) Flushing may degrade compression for some␊ |
285 | compression algorithms and so it should be used only when necessary. This␊ |
286 | completes the current deflate block and follows it with an empty stored block␊ |
287 | that is three bits plus filler bits to the next byte, followed by four bytes␊ |
288 | (00 00 ff ff).␊ |
289 | ␊ |
290 | If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the␊ |
291 | output buffer, but the output is not aligned to a byte boundary. All of the␊ |
292 | input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.␊ |
293 | This completes the current deflate block and follows it with an empty fixed␊ |
294 | codes block that is 10 bits long. This assures that enough bytes are output␊ |
295 | in order for the decompressor to finish the block before the empty fixed code␊ |
296 | block.␊ |
297 | ␊ |
298 | If flush is set to Z_BLOCK, a deflate block is completed and emitted, as␊ |
299 | for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to␊ |
300 | seven bits of the current block are held to be written as the next byte after␊ |
301 | the next deflate block is completed. In this case, the decompressor may not␊ |
302 | be provided enough bits at this point in order to complete decompression of␊ |
303 | the data provided so far to the compressor. It may need to wait for the next␊ |
304 | block to be emitted. This is for advanced applications that need to control␊ |
305 | the emission of deflate blocks.␊ |
306 | ␊ |
307 | If flush is set to Z_FULL_FLUSH, all output is flushed as with␊ |
308 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can␊ |
309 | restart from this point if previous compressed data has been damaged or if␊ |
310 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade␊ |
311 | compression.␊ |
312 | ␊ |
313 | If deflate returns with avail_out == 0, this function must be called again␊ |
314 | with the same value of the flush parameter and more output space (updated␊ |
315 | avail_out), until the flush is complete (deflate returns with non-zero␊ |
316 | avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that␊ |
317 | avail_out is greater than six to avoid repeated flush markers due to␊ |
318 | avail_out == 0 on return.␊ |
319 | ␊ |
320 | If the parameter flush is set to Z_FINISH, pending input is processed,␊ |
321 | pending output is flushed and deflate returns with Z_STREAM_END if there was␊ |
322 | enough output space; if deflate returns with Z_OK, this function must be␊ |
323 | called again with Z_FINISH and more output space (updated avail_out) but no␊ |
324 | more input data, until it returns with Z_STREAM_END or an error. After␊ |
325 | deflate has returned Z_STREAM_END, the only possible operations on the stream␊ |
326 | are deflateReset or deflateEnd.␊ |
327 | ␊ |
328 | Z_FINISH can be used immediately after deflateInit if all the compression␊ |
329 | is to be done in a single step. In this case, avail_out must be at least the␊ |
330 | value returned by deflateBound (see below). If deflate does not return␊ |
331 | Z_STREAM_END, then it must be called again as described above.␊ |
332 | ␊ |
333 | deflate() sets strm->adler to the adler32 checksum of all input read␊ |
334 | so far (that is, total_in bytes).␊ |
335 | ␊ |
336 | deflate() may update strm->data_type if it can make a good guess about␊ |
337 | the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered␊ |
338 | binary. This field is only for information purposes and does not affect the␊ |
339 | compression algorithm in any manner.␊ |
340 | ␊ |
341 | deflate() returns Z_OK if some progress has been made (more input␊ |
342 | processed or more output produced), Z_STREAM_END if all input has been␊ |
343 | consumed and all output has been produced (only when flush is set to␊ |
344 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example␊ |
345 | if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible␊ |
346 | (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not␊ |
347 | fatal, and deflate() can be called again with more input and more output␊ |
348 | space to continue compressing.␊ |
349 | */␊ |
350 | ␊ |
351 | ␊ |
352 | ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));␊ |
353 | /*␊ |
354 | All dynamically allocated data structures for this stream are freed.␊ |
355 | This function discards any unprocessed input and does not flush any pending␊ |
356 | output.␊ |
357 | ␊ |
358 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the␊ |
359 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed␊ |
360 | prematurely (some input or output was discarded). In the error case, msg␊ |
361 | may be set but then points to a static string (which must not be␊ |
362 | deallocated).␊ |
363 | */␊ |
364 | ␊ |
365 | ␊ |
366 | /*␊ |
367 | ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));␊ |
368 | ␊ |
369 | Initializes the internal stream state for decompression. The fields␊ |
370 | next_in, avail_in, zalloc, zfree and opaque must be initialized before by␊ |
371 | the caller. If next_in is not Z_NULL and avail_in is large enough (the␊ |
372 | exact value depends on the compression method), inflateInit determines the␊ |
373 | compression method from the zlib header and allocates all data structures␊ |
374 | accordingly; otherwise the allocation will be deferred to the first call of␊ |
375 | inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to␊ |
376 | use default allocation functions.␊ |
377 | ␊ |
378 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
379 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the␊ |
380 | version assumed by the caller, or Z_STREAM_ERROR if the parameters are␊ |
381 | invalid, such as a null pointer to the structure. msg is set to null if␊ |
382 | there is no error message. inflateInit does not perform any decompression␊ |
383 | apart from possibly reading the zlib header if present: actual decompression␊ |
384 | will be done by inflate(). (So next_in and avail_in may be modified, but␊ |
385 | next_out and avail_out are unused and unchanged.) The current implementation␊ |
386 | of inflateInit() does not process any header information -- that is deferred␊ |
387 | until inflate() is called.␊ |
388 | */␊ |
389 | ␊ |
390 | ␊ |
391 | ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));␊ |
392 | /*␊ |
393 | inflate decompresses as much data as possible, and stops when the input␊ |
394 | buffer becomes empty or the output buffer becomes full. It may introduce␊ |
395 | some output latency (reading input without producing any output) except when␊ |
396 | forced to flush.␊ |
397 | ␊ |
398 | The detailed semantics are as follows. inflate performs one or both of the␊ |
399 | following actions:␊ |
400 | ␊ |
401 | - Decompress more input starting at next_in and update next_in and avail_in␊ |
402 | accordingly. If not all input can be processed (because there is not␊ |
403 | enough room in the output buffer), next_in is updated and processing will␊ |
404 | resume at this point for the next call of inflate().␊ |
405 | ␊ |
406 | - Provide more output starting at next_out and update next_out and avail_out␊ |
407 | accordingly. inflate() provides as much output as possible, until there is␊ |
408 | no more input data or no more space in the output buffer (see below about␊ |
409 | the flush parameter).␊ |
410 | ␊ |
411 | Before the call of inflate(), the application should ensure that at least␊ |
412 | one of the actions is possible, by providing more input and/or consuming more␊ |
413 | output, and updating the next_* and avail_* values accordingly. The␊ |
414 | application can consume the uncompressed output when it wants, for example␊ |
415 | when the output buffer is full (avail_out == 0), or after each call of␊ |
416 | inflate(). If inflate returns Z_OK and with zero avail_out, it must be␊ |
417 | called again after making room in the output buffer because there might be␊ |
418 | more output pending.␊ |
419 | ␊ |
420 | The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,␊ |
421 | Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much␊ |
422 | output as possible to the output buffer. Z_BLOCK requests that inflate()␊ |
423 | stop if and when it gets to the next deflate block boundary. When decoding␊ |
424 | the zlib or gzip format, this will cause inflate() to return immediately␊ |
425 | after the header and before the first block. When doing a raw inflate,␊ |
426 | inflate() will go ahead and process the first block, and will return when it␊ |
427 | gets to the end of that block, or when it runs out of data.␊ |
428 | ␊ |
429 | The Z_BLOCK option assists in appending to or combining deflate streams.␊ |
430 | Also to assist in this, on return inflate() will set strm->data_type to the␊ |
431 | number of unused bits in the last byte taken from strm->next_in, plus 64 if␊ |
432 | inflate() is currently decoding the last block in the deflate stream, plus␊ |
433 | 128 if inflate() returned immediately after decoding an end-of-block code or␊ |
434 | decoding the complete header up to just before the first byte of the deflate␊ |
435 | stream. The end-of-block will not be indicated until all of the uncompressed␊ |
436 | data from that block has been written to strm->next_out. The number of␊ |
437 | unused bits may in general be greater than seven, except when bit 7 of␊ |
438 | data_type is set, in which case the number of unused bits will be less than␊ |
439 | eight. data_type is set as noted here every time inflate() returns for all␊ |
440 | flush options, and so can be used to determine the amount of currently␊ |
441 | consumed input in bits.␊ |
442 | ␊ |
443 | The Z_TREES option behaves as Z_BLOCK does, but it also returns when the␊ |
444 | end of each deflate block header is reached, before any actual data in that␊ |
445 | block is decoded. This allows the caller to determine the length of the␊ |
446 | deflate block header for later use in random access within a deflate block.␊ |
447 | 256 is added to the value of strm->data_type when inflate() returns␊ |
448 | immediately after reaching the end of the deflate block header.␊ |
449 | ␊ |
450 | inflate() should normally be called until it returns Z_STREAM_END or an␊ |
451 | error. However if all decompression is to be performed in a single step (a␊ |
452 | single call of inflate), the parameter flush should be set to Z_FINISH. In␊ |
453 | this case all pending input is processed and all pending output is flushed;␊ |
454 | avail_out must be large enough to hold all the uncompressed data. (The size␊ |
455 | of the uncompressed data may have been saved by the compressor for this␊ |
456 | purpose.) The next operation on this stream must be inflateEnd to deallocate␊ |
457 | the decompression state. The use of Z_FINISH is never required, but can be␊ |
458 | used to inform inflate that a faster approach may be used for the single␊ |
459 | inflate() call.␊ |
460 | ␊ |
461 | In this implementation, inflate() always flushes as much output as␊ |
462 | possible to the output buffer, and always uses the faster approach on the␊ |
463 | first call. So the only effect of the flush parameter in this implementation␊ |
464 | is on the return value of inflate(), as noted below, or when it returns early␊ |
465 | because Z_BLOCK or Z_TREES is used.␊ |
466 | ␊ |
467 | If a preset dictionary is needed after this call (see inflateSetDictionary␊ |
468 | below), inflate sets strm->adler to the adler32 checksum of the dictionary␊ |
469 | chosen by the compressor and returns Z_NEED_DICT; otherwise it sets␊ |
470 | strm->adler to the adler32 checksum of all output produced so far (that is,␊ |
471 | total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described␊ |
472 | below. At the end of the stream, inflate() checks that its computed adler32␊ |
473 | checksum is equal to that saved by the compressor and returns Z_STREAM_END␊ |
474 | only if the checksum is correct.␊ |
475 | ␊ |
476 | inflate() can decompress and check either zlib-wrapped or gzip-wrapped␊ |
477 | deflate data. The header type is detected automatically, if requested when␊ |
478 | initializing with inflateInit2(). Any information contained in the gzip␊ |
479 | header is not retained, so applications that need that information should␊ |
480 | instead use raw inflate, see inflateInit2() below, or inflateBack() and␊ |
481 | perform their own processing of the gzip header and trailer.␊ |
482 | ␊ |
483 | inflate() returns Z_OK if some progress has been made (more input processed␊ |
484 | or more output produced), Z_STREAM_END if the end of the compressed data has␊ |
485 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a␊ |
486 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was␊ |
487 | corrupted (input stream not conforming to the zlib format or incorrect check␊ |
488 | value), Z_STREAM_ERROR if the stream structure was inconsistent (for example␊ |
489 | next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,␊ |
490 | Z_BUF_ERROR if no progress is possible or if there was not enough room in the␊ |
491 | output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and␊ |
492 | inflate() can be called again with more input and more output space to␊ |
493 | continue decompressing. If Z_DATA_ERROR is returned, the application may␊ |
494 | then call inflateSync() to look for a good compression block if a partial␊ |
495 | recovery of the data is desired.␊ |
496 | */␊ |
497 | ␊ |
498 | ␊ |
499 | ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));␊ |
500 | /*␊ |
501 | All dynamically allocated data structures for this stream are freed.␊ |
502 | This function discards any unprocessed input and does not flush any pending␊ |
503 | output.␊ |
504 | ␊ |
505 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state␊ |
506 | was inconsistent. In the error case, msg may be set but then points to a␊ |
507 | static string (which must not be deallocated).␊ |
508 | */␊ |
509 | ␊ |
510 | ␊ |
511 | /* Advanced functions */␊ |
512 | ␊ |
513 | /*␊ |
514 | The following functions are needed only in some special applications.␊ |
515 | */␊ |
516 | ␊ |
517 | /*␊ |
518 | ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,␊ |
519 | int level,␊ |
520 | int method,␊ |
521 | int windowBits,␊ |
522 | int memLevel,␊ |
523 | int strategy));␊ |
524 | ␊ |
525 | This is another version of deflateInit with more compression options. The␊ |
526 | fields next_in, zalloc, zfree and opaque must be initialized before by the␊ |
527 | caller.␊ |
528 | ␊ |
529 | The method parameter is the compression method. It must be Z_DEFLATED in␊ |
530 | this version of the library.␊ |
531 | ␊ |
532 | The windowBits parameter is the base two logarithm of the window size␊ |
533 | (the size of the history buffer). It should be in the range 8..15 for this␊ |
534 | version of the library. Larger values of this parameter result in better␊ |
535 | compression at the expense of memory usage. The default value is 15 if␊ |
536 | deflateInit is used instead.␊ |
537 | ␊ |
538 | windowBits can also be -8..-15 for raw deflate. In this case, -windowBits␊ |
539 | determines the window size. deflate() will then generate raw deflate data␊ |
540 | with no zlib header or trailer, and will not compute an adler32 check value.␊ |
541 | ␊ |
542 | windowBits can also be greater than 15 for optional gzip encoding. Add␊ |
543 | 16 to windowBits to write a simple gzip header and trailer around the␊ |
544 | compressed data instead of a zlib wrapper. The gzip header will have no␊ |
545 | file name, no extra data, no comment, no modification time (set to zero), no␊ |
546 | header crc, and the operating system will be set to 255 (unknown). If a␊ |
547 | gzip stream is being written, strm->adler is a crc32 instead of an adler32.␊ |
548 | ␊ |
549 | The memLevel parameter specifies how much memory should be allocated␊ |
550 | for the internal compression state. memLevel=1 uses minimum memory but is␊ |
551 | slow and reduces compression ratio; memLevel=9 uses maximum memory for␊ |
552 | optimal speed. The default value is 8. See zconf.h for total memory usage␊ |
553 | as a function of windowBits and memLevel.␊ |
554 | ␊ |
555 | The strategy parameter is used to tune the compression algorithm. Use the␊ |
556 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a␊ |
557 | filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no␊ |
558 | string match), or Z_RLE to limit match distances to one (run-length␊ |
559 | encoding). Filtered data consists mostly of small values with a somewhat␊ |
560 | random distribution. In this case, the compression algorithm is tuned to␊ |
561 | compress them better. The effect of Z_FILTERED is to force more Huffman␊ |
562 | coding and less string matching; it is somewhat intermediate between␊ |
563 | Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as␊ |
564 | fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The␊ |
565 | strategy parameter only affects the compression ratio but not the␊ |
566 | correctness of the compressed output even if it is not set appropriately.␊ |
567 | Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler␊ |
568 | decoder for special applications.␊ |
569 | ␊ |
570 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
571 | memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid␊ |
572 | method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is␊ |
573 | incompatible with the version assumed by the caller (ZLIB_VERSION). msg is␊ |
574 | set to null if there is no error message. deflateInit2 does not perform any␊ |
575 | compression: this will be done by deflate().␊ |
576 | */␊ |
577 | ␊ |
578 | ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,␊ |
579 | const Bytef *dictionary,␊ |
580 | uInt dictLength));␊ |
581 | /*␊ |
582 | Initializes the compression dictionary from the given byte sequence␊ |
583 | without producing any compressed output. This function must be called␊ |
584 | immediately after deflateInit, deflateInit2 or deflateReset, before any call␊ |
585 | of deflate. The compressor and decompressor must use exactly the same␊ |
586 | dictionary (see inflateSetDictionary).␊ |
587 | ␊ |
588 | The dictionary should consist of strings (byte sequences) that are likely␊ |
589 | to be encountered later in the data to be compressed, with the most commonly␊ |
590 | used strings preferably put towards the end of the dictionary. Using a␊ |
591 | dictionary is most useful when the data to be compressed is short and can be␊ |
592 | predicted with good accuracy; the data can then be compressed better than␊ |
593 | with the default empty dictionary.␊ |
594 | ␊ |
595 | Depending on the size of the compression data structures selected by␊ |
596 | deflateInit or deflateInit2, a part of the dictionary may in effect be␊ |
597 | discarded, for example if the dictionary is larger than the window size␊ |
598 | provided in deflateInit or deflateInit2. Thus the strings most likely to be␊ |
599 | useful should be put at the end of the dictionary, not at the front. In␊ |
600 | addition, the current implementation of deflate will use at most the window␊ |
601 | size minus 262 bytes of the provided dictionary.␊ |
602 | ␊ |
603 | Upon return of this function, strm->adler is set to the adler32 value␊ |
604 | of the dictionary; the decompressor may later use this value to determine␊ |
605 | which dictionary has been used by the compressor. (The adler32 value␊ |
606 | applies to the whole dictionary even if only a subset of the dictionary is␊ |
607 | actually used by the compressor.) If a raw deflate was requested, then the␊ |
608 | adler32 value is not computed and strm->adler is not set.␊ |
609 | ␊ |
610 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a␊ |
611 | parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is␊ |
612 | inconsistent (for example if deflate has already been called for this stream␊ |
613 | or if the compression method is bsort). deflateSetDictionary does not␊ |
614 | perform any compression: this will be done by deflate().␊ |
615 | */␊ |
616 | ␊ |
617 | ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,␊ |
618 | z_streamp source));␊ |
619 | /*␊ |
620 | Sets the destination stream as a complete copy of the source stream.␊ |
621 | ␊ |
622 | This function can be useful when several compression strategies will be␊ |
623 | tried, for example when there are several ways of pre-processing the input␊ |
624 | data with a filter. The streams that will be discarded should then be freed␊ |
625 | by calling deflateEnd. Note that deflateCopy duplicates the internal␊ |
626 | compression state which can be quite large, so this strategy is slow and can␊ |
627 | consume lots of memory.␊ |
628 | ␊ |
629 | deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not␊ |
630 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent␊ |
631 | (such as zalloc being Z_NULL). msg is left unchanged in both source and␊ |
632 | destination.␊ |
633 | */␊ |
634 | ␊ |
635 | ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));␊ |
636 | /*␊ |
637 | This function is equivalent to deflateEnd followed by deflateInit,␊ |
638 | but does not free and reallocate all the internal compression state. The␊ |
639 | stream will keep the same compression level and any other attributes that␊ |
640 | may have been set by deflateInit2.␊ |
641 | ␊ |
642 | deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
643 | stream state was inconsistent (such as zalloc or state being Z_NULL).␊ |
644 | */␊ |
645 | ␊ |
646 | ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,␊ |
647 | int level,␊ |
648 | int strategy));␊ |
649 | /*␊ |
650 | Dynamically update the compression level and compression strategy. The␊ |
651 | interpretation of level and strategy is as in deflateInit2. This can be␊ |
652 | used to switch between compression and straight copy of the input data, or␊ |
653 | to switch to a different kind of input data requiring a different strategy.␊ |
654 | If the compression level is changed, the input available so far is␊ |
655 | compressed with the old level (and may be flushed); the new level will take␊ |
656 | effect only at the next call of deflate().␊ |
657 | ␊ |
658 | Before the call of deflateParams, the stream state must be set as for␊ |
659 | a call of deflate(), since the currently available input may have to be␊ |
660 | compressed and flushed. In particular, strm->avail_out must be non-zero.␊ |
661 | ␊ |
662 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source␊ |
663 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if␊ |
664 | strm->avail_out was zero.␊ |
665 | */␊ |
666 | ␊ |
667 | ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,␊ |
668 | int good_length,␊ |
669 | int max_lazy,␊ |
670 | int nice_length,␊ |
671 | int max_chain));␊ |
672 | /*␊ |
673 | Fine tune deflate's internal compression parameters. This should only be␊ |
674 | used by someone who understands the algorithm used by zlib's deflate for␊ |
675 | searching for the best matching string, and even then only by the most␊ |
676 | fanatic optimizer trying to squeeze out the last compressed bit for their␊ |
677 | specific input data. Read the deflate.c source code for the meaning of the␊ |
678 | max_lazy, good_length, nice_length, and max_chain parameters.␊ |
679 | ␊ |
680 | deflateTune() can be called after deflateInit() or deflateInit2(), and␊ |
681 | returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.␊ |
682 | */␊ |
683 | ␊ |
684 | ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,␊ |
685 | uLong sourceLen));␊ |
686 | /*␊ |
687 | deflateBound() returns an upper bound on the compressed size after␊ |
688 | deflation of sourceLen bytes. It must be called after deflateInit() or␊ |
689 | deflateInit2(), and after deflateSetHeader(), if used. This would be used␊ |
690 | to allocate an output buffer for deflation in a single pass, and so would be␊ |
691 | called before deflate().␊ |
692 | */␊ |
693 | ␊ |
694 | ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,␊ |
695 | int bits,␊ |
696 | int value));␊ |
697 | /*␊ |
698 | deflatePrime() inserts bits in the deflate output stream. The intent␊ |
699 | is that this function is used to start off the deflate output with the bits␊ |
700 | leftover from a previous deflate stream when appending to it. As such, this␊ |
701 | function can only be used for raw deflate, and must be used before the first␊ |
702 | deflate() call after a deflateInit2() or deflateReset(). bits must be less␊ |
703 | than or equal to 16, and that many of the least significant bits of value␊ |
704 | will be inserted in the output.␊ |
705 | ␊ |
706 | deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
707 | stream state was inconsistent.␊ |
708 | */␊ |
709 | ␊ |
710 | ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,␊ |
711 | gz_headerp head));␊ |
712 | /*␊ |
713 | deflateSetHeader() provides gzip header information for when a gzip␊ |
714 | stream is requested by deflateInit2(). deflateSetHeader() may be called␊ |
715 | after deflateInit2() or deflateReset() and before the first call of␊ |
716 | deflate(). The text, time, os, extra field, name, and comment information␊ |
717 | in the provided gz_header structure are written to the gzip header (xflag is␊ |
718 | ignored -- the extra flags are set according to the compression level). The␊ |
719 | caller must assure that, if not Z_NULL, name and comment are terminated with␊ |
720 | a zero byte, and that if extra is not Z_NULL, that extra_len bytes are␊ |
721 | available there. If hcrc is true, a gzip header crc is included. Note that␊ |
722 | the current versions of the command-line version of gzip (up through version␊ |
723 | 1.3.x) do not support header crc's, and will report that it is a "multi-part␊ |
724 | gzip file" and give up.␊ |
725 | ␊ |
726 | If deflateSetHeader is not used, the default gzip header has text false,␊ |
727 | the time set to zero, and os set to 255, with no extra, name, or comment␊ |
728 | fields. The gzip header is returned to the default state by deflateReset().␊ |
729 | ␊ |
730 | deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
731 | stream state was inconsistent.␊ |
732 | */␊ |
733 | ␊ |
734 | /*␊ |
735 | ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,␊ |
736 | int windowBits));␊ |
737 | ␊ |
738 | This is another version of inflateInit with an extra parameter. The␊ |
739 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized␊ |
740 | before by the caller.␊ |
741 | ␊ |
742 | The windowBits parameter is the base two logarithm of the maximum window␊ |
743 | size (the size of the history buffer). It should be in the range 8..15 for␊ |
744 | this version of the library. The default value is 15 if inflateInit is used␊ |
745 | instead. windowBits must be greater than or equal to the windowBits value␊ |
746 | provided to deflateInit2() while compressing, or it must be equal to 15 if␊ |
747 | deflateInit2() was not used. If a compressed stream with a larger window␊ |
748 | size is given as input, inflate() will return with the error code␊ |
749 | Z_DATA_ERROR instead of trying to allocate a larger window.␊ |
750 | ␊ |
751 | windowBits can also be zero to request that inflate use the window size in␊ |
752 | the zlib header of the compressed stream.␊ |
753 | ␊ |
754 | windowBits can also be -8..-15 for raw inflate. In this case, -windowBits␊ |
755 | determines the window size. inflate() will then process raw deflate data,␊ |
756 | not looking for a zlib or gzip header, not generating a check value, and not␊ |
757 | looking for any check values for comparison at the end of the stream. This␊ |
758 | is for use with other formats that use the deflate compressed data format␊ |
759 | such as zip. Those formats provide their own check values. If a custom␊ |
760 | format is developed using the raw deflate format for compressed data, it is␊ |
761 | recommended that a check value such as an adler32 or a crc32 be applied to␊ |
762 | the uncompressed data as is done in the zlib, gzip, and zip formats. For␊ |
763 | most applications, the zlib format should be used as is. Note that comments␊ |
764 | above on the use in deflateInit2() applies to the magnitude of windowBits.␊ |
765 | ␊ |
766 | windowBits can also be greater than 15 for optional gzip decoding. Add␊ |
767 | 32 to windowBits to enable zlib and gzip decoding with automatic header␊ |
768 | detection, or add 16 to decode only the gzip format (the zlib format will␊ |
769 | return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a␊ |
770 | crc32 instead of an adler32.␊ |
771 | ␊ |
772 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
773 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the␊ |
774 | version assumed by the caller, or Z_STREAM_ERROR if the parameters are␊ |
775 | invalid, such as a null pointer to the structure. msg is set to null if␊ |
776 | there is no error message. inflateInit2 does not perform any decompression␊ |
777 | apart from possibly reading the zlib header if present: actual decompression␊ |
778 | will be done by inflate(). (So next_in and avail_in may be modified, but␊ |
779 | next_out and avail_out are unused and unchanged.) The current implementation␊ |
780 | of inflateInit2() does not process any header information -- that is␊ |
781 | deferred until inflate() is called.␊ |
782 | */␊ |
783 | ␊ |
784 | ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,␊ |
785 | const Bytef *dictionary,␊ |
786 | uInt dictLength));␊ |
787 | /*␊ |
788 | Initializes the decompression dictionary from the given uncompressed byte␊ |
789 | sequence. This function must be called immediately after a call of inflate,␊ |
790 | if that call returned Z_NEED_DICT. The dictionary chosen by the compressor␊ |
791 | can be determined from the adler32 value returned by that call of inflate.␊ |
792 | The compressor and decompressor must use exactly the same dictionary (see␊ |
793 | deflateSetDictionary). For raw inflate, this function can be called␊ |
794 | immediately after inflateInit2() or inflateReset() and before any call of␊ |
795 | inflate() to set the dictionary. The application must insure that the␊ |
796 | dictionary that was used for compression is provided.␊ |
797 | ␊ |
798 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a␊ |
799 | parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is␊ |
800 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the␊ |
801 | expected one (incorrect adler32 value). inflateSetDictionary does not␊ |
802 | perform any decompression: this will be done by subsequent calls of␊ |
803 | inflate().␊ |
804 | */␊ |
805 | ␊ |
806 | ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));␊ |
807 | /*␊ |
808 | Skips invalid compressed data until a full flush point (see above the␊ |
809 | description of deflate with Z_FULL_FLUSH) can be found, or until all␊ |
810 | available input is skipped. No output is provided.␊ |
811 | ␊ |
812 | inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR␊ |
813 | if no more input was provided, Z_DATA_ERROR if no flush point has been␊ |
814 | found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the␊ |
815 | success case, the application may save the current current value of total_in␊ |
816 | which indicates where valid compressed data was found. In the error case,␊ |
817 | the application may repeatedly call inflateSync, providing more input each␊ |
818 | time, until success or end of the input data.␊ |
819 | */␊ |
820 | ␊ |
821 | ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,␊ |
822 | z_streamp source));␊ |
823 | /*␊ |
824 | Sets the destination stream as a complete copy of the source stream.␊ |
825 | ␊ |
826 | This function can be useful when randomly accessing a large stream. The␊ |
827 | first pass through the stream can periodically record the inflate state,␊ |
828 | allowing restarting inflate at those points when randomly accessing the␊ |
829 | stream.␊ |
830 | ␊ |
831 | inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not␊ |
832 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent␊ |
833 | (such as zalloc being Z_NULL). msg is left unchanged in both source and␊ |
834 | destination.␊ |
835 | */␊ |
836 | ␊ |
837 | ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));␊ |
838 | /*␊ |
839 | This function is equivalent to inflateEnd followed by inflateInit,␊ |
840 | but does not free and reallocate all the internal decompression state. The␊ |
841 | stream will keep attributes that may have been set by inflateInit2.␊ |
842 | ␊ |
843 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
844 | stream state was inconsistent (such as zalloc or state being Z_NULL).␊ |
845 | */␊ |
846 | ␊ |
847 | ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,␊ |
848 | int windowBits));␊ |
849 | /*␊ |
850 | This function is the same as inflateReset, but it also permits changing␊ |
851 | the wrap and window size requests. The windowBits parameter is interpreted␊ |
852 | the same as it is for inflateInit2.␊ |
853 | ␊ |
854 | inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
855 | stream state was inconsistent (such as zalloc or state being Z_NULL), or if␊ |
856 | the windowBits parameter is invalid.␊ |
857 | */␊ |
858 | ␊ |
859 | ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,␊ |
860 | int bits,␊ |
861 | int value));␊ |
862 | /*␊ |
863 | This function inserts bits in the inflate input stream. The intent is␊ |
864 | that this function is used to start inflating at a bit position in the␊ |
865 | middle of a byte. The provided bits will be used before any bytes are used␊ |
866 | from next_in. This function should only be used with raw inflate, and␊ |
867 | should be used before the first inflate() call after inflateInit2() or␊ |
868 | inflateReset(). bits must be less than or equal to 16, and that many of the␊ |
869 | least significant bits of value will be inserted in the input.␊ |
870 | ␊ |
871 | If bits is negative, then the input stream bit buffer is emptied. Then␊ |
872 | inflatePrime() can be called again to put bits in the buffer. This is used␊ |
873 | to clear out bits leftover after feeding inflate a block description prior␊ |
874 | to feeding inflate codes.␊ |
875 | ␊ |
876 | inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
877 | stream state was inconsistent.␊ |
878 | */␊ |
879 | ␊ |
880 | ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));␊ |
881 | /*␊ |
882 | This function returns two values, one in the lower 16 bits of the return␊ |
883 | value, and the other in the remaining upper bits, obtained by shifting the␊ |
884 | return value down 16 bits. If the upper value is -1 and the lower value is␊ |
885 | zero, then inflate() is currently decoding information outside of a block.␊ |
886 | If the upper value is -1 and the lower value is non-zero, then inflate is in␊ |
887 | the middle of a stored block, with the lower value equaling the number of␊ |
888 | bytes from the input remaining to copy. If the upper value is not -1, then␊ |
889 | it is the number of bits back from the current bit position in the input of␊ |
890 | the code (literal or length/distance pair) currently being processed. In␊ |
891 | that case the lower value is the number of bytes already emitted for that␊ |
892 | code.␊ |
893 | ␊ |
894 | A code is being processed if inflate is waiting for more input to complete␊ |
895 | decoding of the code, or if it has completed decoding but is waiting for␊ |
896 | more output space to write the literal or match data.␊ |
897 | ␊ |
898 | inflateMark() is used to mark locations in the input data for random␊ |
899 | access, which may be at bit positions, and to note those cases where the␊ |
900 | output of a code may span boundaries of random access blocks. The current␊ |
901 | location in the input stream can be determined from avail_in and data_type␊ |
902 | as noted in the description for the Z_BLOCK flush parameter for inflate.␊ |
903 | ␊ |
904 | inflateMark returns the value noted above or -1 << 16 if the provided␊ |
905 | source stream state was inconsistent.␊ |
906 | */␊ |
907 | ␊ |
908 | ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,␊ |
909 | gz_headerp head));␊ |
910 | /*␊ |
911 | inflateGetHeader() requests that gzip header information be stored in the␊ |
912 | provided gz_header structure. inflateGetHeader() may be called after␊ |
913 | inflateInit2() or inflateReset(), and before the first call of inflate().␊ |
914 | As inflate() processes the gzip stream, head->done is zero until the header␊ |
915 | is completed, at which time head->done is set to one. If a zlib stream is␊ |
916 | being decoded, then head->done is set to -1 to indicate that there will be␊ |
917 | no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be␊ |
918 | used to force inflate() to return immediately after header processing is␊ |
919 | complete and before any actual data is decompressed.␊ |
920 | ␊ |
921 | The text, time, xflags, and os fields are filled in with the gzip header␊ |
922 | contents. hcrc is set to true if there is a header CRC. (The header CRC␊ |
923 | was valid if done is set to one.) If extra is not Z_NULL, then extra_max␊ |
924 | contains the maximum number of bytes to write to extra. Once done is true,␊ |
925 | extra_len contains the actual extra field length, and extra contains the␊ |
926 | extra field, or that field truncated if extra_max is less than extra_len.␊ |
927 | If name is not Z_NULL, then up to name_max characters are written there,␊ |
928 | terminated with a zero unless the length is greater than name_max. If␊ |
929 | comment is not Z_NULL, then up to comm_max characters are written there,␊ |
930 | terminated with a zero unless the length is greater than comm_max. When any␊ |
931 | of extra, name, or comment are not Z_NULL and the respective field is not␊ |
932 | present in the header, then that field is set to Z_NULL to signal its␊ |
933 | absence. This allows the use of deflateSetHeader() with the returned␊ |
934 | structure to duplicate the header. However if those fields are set to␊ |
935 | allocated memory, then the application will need to save those pointers␊ |
936 | elsewhere so that they can be eventually freed.␊ |
937 | ␊ |
938 | If inflateGetHeader is not used, then the header information is simply␊ |
939 | discarded. The header is always checked for validity, including the header␊ |
940 | CRC if present. inflateReset() will reset the process to discard the header␊ |
941 | information. The application would need to call inflateGetHeader() again to␊ |
942 | retrieve the header from the next gzip stream.␊ |
943 | ␊ |
944 | inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source␊ |
945 | stream state was inconsistent.␊ |
946 | */␊ |
947 | ␊ |
948 | /*␊ |
949 | ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,␊ |
950 | unsigned char FAR *window));␊ |
951 | ␊ |
952 | Initialize the internal stream state for decompression using inflateBack()␊ |
953 | calls. The fields zalloc, zfree and opaque in strm must be initialized␊ |
954 | before the call. If zalloc and zfree are Z_NULL, then the default library-␊ |
955 | derived memory allocation routines are used. windowBits is the base two␊ |
956 | logarithm of the window size, in the range 8..15. window is a caller␊ |
957 | supplied buffer of that size. Except for special applications where it is␊ |
958 | assured that deflate was used with small window sizes, windowBits must be 15␊ |
959 | and a 32K byte window must be supplied to be able to decompress general␊ |
960 | deflate streams.␊ |
961 | ␊ |
962 | See inflateBack() for the usage of these routines.␊ |
963 | ␊ |
964 | inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of␊ |
965 | the paramaters are invalid, Z_MEM_ERROR if the internal state could not be␊ |
966 | allocated, or Z_VERSION_ERROR if the version of the library does not match␊ |
967 | the version of the header file.␊ |
968 | */␊ |
969 | ␊ |
970 | typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));␊ |
971 | typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));␊ |
972 | ␊ |
973 | ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,␊ |
974 | in_func in, void FAR *in_desc,␊ |
975 | out_func out, void FAR *out_desc));␊ |
976 | /*␊ |
977 | inflateBack() does a raw inflate with a single call using a call-back␊ |
978 | interface for input and output. This is more efficient than inflate() for␊ |
979 | file i/o applications in that it avoids copying between the output and the␊ |
980 | sliding window by simply making the window itself the output buffer. This␊ |
981 | function trusts the application to not change the output buffer passed by␊ |
982 | the output function, at least until inflateBack() returns.␊ |
983 | ␊ |
984 | inflateBackInit() must be called first to allocate the internal state␊ |
985 | and to initialize the state with the user-provided window buffer.␊ |
986 | inflateBack() may then be used multiple times to inflate a complete, raw␊ |
987 | deflate stream with each call. inflateBackEnd() is then called to free the␊ |
988 | allocated state.␊ |
989 | ␊ |
990 | A raw deflate stream is one with no zlib or gzip header or trailer.␊ |
991 | This routine would normally be used in a utility that reads zip or gzip␊ |
992 | files and writes out uncompressed files. The utility would decode the␊ |
993 | header and process the trailer on its own, hence this routine expects only␊ |
994 | the raw deflate stream to decompress. This is different from the normal␊ |
995 | behavior of inflate(), which expects either a zlib or gzip header and␊ |
996 | trailer around the deflate stream.␊ |
997 | ␊ |
998 | inflateBack() uses two subroutines supplied by the caller that are then␊ |
999 | called by inflateBack() for input and output. inflateBack() calls those␊ |
1000 | routines until it reads a complete deflate stream and writes out all of the␊ |
1001 | uncompressed data, or until it encounters an error. The function's␊ |
1002 | parameters and return types are defined above in the in_func and out_func␊ |
1003 | typedefs. inflateBack() will call in(in_desc, &buf) which should return the␊ |
1004 | number of bytes of provided input, and a pointer to that input in buf. If␊ |
1005 | there is no input available, in() must return zero--buf is ignored in that␊ |
1006 | case--and inflateBack() will return a buffer error. inflateBack() will call␊ |
1007 | out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()␊ |
1008 | should return zero on success, or non-zero on failure. If out() returns␊ |
1009 | non-zero, inflateBack() will return with an error. Neither in() nor out()␊ |
1010 | are permitted to change the contents of the window provided to␊ |
1011 | inflateBackInit(), which is also the buffer that out() uses to write from.␊ |
1012 | The length written by out() will be at most the window size. Any non-zero␊ |
1013 | amount of input may be provided by in().␊ |
1014 | ␊ |
1015 | For convenience, inflateBack() can be provided input on the first call by␊ |
1016 | setting strm->next_in and strm->avail_in. If that input is exhausted, then␊ |
1017 | in() will be called. Therefore strm->next_in must be initialized before␊ |
1018 | calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called␊ |
1019 | immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in␊ |
1020 | must also be initialized, and then if strm->avail_in is not zero, input will␊ |
1021 | initially be taken from strm->next_in[0 .. strm->avail_in - 1].␊ |
1022 | ␊ |
1023 | The in_desc and out_desc parameters of inflateBack() is passed as the␊ |
1024 | first parameter of in() and out() respectively when they are called. These␊ |
1025 | descriptors can be optionally used to pass any information that the caller-␊ |
1026 | supplied in() and out() functions need to do their job.␊ |
1027 | ␊ |
1028 | On return, inflateBack() will set strm->next_in and strm->avail_in to␊ |
1029 | pass back any unused input that was provided by the last in() call. The␊ |
1030 | return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR␊ |
1031 | if in() or out() returned an error, Z_DATA_ERROR if there was a format error␊ |
1032 | in the deflate stream (in which case strm->msg is set to indicate the nature␊ |
1033 | of the error), or Z_STREAM_ERROR if the stream was not properly initialized.␊ |
1034 | In the case of Z_BUF_ERROR, an input or output error can be distinguished␊ |
1035 | using strm->next_in which will be Z_NULL only if in() returned an error. If␊ |
1036 | strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning␊ |
1037 | non-zero. (in() will always be called before out(), so strm->next_in is␊ |
1038 | assured to be defined if out() returns non-zero.) Note that inflateBack()␊ |
1039 | cannot return Z_OK.␊ |
1040 | */␊ |
1041 | ␊ |
1042 | ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));␊ |
1043 | /*␊ |
1044 | All memory allocated by inflateBackInit() is freed.␊ |
1045 | ␊ |
1046 | inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream␊ |
1047 | state was inconsistent.␊ |
1048 | */␊ |
1049 | ␊ |
1050 | ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));␊ |
1051 | /* Return flags indicating compile-time options.␊ |
1052 | ␊ |
1053 | Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:␊ |
1054 | 1.0: size of uInt␊ |
1055 | 3.2: size of uLong␊ |
1056 | 5.4: size of voidpf (pointer)␊ |
1057 | 7.6: size of z_off_t␊ |
1058 | ␊ |
1059 | Compiler, assembler, and debug options:␊ |
1060 | 8: DEBUG␊ |
1061 | 9: ASMV or ASMINF -- use ASM code␊ |
1062 | 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention␊ |
1063 | 11: 0 (reserved)␊ |
1064 | ␊ |
1065 | One-time table building (smaller code, but not thread-safe if true):␊ |
1066 | 12: BUILDFIXED -- build static block decoding tables when needed␊ |
1067 | 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed␊ |
1068 | 14,15: 0 (reserved)␊ |
1069 | ␊ |
1070 | Library content (indicates missing functionality):␊ |
1071 | 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking␊ |
1072 | deflate code when not needed)␊ |
1073 | 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect␊ |
1074 | and decode gzip streams (to avoid linking crc code)␊ |
1075 | 18-19: 0 (reserved)␊ |
1076 | ␊ |
1077 | Operation variations (changes in library functionality):␊ |
1078 | 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate␊ |
1079 | 21: FASTEST -- deflate algorithm with only one, lowest compression level␊ |
1080 | 22,23: 0 (reserved)␊ |
1081 | ␊ |
1082 | The sprintf variant used by gzprintf (zero is best):␊ |
1083 | 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format␊ |
1084 | 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!␊ |
1085 | 26: 0 = returns value, 1 = void -- 1 means inferred string length returned␊ |
1086 | ␊ |
1087 | Remainder:␊ |
1088 | 27-31: 0 (reserved)␊ |
1089 | */␊ |
1090 | ␊ |
1091 | ␊ |
1092 | /* utility functions */␊ |
1093 | ␊ |
1094 | /*␊ |
1095 | The following utility functions are implemented on top of the basic␊ |
1096 | stream-oriented functions. To simplify the interface, some default options␊ |
1097 | are assumed (compression level and memory usage, standard memory allocation␊ |
1098 | functions). The source code of these utility functions can be modified if␊ |
1099 | you need special options.␊ |
1100 | */␊ |
1101 | ␊ |
1102 | ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,␊ |
1103 | const Bytef *source, uLong sourceLen));␊ |
1104 | /*␊ |
1105 | Compresses the source buffer into the destination buffer. sourceLen is␊ |
1106 | the byte length of the source buffer. Upon entry, destLen is the total size␊ |
1107 | of the destination buffer, which must be at least the value returned by␊ |
1108 | compressBound(sourceLen). Upon exit, destLen is the actual size of the␊ |
1109 | compressed buffer.␊ |
1110 | ␊ |
1111 | compress returns Z_OK if success, Z_MEM_ERROR if there was not␊ |
1112 | enough memory, Z_BUF_ERROR if there was not enough room in the output␊ |
1113 | buffer.␊ |
1114 | */␊ |
1115 | ␊ |
1116 | ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,␊ |
1117 | const Bytef *source, uLong sourceLen,␊ |
1118 | int level));␊ |
1119 | /*␊ |
1120 | Compresses the source buffer into the destination buffer. The level␊ |
1121 | parameter has the same meaning as in deflateInit. sourceLen is the byte␊ |
1122 | length of the source buffer. Upon entry, destLen is the total size of the␊ |
1123 | destination buffer, which must be at least the value returned by␊ |
1124 | compressBound(sourceLen). Upon exit, destLen is the actual size of the␊ |
1125 | compressed buffer.␊ |
1126 | ␊ |
1127 | compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough␊ |
1128 | memory, Z_BUF_ERROR if there was not enough room in the output buffer,␊ |
1129 | Z_STREAM_ERROR if the level parameter is invalid.␊ |
1130 | */␊ |
1131 | ␊ |
1132 | ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));␊ |
1133 | /*␊ |
1134 | compressBound() returns an upper bound on the compressed size after␊ |
1135 | compress() or compress2() on sourceLen bytes. It would be used before a␊ |
1136 | compress() or compress2() call to allocate the destination buffer.␊ |
1137 | */␊ |
1138 | ␊ |
1139 | ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,␊ |
1140 | const Bytef *source, uLong sourceLen));␊ |
1141 | /*␊ |
1142 | Decompresses the source buffer into the destination buffer. sourceLen is␊ |
1143 | the byte length of the source buffer. Upon entry, destLen is the total size␊ |
1144 | of the destination buffer, which must be large enough to hold the entire␊ |
1145 | uncompressed data. (The size of the uncompressed data must have been saved␊ |
1146 | previously by the compressor and transmitted to the decompressor by some␊ |
1147 | mechanism outside the scope of this compression library.) Upon exit, destLen␊ |
1148 | is the actual size of the uncompressed buffer.␊ |
1149 | ␊ |
1150 | uncompress returns Z_OK if success, Z_MEM_ERROR if there was not␊ |
1151 | enough memory, Z_BUF_ERROR if there was not enough room in the output␊ |
1152 | buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.␊ |
1153 | */␊ |
1154 | ␊ |
1155 | ␊ |
1156 | /* gzip file access functions */␊ |
1157 | ␊ |
1158 | /*␊ |
1159 | This library supports reading and writing files in gzip (.gz) format with␊ |
1160 | an interface similar to that of stdio, using the functions that start with␊ |
1161 | "gz". The gzip format is different from the zlib format. gzip is a gzip␊ |
1162 | wrapper, documented in RFC 1952, wrapped around a deflate stream.␊ |
1163 | */␊ |
1164 | ␊ |
1165 | typedef voidp gzFile; /* opaque gzip file descriptor */␊ |
1166 | ␊ |
1167 | /*␊ |
1168 | ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));␊ |
1169 | ␊ |
1170 | Opens a gzip (.gz) file for reading or writing. The mode parameter is as␊ |
1171 | in fopen ("rb" or "wb") but can also include a compression level ("wb9") or␊ |
1172 | a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only␊ |
1173 | compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'␊ |
1174 | for fixed code compression as in "wb9F". (See the description of␊ |
1175 | deflateInit2 for more information about the strategy parameter.) Also "a"␊ |
1176 | can be used instead of "w" to request that the gzip stream that will be␊ |
1177 | written be appended to the file. "+" will result in an error, since reading␊ |
1178 | and writing to the same gzip file is not supported.␊ |
1179 | ␊ |
1180 | gzopen can be used to read a file which is not in gzip format; in this␊ |
1181 | case gzread will directly read from the file without decompression.␊ |
1182 | ␊ |
1183 | gzopen returns NULL if the file could not be opened, if there was␊ |
1184 | insufficient memory to allocate the gzFile state, or if an invalid mode was␊ |
1185 | specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).␊ |
1186 | errno can be checked to determine if the reason gzopen failed was that the␊ |
1187 | file could not be opened.␊ |
1188 | */␊ |
1189 | ␊ |
1190 | ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));␊ |
1191 | /*␊ |
1192 | gzdopen associates a gzFile with the file descriptor fd. File descriptors␊ |
1193 | are obtained from calls like open, dup, creat, pipe or fileno (if the file␊ |
1194 | has been previously opened with fopen). The mode parameter is as in gzopen.␊ |
1195 | ␊ |
1196 | The next call of gzclose on the returned gzFile will also close the file␊ |
1197 | descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor␊ |
1198 | fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,␊ |
1199 | mode);. The duplicated descriptor should be saved to avoid a leak, since␊ |
1200 | gzdopen does not close fd if it fails.␊ |
1201 | ␊ |
1202 | gzdopen returns NULL if there was insufficient memory to allocate the␊ |
1203 | gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not␊ |
1204 | provided, or '+' was provided), or if fd is -1. The file descriptor is not␊ |
1205 | used until the next gz* read, write, seek, or close operation, so gzdopen␊ |
1206 | will not detect if fd is invalid (unless fd is -1).␊ |
1207 | */␊ |
1208 | ␊ |
1209 | ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));␊ |
1210 | /*␊ |
1211 | Set the internal buffer size used by this library's functions. The␊ |
1212 | default buffer size is 8192 bytes. This function must be called after␊ |
1213 | gzopen() or gzdopen(), and before any other calls that read or write the␊ |
1214 | file. The buffer memory allocation is always deferred to the first read or␊ |
1215 | write. Two buffers are allocated, either both of the specified size when␊ |
1216 | writing, or one of the specified size and the other twice that size when␊ |
1217 | reading. A larger buffer size of, for example, 64K or 128K bytes will␊ |
1218 | noticeably increase the speed of decompression (reading).␊ |
1219 | ␊ |
1220 | The new buffer size also affects the maximum length for gzprintf().␊ |
1221 | ␊ |
1222 | gzbuffer() returns 0 on success, or -1 on failure, such as being called␊ |
1223 | too late.␊ |
1224 | */␊ |
1225 | ␊ |
1226 | ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));␊ |
1227 | /*␊ |
1228 | Dynamically update the compression level or strategy. See the description␊ |
1229 | of deflateInit2 for the meaning of these parameters.␊ |
1230 | ␊ |
1231 | gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not␊ |
1232 | opened for writing.␊ |
1233 | */␊ |
1234 | ␊ |
1235 | ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));␊ |
1236 | /*␊ |
1237 | Reads the given number of uncompressed bytes from the compressed file. If␊ |
1238 | the input file was not in gzip format, gzread copies the given number of␊ |
1239 | bytes into the buffer.␊ |
1240 | ␊ |
1241 | After reaching the end of a gzip stream in the input, gzread will continue␊ |
1242 | to read, looking for another gzip stream, or failing that, reading the rest␊ |
1243 | of the input file directly without decompression. The entire input file␊ |
1244 | will be read if gzread is called until it returns less than the requested␊ |
1245 | len.␊ |
1246 | ␊ |
1247 | gzread returns the number of uncompressed bytes actually read, less than␊ |
1248 | len for end of file, or -1 for error.␊ |
1249 | */␊ |
1250 | ␊ |
1251 | ZEXTERN int ZEXPORT gzwrite OF((gzFile file,␊ |
1252 | voidpc buf, unsigned len));␊ |
1253 | /*␊ |
1254 | Writes the given number of uncompressed bytes into the compressed file.␊ |
1255 | gzwrite returns the number of uncompressed bytes written or 0 in case of␊ |
1256 | error.␊ |
1257 | */␊ |
1258 | ␊ |
1259 | ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));␊ |
1260 | /*␊ |
1261 | Converts, formats, and writes the arguments to the compressed file under␊ |
1262 | control of the format string, as in fprintf. gzprintf returns the number of␊ |
1263 | uncompressed bytes actually written, or 0 in case of error. The number of␊ |
1264 | uncompressed bytes written is limited to 8191, or one less than the buffer␊ |
1265 | size given to gzbuffer(). The caller should assure that this limit is not␊ |
1266 | exceeded. If it is exceeded, then gzprintf() will return an error (0) with␊ |
1267 | nothing written. In this case, there may also be a buffer overflow with␊ |
1268 | unpredictable consequences, which is possible only if zlib was compiled with␊ |
1269 | the insecure functions sprintf() or vsprintf() because the secure snprintf()␊ |
1270 | or vsnprintf() functions were not available. This can be determined using␊ |
1271 | zlibCompileFlags().␊ |
1272 | */␊ |
1273 | ␊ |
1274 | ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));␊ |
1275 | /*␊ |
1276 | Writes the given null-terminated string to the compressed file, excluding␊ |
1277 | the terminating null character.␊ |
1278 | ␊ |
1279 | gzputs returns the number of characters written, or -1 in case of error.␊ |
1280 | */␊ |
1281 | ␊ |
1282 | ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));␊ |
1283 | /*␊ |
1284 | Reads bytes from the compressed file until len-1 characters are read, or a␊ |
1285 | newline character is read and transferred to buf, or an end-of-file␊ |
1286 | condition is encountered. If any characters are read or if len == 1, the␊ |
1287 | string is terminated with a null character. If no characters are read due␊ |
1288 | to an end-of-file or len < 1, then the buffer is left untouched.␊ |
1289 | ␊ |
1290 | gzgets returns buf which is a null-terminated string, or it returns NULL␊ |
1291 | for end-of-file or in case of error. If there was an error, the contents at␊ |
1292 | buf are indeterminate.␊ |
1293 | */␊ |
1294 | ␊ |
1295 | ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));␊ |
1296 | /*␊ |
1297 | Writes c, converted to an unsigned char, into the compressed file. gzputc␊ |
1298 | returns the value that was written, or -1 in case of error.␊ |
1299 | */␊ |
1300 | ␊ |
1301 | ZEXTERN int ZEXPORT gzgetc OF((gzFile file));␊ |
1302 | /*␊ |
1303 | Reads one byte from the compressed file. gzgetc returns this byte or -1␊ |
1304 | in case of end of file or error.␊ |
1305 | */␊ |
1306 | ␊ |
1307 | ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));␊ |
1308 | /*␊ |
1309 | Push one character back onto the stream to be read as the first character␊ |
1310 | on the next read. At least one character of push-back is allowed.␊ |
1311 | gzungetc() returns the character pushed, or -1 on failure. gzungetc() will␊ |
1312 | fail if c is -1, and may fail if a character has been pushed but not read␊ |
1313 | yet. If gzungetc is used immediately after gzopen or gzdopen, at least the␊ |
1314 | output buffer size of pushed characters is allowed. (See gzbuffer above.)␊ |
1315 | The pushed character will be discarded if the stream is repositioned with␊ |
1316 | gzseek() or gzrewind().␊ |
1317 | */␊ |
1318 | ␊ |
1319 | ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));␊ |
1320 | /*␊ |
1321 | Flushes all pending output into the compressed file. The parameter flush␊ |
1322 | is as in the deflate() function. The return value is the zlib error number␊ |
1323 | (see function gzerror below). gzflush is only permitted when writing.␊ |
1324 | ␊ |
1325 | If the flush parameter is Z_FINISH, the remaining data is written and the␊ |
1326 | gzip stream is completed in the output. If gzwrite() is called again, a new␊ |
1327 | gzip stream will be started in the output. gzread() is able to read such␊ |
1328 | concatented gzip streams.␊ |
1329 | ␊ |
1330 | gzflush should be called only when strictly necessary because it will␊ |
1331 | degrade compression if called too often.␊ |
1332 | */␊ |
1333 | ␊ |
1334 | /*␊ |
1335 | ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,␊ |
1336 | z_off_t offset, int whence));␊ |
1337 | ␊ |
1338 | Sets the starting position for the next gzread or gzwrite on the given␊ |
1339 | compressed file. The offset represents a number of bytes in the␊ |
1340 | uncompressed data stream. The whence parameter is defined as in lseek(2);␊ |
1341 | the value SEEK_END is not supported.␊ |
1342 | ␊ |
1343 | If the file is opened for reading, this function is emulated but can be␊ |
1344 | extremely slow. If the file is opened for writing, only forward seeks are␊ |
1345 | supported; gzseek then compresses a sequence of zeroes up to the new␊ |
1346 | starting position.␊ |
1347 | ␊ |
1348 | gzseek returns the resulting offset location as measured in bytes from␊ |
1349 | the beginning of the uncompressed stream, or -1 in case of error, in␊ |
1350 | particular if the file is opened for writing and the new starting position␊ |
1351 | would be before the current position.␊ |
1352 | */␊ |
1353 | ␊ |
1354 | ZEXTERN int ZEXPORT gzrewind OF((gzFile file));␊ |
1355 | /*␊ |
1356 | Rewinds the given file. This function is supported only for reading.␊ |
1357 | ␊ |
1358 | gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)␊ |
1359 | */␊ |
1360 | ␊ |
1361 | /*␊ |
1362 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));␊ |
1363 | ␊ |
1364 | Returns the starting position for the next gzread or gzwrite on the given␊ |
1365 | compressed file. This position represents a number of bytes in the␊ |
1366 | uncompressed data stream, and is zero when starting, even if appending or␊ |
1367 | reading a gzip stream from the middle of a file using gzdopen().␊ |
1368 | ␊ |
1369 | gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)␊ |
1370 | */␊ |
1371 | ␊ |
1372 | /*␊ |
1373 | ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));␊ |
1374 | ␊ |
1375 | Returns the current offset in the file being read or written. This offset␊ |
1376 | includes the count of bytes that precede the gzip stream, for example when␊ |
1377 | appending or when using gzdopen() for reading. When reading, the offset␊ |
1378 | does not include as yet unused buffered input. This information can be used␊ |
1379 | for a progress indicator. On error, gzoffset() returns -1.␊ |
1380 | */␊ |
1381 | ␊ |
1382 | ZEXTERN int ZEXPORT gzeof OF((gzFile file));␊ |
1383 | /*␊ |
1384 | Returns true (1) if the end-of-file indicator has been set while reading,␊ |
1385 | false (0) otherwise. Note that the end-of-file indicator is set only if the␊ |
1386 | read tried to go past the end of the input, but came up short. Therefore,␊ |
1387 | just like feof(), gzeof() may return false even if there is no more data to␊ |
1388 | read, in the event that the last read request was for the exact number of␊ |
1389 | bytes remaining in the input file. This will happen if the input file size␊ |
1390 | is an exact multiple of the buffer size.␊ |
1391 | ␊ |
1392 | If gzeof() returns true, then the read functions will return no more data,␊ |
1393 | unless the end-of-file indicator is reset by gzclearerr() and the input file␊ |
1394 | has grown since the previous end of file was detected.␊ |
1395 | */␊ |
1396 | ␊ |
1397 | ZEXTERN int ZEXPORT gzdirect OF((gzFile file));␊ |
1398 | /*␊ |
1399 | Returns true (1) if file is being copied directly while reading, or false␊ |
1400 | (0) if file is a gzip stream being decompressed. This state can change from␊ |
1401 | false to true while reading the input file if the end of a gzip stream is␊ |
1402 | reached, but is followed by data that is not another gzip stream.␊ |
1403 | ␊ |
1404 | If the input file is empty, gzdirect() will return true, since the input␊ |
1405 | does not contain a gzip stream.␊ |
1406 | ␊ |
1407 | If gzdirect() is used immediately after gzopen() or gzdopen() it will␊ |
1408 | cause buffers to be allocated to allow reading the file to determine if it␊ |
1409 | is a gzip file. Therefore if gzbuffer() is used, it should be called before␊ |
1410 | gzdirect().␊ |
1411 | */␊ |
1412 | ␊ |
1413 | ZEXTERN int ZEXPORT gzclose OF((gzFile file));␊ |
1414 | /*␊ |
1415 | Flushes all pending output if necessary, closes the compressed file and␊ |
1416 | deallocates the (de)compression state. Note that once file is closed, you␊ |
1417 | cannot call gzerror with file, since its structures have been deallocated.␊ |
1418 | gzclose must not be called more than once on the same file, just as free␊ |
1419 | must not be called more than once on the same allocation.␊ |
1420 | ␊ |
1421 | gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a␊ |
1422 | file operation error, or Z_OK on success.␊ |
1423 | */␊ |
1424 | ␊ |
1425 | ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));␊ |
1426 | ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));␊ |
1427 | /*␊ |
1428 | Same as gzclose(), but gzclose_r() is only for use when reading, and␊ |
1429 | gzclose_w() is only for use when writing or appending. The advantage to␊ |
1430 | using these instead of gzclose() is that they avoid linking in zlib␊ |
1431 | compression or decompression code that is not used when only reading or only␊ |
1432 | writing respectively. If gzclose() is used, then both compression and␊ |
1433 | decompression code will be included the application when linking to a static␊ |
1434 | zlib library.␊ |
1435 | */␊ |
1436 | ␊ |
1437 | ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));␊ |
1438 | /*␊ |
1439 | Returns the error message for the last error which occurred on the given␊ |
1440 | compressed file. errnum is set to zlib error number. If an error occurred␊ |
1441 | in the file system and not in the compression library, errnum is set to␊ |
1442 | Z_ERRNO and the application may consult errno to get the exact error code.␊ |
1443 | ␊ |
1444 | The application must not modify the returned string. Future calls to␊ |
1445 | this function may invalidate the previously returned string. If file is␊ |
1446 | closed, then the string previously returned by gzerror will no longer be␊ |
1447 | available.␊ |
1448 | ␊ |
1449 | gzerror() should be used to distinguish errors from end-of-file for those␊ |
1450 | functions above that do not distinguish those cases in their return values.␊ |
1451 | */␊ |
1452 | ␊ |
1453 | ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));␊ |
1454 | /*␊ |
1455 | Clears the error and end-of-file flags for file. This is analogous to the␊ |
1456 | clearerr() function in stdio. This is useful for continuing to read a gzip␊ |
1457 | file that is being written concurrently.␊ |
1458 | */␊ |
1459 | ␊ |
1460 | ␊ |
1461 | /* checksum functions */␊ |
1462 | ␊ |
1463 | /*␊ |
1464 | These functions are not related to compression but are exported␊ |
1465 | anyway because they might be useful in applications using the compression␊ |
1466 | library.␊ |
1467 | */␊ |
1468 | ␊ |
1469 | ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));␊ |
1470 | /*␊ |
1471 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and␊ |
1472 | return the updated checksum. If buf is Z_NULL, this function returns the␊ |
1473 | required initial value for the checksum.␊ |
1474 | ␊ |
1475 | An Adler-32 checksum is almost as reliable as a CRC32 but can be computed␊ |
1476 | much faster.␊ |
1477 | ␊ |
1478 | Usage example:␊ |
1479 | ␊ |
1480 | uLong adler = adler32(0L, Z_NULL, 0);␊ |
1481 | ␊ |
1482 | while (read_buffer(buffer, length) != EOF) {␊ |
1483 | adler = adler32(adler, buffer, length);␊ |
1484 | }␊ |
1485 | if (adler != original_adler) error();␊ |
1486 | */␊ |
1487 | ␊ |
1488 | /*␊ |
1489 | ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,␊ |
1490 | z_off_t len2));␊ |
1491 | ␊ |
1492 | Combine two Adler-32 checksums into one. For two sequences of bytes, seq1␊ |
1493 | and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for␊ |
1494 | each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of␊ |
1495 | seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.␊ |
1496 | */␊ |
1497 | ␊ |
1498 | ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));␊ |
1499 | /*␊ |
1500 | Update a running CRC-32 with the bytes buf[0..len-1] and return the␊ |
1501 | updated CRC-32. If buf is Z_NULL, this function returns the required␊ |
1502 | initial value for the for the crc. Pre- and post-conditioning (one's␊ |
1503 | complement) is performed within this function so it shouldn't be done by the␊ |
1504 | application.␊ |
1505 | ␊ |
1506 | Usage example:␊ |
1507 | ␊ |
1508 | uLong crc = crc32(0L, Z_NULL, 0);␊ |
1509 | ␊ |
1510 | while (read_buffer(buffer, length) != EOF) {␊ |
1511 | crc = crc32(crc, buffer, length);␊ |
1512 | }␊ |
1513 | if (crc != original_crc) error();␊ |
1514 | */␊ |
1515 | ␊ |
1516 | /*␊ |
1517 | ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));␊ |
1518 | ␊ |
1519 | Combine two CRC-32 check values into one. For two sequences of bytes,␊ |
1520 | seq1 and seq2 with lengths len1 and len2, CRC-32 check values were␊ |
1521 | calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32␊ |
1522 | check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and␊ |
1523 | len2.␊ |
1524 | */␊ |
1525 | ␊ |
1526 | ␊ |
1527 | /* various hacks, don't look :) */␊ |
1528 | ␊ |
1529 | /* deflateInit and inflateInit are macros to allow checking the zlib version␊ |
1530 | * and the compiler's view of z_stream:␊ |
1531 | */␊ |
1532 | ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,␊ |
1533 | const char *version, int stream_size));␊ |
1534 | ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,␊ |
1535 | const char *version, int stream_size));␊ |
1536 | ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,␊ |
1537 | int windowBits, int memLevel,␊ |
1538 | int strategy, const char *version,␊ |
1539 | int stream_size));␊ |
1540 | ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,␊ |
1541 | const char *version, int stream_size));␊ |
1542 | ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,␊ |
1543 | unsigned char FAR *window,␊ |
1544 | const char *version,␊ |
1545 | int stream_size));␊ |
1546 | #define deflateInit(strm, level) \␊ |
1547 | deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))␊ |
1548 | #define inflateInit(strm) \␊ |
1549 | inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))␊ |
1550 | #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \␊ |
1551 | deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\␊ |
1552 | (strategy), ZLIB_VERSION, sizeof(z_stream))␊ |
1553 | #define inflateInit2(strm, windowBits) \␊ |
1554 | inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))␊ |
1555 | #define inflateBackInit(strm, windowBits, window) \␊ |
1556 | inflateBackInit_((strm), (windowBits), (window), \␊ |
1557 | ZLIB_VERSION, sizeof(z_stream))␊ |
1558 | ␊ |
1559 | /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or␊ |
1560 | * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if␊ |
1561 | * both are true, the application gets the *64 functions, and the regular␊ |
1562 | * functions are changed to 64 bits) -- in case these are set on systems␊ |
1563 | * without large file support, _LFS64_LARGEFILE must also be true␊ |
1564 | */␊ |
1565 | #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0␊ |
1566 | ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));␊ |
1567 | ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));␊ |
1568 | ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));␊ |
1569 | ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));␊ |
1570 | ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));␊ |
1571 | ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));␊ |
1572 | #endif␊ |
1573 | ␊ |
1574 | #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0␊ |
1575 | # define gzopen gzopen64␊ |
1576 | # define gzseek gzseek64␊ |
1577 | # define gztell gztell64␊ |
1578 | # define gzoffset gzoffset64␊ |
1579 | # define adler32_combine adler32_combine64␊ |
1580 | # define crc32_combine crc32_combine64␊ |
1581 | # ifdef _LARGEFILE64_SOURCE␊ |
1582 | ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));␊ |
1583 | ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));␊ |
1584 | ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));␊ |
1585 | ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));␊ |
1586 | ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));␊ |
1587 | ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));␊ |
1588 | # endif␊ |
1589 | #else␊ |
1590 | ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));␊ |
1591 | ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));␊ |
1592 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));␊ |
1593 | ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));␊ |
1594 | ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));␊ |
1595 | ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));␊ |
1596 | #endif␊ |
1597 | ␊ |
1598 | /* hack for buggy compilers */␊ |
1599 | #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)␊ |
1600 | struct internal_state {int dummy;};␊ |
1601 | #endif␊ |
1602 | ␊ |
1603 | /* undocumented functions */␊ |
1604 | ZEXTERN const char * ZEXPORT zError OF((int));␊ |
1605 | ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));␊ |
1606 | ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));␊ |
1607 | ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));␊ |
1608 | ␊ |
1609 | ␊ |
1610 | ␊ |
1611 | void _inflateInit_ (void);␊ |
1612 | ␊ |
1613 | ␊ |
1614 | #ifdef __cplusplus␊ |
1615 | }␊ |
1616 | #endif␊ |
1617 | ␊ |
1618 | #endif /* ZLIB_H */␊ |
1619 | |