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c45f211e | 1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
43743d63 | 2 | version 1.2.5, April 19th, 2010 |
c45f211e | 3 | |
43743d63 | 4 | Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler |
c45f211e TT |
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 | |
17210dff | 27 | Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt |
c45f211e TT |
28 | (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). |
29 | */ | |
30 | ||
17210dff TT |
31 | #ifndef ZLIB_H |
32 | #define ZLIB_H | |
c45f211e TT |
33 | |
34 | #include "zconf.h" | |
35 | ||
36 | #ifdef __cplusplus | |
37 | extern "C" { | |
38 | #endif | |
39 | ||
43743d63 MK |
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 | |
c45f211e | 46 | |
17210dff | 47 | /* |
43743d63 MK |
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 | |
c45f211e TT |
57 | (providing more output space) before each call. |
58 | ||
43743d63 | 59 | The compressed data format used by default by the in-memory functions is |
ef338166 TT |
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. | |
17210dff | 62 | |
43743d63 | 63 | The library also supports reading and writing files in gzip (.gz) format |
17210dff TT |
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 | ||
43743d63 | 68 | This library can optionally read and write gzip streams in memory as well. |
ef338166 | 69 | |
43743d63 | 70 | The zlib format was designed to be compact and fast for use in memory |
17210dff TT |
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 | ||
43743d63 MK |
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. | |
c45f211e TT |
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 | ||
ef338166 | 101 | int data_type; /* best guess about the data type: binary or text */ |
c45f211e TT |
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 | ||
ef338166 TT |
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 | ||
c45f211e | 131 | /* |
43743d63 MK |
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 | |
c45f211e TT |
141 | opaque value. |
142 | ||
43743d63 | 143 | zalloc must return Z_NULL if there is not enough memory for the object. |
c45f211e TT |
144 | If zlib is used in a multi-threaded application, zalloc and zfree must be |
145 | thread safe. | |
146 | ||
43743d63 MK |
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). | |
c45f211e TT |
160 | */ |
161 | ||
162 | /* constants */ | |
163 | ||
164 | #define Z_NO_FLUSH 0 | |
43743d63 | 165 | #define Z_PARTIAL_FLUSH 1 |
c45f211e TT |
166 | #define Z_SYNC_FLUSH 2 |
167 | #define Z_FULL_FLUSH 3 | |
168 | #define Z_FINISH 4 | |
17210dff | 169 | #define Z_BLOCK 5 |
43743d63 | 170 | #define Z_TREES 6 |
17210dff | 171 | /* Allowed flush values; see deflate() and inflate() below for details */ |
c45f211e TT |
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) | |
43743d63 MK |
182 | /* Return codes for the compression/decompression functions. Negative values |
183 | * are errors, positive values are used for special but normal events. | |
c45f211e TT |
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 | |
17210dff | 194 | #define Z_RLE 3 |
ef338166 | 195 | #define Z_FIXED 4 |
c45f211e TT |
196 | #define Z_DEFAULT_STRATEGY 0 |
197 | /* compression strategy; see deflateInit2() below for details */ | |
198 | ||
199 | #define Z_BINARY 0 | |
ef338166 TT |
200 | #define Z_TEXT 1 |
201 | #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ | |
c45f211e | 202 | #define Z_UNKNOWN 2 |
17210dff | 203 | /* Possible values of the data_type field (though see inflate()) */ |
c45f211e TT |
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 | ||
43743d63 | 213 | |
c45f211e TT |
214 | /* basic functions */ |
215 | ||
216 | ZEXTERN const char * ZEXPORT zlibVersion OF((void)); | |
217 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. | |
43743d63 MK |
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. | |
c45f211e TT |
221 | */ |
222 | ||
17210dff | 223 | /* |
c45f211e TT |
224 | ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); |
225 | ||
43743d63 MK |
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. | |
c45f211e TT |
230 | |
231 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: | |
43743d63 MK |
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). | |
c45f211e | 236 | |
43743d63 MK |
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 | |
c45f211e | 239 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
43743d63 MK |
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(). | |
c45f211e TT |
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 | |
43743d63 MK |
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 | |
c45f211e TT |
251 | forced to flush. |
252 | ||
43743d63 | 253 | The detailed semantics are as follows. deflate performs one or both of the |
c45f211e TT |
254 | following actions: |
255 | ||
256 | - Compress more input starting at next_in and update next_in and avail_in | |
43743d63 | 257 | accordingly. If not all input can be processed (because there is not |
c45f211e TT |
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 | |
43743d63 | 262 | accordingly. This action is forced if the parameter flush is non zero. |
c45f211e | 263 | Forcing flush frequently degrades the compression ratio, so this parameter |
43743d63 MK |
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. | |
c45f211e | 275 | |
ef338166 | 276 | Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to |
43743d63 | 277 | decide how much data to accumulate before producing output, in order to |
ef338166 TT |
278 | maximize compression. |
279 | ||
c45f211e TT |
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 | |
43743d63 MK |
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. | |
c45f211e TT |
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 | |
43743d63 | 310 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
ef338166 | 311 | compression. |
c45f211e TT |
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 | |
43743d63 | 316 | avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
17210dff TT |
317 | avail_out is greater than six to avoid repeated flush markers due to |
318 | avail_out == 0 on return. | |
c45f211e TT |
319 | |
320 | If the parameter flush is set to Z_FINISH, pending input is processed, | |
43743d63 MK |
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 | |
c45f211e | 323 | called again with Z_FINISH and more output space (updated avail_out) but no |
43743d63 MK |
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. | |
17210dff | 327 | |
c45f211e | 328 | Z_FINISH can be used immediately after deflateInit if all the compression |
43743d63 MK |
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 | |
c45f211e TT |
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 | ||
ef338166 | 336 | deflate() may update strm->data_type if it can make a good guess about |
43743d63 MK |
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. | |
c45f211e TT |
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 | |
43743d63 MK |
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 | |
17210dff TT |
347 | fatal, and deflate() can be called again with more input and more output |
348 | space to continue compressing. | |
c45f211e TT |
349 | */ |
350 | ||
351 | ||
352 | ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); | |
353 | /* | |
354 | All dynamically allocated data structures for this stream are freed. | |
43743d63 MK |
355 | This function discards any unprocessed input and does not flush any pending |
356 | output. | |
c45f211e TT |
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 | |
43743d63 MK |
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 | |
c45f211e TT |
362 | deallocated). |
363 | */ | |
364 | ||
365 | ||
17210dff | 366 | /* |
c45f211e TT |
367 | ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
368 | ||
43743d63 | 369 | Initializes the internal stream state for decompression. The fields |
c45f211e | 370 | next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
43743d63 MK |
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 | |
c45f211e TT |
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 | |
43743d63 MK |
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. | |
c45f211e TT |
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 | |
43743d63 | 394 | buffer becomes empty or the output buffer becomes full. It may introduce |
17210dff TT |
395 | some output latency (reading input without producing any output) except when |
396 | forced to flush. | |
c45f211e | 397 | |
43743d63 | 398 | The detailed semantics are as follows. inflate performs one or both of the |
c45f211e TT |
399 | following actions: |
400 | ||
401 | - Decompress more input starting at next_in and update next_in and avail_in | |
43743d63 MK |
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(). | |
c45f211e TT |
405 | |
406 | - Provide more output starting at next_out and update next_out and avail_out | |
43743d63 MK |
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. | |
17210dff TT |
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 | |
43743d63 MK |
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. | |
c45f211e TT |
449 | |
450 | inflate() should normally be called until it returns Z_STREAM_END or an | |
43743d63 MK |
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. | |
c45f211e | 460 | |
17210dff TT |
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 | |
43743d63 | 463 | first call. So the only effect of the flush parameter in this implementation |
17210dff | 464 | is on the return value of inflate(), as noted below, or when it returns early |
43743d63 | 465 | because Z_BLOCK or Z_TREES is used. |
17210dff TT |
466 | |
467 | If a preset dictionary is needed after this call (see inflateSetDictionary | |
ef338166 | 468 | below), inflate sets strm->adler to the adler32 checksum of the dictionary |
17210dff TT |
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 | |
43743d63 | 472 | below. At the end of the stream, inflate() checks that its computed adler32 |
17210dff TT |
473 | checksum is equal to that saved by the compressor and returns Z_STREAM_END |
474 | only if the checksum is correct. | |
475 | ||
43743d63 MK |
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. | |
c45f211e TT |
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 | |
17210dff TT |
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 | |
43743d63 | 489 | next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, |
17210dff | 490 | Z_BUF_ERROR if no progress is possible or if there was not enough room in the |
43743d63 | 491 | output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
17210dff | 492 | inflate() can be called again with more input and more output space to |
43743d63 MK |
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. | |
c45f211e TT |
496 | */ |
497 | ||
498 | ||
499 | ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); | |
500 | /* | |
501 | All dynamically allocated data structures for this stream are freed. | |
43743d63 MK |
502 | This function discards any unprocessed input and does not flush any pending |
503 | output. | |
c45f211e TT |
504 | |
505 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state | |
43743d63 | 506 | was inconsistent. In the error case, msg may be set but then points to a |
c45f211e TT |
507 | static string (which must not be deallocated). |
508 | */ | |
509 | ||
43743d63 | 510 | |
c45f211e TT |
511 | /* Advanced functions */ |
512 | ||
513 | /* | |
514 | The following functions are needed only in some special applications. | |
515 | */ | |
516 | ||
17210dff | 517 | /* |
c45f211e TT |
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 | ||
43743d63 MK |
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. | |
c45f211e | 528 | |
43743d63 | 529 | The method parameter is the compression method. It must be Z_DEFLATED in |
c45f211e TT |
530 | this version of the library. |
531 | ||
532 | The windowBits parameter is the base two logarithm of the window size | |
43743d63 MK |
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 | |
c45f211e TT |
536 | deflateInit is used instead. |
537 | ||
43743d63 MK |
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 | |
17210dff TT |
540 | with no zlib header or trailer, and will not compute an adler32 check value. |
541 | ||
43743d63 | 542 | windowBits can also be greater than 15 for optional gzip encoding. Add |
17210dff | 543 | 16 to windowBits to write a simple gzip header and trailer around the |
43743d63 MK |
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 | |
ef338166 | 547 | gzip stream is being written, strm->adler is a crc32 instead of an adler32. |
17210dff | 548 | |
c45f211e | 549 | The memLevel parameter specifies how much memory should be allocated |
43743d63 MK |
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. | |
c45f211e | 554 | |
43743d63 | 555 | The strategy parameter is used to tune the compression algorithm. Use the |
c45f211e | 556 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
17210dff TT |
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 | |
43743d63 MK |
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 | |
17210dff | 562 | coding and less string matching; it is somewhat intermediate between |
43743d63 MK |
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(). | |
c45f211e | 576 | */ |
17210dff | 577 | |
c45f211e TT |
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 | |
43743d63 MK |
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 | |
c45f211e TT |
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 | |
43743d63 | 590 | used strings preferably put towards the end of the dictionary. Using a |
c45f211e TT |
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 | |
43743d63 MK |
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. | |
c45f211e | 602 | |
17210dff | 603 | Upon return of this function, strm->adler is set to the adler32 value |
c45f211e | 604 | of the dictionary; the decompressor may later use this value to determine |
43743d63 | 605 | which dictionary has been used by the compressor. (The adler32 value |
c45f211e | 606 | applies to the whole dictionary even if only a subset of the dictionary is |
17210dff TT |
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. | |
c45f211e TT |
609 | |
610 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a | |
43743d63 | 611 | parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
c45f211e | 612 | inconsistent (for example if deflate has already been called for this stream |
43743d63 | 613 | or if the compression method is bsort). deflateSetDictionary does not |
c45f211e TT |
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 | |
43743d63 | 624 | data with a filter. The streams that will be discarded should then be freed |
c45f211e | 625 | by calling deflateEnd. Note that deflateCopy duplicates the internal |
43743d63 MK |
626 | compression state which can be quite large, so this strategy is slow and can |
627 | consume lots of memory. | |
c45f211e TT |
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 | |
43743d63 | 631 | (such as zalloc being Z_NULL). msg is left unchanged in both source and |
c45f211e TT |
632 | destination. |
633 | */ | |
634 | ||
635 | ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); | |
636 | /* | |
637 | This function is equivalent to deflateEnd followed by deflateInit, | |
43743d63 MK |
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. | |
c45f211e | 641 | |
43743d63 MK |
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). | |
c45f211e TT |
644 | */ |
645 | ||
646 | ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, | |
17210dff TT |
647 | int level, |
648 | int strategy)); | |
c45f211e TT |
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 | |
43743d63 MK |
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(). | |
c45f211e TT |
657 | |
658 | Before the call of deflateParams, the stream state must be set as for | |
43743d63 MK |
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. | |
c45f211e TT |
661 | |
662 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source | |
43743d63 MK |
663 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if |
664 | strm->avail_out was zero. | |
c45f211e TT |
665 | */ |
666 | ||
ef338166 TT |
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 | ||
17210dff TT |
684 | ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, |
685 | uLong sourceLen)); | |
686 | /* | |
687 | deflateBound() returns an upper bound on the compressed size after | |
43743d63 MK |
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(). | |
17210dff TT |
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 | |
43743d63 MK |
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 | |
17210dff TT |
707 | stream state was inconsistent. |
708 | */ | |
709 | ||
ef338166 TT |
710 | ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, |
711 | gz_headerp head)); | |
712 | /* | |
43743d63 | 713 | deflateSetHeader() provides gzip header information for when a gzip |
ef338166 TT |
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 | ||
43743d63 | 726 | If deflateSetHeader is not used, the default gzip header has text false, |
ef338166 TT |
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 | ||
43743d63 | 730 | deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
ef338166 TT |
731 | stream state was inconsistent. |
732 | */ | |
733 | ||
17210dff | 734 | /* |
c45f211e TT |
735 | ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
736 | int windowBits)); | |
737 | ||
43743d63 | 738 | This is another version of inflateInit with an extra parameter. The |
c45f211e TT |
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 | |
43743d63 MK |
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 | |
17210dff | 746 | provided to deflateInit2() while compressing, or it must be equal to 15 if |
43743d63 | 747 | deflateInit2() was not used. If a compressed stream with a larger window |
17210dff TT |
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 | ||
43743d63 MK |
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, | |
17210dff | 756 | not looking for a zlib or gzip header, not generating a check value, and not |
43743d63 | 757 | looking for any check values for comparison at the end of the stream. This |
17210dff | 758 | is for use with other formats that use the deflate compressed data format |
43743d63 | 759 | such as zip. Those formats provide their own check values. If a custom |
17210dff TT |
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 | |
43743d63 | 763 | most applications, the zlib format should be used as is. Note that comments |
17210dff TT |
764 | above on the use in deflateInit2() applies to the magnitude of windowBits. |
765 | ||
43743d63 | 766 | windowBits can also be greater than 15 for optional gzip decoding. Add |
17210dff TT |
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 | |
43743d63 MK |
769 | return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a |
770 | crc32 instead of an adler32. | |
17210dff TT |
771 | |
772 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
43743d63 MK |
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. | |
c45f211e TT |
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 | |
43743d63 MK |
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 | |
ef338166 TT |
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. | |
c45f211e TT |
797 | |
798 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a | |
43743d63 | 799 | parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
c45f211e | 800 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
43743d63 | 801 | expected one (incorrect adler32 value). inflateSetDictionary does not |
c45f211e TT |
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)); | |
17210dff | 807 | /* |
43743d63 MK |
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. | |
c45f211e TT |
819 | */ |
820 | ||
17210dff TT |
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 | |
43743d63 | 833 | (such as zalloc being Z_NULL). msg is left unchanged in both source and |
17210dff TT |
834 | destination. |
835 | */ | |
836 | ||
c45f211e TT |
837 | ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); |
838 | /* | |
839 | This function is equivalent to inflateEnd followed by inflateInit, | |
43743d63 MK |
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. | |
c45f211e | 842 | |
43743d63 MK |
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. | |
c45f211e TT |
857 | */ |
858 | ||
ef338166 TT |
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 | |
43743d63 MK |
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 | |
ef338166 TT |
877 | stream state was inconsistent. |
878 | */ | |
879 | ||
43743d63 MK |
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 | ||
ef338166 TT |
908 | ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, |
909 | gz_headerp head)); | |
17210dff | 910 | /* |
43743d63 | 911 | inflateGetHeader() requests that gzip header information be stored in the |
ef338166 TT |
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 | |
43743d63 MK |
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. | |
ef338166 | 920 | |
43743d63 | 921 | The text, time, xflags, and os fields are filled in with the gzip header |
ef338166 | 922 | contents. hcrc is set to true if there is a header CRC. (The header CRC |
43743d63 | 923 | was valid if done is set to one.) If extra is not Z_NULL, then extra_max |
ef338166 TT |
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, | |
43743d63 MK |
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 | |
ef338166 TT |
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 | ||
43743d63 | 938 | If inflateGetHeader is not used, then the header information is simply |
ef338166 TT |
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 | ||
43743d63 | 944 | inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
ef338166 TT |
945 | stream state was inconsistent. |
946 | */ | |
947 | ||
948 | /* | |
949 | ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, | |
17210dff TT |
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 | |
43743d63 MK |
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. | |
17210dff TT |
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 | ||
ef338166 | 973 | ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, |
17210dff TT |
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 | |
43743d63 MK |
987 | deflate stream with each call. inflateBackEnd() is then called to free the |
988 | allocated state. | |
17210dff TT |
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 | |
43743d63 MK |
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 | |
17210dff TT |
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 | |
43743d63 | 1021 | initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
17210dff TT |
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 | |
43743d63 MK |
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. | |
17210dff TT |
1040 | */ |
1041 | ||
ef338166 | 1042 | ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); |
17210dff TT |
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 | ||
c45f211e TT |
1091 | |
1092 | /* utility functions */ | |
1093 | ||
1094 | /* | |
43743d63 MK |
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. | |
c45f211e TT |
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 | |
43743d63 MK |
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 | |
c45f211e | 1109 | compressed buffer. |
43743d63 | 1110 | |
c45f211e TT |
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 | /* | |
43743d63 | 1120 | Compresses the source buffer into the destination buffer. The level |
c45f211e | 1121 | parameter has the same meaning as in deflateInit. sourceLen is the byte |
43743d63 | 1122 | length of the source buffer. Upon entry, destLen is the total size of the |
17210dff | 1123 | destination buffer, which must be at least the value returned by |
43743d63 | 1124 | compressBound(sourceLen). Upon exit, destLen is the actual size of the |
17210dff | 1125 | compressed buffer. |
c45f211e TT |
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 | ||
17210dff TT |
1132 | ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); |
1133 | /* | |
1134 | compressBound() returns an upper bound on the compressed size after | |
43743d63 MK |
1135 | compress() or compress2() on sourceLen bytes. It would be used before a |
1136 | compress() or compress2() call to allocate the destination buffer. | |
17210dff TT |
1137 | */ |
1138 | ||
c45f211e TT |
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 | |
43743d63 MK |
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. | |
c45f211e TT |
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 | |
17210dff | 1152 | buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. |
c45f211e TT |
1153 | */ |
1154 | ||
1155 | ||
43743d63 MK |
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 */ | |
c45f211e | 1166 | |
c45f211e | 1167 | /* |
43743d63 MK |
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. | |
c45f211e TT |
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 | ||
43743d63 MK |
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 | */ | |
c45f211e | 1189 | |
43743d63 | 1190 | ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
c45f211e | 1191 | /* |
43743d63 MK |
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. | |
c45f211e TT |
1224 | */ |
1225 | ||
1226 | ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); | |
1227 | /* | |
43743d63 | 1228 | Dynamically update the compression level or strategy. See the description |
c45f211e | 1229 | of deflateInit2 for the meaning of these parameters. |
43743d63 | 1230 | |
c45f211e TT |
1231 | gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
1232 | opened for writing. | |
1233 | */ | |
1234 | ||
43743d63 | 1235 | ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
c45f211e | 1236 | /* |
43743d63 MK |
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 | */ | |
c45f211e | 1250 | |
43743d63 MK |
1251 | ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
1252 | voidpc buf, unsigned len)); | |
c45f211e TT |
1253 | /* |
1254 | Writes the given number of uncompressed bytes into the compressed file. | |
43743d63 MK |
1255 | gzwrite returns the number of uncompressed bytes written or 0 in case of |
1256 | error. | |
c45f211e TT |
1257 | */ |
1258 | ||
43743d63 | 1259 | ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
c45f211e | 1260 | /* |
43743d63 MK |
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(). | |
c45f211e TT |
1272 | */ |
1273 | ||
1274 | ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); | |
1275 | /* | |
43743d63 | 1276 | Writes the given null-terminated string to the compressed file, excluding |
c45f211e | 1277 | the terminating null character. |
43743d63 MK |
1278 | |
1279 | gzputs returns the number of characters written, or -1 in case of error. | |
c45f211e TT |
1280 | */ |
1281 | ||
1282 | ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); | |
1283 | /* | |
43743d63 MK |
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. | |
c45f211e TT |
1293 | */ |
1294 | ||
43743d63 | 1295 | ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
c45f211e | 1296 | /* |
43743d63 MK |
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. | |
c45f211e TT |
1299 | */ |
1300 | ||
43743d63 | 1301 | ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
c45f211e | 1302 | /* |
43743d63 MK |
1303 | Reads one byte from the compressed file. gzgetc returns this byte or -1 |
1304 | in case of end of file or error. | |
c45f211e TT |
1305 | */ |
1306 | ||
43743d63 | 1307 | ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); |
17210dff | 1308 | /* |
43743d63 MK |
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(). | |
17210dff TT |
1317 | */ |
1318 | ||
43743d63 | 1319 | ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
c45f211e | 1320 | /* |
43743d63 MK |
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. | |
c45f211e TT |
1332 | */ |
1333 | ||
17210dff | 1334 | /* |
43743d63 MK |
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); | |
c45f211e | 1341 | the value SEEK_END is not supported. |
43743d63 | 1342 | |
c45f211e | 1343 | If the file is opened for reading, this function is emulated but can be |
43743d63 | 1344 | extremely slow. If the file is opened for writing, only forward seeks are |
c45f211e TT |
1345 | supported; gzseek then compresses a sequence of zeroes up to the new |
1346 | starting position. | |
1347 | ||
43743d63 | 1348 | gzseek returns the resulting offset location as measured in bytes from |
c45f211e TT |
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 | ||
43743d63 | 1358 | gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
c45f211e TT |
1359 | */ |
1360 | ||
43743d63 | 1361 | /* |
c45f211e | 1362 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
43743d63 MK |
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 | ||
c45f211e | 1372 | /* |
43743d63 | 1373 | ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); |
c45f211e | 1374 | |
43743d63 MK |
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. | |
c45f211e TT |
1380 | */ |
1381 | ||
1382 | ZEXTERN int ZEXPORT gzeof OF((gzFile file)); | |
1383 | /* | |
43743d63 MK |
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. | |
c45f211e TT |
1395 | */ |
1396 | ||
ef338166 TT |
1397 | ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); |
1398 | /* | |
43743d63 MK |
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(). | |
ef338166 TT |
1411 | */ |
1412 | ||
c45f211e TT |
1413 | ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
1414 | /* | |
43743d63 MK |
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. | |
c45f211e TT |
1435 | */ |
1436 | ||
1437 | ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); | |
1438 | /* | |
43743d63 MK |
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. | |
c45f211e TT |
1451 | */ |
1452 | ||
17210dff TT |
1453 | ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); |
1454 | /* | |
43743d63 MK |
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 | |
17210dff TT |
1457 | file that is being written concurrently. |
1458 | */ | |
1459 | ||
43743d63 | 1460 | |
c45f211e TT |
1461 | /* checksum functions */ |
1462 | ||
1463 | /* | |
1464 | These functions are not related to compression but are exported | |
43743d63 MK |
1465 | anyway because they might be useful in applications using the compression |
1466 | library. | |
c45f211e TT |
1467 | */ |
1468 | ||
1469 | ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); | |
c45f211e TT |
1470 | /* |
1471 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and | |
43743d63 MK |
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: | |
c45f211e TT |
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 | ||
43743d63 | 1488 | /* |
ef338166 TT |
1489 | ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, |
1490 | z_off_t len2)); | |
43743d63 | 1491 | |
ef338166 TT |
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 | ||
c45f211e TT |
1498 | ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
1499 | /* | |
ef338166 | 1500 | Update a running CRC-32 with the bytes buf[0..len-1] and return the |
43743d63 MK |
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 | ||
c45f211e TT |
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 | ||
43743d63 | 1516 | /* |
ef338166 TT |
1517 | ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); |
1518 | ||
ef338166 TT |
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 | ||
c45f211e TT |
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)); | |
ef338166 | 1542 | ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, |
17210dff TT |
1543 | unsigned char FAR *window, |
1544 | const char *version, | |
1545 | int stream_size)); | |
c45f211e TT |
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)) | |
17210dff TT |
1555 | #define inflateBackInit(strm, windowBits, window) \ |
1556 | inflateBackInit_((strm), (windowBits), (window), \ | |
43743d63 | 1557 | ZLIB_VERSION, sizeof(z_stream)) |
c45f211e | 1558 | |
43743d63 MK |
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 | |
c45f211e | 1597 | |
43743d63 | 1598 | /* hack for buggy compilers */ |
17210dff | 1599 | #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
43743d63 | 1600 | struct internal_state {int dummy;}; |
c45f211e TT |
1601 | #endif |
1602 | ||
43743d63 | 1603 | /* undocumented functions */ |
ef338166 | 1604 | ZEXTERN const char * ZEXPORT zError OF((int)); |
43743d63 | 1605 | ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); |
c45f211e | 1606 | ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
43743d63 | 1607 | ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); |
c45f211e TT |
1608 | |
1609 | #ifdef __cplusplus | |
1610 | } | |
1611 | #endif | |
1612 | ||
17210dff | 1613 | #endif /* ZLIB_H */ |