Robert Bieber | 7c52284 | 2010-07-21 07:45:29 +0000 | [diff] [blame] | 1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
| 2 | version 1.2.2, October 3rd, 2004 |
| 3 | |
| 4 | Copyright (C) 1995-2004 Jean-loup Gailly and Mark Adler |
| 5 | |
| 6 | This software is provided 'as-is', without any express or implied |
| 7 | warranty. In no event will the authors be held liable for any damages |
| 8 | arising from the use of this software. |
| 9 | |
| 10 | Permission is granted to anyone to use this software for any purpose, |
| 11 | including commercial applications, and to alter it and redistribute it |
| 12 | freely, subject to the following restrictions: |
| 13 | |
| 14 | 1. The origin of this software must not be misrepresented; you must not |
| 15 | claim that you wrote the original software. If you use this software |
| 16 | in a product, an acknowledgment in the product documentation would be |
| 17 | appreciated but is not required. |
| 18 | 2. Altered source versions must be plainly marked as such, and must not be |
| 19 | misrepresented as being the original software. |
| 20 | 3. This notice may not be removed or altered from any source distribution. |
| 21 | |
| 22 | Jean-loup Gailly Mark Adler |
| 23 | jloup@gzip.org madler@alumni.caltech.edu |
| 24 | |
| 25 | |
| 26 | The data format used by the zlib library is described by RFCs (Request for |
| 27 | Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt |
| 28 | (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). |
| 29 | */ |
| 30 | |
| 31 | #ifndef ZLIB_H |
| 32 | #define ZLIB_H |
| 33 | |
| 34 | #include "zconf.h" |
| 35 | |
| 36 | #ifdef __cplusplus |
| 37 | extern "C" { |
| 38 | #endif |
| 39 | |
| 40 | #define ZLIB_VERSION "1.2.2" |
| 41 | #define ZLIB_VERNUM 0x1220 |
| 42 | |
| 43 | /* |
| 44 | The 'zlib' compression library provides in-memory compression and |
| 45 | decompression functions, including integrity checks of the uncompressed |
| 46 | data. This version of the library supports only one compression method |
| 47 | (deflation) but other algorithms will be added later and will have the same |
| 48 | stream interface. |
| 49 | |
| 50 | Compression can be done in a single step if the buffers are large |
| 51 | enough (for example if an input file is mmap'ed), or can be done by |
| 52 | repeated calls of the compression function. In the latter case, the |
| 53 | application must provide more input and/or consume the output |
| 54 | (providing more output space) before each call. |
| 55 | |
| 56 | The compressed data format used by default by the in-memory functions is |
| 57 | the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped |
| 58 | around a deflate stream, which is itself documented in RFC 1951. |
| 59 | |
| 60 | The library also supports reading and writing files in gzip (.gz) format |
| 61 | with an interface similar to that of stdio using the functions that start |
| 62 | with "gz". The gzip format is different from the zlib format. gzip is a |
| 63 | gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. |
| 64 | |
| 65 | This library can optionally read and write gzip streams in memory as well. |
| 66 | |
| 67 | The zlib format was designed to be compact and fast for use in memory |
| 68 | and on communications channels. The gzip format was designed for single- |
| 69 | file compression on file systems, has a larger header than zlib to maintain |
| 70 | directory information, and uses a different, slower check method than zlib. |
| 71 | |
| 72 | The library does not install any signal handler. The decoder checks |
| 73 | the consistency of the compressed data, so the library should never |
| 74 | crash even in case of corrupted input. |
| 75 | */ |
| 76 | |
| 77 | typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
| 78 | typedef void (*free_func) OF((voidpf opaque, voidpf address)); |
| 79 | |
| 80 | struct internal_state; |
| 81 | |
| 82 | typedef struct z_stream_s { |
| 83 | Bytef *next_in; /* next input byte */ |
| 84 | uInt avail_in; /* number of bytes available at next_in */ |
| 85 | uLong total_in; /* total nb of input bytes read so far */ |
| 86 | |
| 87 | Bytef *next_out; /* next output byte should be put there */ |
| 88 | uInt avail_out; /* remaining free space at next_out */ |
| 89 | uLong total_out; /* total nb of bytes output so far */ |
| 90 | |
| 91 | char *msg; /* last error message, NULL if no error */ |
| 92 | struct internal_state FAR *state; /* not visible by applications */ |
| 93 | |
| 94 | alloc_func zalloc; /* used to allocate the internal state */ |
| 95 | free_func zfree; /* used to free the internal state */ |
| 96 | voidpf opaque; /* private data object passed to zalloc and zfree */ |
| 97 | |
| 98 | int data_type; /* best guess about the data type: ascii or binary */ |
| 99 | uLong adler; /* adler32 value of the uncompressed data */ |
| 100 | uLong reserved; /* reserved for future use */ |
| 101 | } z_stream; |
| 102 | |
| 103 | typedef z_stream FAR *z_streamp; |
| 104 | |
| 105 | /* |
| 106 | The application must update next_in and avail_in when avail_in has |
| 107 | dropped to zero. It must update next_out and avail_out when avail_out |
| 108 | has dropped to zero. The application must initialize zalloc, zfree and |
| 109 | opaque before calling the init function. All other fields are set by the |
| 110 | compression library and must not be updated by the application. |
| 111 | |
| 112 | The opaque value provided by the application will be passed as the first |
| 113 | parameter for calls of zalloc and zfree. This can be useful for custom |
| 114 | memory management. The compression library attaches no meaning to the |
| 115 | opaque value. |
| 116 | |
| 117 | zalloc must return Z_NULL if there is not enough memory for the object. |
| 118 | If zlib is used in a multi-threaded application, zalloc and zfree must be |
| 119 | thread safe. |
| 120 | |
| 121 | On 16-bit systems, the functions zalloc and zfree must be able to allocate |
| 122 | exactly 65536 bytes, but will not be required to allocate more than this |
| 123 | if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, |
| 124 | pointers returned by zalloc for objects of exactly 65536 bytes *must* |
| 125 | have their offset normalized to zero. The default allocation function |
| 126 | provided by this library ensures this (see zutil.c). To reduce memory |
| 127 | requirements and avoid any allocation of 64K objects, at the expense of |
| 128 | compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). |
| 129 | |
| 130 | The fields total_in and total_out can be used for statistics or |
| 131 | progress reports. After compression, total_in holds the total size of |
| 132 | the uncompressed data and may be saved for use in the decompressor |
| 133 | (particularly if the decompressor wants to decompress everything in |
| 134 | a single step). |
| 135 | */ |
| 136 | |
| 137 | /* constants */ |
| 138 | |
| 139 | #define Z_NO_FLUSH 0 |
| 140 | #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ |
| 141 | #define Z_SYNC_FLUSH 2 |
| 142 | #define Z_FULL_FLUSH 3 |
| 143 | #define Z_FINISH 4 |
| 144 | #define Z_BLOCK 5 |
| 145 | /* Allowed flush values; see deflate() and inflate() below for details */ |
| 146 | |
| 147 | #define Z_OK 0 |
| 148 | #define Z_STREAM_END 1 |
| 149 | #define Z_NEED_DICT 2 |
| 150 | #define Z_ERRNO (-1) |
| 151 | #define Z_STREAM_ERROR (-2) |
| 152 | #define Z_DATA_ERROR (-3) |
| 153 | #define Z_MEM_ERROR (-4) |
| 154 | #define Z_BUF_ERROR (-5) |
| 155 | #define Z_VERSION_ERROR (-6) |
| 156 | /* Return codes for the compression/decompression functions. Negative |
| 157 | * values are errors, positive values are used for special but normal events. |
| 158 | */ |
| 159 | |
| 160 | #define Z_NO_COMPRESSION 0 |
| 161 | #define Z_BEST_SPEED 1 |
| 162 | #define Z_BEST_COMPRESSION 9 |
| 163 | #define Z_DEFAULT_COMPRESSION (-1) |
| 164 | /* compression levels */ |
| 165 | |
| 166 | #define Z_FILTERED 1 |
| 167 | #define Z_HUFFMAN_ONLY 2 |
| 168 | #define Z_RLE 3 |
| 169 | #define Z_DEFAULT_STRATEGY 0 |
| 170 | /* compression strategy; see deflateInit2() below for details */ |
| 171 | |
| 172 | #define Z_BINARY 0 |
| 173 | #define Z_ASCII 1 |
| 174 | #define Z_UNKNOWN 2 |
| 175 | /* Possible values of the data_type field (though see inflate()) */ |
| 176 | |
| 177 | #define Z_DEFLATED 8 |
| 178 | /* The deflate compression method (the only one supported in this version) */ |
| 179 | |
| 180 | #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
| 181 | |
| 182 | #define zlib_version zlibVersion() |
| 183 | /* for compatibility with versions < 1.0.2 */ |
| 184 | |
| 185 | /* basic functions */ |
| 186 | |
| 187 | ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
| 188 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
| 189 | If the first character differs, the library code actually used is |
| 190 | not compatible with the zlib.h header file used by the application. |
| 191 | This check is automatically made by deflateInit and inflateInit. |
| 192 | */ |
| 193 | |
| 194 | /* |
| 195 | ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); |
| 196 | |
| 197 | Initializes the internal stream state for compression. The fields |
| 198 | zalloc, zfree and opaque must be initialized before by the caller. |
| 199 | If zalloc and zfree are set to Z_NULL, deflateInit updates them to |
| 200 | use default allocation functions. |
| 201 | |
| 202 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
| 203 | 1 gives best speed, 9 gives best compression, 0 gives no compression at |
| 204 | all (the input data is simply copied a block at a time). |
| 205 | Z_DEFAULT_COMPRESSION requests a default compromise between speed and |
| 206 | compression (currently equivalent to level 6). |
| 207 | |
| 208 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
| 209 | enough memory, Z_STREAM_ERROR if level is not a valid compression level, |
| 210 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
| 211 | with the version assumed by the caller (ZLIB_VERSION). |
| 212 | msg is set to null if there is no error message. deflateInit does not |
| 213 | perform any compression: this will be done by deflate(). |
| 214 | */ |
| 215 | |
| 216 | |
| 217 | ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
| 218 | /* |
| 219 | deflate compresses as much data as possible, and stops when the input |
| 220 | buffer becomes empty or the output buffer becomes full. It may introduce some |
| 221 | output latency (reading input without producing any output) except when |
| 222 | forced to flush. |
| 223 | |
| 224 | The detailed semantics are as follows. deflate performs one or both of the |
| 225 | following actions: |
| 226 | |
| 227 | - Compress more input starting at next_in and update next_in and avail_in |
| 228 | accordingly. If not all input can be processed (because there is not |
| 229 | enough room in the output buffer), next_in and avail_in are updated and |
| 230 | processing will resume at this point for the next call of deflate(). |
| 231 | |
| 232 | - Provide more output starting at next_out and update next_out and avail_out |
| 233 | accordingly. This action is forced if the parameter flush is non zero. |
| 234 | Forcing flush frequently degrades the compression ratio, so this parameter |
| 235 | should be set only when necessary (in interactive applications). |
| 236 | Some output may be provided even if flush is not set. |
| 237 | |
| 238 | Before the call of deflate(), the application should ensure that at least |
| 239 | one of the actions is possible, by providing more input and/or consuming |
| 240 | more output, and updating avail_in or avail_out accordingly; avail_out |
| 241 | should never be zero before the call. The application can consume the |
| 242 | compressed output when it wants, for example when the output buffer is full |
| 243 | (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK |
| 244 | and with zero avail_out, it must be called again after making room in the |
| 245 | output buffer because there might be more output pending. |
| 246 | |
| 247 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
| 248 | flushed to the output buffer and the output is aligned on a byte boundary, so |
| 249 | that the decompressor can get all input data available so far. (In particular |
| 250 | avail_in is zero after the call if enough output space has been provided |
| 251 | before the call.) Flushing may degrade compression for some compression |
| 252 | algorithms and so it should be used only when necessary. |
| 253 | |
| 254 | If flush is set to Z_FULL_FLUSH, all output is flushed as with |
| 255 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
| 256 | restart from this point if previous compressed data has been damaged or if |
| 257 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
| 258 | the compression. |
| 259 | |
| 260 | If deflate returns with avail_out == 0, this function must be called again |
| 261 | with the same value of the flush parameter and more output space (updated |
| 262 | avail_out), until the flush is complete (deflate returns with non-zero |
| 263 | avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
| 264 | avail_out is greater than six to avoid repeated flush markers due to |
| 265 | avail_out == 0 on return. |
| 266 | |
| 267 | If the parameter flush is set to Z_FINISH, pending input is processed, |
| 268 | pending output is flushed and deflate returns with Z_STREAM_END if there |
| 269 | was enough output space; if deflate returns with Z_OK, this function must be |
| 270 | called again with Z_FINISH and more output space (updated avail_out) but no |
| 271 | more input data, until it returns with Z_STREAM_END or an error. After |
| 272 | deflate has returned Z_STREAM_END, the only possible operations on the |
| 273 | stream are deflateReset or deflateEnd. |
| 274 | |
| 275 | Z_FINISH can be used immediately after deflateInit if all the compression |
| 276 | is to be done in a single step. In this case, avail_out must be at least |
| 277 | the value returned by deflateBound (see below). If deflate does not return |
| 278 | Z_STREAM_END, then it must be called again as described above. |
| 279 | |
| 280 | deflate() sets strm->adler to the adler32 checksum of all input read |
| 281 | so far (that is, total_in bytes). |
| 282 | |
| 283 | deflate() may update data_type if it can make a good guess about |
| 284 | the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered |
| 285 | binary. This field is only for information purposes and does not affect |
| 286 | the compression algorithm in any manner. |
| 287 | |
| 288 | deflate() returns Z_OK if some progress has been made (more input |
| 289 | processed or more output produced), Z_STREAM_END if all input has been |
| 290 | consumed and all output has been produced (only when flush is set to |
| 291 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
| 292 | if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
| 293 | (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not |
| 294 | fatal, and deflate() can be called again with more input and more output |
| 295 | space to continue compressing. |
| 296 | */ |
| 297 | |
| 298 | |
| 299 | ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); |
| 300 | /* |
| 301 | All dynamically allocated data structures for this stream are freed. |
| 302 | This function discards any unprocessed input and does not flush any |
| 303 | pending output. |
| 304 | |
| 305 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
| 306 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
| 307 | prematurely (some input or output was discarded). In the error case, |
| 308 | msg may be set but then points to a static string (which must not be |
| 309 | deallocated). |
| 310 | */ |
| 311 | |
| 312 | |
| 313 | /* |
| 314 | ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
| 315 | |
| 316 | Initializes the internal stream state for decompression. The fields |
| 317 | next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
| 318 | the caller. If next_in is not Z_NULL and avail_in is large enough (the exact |
| 319 | value depends on the compression method), inflateInit determines the |
| 320 | compression method from the zlib header and allocates all data structures |
| 321 | accordingly; otherwise the allocation will be deferred to the first call of |
| 322 | inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to |
| 323 | use default allocation functions. |
| 324 | |
| 325 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 326 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
| 327 | version assumed by the caller. msg is set to null if there is no error |
| 328 | message. inflateInit does not perform any decompression apart from reading |
| 329 | the zlib header if present: this will be done by inflate(). (So next_in and |
| 330 | avail_in may be modified, but next_out and avail_out are unchanged.) |
| 331 | */ |
| 332 | |
| 333 | |
| 334 | ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); |
| 335 | /* |
| 336 | inflate decompresses as much data as possible, and stops when the input |
| 337 | buffer becomes empty or the output buffer becomes full. It may introduce |
| 338 | some output latency (reading input without producing any output) except when |
| 339 | forced to flush. |
| 340 | |
| 341 | The detailed semantics are as follows. inflate performs one or both of the |
| 342 | following actions: |
| 343 | |
| 344 | - Decompress more input starting at next_in and update next_in and avail_in |
| 345 | accordingly. If not all input can be processed (because there is not |
| 346 | enough room in the output buffer), next_in is updated and processing |
| 347 | will resume at this point for the next call of inflate(). |
| 348 | |
| 349 | - Provide more output starting at next_out and update next_out and avail_out |
| 350 | accordingly. inflate() provides as much output as possible, until there |
| 351 | is no more input data or no more space in the output buffer (see below |
| 352 | about the flush parameter). |
| 353 | |
| 354 | Before the call of inflate(), the application should ensure that at least |
| 355 | one of the actions is possible, by providing more input and/or consuming |
| 356 | more output, and updating the next_* and avail_* values accordingly. |
| 357 | The application can consume the uncompressed output when it wants, for |
| 358 | example when the output buffer is full (avail_out == 0), or after each |
| 359 | call of inflate(). If inflate returns Z_OK and with zero avail_out, it |
| 360 | must be called again after making room in the output buffer because there |
| 361 | might be more output pending. |
| 362 | |
| 363 | The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, |
| 364 | Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much |
| 365 | output as possible to the output buffer. Z_BLOCK requests that inflate() stop |
| 366 | if and when it get to the next deflate block boundary. When decoding the zlib |
| 367 | or gzip format, this will cause inflate() to return immediately after the |
| 368 | header and before the first block. When doing a raw inflate, inflate() will |
| 369 | go ahead and process the first block, and will return when it gets to the end |
| 370 | of that block, or when it runs out of data. |
| 371 | |
| 372 | The Z_BLOCK option assists in appending to or combining deflate streams. |
| 373 | Also to assist in this, on return inflate() will set strm->data_type to the |
| 374 | number of unused bits in the last byte taken from strm->next_in, plus 64 |
| 375 | if inflate() is currently decoding the last block in the deflate stream, |
| 376 | plus 128 if inflate() returned immediately after decoding an end-of-block |
| 377 | code or decoding the complete header up to just before the first byte of the |
| 378 | deflate stream. The end-of-block will not be indicated until all of the |
| 379 | uncompressed data from that block has been written to strm->next_out. The |
| 380 | number of unused bits may in general be greater than seven, except when |
| 381 | bit 7 of data_type is set, in which case the number of unused bits will be |
| 382 | less than eight. |
| 383 | |
| 384 | inflate() should normally be called until it returns Z_STREAM_END or an |
| 385 | error. However if all decompression is to be performed in a single step |
| 386 | (a single call of inflate), the parameter flush should be set to |
| 387 | Z_FINISH. In this case all pending input is processed and all pending |
| 388 | output is flushed; avail_out must be large enough to hold all the |
| 389 | uncompressed data. (The size of the uncompressed data may have been saved |
| 390 | by the compressor for this purpose.) The next operation on this stream must |
| 391 | be inflateEnd to deallocate the decompression state. The use of Z_FINISH |
| 392 | is never required, but can be used to inform inflate that a faster approach |
| 393 | may be used for the single inflate() call. |
| 394 | |
| 395 | In this implementation, inflate() always flushes as much output as |
| 396 | possible to the output buffer, and always uses the faster approach on the |
| 397 | first call. So the only effect of the flush parameter in this implementation |
| 398 | is on the return value of inflate(), as noted below, or when it returns early |
| 399 | because Z_BLOCK is used. |
| 400 | |
| 401 | If a preset dictionary is needed after this call (see inflateSetDictionary |
| 402 | below), inflate sets strm->adler to the adler32 checksum of the dictionary |
| 403 | chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
| 404 | strm->adler to the adler32 checksum of all output produced so far (that is, |
| 405 | total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described |
| 406 | below. At the end of the stream, inflate() checks that its computed adler32 |
| 407 | checksum is equal to that saved by the compressor and returns Z_STREAM_END |
| 408 | only if the checksum is correct. |
| 409 | |
| 410 | inflate() will decompress and check either zlib-wrapped or gzip-wrapped |
| 411 | deflate data. The header type is detected automatically. Any information |
| 412 | contained in the gzip header is not retained, so applications that need that |
| 413 | information should instead use raw inflate, see inflateInit2() below, or |
| 414 | inflateBack() and perform their own processing of the gzip header and |
| 415 | trailer. |
| 416 | |
| 417 | inflate() returns Z_OK if some progress has been made (more input processed |
| 418 | or more output produced), Z_STREAM_END if the end of the compressed data has |
| 419 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
| 420 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
| 421 | corrupted (input stream not conforming to the zlib format or incorrect check |
| 422 | value), Z_STREAM_ERROR if the stream structure was inconsistent (for example |
| 423 | if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, |
| 424 | Z_BUF_ERROR if no progress is possible or if there was not enough room in the |
| 425 | output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
| 426 | inflate() can be called again with more input and more output space to |
| 427 | continue decompressing. If Z_DATA_ERROR is returned, the application may then |
| 428 | call inflateSync() to look for a good compression block if a partial recovery |
| 429 | of the data is desired. |
| 430 | */ |
| 431 | |
| 432 | |
| 433 | ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); |
| 434 | /* |
| 435 | All dynamically allocated data structures for this stream are freed. |
| 436 | This function discards any unprocessed input and does not flush any |
| 437 | pending output. |
| 438 | |
| 439 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
| 440 | was inconsistent. In the error case, msg may be set but then points to a |
| 441 | static string (which must not be deallocated). |
| 442 | */ |
| 443 | |
| 444 | /* Advanced functions */ |
| 445 | |
| 446 | /* |
| 447 | The following functions are needed only in some special applications. |
| 448 | */ |
| 449 | |
| 450 | /* |
| 451 | ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, |
| 452 | int level, |
| 453 | int method, |
| 454 | int windowBits, |
| 455 | int memLevel, |
| 456 | int strategy)); |
| 457 | |
| 458 | This is another version of deflateInit with more compression options. The |
| 459 | fields next_in, zalloc, zfree and opaque must be initialized before by |
| 460 | the caller. |
| 461 | |
| 462 | The method parameter is the compression method. It must be Z_DEFLATED in |
| 463 | this version of the library. |
| 464 | |
| 465 | The windowBits parameter is the base two logarithm of the window size |
| 466 | (the size of the history buffer). It should be in the range 8..15 for this |
| 467 | version of the library. Larger values of this parameter result in better |
| 468 | compression at the expense of memory usage. The default value is 15 if |
| 469 | deflateInit is used instead. |
| 470 | |
| 471 | windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
| 472 | determines the window size. deflate() will then generate raw deflate data |
| 473 | with no zlib header or trailer, and will not compute an adler32 check value. |
| 474 | |
| 475 | windowBits can also be greater than 15 for optional gzip encoding. Add |
| 476 | 16 to windowBits to write a simple gzip header and trailer around the |
| 477 | compressed data instead of a zlib wrapper. The gzip header will have no |
| 478 | file name, no extra data, no comment, no modification time (set to zero), |
| 479 | no header crc, and the operating system will be set to 255 (unknown). If a |
| 480 | gzip stream is being written, strm->adler is a crc32 instead of an adler32. |
| 481 | |
| 482 | The memLevel parameter specifies how much memory should be allocated |
| 483 | for the internal compression state. memLevel=1 uses minimum memory but |
| 484 | is slow and reduces compression ratio; memLevel=9 uses maximum memory |
| 485 | for optimal speed. The default value is 8. See zconf.h for total memory |
| 486 | usage as a function of windowBits and memLevel. |
| 487 | |
| 488 | The strategy parameter is used to tune the compression algorithm. Use the |
| 489 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
| 490 | filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no |
| 491 | string match), or Z_RLE to limit match distances to one (run-length |
| 492 | encoding). Filtered data consists mostly of small values with a somewhat |
| 493 | random distribution. In this case, the compression algorithm is tuned to |
| 494 | compress them better. The effect of Z_FILTERED is to force more Huffman |
| 495 | coding and less string matching; it is somewhat intermediate between |
| 496 | Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as |
| 497 | Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy |
| 498 | parameter only affects the compression ratio but not the correctness of the |
| 499 | compressed output even if it is not set appropriately. |
| 500 | |
| 501 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 502 | memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
| 503 | method). msg is set to null if there is no error message. deflateInit2 does |
| 504 | not perform any compression: this will be done by deflate(). |
| 505 | */ |
| 506 | |
| 507 | ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
| 508 | const Bytef *dictionary, |
| 509 | uInt dictLength)); |
| 510 | /* |
| 511 | Initializes the compression dictionary from the given byte sequence |
| 512 | without producing any compressed output. This function must be called |
| 513 | immediately after deflateInit, deflateInit2 or deflateReset, before any |
| 514 | call of deflate. The compressor and decompressor must use exactly the same |
| 515 | dictionary (see inflateSetDictionary). |
| 516 | |
| 517 | The dictionary should consist of strings (byte sequences) that are likely |
| 518 | to be encountered later in the data to be compressed, with the most commonly |
| 519 | used strings preferably put towards the end of the dictionary. Using a |
| 520 | dictionary is most useful when the data to be compressed is short and can be |
| 521 | predicted with good accuracy; the data can then be compressed better than |
| 522 | with the default empty dictionary. |
| 523 | |
| 524 | Depending on the size of the compression data structures selected by |
| 525 | deflateInit or deflateInit2, a part of the dictionary may in effect be |
| 526 | discarded, for example if the dictionary is larger than the window size in |
| 527 | deflate or deflate2. Thus the strings most likely to be useful should be |
| 528 | put at the end of the dictionary, not at the front. |
| 529 | |
| 530 | Upon return of this function, strm->adler is set to the adler32 value |
| 531 | of the dictionary; the decompressor may later use this value to determine |
| 532 | which dictionary has been used by the compressor. (The adler32 value |
| 533 | applies to the whole dictionary even if only a subset of the dictionary is |
| 534 | actually used by the compressor.) If a raw deflate was requested, then the |
| 535 | adler32 value is not computed and strm->adler is not set. |
| 536 | |
| 537 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
| 538 | parameter is invalid (such as NULL dictionary) or the stream state is |
| 539 | inconsistent (for example if deflate has already been called for this stream |
| 540 | or if the compression method is bsort). deflateSetDictionary does not |
| 541 | perform any compression: this will be done by deflate(). |
| 542 | */ |
| 543 | |
| 544 | ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, |
| 545 | z_streamp source)); |
| 546 | /* |
| 547 | Sets the destination stream as a complete copy of the source stream. |
| 548 | |
| 549 | This function can be useful when several compression strategies will be |
| 550 | tried, for example when there are several ways of pre-processing the input |
| 551 | data with a filter. The streams that will be discarded should then be freed |
| 552 | by calling deflateEnd. Note that deflateCopy duplicates the internal |
| 553 | compression state which can be quite large, so this strategy is slow and |
| 554 | can consume lots of memory. |
| 555 | |
| 556 | deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
| 557 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
| 558 | (such as zalloc being NULL). msg is left unchanged in both source and |
| 559 | destination. |
| 560 | */ |
| 561 | |
| 562 | ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); |
| 563 | /* |
| 564 | This function is equivalent to deflateEnd followed by deflateInit, |
| 565 | but does not free and reallocate all the internal compression state. |
| 566 | The stream will keep the same compression level and any other attributes |
| 567 | that may have been set by deflateInit2. |
| 568 | |
| 569 | deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 570 | stream state was inconsistent (such as zalloc or state being NULL). |
| 571 | */ |
| 572 | |
| 573 | ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, |
| 574 | int level, |
| 575 | int strategy)); |
| 576 | /* |
| 577 | Dynamically update the compression level and compression strategy. The |
| 578 | interpretation of level and strategy is as in deflateInit2. This can be |
| 579 | used to switch between compression and straight copy of the input data, or |
| 580 | to switch to a different kind of input data requiring a different |
| 581 | strategy. If the compression level is changed, the input available so far |
| 582 | is compressed with the old level (and may be flushed); the new level will |
| 583 | take effect only at the next call of deflate(). |
| 584 | |
| 585 | Before the call of deflateParams, the stream state must be set as for |
| 586 | a call of deflate(), since the currently available input may have to |
| 587 | be compressed and flushed. In particular, strm->avail_out must be non-zero. |
| 588 | |
| 589 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
| 590 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR |
| 591 | if strm->avail_out was zero. |
| 592 | */ |
| 593 | |
| 594 | ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, |
| 595 | uLong sourceLen)); |
| 596 | /* |
| 597 | deflateBound() returns an upper bound on the compressed size after |
| 598 | deflation of sourceLen bytes. It must be called after deflateInit() |
| 599 | or deflateInit2(). This would be used to allocate an output buffer |
| 600 | for deflation in a single pass, and so would be called before deflate(). |
| 601 | */ |
| 602 | |
| 603 | ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, |
| 604 | int bits, |
| 605 | int value)); |
| 606 | /* |
| 607 | deflatePrime() inserts bits in the deflate output stream. The intent |
| 608 | is that this function is used to start off the deflate output with the |
| 609 | bits leftover from a previous deflate stream when appending to it. As such, |
| 610 | this function can only be used for raw deflate, and must be used before the |
| 611 | first deflate() call after a deflateInit2() or deflateReset(). bits must be |
| 612 | less than or equal to 16, and that many of the least significant bits of |
| 613 | value will be inserted in the output. |
| 614 | |
| 615 | deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 616 | stream state was inconsistent. |
| 617 | */ |
| 618 | |
| 619 | /* |
| 620 | ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
| 621 | int windowBits)); |
| 622 | |
| 623 | This is another version of inflateInit with an extra parameter. The |
| 624 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
| 625 | before by the caller. |
| 626 | |
| 627 | The windowBits parameter is the base two logarithm of the maximum window |
| 628 | size (the size of the history buffer). It should be in the range 8..15 for |
| 629 | this version of the library. The default value is 15 if inflateInit is used |
| 630 | instead. windowBits must be greater than or equal to the windowBits value |
| 631 | provided to deflateInit2() while compressing, or it must be equal to 15 if |
| 632 | deflateInit2() was not used. If a compressed stream with a larger window |
| 633 | size is given as input, inflate() will return with the error code |
| 634 | Z_DATA_ERROR instead of trying to allocate a larger window. |
| 635 | |
| 636 | windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
| 637 | determines the window size. inflate() will then process raw deflate data, |
| 638 | not looking for a zlib or gzip header, not generating a check value, and not |
| 639 | looking for any check values for comparison at the end of the stream. This |
| 640 | is for use with other formats that use the deflate compressed data format |
| 641 | such as zip. Those formats provide their own check values. If a custom |
| 642 | format is developed using the raw deflate format for compressed data, it is |
| 643 | recommended that a check value such as an adler32 or a crc32 be applied to |
| 644 | the uncompressed data as is done in the zlib, gzip, and zip formats. For |
| 645 | most applications, the zlib format should be used as is. Note that comments |
| 646 | above on the use in deflateInit2() applies to the magnitude of windowBits. |
| 647 | |
| 648 | windowBits can also be greater than 15 for optional gzip decoding. Add |
| 649 | 32 to windowBits to enable zlib and gzip decoding with automatic header |
| 650 | detection, or add 16 to decode only the gzip format (the zlib format will |
| 651 | return a Z_DATA_ERROR. If a gzip stream is being decoded, strm->adler is |
| 652 | a crc32 instead of an adler32. |
| 653 | |
| 654 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 655 | memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative |
| 656 | memLevel). msg is set to null if there is no error message. inflateInit2 |
| 657 | does not perform any decompression apart from reading the zlib header if |
| 658 | present: this will be done by inflate(). (So next_in and avail_in may be |
| 659 | modified, but next_out and avail_out are unchanged.) |
| 660 | */ |
| 661 | |
| 662 | ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, |
| 663 | const Bytef *dictionary, |
| 664 | uInt dictLength)); |
| 665 | /* |
| 666 | Initializes the decompression dictionary from the given uncompressed byte |
| 667 | sequence. This function must be called immediately after a call of inflate |
| 668 | if this call returned Z_NEED_DICT. The dictionary chosen by the compressor |
| 669 | can be determined from the adler32 value returned by this call of |
| 670 | inflate. The compressor and decompressor must use exactly the same |
| 671 | dictionary (see deflateSetDictionary). |
| 672 | |
| 673 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
| 674 | parameter is invalid (such as NULL dictionary) or the stream state is |
| 675 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
| 676 | expected one (incorrect adler32 value). inflateSetDictionary does not |
| 677 | perform any decompression: this will be done by subsequent calls of |
| 678 | inflate(). |
| 679 | */ |
| 680 | |
| 681 | ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); |
| 682 | /* |
| 683 | Skips invalid compressed data until a full flush point (see above the |
| 684 | description of deflate with Z_FULL_FLUSH) can be found, or until all |
| 685 | available input is skipped. No output is provided. |
| 686 | |
| 687 | inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
| 688 | if no more input was provided, Z_DATA_ERROR if no flush point has been found, |
| 689 | or Z_STREAM_ERROR if the stream structure was inconsistent. In the success |
| 690 | case, the application may save the current current value of total_in which |
| 691 | indicates where valid compressed data was found. In the error case, the |
| 692 | application may repeatedly call inflateSync, providing more input each time, |
| 693 | until success or end of the input data. |
| 694 | */ |
| 695 | |
| 696 | ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, |
| 697 | z_streamp source)); |
| 698 | /* |
| 699 | Sets the destination stream as a complete copy of the source stream. |
| 700 | |
| 701 | This function can be useful when randomly accessing a large stream. The |
| 702 | first pass through the stream can periodically record the inflate state, |
| 703 | allowing restarting inflate at those points when randomly accessing the |
| 704 | stream. |
| 705 | |
| 706 | inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
| 707 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
| 708 | (such as zalloc being NULL). msg is left unchanged in both source and |
| 709 | destination. |
| 710 | */ |
| 711 | |
| 712 | ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); |
| 713 | /* |
| 714 | This function is equivalent to inflateEnd followed by inflateInit, |
| 715 | but does not free and reallocate all the internal decompression state. |
| 716 | The stream will keep attributes that may have been set by inflateInit2. |
| 717 | |
| 718 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 719 | stream state was inconsistent (such as zalloc or state being NULL). |
| 720 | */ |
| 721 | |
| 722 | /* |
| 723 | ZEXTERN int ZEXPORT inflateBackInit OF((z_stream FAR *strm, int windowBits, |
| 724 | unsigned char FAR *window)); |
| 725 | |
| 726 | Initialize the internal stream state for decompression using inflateBack() |
| 727 | calls. The fields zalloc, zfree and opaque in strm must be initialized |
| 728 | before the call. If zalloc and zfree are Z_NULL, then the default library- |
| 729 | derived memory allocation routines are used. windowBits is the base two |
| 730 | logarithm of the window size, in the range 8..15. window is a caller |
| 731 | supplied buffer of that size. Except for special applications where it is |
| 732 | assured that deflate was used with small window sizes, windowBits must be 15 |
| 733 | and a 32K byte window must be supplied to be able to decompress general |
| 734 | deflate streams. |
| 735 | |
| 736 | See inflateBack() for the usage of these routines. |
| 737 | |
| 738 | inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of |
| 739 | the paramaters are invalid, Z_MEM_ERROR if the internal state could not |
| 740 | be allocated, or Z_VERSION_ERROR if the version of the library does not |
| 741 | match the version of the header file. |
| 742 | */ |
| 743 | |
| 744 | typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); |
| 745 | typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); |
| 746 | |
| 747 | ZEXTERN int ZEXPORT inflateBack OF((z_stream FAR *strm, |
| 748 | in_func in, void FAR *in_desc, |
| 749 | out_func out, void FAR *out_desc)); |
| 750 | /* |
| 751 | inflateBack() does a raw inflate with a single call using a call-back |
| 752 | interface for input and output. This is more efficient than inflate() for |
| 753 | file i/o applications in that it avoids copying between the output and the |
| 754 | sliding window by simply making the window itself the output buffer. This |
| 755 | function trusts the application to not change the output buffer passed by |
| 756 | the output function, at least until inflateBack() returns. |
| 757 | |
| 758 | inflateBackInit() must be called first to allocate the internal state |
| 759 | and to initialize the state with the user-provided window buffer. |
| 760 | inflateBack() may then be used multiple times to inflate a complete, raw |
| 761 | deflate stream with each call. inflateBackEnd() is then called to free |
| 762 | the allocated state. |
| 763 | |
| 764 | A raw deflate stream is one with no zlib or gzip header or trailer. |
| 765 | This routine would normally be used in a utility that reads zip or gzip |
| 766 | files and writes out uncompressed files. The utility would decode the |
| 767 | header and process the trailer on its own, hence this routine expects |
| 768 | only the raw deflate stream to decompress. This is different from the |
| 769 | normal behavior of inflate(), which expects either a zlib or gzip header and |
| 770 | trailer around the deflate stream. |
| 771 | |
| 772 | inflateBack() uses two subroutines supplied by the caller that are then |
| 773 | called by inflateBack() for input and output. inflateBack() calls those |
| 774 | routines until it reads a complete deflate stream and writes out all of the |
| 775 | uncompressed data, or until it encounters an error. The function's |
| 776 | parameters and return types are defined above in the in_func and out_func |
| 777 | typedefs. inflateBack() will call in(in_desc, &buf) which should return the |
| 778 | number of bytes of provided input, and a pointer to that input in buf. If |
| 779 | there is no input available, in() must return zero--buf is ignored in that |
| 780 | case--and inflateBack() will return a buffer error. inflateBack() will call |
| 781 | out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() |
| 782 | should return zero on success, or non-zero on failure. If out() returns |
| 783 | non-zero, inflateBack() will return with an error. Neither in() nor out() |
| 784 | are permitted to change the contents of the window provided to |
| 785 | inflateBackInit(), which is also the buffer that out() uses to write from. |
| 786 | The length written by out() will be at most the window size. Any non-zero |
| 787 | amount of input may be provided by in(). |
| 788 | |
| 789 | For convenience, inflateBack() can be provided input on the first call by |
| 790 | setting strm->next_in and strm->avail_in. If that input is exhausted, then |
| 791 | in() will be called. Therefore strm->next_in must be initialized before |
| 792 | calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called |
| 793 | immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in |
| 794 | must also be initialized, and then if strm->avail_in is not zero, input will |
| 795 | initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
| 796 | |
| 797 | The in_desc and out_desc parameters of inflateBack() is passed as the |
| 798 | first parameter of in() and out() respectively when they are called. These |
| 799 | descriptors can be optionally used to pass any information that the caller- |
| 800 | supplied in() and out() functions need to do their job. |
| 801 | |
| 802 | On return, inflateBack() will set strm->next_in and strm->avail_in to |
| 803 | pass back any unused input that was provided by the last in() call. The |
| 804 | return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR |
| 805 | if in() or out() returned an error, Z_DATA_ERROR if there was a format |
| 806 | error in the deflate stream (in which case strm->msg is set to indicate the |
| 807 | nature of the error), or Z_STREAM_ERROR if the stream was not properly |
| 808 | initialized. In the case of Z_BUF_ERROR, an input or output error can be |
| 809 | distinguished using strm->next_in which will be Z_NULL only if in() returned |
| 810 | an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to |
| 811 | out() returning non-zero. (in() will always be called before out(), so |
| 812 | strm->next_in is assured to be defined if out() returns non-zero.) Note |
| 813 | that inflateBack() cannot return Z_OK. |
| 814 | */ |
| 815 | |
| 816 | ZEXTERN int ZEXPORT inflateBackEnd OF((z_stream FAR *strm)); |
| 817 | /* |
| 818 | All memory allocated by inflateBackInit() is freed. |
| 819 | |
| 820 | inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream |
| 821 | state was inconsistent. |
| 822 | */ |
| 823 | |
| 824 | ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); |
| 825 | /* Return flags indicating compile-time options. |
| 826 | |
| 827 | Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: |
| 828 | 1.0: size of uInt |
| 829 | 3.2: size of uLong |
| 830 | 5.4: size of voidpf (pointer) |
| 831 | 7.6: size of z_off_t |
| 832 | |
| 833 | Compiler, assembler, and debug options: |
| 834 | 8: DEBUG |
| 835 | 9: ASMV or ASMINF -- use ASM code |
| 836 | 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention |
| 837 | 11: 0 (reserved) |
| 838 | |
| 839 | One-time table building (smaller code, but not thread-safe if true): |
| 840 | 12: BUILDFIXED -- build static block decoding tables when needed |
| 841 | 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed |
| 842 | 14,15: 0 (reserved) |
| 843 | |
| 844 | Library content (indicates missing functionality): |
| 845 | 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking |
| 846 | deflate code when not needed) |
| 847 | 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect |
| 848 | and decode gzip streams (to avoid linking crc code) |
| 849 | 18-19: 0 (reserved) |
| 850 | |
| 851 | Operation variations (changes in library functionality): |
| 852 | 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate |
| 853 | 21: FASTEST -- deflate algorithm with only one, lowest compression level |
| 854 | 22,23: 0 (reserved) |
| 855 | |
| 856 | The sprintf variant used by gzprintf (zero is best): |
| 857 | 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format |
| 858 | 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! |
| 859 | 26: 0 = returns value, 1 = void -- 1 means inferred string length returned |
| 860 | |
| 861 | Remainder: |
| 862 | 27-31: 0 (reserved) |
| 863 | */ |
| 864 | |
| 865 | |
| 866 | /* utility functions */ |
| 867 | |
| 868 | /* |
| 869 | The following utility functions are implemented on top of the |
| 870 | basic stream-oriented functions. To simplify the interface, some |
| 871 | default options are assumed (compression level and memory usage, |
| 872 | standard memory allocation functions). The source code of these |
| 873 | utility functions can easily be modified if you need special options. |
| 874 | */ |
| 875 | |
| 876 | ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, |
| 877 | const Bytef *source, uLong sourceLen)); |
| 878 | /* |
| 879 | Compresses the source buffer into the destination buffer. sourceLen is |
| 880 | the byte length of the source buffer. Upon entry, destLen is the total |
| 881 | size of the destination buffer, which must be at least the value returned |
| 882 | by compressBound(sourceLen). Upon exit, destLen is the actual size of the |
| 883 | compressed buffer. |
| 884 | This function can be used to compress a whole file at once if the |
| 885 | input file is mmap'ed. |
| 886 | compress returns Z_OK if success, Z_MEM_ERROR if there was not |
| 887 | enough memory, Z_BUF_ERROR if there was not enough room in the output |
| 888 | buffer. |
| 889 | */ |
| 890 | |
| 891 | ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, |
| 892 | const Bytef *source, uLong sourceLen, |
| 893 | int level)); |
| 894 | /* |
| 895 | Compresses the source buffer into the destination buffer. The level |
| 896 | parameter has the same meaning as in deflateInit. sourceLen is the byte |
| 897 | length of the source buffer. Upon entry, destLen is the total size of the |
| 898 | destination buffer, which must be at least the value returned by |
| 899 | compressBound(sourceLen). Upon exit, destLen is the actual size of the |
| 900 | compressed buffer. |
| 901 | |
| 902 | compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 903 | memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
| 904 | Z_STREAM_ERROR if the level parameter is invalid. |
| 905 | */ |
| 906 | |
| 907 | ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); |
| 908 | /* |
| 909 | compressBound() returns an upper bound on the compressed size after |
| 910 | compress() or compress2() on sourceLen bytes. It would be used before |
| 911 | a compress() or compress2() call to allocate the destination buffer. |
| 912 | */ |
| 913 | |
| 914 | ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, |
| 915 | const Bytef *source, uLong sourceLen)); |
| 916 | /* |
| 917 | Decompresses the source buffer into the destination buffer. sourceLen is |
| 918 | the byte length of the source buffer. Upon entry, destLen is the total |
| 919 | size of the destination buffer, which must be large enough to hold the |
| 920 | entire uncompressed data. (The size of the uncompressed data must have |
| 921 | been saved previously by the compressor and transmitted to the decompressor |
| 922 | by some mechanism outside the scope of this compression library.) |
| 923 | Upon exit, destLen is the actual size of the compressed buffer. |
| 924 | This function can be used to decompress a whole file at once if the |
| 925 | input file is mmap'ed. |
| 926 | |
| 927 | uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
| 928 | enough memory, Z_BUF_ERROR if there was not enough room in the output |
| 929 | buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. |
| 930 | */ |
| 931 | |
| 932 | |
| 933 | typedef voidp gzFile; |
| 934 | |
| 935 | ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
| 936 | /* |
| 937 | Opens a gzip (.gz) file for reading or writing. The mode parameter |
| 938 | is as in fopen ("rb" or "wb") but can also include a compression level |
| 939 | ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for |
| 940 | Huffman only compression as in "wb1h", or 'R' for run-length encoding |
| 941 | as in "wb1R". (See the description of deflateInit2 for more information |
| 942 | about the strategy parameter.) |
| 943 | |
| 944 | gzopen can be used to read a file which is not in gzip format; in this |
| 945 | case gzread will directly read from the file without decompression. |
| 946 | |
| 947 | gzopen returns NULL if the file could not be opened or if there was |
| 948 | insufficient memory to allocate the (de)compression state; errno |
| 949 | can be checked to distinguish the two cases (if errno is zero, the |
| 950 | zlib error is Z_MEM_ERROR). */ |
| 951 | |
| 952 | ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
| 953 | /* |
| 954 | gzdopen() associates a gzFile with the file descriptor fd. File |
| 955 | descriptors are obtained from calls like open, dup, creat, pipe or |
| 956 | fileno (in the file has been previously opened with fopen). |
| 957 | The mode parameter is as in gzopen. |
| 958 | The next call of gzclose on the returned gzFile will also close the |
| 959 | file descriptor fd, just like fclose(fdopen(fd), mode) closes the file |
| 960 | descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). |
| 961 | gzdopen returns NULL if there was insufficient memory to allocate |
| 962 | the (de)compression state. |
| 963 | */ |
| 964 | |
| 965 | ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); |
| 966 | /* |
| 967 | Dynamically update the compression level or strategy. See the description |
| 968 | of deflateInit2 for the meaning of these parameters. |
| 969 | gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
| 970 | opened for writing. |
| 971 | */ |
| 972 | |
| 973 | ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
| 974 | /* |
| 975 | Reads the given number of uncompressed bytes from the compressed file. |
| 976 | If the input file was not in gzip format, gzread copies the given number |
| 977 | of bytes into the buffer. |
| 978 | gzread returns the number of uncompressed bytes actually read (0 for |
| 979 | end of file, -1 for error). */ |
| 980 | |
| 981 | ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
| 982 | voidpc buf, unsigned len)); |
| 983 | /* |
| 984 | Writes the given number of uncompressed bytes into the compressed file. |
| 985 | gzwrite returns the number of uncompressed bytes actually written |
| 986 | (0 in case of error). |
| 987 | */ |
| 988 | |
| 989 | ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
| 990 | /* |
| 991 | Converts, formats, and writes the args to the compressed file under |
| 992 | control of the format string, as in fprintf. gzprintf returns the number of |
| 993 | uncompressed bytes actually written (0 in case of error). The number of |
| 994 | uncompressed bytes written is limited to 4095. The caller should assure that |
| 995 | this limit is not exceeded. If it is exceeded, then gzprintf() will return |
| 996 | return an error (0) with nothing written. In this case, there may also be a |
| 997 | buffer overflow with unpredictable consequences, which is possible only if |
| 998 | zlib was compiled with the insecure functions sprintf() or vsprintf() |
| 999 | because the secure snprintf() or vsnprintf() functions were not available. |
| 1000 | */ |
| 1001 | |
| 1002 | ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); |
| 1003 | /* |
| 1004 | Writes the given null-terminated string to the compressed file, excluding |
| 1005 | the terminating null character. |
| 1006 | gzputs returns the number of characters written, or -1 in case of error. |
| 1007 | */ |
| 1008 | |
| 1009 | ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); |
| 1010 | /* |
| 1011 | Reads bytes from the compressed file until len-1 characters are read, or |
| 1012 | a newline character is read and transferred to buf, or an end-of-file |
| 1013 | condition is encountered. The string is then terminated with a null |
| 1014 | character. |
| 1015 | gzgets returns buf, or Z_NULL in case of error. |
| 1016 | */ |
| 1017 | |
| 1018 | ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
| 1019 | /* |
| 1020 | Writes c, converted to an unsigned char, into the compressed file. |
| 1021 | gzputc returns the value that was written, or -1 in case of error. |
| 1022 | */ |
| 1023 | |
| 1024 | ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
| 1025 | /* |
| 1026 | Reads one byte from the compressed file. gzgetc returns this byte |
| 1027 | or -1 in case of end of file or error. |
| 1028 | */ |
| 1029 | |
| 1030 | ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); |
| 1031 | /* |
| 1032 | Push one character back onto the stream to be read again later. |
| 1033 | Only one character of push-back is allowed. gzungetc() returns the |
| 1034 | character pushed, or -1 on failure. gzungetc() will fail if a |
| 1035 | character has been pushed but not read yet, or if c is -1. The pushed |
| 1036 | character will be discarded if the stream is repositioned with gzseek() |
| 1037 | or gzrewind(). |
| 1038 | */ |
| 1039 | |
| 1040 | ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
| 1041 | /* |
| 1042 | Flushes all pending output into the compressed file. The parameter |
| 1043 | flush is as in the deflate() function. The return value is the zlib |
| 1044 | error number (see function gzerror below). gzflush returns Z_OK if |
| 1045 | the flush parameter is Z_FINISH and all output could be flushed. |
| 1046 | gzflush should be called only when strictly necessary because it can |
| 1047 | degrade compression. |
| 1048 | */ |
| 1049 | |
| 1050 | ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
| 1051 | z_off_t offset, int whence)); |
| 1052 | /* |
| 1053 | Sets the starting position for the next gzread or gzwrite on the |
| 1054 | given compressed file. The offset represents a number of bytes in the |
| 1055 | uncompressed data stream. The whence parameter is defined as in lseek(2); |
| 1056 | the value SEEK_END is not supported. |
| 1057 | If the file is opened for reading, this function is emulated but can be |
| 1058 | extremely slow. If the file is opened for writing, only forward seeks are |
| 1059 | supported; gzseek then compresses a sequence of zeroes up to the new |
| 1060 | starting position. |
| 1061 | |
| 1062 | gzseek returns the resulting offset location as measured in bytes from |
| 1063 | the beginning of the uncompressed stream, or -1 in case of error, in |
| 1064 | particular if the file is opened for writing and the new starting position |
| 1065 | would be before the current position. |
| 1066 | */ |
| 1067 | |
| 1068 | ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); |
| 1069 | /* |
| 1070 | Rewinds the given file. This function is supported only for reading. |
| 1071 | |
| 1072 | gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
| 1073 | */ |
| 1074 | |
| 1075 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
| 1076 | /* |
| 1077 | Returns the starting position for the next gzread or gzwrite on the |
| 1078 | given compressed file. This position represents a number of bytes in the |
| 1079 | uncompressed data stream. |
| 1080 | |
| 1081 | gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
| 1082 | */ |
| 1083 | |
| 1084 | ZEXTERN int ZEXPORT gzeof OF((gzFile file)); |
| 1085 | /* |
| 1086 | Returns 1 when EOF has previously been detected reading the given |
| 1087 | input stream, otherwise zero. |
| 1088 | */ |
| 1089 | |
| 1090 | ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
| 1091 | /* |
| 1092 | Flushes all pending output if necessary, closes the compressed file |
| 1093 | and deallocates all the (de)compression state. The return value is the zlib |
| 1094 | error number (see function gzerror below). |
| 1095 | */ |
| 1096 | |
| 1097 | ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); |
| 1098 | /* |
| 1099 | Returns the error message for the last error which occurred on the |
| 1100 | given compressed file. errnum is set to zlib error number. If an |
| 1101 | error occurred in the file system and not in the compression library, |
| 1102 | errnum is set to Z_ERRNO and the application may consult errno |
| 1103 | to get the exact error code. |
| 1104 | */ |
| 1105 | |
| 1106 | ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); |
| 1107 | /* |
| 1108 | Clears the error and end-of-file flags for file. This is analogous to the |
| 1109 | clearerr() function in stdio. This is useful for continuing to read a gzip |
| 1110 | file that is being written concurrently. |
| 1111 | */ |
| 1112 | |
| 1113 | /* checksum functions */ |
| 1114 | |
| 1115 | /* |
| 1116 | These functions are not related to compression but are exported |
| 1117 | anyway because they might be useful in applications using the |
| 1118 | compression library. |
| 1119 | */ |
| 1120 | |
| 1121 | ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
| 1122 | |
| 1123 | /* |
| 1124 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
| 1125 | return the updated checksum. If buf is NULL, this function returns |
| 1126 | the required initial value for the checksum. |
| 1127 | An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
| 1128 | much faster. Usage example: |
| 1129 | |
| 1130 | uLong adler = adler32(0L, Z_NULL, 0); |
| 1131 | |
| 1132 | while (read_buffer(buffer, length) != EOF) { |
| 1133 | adler = adler32(adler, buffer, length); |
| 1134 | } |
| 1135 | if (adler != original_adler) error(); |
| 1136 | */ |
| 1137 | |
| 1138 | ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
| 1139 | /* |
| 1140 | Update a running crc with the bytes buf[0..len-1] and return the updated |
| 1141 | crc. If buf is NULL, this function returns the required initial value |
| 1142 | for the crc. Pre- and post-conditioning (one's complement) is performed |
| 1143 | within this function so it shouldn't be done by the application. |
| 1144 | Usage example: |
| 1145 | |
| 1146 | uLong crc = crc32(0L, Z_NULL, 0); |
| 1147 | |
| 1148 | while (read_buffer(buffer, length) != EOF) { |
| 1149 | crc = crc32(crc, buffer, length); |
| 1150 | } |
| 1151 | if (crc != original_crc) error(); |
| 1152 | */ |
| 1153 | |
| 1154 | |
| 1155 | /* various hacks, don't look :) */ |
| 1156 | |
| 1157 | /* deflateInit and inflateInit are macros to allow checking the zlib version |
| 1158 | * and the compiler's view of z_stream: |
| 1159 | */ |
| 1160 | ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, |
| 1161 | const char *version, int stream_size)); |
| 1162 | ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, |
| 1163 | const char *version, int stream_size)); |
| 1164 | ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, |
| 1165 | int windowBits, int memLevel, |
| 1166 | int strategy, const char *version, |
| 1167 | int stream_size)); |
| 1168 | ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, |
| 1169 | const char *version, int stream_size)); |
| 1170 | ZEXTERN int ZEXPORT inflateBackInit_ OF((z_stream FAR *strm, int windowBits, |
| 1171 | unsigned char FAR *window, |
| 1172 | const char *version, |
| 1173 | int stream_size)); |
| 1174 | #define deflateInit(strm, level) \ |
| 1175 | deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
| 1176 | #define inflateInit(strm) \ |
| 1177 | inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
| 1178 | #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
| 1179 | deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
| 1180 | (strategy), ZLIB_VERSION, sizeof(z_stream)) |
| 1181 | #define inflateInit2(strm, windowBits) \ |
| 1182 | inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
| 1183 | #define inflateBackInit(strm, windowBits, window) \ |
| 1184 | inflateBackInit_((strm), (windowBits), (window), \ |
| 1185 | ZLIB_VERSION, sizeof(z_stream)) |
| 1186 | |
| 1187 | |
| 1188 | #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
| 1189 | struct internal_state {int dummy;}; /* hack for buggy compilers */ |
| 1190 | #endif |
| 1191 | |
| 1192 | ZEXTERN const char * ZEXPORT zError OF((int)); |
| 1193 | ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); |
| 1194 | ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
| 1195 | |
| 1196 | #ifdef __cplusplus |
| 1197 | } |
| 1198 | #endif |
| 1199 | |
| 1200 | #endif /* ZLIB_H */ |