Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
| 2 | version 1.1.3, July 9th, 1998 |
| 3 | |
| 4 | Copyright (C) 1995-1998 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 ftp://ds.internic.net/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 <linux/zconf.h> |
| 35 | |
| 36 | #define ZLIB_VERSION "1.1.3" |
| 37 | |
| 38 | /* |
| 39 | The 'zlib' compression library provides in-memory compression and |
| 40 | decompression functions, including integrity checks of the uncompressed |
| 41 | data. This version of the library supports only one compression method |
| 42 | (deflation) but other algorithms will be added later and will have the same |
| 43 | stream interface. |
| 44 | |
| 45 | Compression can be done in a single step if the buffers are large |
| 46 | enough (for example if an input file is mmap'ed), or can be done by |
| 47 | repeated calls of the compression function. In the latter case, the |
| 48 | application must provide more input and/or consume the output |
| 49 | (providing more output space) before each call. |
| 50 | |
| 51 | The library also supports reading and writing files in gzip (.gz) format |
| 52 | with an interface similar to that of stdio. |
| 53 | |
| 54 | The library does not install any signal handler. The decoder checks |
| 55 | the consistency of the compressed data, so the library should never |
| 56 | crash even in case of corrupted input. |
| 57 | */ |
| 58 | |
| 59 | struct internal_state; |
| 60 | |
| 61 | typedef struct z_stream_s { |
| 62 | Byte *next_in; /* next input byte */ |
| 63 | uInt avail_in; /* number of bytes available at next_in */ |
| 64 | uLong total_in; /* total nb of input bytes read so far */ |
| 65 | |
| 66 | Byte *next_out; /* next output byte should be put there */ |
| 67 | uInt avail_out; /* remaining free space at next_out */ |
| 68 | uLong total_out; /* total nb of bytes output so far */ |
| 69 | |
| 70 | char *msg; /* last error message, NULL if no error */ |
| 71 | struct internal_state *state; /* not visible by applications */ |
| 72 | |
| 73 | void *workspace; /* memory allocated for this stream */ |
| 74 | |
| 75 | int data_type; /* best guess about the data type: ascii or binary */ |
| 76 | uLong adler; /* adler32 value of the uncompressed data */ |
| 77 | uLong reserved; /* reserved for future use */ |
| 78 | } z_stream; |
| 79 | |
| 80 | typedef z_stream *z_streamp; |
| 81 | |
| 82 | /* |
| 83 | The application must update next_in and avail_in when avail_in has |
| 84 | dropped to zero. It must update next_out and avail_out when avail_out |
| 85 | has dropped to zero. The application must initialize zalloc, zfree and |
| 86 | opaque before calling the init function. All other fields are set by the |
| 87 | compression library and must not be updated by the application. |
| 88 | |
| 89 | The opaque value provided by the application will be passed as the first |
| 90 | parameter for calls of zalloc and zfree. This can be useful for custom |
| 91 | memory management. The compression library attaches no meaning to the |
| 92 | opaque value. |
| 93 | |
| 94 | zalloc must return NULL if there is not enough memory for the object. |
| 95 | If zlib is used in a multi-threaded application, zalloc and zfree must be |
| 96 | thread safe. |
| 97 | |
| 98 | On 16-bit systems, the functions zalloc and zfree must be able to allocate |
| 99 | exactly 65536 bytes, but will not be required to allocate more than this |
| 100 | if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, |
| 101 | pointers returned by zalloc for objects of exactly 65536 bytes *must* |
| 102 | have their offset normalized to zero. The default allocation function |
| 103 | provided by this library ensures this (see zutil.c). To reduce memory |
| 104 | requirements and avoid any allocation of 64K objects, at the expense of |
| 105 | compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). |
| 106 | |
| 107 | The fields total_in and total_out can be used for statistics or |
| 108 | progress reports. After compression, total_in holds the total size of |
| 109 | the uncompressed data and may be saved for use in the decompressor |
| 110 | (particularly if the decompressor wants to decompress everything in |
| 111 | a single step). |
| 112 | */ |
| 113 | |
| 114 | /* constants */ |
| 115 | |
| 116 | #define Z_NO_FLUSH 0 |
| 117 | #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ |
| 118 | #define Z_PACKET_FLUSH 2 |
| 119 | #define Z_SYNC_FLUSH 3 |
| 120 | #define Z_FULL_FLUSH 4 |
| 121 | #define Z_FINISH 5 |
| 122 | /* Allowed flush values; see deflate() below for details */ |
| 123 | |
| 124 | #define Z_OK 0 |
| 125 | #define Z_STREAM_END 1 |
| 126 | #define Z_NEED_DICT 2 |
| 127 | #define Z_ERRNO (-1) |
| 128 | #define Z_STREAM_ERROR (-2) |
| 129 | #define Z_DATA_ERROR (-3) |
| 130 | #define Z_MEM_ERROR (-4) |
| 131 | #define Z_BUF_ERROR (-5) |
| 132 | #define Z_VERSION_ERROR (-6) |
| 133 | /* Return codes for the compression/decompression functions. Negative |
| 134 | * values are errors, positive values are used for special but normal events. |
| 135 | */ |
| 136 | |
| 137 | #define Z_NO_COMPRESSION 0 |
| 138 | #define Z_BEST_SPEED 1 |
| 139 | #define Z_BEST_COMPRESSION 9 |
| 140 | #define Z_DEFAULT_COMPRESSION (-1) |
| 141 | /* compression levels */ |
| 142 | |
| 143 | #define Z_FILTERED 1 |
| 144 | #define Z_HUFFMAN_ONLY 2 |
| 145 | #define Z_DEFAULT_STRATEGY 0 |
| 146 | /* compression strategy; see deflateInit2() below for details */ |
| 147 | |
| 148 | #define Z_BINARY 0 |
| 149 | #define Z_ASCII 1 |
| 150 | #define Z_UNKNOWN 2 |
| 151 | /* Possible values of the data_type field */ |
| 152 | |
| 153 | #define Z_DEFLATED 8 |
| 154 | /* The deflate compression method (the only one supported in this version) */ |
| 155 | |
| 156 | /* basic functions */ |
| 157 | |
| 158 | extern const char * zlib_zlibVersion (void); |
| 159 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
| 160 | If the first character differs, the library code actually used is |
| 161 | not compatible with the zlib.h header file used by the application. |
| 162 | This check is automatically made by deflateInit and inflateInit. |
| 163 | */ |
| 164 | |
| 165 | extern int zlib_deflate_workspacesize (void); |
| 166 | /* |
| 167 | Returns the number of bytes that needs to be allocated for a per- |
| 168 | stream workspace. A pointer to this number of bytes should be |
| 169 | returned in stream->workspace before calling zlib_deflateInit(). |
| 170 | */ |
| 171 | |
| 172 | /* |
| 173 | extern int deflateInit (z_streamp strm, int level); |
| 174 | |
| 175 | Initializes the internal stream state for compression. The fields |
| 176 | zalloc, zfree and opaque must be initialized before by the caller. |
| 177 | If zalloc and zfree are set to NULL, deflateInit updates them to |
| 178 | use default allocation functions. |
| 179 | |
| 180 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
| 181 | 1 gives best speed, 9 gives best compression, 0 gives no compression at |
| 182 | all (the input data is simply copied a block at a time). |
| 183 | Z_DEFAULT_COMPRESSION requests a default compromise between speed and |
| 184 | compression (currently equivalent to level 6). |
| 185 | |
| 186 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
| 187 | enough memory, Z_STREAM_ERROR if level is not a valid compression level, |
| 188 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
| 189 | with the version assumed by the caller (ZLIB_VERSION). |
| 190 | msg is set to null if there is no error message. deflateInit does not |
| 191 | perform any compression: this will be done by deflate(). |
| 192 | */ |
| 193 | |
| 194 | |
| 195 | extern int zlib_deflate (z_streamp strm, int flush); |
| 196 | /* |
| 197 | deflate compresses as much data as possible, and stops when the input |
| 198 | buffer becomes empty or the output buffer becomes full. It may introduce some |
| 199 | output latency (reading input without producing any output) except when |
| 200 | forced to flush. |
| 201 | |
| 202 | The detailed semantics are as follows. deflate performs one or both of the |
| 203 | following actions: |
| 204 | |
| 205 | - Compress more input starting at next_in and update next_in and avail_in |
| 206 | accordingly. If not all input can be processed (because there is not |
| 207 | enough room in the output buffer), next_in and avail_in are updated and |
| 208 | processing will resume at this point for the next call of deflate(). |
| 209 | |
| 210 | - Provide more output starting at next_out and update next_out and avail_out |
| 211 | accordingly. This action is forced if the parameter flush is non zero. |
| 212 | Forcing flush frequently degrades the compression ratio, so this parameter |
| 213 | should be set only when necessary (in interactive applications). |
| 214 | Some output may be provided even if flush is not set. |
| 215 | |
| 216 | Before the call of deflate(), the application should ensure that at least |
| 217 | one of the actions is possible, by providing more input and/or consuming |
| 218 | more output, and updating avail_in or avail_out accordingly; avail_out |
| 219 | should never be zero before the call. The application can consume the |
| 220 | compressed output when it wants, for example when the output buffer is full |
| 221 | (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK |
| 222 | and with zero avail_out, it must be called again after making room in the |
| 223 | output buffer because there might be more output pending. |
| 224 | |
| 225 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
| 226 | flushed to the output buffer and the output is aligned on a byte boundary, so |
| 227 | that the decompressor can get all input data available so far. (In particular |
| 228 | avail_in is zero after the call if enough output space has been provided |
| 229 | before the call.) Flushing may degrade compression for some compression |
| 230 | algorithms and so it should be used only when necessary. |
| 231 | |
| 232 | If flush is set to Z_FULL_FLUSH, all output is flushed as with |
| 233 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
| 234 | restart from this point if previous compressed data has been damaged or if |
| 235 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
| 236 | the compression. |
| 237 | |
| 238 | If deflate returns with avail_out == 0, this function must be called again |
| 239 | with the same value of the flush parameter and more output space (updated |
| 240 | avail_out), until the flush is complete (deflate returns with non-zero |
| 241 | avail_out). |
| 242 | |
| 243 | If the parameter flush is set to Z_FINISH, pending input is processed, |
| 244 | pending output is flushed and deflate returns with Z_STREAM_END if there |
| 245 | was enough output space; if deflate returns with Z_OK, this function must be |
| 246 | called again with Z_FINISH and more output space (updated avail_out) but no |
| 247 | more input data, until it returns with Z_STREAM_END or an error. After |
| 248 | deflate has returned Z_STREAM_END, the only possible operations on the |
| 249 | stream are deflateReset or deflateEnd. |
| 250 | |
| 251 | Z_FINISH can be used immediately after deflateInit if all the compression |
| 252 | is to be done in a single step. In this case, avail_out must be at least |
| 253 | 0.1% larger than avail_in plus 12 bytes. If deflate does not return |
| 254 | Z_STREAM_END, then it must be called again as described above. |
| 255 | |
| 256 | deflate() sets strm->adler to the adler32 checksum of all input read |
| 257 | so far (that is, total_in bytes). |
| 258 | |
| 259 | deflate() may update data_type if it can make a good guess about |
| 260 | the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered |
| 261 | binary. This field is only for information purposes and does not affect |
| 262 | the compression algorithm in any manner. |
| 263 | |
| 264 | deflate() returns Z_OK if some progress has been made (more input |
| 265 | processed or more output produced), Z_STREAM_END if all input has been |
| 266 | consumed and all output has been produced (only when flush is set to |
| 267 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
| 268 | if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
| 269 | (for example avail_in or avail_out was zero). |
| 270 | */ |
| 271 | |
| 272 | |
| 273 | extern int zlib_deflateEnd (z_streamp strm); |
| 274 | /* |
| 275 | All dynamically allocated data structures for this stream are freed. |
| 276 | This function discards any unprocessed input and does not flush any |
| 277 | pending output. |
| 278 | |
| 279 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
| 280 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
| 281 | prematurely (some input or output was discarded). In the error case, |
| 282 | msg may be set but then points to a static string (which must not be |
| 283 | deallocated). |
| 284 | */ |
| 285 | |
| 286 | |
| 287 | extern int zlib_inflate_workspacesize (void); |
| 288 | /* |
| 289 | Returns the number of bytes that needs to be allocated for a per- |
| 290 | stream workspace. A pointer to this number of bytes should be |
| 291 | returned in stream->workspace before calling zlib_inflateInit(). |
| 292 | */ |
| 293 | |
| 294 | /* |
| 295 | extern int zlib_inflateInit (z_streamp strm); |
| 296 | |
| 297 | Initializes the internal stream state for decompression. The fields |
| 298 | next_in, avail_in, and workspace must be initialized before by |
| 299 | the caller. If next_in is not NULL and avail_in is large enough (the exact |
| 300 | value depends on the compression method), inflateInit determines the |
| 301 | compression method from the zlib header and allocates all data structures |
| 302 | accordingly; otherwise the allocation will be deferred to the first call of |
| 303 | inflate. If zalloc and zfree are set to NULL, inflateInit updates them to |
| 304 | use default allocation functions. |
| 305 | |
| 306 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 307 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
| 308 | version assumed by the caller. msg is set to null if there is no error |
| 309 | message. inflateInit does not perform any decompression apart from reading |
| 310 | the zlib header if present: this will be done by inflate(). (So next_in and |
| 311 | avail_in may be modified, but next_out and avail_out are unchanged.) |
| 312 | */ |
| 313 | |
| 314 | |
| 315 | extern int zlib_inflate (z_streamp strm, int flush); |
| 316 | /* |
| 317 | inflate decompresses as much data as possible, and stops when the input |
| 318 | buffer becomes empty or the output buffer becomes full. It may some |
| 319 | introduce some output latency (reading input without producing any output) |
| 320 | except when forced to flush. |
| 321 | |
| 322 | The detailed semantics are as follows. inflate performs one or both of the |
| 323 | following actions: |
| 324 | |
| 325 | - Decompress more input starting at next_in and update next_in and avail_in |
| 326 | accordingly. If not all input can be processed (because there is not |
| 327 | enough room in the output buffer), next_in is updated and processing |
| 328 | will resume at this point for the next call of inflate(). |
| 329 | |
| 330 | - Provide more output starting at next_out and update next_out and avail_out |
| 331 | accordingly. inflate() provides as much output as possible, until there |
| 332 | is no more input data or no more space in the output buffer (see below |
| 333 | about the flush parameter). |
| 334 | |
| 335 | Before the call of inflate(), the application should ensure that at least |
| 336 | one of the actions is possible, by providing more input and/or consuming |
| 337 | more output, and updating the next_* and avail_* values accordingly. |
| 338 | The application can consume the uncompressed output when it wants, for |
| 339 | example when the output buffer is full (avail_out == 0), or after each |
| 340 | call of inflate(). If inflate returns Z_OK and with zero avail_out, it |
| 341 | must be called again after making room in the output buffer because there |
| 342 | might be more output pending. |
| 343 | |
| 344 | If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much |
| 345 | output as possible to the output buffer. The flushing behavior of inflate is |
| 346 | not specified for values of the flush parameter other than Z_SYNC_FLUSH |
| 347 | and Z_FINISH, but the current implementation actually flushes as much output |
| 348 | as possible anyway. |
| 349 | |
| 350 | inflate() should normally be called until it returns Z_STREAM_END or an |
| 351 | error. However if all decompression is to be performed in a single step |
| 352 | (a single call of inflate), the parameter flush should be set to |
| 353 | Z_FINISH. In this case all pending input is processed and all pending |
| 354 | output is flushed; avail_out must be large enough to hold all the |
| 355 | uncompressed data. (The size of the uncompressed data may have been saved |
| 356 | by the compressor for this purpose.) The next operation on this stream must |
| 357 | be inflateEnd to deallocate the decompression state. The use of Z_FINISH |
| 358 | is never required, but can be used to inform inflate that a faster routine |
| 359 | may be used for the single inflate() call. |
| 360 | |
| 361 | If a preset dictionary is needed at this point (see inflateSetDictionary |
| 362 | below), inflate sets strm-adler to the adler32 checksum of the |
| 363 | dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise |
| 364 | it sets strm->adler to the adler32 checksum of all output produced |
| 365 | so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or |
| 366 | an error code as described below. At the end of the stream, inflate() |
| 367 | checks that its computed adler32 checksum is equal to that saved by the |
| 368 | compressor and returns Z_STREAM_END only if the checksum is correct. |
| 369 | |
| 370 | inflate() returns Z_OK if some progress has been made (more input processed |
| 371 | or more output produced), Z_STREAM_END if the end of the compressed data has |
| 372 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
| 373 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
| 374 | corrupted (input stream not conforming to the zlib format or incorrect |
| 375 | adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent |
| 376 | (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not |
| 377 | enough memory, Z_BUF_ERROR if no progress is possible or if there was not |
| 378 | enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR |
| 379 | case, the application may then call inflateSync to look for a good |
| 380 | compression block. |
| 381 | */ |
| 382 | |
| 383 | |
| 384 | extern int zlib_inflateEnd (z_streamp strm); |
| 385 | /* |
| 386 | All dynamically allocated data structures for this stream are freed. |
| 387 | This function discards any unprocessed input and does not flush any |
| 388 | pending output. |
| 389 | |
| 390 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
| 391 | was inconsistent. In the error case, msg may be set but then points to a |
| 392 | static string (which must not be deallocated). |
| 393 | */ |
| 394 | |
| 395 | /* Advanced functions */ |
| 396 | |
| 397 | /* |
| 398 | The following functions are needed only in some special applications. |
| 399 | */ |
| 400 | |
| 401 | /* |
| 402 | extern int deflateInit2 (z_streamp strm, |
| 403 | int level, |
| 404 | int method, |
| 405 | int windowBits, |
| 406 | int memLevel, |
| 407 | int strategy); |
| 408 | |
| 409 | This is another version of deflateInit with more compression options. The |
| 410 | fields next_in, zalloc, zfree and opaque must be initialized before by |
| 411 | the caller. |
| 412 | |
| 413 | The method parameter is the compression method. It must be Z_DEFLATED in |
| 414 | this version of the library. |
| 415 | |
| 416 | The windowBits parameter is the base two logarithm of the window size |
| 417 | (the size of the history buffer). It should be in the range 8..15 for this |
| 418 | version of the library. Larger values of this parameter result in better |
| 419 | compression at the expense of memory usage. The default value is 15 if |
| 420 | deflateInit is used instead. |
| 421 | |
| 422 | The memLevel parameter specifies how much memory should be allocated |
| 423 | for the internal compression state. memLevel=1 uses minimum memory but |
| 424 | is slow and reduces compression ratio; memLevel=9 uses maximum memory |
| 425 | for optimal speed. The default value is 8. See zconf.h for total memory |
| 426 | usage as a function of windowBits and memLevel. |
| 427 | |
| 428 | The strategy parameter is used to tune the compression algorithm. Use the |
| 429 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
| 430 | filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no |
| 431 | string match). Filtered data consists mostly of small values with a |
| 432 | somewhat random distribution. In this case, the compression algorithm is |
| 433 | tuned to compress them better. The effect of Z_FILTERED is to force more |
| 434 | Huffman coding and less string matching; it is somewhat intermediate |
| 435 | between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects |
| 436 | the compression ratio but not the correctness of the compressed output even |
| 437 | if it is not set appropriately. |
| 438 | |
| 439 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 440 | memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
| 441 | method). msg is set to null if there is no error message. deflateInit2 does |
| 442 | not perform any compression: this will be done by deflate(). |
| 443 | */ |
| 444 | |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 445 | #if 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | extern int zlib_deflateSetDictionary (z_streamp strm, |
| 447 | const Byte *dictionary, |
| 448 | uInt dictLength); |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 449 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 450 | /* |
| 451 | Initializes the compression dictionary from the given byte sequence |
| 452 | without producing any compressed output. This function must be called |
| 453 | immediately after deflateInit, deflateInit2 or deflateReset, before any |
| 454 | call of deflate. The compressor and decompressor must use exactly the same |
| 455 | dictionary (see inflateSetDictionary). |
| 456 | |
| 457 | The dictionary should consist of strings (byte sequences) that are likely |
| 458 | to be encountered later in the data to be compressed, with the most commonly |
| 459 | used strings preferably put towards the end of the dictionary. Using a |
| 460 | dictionary is most useful when the data to be compressed is short and can be |
| 461 | predicted with good accuracy; the data can then be compressed better than |
| 462 | with the default empty dictionary. |
| 463 | |
| 464 | Depending on the size of the compression data structures selected by |
| 465 | deflateInit or deflateInit2, a part of the dictionary may in effect be |
| 466 | discarded, for example if the dictionary is larger than the window size in |
| 467 | deflate or deflate2. Thus the strings most likely to be useful should be |
| 468 | put at the end of the dictionary, not at the front. |
| 469 | |
| 470 | Upon return of this function, strm->adler is set to the Adler32 value |
| 471 | of the dictionary; the decompressor may later use this value to determine |
| 472 | which dictionary has been used by the compressor. (The Adler32 value |
| 473 | applies to the whole dictionary even if only a subset of the dictionary is |
| 474 | actually used by the compressor.) |
| 475 | |
| 476 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
| 477 | parameter is invalid (such as NULL dictionary) or the stream state is |
| 478 | inconsistent (for example if deflate has already been called for this stream |
| 479 | or if the compression method is bsort). deflateSetDictionary does not |
| 480 | perform any compression: this will be done by deflate(). |
| 481 | */ |
| 482 | |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 483 | #if 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | extern int zlib_deflateCopy (z_streamp dest, z_streamp source); |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 485 | #endif |
| 486 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | /* |
| 488 | Sets the destination stream as a complete copy of the source stream. |
| 489 | |
| 490 | This function can be useful when several compression strategies will be |
| 491 | tried, for example when there are several ways of pre-processing the input |
| 492 | data with a filter. The streams that will be discarded should then be freed |
| 493 | by calling deflateEnd. Note that deflateCopy duplicates the internal |
| 494 | compression state which can be quite large, so this strategy is slow and |
| 495 | can consume lots of memory. |
| 496 | |
| 497 | deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
| 498 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
| 499 | (such as zalloc being NULL). msg is left unchanged in both source and |
| 500 | destination. |
| 501 | */ |
| 502 | |
| 503 | extern int zlib_deflateReset (z_streamp strm); |
| 504 | /* |
| 505 | This function is equivalent to deflateEnd followed by deflateInit, |
| 506 | but does not free and reallocate all the internal compression state. |
| 507 | The stream will keep the same compression level and any other attributes |
| 508 | that may have been set by deflateInit2. |
| 509 | |
| 510 | deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 511 | stream state was inconsistent (such as zalloc or state being NULL). |
| 512 | */ |
| 513 | |
Linus Torvalds | 243393c | 2005-08-06 09:39:57 -0700 | [diff] [blame] | 514 | static inline unsigned long deflateBound(unsigned long s) |
| 515 | { |
| 516 | return s + ((s + 7) >> 3) + ((s + 63) >> 6) + 11; |
| 517 | } |
| 518 | |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 519 | #if 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 520 | extern int zlib_deflateParams (z_streamp strm, int level, int strategy); |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 521 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | /* |
| 523 | Dynamically update the compression level and compression strategy. The |
| 524 | interpretation of level and strategy is as in deflateInit2. This can be |
| 525 | used to switch between compression and straight copy of the input data, or |
| 526 | to switch to a different kind of input data requiring a different |
| 527 | strategy. If the compression level is changed, the input available so far |
| 528 | is compressed with the old level (and may be flushed); the new level will |
| 529 | take effect only at the next call of deflate(). |
| 530 | |
| 531 | Before the call of deflateParams, the stream state must be set as for |
| 532 | a call of deflate(), since the currently available input may have to |
| 533 | be compressed and flushed. In particular, strm->avail_out must be non-zero. |
| 534 | |
| 535 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
| 536 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR |
| 537 | if strm->avail_out was zero. |
| 538 | */ |
| 539 | |
| 540 | /* |
| 541 | extern int inflateInit2 (z_streamp strm, int windowBits); |
| 542 | |
| 543 | This is another version of inflateInit with an extra parameter. The |
| 544 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
| 545 | before by the caller. |
| 546 | |
| 547 | The windowBits parameter is the base two logarithm of the maximum window |
| 548 | size (the size of the history buffer). It should be in the range 8..15 for |
| 549 | this version of the library. The default value is 15 if inflateInit is used |
| 550 | instead. If a compressed stream with a larger window size is given as |
| 551 | input, inflate() will return with the error code Z_DATA_ERROR instead of |
| 552 | trying to allocate a larger window. |
| 553 | |
| 554 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 555 | memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative |
| 556 | memLevel). msg is set to null if there is no error message. inflateInit2 |
| 557 | does not perform any decompression apart from reading the zlib header if |
| 558 | present: this will be done by inflate(). (So next_in and avail_in may be |
| 559 | modified, but next_out and avail_out are unchanged.) |
| 560 | */ |
| 561 | |
| 562 | extern int zlib_inflateSetDictionary (z_streamp strm, |
| 563 | const Byte *dictionary, |
| 564 | uInt dictLength); |
| 565 | /* |
| 566 | Initializes the decompression dictionary from the given uncompressed byte |
| 567 | sequence. This function must be called immediately after a call of inflate |
| 568 | if this call returned Z_NEED_DICT. The dictionary chosen by the compressor |
| 569 | can be determined from the Adler32 value returned by this call of |
| 570 | inflate. The compressor and decompressor must use exactly the same |
| 571 | dictionary (see deflateSetDictionary). |
| 572 | |
| 573 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
| 574 | parameter is invalid (such as NULL dictionary) or the stream state is |
| 575 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
| 576 | expected one (incorrect Adler32 value). inflateSetDictionary does not |
| 577 | perform any decompression: this will be done by subsequent calls of |
| 578 | inflate(). |
| 579 | */ |
| 580 | |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 581 | #if 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 582 | extern int zlib_inflateSync (z_streamp strm); |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 583 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 584 | /* |
| 585 | Skips invalid compressed data until a full flush point (see above the |
| 586 | description of deflate with Z_FULL_FLUSH) can be found, or until all |
| 587 | available input is skipped. No output is provided. |
| 588 | |
| 589 | inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
| 590 | if no more input was provided, Z_DATA_ERROR if no flush point has been found, |
| 591 | or Z_STREAM_ERROR if the stream structure was inconsistent. In the success |
| 592 | case, the application may save the current current value of total_in which |
| 593 | indicates where valid compressed data was found. In the error case, the |
| 594 | application may repeatedly call inflateSync, providing more input each time, |
| 595 | until success or end of the input data. |
| 596 | */ |
| 597 | |
| 598 | extern int zlib_inflateReset (z_streamp strm); |
| 599 | /* |
| 600 | This function is equivalent to inflateEnd followed by inflateInit, |
| 601 | but does not free and reallocate all the internal decompression state. |
| 602 | The stream will keep attributes that may have been set by inflateInit2. |
| 603 | |
| 604 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 605 | stream state was inconsistent (such as zalloc or state being NULL). |
| 606 | */ |
| 607 | |
| 608 | extern int zlib_inflateIncomp (z_stream *strm); |
| 609 | /* |
| 610 | This function adds the data at next_in (avail_in bytes) to the output |
| 611 | history without performing any output. There must be no pending output, |
| 612 | and the decompressor must be expecting to see the start of a block. |
| 613 | Calling this function is equivalent to decompressing a stored block |
| 614 | containing the data at next_in (except that the data is not output). |
| 615 | */ |
| 616 | |
| 617 | /* various hacks, don't look :) */ |
| 618 | |
| 619 | /* deflateInit and inflateInit are macros to allow checking the zlib version |
| 620 | * and the compiler's view of z_stream: |
| 621 | */ |
| 622 | extern int zlib_deflateInit_ (z_streamp strm, int level, |
| 623 | const char *version, int stream_size); |
| 624 | extern int zlib_inflateInit_ (z_streamp strm, |
| 625 | const char *version, int stream_size); |
| 626 | extern int zlib_deflateInit2_ (z_streamp strm, int level, int method, |
| 627 | int windowBits, int memLevel, |
| 628 | int strategy, const char *version, |
| 629 | int stream_size); |
| 630 | extern int zlib_inflateInit2_ (z_streamp strm, int windowBits, |
| 631 | const char *version, int stream_size); |
| 632 | #define zlib_deflateInit(strm, level) \ |
| 633 | zlib_deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
| 634 | #define zlib_inflateInit(strm) \ |
| 635 | zlib_inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
| 636 | #define zlib_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
| 637 | zlib_deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
| 638 | (strategy), ZLIB_VERSION, sizeof(z_stream)) |
| 639 | #define zlib_inflateInit2(strm, windowBits) \ |
| 640 | zlib_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
| 641 | |
| 642 | |
| 643 | #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) |
| 644 | struct internal_state {int dummy;}; /* hack for buggy compilers */ |
| 645 | #endif |
| 646 | |
| 647 | extern const char * zlib_zError (int err); |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 648 | #if 0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 649 | extern int zlib_inflateSyncPoint (z_streamp z); |
Adrian Bunk | 87c2ce3 | 2006-01-09 20:54:07 -0800 | [diff] [blame] | 650 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 651 | extern const uLong * zlib_get_crc_table (void); |
| 652 | |
| 653 | #endif /* _ZLIB_H */ |