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| 1 /* zlib.h -- interface of the 'zlib' general purpose compression library |
| 2 version 1.2.5, April 19th, 2010 |
| 3 |
| 4 Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler |
| 5 |
| 6 This software is provided 'as-is', without any express or implied |
| 7 warranty. In no event will the authors be held liable for any damages |
| 8 arising from the use of this software. |
| 9 |
| 10 Permission is granted to anyone to use this software for any purpose, |
| 11 including commercial applications, and to alter it and redistribute it |
| 12 freely, subject to the following restrictions: |
| 13 |
| 14 1. The origin of this software must not be misrepresented; you must not |
| 15 claim that you wrote the original software. If you use this software |
| 16 in a product, an acknowledgment in the product documentation would be |
| 17 appreciated but is not required. |
| 18 2. Altered source versions must be plainly marked as such, and must not be |
| 19 misrepresented as being the original software. |
| 20 3. This notice may not be removed or altered from any source distribution. |
| 21 |
| 22 Jean-loup Gailly Mark Adler |
| 23 jloup@gzip.org madler@alumni.caltech.edu |
| 24 |
| 25 |
| 26 The data format used by the zlib library is described by RFCs (Request for |
| 27 Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt |
| 28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). |
| 29 */ |
| 30 |
| 31 #ifndef ZLIB_H |
| 32 #define ZLIB_H |
| 33 |
| 34 #include "zconf.h" |
| 35 |
| 36 #ifdef __cplusplus |
| 37 extern "C" { |
| 38 #endif |
| 39 |
| 40 #define ZLIB_VERSION "1.2.5" |
| 41 #define ZLIB_VERNUM 0x1250 |
| 42 #define ZLIB_VER_MAJOR 1 |
| 43 #define ZLIB_VER_MINOR 2 |
| 44 #define ZLIB_VER_REVISION 5 |
| 45 #define ZLIB_VER_SUBREVISION 0 |
| 46 |
| 47 /* |
| 48 The 'zlib' compression library provides in-memory compression and |
| 49 decompression functions, including integrity checks of the uncompressed data. |
| 50 This version of the library supports only one compression method (deflation) |
| 51 but other algorithms will be added later and will have the same stream |
| 52 interface. |
| 53 |
| 54 Compression can be done in a single step if the buffers are large enough, |
| 55 or can be done by repeated calls of the compression function. In the latter |
| 56 case, the application must provide more input and/or consume the output |
| 57 (providing more output space) before each call. |
| 58 |
| 59 The compressed data format used by default by the in-memory functions is |
| 60 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped |
| 61 around a deflate stream, which is itself documented in RFC 1951. |
| 62 |
| 63 The library also supports reading and writing files in gzip (.gz) format |
| 64 with an interface similar to that of stdio using the functions that start |
| 65 with "gz". The gzip format is different from the zlib format. gzip is a |
| 66 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. |
| 67 |
| 68 This library can optionally read and write gzip streams in memory as well. |
| 69 |
| 70 The zlib format was designed to be compact and fast for use in memory |
| 71 and on communications channels. The gzip format was designed for single- |
| 72 file compression on file systems, has a larger header than zlib to maintain |
| 73 directory information, and uses a different, slower check method than zlib. |
| 74 |
| 75 The library does not install any signal handler. The decoder checks |
| 76 the consistency of the compressed data, so the library should never crash |
| 77 even in case of corrupted input. |
| 78 */ |
| 79 |
| 80 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
| 81 typedef void (*free_func) OF((voidpf opaque, voidpf address)); |
| 82 |
| 83 struct internal_state; |
| 84 |
| 85 typedef struct z_stream_s { |
| 86 Bytef *next_in; /* next input byte */ |
| 87 uInt avail_in; /* number of bytes available at next_in */ |
| 88 uLong total_in; /* total nb of input bytes read so far */ |
| 89 |
| 90 Bytef *next_out; /* next output byte should be put there */ |
| 91 uInt avail_out; /* remaining free space at next_out */ |
| 92 uLong total_out; /* total nb of bytes output so far */ |
| 93 |
| 94 char *msg; /* last error message, NULL if no error */ |
| 95 struct internal_state FAR *state; /* not visible by applications */ |
| 96 |
| 97 alloc_func zalloc; /* used to allocate the internal state */ |
| 98 free_func zfree; /* used to free the internal state */ |
| 99 voidpf opaque; /* private data object passed to zalloc and zfree */ |
| 100 |
| 101 int data_type; /* best guess about the data type: binary or text */ |
| 102 uLong adler; /* adler32 value of the uncompressed data */ |
| 103 uLong reserved; /* reserved for future use */ |
| 104 int clas; |
| 105 } z_stream; |
| 106 |
| 107 typedef z_stream FAR *z_streamp; |
| 108 |
| 109 /* |
| 110 gzip header information passed to and from zlib routines. See RFC 1952 |
| 111 for more details on the meanings of these fields. |
| 112 */ |
| 113 typedef struct gz_header_s { |
| 114 int text; /* true if compressed data believed to be text */ |
| 115 uLong time; /* modification time */ |
| 116 int xflags; /* extra flags (not used when writing a gzip file) */ |
| 117 int os; /* operating system */ |
| 118 Bytef *extra; /* pointer to extra field or Z_NULL if none */ |
| 119 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ |
| 120 uInt extra_max; /* space at extra (only when reading header) */ |
| 121 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ |
| 122 uInt name_max; /* space at name (only when reading header) */ |
| 123 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ |
| 124 uInt comm_max; /* space at comment (only when reading header) */ |
| 125 int hcrc; /* true if there was or will be a header crc */ |
| 126 int done; /* true when done reading gzip header (not used |
| 127 when writing a gzip file) */ |
| 128 } gz_header; |
| 129 |
| 130 typedef gz_header FAR *gz_headerp; |
| 131 |
| 132 /* |
| 133 The application must update next_in and avail_in when avail_in has dropped |
| 134 to zero. It must update next_out and avail_out when avail_out has dropped |
| 135 to zero. The application must initialize zalloc, zfree and opaque before |
| 136 calling the init function. All other fields are set by the compression |
| 137 library and must not be updated by the application. |
| 138 |
| 139 The opaque value provided by the application will be passed as the first |
| 140 parameter for calls of zalloc and zfree. This can be useful for custom |
| 141 memory management. The compression library attaches no meaning to the |
| 142 opaque value. |
| 143 |
| 144 zalloc must return Z_NULL if there is not enough memory for the object. |
| 145 If zlib is used in a multi-threaded application, zalloc and zfree must be |
| 146 thread safe. |
| 147 |
| 148 On 16-bit systems, the functions zalloc and zfree must be able to allocate |
| 149 exactly 65536 bytes, but will not be required to allocate more than this if |
| 150 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers |
| 151 returned by zalloc for objects of exactly 65536 bytes *must* have their |
| 152 offset normalized to zero. The default allocation function provided by this |
| 153 library ensures this (see zutil.c). To reduce memory requirements and avoid |
| 154 any allocation of 64K objects, at the expense of compression ratio, compile |
| 155 the library with -DMAX_WBITS=14 (see zconf.h). |
| 156 |
| 157 The fields total_in and total_out can be used for statistics or progress |
| 158 reports. After compression, total_in holds the total size of the |
| 159 uncompressed data and may be saved for use in the decompressor (particularly |
| 160 if the decompressor wants to decompress everything in a single step). |
| 161 */ |
| 162 |
| 163 /* constants */ |
| 164 |
| 165 #define Z_NO_FLUSH 0 |
| 166 #define Z_PARTIAL_FLUSH 1 |
| 167 #define Z_SYNC_FLUSH 2 |
| 168 #define Z_FULL_FLUSH 3 |
| 169 #define Z_FINISH 4 |
| 170 #define Z_BLOCK 5 |
| 171 #define Z_TREES 6 |
| 172 /* Allowed flush values; see deflate() and inflate() below for details */ |
| 173 |
| 174 #define Z_OK 0 |
| 175 #define Z_STREAM_END 1 |
| 176 #define Z_NEED_DICT 2 |
| 177 #define Z_ERRNO (-1) |
| 178 #define Z_STREAM_ERROR (-2) |
| 179 #define Z_DATA_ERROR (-3) |
| 180 #define Z_MEM_ERROR (-4) |
| 181 #define Z_BUF_ERROR (-5) |
| 182 #define Z_VERSION_ERROR (-6) |
| 183 /* Return codes for the compression/decompression functions. Negative values |
| 184 * are errors, positive values are used for special but normal events. |
| 185 */ |
| 186 |
| 187 #define Z_NO_COMPRESSION 0 |
| 188 #define Z_BEST_SPEED 1 |
| 189 #define Z_BEST_COMPRESSION 9 |
| 190 #define Z_DEFAULT_COMPRESSION (-1) |
| 191 /* compression levels */ |
| 192 |
| 193 #define Z_FILTERED 1 |
| 194 #define Z_HUFFMAN_ONLY 2 |
| 195 #define Z_RLE 3 |
| 196 #define Z_FIXED 4 |
| 197 #define Z_DEFAULT_STRATEGY 0 |
| 198 /* compression strategy; see deflateInit2() below for details */ |
| 199 |
| 200 #define Z_BINARY 0 |
| 201 #define Z_TEXT 1 |
| 202 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ |
| 203 #define Z_UNKNOWN 2 |
| 204 /* Possible values of the data_type field (though see inflate()) */ |
| 205 |
| 206 #define Z_DEFLATED 8 |
| 207 /* The deflate compression method (the only one supported in this version) */ |
| 208 |
| 209 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
| 210 |
| 211 #define Z_CLASS_STANDARD 0 |
| 212 #define Z_CLASS_COOKIE 1 |
| 213 #define Z_CLASS_HUFFMAN_ONLY 2 |
| 214 |
| 215 #define zlib_version zlibVersion() |
| 216 /* for compatibility with versions < 1.0.2 */ |
| 217 |
| 218 |
| 219 /* basic functions */ |
| 220 |
| 221 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
| 222 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
| 223 If the first character differs, the library code actually used is not |
| 224 compatible with the zlib.h header file used by the application. This check |
| 225 is automatically made by deflateInit and inflateInit. |
| 226 */ |
| 227 |
| 228 /* |
| 229 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); |
| 230 |
| 231 Initializes the internal stream state for compression. The fields |
| 232 zalloc, zfree and opaque must be initialized before by the caller. If |
| 233 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default |
| 234 allocation functions. |
| 235 |
| 236 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
| 237 1 gives best speed, 9 gives best compression, 0 gives no compression at all |
| 238 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION |
| 239 requests a default compromise between speed and compression (currently |
| 240 equivalent to level 6). |
| 241 |
| 242 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 243 memory, Z_STREAM_ERROR if level is not a valid compression level, or |
| 244 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
| 245 with the version assumed by the caller (ZLIB_VERSION). msg is set to null |
| 246 if there is no error message. deflateInit does not perform any compression: |
| 247 this will be done by deflate(). |
| 248 */ |
| 249 |
| 250 |
| 251 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
| 252 /* |
| 253 deflate compresses as much data as possible, and stops when the input |
| 254 buffer becomes empty or the output buffer becomes full. It may introduce |
| 255 some output latency (reading input without producing any output) except when |
| 256 forced to flush. |
| 257 |
| 258 The detailed semantics are as follows. deflate performs one or both of the |
| 259 following actions: |
| 260 |
| 261 - Compress more input starting at next_in and update next_in and avail_in |
| 262 accordingly. If not all input can be processed (because there is not |
| 263 enough room in the output buffer), next_in and avail_in are updated and |
| 264 processing will resume at this point for the next call of deflate(). |
| 265 |
| 266 - Provide more output starting at next_out and update next_out and avail_out |
| 267 accordingly. This action is forced if the parameter flush is non zero. |
| 268 Forcing flush frequently degrades the compression ratio, so this parameter |
| 269 should be set only when necessary (in interactive applications). Some |
| 270 output may be provided even if flush is not set. |
| 271 |
| 272 Before the call of deflate(), the application should ensure that at least |
| 273 one of the actions is possible, by providing more input and/or consuming more |
| 274 output, and updating avail_in or avail_out accordingly; avail_out should |
| 275 never be zero before the call. The application can consume the compressed |
| 276 output when it wants, for example when the output buffer is full (avail_out |
| 277 == 0), or after each call of deflate(). If deflate returns Z_OK and with |
| 278 zero avail_out, it must be called again after making room in the output |
| 279 buffer because there might be more output pending. |
| 280 |
| 281 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to |
| 282 decide how much data to accumulate before producing output, in order to |
| 283 maximize compression. |
| 284 |
| 285 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
| 286 flushed to the output buffer and the output is aligned on a byte boundary, so |
| 287 that the decompressor can get all input data available so far. (In |
| 288 particular avail_in is zero after the call if enough output space has been |
| 289 provided before the call.) Flushing may degrade compression for some |
| 290 compression algorithms and so it should be used only when necessary. This |
| 291 completes the current deflate block and follows it with an empty stored block |
| 292 that is three bits plus filler bits to the next byte, followed by four bytes |
| 293 (00 00 ff ff). |
| 294 |
| 295 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the |
| 296 output buffer, but the output is not aligned to a byte boundary. All of the |
| 297 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. |
| 298 This completes the current deflate block and follows it with an empty fixed |
| 299 codes block that is 10 bits long. This assures that enough bytes are output |
| 300 in order for the decompressor to finish the block before the empty fixed code |
| 301 block. |
| 302 |
| 303 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as |
| 304 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to |
| 305 seven bits of the current block are held to be written as the next byte after |
| 306 the next deflate block is completed. In this case, the decompressor may not |
| 307 be provided enough bits at this point in order to complete decompression of |
| 308 the data provided so far to the compressor. It may need to wait for the next |
| 309 block to be emitted. This is for advanced applications that need to control |
| 310 the emission of deflate blocks. |
| 311 |
| 312 If flush is set to Z_FULL_FLUSH, all output is flushed as with |
| 313 Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
| 314 restart from this point if previous compressed data has been damaged or if |
| 315 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
| 316 compression. |
| 317 |
| 318 If deflate returns with avail_out == 0, this function must be called again |
| 319 with the same value of the flush parameter and more output space (updated |
| 320 avail_out), until the flush is complete (deflate returns with non-zero |
| 321 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
| 322 avail_out is greater than six to avoid repeated flush markers due to |
| 323 avail_out == 0 on return. |
| 324 |
| 325 If the parameter flush is set to Z_FINISH, pending input is processed, |
| 326 pending output is flushed and deflate returns with Z_STREAM_END if there was |
| 327 enough output space; if deflate returns with Z_OK, this function must be |
| 328 called again with Z_FINISH and more output space (updated avail_out) but no |
| 329 more input data, until it returns with Z_STREAM_END or an error. After |
| 330 deflate has returned Z_STREAM_END, the only possible operations on the stream |
| 331 are deflateReset or deflateEnd. |
| 332 |
| 333 Z_FINISH can be used immediately after deflateInit if all the compression |
| 334 is to be done in a single step. In this case, avail_out must be at least the |
| 335 value returned by deflateBound (see below). If deflate does not return |
| 336 Z_STREAM_END, then it must be called again as described above. |
| 337 |
| 338 deflate() sets strm->adler to the adler32 checksum of all input read |
| 339 so far (that is, total_in bytes). |
| 340 |
| 341 deflate() may update strm->data_type if it can make a good guess about |
| 342 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered |
| 343 binary. This field is only for information purposes and does not affect the |
| 344 compression algorithm in any manner. |
| 345 |
| 346 deflate() returns Z_OK if some progress has been made (more input |
| 347 processed or more output produced), Z_STREAM_END if all input has been |
| 348 consumed and all output has been produced (only when flush is set to |
| 349 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
| 350 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible |
| 351 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not |
| 352 fatal, and deflate() can be called again with more input and more output |
| 353 space to continue compressing. |
| 354 */ |
| 355 |
| 356 |
| 357 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); |
| 358 /* |
| 359 All dynamically allocated data structures for this stream are freed. |
| 360 This function discards any unprocessed input and does not flush any pending |
| 361 output. |
| 362 |
| 363 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
| 364 stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
| 365 prematurely (some input or output was discarded). In the error case, msg |
| 366 may be set but then points to a static string (which must not be |
| 367 deallocated). |
| 368 */ |
| 369 |
| 370 |
| 371 /* |
| 372 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
| 373 |
| 374 Initializes the internal stream state for decompression. The fields |
| 375 next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
| 376 the caller. If next_in is not Z_NULL and avail_in is large enough (the |
| 377 exact value depends on the compression method), inflateInit determines the |
| 378 compression method from the zlib header and allocates all data structures |
| 379 accordingly; otherwise the allocation will be deferred to the first call of |
| 380 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to |
| 381 use default allocation functions. |
| 382 |
| 383 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 384 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
| 385 version assumed by the caller, or Z_STREAM_ERROR if the parameters are |
| 386 invalid, such as a null pointer to the structure. msg is set to null if |
| 387 there is no error message. inflateInit does not perform any decompression |
| 388 apart from possibly reading the zlib header if present: actual decompression |
| 389 will be done by inflate(). (So next_in and avail_in may be modified, but |
| 390 next_out and avail_out are unused and unchanged.) The current implementation |
| 391 of inflateInit() does not process any header information -- that is deferred |
| 392 until inflate() is called. |
| 393 */ |
| 394 |
| 395 |
| 396 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); |
| 397 /* |
| 398 inflate decompresses as much data as possible, and stops when the input |
| 399 buffer becomes empty or the output buffer becomes full. It may introduce |
| 400 some output latency (reading input without producing any output) except when |
| 401 forced to flush. |
| 402 |
| 403 The detailed semantics are as follows. inflate performs one or both of the |
| 404 following actions: |
| 405 |
| 406 - Decompress more input starting at next_in and update next_in and avail_in |
| 407 accordingly. If not all input can be processed (because there is not |
| 408 enough room in the output buffer), next_in is updated and processing will |
| 409 resume at this point for the next call of inflate(). |
| 410 |
| 411 - Provide more output starting at next_out and update next_out and avail_out |
| 412 accordingly. inflate() provides as much output as possible, until there is |
| 413 no more input data or no more space in the output buffer (see below about |
| 414 the flush parameter). |
| 415 |
| 416 Before the call of inflate(), the application should ensure that at least |
| 417 one of the actions is possible, by providing more input and/or consuming more |
| 418 output, and updating the next_* and avail_* values accordingly. The |
| 419 application can consume the uncompressed output when it wants, for example |
| 420 when the output buffer is full (avail_out == 0), or after each call of |
| 421 inflate(). If inflate returns Z_OK and with zero avail_out, it must be |
| 422 called again after making room in the output buffer because there might be |
| 423 more output pending. |
| 424 |
| 425 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, |
| 426 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much |
| 427 output as possible to the output buffer. Z_BLOCK requests that inflate() |
| 428 stop if and when it gets to the next deflate block boundary. When decoding |
| 429 the zlib or gzip format, this will cause inflate() to return immediately |
| 430 after the header and before the first block. When doing a raw inflate, |
| 431 inflate() will go ahead and process the first block, and will return when it |
| 432 gets to the end of that block, or when it runs out of data. |
| 433 |
| 434 The Z_BLOCK option assists in appending to or combining deflate streams. |
| 435 Also to assist in this, on return inflate() will set strm->data_type to the |
| 436 number of unused bits in the last byte taken from strm->next_in, plus 64 if |
| 437 inflate() is currently decoding the last block in the deflate stream, plus |
| 438 128 if inflate() returned immediately after decoding an end-of-block code or |
| 439 decoding the complete header up to just before the first byte of the deflate |
| 440 stream. The end-of-block will not be indicated until all of the uncompressed |
| 441 data from that block has been written to strm->next_out. The number of |
| 442 unused bits may in general be greater than seven, except when bit 7 of |
| 443 data_type is set, in which case the number of unused bits will be less than |
| 444 eight. data_type is set as noted here every time inflate() returns for all |
| 445 flush options, and so can be used to determine the amount of currently |
| 446 consumed input in bits. |
| 447 |
| 448 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the |
| 449 end of each deflate block header is reached, before any actual data in that |
| 450 block is decoded. This allows the caller to determine the length of the |
| 451 deflate block header for later use in random access within a deflate block. |
| 452 256 is added to the value of strm->data_type when inflate() returns |
| 453 immediately after reaching the end of the deflate block header. |
| 454 |
| 455 inflate() should normally be called until it returns Z_STREAM_END or an |
| 456 error. However if all decompression is to be performed in a single step (a |
| 457 single call of inflate), the parameter flush should be set to Z_FINISH. In |
| 458 this case all pending input is processed and all pending output is flushed; |
| 459 avail_out must be large enough to hold all the uncompressed data. (The size |
| 460 of the uncompressed data may have been saved by the compressor for this |
| 461 purpose.) The next operation on this stream must be inflateEnd to deallocate |
| 462 the decompression state. The use of Z_FINISH is never required, but can be |
| 463 used to inform inflate that a faster approach may be used for the single |
| 464 inflate() call. |
| 465 |
| 466 In this implementation, inflate() always flushes as much output as |
| 467 possible to the output buffer, and always uses the faster approach on the |
| 468 first call. So the only effect of the flush parameter in this implementation |
| 469 is on the return value of inflate(), as noted below, or when it returns early |
| 470 because Z_BLOCK or Z_TREES is used. |
| 471 |
| 472 If a preset dictionary is needed after this call (see inflateSetDictionary |
| 473 below), inflate sets strm->adler to the adler32 checksum of the dictionary |
| 474 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
| 475 strm->adler to the adler32 checksum of all output produced so far (that is, |
| 476 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described |
| 477 below. At the end of the stream, inflate() checks that its computed adler32 |
| 478 checksum is equal to that saved by the compressor and returns Z_STREAM_END |
| 479 only if the checksum is correct. |
| 480 |
| 481 inflate() can decompress and check either zlib-wrapped or gzip-wrapped |
| 482 deflate data. The header type is detected automatically, if requested when |
| 483 initializing with inflateInit2(). Any information contained in the gzip |
| 484 header is not retained, so applications that need that information should |
| 485 instead use raw inflate, see inflateInit2() below, or inflateBack() and |
| 486 perform their own processing of the gzip header and trailer. |
| 487 |
| 488 inflate() returns Z_OK if some progress has been made (more input processed |
| 489 or more output produced), Z_STREAM_END if the end of the compressed data has |
| 490 been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
| 491 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
| 492 corrupted (input stream not conforming to the zlib format or incorrect check |
| 493 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example |
| 494 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, |
| 495 Z_BUF_ERROR if no progress is possible or if there was not enough room in the |
| 496 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
| 497 inflate() can be called again with more input and more output space to |
| 498 continue decompressing. If Z_DATA_ERROR is returned, the application may |
| 499 then call inflateSync() to look for a good compression block if a partial |
| 500 recovery of the data is desired. |
| 501 */ |
| 502 |
| 503 |
| 504 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); |
| 505 /* |
| 506 All dynamically allocated data structures for this stream are freed. |
| 507 This function discards any unprocessed input and does not flush any pending |
| 508 output. |
| 509 |
| 510 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
| 511 was inconsistent. In the error case, msg may be set but then points to a |
| 512 static string (which must not be deallocated). |
| 513 */ |
| 514 |
| 515 |
| 516 /* Advanced functions */ |
| 517 |
| 518 /* |
| 519 The following functions are needed only in some special applications. |
| 520 */ |
| 521 |
| 522 /* |
| 523 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, |
| 524 int level, |
| 525 int method, |
| 526 int windowBits, |
| 527 int memLevel, |
| 528 int strategy)); |
| 529 |
| 530 This is another version of deflateInit with more compression options. The |
| 531 fields next_in, zalloc, zfree and opaque must be initialized before by the |
| 532 caller. |
| 533 |
| 534 The method parameter is the compression method. It must be Z_DEFLATED in |
| 535 this version of the library. |
| 536 |
| 537 The windowBits parameter is the base two logarithm of the window size |
| 538 (the size of the history buffer). It should be in the range 8..15 for this |
| 539 version of the library. Larger values of this parameter result in better |
| 540 compression at the expense of memory usage. The default value is 15 if |
| 541 deflateInit is used instead. |
| 542 |
| 543 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
| 544 determines the window size. deflate() will then generate raw deflate data |
| 545 with no zlib header or trailer, and will not compute an adler32 check value. |
| 546 |
| 547 windowBits can also be greater than 15 for optional gzip encoding. Add |
| 548 16 to windowBits to write a simple gzip header and trailer around the |
| 549 compressed data instead of a zlib wrapper. The gzip header will have no |
| 550 file name, no extra data, no comment, no modification time (set to zero), no |
| 551 header crc, and the operating system will be set to 255 (unknown). If a |
| 552 gzip stream is being written, strm->adler is a crc32 instead of an adler32. |
| 553 |
| 554 The memLevel parameter specifies how much memory should be allocated |
| 555 for the internal compression state. memLevel=1 uses minimum memory but is |
| 556 slow and reduces compression ratio; memLevel=9 uses maximum memory for |
| 557 optimal speed. The default value is 8. See zconf.h for total memory usage |
| 558 as a function of windowBits and memLevel. |
| 559 |
| 560 The strategy parameter is used to tune the compression algorithm. Use the |
| 561 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
| 562 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no |
| 563 string match), or Z_RLE to limit match distances to one (run-length |
| 564 encoding). Filtered data consists mostly of small values with a somewhat |
| 565 random distribution. In this case, the compression algorithm is tuned to |
| 566 compress them better. The effect of Z_FILTERED is to force more Huffman |
| 567 coding and less string matching; it is somewhat intermediate between |
| 568 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as |
| 569 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The |
| 570 strategy parameter only affects the compression ratio but not the |
| 571 correctness of the compressed output even if it is not set appropriately. |
| 572 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler |
| 573 decoder for special applications. |
| 574 |
| 575 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 576 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid |
| 577 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is |
| 578 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is |
| 579 set to null if there is no error message. deflateInit2 does not perform any |
| 580 compression: this will be done by deflate(). |
| 581 */ |
| 582 |
| 583 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
| 584 const Bytef *dictionary, |
| 585 uInt dictLength)); |
| 586 /* |
| 587 Initializes the compression dictionary from the given byte sequence |
| 588 without producing any compressed output. This function must be called |
| 589 immediately after deflateInit, deflateInit2 or deflateReset, before any call |
| 590 of deflate. The compressor and decompressor must use exactly the same |
| 591 dictionary (see inflateSetDictionary). |
| 592 |
| 593 The dictionary should consist of strings (byte sequences) that are likely |
| 594 to be encountered later in the data to be compressed, with the most commonly |
| 595 used strings preferably put towards the end of the dictionary. Using a |
| 596 dictionary is most useful when the data to be compressed is short and can be |
| 597 predicted with good accuracy; the data can then be compressed better than |
| 598 with the default empty dictionary. |
| 599 |
| 600 Depending on the size of the compression data structures selected by |
| 601 deflateInit or deflateInit2, a part of the dictionary may in effect be |
| 602 discarded, for example if the dictionary is larger than the window size |
| 603 provided in deflateInit or deflateInit2. Thus the strings most likely to be |
| 604 useful should be put at the end of the dictionary, not at the front. In |
| 605 addition, the current implementation of deflate will use at most the window |
| 606 size minus 262 bytes of the provided dictionary. |
| 607 |
| 608 Upon return of this function, strm->adler is set to the adler32 value |
| 609 of the dictionary; the decompressor may later use this value to determine |
| 610 which dictionary has been used by the compressor. (The adler32 value |
| 611 applies to the whole dictionary even if only a subset of the dictionary is |
| 612 actually used by the compressor.) If a raw deflate was requested, then the |
| 613 adler32 value is not computed and strm->adler is not set. |
| 614 |
| 615 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
| 616 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
| 617 inconsistent (for example if deflate has already been called for this stream |
| 618 or if the compression method is bsort). deflateSetDictionary does not |
| 619 perform any compression: this will be done by deflate(). |
| 620 */ |
| 621 |
| 622 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, |
| 623 z_streamp source)); |
| 624 /* |
| 625 Sets the destination stream as a complete copy of the source stream. |
| 626 |
| 627 This function can be useful when several compression strategies will be |
| 628 tried, for example when there are several ways of pre-processing the input |
| 629 data with a filter. The streams that will be discarded should then be freed |
| 630 by calling deflateEnd. Note that deflateCopy duplicates the internal |
| 631 compression state which can be quite large, so this strategy is slow and can |
| 632 consume lots of memory. |
| 633 |
| 634 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
| 635 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
| 636 (such as zalloc being Z_NULL). msg is left unchanged in both source and |
| 637 destination. |
| 638 */ |
| 639 |
| 640 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); |
| 641 /* |
| 642 This function is equivalent to deflateEnd followed by deflateInit, |
| 643 but does not free and reallocate all the internal compression state. The |
| 644 stream will keep the same compression level and any other attributes that |
| 645 may have been set by deflateInit2. |
| 646 |
| 647 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 648 stream state was inconsistent (such as zalloc or state being Z_NULL). |
| 649 */ |
| 650 |
| 651 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, |
| 652 int level, |
| 653 int strategy)); |
| 654 /* |
| 655 Dynamically update the compression level and compression strategy. The |
| 656 interpretation of level and strategy is as in deflateInit2. This can be |
| 657 used to switch between compression and straight copy of the input data, or |
| 658 to switch to a different kind of input data requiring a different strategy. |
| 659 If the compression level is changed, the input available so far is |
| 660 compressed with the old level (and may be flushed); the new level will take |
| 661 effect only at the next call of deflate(). |
| 662 |
| 663 Before the call of deflateParams, the stream state must be set as for |
| 664 a call of deflate(), since the currently available input may have to be |
| 665 compressed and flushed. In particular, strm->avail_out must be non-zero. |
| 666 |
| 667 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
| 668 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if |
| 669 strm->avail_out was zero. |
| 670 */ |
| 671 |
| 672 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, |
| 673 int good_length, |
| 674 int max_lazy, |
| 675 int nice_length, |
| 676 int max_chain)); |
| 677 /* |
| 678 Fine tune deflate's internal compression parameters. This should only be |
| 679 used by someone who understands the algorithm used by zlib's deflate for |
| 680 searching for the best matching string, and even then only by the most |
| 681 fanatic optimizer trying to squeeze out the last compressed bit for their |
| 682 specific input data. Read the deflate.c source code for the meaning of the |
| 683 max_lazy, good_length, nice_length, and max_chain parameters. |
| 684 |
| 685 deflateTune() can be called after deflateInit() or deflateInit2(), and |
| 686 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. |
| 687 */ |
| 688 |
| 689 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, |
| 690 uLong sourceLen)); |
| 691 /* |
| 692 deflateBound() returns an upper bound on the compressed size after |
| 693 deflation of sourceLen bytes. It must be called after deflateInit() or |
| 694 deflateInit2(), and after deflateSetHeader(), if used. This would be used |
| 695 to allocate an output buffer for deflation in a single pass, and so would be |
| 696 called before deflate(). |
| 697 */ |
| 698 |
| 699 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, |
| 700 int bits, |
| 701 int value)); |
| 702 /* |
| 703 deflatePrime() inserts bits in the deflate output stream. The intent |
| 704 is that this function is used to start off the deflate output with the bits |
| 705 leftover from a previous deflate stream when appending to it. As such, this |
| 706 function can only be used for raw deflate, and must be used before the first |
| 707 deflate() call after a deflateInit2() or deflateReset(). bits must be less |
| 708 than or equal to 16, and that many of the least significant bits of value |
| 709 will be inserted in the output. |
| 710 |
| 711 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 712 stream state was inconsistent. |
| 713 */ |
| 714 |
| 715 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, |
| 716 gz_headerp head)); |
| 717 /* |
| 718 deflateSetHeader() provides gzip header information for when a gzip |
| 719 stream is requested by deflateInit2(). deflateSetHeader() may be called |
| 720 after deflateInit2() or deflateReset() and before the first call of |
| 721 deflate(). The text, time, os, extra field, name, and comment information |
| 722 in the provided gz_header structure are written to the gzip header (xflag is |
| 723 ignored -- the extra flags are set according to the compression level). The |
| 724 caller must assure that, if not Z_NULL, name and comment are terminated with |
| 725 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are |
| 726 available there. If hcrc is true, a gzip header crc is included. Note that |
| 727 the current versions of the command-line version of gzip (up through version |
| 728 1.3.x) do not support header crc's, and will report that it is a "multi-part |
| 729 gzip file" and give up. |
| 730 |
| 731 If deflateSetHeader is not used, the default gzip header has text false, |
| 732 the time set to zero, and os set to 255, with no extra, name, or comment |
| 733 fields. The gzip header is returned to the default state by deflateReset(). |
| 734 |
| 735 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 736 stream state was inconsistent. |
| 737 */ |
| 738 |
| 739 /* |
| 740 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
| 741 int windowBits)); |
| 742 |
| 743 This is another version of inflateInit with an extra parameter. The |
| 744 fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
| 745 before by the caller. |
| 746 |
| 747 The windowBits parameter is the base two logarithm of the maximum window |
| 748 size (the size of the history buffer). It should be in the range 8..15 for |
| 749 this version of the library. The default value is 15 if inflateInit is used |
| 750 instead. windowBits must be greater than or equal to the windowBits value |
| 751 provided to deflateInit2() while compressing, or it must be equal to 15 if |
| 752 deflateInit2() was not used. If a compressed stream with a larger window |
| 753 size is given as input, inflate() will return with the error code |
| 754 Z_DATA_ERROR instead of trying to allocate a larger window. |
| 755 |
| 756 windowBits can also be zero to request that inflate use the window size in |
| 757 the zlib header of the compressed stream. |
| 758 |
| 759 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
| 760 determines the window size. inflate() will then process raw deflate data, |
| 761 not looking for a zlib or gzip header, not generating a check value, and not |
| 762 looking for any check values for comparison at the end of the stream. This |
| 763 is for use with other formats that use the deflate compressed data format |
| 764 such as zip. Those formats provide their own check values. If a custom |
| 765 format is developed using the raw deflate format for compressed data, it is |
| 766 recommended that a check value such as an adler32 or a crc32 be applied to |
| 767 the uncompressed data as is done in the zlib, gzip, and zip formats. For |
| 768 most applications, the zlib format should be used as is. Note that comments |
| 769 above on the use in deflateInit2() applies to the magnitude of windowBits. |
| 770 |
| 771 windowBits can also be greater than 15 for optional gzip decoding. Add |
| 772 32 to windowBits to enable zlib and gzip decoding with automatic header |
| 773 detection, or add 16 to decode only the gzip format (the zlib format will |
| 774 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a |
| 775 crc32 instead of an adler32. |
| 776 |
| 777 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 778 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
| 779 version assumed by the caller, or Z_STREAM_ERROR if the parameters are |
| 780 invalid, such as a null pointer to the structure. msg is set to null if |
| 781 there is no error message. inflateInit2 does not perform any decompression |
| 782 apart from possibly reading the zlib header if present: actual decompression |
| 783 will be done by inflate(). (So next_in and avail_in may be modified, but |
| 784 next_out and avail_out are unused and unchanged.) The current implementation |
| 785 of inflateInit2() does not process any header information -- that is |
| 786 deferred until inflate() is called. |
| 787 */ |
| 788 |
| 789 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, |
| 790 const Bytef *dictionary, |
| 791 uInt dictLength)); |
| 792 /* |
| 793 Initializes the decompression dictionary from the given uncompressed byte |
| 794 sequence. This function must be called immediately after a call of inflate, |
| 795 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor |
| 796 can be determined from the adler32 value returned by that call of inflate. |
| 797 The compressor and decompressor must use exactly the same dictionary (see |
| 798 deflateSetDictionary). For raw inflate, this function can be called |
| 799 immediately after inflateInit2() or inflateReset() and before any call of |
| 800 inflate() to set the dictionary. The application must insure that the |
| 801 dictionary that was used for compression is provided. |
| 802 |
| 803 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
| 804 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
| 805 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
| 806 expected one (incorrect adler32 value). inflateSetDictionary does not |
| 807 perform any decompression: this will be done by subsequent calls of |
| 808 inflate(). |
| 809 */ |
| 810 |
| 811 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); |
| 812 /* |
| 813 Skips invalid compressed data until a full flush point (see above the |
| 814 description of deflate with Z_FULL_FLUSH) can be found, or until all |
| 815 available input is skipped. No output is provided. |
| 816 |
| 817 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
| 818 if no more input was provided, Z_DATA_ERROR if no flush point has been |
| 819 found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the |
| 820 success case, the application may save the current current value of total_in |
| 821 which indicates where valid compressed data was found. In the error case, |
| 822 the application may repeatedly call inflateSync, providing more input each |
| 823 time, until success or end of the input data. |
| 824 */ |
| 825 |
| 826 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, |
| 827 z_streamp source)); |
| 828 /* |
| 829 Sets the destination stream as a complete copy of the source stream. |
| 830 |
| 831 This function can be useful when randomly accessing a large stream. The |
| 832 first pass through the stream can periodically record the inflate state, |
| 833 allowing restarting inflate at those points when randomly accessing the |
| 834 stream. |
| 835 |
| 836 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
| 837 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
| 838 (such as zalloc being Z_NULL). msg is left unchanged in both source and |
| 839 destination. |
| 840 */ |
| 841 |
| 842 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); |
| 843 /* |
| 844 This function is equivalent to inflateEnd followed by inflateInit, |
| 845 but does not free and reallocate all the internal decompression state. The |
| 846 stream will keep attributes that may have been set by inflateInit2. |
| 847 |
| 848 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 849 stream state was inconsistent (such as zalloc or state being Z_NULL). |
| 850 */ |
| 851 |
| 852 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, |
| 853 int windowBits)); |
| 854 /* |
| 855 This function is the same as inflateReset, but it also permits changing |
| 856 the wrap and window size requests. The windowBits parameter is interpreted |
| 857 the same as it is for inflateInit2. |
| 858 |
| 859 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 860 stream state was inconsistent (such as zalloc or state being Z_NULL), or if |
| 861 the windowBits parameter is invalid. |
| 862 */ |
| 863 |
| 864 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, |
| 865 int bits, |
| 866 int value)); |
| 867 /* |
| 868 This function inserts bits in the inflate input stream. The intent is |
| 869 that this function is used to start inflating at a bit position in the |
| 870 middle of a byte. The provided bits will be used before any bytes are used |
| 871 from next_in. This function should only be used with raw inflate, and |
| 872 should be used before the first inflate() call after inflateInit2() or |
| 873 inflateReset(). bits must be less than or equal to 16, and that many of the |
| 874 least significant bits of value will be inserted in the input. |
| 875 |
| 876 If bits is negative, then the input stream bit buffer is emptied. Then |
| 877 inflatePrime() can be called again to put bits in the buffer. This is used |
| 878 to clear out bits leftover after feeding inflate a block description prior |
| 879 to feeding inflate codes. |
| 880 |
| 881 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 882 stream state was inconsistent. |
| 883 */ |
| 884 |
| 885 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); |
| 886 /* |
| 887 This function returns two values, one in the lower 16 bits of the return |
| 888 value, and the other in the remaining upper bits, obtained by shifting the |
| 889 return value down 16 bits. If the upper value is -1 and the lower value is |
| 890 zero, then inflate() is currently decoding information outside of a block. |
| 891 If the upper value is -1 and the lower value is non-zero, then inflate is in |
| 892 the middle of a stored block, with the lower value equaling the number of |
| 893 bytes from the input remaining to copy. If the upper value is not -1, then |
| 894 it is the number of bits back from the current bit position in the input of |
| 895 the code (literal or length/distance pair) currently being processed. In |
| 896 that case the lower value is the number of bytes already emitted for that |
| 897 code. |
| 898 |
| 899 A code is being processed if inflate is waiting for more input to complete |
| 900 decoding of the code, or if it has completed decoding but is waiting for |
| 901 more output space to write the literal or match data. |
| 902 |
| 903 inflateMark() is used to mark locations in the input data for random |
| 904 access, which may be at bit positions, and to note those cases where the |
| 905 output of a code may span boundaries of random access blocks. The current |
| 906 location in the input stream can be determined from avail_in and data_type |
| 907 as noted in the description for the Z_BLOCK flush parameter for inflate. |
| 908 |
| 909 inflateMark returns the value noted above or -1 << 16 if the provided |
| 910 source stream state was inconsistent. |
| 911 */ |
| 912 |
| 913 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, |
| 914 gz_headerp head)); |
| 915 /* |
| 916 inflateGetHeader() requests that gzip header information be stored in the |
| 917 provided gz_header structure. inflateGetHeader() may be called after |
| 918 inflateInit2() or inflateReset(), and before the first call of inflate(). |
| 919 As inflate() processes the gzip stream, head->done is zero until the header |
| 920 is completed, at which time head->done is set to one. If a zlib stream is |
| 921 being decoded, then head->done is set to -1 to indicate that there will be |
| 922 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be |
| 923 used to force inflate() to return immediately after header processing is |
| 924 complete and before any actual data is decompressed. |
| 925 |
| 926 The text, time, xflags, and os fields are filled in with the gzip header |
| 927 contents. hcrc is set to true if there is a header CRC. (The header CRC |
| 928 was valid if done is set to one.) If extra is not Z_NULL, then extra_max |
| 929 contains the maximum number of bytes to write to extra. Once done is true, |
| 930 extra_len contains the actual extra field length, and extra contains the |
| 931 extra field, or that field truncated if extra_max is less than extra_len. |
| 932 If name is not Z_NULL, then up to name_max characters are written there, |
| 933 terminated with a zero unless the length is greater than name_max. If |
| 934 comment is not Z_NULL, then up to comm_max characters are written there, |
| 935 terminated with a zero unless the length is greater than comm_max. When any |
| 936 of extra, name, or comment are not Z_NULL and the respective field is not |
| 937 present in the header, then that field is set to Z_NULL to signal its |
| 938 absence. This allows the use of deflateSetHeader() with the returned |
| 939 structure to duplicate the header. However if those fields are set to |
| 940 allocated memory, then the application will need to save those pointers |
| 941 elsewhere so that they can be eventually freed. |
| 942 |
| 943 If inflateGetHeader is not used, then the header information is simply |
| 944 discarded. The header is always checked for validity, including the header |
| 945 CRC if present. inflateReset() will reset the process to discard the header |
| 946 information. The application would need to call inflateGetHeader() again to |
| 947 retrieve the header from the next gzip stream. |
| 948 |
| 949 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 950 stream state was inconsistent. |
| 951 */ |
| 952 |
| 953 /* |
| 954 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, |
| 955 unsigned char FAR *window)); |
| 956 |
| 957 Initialize the internal stream state for decompression using inflateBack() |
| 958 calls. The fields zalloc, zfree and opaque in strm must be initialized |
| 959 before the call. If zalloc and zfree are Z_NULL, then the default library- |
| 960 derived memory allocation routines are used. windowBits is the base two |
| 961 logarithm of the window size, in the range 8..15. window is a caller |
| 962 supplied buffer of that size. Except for special applications where it is |
| 963 assured that deflate was used with small window sizes, windowBits must be 15 |
| 964 and a 32K byte window must be supplied to be able to decompress general |
| 965 deflate streams. |
| 966 |
| 967 See inflateBack() for the usage of these routines. |
| 968 |
| 969 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of |
| 970 the paramaters are invalid, Z_MEM_ERROR if the internal state could not be |
| 971 allocated, or Z_VERSION_ERROR if the version of the library does not match |
| 972 the version of the header file. |
| 973 */ |
| 974 |
| 975 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); |
| 976 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); |
| 977 |
| 978 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, |
| 979 in_func in, void FAR *in_desc, |
| 980 out_func out, void FAR *out_desc)); |
| 981 /* |
| 982 inflateBack() does a raw inflate with a single call using a call-back |
| 983 interface for input and output. This is more efficient than inflate() for |
| 984 file i/o applications in that it avoids copying between the output and the |
| 985 sliding window by simply making the window itself the output buffer. This |
| 986 function trusts the application to not change the output buffer passed by |
| 987 the output function, at least until inflateBack() returns. |
| 988 |
| 989 inflateBackInit() must be called first to allocate the internal state |
| 990 and to initialize the state with the user-provided window buffer. |
| 991 inflateBack() may then be used multiple times to inflate a complete, raw |
| 992 deflate stream with each call. inflateBackEnd() is then called to free the |
| 993 allocated state. |
| 994 |
| 995 A raw deflate stream is one with no zlib or gzip header or trailer. |
| 996 This routine would normally be used in a utility that reads zip or gzip |
| 997 files and writes out uncompressed files. The utility would decode the |
| 998 header and process the trailer on its own, hence this routine expects only |
| 999 the raw deflate stream to decompress. This is different from the normal |
| 1000 behavior of inflate(), which expects either a zlib or gzip header and |
| 1001 trailer around the deflate stream. |
| 1002 |
| 1003 inflateBack() uses two subroutines supplied by the caller that are then |
| 1004 called by inflateBack() for input and output. inflateBack() calls those |
| 1005 routines until it reads a complete deflate stream and writes out all of the |
| 1006 uncompressed data, or until it encounters an error. The function's |
| 1007 parameters and return types are defined above in the in_func and out_func |
| 1008 typedefs. inflateBack() will call in(in_desc, &buf) which should return the |
| 1009 number of bytes of provided input, and a pointer to that input in buf. If |
| 1010 there is no input available, in() must return zero--buf is ignored in that |
| 1011 case--and inflateBack() will return a buffer error. inflateBack() will call |
| 1012 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() |
| 1013 should return zero on success, or non-zero on failure. If out() returns |
| 1014 non-zero, inflateBack() will return with an error. Neither in() nor out() |
| 1015 are permitted to change the contents of the window provided to |
| 1016 inflateBackInit(), which is also the buffer that out() uses to write from. |
| 1017 The length written by out() will be at most the window size. Any non-zero |
| 1018 amount of input may be provided by in(). |
| 1019 |
| 1020 For convenience, inflateBack() can be provided input on the first call by |
| 1021 setting strm->next_in and strm->avail_in. If that input is exhausted, then |
| 1022 in() will be called. Therefore strm->next_in must be initialized before |
| 1023 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called |
| 1024 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in |
| 1025 must also be initialized, and then if strm->avail_in is not zero, input will |
| 1026 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
| 1027 |
| 1028 The in_desc and out_desc parameters of inflateBack() is passed as the |
| 1029 first parameter of in() and out() respectively when they are called. These |
| 1030 descriptors can be optionally used to pass any information that the caller- |
| 1031 supplied in() and out() functions need to do their job. |
| 1032 |
| 1033 On return, inflateBack() will set strm->next_in and strm->avail_in to |
| 1034 pass back any unused input that was provided by the last in() call. The |
| 1035 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR |
| 1036 if in() or out() returned an error, Z_DATA_ERROR if there was a format error |
| 1037 in the deflate stream (in which case strm->msg is set to indicate the nature |
| 1038 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. |
| 1039 In the case of Z_BUF_ERROR, an input or output error can be distinguished |
| 1040 using strm->next_in which will be Z_NULL only if in() returned an error. If |
| 1041 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning |
| 1042 non-zero. (in() will always be called before out(), so strm->next_in is |
| 1043 assured to be defined if out() returns non-zero.) Note that inflateBack() |
| 1044 cannot return Z_OK. |
| 1045 */ |
| 1046 |
| 1047 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); |
| 1048 /* |
| 1049 All memory allocated by inflateBackInit() is freed. |
| 1050 |
| 1051 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream |
| 1052 state was inconsistent. |
| 1053 */ |
| 1054 |
| 1055 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); |
| 1056 /* Return flags indicating compile-time options. |
| 1057 |
| 1058 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: |
| 1059 1.0: size of uInt |
| 1060 3.2: size of uLong |
| 1061 5.4: size of voidpf (pointer) |
| 1062 7.6: size of z_off_t |
| 1063 |
| 1064 Compiler, assembler, and debug options: |
| 1065 8: DEBUG |
| 1066 9: ASMV or ASMINF -- use ASM code |
| 1067 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention |
| 1068 11: 0 (reserved) |
| 1069 |
| 1070 One-time table building (smaller code, but not thread-safe if true): |
| 1071 12: BUILDFIXED -- build static block decoding tables when needed |
| 1072 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed |
| 1073 14,15: 0 (reserved) |
| 1074 |
| 1075 Library content (indicates missing functionality): |
| 1076 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking |
| 1077 deflate code when not needed) |
| 1078 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect |
| 1079 and decode gzip streams (to avoid linking crc code) |
| 1080 18-19: 0 (reserved) |
| 1081 |
| 1082 Operation variations (changes in library functionality): |
| 1083 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate |
| 1084 21: FASTEST -- deflate algorithm with only one, lowest compression level |
| 1085 22,23: 0 (reserved) |
| 1086 |
| 1087 The sprintf variant used by gzprintf (zero is best): |
| 1088 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format |
| 1089 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! |
| 1090 26: 0 = returns value, 1 = void -- 1 means inferred string length returned |
| 1091 |
| 1092 Remainder: |
| 1093 27-31: 0 (reserved) |
| 1094 */ |
| 1095 |
| 1096 |
| 1097 /* utility functions */ |
| 1098 |
| 1099 /* |
| 1100 The following utility functions are implemented on top of the basic |
| 1101 stream-oriented functions. To simplify the interface, some default options |
| 1102 are assumed (compression level and memory usage, standard memory allocation |
| 1103 functions). The source code of these utility functions can be modified if |
| 1104 you need special options. |
| 1105 */ |
| 1106 |
| 1107 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, |
| 1108 const Bytef *source, uLong sourceLen)); |
| 1109 /* |
| 1110 Compresses the source buffer into the destination buffer. sourceLen is |
| 1111 the byte length of the source buffer. Upon entry, destLen is the total size |
| 1112 of the destination buffer, which must be at least the value returned by |
| 1113 compressBound(sourceLen). Upon exit, destLen is the actual size of the |
| 1114 compressed buffer. |
| 1115 |
| 1116 compress returns Z_OK if success, Z_MEM_ERROR if there was not |
| 1117 enough memory, Z_BUF_ERROR if there was not enough room in the output |
| 1118 buffer. |
| 1119 */ |
| 1120 |
| 1121 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, |
| 1122 const Bytef *source, uLong sourceLen, |
| 1123 int level)); |
| 1124 /* |
| 1125 Compresses the source buffer into the destination buffer. The level |
| 1126 parameter has the same meaning as in deflateInit. sourceLen is the byte |
| 1127 length of the source buffer. Upon entry, destLen is the total size of the |
| 1128 destination buffer, which must be at least the value returned by |
| 1129 compressBound(sourceLen). Upon exit, destLen is the actual size of the |
| 1130 compressed buffer. |
| 1131 |
| 1132 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 1133 memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
| 1134 Z_STREAM_ERROR if the level parameter is invalid. |
| 1135 */ |
| 1136 |
| 1137 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); |
| 1138 /* |
| 1139 compressBound() returns an upper bound on the compressed size after |
| 1140 compress() or compress2() on sourceLen bytes. It would be used before a |
| 1141 compress() or compress2() call to allocate the destination buffer. |
| 1142 */ |
| 1143 |
| 1144 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, |
| 1145 const Bytef *source, uLong sourceLen)); |
| 1146 /* |
| 1147 Decompresses the source buffer into the destination buffer. sourceLen is |
| 1148 the byte length of the source buffer. Upon entry, destLen is the total size |
| 1149 of the destination buffer, which must be large enough to hold the entire |
| 1150 uncompressed data. (The size of the uncompressed data must have been saved |
| 1151 previously by the compressor and transmitted to the decompressor by some |
| 1152 mechanism outside the scope of this compression library.) Upon exit, destLen |
| 1153 is the actual size of the uncompressed buffer. |
| 1154 |
| 1155 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
| 1156 enough memory, Z_BUF_ERROR if there was not enough room in the output |
| 1157 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. |
| 1158 */ |
| 1159 |
| 1160 |
| 1161 /* gzip file access functions */ |
| 1162 |
| 1163 /* |
| 1164 This library supports reading and writing files in gzip (.gz) format with |
| 1165 an interface similar to that of stdio, using the functions that start with |
| 1166 "gz". The gzip format is different from the zlib format. gzip is a gzip |
| 1167 wrapper, documented in RFC 1952, wrapped around a deflate stream. |
| 1168 */ |
| 1169 |
| 1170 typedef voidp gzFile; /* opaque gzip file descriptor */ |
| 1171 |
| 1172 /* |
| 1173 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
| 1174 |
| 1175 Opens a gzip (.gz) file for reading or writing. The mode parameter is as |
| 1176 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or |
| 1177 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only |
| 1178 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' |
| 1179 for fixed code compression as in "wb9F". (See the description of |
| 1180 deflateInit2 for more information about the strategy parameter.) Also "a" |
| 1181 can be used instead of "w" to request that the gzip stream that will be |
| 1182 written be appended to the file. "+" will result in an error, since reading |
| 1183 and writing to the same gzip file is not supported. |
| 1184 |
| 1185 gzopen can be used to read a file which is not in gzip format; in this |
| 1186 case gzread will directly read from the file without decompression. |
| 1187 |
| 1188 gzopen returns NULL if the file could not be opened, if there was |
| 1189 insufficient memory to allocate the gzFile state, or if an invalid mode was |
| 1190 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). |
| 1191 errno can be checked to determine if the reason gzopen failed was that the |
| 1192 file could not be opened. |
| 1193 */ |
| 1194 |
| 1195 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
| 1196 /* |
| 1197 gzdopen associates a gzFile with the file descriptor fd. File descriptors |
| 1198 are obtained from calls like open, dup, creat, pipe or fileno (if the file |
| 1199 has been previously opened with fopen). The mode parameter is as in gzopen. |
| 1200 |
| 1201 The next call of gzclose on the returned gzFile will also close the file |
| 1202 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor |
| 1203 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, |
| 1204 mode);. The duplicated descriptor should be saved to avoid a leak, since |
| 1205 gzdopen does not close fd if it fails. |
| 1206 |
| 1207 gzdopen returns NULL if there was insufficient memory to allocate the |
| 1208 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not |
| 1209 provided, or '+' was provided), or if fd is -1. The file descriptor is not |
| 1210 used until the next gz* read, write, seek, or close operation, so gzdopen |
| 1211 will not detect if fd is invalid (unless fd is -1). |
| 1212 */ |
| 1213 |
| 1214 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); |
| 1215 /* |
| 1216 Set the internal buffer size used by this library's functions. The |
| 1217 default buffer size is 8192 bytes. This function must be called after |
| 1218 gzopen() or gzdopen(), and before any other calls that read or write the |
| 1219 file. The buffer memory allocation is always deferred to the first read or |
| 1220 write. Two buffers are allocated, either both of the specified size when |
| 1221 writing, or one of the specified size and the other twice that size when |
| 1222 reading. A larger buffer size of, for example, 64K or 128K bytes will |
| 1223 noticeably increase the speed of decompression (reading). |
| 1224 |
| 1225 The new buffer size also affects the maximum length for gzprintf(). |
| 1226 |
| 1227 gzbuffer() returns 0 on success, or -1 on failure, such as being called |
| 1228 too late. |
| 1229 */ |
| 1230 |
| 1231 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); |
| 1232 /* |
| 1233 Dynamically update the compression level or strategy. See the description |
| 1234 of deflateInit2 for the meaning of these parameters. |
| 1235 |
| 1236 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
| 1237 opened for writing. |
| 1238 */ |
| 1239 |
| 1240 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
| 1241 /* |
| 1242 Reads the given number of uncompressed bytes from the compressed file. If |
| 1243 the input file was not in gzip format, gzread copies the given number of |
| 1244 bytes into the buffer. |
| 1245 |
| 1246 After reaching the end of a gzip stream in the input, gzread will continue |
| 1247 to read, looking for another gzip stream, or failing that, reading the rest |
| 1248 of the input file directly without decompression. The entire input file |
| 1249 will be read if gzread is called until it returns less than the requested |
| 1250 len. |
| 1251 |
| 1252 gzread returns the number of uncompressed bytes actually read, less than |
| 1253 len for end of file, or -1 for error. |
| 1254 */ |
| 1255 |
| 1256 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
| 1257 voidpc buf, unsigned len)); |
| 1258 /* |
| 1259 Writes the given number of uncompressed bytes into the compressed file. |
| 1260 gzwrite returns the number of uncompressed bytes written or 0 in case of |
| 1261 error. |
| 1262 */ |
| 1263 |
| 1264 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
| 1265 /* |
| 1266 Converts, formats, and writes the arguments to the compressed file under |
| 1267 control of the format string, as in fprintf. gzprintf returns the number of |
| 1268 uncompressed bytes actually written, or 0 in case of error. The number of |
| 1269 uncompressed bytes written is limited to 8191, or one less than the buffer |
| 1270 size given to gzbuffer(). The caller should assure that this limit is not |
| 1271 exceeded. If it is exceeded, then gzprintf() will return an error (0) with |
| 1272 nothing written. In this case, there may also be a buffer overflow with |
| 1273 unpredictable consequences, which is possible only if zlib was compiled with |
| 1274 the insecure functions sprintf() or vsprintf() because the secure snprintf() |
| 1275 or vsnprintf() functions were not available. This can be determined using |
| 1276 zlibCompileFlags(). |
| 1277 */ |
| 1278 |
| 1279 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); |
| 1280 /* |
| 1281 Writes the given null-terminated string to the compressed file, excluding |
| 1282 the terminating null character. |
| 1283 |
| 1284 gzputs returns the number of characters written, or -1 in case of error. |
| 1285 */ |
| 1286 |
| 1287 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); |
| 1288 /* |
| 1289 Reads bytes from the compressed file until len-1 characters are read, or a |
| 1290 newline character is read and transferred to buf, or an end-of-file |
| 1291 condition is encountered. If any characters are read or if len == 1, the |
| 1292 string is terminated with a null character. If no characters are read due |
| 1293 to an end-of-file or len < 1, then the buffer is left untouched. |
| 1294 |
| 1295 gzgets returns buf which is a null-terminated string, or it returns NULL |
| 1296 for end-of-file or in case of error. If there was an error, the contents at |
| 1297 buf are indeterminate. |
| 1298 */ |
| 1299 |
| 1300 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
| 1301 /* |
| 1302 Writes c, converted to an unsigned char, into the compressed file. gzputc |
| 1303 returns the value that was written, or -1 in case of error. |
| 1304 */ |
| 1305 |
| 1306 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
| 1307 /* |
| 1308 Reads one byte from the compressed file. gzgetc returns this byte or -1 |
| 1309 in case of end of file or error. |
| 1310 */ |
| 1311 |
| 1312 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); |
| 1313 /* |
| 1314 Push one character back onto the stream to be read as the first character |
| 1315 on the next read. At least one character of push-back is allowed. |
| 1316 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will |
| 1317 fail if c is -1, and may fail if a character has been pushed but not read |
| 1318 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the |
| 1319 output buffer size of pushed characters is allowed. (See gzbuffer above.) |
| 1320 The pushed character will be discarded if the stream is repositioned with |
| 1321 gzseek() or gzrewind(). |
| 1322 */ |
| 1323 |
| 1324 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
| 1325 /* |
| 1326 Flushes all pending output into the compressed file. The parameter flush |
| 1327 is as in the deflate() function. The return value is the zlib error number |
| 1328 (see function gzerror below). gzflush is only permitted when writing. |
| 1329 |
| 1330 If the flush parameter is Z_FINISH, the remaining data is written and the |
| 1331 gzip stream is completed in the output. If gzwrite() is called again, a new |
| 1332 gzip stream will be started in the output. gzread() is able to read such |
| 1333 concatented gzip streams. |
| 1334 |
| 1335 gzflush should be called only when strictly necessary because it will |
| 1336 degrade compression if called too often. |
| 1337 */ |
| 1338 |
| 1339 /* |
| 1340 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
| 1341 z_off_t offset, int whence)); |
| 1342 |
| 1343 Sets the starting position for the next gzread or gzwrite on the given |
| 1344 compressed file. The offset represents a number of bytes in the |
| 1345 uncompressed data stream. The whence parameter is defined as in lseek(2); |
| 1346 the value SEEK_END is not supported. |
| 1347 |
| 1348 If the file is opened for reading, this function is emulated but can be |
| 1349 extremely slow. If the file is opened for writing, only forward seeks are |
| 1350 supported; gzseek then compresses a sequence of zeroes up to the new |
| 1351 starting position. |
| 1352 |
| 1353 gzseek returns the resulting offset location as measured in bytes from |
| 1354 the beginning of the uncompressed stream, or -1 in case of error, in |
| 1355 particular if the file is opened for writing and the new starting position |
| 1356 would be before the current position. |
| 1357 */ |
| 1358 |
| 1359 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); |
| 1360 /* |
| 1361 Rewinds the given file. This function is supported only for reading. |
| 1362 |
| 1363 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
| 1364 */ |
| 1365 |
| 1366 /* |
| 1367 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
| 1368 |
| 1369 Returns the starting position for the next gzread or gzwrite on the given |
| 1370 compressed file. This position represents a number of bytes in the |
| 1371 uncompressed data stream, and is zero when starting, even if appending or |
| 1372 reading a gzip stream from the middle of a file using gzdopen(). |
| 1373 |
| 1374 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
| 1375 */ |
| 1376 |
| 1377 /* |
| 1378 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); |
| 1379 |
| 1380 Returns the current offset in the file being read or written. This offset |
| 1381 includes the count of bytes that precede the gzip stream, for example when |
| 1382 appending or when using gzdopen() for reading. When reading, the offset |
| 1383 does not include as yet unused buffered input. This information can be used |
| 1384 for a progress indicator. On error, gzoffset() returns -1. |
| 1385 */ |
| 1386 |
| 1387 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); |
| 1388 /* |
| 1389 Returns true (1) if the end-of-file indicator has been set while reading, |
| 1390 false (0) otherwise. Note that the end-of-file indicator is set only if the |
| 1391 read tried to go past the end of the input, but came up short. Therefore, |
| 1392 just like feof(), gzeof() may return false even if there is no more data to |
| 1393 read, in the event that the last read request was for the exact number of |
| 1394 bytes remaining in the input file. This will happen if the input file size |
| 1395 is an exact multiple of the buffer size. |
| 1396 |
| 1397 If gzeof() returns true, then the read functions will return no more data, |
| 1398 unless the end-of-file indicator is reset by gzclearerr() and the input file |
| 1399 has grown since the previous end of file was detected. |
| 1400 */ |
| 1401 |
| 1402 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); |
| 1403 /* |
| 1404 Returns true (1) if file is being copied directly while reading, or false |
| 1405 (0) if file is a gzip stream being decompressed. This state can change from |
| 1406 false to true while reading the input file if the end of a gzip stream is |
| 1407 reached, but is followed by data that is not another gzip stream. |
| 1408 |
| 1409 If the input file is empty, gzdirect() will return true, since the input |
| 1410 does not contain a gzip stream. |
| 1411 |
| 1412 If gzdirect() is used immediately after gzopen() or gzdopen() it will |
| 1413 cause buffers to be allocated to allow reading the file to determine if it |
| 1414 is a gzip file. Therefore if gzbuffer() is used, it should be called before |
| 1415 gzdirect(). |
| 1416 */ |
| 1417 |
| 1418 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
| 1419 /* |
| 1420 Flushes all pending output if necessary, closes the compressed file and |
| 1421 deallocates the (de)compression state. Note that once file is closed, you |
| 1422 cannot call gzerror with file, since its structures have been deallocated. |
| 1423 gzclose must not be called more than once on the same file, just as free |
| 1424 must not be called more than once on the same allocation. |
| 1425 |
| 1426 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a |
| 1427 file operation error, or Z_OK on success. |
| 1428 */ |
| 1429 |
| 1430 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); |
| 1431 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); |
| 1432 /* |
| 1433 Same as gzclose(), but gzclose_r() is only for use when reading, and |
| 1434 gzclose_w() is only for use when writing or appending. The advantage to |
| 1435 using these instead of gzclose() is that they avoid linking in zlib |
| 1436 compression or decompression code that is not used when only reading or only |
| 1437 writing respectively. If gzclose() is used, then both compression and |
| 1438 decompression code will be included the application when linking to a static |
| 1439 zlib library. |
| 1440 */ |
| 1441 |
| 1442 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); |
| 1443 /* |
| 1444 Returns the error message for the last error which occurred on the given |
| 1445 compressed file. errnum is set to zlib error number. If an error occurred |
| 1446 in the file system and not in the compression library, errnum is set to |
| 1447 Z_ERRNO and the application may consult errno to get the exact error code. |
| 1448 |
| 1449 The application must not modify the returned string. Future calls to |
| 1450 this function may invalidate the previously returned string. If file is |
| 1451 closed, then the string previously returned by gzerror will no longer be |
| 1452 available. |
| 1453 |
| 1454 gzerror() should be used to distinguish errors from end-of-file for those |
| 1455 functions above that do not distinguish those cases in their return values. |
| 1456 */ |
| 1457 |
| 1458 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); |
| 1459 /* |
| 1460 Clears the error and end-of-file flags for file. This is analogous to the |
| 1461 clearerr() function in stdio. This is useful for continuing to read a gzip |
| 1462 file that is being written concurrently. |
| 1463 */ |
| 1464 |
| 1465 |
| 1466 /* checksum functions */ |
| 1467 |
| 1468 /* |
| 1469 These functions are not related to compression but are exported |
| 1470 anyway because they might be useful in applications using the compression |
| 1471 library. |
| 1472 */ |
| 1473 |
| 1474 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
| 1475 /* |
| 1476 Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
| 1477 return the updated checksum. If buf is Z_NULL, this function returns the |
| 1478 required initial value for the checksum. |
| 1479 |
| 1480 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
| 1481 much faster. |
| 1482 |
| 1483 Usage example: |
| 1484 |
| 1485 uLong adler = adler32(0L, Z_NULL, 0); |
| 1486 |
| 1487 while (read_buffer(buffer, length) != EOF) { |
| 1488 adler = adler32(adler, buffer, length); |
| 1489 } |
| 1490 if (adler != original_adler) error(); |
| 1491 */ |
| 1492 |
| 1493 /* |
| 1494 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, |
| 1495 z_off_t len2)); |
| 1496 |
| 1497 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 |
| 1498 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for |
| 1499 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of |
| 1500 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. |
| 1501 */ |
| 1502 |
| 1503 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
| 1504 /* |
| 1505 Update a running CRC-32 with the bytes buf[0..len-1] and return the |
| 1506 updated CRC-32. If buf is Z_NULL, this function returns the required |
| 1507 initial value for the for the crc. Pre- and post-conditioning (one's |
| 1508 complement) is performed within this function so it shouldn't be done by the |
| 1509 application. |
| 1510 |
| 1511 Usage example: |
| 1512 |
| 1513 uLong crc = crc32(0L, Z_NULL, 0); |
| 1514 |
| 1515 while (read_buffer(buffer, length) != EOF) { |
| 1516 crc = crc32(crc, buffer, length); |
| 1517 } |
| 1518 if (crc != original_crc) error(); |
| 1519 */ |
| 1520 |
| 1521 /* |
| 1522 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); |
| 1523 |
| 1524 Combine two CRC-32 check values into one. For two sequences of bytes, |
| 1525 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were |
| 1526 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 |
| 1527 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and |
| 1528 len2. |
| 1529 */ |
| 1530 |
| 1531 |
| 1532 /* various hacks, don't look :) */ |
| 1533 |
| 1534 /* deflateInit and inflateInit are macros to allow checking the zlib version |
| 1535 * and the compiler's view of z_stream: |
| 1536 */ |
| 1537 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, |
| 1538 const char *version, int stream_size)); |
| 1539 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, |
| 1540 const char *version, int stream_size)); |
| 1541 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, |
| 1542 int windowBits, int memLevel, |
| 1543 int strategy, const char *version, |
| 1544 int stream_size)); |
| 1545 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, |
| 1546 const char *version, int stream_size)); |
| 1547 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, |
| 1548 unsigned char FAR *window, |
| 1549 const char *version, |
| 1550 int stream_size)); |
| 1551 #define deflateInit(strm, level) \ |
| 1552 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
| 1553 #define inflateInit(strm) \ |
| 1554 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
| 1555 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
| 1556 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
| 1557 (strategy), ZLIB_VERSION, sizeof(z_stream)) |
| 1558 #define inflateInit2(strm, windowBits) \ |
| 1559 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
| 1560 #define inflateBackInit(strm, windowBits, window) \ |
| 1561 inflateBackInit_((strm), (windowBits), (window), \ |
| 1562 ZLIB_VERSION, sizeof(z_stream)) |
| 1563 |
| 1564 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or |
| 1565 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if |
| 1566 * both are true, the application gets the *64 functions, and the regular |
| 1567 * functions are changed to 64 bits) -- in case these are set on systems |
| 1568 * without large file support, _LFS64_LARGEFILE must also be true |
| 1569 */ |
| 1570 #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0 |
| 1571 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); |
| 1572 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); |
| 1573 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); |
| 1574 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); |
| 1575 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); |
| 1576 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); |
| 1577 #endif |
| 1578 |
| 1579 #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0 |
| 1580 # ifdef gzopen |
| 1581 # undef gzopen |
| 1582 # endif |
| 1583 # define gzopen gzopen64 |
| 1584 # ifdef gzseek |
| 1585 # undef gzseek |
| 1586 # endif |
| 1587 # define gzseek gzseek64 |
| 1588 # ifdef gztell |
| 1589 # undef gztell |
| 1590 # endif |
| 1591 # define gztell gztell64 |
| 1592 # ifdef gzoffset |
| 1593 # undef gzoffset |
| 1594 # endif |
| 1595 # define gzoffset gzoffset64 |
| 1596 # ifdef adler32_combine |
| 1597 # undef adler32_combine |
| 1598 # endif |
| 1599 # define adler32_combine adler32_combine64 |
| 1600 # ifdef crc32_combine |
| 1601 # undef crc32_combine |
| 1602 # endif |
| 1603 # define crc32_combine crc32_combine64 |
| 1604 # ifdef _LARGEFILE64_SOURCE |
| 1605 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); |
| 1606 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); |
| 1607 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); |
| 1608 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); |
| 1609 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); |
| 1610 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); |
| 1611 # else |
| 1612 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); |
| 1613 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); |
| 1614 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); |
| 1615 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); |
| 1616 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); |
| 1617 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); |
| 1618 # endif |
| 1619 #else |
| 1620 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); |
| 1621 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); |
| 1622 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); |
| 1623 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); |
| 1624 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); |
| 1625 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); |
| 1626 #endif |
| 1627 |
| 1628 /* hack for buggy compilers */ |
| 1629 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
| 1630 struct internal_state {int dummy;}; |
| 1631 #endif |
| 1632 |
| 1633 /* undocumented functions */ |
| 1634 ZEXTERN const char * ZEXPORT zError OF((int)); |
| 1635 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); |
| 1636 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
| 1637 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); |
| 1638 |
| 1639 #ifdef __cplusplus |
| 1640 } |
| 1641 #endif |
| 1642 |
| 1643 #endif /* ZLIB_H */ |
OLD | NEW |