| 1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
|---|---|
| 2 | version 1.3.2, February 17th, 2026 |
| 3 | |
| 4 | Copyright (C) 1995-2026 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 at https://datatracker.ietf.org/doc/html/rfc1950 |
| 28 | (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). |
| 29 | */ |
| 30 | |
| 31 | #ifndef ZLIB_H |
| 32 | #define ZLIB_H |
| 33 | |
| 34 | #ifdef ZLIB_BUILD |
| 35 | # include <zconf.h> |
| 36 | #else |
| 37 | # include "zconf.h" |
| 38 | #endif |
| 39 | |
| 40 | #ifdef __cplusplus |
| 41 | extern "C"{ |
| 42 | #endif |
| 43 | |
| 44 | #define ZLIB_VERSION "1.3.2" |
| 45 | #define ZLIB_VERNUM 0x1320 |
| 46 | #define ZLIB_VER_MAJOR 1 |
| 47 | #define ZLIB_VER_MINOR 3 |
| 48 | #define ZLIB_VER_REVISION 2 |
| 49 | #define ZLIB_VER_SUBREVISION 0 |
| 50 | |
| 51 | /* |
| 52 | The 'zlib' compression library provides in-memory compression and |
| 53 | decompression functions, including integrity checks of the uncompressed data. |
| 54 | This version of the library supports only one compression method (deflation) |
| 55 | but other algorithms will be added later and will have the same stream |
| 56 | interface. |
| 57 | |
| 58 | Compression can be done in a single step if the buffers are large enough, |
| 59 | or can be done by repeated calls of the compression function. In the latter |
| 60 | case, the application must provide more input and/or consume the output |
| 61 | (providing more output space) before each call. |
| 62 | |
| 63 | The compressed data format used by default by the in-memory functions is |
| 64 | the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped |
| 65 | around a deflate stream, which is itself documented in RFC 1951. |
| 66 | |
| 67 | The library also supports reading and writing files in gzip (.gz) format |
| 68 | with an interface similar to that of stdio using the functions that start |
| 69 | with "gz". The gzip format is different from the zlib format. gzip is a |
| 70 | gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. |
| 71 | |
| 72 | This library can optionally read and write gzip and raw deflate streams in |
| 73 | memory as well. |
| 74 | |
| 75 | The zlib format was designed to be compact and fast for use in memory |
| 76 | and on communications channels. The gzip format was designed for single- |
| 77 | file compression on file systems, has a larger header than zlib to maintain |
| 78 | directory information, and uses a different, slower check method than zlib. |
| 79 | |
| 80 | The library does not install any signal handler. The decoder checks |
| 81 | the consistency of the compressed data, so the library should never crash |
| 82 | even in the case of corrupted input. |
| 83 | */ |
| 84 | |
| 85 | typedef voidpf (*alloc_func)(voidpf opaque, uInt items, uInt size); |
| 86 | typedef void (*free_func)(voidpf opaque, voidpf address); |
| 87 | |
| 88 | struct internal_state; |
| 89 | |
| 90 | typedef struct z_stream_s { |
| 91 | z_const Bytef *next_in; /* next input byte */ |
| 92 | uInt avail_in; /* number of bytes available at next_in */ |
| 93 | uLong total_in; /* total number of input bytes read so far */ |
| 94 | |
| 95 | Bytef *next_out; /* next output byte will go here */ |
| 96 | uInt avail_out; /* remaining free space at next_out */ |
| 97 | uLong total_out; /* total number of bytes output so far */ |
| 98 | |
| 99 | z_const char *msg; /* last error message, NULL if no error */ |
| 100 | struct internal_state FAR *state; /* not visible by applications */ |
| 101 | |
| 102 | alloc_func zalloc; /* used to allocate the internal state */ |
| 103 | free_func zfree; /* used to free the internal state */ |
| 104 | voidpf opaque; /* private data object passed to zalloc and zfree */ |
| 105 | |
| 106 | int data_type; /* best guess about the data type: binary or text |
| 107 | for deflate, or the decoding state for inflate */ |
| 108 | uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */ |
| 109 | uLong reserved; /* reserved for future use */ |
| 110 | } z_stream; |
| 111 | |
| 112 | typedef z_stream FAR *z_streamp; |
| 113 | |
| 114 | /* |
| 115 | gzip header information passed to and from zlib routines. See RFC 1952 |
| 116 | for more details on the meanings of these fields. |
| 117 | */ |
| 118 | typedef struct gz_header_s { |
| 119 | int text; /* true if compressed data believed to be text */ |
| 120 | uLong time; /* modification time */ |
| 121 | int xflags; /* extra flags (not used when writing a gzip file) */ |
| 122 | int os; /* operating system */ |
| 123 | Bytef *extra; /* pointer to extra field or Z_NULL if none */ |
| 124 | uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ |
| 125 | uInt extra_max; /* space at extra (only when reading header) */ |
| 126 | Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ |
| 127 | uInt name_max; /* space at name (only when reading header) */ |
| 128 | Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ |
| 129 | uInt comm_max; /* space at comment (only when reading header) */ |
| 130 | int hcrc; /* true if there was or will be a header crc */ |
| 131 | int done; /* true when done reading gzip header (not used |
| 132 | when writing a gzip file) */ |
| 133 | } gz_header; |
| 134 | |
| 135 | typedef gz_header FAR *gz_headerp; |
| 136 | |
| 137 | /* |
| 138 | The application must update next_in and avail_in when avail_in has dropped |
| 139 | to zero. It must update next_out and avail_out when avail_out has dropped |
| 140 | to zero. The application must initialize zalloc, zfree and opaque before |
| 141 | calling the init function. All other fields are set by the compression |
| 142 | library and must not be updated by the application. |
| 143 | |
| 144 | The opaque value provided by the application will be passed as the first |
| 145 | parameter for calls of zalloc and zfree. This can be useful for custom |
| 146 | memory management. The compression library attaches no meaning to the |
| 147 | opaque value. |
| 148 | |
| 149 | zalloc must return Z_NULL if there is not enough memory for the object. |
| 150 | If zlib is used in a multi-threaded application, zalloc and zfree must be |
| 151 | thread safe. In that case, zlib is thread-safe. When zalloc and zfree are |
| 152 | Z_NULL on entry to the initialization function, they are set to internal |
| 153 | routines that use the standard library functions malloc() and free(). |
| 154 | |
| 155 | On 16-bit systems, the functions zalloc and zfree must be able to allocate |
| 156 | exactly 65536 bytes, but will not be required to allocate more than this if |
| 157 | the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers |
| 158 | returned by zalloc for objects of exactly 65536 bytes *must* have their |
| 159 | offset normalized to zero. The default allocation function provided by this |
| 160 | library ensures this (see zutil.c). To reduce memory requirements and avoid |
| 161 | any allocation of 64K objects, at the expense of compression ratio, compile |
| 162 | the library with -DMAX_WBITS=14 (see zconf.h). |
| 163 | |
| 164 | The fields total_in and total_out can be used for statistics or progress |
| 165 | reports. After compression, total_in holds the total size of the |
| 166 | uncompressed data and may be saved for use by the decompressor (particularly |
| 167 | if the decompressor wants to decompress everything in a single step). |
| 168 | */ |
| 169 | |
| 170 | /* constants */ |
| 171 | |
| 172 | #define Z_NO_FLUSH 0 |
| 173 | #define Z_PARTIAL_FLUSH 1 |
| 174 | #define Z_SYNC_FLUSH 2 |
| 175 | #define Z_FULL_FLUSH 3 |
| 176 | #define Z_FINISH 4 |
| 177 | #define Z_BLOCK 5 |
| 178 | #define Z_TREES 6 |
| 179 | /* Allowed flush values; see deflate() and inflate() below for details */ |
| 180 | |
| 181 | #define Z_OK 0 |
| 182 | #define Z_STREAM_END 1 |
| 183 | #define Z_NEED_DICT 2 |
| 184 | #define Z_ERRNO (-1) |
| 185 | #define Z_STREAM_ERROR (-2) |
| 186 | #define Z_DATA_ERROR (-3) |
| 187 | #define Z_MEM_ERROR (-4) |
| 188 | #define Z_BUF_ERROR (-5) |
| 189 | #define Z_VERSION_ERROR (-6) |
| 190 | /* Return codes for the compression/decompression functions. Negative values |
| 191 | * are errors, positive values are used for special but normal events. |
| 192 | */ |
| 193 | |
| 194 | #define Z_NO_COMPRESSION 0 |
| 195 | #define Z_BEST_SPEED 1 |
| 196 | #define Z_BEST_COMPRESSION 9 |
| 197 | #define Z_DEFAULT_COMPRESSION (-1) |
| 198 | /* compression levels */ |
| 199 | |
| 200 | #define Z_FILTERED 1 |
| 201 | #define Z_HUFFMAN_ONLY 2 |
| 202 | #define Z_RLE 3 |
| 203 | #define Z_FIXED 4 |
| 204 | #define Z_DEFAULT_STRATEGY 0 |
| 205 | /* compression strategy; see deflateInit2() below for details */ |
| 206 | |
| 207 | #define Z_BINARY 0 |
| 208 | #define Z_TEXT 1 |
| 209 | #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ |
| 210 | #define Z_UNKNOWN 2 |
| 211 | /* Possible values of the data_type field for deflate() */ |
| 212 | |
| 213 | #define Z_DEFLATED 8 |
| 214 | /* The deflate compression method (the only one supported in this version) */ |
| 215 | |
| 216 | #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
| 217 | |
| 218 | #define zlib_version zlibVersion() |
| 219 | /* for compatibility with versions < 1.0.2 */ |
| 220 | |
| 221 | |
| 222 | /* basic functions */ |
| 223 | |
| 224 | ZEXTERN const char * ZEXPORT zlibVersion(void); |
| 225 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
| 226 | If the first character differs, the library code actually used is not |
| 227 | compatible with the zlib.h header file used by the application. This check |
| 228 | is automatically made by deflateInit and inflateInit. |
| 229 | */ |
| 230 | |
| 231 | /* |
| 232 | ZEXTERN int ZEXPORT deflateInit(z_streamp strm, int level); |
| 233 | |
| 234 | Initializes the internal stream state for compression. The fields |
| 235 | zalloc, zfree and opaque must be initialized before by the caller. If |
| 236 | zalloc and zfree are set to Z_NULL, deflateInit updates them to use default |
| 237 | allocation functions. total_in, total_out, adler, and msg are initialized. |
| 238 | |
| 239 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
| 240 | 1 gives best speed, 9 gives best compression, 0 gives no compression at all |
| 241 | (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION |
| 242 | requests a default compromise between speed and compression (currently |
| 243 | equivalent to level 6). |
| 244 | |
| 245 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 246 | memory, Z_STREAM_ERROR if level is not a valid compression level, or |
| 247 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
| 248 | with the version assumed by the caller (ZLIB_VERSION). msg is set to null |
| 249 | if there is no error message. deflateInit does not perform any compression: |
| 250 | this will be done by deflate(). |
| 251 | */ |
| 252 | |
| 253 | |
| 254 | ZEXTERN int ZEXPORT deflate(z_streamp strm, int flush); |
| 255 | /* |
| 256 | deflate compresses as much data as possible, and stops when the input |
| 257 | buffer becomes empty or the output buffer becomes full. It may introduce |
| 258 | some output latency (reading input without producing any output) except when |
| 259 | forced to flush. |
| 260 | |
| 261 | The detailed semantics are as follows. deflate performs one or both of the |
| 262 | following actions: |
| 263 | |
| 264 | - Compress more input starting at next_in and update next_in and avail_in |
| 265 | accordingly. If not all input can be processed (because there is not |
| 266 | enough room in the output buffer), next_in and avail_in are updated and |
| 267 | processing will resume at this point for the next call of deflate(). |
| 268 | |
| 269 | - Generate more output starting at next_out and update next_out and avail_out |
| 270 | accordingly. This action is forced if the parameter flush is non zero. |
| 271 | Forcing flush frequently degrades the compression ratio, so this parameter |
| 272 | should be set only when necessary. Some output may be provided even if |
| 273 | flush is zero. |
| 274 | |
| 275 | Before the call of deflate(), the application should ensure that at least |
| 276 | one of the actions is possible, by providing more input and/or consuming more |
| 277 | output, and updating avail_in or avail_out accordingly; avail_out should |
| 278 | never be zero before the call. The application can consume the compressed |
| 279 | output when it wants, for example when the output buffer is full (avail_out |
| 280 | == 0), or after each call of deflate(). If deflate returns Z_OK and with |
| 281 | zero avail_out, it must be called again after making room in the output |
| 282 | buffer because there might be more output pending. See deflatePending(), |
| 283 | which can be used if desired to determine whether or not there is more output |
| 284 | in that case. |
| 285 | |
| 286 | Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to |
| 287 | decide how much data to accumulate before producing output, in order to |
| 288 | maximize compression. |
| 289 | |
| 290 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
| 291 | flushed to the output buffer and the output is aligned on a byte boundary, so |
| 292 | that the decompressor can get all input data available so far. (In |
| 293 | particular avail_in is zero after the call if enough output space has been |
| 294 | provided before the call.) Flushing may degrade compression for some |
| 295 | compression algorithms and so it should be used only when necessary. This |
| 296 | completes the current deflate block and follows it with an empty stored block |
| 297 | that is three bits plus filler bits to the next byte, followed by four bytes |
| 298 | (00 00 ff ff). |
| 299 | |
| 300 | If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the |
| 301 | output buffer, but the output is not aligned to a byte boundary. All of the |
| 302 | input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. |
| 303 | This completes the current deflate block and follows it with an empty fixed |
| 304 | codes block that is 10 bits long. This assures that enough bytes are output |
| 305 | in order for the decompressor to finish the block before the empty fixed |
| 306 | codes block. |
| 307 | |
| 308 | If flush is set to Z_BLOCK, a deflate block is completed and emitted, as |
| 309 | for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to |
| 310 | seven bits of the current block are held to be written as the next byte after |
| 311 | the next deflate block is completed. In this case, the decompressor may not |
| 312 | be provided enough bits at this point in order to complete decompression of |
| 313 | the data provided so far to the compressor. It may need to wait for the next |
| 314 | block to be emitted. This is for advanced applications that need to control |
| 315 | the emission of deflate blocks. |
| 316 | |
| 317 | If flush is set to Z_FULL_FLUSH, all output is flushed as with |
| 318 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
| 319 | restart from this point if previous compressed data has been damaged or if |
| 320 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
| 321 | compression. |
| 322 | |
| 323 | If deflate returns with avail_out == 0, this function must be called again |
| 324 | with the same value of the flush parameter and more output space (updated |
| 325 | avail_out), until the flush is complete (deflate returns with non-zero |
| 326 | avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
| 327 | avail_out is greater than six when the flush marker begins, in order to avoid |
| 328 | repeated flush markers upon calling deflate() again when avail_out == 0. |
| 329 | |
| 330 | If the parameter flush is set to Z_FINISH, pending input is processed, |
| 331 | pending output is flushed and deflate returns with Z_STREAM_END if there was |
| 332 | enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this |
| 333 | function must be called again with Z_FINISH and more output space (updated |
| 334 | avail_out) but no more input data, until it returns with Z_STREAM_END or an |
| 335 | error. After deflate has returned Z_STREAM_END, the only possible operations |
| 336 | on the stream are deflateReset or deflateEnd. |
| 337 | |
| 338 | Z_FINISH can be used in the first deflate call after deflateInit if all the |
| 339 | compression is to be done in a single step. In order to complete in one |
| 340 | call, avail_out must be at least the value returned by deflateBound (see |
| 341 | below). Then deflate is guaranteed to return Z_STREAM_END. If not enough |
| 342 | output space is provided, deflate will not return Z_STREAM_END, and it must |
| 343 | be called again as described above. |
| 344 | |
| 345 | deflate() sets strm->adler to the Adler-32 checksum of all input read |
| 346 | so far (that is, total_in bytes). If a gzip stream is being generated, then |
| 347 | strm->adler will be the CRC-32 checksum of the input read so far. (See |
| 348 | deflateInit2 below.) |
| 349 | |
| 350 | deflate() may update strm->data_type if it can make a good guess about |
| 351 | the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is |
| 352 | considered binary. This field is only for information purposes and does not |
| 353 | affect the compression algorithm in any manner. |
| 354 | |
| 355 | deflate() returns Z_OK if some progress has been made (more input |
| 356 | processed or more output produced), Z_STREAM_END if all input has been |
| 357 | consumed and all output has been produced (only when flush is set to |
| 358 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
| 359 | if next_in or next_out was Z_NULL or the state was inadvertently written over |
| 360 | by the application), or Z_BUF_ERROR if no progress is possible (for example |
| 361 | avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and |
| 362 | deflate() can be called again with more input and more output space to |
| 363 | continue compressing. |
| 364 | */ |
| 365 | |
| 366 | |
| 367 | ZEXTERN int ZEXPORT deflateEnd(z_streamp strm); |
| 368 | /* |
| 369 | All dynamically allocated data structures for this stream are freed. |
| 370 | This function discards any unprocessed input and does not flush any pending |
| 371 | output. |
| 372 | |
| 373 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
| 374 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
| 375 | prematurely (some input or output was discarded). In the error case, msg |
| 376 | may be set but then points to a static string (which must not be |
| 377 | deallocated). |
| 378 | */ |
| 379 | |
| 380 | |
| 381 | /* |
| 382 | ZEXTERN int ZEXPORT inflateInit(z_streamp strm); |
| 383 | |
| 384 | Initializes the internal stream state for decompression. The fields |
| 385 | next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
| 386 | the caller. In the current version of inflate, the provided input is not |
| 387 | read or consumed. The allocation of a sliding window will be deferred to |
| 388 | the first call of inflate (if the decompression does not complete on the |
| 389 | first call). If zalloc and zfree are set to Z_NULL, inflateInit updates |
| 390 | them to use default allocation functions. total_in, total_out, adler, and |
| 391 | msg are initialized. |
| 392 | |
| 393 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 394 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
| 395 | version assumed by the caller, or Z_STREAM_ERROR if the parameters are |
| 396 | invalid, such as a null pointer to the structure. msg is set to null if |
| 397 | there is no error message. inflateInit does not perform any decompression. |
| 398 | Actual decompression will be done by inflate(). So next_in, and avail_in, |
| 399 | next_out, and avail_out are unused and unchanged. The current |
| 400 | implementation of inflateInit() does not process any header information -- |
| 401 | that is deferred until inflate() is called. |
| 402 | */ |
| 403 | |
| 404 | |
| 405 | ZEXTERN int ZEXPORT inflate(z_streamp strm, int flush); |
| 406 | /* |
| 407 | inflate decompresses as much data as possible, and stops when the input |
| 408 | buffer becomes empty or the output buffer becomes full. It may introduce |
| 409 | some output latency (reading input without producing any output) except when |
| 410 | forced to flush. |
| 411 | |
| 412 | The detailed semantics are as follows. inflate performs one or both of the |
| 413 | following actions: |
| 414 | |
| 415 | - Decompress more input starting at next_in and update next_in and avail_in |
| 416 | accordingly. If not all input can be processed (because there is not |
| 417 | enough room in the output buffer), then next_in and avail_in are updated |
| 418 | accordingly, and processing will resume at this point for the next call of |
| 419 | inflate(). |
| 420 | |
| 421 | - Generate more output starting at next_out and update next_out and avail_out |
| 422 | accordingly. inflate() provides as much output as possible, until there is |
| 423 | no more input data or no more space in the output buffer (see below about |
| 424 | the flush parameter). |
| 425 | |
| 426 | Before the call of inflate(), the application should ensure that at least |
| 427 | one of the actions is possible, by providing more input and/or consuming more |
| 428 | output, and updating the next_* and avail_* values accordingly. If the |
| 429 | caller of inflate() does not provide both available input and available |
| 430 | output space, it is possible that there will be no progress made. The |
| 431 | application can consume the uncompressed output when it wants, for example |
| 432 | when the output buffer is full (avail_out == 0), or after each call of |
| 433 | inflate(). If inflate returns Z_OK and with zero avail_out, it must be |
| 434 | called again after making room in the output buffer because there might be |
| 435 | more output pending. |
| 436 | |
| 437 | The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, |
| 438 | Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much |
| 439 | output as possible to the output buffer. Z_BLOCK requests that inflate() |
| 440 | stop if and when it gets to the next deflate block boundary. When decoding |
| 441 | the zlib or gzip format, this will cause inflate() to return immediately |
| 442 | after the header and before the first block. When doing a raw inflate, |
| 443 | inflate() will go ahead and process the first block, and will return when it |
| 444 | gets to the end of that block, or when it runs out of data. |
| 445 | |
| 446 | The Z_BLOCK option assists in appending to or combining deflate streams. |
| 447 | To assist in this, on return inflate() always sets strm->data_type to the |
| 448 | number of unused bits in the input taken from strm->next_in, plus 64 if |
| 449 | inflate() is currently decoding the last block in the deflate stream, plus |
| 450 | 128 if inflate() returned immediately after decoding an end-of-block code or |
| 451 | decoding the complete header up to just before the first byte of the deflate |
| 452 | stream. The end-of-block will not be indicated until all of the uncompressed |
| 453 | data from that block has been written to strm->next_out. The number of |
| 454 | unused bits may in general be greater than seven, except when bit 7 of |
| 455 | data_type is set, in which case the number of unused bits will be less than |
| 456 | eight. data_type is set as noted here every time inflate() returns for all |
| 457 | flush options, and so can be used to determine the amount of currently |
| 458 | consumed input in bits. |
| 459 | |
| 460 | The Z_TREES option behaves as Z_BLOCK does, but it also returns when the |
| 461 | end of each deflate block header is reached, before any actual data in that |
| 462 | block is decoded. This allows the caller to determine the length of the |
| 463 | deflate block header for later use in random access within a deflate block. |
| 464 | 256 is added to the value of strm->data_type when inflate() returns |
| 465 | immediately after reaching the end of the deflate block header. |
| 466 | |
| 467 | inflate() should normally be called until it returns Z_STREAM_END or an |
| 468 | error. However if all decompression is to be performed in a single step (a |
| 469 | single call of inflate), the parameter flush should be set to Z_FINISH. In |
| 470 | this case all pending input is processed and all pending output is flushed; |
| 471 | avail_out must be large enough to hold all of the uncompressed data for the |
| 472 | operation to complete. (The size of the uncompressed data may have been |
| 473 | saved by the compressor for this purpose.) The use of Z_FINISH is not |
| 474 | required to perform an inflation in one step. However it may be used to |
| 475 | inform inflate that a faster approach can be used for the single inflate() |
| 476 | call. Z_FINISH also informs inflate to not maintain a sliding window if the |
| 477 | stream completes, which reduces inflate's memory footprint. If the stream |
| 478 | does not complete, either because not all of the stream is provided or not |
| 479 | enough output space is provided, then a sliding window will be allocated and |
| 480 | inflate() can be called again to continue the operation as if Z_NO_FLUSH had |
| 481 | been used. |
| 482 | |
| 483 | In this implementation, inflate() always flushes as much output as |
| 484 | possible to the output buffer, and always uses the faster approach on the |
| 485 | first call. So the effects of the flush parameter in this implementation are |
| 486 | on the return value of inflate() as noted below, when inflate() returns early |
| 487 | when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of |
| 488 | memory for a sliding window when Z_FINISH is used. |
| 489 | |
| 490 | If a preset dictionary is needed after this call (see inflateSetDictionary |
| 491 | below), inflate sets strm->adler to the Adler-32 checksum of the dictionary |
| 492 | chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
| 493 | strm->adler to the Adler-32 checksum of all output produced so far (that is, |
| 494 | total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described |
| 495 | below. At the end of the stream, inflate() checks that its computed Adler-32 |
| 496 | checksum is equal to that saved by the compressor and returns Z_STREAM_END |
| 497 | only if the checksum is correct. |
| 498 | |
| 499 | inflate() can decompress and check either zlib-wrapped or gzip-wrapped |
| 500 | deflate data. The header type is detected automatically, if requested when |
| 501 | initializing with inflateInit2(). Any information contained in the gzip |
| 502 | header is not retained unless inflateGetHeader() is used. When processing |
| 503 | gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output |
| 504 | produced so far. The CRC-32 is checked against the gzip trailer, as is the |
| 505 | uncompressed length, modulo 2^32. |
| 506 | |
| 507 | inflate() returns Z_OK if some progress has been made (more input processed |
| 508 | or more output produced), Z_STREAM_END if the end of the compressed data has |
| 509 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
| 510 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
| 511 | corrupted (input stream not conforming to the zlib format or incorrect check |
| 512 | value, in which case strm->msg points to a string with a more specific |
| 513 | error), Z_STREAM_ERROR if the stream structure was inconsistent (for example |
| 514 | next_in or next_out was Z_NULL, or the state was inadvertently written over |
| 515 | by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR |
| 516 | if no progress was possible or if there was not enough room in the output |
| 517 | buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
| 518 | inflate() can be called again with more input and more output space to |
| 519 | continue decompressing. If Z_DATA_ERROR is returned, the application may |
| 520 | then call inflateSync() to look for a good compression block if a partial |
| 521 | recovery of the data is to be attempted. |
| 522 | */ |
| 523 | |
| 524 | |
| 525 | ZEXTERN int ZEXPORT inflateEnd(z_streamp strm); |
| 526 | /* |
| 527 | All dynamically allocated data structures for this stream are freed. |
| 528 | This function discards any unprocessed input and does not flush any pending |
| 529 | output. |
| 530 | |
| 531 | inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state |
| 532 | was inconsistent. |
| 533 | */ |
| 534 | |
| 535 | |
| 536 | /* Advanced functions */ |
| 537 | |
| 538 | /* |
| 539 | The following functions are needed only in some special applications. |
| 540 | */ |
| 541 | |
| 542 | /* |
| 543 | ZEXTERN int ZEXPORT deflateInit2(z_streamp strm, |
| 544 | int level, |
| 545 | int method, |
| 546 | int windowBits, |
| 547 | int memLevel, |
| 548 | int strategy); |
| 549 | |
| 550 | This is another version of deflateInit with more compression options. The |
| 551 | fields zalloc, zfree and opaque must be initialized before by the caller. |
| 552 | |
| 553 | The method parameter is the compression method. It must be Z_DEFLATED in |
| 554 | this version of the library. |
| 555 | |
| 556 | The windowBits parameter is the base two logarithm of the window size |
| 557 | (the size of the history buffer). It should be in the range 8..15 for this |
| 558 | version of the library. Larger values of this parameter result in better |
| 559 | compression at the expense of memory usage. The default value is 15 if |
| 560 | deflateInit is used instead. |
| 561 | |
| 562 | For the current implementation of deflate(), a windowBits value of 8 (a |
| 563 | window size of 256 bytes) is not supported. As a result, a request for 8 |
| 564 | will result in 9 (a 512-byte window). In that case, providing 8 to |
| 565 | inflateInit2() will result in an error when the zlib header with 9 is |
| 566 | checked against the initialization of inflate(). The remedy is to not use 8 |
| 567 | with deflateInit2() with this initialization, or at least in that case use 9 |
| 568 | with inflateInit2(). |
| 569 | |
| 570 | windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
| 571 | determines the window size. deflate() will then generate raw deflate data |
| 572 | with no zlib header or trailer, and will not compute a check value. |
| 573 | |
| 574 | windowBits can also be greater than 15 for optional gzip encoding. Add |
| 575 | 16 to windowBits to write a simple gzip header and trailer around the |
| 576 | compressed data instead of a zlib wrapper. The gzip header will have no |
| 577 | file name, no extra data, no comment, no modification time (set to zero), no |
| 578 | header crc, and the operating system will be set to the appropriate value, |
| 579 | if the operating system was determined at compile time. If a gzip stream is |
| 580 | being written, strm->adler is a CRC-32 instead of an Adler-32. |
| 581 | |
| 582 | For raw deflate or gzip encoding, a request for a 256-byte window is |
| 583 | rejected as invalid, since only the zlib header provides a means of |
| 584 | transmitting the window size to the decompressor. |
| 585 | |
| 586 | The memLevel parameter specifies how much memory should be allocated |
| 587 | for the internal compression state. memLevel=1 uses minimum memory but is |
| 588 | slow and reduces compression ratio; memLevel=9 uses maximum memory for |
| 589 | optimal speed. The default value is 8. See zconf.h for total memory usage |
| 590 | as a function of windowBits and memLevel. |
| 591 | |
| 592 | The strategy parameter is used to tune the compression algorithm. Use the |
| 593 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
| 594 | filter (or predictor), Z_RLE to limit match distances to one (run-length |
| 595 | encoding), or Z_HUFFMAN_ONLY to force Huffman encoding only (no string |
| 596 | matching). Filtered data consists mostly of small values with a somewhat |
| 597 | random distribution, as produced by the PNG filters. In this case, the |
| 598 | compression algorithm is tuned to compress them better. The effect of |
| 599 | Z_FILTERED is to force more Huffman coding and less string matching than the |
| 600 | default; it is intermediate between Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. |
| 601 | Z_RLE is almost as fast as Z_HUFFMAN_ONLY, but should give better |
| 602 | compression for PNG image data than Huffman only. The degree of string |
| 603 | matching from most to none is: Z_DEFAULT_STRATEGY, Z_FILTERED, Z_RLE, then |
| 604 | Z_HUFFMAN_ONLY. The strategy parameter affects the compression ratio but |
| 605 | never the correctness of the compressed output, even if it is not set |
| 606 | optimally for the given data. Z_FIXED uses the default string matching, but |
| 607 | prevents the use of dynamic Huffman codes, allowing for a simpler decoder |
| 608 | for special applications. |
| 609 | |
| 610 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 611 | memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid |
| 612 | method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is |
| 613 | incompatible with the version assumed by the caller (ZLIB_VERSION). msg is |
| 614 | set to null if there is no error message. deflateInit2 does not perform any |
| 615 | compression: this will be done by deflate(). |
| 616 | */ |
| 617 | |
| 618 | ZEXTERN int ZEXPORT deflateSetDictionary(z_streamp strm, |
| 619 | const Bytef *dictionary, |
| 620 | uInt dictLength); |
| 621 | /* |
| 622 | Initializes the compression dictionary from the given byte sequence |
| 623 | without producing any compressed output. When using the zlib format, this |
| 624 | function must be called immediately after deflateInit, deflateInit2 or |
| 625 | deflateReset, and before any call of deflate. When doing raw deflate, this |
| 626 | function must be called either before any call of deflate, or immediately |
| 627 | after the completion of a deflate block, i.e. after all input has been |
| 628 | consumed and all output has been delivered when using any of the flush |
| 629 | options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The |
| 630 | compressor and decompressor must use exactly the same dictionary (see |
| 631 | inflateSetDictionary). |
| 632 | |
| 633 | The dictionary should consist of strings (byte sequences) that are likely |
| 634 | to be encountered later in the data to be compressed, with the most commonly |
| 635 | used strings preferably put towards the end of the dictionary. Using a |
| 636 | dictionary is most useful when the data to be compressed is short and can be |
| 637 | predicted with good accuracy; the data can then be compressed better than |
| 638 | with the default empty dictionary. |
| 639 | |
| 640 | Depending on the size of the compression data structures selected by |
| 641 | deflateInit or deflateInit2, a part of the dictionary may in effect be |
| 642 | discarded, for example if the dictionary is larger than the window size |
| 643 | provided in deflateInit or deflateInit2. Thus the strings most likely to be |
| 644 | useful should be put at the end of the dictionary, not at the front. In |
| 645 | addition, the current implementation of deflate will use at most the window |
| 646 | size minus 262 bytes of the provided dictionary. |
| 647 | |
| 648 | Upon return of this function, strm->adler is set to the Adler-32 value |
| 649 | of the dictionary; the decompressor may later use this value to determine |
| 650 | which dictionary has been used by the compressor. (The Adler-32 value |
| 651 | applies to the whole dictionary even if only a subset of the dictionary is |
| 652 | actually used by the compressor.) If a raw deflate was requested, then the |
| 653 | Adler-32 value is not computed and strm->adler is not set. |
| 654 | |
| 655 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
| 656 | parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
| 657 | inconsistent (for example if deflate has already been called for this stream |
| 658 | or if not at a block boundary for raw deflate). deflateSetDictionary does |
| 659 | not perform any compression: this will be done by deflate(). |
| 660 | */ |
| 661 | |
| 662 | ZEXTERN int ZEXPORT deflateGetDictionary(z_streamp strm, |
| 663 | Bytef *dictionary, |
| 664 | uInt *dictLength); |
| 665 | /* |
| 666 | Returns the sliding dictionary being maintained by deflate. dictLength is |
| 667 | set to the number of bytes in the dictionary, and that many bytes are copied |
| 668 | to dictionary. dictionary must have enough space, where 32768 bytes is |
| 669 | always enough. If deflateGetDictionary() is called with dictionary equal to |
| 670 | Z_NULL, then only the dictionary length is returned, and nothing is copied. |
| 671 | Similarly, if dictLength is Z_NULL, then it is not set. |
| 672 | |
| 673 | deflateGetDictionary() may return a length less than the window size, even |
| 674 | when more than the window size in input has been provided. It may return up |
| 675 | to 258 bytes less in that case, due to how zlib's implementation of deflate |
| 676 | manages the sliding window and lookahead for matches, where matches can be |
| 677 | up to 258 bytes long. If the application needs the last window-size bytes of |
| 678 | input, then that would need to be saved by the application outside of zlib. |
| 679 | |
| 680 | deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the |
| 681 | stream state is inconsistent. |
| 682 | */ |
| 683 | |
| 684 | ZEXTERN int ZEXPORT deflateCopy(z_streamp dest, |
| 685 | z_streamp source); |
| 686 | /* |
| 687 | Sets the destination stream as a complete copy of the source stream. |
| 688 | |
| 689 | This function can be useful when several compression strategies will be |
| 690 | tried, for example when there are several ways of pre-processing the input |
| 691 | data with a filter. The streams that will be discarded should then be freed |
| 692 | by calling deflateEnd. Note that deflateCopy duplicates the internal |
| 693 | compression state which can be quite large, so this strategy is slow and can |
| 694 | consume lots of memory. |
| 695 | |
| 696 | deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
| 697 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
| 698 | (such as zalloc being Z_NULL). msg is left unchanged in both source and |
| 699 | destination. |
| 700 | */ |
| 701 | |
| 702 | ZEXTERN int ZEXPORT deflateReset(z_streamp strm); |
| 703 | /* |
| 704 | This function is equivalent to deflateEnd followed by deflateInit, but |
| 705 | does not free and reallocate the internal compression state. The stream |
| 706 | will leave the compression level and any other attributes that may have been |
| 707 | set unchanged. total_in, total_out, adler, and msg are initialized. |
| 708 | |
| 709 | deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 710 | stream state was inconsistent (such as zalloc or state being Z_NULL). |
| 711 | */ |
| 712 | |
| 713 | ZEXTERN int ZEXPORT deflateParams(z_streamp strm, |
| 714 | int level, |
| 715 | int strategy); |
| 716 | /* |
| 717 | Dynamically update the compression level and compression strategy. The |
| 718 | interpretation of level and strategy is as in deflateInit2(). This can be |
| 719 | used to switch between compression and straight copy of the input data, or |
| 720 | to switch to a different kind of input data requiring a different strategy. |
| 721 | If the compression approach (which is a function of the level) or the |
| 722 | strategy is changed, and if there have been any deflate() calls since the |
| 723 | state was initialized or reset, then the input available so far is |
| 724 | compressed with the old level and strategy using deflate(strm, Z_BLOCK). |
| 725 | There are three approaches for the compression levels 0, 1..3, and 4..9 |
| 726 | respectively. The new level and strategy will take effect at the next call |
| 727 | of deflate(). |
| 728 | |
| 729 | If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does |
| 730 | not have enough output space to complete, then the parameter change will not |
| 731 | take effect. In this case, deflateParams() can be called again with the |
| 732 | same parameters and more output space to try again. |
| 733 | |
| 734 | In order to assure a change in the parameters on the first try, the |
| 735 | deflate stream should be flushed using deflate() with Z_BLOCK or other flush |
| 736 | request until strm.avail_out is not zero, before calling deflateParams(). |
| 737 | Then no more input data should be provided before the deflateParams() call. |
| 738 | If this is done, the old level and strategy will be applied to the data |
| 739 | compressed before deflateParams(), and the new level and strategy will be |
| 740 | applied to the data compressed after deflateParams(). |
| 741 | |
| 742 | deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream |
| 743 | state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if |
| 744 | there was not enough output space to complete the compression of the |
| 745 | available input data before a change in the strategy or approach. Note that |
| 746 | in the case of a Z_BUF_ERROR, the parameters are not changed. A return |
| 747 | value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be |
| 748 | retried with more output space. |
| 749 | */ |
| 750 | |
| 751 | ZEXTERN int ZEXPORT deflateTune(z_streamp strm, |
| 752 | int good_length, |
| 753 | int max_lazy, |
| 754 | int nice_length, |
| 755 | int max_chain); |
| 756 | /* |
| 757 | Fine tune deflate's internal compression parameters. This should only be |
| 758 | used by someone who understands the algorithm used by zlib's deflate for |
| 759 | searching for the best matching string, and even then only by the most |
| 760 | fanatic optimizer trying to squeeze out the last compressed bit for their |
| 761 | specific input data. Read the deflate.c source code for the meaning of the |
| 762 | max_lazy, good_length, nice_length, and max_chain parameters. |
| 763 | |
| 764 | deflateTune() can be called after deflateInit() or deflateInit2(), and |
| 765 | returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. |
| 766 | */ |
| 767 | |
| 768 | ZEXTERN uLong ZEXPORT deflateBound(z_streamp strm, uLong sourceLen); |
| 769 | ZEXTERN z_size_t ZEXPORT deflateBound_z(z_streamp strm, z_size_t sourceLen); |
| 770 | /* |
| 771 | deflateBound() returns an upper bound on the compressed size after |
| 772 | deflation of sourceLen bytes. It must be called after deflateInit() or |
| 773 | deflateInit2(), and after deflateSetHeader(), if used. This would be used |
| 774 | to allocate an output buffer for deflation in a single pass, and so would be |
| 775 | called before deflate(). If that first deflate() call is provided the |
| 776 | sourceLen input bytes, an output buffer allocated to the size returned by |
| 777 | deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed |
| 778 | to return Z_STREAM_END. Note that it is possible for the compressed size to |
| 779 | be larger than the value returned by deflateBound() if flush options other |
| 780 | than Z_FINISH or Z_NO_FLUSH are used. |
| 781 | |
| 782 | delfateBound_z() is the same, but takes and returns a size_t length. Note |
| 783 | that a long is 32 bits on Windows. |
| 784 | */ |
| 785 | |
| 786 | ZEXTERN int ZEXPORT deflatePending(z_streamp strm, |
| 787 | unsigned *pending, |
| 788 | int *bits); |
| 789 | /* |
| 790 | deflatePending() returns the number of bytes and bits of output that have |
| 791 | been generated, but not yet provided in the available output. The bytes not |
| 792 | provided would be due to the available output space having being consumed. |
| 793 | The number of bits of output not provided are between 0 and 7, where they |
| 794 | await more bits to join them in order to fill out a full byte. If pending |
| 795 | or bits are Z_NULL, then those values are not set. |
| 796 | |
| 797 | deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 798 | stream state was inconsistent. If an int is 16 bits and memLevel is 9, then |
| 799 | it is possible for the number of pending bytes to not fit in an unsigned. In |
| 800 | that case Z_BUF_ERROR is returned and *pending is set to the maximum value |
| 801 | of an unsigned. |
| 802 | */ |
| 803 | |
| 804 | ZEXTERN int ZEXPORT deflateUsed(z_streamp strm, |
| 805 | int *bits); |
| 806 | /* |
| 807 | deflateUsed() returns in *bits the most recent number of deflate bits used |
| 808 | in the last byte when flushing to a byte boundary. The result is in 1..8, or |
| 809 | 0 if there has not yet been a flush. This helps determine the location of |
| 810 | the last bit of a deflate stream. |
| 811 | |
| 812 | deflateUsed returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 813 | stream state was inconsistent. |
| 814 | */ |
| 815 | |
| 816 | ZEXTERN int ZEXPORT deflatePrime(z_streamp strm, |
| 817 | int bits, |
| 818 | int value); |
| 819 | /* |
| 820 | deflatePrime() inserts bits in the deflate output stream. The intent |
| 821 | is that this function is used to start off the deflate output with the bits |
| 822 | leftover from a previous deflate stream when appending to it. As such, this |
| 823 | function can only be used for raw deflate, and must be used before the first |
| 824 | deflate() call after a deflateInit2() or deflateReset(). bits must be less |
| 825 | than or equal to 16, and that many of the least significant bits of value |
| 826 | will be inserted in the output. |
| 827 | |
| 828 | deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough |
| 829 | room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the |
| 830 | source stream state was inconsistent. |
| 831 | */ |
| 832 | |
| 833 | ZEXTERN int ZEXPORT deflateSetHeader(z_streamp strm, |
| 834 | gz_headerp head); |
| 835 | /* |
| 836 | deflateSetHeader() provides gzip header information for when a gzip |
| 837 | stream is requested by deflateInit2(). deflateSetHeader() may be called |
| 838 | after deflateInit2() or deflateReset() and before the first call of |
| 839 | deflate(). The text, time, os, extra field, name, and comment information |
| 840 | in the provided gz_header structure are written to the gzip header (xflag is |
| 841 | ignored -- the extra flags are set according to the compression level). The |
| 842 | caller must assure that, if not Z_NULL, name and comment are terminated with |
| 843 | a zero byte, and that if extra is not Z_NULL, that extra_len bytes are |
| 844 | available there. If hcrc is true, a gzip header crc is included. Note that |
| 845 | the current versions of the command-line version of gzip (up through version |
| 846 | 1.3.x) do not support header crc's, and will report that it is a "multi-part |
| 847 | gzip file" and give up. |
| 848 | |
| 849 | If deflateSetHeader is not used, the default gzip header has text false, |
| 850 | the time set to zero, and os set to the current operating system, with no |
| 851 | extra, name, or comment fields. The gzip header is returned to the default |
| 852 | state by deflateReset(). |
| 853 | |
| 854 | deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 855 | stream state was inconsistent. |
| 856 | */ |
| 857 | |
| 858 | /* |
| 859 | ZEXTERN int ZEXPORT inflateInit2(z_streamp strm, |
| 860 | int windowBits); |
| 861 | |
| 862 | This is another version of inflateInit with an extra parameter. The |
| 863 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
| 864 | before by the caller. |
| 865 | |
| 866 | The windowBits parameter is the base two logarithm of the maximum window |
| 867 | size (the size of the history buffer). It should be in the range 8..15 for |
| 868 | this version of the library. The default value is 15 if inflateInit is used |
| 869 | instead. windowBits must be greater than or equal to the windowBits value |
| 870 | provided to deflateInit2() while compressing, or it must be equal to 15 if |
| 871 | deflateInit2() was not used. If a compressed stream with a larger window |
| 872 | size is given as input, inflate() will return with the error code |
| 873 | Z_DATA_ERROR instead of trying to allocate a larger window. |
| 874 | |
| 875 | windowBits can also be zero to request that inflate use the window size in |
| 876 | the zlib header of the compressed stream. |
| 877 | |
| 878 | windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
| 879 | determines the window size. inflate() will then process raw deflate data, |
| 880 | not looking for a zlib or gzip header, not generating a check value, and not |
| 881 | looking for any check values for comparison at the end of the stream. This |
| 882 | is for use with other formats that use the deflate compressed data format |
| 883 | such as zip. Those formats provide their own check values. If a custom |
| 884 | format is developed using the raw deflate format for compressed data, it is |
| 885 | recommended that a check value such as an Adler-32 or a CRC-32 be applied to |
| 886 | the uncompressed data as is done in the zlib, gzip, and zip formats. For |
| 887 | most applications, the zlib format should be used as is. Note that comments |
| 888 | above on the use in deflateInit2() applies to the magnitude of windowBits. |
| 889 | |
| 890 | windowBits can also be greater than 15 for optional gzip decoding. Add |
| 891 | 32 to windowBits to enable zlib and gzip decoding with automatic header |
| 892 | detection, or add 16 to decode only the gzip format (the zlib format will |
| 893 | return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a |
| 894 | CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see |
| 895 | below), inflate() will *not* automatically decode concatenated gzip members. |
| 896 | inflate() will return Z_STREAM_END at the end of the gzip member. The state |
| 897 | would need to be reset to continue decoding a subsequent gzip member. This |
| 898 | *must* be done if there is more data after a gzip member, in order for the |
| 899 | decompression to be compliant with the gzip standard (RFC 1952). |
| 900 | |
| 901 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 902 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
| 903 | version assumed by the caller, or Z_STREAM_ERROR if the parameters are |
| 904 | invalid, such as a null pointer to the structure. msg is set to null if |
| 905 | there is no error message. inflateInit2 does not perform any decompression |
| 906 | apart from possibly reading the zlib header if present: actual decompression |
| 907 | will be done by inflate(). (So next_in and avail_in may be modified, but |
| 908 | next_out and avail_out are unused and unchanged.) The current implementation |
| 909 | of inflateInit2() does not process any header information -- that is |
| 910 | deferred until inflate() is called. |
| 911 | */ |
| 912 | |
| 913 | ZEXTERN int ZEXPORT inflateSetDictionary(z_streamp strm, |
| 914 | const Bytef *dictionary, |
| 915 | uInt dictLength); |
| 916 | /* |
| 917 | Initializes the decompression dictionary from the given uncompressed byte |
| 918 | sequence. This function must be called immediately after a call of inflate, |
| 919 | if that call returned Z_NEED_DICT. The dictionary chosen by the compressor |
| 920 | can be determined from the Adler-32 value returned by that call of inflate. |
| 921 | The compressor and decompressor must use exactly the same dictionary (see |
| 922 | deflateSetDictionary). For raw inflate, this function can be called at any |
| 923 | time to set the dictionary. If the provided dictionary is smaller than the |
| 924 | window and there is already data in the window, then the provided dictionary |
| 925 | will amend what's there. The application must insure that the dictionary |
| 926 | that was used for compression is provided. |
| 927 | |
| 928 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
| 929 | parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
| 930 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
| 931 | expected one (incorrect Adler-32 value). inflateSetDictionary does not |
| 932 | perform any decompression: this will be done by subsequent calls of |
| 933 | inflate(). |
| 934 | */ |
| 935 | |
| 936 | ZEXTERN int ZEXPORT inflateGetDictionary(z_streamp strm, |
| 937 | Bytef *dictionary, |
| 938 | uInt *dictLength); |
| 939 | /* |
| 940 | Returns the sliding dictionary being maintained by inflate. dictLength is |
| 941 | set to the number of bytes in the dictionary, and that many bytes are copied |
| 942 | to dictionary. dictionary must have enough space, where 32768 bytes is |
| 943 | always enough. If inflateGetDictionary() is called with dictionary equal to |
| 944 | Z_NULL, then only the dictionary length is returned, and nothing is copied. |
| 945 | Similarly, if dictLength is Z_NULL, then it is not set. |
| 946 | |
| 947 | inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the |
| 948 | stream state is inconsistent. |
| 949 | */ |
| 950 | |
| 951 | ZEXTERN int ZEXPORT inflateSync(z_streamp strm); |
| 952 | /* |
| 953 | Skips invalid compressed data until a possible full flush point (see above |
| 954 | for the description of deflate with Z_FULL_FLUSH) can be found, or until all |
| 955 | available input is skipped. No output is provided. |
| 956 | |
| 957 | inflateSync searches for a 00 00 FF FF pattern in the compressed data. |
| 958 | All full flush points have this pattern, but not all occurrences of this |
| 959 | pattern are full flush points. |
| 960 | |
| 961 | inflateSync returns Z_OK if a possible full flush point has been found, |
| 962 | Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point |
| 963 | has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. |
| 964 | In the success case, the application may save the current value of total_in |
| 965 | which indicates where valid compressed data was found. In the error case, |
| 966 | the application may repeatedly call inflateSync, providing more input each |
| 967 | time, until success or end of the input data. |
| 968 | */ |
| 969 | |
| 970 | ZEXTERN int ZEXPORT inflateCopy(z_streamp dest, |
| 971 | z_streamp source); |
| 972 | /* |
| 973 | Sets the destination stream as a complete copy of the source stream. |
| 974 | |
| 975 | This function can be useful when randomly accessing a large stream. The |
| 976 | first pass through the stream can periodically record the inflate state, |
| 977 | allowing restarting inflate at those points when randomly accessing the |
| 978 | stream. |
| 979 | |
| 980 | inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
| 981 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
| 982 | (such as zalloc being Z_NULL). msg is left unchanged in both source and |
| 983 | destination. |
| 984 | */ |
| 985 | |
| 986 | ZEXTERN int ZEXPORT inflateReset(z_streamp strm); |
| 987 | /* |
| 988 | This function is equivalent to inflateEnd followed by inflateInit, |
| 989 | but does not free and reallocate the internal decompression state. The |
| 990 | stream will keep attributes that may have been set by inflateInit2. |
| 991 | total_in, total_out, adler, and msg are initialized. |
| 992 | |
| 993 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 994 | stream state was inconsistent (such as zalloc or state being Z_NULL). |
| 995 | */ |
| 996 | |
| 997 | ZEXTERN int ZEXPORT inflateReset2(z_streamp strm, |
| 998 | int windowBits); |
| 999 | /* |
| 1000 | This function is the same as inflateReset, but it also permits changing |
| 1001 | the wrap and window size requests. The windowBits parameter is interpreted |
| 1002 | the same as it is for inflateInit2. If the window size is changed, then the |
| 1003 | memory allocated for the window is freed, and the window will be reallocated |
| 1004 | by inflate() if needed. |
| 1005 | |
| 1006 | inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 1007 | stream state was inconsistent (such as zalloc or state being Z_NULL), or if |
| 1008 | the windowBits parameter is invalid. |
| 1009 | */ |
| 1010 | |
| 1011 | ZEXTERN int ZEXPORT inflatePrime(z_streamp strm, |
| 1012 | int bits, |
| 1013 | int value); |
| 1014 | /* |
| 1015 | This function inserts bits in the inflate input stream. The intent is to |
| 1016 | use inflatePrime() to start inflating at a bit position in the middle of a |
| 1017 | byte. The provided bits will be used before any bytes are used from |
| 1018 | next_in. This function should be used with raw inflate, before the first |
| 1019 | inflate() call, after inflateInit2() or inflateReset(). It can also be used |
| 1020 | after an inflate() return indicates the end of a deflate block or header |
| 1021 | when using Z_BLOCK. bits must be less than or equal to 16, and that many of |
| 1022 | the least significant bits of value will be inserted in the input. The |
| 1023 | other bits in value can be non-zero, and will be ignored. |
| 1024 | |
| 1025 | If bits is negative, then the input stream bit buffer is emptied. Then |
| 1026 | inflatePrime() can be called again to put bits in the buffer. This is used |
| 1027 | to clear out bits leftover after feeding inflate a block description prior |
| 1028 | to feeding inflate codes. |
| 1029 | |
| 1030 | inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 1031 | stream state was inconsistent, or if bits is out of range. If inflate was |
| 1032 | in the middle of processing a header, trailer, or stored block lengths, then |
| 1033 | it is possible for there to be only eight bits available in the bit buffer. |
| 1034 | In that case, bits > 8 is considered out of range. However, when used as |
| 1035 | outlined above, there will always be 16 bits available in the buffer for |
| 1036 | insertion. As noted in its documentation above, inflate records the number |
| 1037 | of bits in the bit buffer on return in data_type. 32 minus that is the |
| 1038 | number of bits available for insertion. inflatePrime does not update |
| 1039 | data_type with the new number of bits in buffer. |
| 1040 | */ |
| 1041 | |
| 1042 | ZEXTERN long ZEXPORT inflateMark(z_streamp strm); |
| 1043 | /* |
| 1044 | This function returns two values, one in the lower 16 bits of the return |
| 1045 | value, and the other in the remaining upper bits, obtained by shifting the |
| 1046 | return value down 16 bits. If the upper value is -1 and the lower value is |
| 1047 | zero, then inflate() is currently decoding information outside of a block. |
| 1048 | If the upper value is -1 and the lower value is non-zero, then inflate is in |
| 1049 | the middle of a stored block, with the lower value equaling the number of |
| 1050 | bytes from the input remaining to copy. If the upper value is not -1, then |
| 1051 | it is the number of bits back from the current bit position in the input of |
| 1052 | the code (literal or length/distance pair) currently being processed. In |
| 1053 | that case the lower value is the number of bytes already emitted for that |
| 1054 | code. |
| 1055 | |
| 1056 | A code is being processed if inflate is waiting for more input to complete |
| 1057 | decoding of the code, or if it has completed decoding but is waiting for |
| 1058 | more output space to write the literal or match data. |
| 1059 | |
| 1060 | inflateMark() is used to mark locations in the input data for random |
| 1061 | access, which may be at bit positions, and to note those cases where the |
| 1062 | output of a code may span boundaries of random access blocks. The current |
| 1063 | location in the input stream can be determined from avail_in and data_type |
| 1064 | as noted in the description for the Z_BLOCK flush parameter for inflate. |
| 1065 | |
| 1066 | inflateMark returns the value noted above, or -65536 if the provided |
| 1067 | source stream state was inconsistent. |
| 1068 | */ |
| 1069 | |
| 1070 | ZEXTERN int ZEXPORT inflateGetHeader(z_streamp strm, |
| 1071 | gz_headerp head); |
| 1072 | /* |
| 1073 | inflateGetHeader() requests that gzip header information be stored in the |
| 1074 | provided gz_header structure. inflateGetHeader() may be called after |
| 1075 | inflateInit2() or inflateReset(), and before the first call of inflate(). |
| 1076 | As inflate() processes the gzip stream, head->done is zero until the header |
| 1077 | is completed, at which time head->done is set to one. If a zlib stream is |
| 1078 | being decoded, then head->done is set to -1 to indicate that there will be |
| 1079 | no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be |
| 1080 | used to force inflate() to return immediately after header processing is |
| 1081 | complete and before any actual data is decompressed. |
| 1082 | |
| 1083 | The text, time, xflags, and os fields are filled in with the gzip header |
| 1084 | contents. hcrc is set to true if there is a header CRC. (The header CRC |
| 1085 | was valid if done is set to one.) The extra, name, and comment pointers |
| 1086 | much each be either Z_NULL or point to space to store that information from |
| 1087 | the header. If extra is not Z_NULL, then extra_max contains the maximum |
| 1088 | number of bytes that can be written to extra. Once done is true, extra_len |
| 1089 | contains the actual extra field length, and extra contains the extra field, |
| 1090 | or that field truncated if extra_max is less than extra_len. If name is not |
| 1091 | Z_NULL, then up to name_max characters, including the terminating zero, are |
| 1092 | written there. If comment is not Z_NULL, then up to comm_max characters, |
| 1093 | including the terminating zero, are written there. The application can tell |
| 1094 | that the name or comment did not fit in the provided space by the absence of |
| 1095 | a terminating zero. If any of extra, name, or comment are not present in |
| 1096 | the header, then that field's pointer is set to Z_NULL. This allows the use |
| 1097 | of deflateSetHeader() with the returned structure to duplicate the header. |
| 1098 | Note that if those fields initially pointed to allocated memory, then the |
| 1099 | application will need to save them elsewhere so that they can be eventually |
| 1100 | freed. |
| 1101 | |
| 1102 | If inflateGetHeader is not used, then the header information is simply |
| 1103 | discarded. The header is always checked for validity, including the header |
| 1104 | CRC if present. inflateReset() will reset the process to discard the header |
| 1105 | information. The application would need to call inflateGetHeader() again to |
| 1106 | retrieve the header from the next gzip stream. |
| 1107 | |
| 1108 | inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
| 1109 | stream state was inconsistent. |
| 1110 | */ |
| 1111 | |
| 1112 | /* |
| 1113 | ZEXTERN int ZEXPORT inflateBackInit(z_streamp strm, int windowBits, |
| 1114 | unsigned char FAR *window); |
| 1115 | |
| 1116 | Initialize the internal stream state for decompression using inflateBack() |
| 1117 | calls. The fields zalloc, zfree and opaque in strm must be initialized |
| 1118 | before the call. If zalloc and zfree are Z_NULL, then the default library- |
| 1119 | derived memory allocation routines are used. windowBits is the base two |
| 1120 | logarithm of the window size, in the range 8..15. window is a caller |
| 1121 | supplied buffer of that size. Except for special applications where it is |
| 1122 | assured that deflate was used with small window sizes, windowBits must be 15 |
| 1123 | and a 32K byte window must be supplied to be able to decompress general |
| 1124 | deflate streams. |
| 1125 | |
| 1126 | See inflateBack() for the usage of these routines. |
| 1127 | |
| 1128 | inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of |
| 1129 | the parameters are invalid, Z_MEM_ERROR if the internal state could not be |
| 1130 | allocated, or Z_VERSION_ERROR if the version of the library does not match |
| 1131 | the version of the header file. |
| 1132 | */ |
| 1133 | |
| 1134 | typedef unsigned (*in_func)(void FAR *, |
| 1135 | z_const unsigned char FAR * FAR *); |
| 1136 | typedef int (*out_func)(void FAR *, unsigned char FAR *, unsigned); |
| 1137 | |
| 1138 | ZEXTERN int ZEXPORT inflateBack(z_streamp strm, |
| 1139 | in_func in, void FAR *in_desc, |
| 1140 | out_func out, void FAR *out_desc); |
| 1141 | /* |
| 1142 | inflateBack() does a raw inflate with a single call using a call-back |
| 1143 | interface for input and output. This is potentially more efficient than |
| 1144 | inflate() for file i/o applications, in that it avoids copying between the |
| 1145 | output and the sliding window by simply making the window itself the output |
| 1146 | buffer. inflate() can be faster on modern CPUs when used with large |
| 1147 | buffers. inflateBack() trusts the application to not change the output |
| 1148 | buffer passed by the output function, at least until inflateBack() returns. |
| 1149 | |
| 1150 | inflateBackInit() must be called first to allocate the internal state |
| 1151 | and to initialize the state with the user-provided window buffer. |
| 1152 | inflateBack() may then be used multiple times to inflate a complete, raw |
| 1153 | deflate stream with each call. inflateBackEnd() is then called to free the |
| 1154 | allocated state. |
| 1155 | |
| 1156 | A raw deflate stream is one with no zlib or gzip header or trailer. |
| 1157 | This routine would normally be used in a utility that reads zip or gzip |
| 1158 | files and writes out uncompressed files. The utility would decode the |
| 1159 | header and process the trailer on its own, hence this routine expects only |
| 1160 | the raw deflate stream to decompress. This is different from the default |
| 1161 | behavior of inflate(), which expects a zlib header and trailer around the |
| 1162 | deflate stream. |
| 1163 | |
| 1164 | inflateBack() uses two subroutines supplied by the caller that are then |
| 1165 | called by inflateBack() for input and output. inflateBack() calls those |
| 1166 | routines until it reads a complete deflate stream and writes out all of the |
| 1167 | uncompressed data, or until it encounters an error. The function's |
| 1168 | parameters and return types are defined above in the in_func and out_func |
| 1169 | typedefs. inflateBack() will call in(in_desc, &buf) which should return the |
| 1170 | number of bytes of provided input, and a pointer to that input in buf. If |
| 1171 | there is no input available, in() must return zero -- buf is ignored in that |
| 1172 | case -- and inflateBack() will return a buffer error. inflateBack() will |
| 1173 | call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. |
| 1174 | out() should return zero on success, or non-zero on failure. If out() |
| 1175 | returns non-zero, inflateBack() will return with an error. Neither in() nor |
| 1176 | out() are permitted to change the contents of the window provided to |
| 1177 | inflateBackInit(), which is also the buffer that out() uses to write from. |
| 1178 | The length written by out() will be at most the window size. Any non-zero |
| 1179 | amount of input may be provided by in(). |
| 1180 | |
| 1181 | For convenience, inflateBack() can be provided input on the first call by |
| 1182 | setting strm->next_in and strm->avail_in. If that input is exhausted, then |
| 1183 | in() will be called. Therefore strm->next_in must be initialized before |
| 1184 | calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called |
| 1185 | immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in |
| 1186 | must also be initialized, and then if strm->avail_in is not zero, input will |
| 1187 | initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
| 1188 | |
| 1189 | The in_desc and out_desc parameters of inflateBack() is passed as the |
| 1190 | first parameter of in() and out() respectively when they are called. These |
| 1191 | descriptors can be optionally used to pass any information that the caller- |
| 1192 | supplied in() and out() functions need to do their job. |
| 1193 | |
| 1194 | On return, inflateBack() will set strm->next_in and strm->avail_in to |
| 1195 | pass back any unused input that was provided by the last in() call. The |
| 1196 | return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR |
| 1197 | if in() or out() returned an error, Z_DATA_ERROR if there was a format error |
| 1198 | in the deflate stream (in which case strm->msg is set to indicate the nature |
| 1199 | of the error), or Z_STREAM_ERROR if the stream was not properly initialized. |
| 1200 | In the case of Z_BUF_ERROR, an input or output error can be distinguished |
| 1201 | using strm->next_in which will be Z_NULL only if in() returned an error. If |
| 1202 | strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning |
| 1203 | non-zero. (in() will always be called before out(), so strm->next_in is |
| 1204 | assured to be defined if out() returns non-zero.) Note that inflateBack() |
| 1205 | cannot return Z_OK. |
| 1206 | */ |
| 1207 | |
| 1208 | ZEXTERN int ZEXPORT inflateBackEnd(z_streamp strm); |
| 1209 | /* |
| 1210 | All memory allocated by inflateBackInit() is freed. |
| 1211 | |
| 1212 | inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream |
| 1213 | state was inconsistent. |
| 1214 | */ |
| 1215 | |
| 1216 | ZEXTERN uLong ZEXPORT zlibCompileFlags(void); |
| 1217 | /* Return flags indicating compile-time options. |
| 1218 | |
| 1219 | Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: |
| 1220 | 1.0: size of uInt |
| 1221 | 3.2: size of uLong |
| 1222 | 5.4: size of voidpf (pointer) |
| 1223 | 7.6: size of z_off_t |
| 1224 | |
| 1225 | Compiler, assembler, and debug options: |
| 1226 | 8: ZLIB_DEBUG |
| 1227 | 9: ASMV or ASMINF -- use ASM code |
| 1228 | 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention |
| 1229 | 11: 0 (reserved) |
| 1230 | |
| 1231 | One-time table building (smaller code, but not thread-safe if true): |
| 1232 | 12: BUILDFIXED -- build static block decoding tables when needed |
| 1233 | 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed |
| 1234 | 14,15: 0 (reserved) |
| 1235 | |
| 1236 | Library content (indicates missing functionality): |
| 1237 | 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking |
| 1238 | deflate code when not needed) |
| 1239 | 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect |
| 1240 | and decode gzip streams (to avoid linking crc code) |
| 1241 | 18-19: 0 (reserved) |
| 1242 | |
| 1243 | Operation variations (changes in library functionality): |
| 1244 | 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate |
| 1245 | 21: FASTEST -- deflate algorithm with only one, lowest compression level |
| 1246 | 22,23: 0 (reserved) |
| 1247 | |
| 1248 | The sprintf variant used by gzprintf (all zeros is best): |
| 1249 | 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format |
| 1250 | 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() is not secure! |
| 1251 | 26: 0 = returns value, 1 = void -- 1 means inferred string length returned |
| 1252 | 27: 0 = gzprintf() present, 1 = not -- 1 means gzprintf() returns an error |
| 1253 | |
| 1254 | Remainder: |
| 1255 | 28-31: 0 (reserved) |
| 1256 | */ |
| 1257 | |
| 1258 | #ifndef Z_SOLO |
| 1259 | |
| 1260 | /* utility functions */ |
| 1261 | |
| 1262 | /* |
| 1263 | The following utility functions are implemented on top of the basic |
| 1264 | stream-oriented functions. To simplify the interface, some default options |
| 1265 | are assumed (compression level and memory usage, standard memory allocation |
| 1266 | functions). The source code of these utility functions can be modified if |
| 1267 | you need special options. The _z versions of the functions use the size_t |
| 1268 | type for lengths. Note that a long is 32 bits on Windows. |
| 1269 | */ |
| 1270 | |
| 1271 | ZEXTERN int ZEXPORT compress(Bytef *dest, uLongf *destLen, |
| 1272 | const Bytef *source, uLong sourceLen); |
| 1273 | ZEXTERN int ZEXPORT compress_z(Bytef *dest, z_size_t *destLen, |
| 1274 | const Bytef *source, z_size_t sourceLen); |
| 1275 | /* |
| 1276 | Compresses the source buffer into the destination buffer. sourceLen is |
| 1277 | the byte length of the source buffer. Upon entry, destLen is the total size |
| 1278 | of the destination buffer, which must be at least the value returned by |
| 1279 | compressBound(sourceLen). Upon exit, destLen is the actual size of the |
| 1280 | compressed data. compress() is equivalent to compress2() with a level |
| 1281 | parameter of Z_DEFAULT_COMPRESSION. |
| 1282 | |
| 1283 | compress returns Z_OK if success, Z_MEM_ERROR if there was not |
| 1284 | enough memory, Z_BUF_ERROR if there was not enough room in the output |
| 1285 | buffer. |
| 1286 | */ |
| 1287 | |
| 1288 | ZEXTERN int ZEXPORT compress2(Bytef *dest, uLongf *destLen, |
| 1289 | const Bytef *source, uLong sourceLen, |
| 1290 | int level); |
| 1291 | ZEXTERN int ZEXPORT compress2_z(Bytef *dest, z_size_t *destLen, |
| 1292 | const Bytef *source, z_size_t sourceLen, |
| 1293 | int level); |
| 1294 | /* |
| 1295 | Compresses the source buffer into the destination buffer. The level |
| 1296 | parameter has the same meaning as in deflateInit. sourceLen is the byte |
| 1297 | length of the source buffer. Upon entry, destLen is the total size of the |
| 1298 | destination buffer, which must be at least the value returned by |
| 1299 | compressBound(sourceLen). Upon exit, destLen is the actual size of the |
| 1300 | compressed data. |
| 1301 | |
| 1302 | compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
| 1303 | memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
| 1304 | Z_STREAM_ERROR if the level parameter is invalid. |
| 1305 | */ |
| 1306 | |
| 1307 | ZEXTERN uLong ZEXPORT compressBound(uLong sourceLen); |
| 1308 | ZEXTERN z_size_t ZEXPORT compressBound_z(z_size_t sourceLen); |
| 1309 | /* |
| 1310 | compressBound() returns an upper bound on the compressed size after |
| 1311 | compress() or compress2() on sourceLen bytes. It would be used before a |
| 1312 | compress() or compress2() call to allocate the destination buffer. |
| 1313 | */ |
| 1314 | |
| 1315 | ZEXTERN int ZEXPORT uncompress(Bytef *dest, uLongf *destLen, |
| 1316 | const Bytef *source, uLong sourceLen); |
| 1317 | ZEXTERN int ZEXPORT uncompress_z(Bytef *dest, z_size_t *destLen, |
| 1318 | const Bytef *source, z_size_t sourceLen); |
| 1319 | /* |
| 1320 | Decompresses the source buffer into the destination buffer. sourceLen is |
| 1321 | the byte length of the source buffer. On entry, *destLen is the total size |
| 1322 | of the destination buffer, which must be large enough to hold the entire |
| 1323 | uncompressed data. (The size of the uncompressed data must have been saved |
| 1324 | previously by the compressor and transmitted to the decompressor by some |
| 1325 | mechanism outside the scope of this compression library.) On exit, *destLen |
| 1326 | is the actual size of the uncompressed data. |
| 1327 | |
| 1328 | uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
| 1329 | enough memory, Z_BUF_ERROR if there was not enough room in the output |
| 1330 | buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In |
| 1331 | the case where there is not enough room, uncompress() will fill the output |
| 1332 | buffer with the uncompressed data up to that point. |
| 1333 | */ |
| 1334 | |
| 1335 | ZEXTERN int ZEXPORT uncompress2(Bytef *dest, uLongf *destLen, |
| 1336 | const Bytef *source, uLong *sourceLen); |
| 1337 | ZEXTERN int ZEXPORT uncompress2_z(Bytef *dest, z_size_t *destLen, |
| 1338 | const Bytef *source, z_size_t *sourceLen); |
| 1339 | /* |
| 1340 | Same as uncompress, except that sourceLen is a pointer, where the |
| 1341 | length of the source is *sourceLen. On return, *sourceLen is the number of |
| 1342 | source bytes consumed. |
| 1343 | */ |
| 1344 | |
| 1345 | /* gzip file access functions */ |
| 1346 | |
| 1347 | /* |
| 1348 | This library supports reading and writing files in gzip (.gz) format with |
| 1349 | an interface similar to that of stdio, using the functions that start with |
| 1350 | "gz". The gzip format is different from the zlib format. gzip is a gzip |
| 1351 | wrapper, documented in RFC 1952, wrapped around a deflate stream. |
| 1352 | */ |
| 1353 | |
| 1354 | typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ |
| 1355 | |
| 1356 | /* |
| 1357 | ZEXTERN gzFile ZEXPORT gzopen(const char *path, const char *mode); |
| 1358 | |
| 1359 | Open the gzip (.gz) file at path for reading and decompressing, or |
| 1360 | compressing and writing. The mode parameter is as in fopen ("rb" or "wb") |
| 1361 | but can also include a compression level ("wb9") or a strategy: 'f' for |
| 1362 | filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h", |
| 1363 | 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression |
| 1364 | as in "wb9F". (See the description of deflateInit2 for more information |
| 1365 | about the strategy parameter.) 'T' will request transparent writing or |
| 1366 | appending with no compression and not using the gzip format. 'T' cannot be |
| 1367 | used to force transparent reading. Transparent reading is automatically |
| 1368 | performed if there is no gzip header at the start. Transparent reading can |
| 1369 | be disabled with the 'G' option, which will instead return an error if there |
| 1370 | is no gzip header. 'N' will open the file in non-blocking mode. |
| 1371 | |
| 1372 | 'a' can be used instead of 'w' to request that the gzip stream that will |
| 1373 | be written be appended to the file. '+' will result in an error, since |
| 1374 | reading and writing to the same gzip file is not supported. The addition of |
| 1375 | 'x' when writing will create the file exclusively, which fails if the file |
| 1376 | already exists. On systems that support it, the addition of 'e' when |
| 1377 | reading or writing will set the flag to close the file on an execve() call. |
| 1378 | |
| 1379 | These functions, as well as gzip, will read and decode a sequence of gzip |
| 1380 | streams in a file. The append function of gzopen() can be used to create |
| 1381 | such a file. (Also see gzflush() for another way to do this.) When |
| 1382 | appending, gzopen does not test whether the file begins with a gzip stream, |
| 1383 | nor does it look for the end of the gzip streams to begin appending. gzopen |
| 1384 | will simply append a gzip stream to the existing file. |
| 1385 | |
| 1386 | gzopen can be used to read a file which is not in gzip format; in this |
| 1387 | case gzread will directly read from the file without decompression. When |
| 1388 | reading, this will be detected automatically by looking for the magic two- |
| 1389 | byte gzip header. |
| 1390 | |
| 1391 | gzopen returns NULL if the file could not be opened, if there was |
| 1392 | insufficient memory to allocate the gzFile state, or if an invalid mode was |
| 1393 | specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). |
| 1394 | errno can be checked to determine if the reason gzopen failed was that the |
| 1395 | file could not be opened. Note that if 'N' is in mode for non-blocking, the |
| 1396 | open() itself can fail in order to not block. In that case gzopen() will |
| 1397 | return NULL and errno will be EAGAIN or ENONBLOCK. The call to gzopen() can |
| 1398 | then be re-tried. If the application would like to block on opening the |
| 1399 | file, then it can use open() without O_NONBLOCK, and then gzdopen() with the |
| 1400 | resulting file descriptor and 'N' in the mode, which will set it to non- |
| 1401 | blocking. |
| 1402 | */ |
| 1403 | |
| 1404 | ZEXTERN gzFile ZEXPORT gzdopen(int fd, const char *mode); |
| 1405 | /* |
| 1406 | Associate a gzFile with the file descriptor fd. File descriptors are |
| 1407 | obtained from calls like open, dup, creat, pipe or fileno (if the file has |
| 1408 | been previously opened with fopen). The mode parameter is as in gzopen. An |
| 1409 | 'e' in mode will set fd's flag to close the file on an execve() call. An 'N' |
| 1410 | in mode will set fd's non-blocking flag. |
| 1411 | |
| 1412 | The next call of gzclose on the returned gzFile will also close the file |
| 1413 | descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor |
| 1414 | fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, |
| 1415 | mode);. The duplicated descriptor should be saved to avoid a leak, since |
| 1416 | gzdopen does not close fd if it fails. If you are using fileno() to get the |
| 1417 | file descriptor from a FILE *, then you will have to use dup() to avoid |
| 1418 | double-close()ing the file descriptor. Both gzclose() and fclose() will |
| 1419 | close the associated file descriptor, so they need to have different file |
| 1420 | descriptors. |
| 1421 | |
| 1422 | gzdopen returns NULL if there was insufficient memory to allocate the |
| 1423 | gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not |
| 1424 | provided, or '+' was provided), or if fd is -1. The file descriptor is not |
| 1425 | used until the next gz* read, write, seek, or close operation, so gzdopen |
| 1426 | will not detect if fd is invalid (unless fd is -1). |
| 1427 | */ |
| 1428 | |
| 1429 | ZEXTERN int ZEXPORT gzbuffer(gzFile file, unsigned size); |
| 1430 | /* |
| 1431 | Set the internal buffer size used by this library's functions for file to |
| 1432 | size. The default buffer size is 8192 bytes. This function must be called |
| 1433 | after gzopen() or gzdopen(), and before any other calls that read or write |
| 1434 | the file. The buffer memory allocation is always deferred to the first read |
| 1435 | or write. Three times that size in buffer space is allocated. A larger |
| 1436 | buffer size of, for example, 64K or 128K bytes will noticeably increase the |
| 1437 | speed of decompression (reading). |
| 1438 | |
| 1439 | The new buffer size also affects the maximum length for gzprintf(). |
| 1440 | |
| 1441 | gzbuffer() returns 0 on success, or -1 on failure, such as being called |
| 1442 | too late. |
| 1443 | */ |
| 1444 | |
| 1445 | ZEXTERN int ZEXPORT gzsetparams(gzFile file, int level, int strategy); |
| 1446 | /* |
| 1447 | Dynamically update the compression level and strategy for file. See the |
| 1448 | description of deflateInit2 for the meaning of these parameters. Previously |
| 1449 | provided data is flushed before applying the parameter changes. |
| 1450 | |
| 1451 | gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not |
| 1452 | opened for writing, Z_ERRNO if there is an error writing the flushed data, |
| 1453 | or Z_MEM_ERROR if there is a memory allocation error. |
| 1454 | */ |
| 1455 | |
| 1456 | ZEXTERN int ZEXPORT gzread(gzFile file, voidp buf, unsigned len); |
| 1457 | /* |
| 1458 | Read and decompress up to len uncompressed bytes from file into buf. If |
| 1459 | the input file is not in gzip format, gzread copies the given number of |
| 1460 | bytes into the buffer directly from the file. |
| 1461 | |
| 1462 | After reaching the end of a gzip stream in the input, gzread will continue |
| 1463 | to read, looking for another gzip stream. Any number of gzip streams may be |
| 1464 | concatenated in the input file, and will all be decompressed by gzread(). |
| 1465 | If something other than a gzip stream is encountered after a gzip stream, |
| 1466 | that remaining trailing garbage is ignored (and no error is returned). |
| 1467 | |
| 1468 | gzread can be used to read a gzip file that is being concurrently written. |
| 1469 | Upon reaching the end of the input, gzread will return with the available |
| 1470 | data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then |
| 1471 | gzclearerr can be used to clear the end of file indicator in order to permit |
| 1472 | gzread to be tried again. Z_OK indicates that a gzip stream was completed |
| 1473 | on the last gzread. Z_BUF_ERROR indicates that the input file ended in the |
| 1474 | middle of a gzip stream. Note that gzread does not return -1 in the event |
| 1475 | of an incomplete gzip stream. This error is deferred until gzclose(), which |
| 1476 | will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip |
| 1477 | stream. Alternatively, gzerror can be used before gzclose to detect this |
| 1478 | case. |
| 1479 | |
| 1480 | gzread can be used to read a gzip file on a non-blocking device. If the |
| 1481 | input stalls and there is no uncompressed data to return, then gzread() will |
| 1482 | return -1, and errno will be EAGAIN or EWOULDBLOCK. gzread() can then be |
| 1483 | called again. |
| 1484 | |
| 1485 | gzread returns the number of uncompressed bytes actually read, less than |
| 1486 | len for end of file, or -1 for error. If len is too large to fit in an int, |
| 1487 | then nothing is read, -1 is returned, and the error state is set to |
| 1488 | Z_STREAM_ERROR. If some data was read before an error, then that data is |
| 1489 | returned until exhausted, after which the next call will signal the error. |
| 1490 | */ |
| 1491 | |
| 1492 | ZEXTERN z_size_t ZEXPORT gzfread(voidp buf, z_size_t size, z_size_t nitems, |
| 1493 | gzFile file); |
| 1494 | /* |
| 1495 | Read and decompress up to nitems items of size size from file into buf, |
| 1496 | otherwise operating as gzread() does. This duplicates the interface of |
| 1497 | stdio's fread(), with size_t request and return types. If the library |
| 1498 | defines size_t, then z_size_t is identical to size_t. If not, then z_size_t |
| 1499 | is an unsigned integer type that can contain a pointer. |
| 1500 | |
| 1501 | gzfread() returns the number of full items read of size size, or zero if |
| 1502 | the end of the file was reached and a full item could not be read, or if |
| 1503 | there was an error. gzerror() must be consulted if zero is returned in |
| 1504 | order to determine if there was an error. If the multiplication of size and |
| 1505 | nitems overflows, i.e. the product does not fit in a z_size_t, then nothing |
| 1506 | is read, zero is returned, and the error state is set to Z_STREAM_ERROR. |
| 1507 | |
| 1508 | In the event that the end of file is reached and only a partial item is |
| 1509 | available at the end, i.e. the remaining uncompressed data length is not a |
| 1510 | multiple of size, then the final partial item is nevertheless read into buf |
| 1511 | and the end-of-file flag is set. The length of the partial item read is not |
| 1512 | provided, but could be inferred from the result of gztell(). This behavior |
| 1513 | is the same as that of fread() implementations in common libraries. This |
| 1514 | could result in data loss if used with size != 1 when reading a concurrently |
| 1515 | written file or a non-blocking file. In that case, use size == 1 or gzread() |
| 1516 | instead. |
| 1517 | */ |
| 1518 | |
| 1519 | ZEXTERN int ZEXPORT gzwrite(gzFile file, voidpc buf, unsigned len); |
| 1520 | /* |
| 1521 | Compress and write the len uncompressed bytes at buf to file. gzwrite |
| 1522 | returns the number of uncompressed bytes written, or 0 in case of error or |
| 1523 | if len is 0. If the write destination is non-blocking, then gzwrite() may |
| 1524 | return a number of bytes written that is not 0 and less than len. |
| 1525 | |
| 1526 | If len does not fit in an int, then 0 is returned and nothing is written. |
| 1527 | */ |
| 1528 | |
| 1529 | ZEXTERN z_size_t ZEXPORT gzfwrite(voidpc buf, z_size_t size, |
| 1530 | z_size_t nitems, gzFile file); |
| 1531 | /* |
| 1532 | Compress and write nitems items of size size from buf to file, duplicating |
| 1533 | the interface of stdio's fwrite(), with size_t request and return types. If |
| 1534 | the library defines size_t, then z_size_t is identical to size_t. If not, |
| 1535 | then z_size_t is an unsigned integer type that can contain a pointer. |
| 1536 | |
| 1537 | gzfwrite() returns the number of full items written of size size, or zero |
| 1538 | if there was an error. If the multiplication of size and nitems overflows, |
| 1539 | i.e. the product does not fit in a z_size_t, then nothing is written, zero |
| 1540 | is returned, and the error state is set to Z_STREAM_ERROR. |
| 1541 | |
| 1542 | If writing a concurrently read file or a non-blocking file with size != 1, |
| 1543 | a partial item could be written, with no way of knowing how much of it was |
| 1544 | not written, resulting in data loss. In that case, use size == 1 or |
| 1545 | gzwrite() instead. |
| 1546 | */ |
| 1547 | |
| 1548 | #if defined(STDC) || defined(Z_HAVE_STDARG_H) |
| 1549 | ZEXTERN int ZEXPORTVA gzprintf(gzFile file, const char *format, ...); |
| 1550 | #else |
| 1551 | ZEXTERN int ZEXPORTVA gzprintf(); |
| 1552 | #endif |
| 1553 | /* |
| 1554 | Convert, format, compress, and write the arguments (...) to file under |
| 1555 | control of the string format, as in fprintf. gzprintf returns the number of |
| 1556 | uncompressed bytes actually written, or a negative zlib error code in case |
| 1557 | of error. The number of uncompressed bytes written is limited to 8191, or |
| 1558 | one less than the buffer size given to gzbuffer(). The caller should assure |
| 1559 | that this limit is not exceeded. If it is exceeded, then gzprintf() will |
| 1560 | return an error (0) with nothing written. |
| 1561 | |
| 1562 | In that last case, there may also be a buffer overflow with unpredictable |
| 1563 | consequences, which is possible only if zlib was compiled with the insecure |
| 1564 | functions sprintf() or vsprintf(), because the secure snprintf() and |
| 1565 | vsnprintf() functions were not available. That would only be the case for |
| 1566 | a non-ANSI C compiler. zlib may have been built without gzprintf() because |
| 1567 | secure functions were not available and having gzprintf() be insecure was |
| 1568 | not an option, in which case, gzprintf() returns Z_STREAM_ERROR. All of |
| 1569 | these possibilities can be determined using zlibCompileFlags(). |
| 1570 | |
| 1571 | If a Z_BUF_ERROR is returned, then nothing was written due to a stall on |
| 1572 | the non-blocking write destination. |
| 1573 | */ |
| 1574 | |
| 1575 | ZEXTERN int ZEXPORT gzputs(gzFile file, const char *s); |
| 1576 | /* |
| 1577 | Compress and write the given null-terminated string s to file, excluding |
| 1578 | the terminating null character. |
| 1579 | |
| 1580 | gzputs returns the number of characters written, or -1 in case of error. |
| 1581 | The number of characters written may be less than the length of the string |
| 1582 | if the write destination is non-blocking. |
| 1583 | |
| 1584 | If the length of the string does not fit in an int, then -1 is returned |
| 1585 | and nothing is written. |
| 1586 | */ |
| 1587 | |
| 1588 | ZEXTERN char * ZEXPORT gzgets(gzFile file, char *buf, int len); |
| 1589 | /* |
| 1590 | Read and decompress bytes from file into buf, until len-1 characters are |
| 1591 | read, or until a newline character is read and transferred to buf, or an |
| 1592 | end-of-file condition is encountered. If any characters are read or if len |
| 1593 | is one, the string is terminated with a null character. If no characters |
| 1594 | are read due to an end-of-file or len is less than one, then the buffer is |
| 1595 | left untouched. |
| 1596 | |
| 1597 | gzgets returns buf which is a null-terminated string, or it returns NULL |
| 1598 | for end-of-file or in case of error. If some data was read before an error, |
| 1599 | then that data is returned until exhausted, after which the next call will |
| 1600 | return NULL to signal the error. |
| 1601 | |
| 1602 | gzgets can be used on a file being concurrently written, and on a non- |
| 1603 | blocking device, both as for gzread(). However lines may be broken in the |
| 1604 | middle, leaving it up to the application to reassemble them as needed. |
| 1605 | */ |
| 1606 | |
| 1607 | ZEXTERN int ZEXPORT gzputc(gzFile file, int c); |
| 1608 | /* |
| 1609 | Compress and write c, converted to an unsigned char, into file. gzputc |
| 1610 | returns the value that was written, or -1 in case of error. |
| 1611 | */ |
| 1612 | |
| 1613 | ZEXTERN int ZEXPORT gzgetc(gzFile file); |
| 1614 | /* |
| 1615 | Read and decompress one byte from file. gzgetc returns this byte or -1 in |
| 1616 | case of end of file or error. If some data was read before an error, then |
| 1617 | that data is returned until exhausted, after which the next call will return |
| 1618 | -1 to signal the error. |
| 1619 | |
| 1620 | This is implemented as a macro for speed. As such, it does not do all of |
| 1621 | the checking the other functions do. I.e. it does not check to see if file |
| 1622 | is NULL, nor whether the structure file points to has been clobbered or not. |
| 1623 | |
| 1624 | gzgetc can be used to read a gzip file on a non-blocking device. If the |
| 1625 | input stalls and there is no uncompressed data to return, then gzgetc() will |
| 1626 | return -1, and errno will be EAGAIN or EWOULDBLOCK. gzread() can then be |
| 1627 | called again. |
| 1628 | */ |
| 1629 | |
| 1630 | ZEXTERN int ZEXPORT gzungetc(int c, gzFile file); |
| 1631 | /* |
| 1632 | Push c back onto the stream for file to be read as the first character on |
| 1633 | the next read. At least one character of push-back is always allowed. |
| 1634 | gzungetc() returns the character pushed, or -1 on failure. gzungetc() will |
| 1635 | fail if c is -1, and may fail if a character has been pushed but not read |
| 1636 | yet. If gzungetc is used immediately after gzopen or gzdopen, at least the |
| 1637 | output buffer size of pushed characters is allowed. (See gzbuffer above.) |
| 1638 | The pushed character will be discarded if the stream is repositioned with |
| 1639 | gzseek() or gzrewind(). |
| 1640 | |
| 1641 | gzungetc(-1, file) will force any pending seek to execute. Then gztell() |
| 1642 | will report the position, even if the requested seek reached end of file. |
| 1643 | This can be used to determine the number of uncompressed bytes in a gzip |
| 1644 | file without having to read it into a buffer. |
| 1645 | */ |
| 1646 | |
| 1647 | ZEXTERN int ZEXPORT gzflush(gzFile file, int flush); |
| 1648 | /* |
| 1649 | Flush all pending output to file. The parameter flush is as in the |
| 1650 | deflate() function. The return value is the zlib error number (see function |
| 1651 | gzerror below). gzflush is only permitted when writing. |
| 1652 | |
| 1653 | If the flush parameter is Z_FINISH, the remaining data is written and the |
| 1654 | gzip stream is completed in the output. If gzwrite() is called again, a new |
| 1655 | gzip stream will be started in the output. gzread() is able to read such |
| 1656 | concatenated gzip streams. |
| 1657 | |
| 1658 | gzflush should be called only when strictly necessary because it will |
| 1659 | degrade compression if called too often. |
| 1660 | */ |
| 1661 | |
| 1662 | /* |
| 1663 | ZEXTERN z_off_t ZEXPORT gzseek(gzFile file, |
| 1664 | z_off_t offset, int whence); |
| 1665 | |
| 1666 | Set the starting position to offset relative to whence for the next gzread |
| 1667 | or gzwrite on file. The offset represents a number of bytes in the |
| 1668 | uncompressed data stream. The whence parameter is defined as in lseek(2); |
| 1669 | the value SEEK_END is not supported. |
| 1670 | |
| 1671 | If the file is opened for reading, this function is emulated but can be |
| 1672 | extremely slow. If the file is opened for writing, only forward seeks are |
| 1673 | supported; gzseek then compresses a sequence of zeroes up to the new |
| 1674 | starting position. For reading or writing, any actual seeking is deferred |
| 1675 | until the next read or write operation, or close operation when writing. |
| 1676 | |
| 1677 | gzseek returns the resulting offset location as measured in bytes from |
| 1678 | the beginning of the uncompressed stream, or -1 in case of error, in |
| 1679 | particular if the file is opened for writing and the new starting position |
| 1680 | would be before the current position. |
| 1681 | */ |
| 1682 | |
| 1683 | ZEXTERN int ZEXPORT gzrewind(gzFile file); |
| 1684 | /* |
| 1685 | Rewind file. This function is supported only for reading. |
| 1686 | |
| 1687 | gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET). |
| 1688 | */ |
| 1689 | |
| 1690 | /* |
| 1691 | ZEXTERN z_off_t ZEXPORT gztell(gzFile file); |
| 1692 | |
| 1693 | Return the starting position for the next gzread or gzwrite on file. |
| 1694 | This position represents a number of bytes in the uncompressed data stream, |
| 1695 | and is zero when starting, even if appending or reading a gzip stream from |
| 1696 | the middle of a file using gzdopen(). |
| 1697 | |
| 1698 | gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
| 1699 | */ |
| 1700 | |
| 1701 | /* |
| 1702 | ZEXTERN z_off_t ZEXPORT gzoffset(gzFile file); |
| 1703 | |
| 1704 | Return the current compressed (actual) read or write offset of file. This |
| 1705 | offset includes the count of bytes that precede the gzip stream, for example |
| 1706 | when appending or when using gzdopen() for reading. When reading, the |
| 1707 | offset does not include as yet unused buffered input. This information can |
| 1708 | be used for a progress indicator. On error, gzoffset() returns -1. |
| 1709 | */ |
| 1710 | |
| 1711 | ZEXTERN int ZEXPORT gzeof(gzFile file); |
| 1712 | /* |
| 1713 | Return true (1) if the end-of-file indicator for file has been set while |
| 1714 | reading, false (0) otherwise. Note that the end-of-file indicator is set |
| 1715 | only if the read tried to go past the end of the input, but came up short. |
| 1716 | Therefore, just like feof(), gzeof() may return false even if there is no |
| 1717 | more data to read, in the event that the last read request was for the exact |
| 1718 | number of bytes remaining in the input file. This will happen if the input |
| 1719 | file size is an exact multiple of the buffer size. |
| 1720 | |
| 1721 | If gzeof() returns true, then the read functions will return no more data, |
| 1722 | unless the end-of-file indicator is reset by gzclearerr() and the input file |
| 1723 | has grown since the previous end of file was detected. |
| 1724 | */ |
| 1725 | |
| 1726 | ZEXTERN int ZEXPORT gzdirect(gzFile file); |
| 1727 | /* |
| 1728 | Return true (1) if file is being copied directly while reading, or false |
| 1729 | (0) if file is a gzip stream being decompressed. |
| 1730 | |
| 1731 | If the input file is empty, gzdirect() will return true, since the input |
| 1732 | does not contain a gzip stream. |
| 1733 | |
| 1734 | If gzdirect() is used immediately after gzopen() or gzdopen() it will |
| 1735 | cause buffers to be allocated to allow reading the file to determine if it |
| 1736 | is a gzip file. Therefore if gzbuffer() is used, it should be called before |
| 1737 | gzdirect(). If the input is being written concurrently or the device is non- |
| 1738 | blocking, then gzdirect() may give a different answer once four bytes of |
| 1739 | input have been accumulated, which is what is needed to confirm or deny a |
| 1740 | gzip header. Before this, gzdirect() will return true (1). |
| 1741 | |
| 1742 | When writing, gzdirect() returns true (1) if transparent writing was |
| 1743 | requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: |
| 1744 | gzdirect() is not needed when writing. Transparent writing must be |
| 1745 | explicitly requested, so the application already knows the answer. When |
| 1746 | linking statically, using gzdirect() will include all of the zlib code for |
| 1747 | gzip file reading and decompression, which may not be desired.) |
| 1748 | */ |
| 1749 | |
| 1750 | ZEXTERN int ZEXPORT gzclose(gzFile file); |
| 1751 | /* |
| 1752 | Flush all pending output for file, if necessary, close file and |
| 1753 | deallocate the (de)compression state. Note that once file is closed, you |
| 1754 | cannot call gzerror with file, since its structures have been deallocated. |
| 1755 | gzclose must not be called more than once on the same file, just as free |
| 1756 | must not be called more than once on the same allocation. |
| 1757 | |
| 1758 | gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a |
| 1759 | file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the |
| 1760 | last read ended in the middle of a gzip stream, or Z_OK on success. |
| 1761 | */ |
| 1762 | |
| 1763 | ZEXTERN int ZEXPORT gzclose_r(gzFile file); |
| 1764 | ZEXTERN int ZEXPORT gzclose_w(gzFile file); |
| 1765 | /* |
| 1766 | Same as gzclose(), but gzclose_r() is only for use when reading, and |
| 1767 | gzclose_w() is only for use when writing or appending. The advantage to |
| 1768 | using these instead of gzclose() is that they avoid linking in zlib |
| 1769 | compression or decompression code that is not used when only reading or only |
| 1770 | writing respectively. If gzclose() is used, then both compression and |
| 1771 | decompression code will be included the application when linking to a static |
| 1772 | zlib library. |
| 1773 | */ |
| 1774 | |
| 1775 | ZEXTERN const char * ZEXPORT gzerror(gzFile file, int *errnum); |
| 1776 | /* |
| 1777 | Return the error message for the last error which occurred on file. |
| 1778 | If errnum is not NULL, *errnum is set to zlib error number. If an error |
| 1779 | occurred in the file system and not in the compression library, *errnum is |
| 1780 | set to Z_ERRNO and the application may consult errno to get the exact error |
| 1781 | code. |
| 1782 | |
| 1783 | The application must not modify the returned string. Future calls to |
| 1784 | this function may invalidate the previously returned string. If file is |
| 1785 | closed, then the string previously returned by gzerror will no longer be |
| 1786 | available. |
| 1787 | |
| 1788 | gzerror() should be used to distinguish errors from end-of-file for those |
| 1789 | functions above that do not distinguish those cases in their return values. |
| 1790 | */ |
| 1791 | |
| 1792 | ZEXTERN void ZEXPORT gzclearerr(gzFile file); |
| 1793 | /* |
| 1794 | Clear the error and end-of-file flags for file. This is analogous to the |
| 1795 | clearerr() function in stdio. This is useful for continuing to read a gzip |
| 1796 | file that is being written concurrently. |
| 1797 | */ |
| 1798 | |
| 1799 | #endif /* !Z_SOLO */ |
| 1800 | |
| 1801 | /* checksum functions */ |
| 1802 | |
| 1803 | /* |
| 1804 | These functions are not related to compression but are exported |
| 1805 | anyway because they might be useful in applications using the compression |
| 1806 | library. |
| 1807 | */ |
| 1808 | |
| 1809 | ZEXTERN uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len); |
| 1810 | /* |
| 1811 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
| 1812 | return the updated checksum. An Adler-32 value is in the range of a 32-bit |
| 1813 | unsigned integer. If buf is Z_NULL, this function returns the required |
| 1814 | initial value for the checksum. |
| 1815 | |
| 1816 | An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed |
| 1817 | much faster. |
| 1818 | |
| 1819 | Usage example: |
| 1820 | |
| 1821 | uLong adler = adler32(0L, Z_NULL, 0); |
| 1822 | |
| 1823 | while (read_buffer(buffer, length) != EOF) { |
| 1824 | adler = adler32(adler, buffer, length); |
| 1825 | } |
| 1826 | if (adler != original_adler) error(); |
| 1827 | */ |
| 1828 | |
| 1829 | ZEXTERN uLong ZEXPORT adler32_z(uLong adler, const Bytef *buf, |
| 1830 | z_size_t len); |
| 1831 | /* |
| 1832 | Same as adler32(), but with a size_t length. Note that a long is 32 bits |
| 1833 | on Windows. |
| 1834 | */ |
| 1835 | |
| 1836 | /* |
| 1837 | ZEXTERN uLong ZEXPORT adler32_combine(uLong adler1, uLong adler2, |
| 1838 | z_off_t len2); |
| 1839 | |
| 1840 | Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 |
| 1841 | and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for |
| 1842 | each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of |
| 1843 | seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note |
| 1844 | that the z_off_t type (like off_t) is a signed integer. If len2 is |
| 1845 | negative, the result has no meaning or utility. |
| 1846 | */ |
| 1847 | |
| 1848 | ZEXTERN uLong ZEXPORT crc32(uLong crc, const Bytef *buf, uInt len); |
| 1849 | /* |
| 1850 | Update a running CRC-32 with the bytes buf[0..len-1] and return the |
| 1851 | updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer. |
| 1852 | If buf is Z_NULL, this function returns the required initial value for the |
| 1853 | crc. Pre- and post-conditioning (one's complement) is performed within this |
| 1854 | function so it shouldn't be done by the application. |
| 1855 | |
| 1856 | Usage example: |
| 1857 | |
| 1858 | uLong crc = crc32(0L, Z_NULL, 0); |
| 1859 | |
| 1860 | while (read_buffer(buffer, length) != EOF) { |
| 1861 | crc = crc32(crc, buffer, length); |
| 1862 | } |
| 1863 | if (crc != original_crc) error(); |
| 1864 | */ |
| 1865 | |
| 1866 | ZEXTERN uLong ZEXPORT crc32_z(uLong crc, const Bytef *buf, |
| 1867 | z_size_t len); |
| 1868 | /* |
| 1869 | Same as crc32(), but with a size_t length. Note that a long is 32 bits on |
| 1870 | Windows. |
| 1871 | */ |
| 1872 | |
| 1873 | /* |
| 1874 | ZEXTERN uLong ZEXPORT crc32_combine(uLong crc1, uLong crc2, z_off_t len2); |
| 1875 | |
| 1876 | Combine two CRC-32 check values into one. For two sequences of bytes, |
| 1877 | seq1 and seq2 with lengths len1 and len2, CRC-32 check values were |
| 1878 | calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 |
| 1879 | check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and |
| 1880 | len2. len2 must be non-negative, otherwise zero is returned. |
| 1881 | */ |
| 1882 | |
| 1883 | /* |
| 1884 | ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t len2); |
| 1885 | |
| 1886 | Return the operator corresponding to length len2, to be used with |
| 1887 | crc32_combine_op(). len2 must be non-negative, otherwise zero is returned. |
| 1888 | */ |
| 1889 | |
| 1890 | ZEXTERN uLong ZEXPORT crc32_combine_op(uLong crc1, uLong crc2, uLong op); |
| 1891 | /* |
| 1892 | Give the same result as crc32_combine(), using op in place of len2. op is |
| 1893 | is generated from len2 by crc32_combine_gen(). This will be faster than |
| 1894 | crc32_combine() if the generated op is used more than once. |
| 1895 | */ |
| 1896 | |
| 1897 | |
| 1898 | /* various hacks, don't look :) */ |
| 1899 | |
| 1900 | /* deflateInit and inflateInit are macros to allow checking the zlib version |
| 1901 | * and the compiler's view of z_stream: |
| 1902 | */ |
| 1903 | ZEXTERN int ZEXPORT deflateInit_(z_streamp strm, int level, |
| 1904 | const char *version, int stream_size); |
| 1905 | ZEXTERN int ZEXPORT inflateInit_(z_streamp strm, |
| 1906 | const char *version, int stream_size); |
| 1907 | ZEXTERN int ZEXPORT deflateInit2_(z_streamp strm, int level, int method, |
| 1908 | int windowBits, int memLevel, |
| 1909 | int strategy, const char *version, |
| 1910 | int stream_size); |
| 1911 | ZEXTERN int ZEXPORT inflateInit2_(z_streamp strm, int windowBits, |
| 1912 | const char *version, int stream_size); |
| 1913 | ZEXTERN int ZEXPORT inflateBackInit_(z_streamp strm, int windowBits, |
| 1914 | unsigned char FAR *window, |
| 1915 | const char *version, |
| 1916 | int stream_size); |
| 1917 | #ifdef Z_PREFIX_SET |
| 1918 | # define z_deflateInit(strm, level) \ |
| 1919 | deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) |
| 1920 | # define z_inflateInit(strm) \ |
| 1921 | inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) |
| 1922 | # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
| 1923 | deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
| 1924 | (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) |
| 1925 | # define z_inflateInit2(strm, windowBits) \ |
| 1926 | inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ |
| 1927 | (int)sizeof(z_stream)) |
| 1928 | # define z_inflateBackInit(strm, windowBits, window) \ |
| 1929 | inflateBackInit_((strm), (windowBits), (window), \ |
| 1930 | ZLIB_VERSION, (int)sizeof(z_stream)) |
| 1931 | #else |
| 1932 | # define deflateInit(strm, level) \ |
| 1933 | deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) |
| 1934 | # define inflateInit(strm) \ |
| 1935 | inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) |
| 1936 | # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
| 1937 | deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
| 1938 | (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) |
| 1939 | # define inflateInit2(strm, windowBits) \ |
| 1940 | inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ |
| 1941 | (int)sizeof(z_stream)) |
| 1942 | # define inflateBackInit(strm, windowBits, window) \ |
| 1943 | inflateBackInit_((strm), (windowBits), (window), \ |
| 1944 | ZLIB_VERSION, (int)sizeof(z_stream)) |
| 1945 | #endif |
| 1946 | |
| 1947 | #ifndef Z_SOLO |
| 1948 | |
| 1949 | /* gzgetc() macro and its supporting function and exposed data structure. Note |
| 1950 | * that the real internal state is much larger than the exposed structure. |
| 1951 | * This abbreviated structure exposes just enough for the gzgetc() macro. The |
| 1952 | * user should not mess with these exposed elements, since their names or |
| 1953 | * behavior could change in the future, perhaps even capriciously. They can |
| 1954 | * only be used by the gzgetc() macro. You have been warned. |
| 1955 | */ |
| 1956 | struct gzFile_s { |
| 1957 | unsigned have; |
| 1958 | unsigned char *next; |
| 1959 | z_off64_t pos; |
| 1960 | }; |
| 1961 | ZEXTERN int ZEXPORT gzgetc_(gzFile file); /* backward compatibility */ |
| 1962 | #ifdef Z_PREFIX_SET |
| 1963 | # undef z_gzgetc |
| 1964 | # define z_gzgetc(g) \ |
| 1965 | ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) |
| 1966 | #else |
| 1967 | # define gzgetc(g) \ |
| 1968 | ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) |
| 1969 | #endif |
| 1970 | |
| 1971 | /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or |
| 1972 | * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if |
| 1973 | * both are true, the application gets the *64 functions, and the regular |
| 1974 | * functions are changed to 64 bits) -- in case these are set on systems |
| 1975 | * without large file support, _LFS64_LARGEFILE must also be true |
| 1976 | */ |
| 1977 | #ifdef Z_LARGE64 |
| 1978 | ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *); |
| 1979 | ZEXTERN z_off64_t ZEXPORT gzseek64(gzFile, z_off64_t, int); |
| 1980 | ZEXTERN z_off64_t ZEXPORT gztell64(gzFile); |
| 1981 | ZEXTERN z_off64_t ZEXPORT gzoffset64(gzFile); |
| 1982 | ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off64_t); |
| 1983 | ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off64_t); |
| 1984 | ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off64_t); |
| 1985 | #endif |
| 1986 | |
| 1987 | #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) |
| 1988 | # ifdef Z_PREFIX_SET |
| 1989 | # define z_gzopen z_gzopen64 |
| 1990 | # define z_gzseek z_gzseek64 |
| 1991 | # define z_gztell z_gztell64 |
| 1992 | # define z_gzoffset z_gzoffset64 |
| 1993 | # define z_adler32_combine z_adler32_combine64 |
| 1994 | # define z_crc32_combine z_crc32_combine64 |
| 1995 | # define z_crc32_combine_gen z_crc32_combine_gen64 |
| 1996 | # else |
| 1997 | # define gzopen gzopen64 |
| 1998 | # define gzseek gzseek64 |
| 1999 | # define gztell gztell64 |
| 2000 | # define gzoffset gzoffset64 |
| 2001 | # define adler32_combine adler32_combine64 |
| 2002 | # define crc32_combine crc32_combine64 |
| 2003 | # define crc32_combine_gen crc32_combine_gen64 |
| 2004 | # endif |
| 2005 | # ifndef Z_LARGE64 |
| 2006 | ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *); |
| 2007 | ZEXTERN z_off_t ZEXPORT gzseek64(gzFile, z_off_t, int); |
| 2008 | ZEXTERN z_off_t ZEXPORT gztell64(gzFile); |
| 2009 | ZEXTERN z_off_t ZEXPORT gzoffset64(gzFile); |
| 2010 | ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off64_t); |
| 2011 | ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off64_t); |
| 2012 | ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off64_t); |
| 2013 | # endif |
| 2014 | #else |
| 2015 | ZEXTERN gzFile ZEXPORT gzopen(const char *, const char *); |
| 2016 | ZEXTERN z_off_t ZEXPORT gzseek(gzFile, z_off_t, int); |
| 2017 | ZEXTERN z_off_t ZEXPORT gztell(gzFile); |
| 2018 | ZEXTERN z_off_t ZEXPORT gzoffset(gzFile); |
| 2019 | ZEXTERN uLong ZEXPORT adler32_combine(uLong, uLong, z_off_t); |
| 2020 | ZEXTERN uLong ZEXPORT crc32_combine(uLong, uLong, z_off_t); |
| 2021 | ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t); |
| 2022 | #endif |
| 2023 | |
| 2024 | #else /* Z_SOLO */ |
| 2025 | |
| 2026 | ZEXTERN uLong ZEXPORT adler32_combine(uLong, uLong, z_off_t); |
| 2027 | ZEXTERN uLong ZEXPORT crc32_combine(uLong, uLong, z_off_t); |
| 2028 | ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t); |
| 2029 | |
| 2030 | #endif /* !Z_SOLO */ |
| 2031 | |
| 2032 | /* undocumented functions */ |
| 2033 | ZEXTERN const char * ZEXPORT zError(int); |
| 2034 | ZEXTERN int ZEXPORT inflateSyncPoint(z_streamp); |
| 2035 | ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table(void); |
| 2036 | ZEXTERN int ZEXPORT inflateUndermine(z_streamp, int); |
| 2037 | ZEXTERN int ZEXPORT inflateValidate(z_streamp, int); |
| 2038 | ZEXTERN unsigned long ZEXPORT inflateCodesUsed(z_streamp); |
| 2039 | ZEXTERN int ZEXPORT inflateResetKeep(z_streamp); |
| 2040 | ZEXTERN int ZEXPORT deflateResetKeep(z_streamp); |
| 2041 | #if defined(_WIN32) && !defined(Z_SOLO) |
| 2042 | ZEXTERN gzFile ZEXPORT gzopen_w(const wchar_t *path, |
| 2043 | const char *mode); |
| 2044 | #endif |
| 2045 | #if defined(STDC) || defined(Z_HAVE_STDARG_H) |
| 2046 | # ifndef Z_SOLO |
| 2047 | ZEXTERN int ZEXPORTVA gzvprintf(gzFile file, |
| 2048 | const char *format, |
| 2049 | va_list va); |
| 2050 | # endif |
| 2051 | #endif |
| 2052 | |
| 2053 | #ifdef __cplusplus |
| 2054 | } |
| 2055 | #endif |
| 2056 | |
| 2057 | #endif /* ZLIB_H */ |
| 2058 |
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