1 #ifndef ZNGLIB_H_ 2 #define ZNGLIB_H_ 3 /* zlib-ng.h -- interface of the 'zlib-ng' compression library, forked from zlib. 4 5 Copyright (C) 1995-2016 Jean-loup Gailly and Mark Adler 6 7 This software is provided 'as-is', without any express or implied 8 warranty. In no event will the authors be held liable for any damages 9 arising from the use of this software. 10 11 Permission is granted to anyone to use this software for any purpose, 12 including commercial applications, and to alter it and redistribute it 13 freely, subject to the following restrictions: 14 15 1. The origin of this software must not be misrepresented; you must not 16 claim that you wrote the original software. If you use this software 17 in a product, an acknowledgment in the product documentation would be 18 appreciated but is not required. 19 2. Altered source versions must be plainly marked as such, and must not be 20 misrepresented as being the original software. 21 3. This notice may not be removed or altered from any source distribution. 22 23 Jean-loup Gailly Mark Adler 24 jloup@gzip.org madler@alumni.caltech.edu 25 26 27 The data format used by the zlib library is described by RFCs (Request for 28 Comments) 1950 to 1952 in the files https://tools.ietf.org/html/rfc1950 29 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 30 */ 31 32 #ifdef ZLIB_H_ 33 # error Include zlib-ng.h for zlib-ng API or zlib.h for zlib-compat API but not both 34 #endif 35 36 #include <stdint.h> 37 #include "zconf-ng.h" 38 39 #ifndef ZCONFNG_H 40 # error Missing zconf-ng.h add binary output directory to include directories 41 #endif 42 43 #ifdef __cplusplus 44 extern "C" { 45 #endif 46 47 #define ZLIBNG_VERSION "2.0.5" 48 #define ZLIBNG_VERNUM 0x2050 49 #define ZLIBNG_VER_MAJOR 2 50 #define ZLIBNG_VER_MINOR 0 51 #define ZLIBNG_VER_REVISION 5 52 #define ZLIBNG_VER_SUBREVISION 0 53 54 /* 55 The 'zlib' compression library provides in-memory compression and 56 decompression functions, including integrity checks of the uncompressed data. 57 This version of the library supports only one compression method (deflation) 58 but other algorithms will be added later and will have the same stream 59 interface. 60 61 Compression can be done in a single step if the buffers are large enough, 62 or can be done by repeated calls of the compression function. In the latter 63 case, the application must provide more input and/or consume the output 64 (providing more output space) before each call. 65 66 The compressed data format used by default by the in-memory functions is 67 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 68 around a deflate stream, which is itself documented in RFC 1951. 69 70 The library also supports reading and writing files in gzip (.gz) format 71 with an interface similar to that of stdio using the functions that start 72 with "gz". The gzip format is different from the zlib format. gzip is a 73 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 74 75 This library can optionally read and write gzip and raw deflate streams in 76 memory as well. 77 78 The zlib format was designed to be compact and fast for use in memory 79 and on communications channels. The gzip format was designed for single- 80 file compression on file systems, has a larger header than zlib to maintain 81 directory information, and uses a different, slower check method than zlib. 82 83 The library does not install any signal handler. The decoder checks 84 the consistency of the compressed data, so the library should never crash 85 even in the case of corrupted input. 86 */ 87 88 typedef void *(*alloc_func) (void *opaque, unsigned int items, unsigned int size); 89 typedef void (*free_func) (void *opaque, void *address); 90 91 struct internal_state; 92 93 typedef struct zng_stream_s { 94 const uint8_t *next_in; /* next input byte */ 95 uint32_t avail_in; /* number of bytes available at next_in */ 96 size_t total_in; /* total number of input bytes read so far */ 97 98 uint8_t *next_out; /* next output byte will go here */ 99 uint32_t avail_out; /* remaining free space at next_out */ 100 size_t total_out; /* total number of bytes output so far */ 101 102 const char *msg; /* last error message, NULL if no error */ 103 struct internal_state *state; /* not visible by applications */ 104 105 alloc_func zalloc; /* used to allocate the internal state */ 106 free_func zfree; /* used to free the internal state */ 107 void *opaque; /* private data object passed to zalloc and zfree */ 108 109 int data_type; /* best guess about the data type: binary or text 110 for deflate, or the decoding state for inflate */ 111 uint32_t adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 112 unsigned long reserved; /* reserved for future use */ 113 } zng_stream; 114 115 typedef zng_stream *zng_streamp; /* Obsolete type, retained for compatibility only */ 116 117 /* 118 gzip header information passed to and from zlib routines. See RFC 1952 119 for more details on the meanings of these fields. 120 */ 121 typedef struct zng_gz_header_s { 122 int32_t text; /* true if compressed data believed to be text */ 123 unsigned long time; /* modification time */ 124 int32_t xflags; /* extra flags (not used when writing a gzip file) */ 125 int32_t os; /* operating system */ 126 uint8_t *extra; /* pointer to extra field or NULL if none */ 127 uint32_t extra_len; /* extra field length (valid if extra != NULL) */ 128 uint32_t extra_max; /* space at extra (only when reading header) */ 129 uint8_t *name; /* pointer to zero-terminated file name or NULL */ 130 uint32_t name_max; /* space at name (only when reading header) */ 131 uint8_t *comment; /* pointer to zero-terminated comment or NULL */ 132 uint32_t comm_max; /* space at comment (only when reading header) */ 133 int32_t hcrc; /* true if there was or will be a header crc */ 134 int32_t done; /* true when done reading gzip header (not used when writing a gzip file) */ 135 } zng_gz_header; 136 137 typedef zng_gz_header *zng_gz_headerp; 138 139 /* 140 The application must update next_in and avail_in when avail_in has dropped 141 to zero. It must update next_out and avail_out when avail_out has dropped 142 to zero. The application must initialize zalloc, zfree and opaque before 143 calling the init function. All other fields are set by the compression 144 library and must not be updated by the application. 145 146 The opaque value provided by the application will be passed as the first 147 parameter for calls of zalloc and zfree. This can be useful for custom 148 memory management. The compression library attaches no meaning to the 149 opaque value. 150 151 zalloc must return NULL if there is not enough memory for the object. 152 If zlib is used in a multi-threaded application, zalloc and zfree must be 153 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 154 Z_NULL on entry to the initialization function, they are set to internal 155 routines that use the standard library functions malloc() and free(). 156 157 The fields total_in and total_out can be used for statistics or progress 158 reports. After compression, total_in holds the total size of the 159 uncompressed data and may be saved for use by the decompressor (particularly 160 if the decompressor wants to decompress everything in a single step). 161 */ 162 163 /* constants */ 164 165 #define Z_NO_FLUSH 0 166 #define Z_PARTIAL_FLUSH 1 167 #define Z_SYNC_FLUSH 2 168 #define Z_FULL_FLUSH 3 169 #define Z_FINISH 4 170 #define Z_BLOCK 5 171 #define Z_TREES 6 172 /* Allowed flush values; see deflate() and inflate() below for details */ 173 174 #define Z_OK 0 175 #define Z_STREAM_END 1 176 #define Z_NEED_DICT 2 177 #define Z_ERRNO (-1) 178 #define Z_STREAM_ERROR (-2) 179 #define Z_DATA_ERROR (-3) 180 #define Z_MEM_ERROR (-4) 181 #define Z_BUF_ERROR (-5) 182 #define Z_VERSION_ERROR (-6) 183 /* Return codes for the compression/decompression functions. Negative values 184 * are errors, positive values are used for special but normal events. 185 */ 186 187 #define Z_NO_COMPRESSION 0 188 #define Z_BEST_SPEED 1 189 #define Z_BEST_COMPRESSION 9 190 #define Z_DEFAULT_COMPRESSION (-1) 191 /* compression levels */ 192 193 #define Z_FILTERED 1 194 #define Z_HUFFMAN_ONLY 2 195 #define Z_RLE 3 196 #define Z_FIXED 4 197 #define Z_DEFAULT_STRATEGY 0 198 /* compression strategy; see deflateInit2() below for details */ 199 200 #define Z_BINARY 0 201 #define Z_TEXT 1 202 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 203 #define Z_UNKNOWN 2 204 /* Possible values of the data_type field for deflate() */ 205 206 #define Z_DEFLATED 8 207 /* The deflate compression method (the only one supported in this version) */ 208 209 #define Z_NULL NULL /* for compatibility with zlib, was for initializing zalloc, zfree, opaque */ 210 211 212 /* basic functions */ 213 214 Z_EXTERN Z_EXPORT 215 const char *zlibng_version(void); 216 /* The application can compare zlibng_version and ZLIBNG_VERSION for consistency. 217 If the first character differs, the library code actually used is not 218 compatible with the zlib-ng.h header file used by the application. This check 219 is automatically made by deflateInit and inflateInit. 220 */ 221 222 /* 223 Z_EXTERN Z_EXPORT 224 int zng_deflateInit(zng_stream *strm, int level); 225 226 Initializes the internal stream state for compression. The fields 227 zalloc, zfree and opaque must be initialized before by the caller. If 228 zalloc and zfree are set to NULL, deflateInit updates them to use default 229 allocation functions. 230 231 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 232 1 gives best speed, 9 gives best compression, 0 gives no compression at all 233 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 234 requests a default compromise between speed and compression (currently 235 equivalent to level 6). 236 237 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 238 memory, Z_STREAM_ERROR if level is not a valid compression level, or 239 Z_VERSION_ERROR if the zlib library version (zng_version) is incompatible 240 with the version assumed by the caller (ZLIBNG_VERSION). msg is set to null 241 if there is no error message. deflateInit does not perform any compression: 242 this will be done by deflate(). 243 */ 244 245 246 Z_EXTERN Z_EXPORT 247 int32_t zng_deflate(zng_stream *strm, int32_t flush); 248 /* 249 deflate compresses as much data as possible, and stops when the input 250 buffer becomes empty or the output buffer becomes full. It may introduce 251 some output latency (reading input without producing any output) except when 252 forced to flush. 253 254 The detailed semantics are as follows. deflate performs one or both of the 255 following actions: 256 257 - Compress more input starting at next_in and update next_in and avail_in 258 accordingly. If not all input can be processed (because there is not 259 enough room in the output buffer), next_in and avail_in are updated and 260 processing will resume at this point for the next call of deflate(). 261 262 - Generate more output starting at next_out and update next_out and avail_out 263 accordingly. This action is forced if the parameter flush is non zero. 264 Forcing flush frequently degrades the compression ratio, so this parameter 265 should be set only when necessary. Some output may be provided even if 266 flush is zero. 267 268 Before the call of deflate(), the application should ensure that at least 269 one of the actions is possible, by providing more input and/or consuming more 270 output, and updating avail_in or avail_out accordingly; avail_out should 271 never be zero before the call. The application can consume the compressed 272 output when it wants, for example when the output buffer is full (avail_out 273 == 0), or after each call of deflate(). If deflate returns Z_OK and with 274 zero avail_out, it must be called again after making room in the output 275 buffer because there might be more output pending. See deflatePending(), 276 which can be used if desired to determine whether or not there is more output 277 in that case. 278 279 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 280 decide how much data to accumulate before producing output, in order to 281 maximize compression. 282 283 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 284 flushed to the output buffer and the output is aligned on a byte boundary, so 285 that the decompressor can get all input data available so far. (In 286 particular avail_in is zero after the call if enough output space has been 287 provided before the call.) Flushing may degrade compression for some 288 compression algorithms and so it should be used only when necessary. This 289 completes the current deflate block and follows it with an empty stored block 290 that is three bits plus filler bits to the next byte, followed by four bytes 291 (00 00 ff ff). 292 293 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 294 output buffer, but the output is not aligned to a byte boundary. All of the 295 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 296 This completes the current deflate block and follows it with an empty fixed 297 codes block that is 10 bits long. This assures that enough bytes are output 298 in order for the decompressor to finish the block before the empty fixed 299 codes block. 300 301 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 302 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 303 seven bits of the current block are held to be written as the next byte after 304 the next deflate block is completed. In this case, the decompressor may not 305 be provided enough bits at this point in order to complete decompression of 306 the data provided so far to the compressor. It may need to wait for the next 307 block to be emitted. This is for advanced applications that need to control 308 the emission of deflate blocks. 309 310 If flush is set to Z_FULL_FLUSH, all output is flushed as with 311 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 312 restart from this point if previous compressed data has been damaged or if 313 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 314 compression. 315 316 If deflate returns with avail_out == 0, this function must be called again 317 with the same value of the flush parameter and more output space (updated 318 avail_out), until the flush is complete (deflate returns with non-zero 319 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 320 avail_out is greater than six to avoid repeated flush markers due to 321 avail_out == 0 on return. 322 323 If the parameter flush is set to Z_FINISH, pending input is processed, 324 pending output is flushed and deflate returns with Z_STREAM_END if there was 325 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 326 function must be called again with Z_FINISH and more output space (updated 327 avail_out) but no more input data, until it returns with Z_STREAM_END or an 328 error. After deflate has returned Z_STREAM_END, the only possible operations 329 on the stream are deflateReset or deflateEnd. 330 331 Z_FINISH can be used in the first deflate call after deflateInit if all the 332 compression is to be done in a single step. In order to complete in one 333 call, avail_out must be at least the value returned by deflateBound (see 334 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 335 output space is provided, deflate will not return Z_STREAM_END, and it must 336 be called again as described above. 337 338 deflate() sets strm->adler to the Adler-32 checksum of all input read 339 so far (that is, total_in bytes). If a gzip stream is being generated, then 340 strm->adler will be the CRC-32 checksum of the input read so far. (See 341 deflateInit2 below.) 342 343 deflate() may update strm->data_type if it can make a good guess about 344 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 345 considered binary. This field is only for information purposes and does not 346 affect the compression algorithm in any manner. 347 348 deflate() returns Z_OK if some progress has been made (more input 349 processed or more output produced), Z_STREAM_END if all input has been 350 consumed and all output has been produced (only when flush is set to 351 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 352 if next_in or next_out was NULL) or the state was inadvertently written over 353 by the application), or Z_BUF_ERROR if no progress is possible (for example 354 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 355 deflate() can be called again with more input and more output space to 356 continue compressing. 357 */ 358 359 360 Z_EXTERN Z_EXPORT 361 int32_t zng_deflateEnd(zng_stream *strm); 362 /* 363 All dynamically allocated data structures for this stream are freed. 364 This function discards any unprocessed input and does not flush any pending 365 output. 366 367 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 368 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 369 prematurely (some input or output was discarded). In the error case, msg 370 may be set but then points to a static string (which must not be 371 deallocated). 372 */ 373 374 375 /* 376 Z_EXTERN Z_EXPORT 377 int zng_inflateInit(zng_stream *strm); 378 379 Initializes the internal stream state for decompression. The fields 380 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 381 the caller. In the current version of inflate, the provided input is not 382 read or consumed. The allocation of a sliding window will be deferred to 383 the first call of inflate (if the decompression does not complete on the 384 first call). If zalloc and zfree are set to NULL, inflateInit updates 385 them to use default allocation functions. 386 387 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 388 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 389 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 390 invalid, such as a null pointer to the structure. msg is set to null if 391 there is no error message. inflateInit does not perform any decompression. 392 Actual decompression will be done by inflate(). So next_in, and avail_in, 393 next_out, and avail_out are unused and unchanged. The current 394 implementation of inflateInit() does not process any header information -- 395 that is deferred until inflate() is called. 396 */ 397 398 399 Z_EXTERN Z_EXPORT 400 int32_t zng_inflate(zng_stream *strm, int32_t flush); 401 /* 402 inflate decompresses as much data as possible, and stops when the input 403 buffer becomes empty or the output buffer becomes full. It may introduce 404 some output latency (reading input without producing any output) except when 405 forced to flush. 406 407 The detailed semantics are as follows. inflate performs one or both of the 408 following actions: 409 410 - Decompress more input starting at next_in and update next_in and avail_in 411 accordingly. If not all input can be processed (because there is not 412 enough room in the output buffer), then next_in and avail_in are updated 413 accordingly, and processing will resume at this point for the next call of 414 inflate(). 415 416 - Generate more output starting at next_out and update next_out and avail_out 417 accordingly. inflate() provides as much output as possible, until there is 418 no more input data or no more space in the output buffer (see below about 419 the flush parameter). 420 421 Before the call of inflate(), the application should ensure that at least 422 one of the actions is possible, by providing more input and/or consuming more 423 output, and updating the next_* and avail_* values accordingly. If the 424 caller of inflate() does not provide both available input and available 425 output space, it is possible that there will be no progress made. The 426 application can consume the uncompressed output when it wants, for example 427 when the output buffer is full (avail_out == 0), or after each call of 428 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 429 called again after making room in the output buffer because there might be 430 more output pending. 431 432 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 433 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 434 output as possible to the output buffer. Z_BLOCK requests that inflate() 435 stop if and when it gets to the next deflate block boundary. When decoding 436 the zlib or gzip format, this will cause inflate() to return immediately 437 after the header and before the first block. When doing a raw inflate, 438 inflate() will go ahead and process the first block, and will return when it 439 gets to the end of that block, or when it runs out of data. 440 441 The Z_BLOCK option assists in appending to or combining deflate streams. 442 To assist in this, on return inflate() always sets strm->data_type to the 443 number of unused bits in the last byte taken from strm->next_in, plus 64 if 444 inflate() is currently decoding the last block in the deflate stream, plus 445 128 if inflate() returned immediately after decoding an end-of-block code or 446 decoding the complete header up to just before the first byte of the deflate 447 stream. The end-of-block will not be indicated until all of the uncompressed 448 data from that block has been written to strm->next_out. The number of 449 unused bits may in general be greater than seven, except when bit 7 of 450 data_type is set, in which case the number of unused bits will be less than 451 eight. data_type is set as noted here every time inflate() returns for all 452 flush options, and so can be used to determine the amount of currently 453 consumed input in bits. 454 455 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 456 end of each deflate block header is reached, before any actual data in that 457 block is decoded. This allows the caller to determine the length of the 458 deflate block header for later use in random access within a deflate block. 459 256 is added to the value of strm->data_type when inflate() returns 460 immediately after reaching the end of the deflate block header. 461 462 inflate() should normally be called until it returns Z_STREAM_END or an 463 error. However if all decompression is to be performed in a single step (a 464 single call of inflate), the parameter flush should be set to Z_FINISH. In 465 this case all pending input is processed and all pending output is flushed; 466 avail_out must be large enough to hold all of the uncompressed data for the 467 operation to complete. (The size of the uncompressed data may have been 468 saved by the compressor for this purpose.) The use of Z_FINISH is not 469 required to perform an inflation in one step. However it may be used to 470 inform inflate that a faster approach can be used for the single inflate() 471 call. Z_FINISH also informs inflate to not maintain a sliding window if the 472 stream completes, which reduces inflate's memory footprint. If the stream 473 does not complete, either because not all of the stream is provided or not 474 enough output space is provided, then a sliding window will be allocated and 475 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 476 been used. 477 478 In this implementation, inflate() always flushes as much output as 479 possible to the output buffer, and always uses the faster approach on the 480 first call. So the effects of the flush parameter in this implementation are 481 on the return value of inflate() as noted below, when inflate() returns early 482 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 483 memory for a sliding window when Z_FINISH is used. 484 485 If a preset dictionary is needed after this call (see inflateSetDictionary 486 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 487 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 488 strm->adler to the Adler-32 checksum of all output produced so far (that is, 489 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 490 below. At the end of the stream, inflate() checks that its computed Adler-32 491 checksum is equal to that saved by the compressor and returns Z_STREAM_END 492 only if the checksum is correct. 493 494 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 495 deflate data. The header type is detected automatically, if requested when 496 initializing with inflateInit2(). Any information contained in the gzip 497 header is not retained unless inflateGetHeader() is used. When processing 498 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 499 produced so far. The CRC-32 is checked against the gzip trailer, as is the 500 uncompressed length, modulo 2^32. 501 502 inflate() returns Z_OK if some progress has been made (more input processed 503 or more output produced), Z_STREAM_END if the end of the compressed data has 504 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 505 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 506 corrupted (input stream not conforming to the zlib format or incorrect check 507 value, in which case strm->msg points to a string with a more specific 508 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 509 next_in or next_out was NULL, or the state was inadvertently written over 510 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 511 if no progress is possible or if there was not enough room in the output 512 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 513 inflate() can be called again with more input and more output space to 514 continue decompressing. If Z_DATA_ERROR is returned, the application may 515 then call inflateSync() to look for a good compression block if a partial 516 recovery of the data is to be attempted. 517 */ 518 519 520 Z_EXTERN Z_EXPORT 521 int32_t zng_inflateEnd(zng_stream *strm); 522 /* 523 All dynamically allocated data structures for this stream are freed. 524 This function discards any unprocessed input and does not flush any pending 525 output. 526 527 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 528 was inconsistent. 529 */ 530 531 532 /* Advanced functions */ 533 534 /* 535 The following functions are needed only in some special applications. 536 */ 537 538 /* 539 Z_EXTERN Z_EXPORT 540 int zng_deflateInit2(zng_stream *strm, int level, int method, int windowBits, int memLevel, int strategy); 541 542 This is another version of deflateInit with more compression options. The 543 fields zalloc, zfree and opaque must be initialized before by the caller. 544 545 The method parameter is the compression method. It must be Z_DEFLATED in 546 this version of the library. 547 548 The windowBits parameter is the base two logarithm of the window size 549 (the size of the history buffer). It should be in the range 8..15 for this 550 version of the library. Larger values of this parameter result in better 551 compression at the expense of memory usage. The default value is 15 if 552 deflateInit is used instead. 553 554 For the current implementation of deflate(), a windowBits value of 8 (a 555 window size of 256 bytes) is not supported. As a result, a request for 8 556 will result in 9 (a 512-byte window). In that case, providing 8 to 557 inflateInit2() will result in an error when the zlib header with 9 is 558 checked against the initialization of inflate(). The remedy is to not use 8 559 with deflateInit2() with this initialization, or at least in that case use 9 560 with inflateInit2(). 561 562 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 563 determines the window size. deflate() will then generate raw deflate data 564 with no zlib header or trailer, and will not compute a check value. 565 566 windowBits can also be greater than 15 for optional gzip encoding. Add 567 16 to windowBits to write a simple gzip header and trailer around the 568 compressed data instead of a zlib wrapper. The gzip header will have no 569 file name, no extra data, no comment, no modification time (set to zero), no 570 header crc, and the operating system will be set to the appropriate value, 571 if the operating system was determined at compile time. If a gzip stream is 572 being written, strm->adler is a CRC-32 instead of an Adler-32. 573 574 For raw deflate or gzip encoding, a request for a 256-byte window is 575 rejected as invalid, since only the zlib header provides a means of 576 transmitting the window size to the decompressor. 577 578 The memLevel parameter specifies how much memory should be allocated 579 for the internal compression state. memLevel=1 uses minimum memory but is 580 slow and reduces compression ratio; memLevel=9 uses maximum memory for 581 optimal speed. The default value is 8. See zconf.h for total memory usage 582 as a function of windowBits and memLevel. 583 584 The strategy parameter is used to tune the compression algorithm. Use the 585 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 586 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 587 string match), or Z_RLE to limit match distances to one (run-length 588 encoding). Filtered data consists mostly of small values with a somewhat 589 random distribution. In this case, the compression algorithm is tuned to 590 compress them better. The effect of Z_FILTERED is to force more Huffman 591 coding and less string matching; it is somewhat intermediate between 592 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 593 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 594 strategy parameter only affects the compression ratio but not the 595 correctness of the compressed output even if it is not set appropriately. 596 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 597 decoder for special applications. 598 599 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 600 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 601 method), or Z_VERSION_ERROR if the zlib library version (zng_version) is 602 incompatible with the version assumed by the caller (ZLIBNG_VERSION). msg is 603 set to null if there is no error message. deflateInit2 does not perform any 604 compression: this will be done by deflate(). 605 */ 606 607 Z_EXTERN Z_EXPORT 608 int32_t zng_deflateSetDictionary(zng_stream *strm, const uint8_t *dictionary, uint32_t dictLength); 609 /* 610 Initializes the compression dictionary from the given byte sequence 611 without producing any compressed output. When using the zlib format, this 612 function must be called immediately after deflateInit, deflateInit2 or 613 deflateReset, and before any call of deflate. When doing raw deflate, this 614 function must be called either before any call of deflate, or immediately 615 after the completion of a deflate block, i.e. after all input has been 616 consumed and all output has been delivered when using any of the flush 617 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 618 compressor and decompressor must use exactly the same dictionary (see 619 inflateSetDictionary). 620 621 The dictionary should consist of strings (byte sequences) that are likely 622 to be encountered later in the data to be compressed, with the most commonly 623 used strings preferably put towards the end of the dictionary. Using a 624 dictionary is most useful when the data to be compressed is short and can be 625 predicted with good accuracy; the data can then be compressed better than 626 with the default empty dictionary. 627 628 Depending on the size of the compression data structures selected by 629 deflateInit or deflateInit2, a part of the dictionary may in effect be 630 discarded, for example if the dictionary is larger than the window size 631 provided in deflateInit or deflateInit2. Thus the strings most likely to be 632 useful should be put at the end of the dictionary, not at the front. In 633 addition, the current implementation of deflate will use at most the window 634 size minus 262 bytes of the provided dictionary. 635 636 Upon return of this function, strm->adler is set to the Adler-32 value 637 of the dictionary; the decompressor may later use this value to determine 638 which dictionary has been used by the compressor. (The Adler-32 value 639 applies to the whole dictionary even if only a subset of the dictionary is 640 actually used by the compressor.) If a raw deflate was requested, then the 641 Adler-32 value is not computed and strm->adler is not set. 642 643 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 644 parameter is invalid (e.g. dictionary being NULL) or the stream state is 645 inconsistent (for example if deflate has already been called for this stream 646 or if not at a block boundary for raw deflate). deflateSetDictionary does 647 not perform any compression: this will be done by deflate(). 648 */ 649 650 Z_EXTERN Z_EXPORT 651 int32_t zng_deflateGetDictionary(zng_stream *strm, uint8_t *dictionary, uint32_t *dictLength); 652 /* 653 Returns the sliding dictionary being maintained by deflate. dictLength is 654 set to the number of bytes in the dictionary, and that many bytes are copied 655 to dictionary. dictionary must have enough space, where 32768 bytes is 656 always enough. If deflateGetDictionary() is called with dictionary equal to 657 Z_NULL, then only the dictionary length is returned, and nothing is copied. 658 Similarly, if dictLength is Z_NULL, then it is not set. 659 660 deflateGetDictionary() may return a length less than the window size, even 661 when more than the window size in input has been provided. It may return up 662 to 258 bytes less in that case, due to how zlib's implementation of deflate 663 manages the sliding window and lookahead for matches, where matches can be 664 up to 258 bytes long. If the application needs the last window-size bytes of 665 input, then that would need to be saved by the application outside of zlib. 666 667 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 668 stream state is inconsistent. 669 */ 670 671 Z_EXTERN Z_EXPORT 672 int32_t zng_deflateCopy(zng_stream *dest, zng_stream *source); 673 /* 674 Sets the destination stream as a complete copy of the source stream. 675 676 This function can be useful when several compression strategies will be 677 tried, for example when there are several ways of pre-processing the input 678 data with a filter. The streams that will be discarded should then be freed 679 by calling deflateEnd. Note that deflateCopy duplicates the internal 680 compression state which can be quite large, so this strategy is slow and can 681 consume lots of memory. 682 683 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 684 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 685 (such as zalloc being NULL). msg is left unchanged in both source and 686 destination. 687 */ 688 689 Z_EXTERN Z_EXPORT 690 int32_t zng_deflateReset(zng_stream *strm); 691 /* 692 This function is equivalent to deflateEnd followed by deflateInit, but 693 does not free and reallocate the internal compression state. The stream 694 will leave the compression level and any other attributes that may have been 695 set unchanged. 696 697 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 698 stream state was inconsistent (such as zalloc or state being NULL). 699 */ 700 701 Z_EXTERN Z_EXPORT 702 int32_t zng_deflateParams(zng_stream *strm, int32_t level, int32_t strategy); 703 /* 704 Dynamically update the compression level and compression strategy. The 705 interpretation of level and strategy is as in deflateInit2(). This can be 706 used to switch between compression and straight copy of the input data, or 707 to switch to a different kind of input data requiring a different strategy. 708 If the compression approach (which is a function of the level) or the 709 strategy is changed, and if there have been any deflate() calls since the 710 state was initialized or reset, then the input available so far is 711 compressed with the old level and strategy using deflate(strm, Z_BLOCK). 712 There are three approaches for the compression levels 0, 1..3, and 4..9 713 respectively. The new level and strategy will take effect at the next call 714 of deflate(). 715 716 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 717 not have enough output space to complete, then the parameter change will not 718 take effect. In this case, deflateParams() can be called again with the 719 same parameters and more output space to try again. 720 721 In order to assure a change in the parameters on the first try, the 722 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 723 request until strm.avail_out is not zero, before calling deflateParams(). 724 Then no more input data should be provided before the deflateParams() call. 725 If this is done, the old level and strategy will be applied to the data 726 compressed before deflateParams(), and the new level and strategy will be 727 applied to the the data compressed after deflateParams(). 728 729 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 730 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 731 there was not enough output space to complete the compression of the 732 available input data before a change in the strategy or approach. Note that 733 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 734 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 735 retried with more output space. 736 */ 737 738 Z_EXTERN Z_EXPORT 739 int32_t zng_deflateTune(zng_stream *strm, int32_t good_length, int32_t max_lazy, int32_t nice_length, int32_t max_chain); 740 /* 741 Fine tune deflate's internal compression parameters. This should only be 742 used by someone who understands the algorithm used by zlib's deflate for 743 searching for the best matching string, and even then only by the most 744 fanatic optimizer trying to squeeze out the last compressed bit for their 745 specific input data. Read the deflate.c source code for the meaning of the 746 max_lazy, good_length, nice_length, and max_chain parameters. 747 748 deflateTune() can be called after deflateInit() or deflateInit2(), and 749 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 750 */ 751 752 Z_EXTERN Z_EXPORT 753 unsigned long zng_deflateBound(zng_stream *strm, unsigned long sourceLen); 754 /* 755 deflateBound() returns an upper bound on the compressed size after 756 deflation of sourceLen bytes. It must be called after deflateInit() or 757 deflateInit2(), and after deflateSetHeader(), if used. This would be used 758 to allocate an output buffer for deflation in a single pass, and so would be 759 called before deflate(). If that first deflate() call is provided the 760 sourceLen input bytes, an output buffer allocated to the size returned by 761 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 762 to return Z_STREAM_END. Note that it is possible for the compressed size to 763 be larger than the value returned by deflateBound() if flush options other 764 than Z_FINISH or Z_NO_FLUSH are used. 765 */ 766 767 Z_EXTERN Z_EXPORT 768 int32_t zng_deflatePending(zng_stream *strm, uint32_t *pending, int32_t *bits); 769 /* 770 deflatePending() returns the number of bytes and bits of output that have 771 been generated, but not yet provided in the available output. The bytes not 772 provided would be due to the available output space having being consumed. 773 The number of bits of output not provided are between 0 and 7, where they 774 await more bits to join them in order to fill out a full byte. If pending 775 or bits are NULL, then those values are not set. 776 777 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 778 stream state was inconsistent. 779 */ 780 781 Z_EXTERN Z_EXPORT 782 int32_t zng_deflatePrime(zng_stream *strm, int32_t bits, int32_t value); 783 /* 784 deflatePrime() inserts bits in the deflate output stream. The intent 785 is that this function is used to start off the deflate output with the bits 786 leftover from a previous deflate stream when appending to it. As such, this 787 function can only be used for raw deflate, and must be used before the first 788 deflate() call after a deflateInit2() or deflateReset(). bits must be less 789 than or equal to 16, and that many of the least significant bits of value 790 will be inserted in the output. 791 792 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 793 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 794 source stream state was inconsistent. 795 */ 796 797 Z_EXTERN Z_EXPORT 798 int32_t zng_deflateSetHeader(zng_stream *strm, zng_gz_headerp head); 799 /* 800 deflateSetHeader() provides gzip header information for when a gzip 801 stream is requested by deflateInit2(). deflateSetHeader() may be called 802 after deflateInit2() or deflateReset() and before the first call of 803 deflate(). The text, time, os, extra field, name, and comment information 804 in the provided zng_gz_header structure are written to the gzip header (xflag is 805 ignored -- the extra flags are set according to the compression level). The 806 caller must assure that, if not NULL, name and comment are terminated with 807 a zero byte, and that if extra is not NULL, that extra_len bytes are 808 available there. If hcrc is true, a gzip header crc is included. Note that 809 the current versions of the command-line version of gzip (up through version 810 1.3.x) do not support header crc's, and will report that it is a "multi-part 811 gzip file" and give up. 812 813 If deflateSetHeader is not used, the default gzip header has text false, 814 the time set to zero, and os set to 255, with no extra, name, or comment 815 fields. The gzip header is returned to the default state by deflateReset(). 816 817 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 818 stream state was inconsistent. 819 */ 820 821 /* 822 Z_EXTERN Z_EXPORT 823 int zng_inflateInit2(zng_stream *strm, int windowBits); 824 825 This is another version of inflateInit with an extra parameter. The 826 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 827 before by the caller. 828 829 The windowBits parameter is the base two logarithm of the maximum window 830 size (the size of the history buffer). It should be in the range 8..15 for 831 this version of the library. The default value is 15 if inflateInit is used 832 instead. windowBits must be greater than or equal to the windowBits value 833 provided to deflateInit2() while compressing, or it must be equal to 15 if 834 deflateInit2() was not used. If a compressed stream with a larger window 835 size is given as input, inflate() will return with the error code 836 Z_DATA_ERROR instead of trying to allocate a larger window. 837 838 windowBits can also be zero to request that inflate use the window size in 839 the zlib header of the compressed stream. 840 841 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 842 determines the window size. inflate() will then process raw deflate data, 843 not looking for a zlib or gzip header, not generating a check value, and not 844 looking for any check values for comparison at the end of the stream. This 845 is for use with other formats that use the deflate compressed data format 846 such as zip. Those formats provide their own check values. If a custom 847 format is developed using the raw deflate format for compressed data, it is 848 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 849 the uncompressed data as is done in the zlib, gzip, and zip formats. For 850 most applications, the zlib format should be used as is. Note that comments 851 above on the use in deflateInit2() applies to the magnitude of windowBits. 852 853 windowBits can also be greater than 15 for optional gzip decoding. Add 854 32 to windowBits to enable zlib and gzip decoding with automatic header 855 detection, or add 16 to decode only the gzip format (the zlib format will 856 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 857 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 858 below), inflate() will *not* automatically decode concatenated gzip members. 859 inflate() will return Z_STREAM_END at the end of the gzip member. The state 860 would need to be reset to continue decoding a subsequent gzip member. This 861 *must* be done if there is more data after a gzip member, in order for the 862 decompression to be compliant with the gzip standard (RFC 1952). 863 864 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 865 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 866 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 867 invalid, such as a null pointer to the structure. msg is set to null if 868 there is no error message. inflateInit2 does not perform any decompression 869 apart from possibly reading the zlib header if present: actual decompression 870 will be done by inflate(). (So next_in and avail_in may be modified, but 871 next_out and avail_out are unused and unchanged.) The current implementation 872 of inflateInit2() does not process any header information -- that is 873 deferred until inflate() is called. 874 */ 875 876 Z_EXTERN Z_EXPORT 877 int32_t zng_inflateSetDictionary(zng_stream *strm, const uint8_t *dictionary, uint32_t dictLength); 878 /* 879 Initializes the decompression dictionary from the given uncompressed byte 880 sequence. This function must be called immediately after a call of inflate, 881 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 882 can be determined from the Adler-32 value returned by that call of inflate. 883 The compressor and decompressor must use exactly the same dictionary (see 884 deflateSetDictionary). For raw inflate, this function can be called at any 885 time to set the dictionary. If the provided dictionary is smaller than the 886 window and there is already data in the window, then the provided dictionary 887 will amend what's there. The application must insure that the dictionary 888 that was used for compression is provided. 889 890 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 891 parameter is invalid (e.g. dictionary being NULL) or the stream state is 892 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 893 expected one (incorrect Adler-32 value). inflateSetDictionary does not 894 perform any decompression: this will be done by subsequent calls of 895 inflate(). 896 */ 897 898 Z_EXTERN Z_EXPORT 899 int32_t zng_inflateGetDictionary(zng_stream *strm, uint8_t *dictionary, uint32_t *dictLength); 900 /* 901 Returns the sliding dictionary being maintained by inflate. dictLength is 902 set to the number of bytes in the dictionary, and that many bytes are copied 903 to dictionary. dictionary must have enough space, where 32768 bytes is 904 always enough. If inflateGetDictionary() is called with dictionary equal to 905 NULL, then only the dictionary length is returned, and nothing is copied. 906 Similarly, if dictLength is NULL, then it is not set. 907 908 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 909 stream state is inconsistent. 910 */ 911 912 Z_EXTERN Z_EXPORT 913 int32_t zng_inflateSync(zng_stream *strm); 914 /* 915 Skips invalid compressed data until a possible full flush point (see above 916 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 917 available input is skipped. No output is provided. 918 919 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 920 All full flush points have this pattern, but not all occurrences of this 921 pattern are full flush points. 922 923 inflateSync returns Z_OK if a possible full flush point has been found, 924 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 925 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 926 In the success case, the application may save the current current value of 927 total_in which indicates where valid compressed data was found. In the 928 error case, the application may repeatedly call inflateSync, providing more 929 input each time, until success or end of the input data. 930 */ 931 932 Z_EXTERN Z_EXPORT 933 int32_t zng_inflateCopy(zng_stream *dest, zng_stream *source); 934 /* 935 Sets the destination stream as a complete copy of the source stream. 936 937 This function can be useful when randomly accessing a large stream. The 938 first pass through the stream can periodically record the inflate state, 939 allowing restarting inflate at those points when randomly accessing the 940 stream. 941 942 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 943 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 944 (such as zalloc being NULL). msg is left unchanged in both source and 945 destination. 946 */ 947 948 Z_EXTERN Z_EXPORT 949 int32_t zng_inflateReset(zng_stream *strm); 950 /* 951 This function is equivalent to inflateEnd followed by inflateInit, 952 but does not free and reallocate the internal decompression state. The 953 stream will keep attributes that may have been set by inflateInit2. 954 955 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 956 stream state was inconsistent (such as zalloc or state being NULL). 957 */ 958 959 Z_EXTERN Z_EXPORT 960 int32_t zng_inflateReset2(zng_stream *strm, int32_t windowBits); 961 /* 962 This function is the same as inflateReset, but it also permits changing 963 the wrap and window size requests. The windowBits parameter is interpreted 964 the same as it is for inflateInit2. If the window size is changed, then the 965 memory allocated for the window is freed, and the window will be reallocated 966 by inflate() if needed. 967 968 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 969 stream state was inconsistent (such as zalloc or state being NULL), or if 970 the windowBits parameter is invalid. 971 */ 972 973 Z_EXTERN Z_EXPORT 974 int32_t zng_inflatePrime(zng_stream *strm, int32_t bits, int32_t value); 975 /* 976 This function inserts bits in the inflate input stream. The intent is 977 that this function is used to start inflating at a bit position in the 978 middle of a byte. The provided bits will be used before any bytes are used 979 from next_in. This function should only be used with raw inflate, and 980 should be used before the first inflate() call after inflateInit2() or 981 inflateReset(). bits must be less than or equal to 16, and that many of the 982 least significant bits of value will be inserted in the input. 983 984 If bits is negative, then the input stream bit buffer is emptied. Then 985 inflatePrime() can be called again to put bits in the buffer. This is used 986 to clear out bits leftover after feeding inflate a block description prior 987 to feeding inflate codes. 988 989 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 990 stream state was inconsistent. 991 */ 992 993 Z_EXTERN Z_EXPORT 994 long zng_inflateMark(zng_stream *strm); 995 /* 996 This function returns two values, one in the lower 16 bits of the return 997 value, and the other in the remaining upper bits, obtained by shifting the 998 return value down 16 bits. If the upper value is -1 and the lower value is 999 zero, then inflate() is currently decoding information outside of a block. 1000 If the upper value is -1 and the lower value is non-zero, then inflate is in 1001 the middle of a stored block, with the lower value equaling the number of 1002 bytes from the input remaining to copy. If the upper value is not -1, then 1003 it is the number of bits back from the current bit position in the input of 1004 the code (literal or length/distance pair) currently being processed. In 1005 that case the lower value is the number of bytes already emitted for that 1006 code. 1007 1008 A code is being processed if inflate is waiting for more input to complete 1009 decoding of the code, or if it has completed decoding but is waiting for 1010 more output space to write the literal or match data. 1011 1012 inflateMark() is used to mark locations in the input data for random 1013 access, which may be at bit positions, and to note those cases where the 1014 output of a code may span boundaries of random access blocks. The current 1015 location in the input stream can be determined from avail_in and data_type 1016 as noted in the description for the Z_BLOCK flush parameter for inflate. 1017 1018 inflateMark returns the value noted above, or -65536 if the provided 1019 source stream state was inconsistent. 1020 */ 1021 1022 Z_EXTERN Z_EXPORT 1023 int32_t zng_inflateGetHeader(zng_stream *strm, zng_gz_headerp head); 1024 /* 1025 inflateGetHeader() requests that gzip header information be stored in the 1026 provided zng_gz_header structure. inflateGetHeader() may be called after 1027 inflateInit2() or inflateReset(), and before the first call of inflate(). 1028 As inflate() processes the gzip stream, head->done is zero until the header 1029 is completed, at which time head->done is set to one. If a zlib stream is 1030 being decoded, then head->done is set to -1 to indicate that there will be 1031 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1032 used to force inflate() to return immediately after header processing is 1033 complete and before any actual data is decompressed. 1034 1035 The text, time, xflags, and os fields are filled in with the gzip header 1036 contents. hcrc is set to true if there is a header CRC. (The header CRC 1037 was valid if done is set to one.) If extra is not NULL, then extra_max 1038 contains the maximum number of bytes to write to extra. Once done is true, 1039 extra_len contains the actual extra field length, and extra contains the 1040 extra field, or that field truncated if extra_max is less than extra_len. 1041 If name is not NULL, then up to name_max characters are written there, 1042 terminated with a zero unless the length is greater than name_max. If 1043 comment is not NULL, then up to comm_max characters are written there, 1044 terminated with a zero unless the length is greater than comm_max. When any 1045 of extra, name, or comment are not NULL and the respective field is not 1046 present in the header, then that field is set to NULL to signal its 1047 absence. This allows the use of deflateSetHeader() with the returned 1048 structure to duplicate the header. However if those fields are set to 1049 allocated memory, then the application will need to save those pointers 1050 elsewhere so that they can be eventually freed. 1051 1052 If inflateGetHeader is not used, then the header information is simply 1053 discarded. The header is always checked for validity, including the header 1054 CRC if present. inflateReset() will reset the process to discard the header 1055 information. The application would need to call inflateGetHeader() again to 1056 retrieve the header from the next gzip stream. 1057 1058 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1059 stream state was inconsistent. 1060 */ 1061 1062 /* 1063 Z_EXTERN Z_EXPORT 1064 int zng_inflateBackInit(zng_stream *strm, int windowBits, unsigned char *window); 1065 1066 Initialize the internal stream state for decompression using inflateBack() 1067 calls. The fields zalloc, zfree and opaque in strm must be initialized 1068 before the call. If zalloc and zfree are NULL, then the default library- 1069 derived memory allocation routines are used. windowBits is the base two 1070 logarithm of the window size, in the range 8..15. window is a caller 1071 supplied buffer of that size. Except for special applications where it is 1072 assured that deflate was used with small window sizes, windowBits must be 15 1073 and a 32K byte window must be supplied to be able to decompress general 1074 deflate streams. 1075 1076 See inflateBack() for the usage of these routines. 1077 1078 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1079 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1080 allocated, or Z_VERSION_ERROR if the version of the library does not match 1081 the version of the header file. 1082 */ 1083 1084 typedef uint32_t (*in_func) (void *, const uint8_t * *); 1085 typedef int32_t (*out_func) (void *, uint8_t *, uint32_t); 1086 1087 Z_EXTERN Z_EXPORT 1088 int32_t zng_inflateBack(zng_stream *strm, in_func in, void *in_desc, out_func out, void *out_desc); 1089 /* 1090 inflateBack() does a raw inflate with a single call using a call-back 1091 interface for input and output. This is potentially more efficient than 1092 inflate() for file i/o applications, in that it avoids copying between the 1093 output and the sliding window by simply making the window itself the output 1094 buffer. inflate() can be faster on modern CPUs when used with large 1095 buffers. inflateBack() trusts the application to not change the output 1096 buffer passed by the output function, at least until inflateBack() returns. 1097 1098 inflateBackInit() must be called first to allocate the internal state 1099 and to initialize the state with the user-provided window buffer. 1100 inflateBack() may then be used multiple times to inflate a complete, raw 1101 deflate stream with each call. inflateBackEnd() is then called to free the 1102 allocated state. 1103 1104 A raw deflate stream is one with no zlib or gzip header or trailer. 1105 This routine would normally be used in a utility that reads zip or gzip 1106 files and writes out uncompressed files. The utility would decode the 1107 header and process the trailer on its own, hence this routine expects only 1108 the raw deflate stream to decompress. This is different from the default 1109 behavior of inflate(), which expects a zlib header and trailer around the 1110 deflate stream. 1111 1112 inflateBack() uses two subroutines supplied by the caller that are then 1113 called by inflateBack() for input and output. inflateBack() calls those 1114 routines until it reads a complete deflate stream and writes out all of the 1115 uncompressed data, or until it encounters an error. The function's 1116 parameters and return types are defined above in the in_func and out_func 1117 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1118 number of bytes of provided input, and a pointer to that input in buf. If 1119 there is no input available, in() must return zero -- buf is ignored in that 1120 case -- and inflateBack() will return a buffer error. inflateBack() will 1121 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 1122 out() should return zero on success, or non-zero on failure. If out() 1123 returns non-zero, inflateBack() will return with an error. Neither in() nor 1124 out() are permitted to change the contents of the window provided to 1125 inflateBackInit(), which is also the buffer that out() uses to write from. 1126 The length written by out() will be at most the window size. Any non-zero 1127 amount of input may be provided by in(). 1128 1129 For convenience, inflateBack() can be provided input on the first call by 1130 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1131 in() will be called. Therefore strm->next_in must be initialized before 1132 calling inflateBack(). If strm->next_in is NULL, then in() will be called 1133 immediately for input. If strm->next_in is not NULL, then strm->avail_in 1134 must also be initialized, and then if strm->avail_in is not zero, input will 1135 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1136 1137 The in_desc and out_desc parameters of inflateBack() is passed as the 1138 first parameter of in() and out() respectively when they are called. These 1139 descriptors can be optionally used to pass any information that the caller- 1140 supplied in() and out() functions need to do their job. 1141 1142 On return, inflateBack() will set strm->next_in and strm->avail_in to 1143 pass back any unused input that was provided by the last in() call. The 1144 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1145 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1146 in the deflate stream (in which case strm->msg is set to indicate the nature 1147 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1148 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1149 using strm->next_in which will be NULL only if in() returned an error. If 1150 strm->next_in is not NULL, then the Z_BUF_ERROR was due to out() returning 1151 non-zero. (in() will always be called before out(), so strm->next_in is 1152 assured to be defined if out() returns non-zero.) Note that inflateBack() 1153 cannot return Z_OK. 1154 */ 1155 1156 Z_EXTERN Z_EXPORT 1157 int32_t zng_inflateBackEnd(zng_stream *strm); 1158 /* 1159 All memory allocated by inflateBackInit() is freed. 1160 1161 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1162 state was inconsistent. 1163 */ 1164 1165 Z_EXTERN Z_EXPORT 1166 unsigned long zng_zlibCompileFlags(void); 1167 /* Return flags indicating compile-time options. 1168 1169 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1170 1.0: size of unsigned int 1171 3.2: size of unsigned long 1172 5.4: size of void * (pointer) 1173 7.6: size of z_off_t 1174 1175 Compiler, assembler, and debug options: 1176 8: ZLIB_DEBUG 1177 9: ASMV or ASMINF -- use ASM code 1178 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1179 11: 0 (reserved) 1180 1181 One-time table building (smaller code, but not thread-safe if true): 1182 12: BUILDFIXED -- build static block decoding tables when needed (not supported by zlib-ng) 1183 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1184 14,15: 0 (reserved) 1185 1186 Library content (indicates missing functionality): 1187 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1188 deflate code when not needed) 1189 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1190 and decode gzip streams (to avoid linking crc code) 1191 18-19: 0 (reserved) 1192 1193 Operation variations (changes in library functionality): 1194 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1195 21: FASTEST -- deflate algorithm with only one, lowest compression level 1196 22,23: 0 (reserved) 1197 1198 The sprintf variant used by gzprintf (zero is best): 1199 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1200 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1201 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1202 1203 Remainder: 1204 27-31: 0 (reserved) 1205 */ 1206 1207 1208 /* utility functions */ 1209 1210 /* 1211 The following utility functions are implemented on top of the basic 1212 stream-oriented functions. To simplify the interface, some default options 1213 are assumed (compression level and memory usage, standard memory allocation 1214 functions). The source code of these utility functions can be modified if 1215 you need special options. 1216 */ 1217 1218 Z_EXTERN Z_EXPORT 1219 int32_t zng_compress(uint8_t *dest, size_t *destLen, const uint8_t *source, size_t sourceLen); 1220 /* 1221 Compresses the source buffer into the destination buffer. sourceLen is 1222 the byte length of the source buffer. Upon entry, destLen is the total size 1223 of the destination buffer, which must be at least the value returned by 1224 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1225 compressed data. compress() is equivalent to compress2() with a level 1226 parameter of Z_DEFAULT_COMPRESSION. 1227 1228 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1229 enough memory, Z_BUF_ERROR if there was not enough room in the output 1230 buffer. 1231 */ 1232 1233 Z_EXTERN Z_EXPORT 1234 int32_t zng_compress2(uint8_t *dest, size_t *destLen, const uint8_t *source, size_t sourceLen, int32_t level); 1235 /* 1236 Compresses the source buffer into the destination buffer. The level 1237 parameter has the same meaning as in deflateInit. sourceLen is the byte 1238 length of the source buffer. Upon entry, destLen is the total size of the 1239 destination buffer, which must be at least the value returned by 1240 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1241 compressed data. 1242 1243 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1244 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1245 Z_STREAM_ERROR if the level parameter is invalid. 1246 */ 1247 1248 Z_EXTERN Z_EXPORT 1249 size_t zng_compressBound(size_t sourceLen); 1250 /* 1251 compressBound() returns an upper bound on the compressed size after 1252 compress() or compress2() on sourceLen bytes. It would be used before a 1253 compress() or compress2() call to allocate the destination buffer. 1254 */ 1255 1256 Z_EXTERN Z_EXPORT 1257 int32_t zng_uncompress(uint8_t *dest, size_t *destLen, const uint8_t *source, size_t sourceLen); 1258 /* 1259 Decompresses the source buffer into the destination buffer. sourceLen is 1260 the byte length of the source buffer. Upon entry, destLen is the total size 1261 of the destination buffer, which must be large enough to hold the entire 1262 uncompressed data. (The size of the uncompressed data must have been saved 1263 previously by the compressor and transmitted to the decompressor by some 1264 mechanism outside the scope of this compression library.) Upon exit, destLen 1265 is the actual size of the uncompressed data. 1266 1267 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1268 enough memory, Z_BUF_ERROR if there was not enough room in the output 1269 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1270 the case where there is not enough room, uncompress() will fill the output 1271 buffer with the uncompressed data up to that point. 1272 */ 1273 1274 1275 Z_EXTERN Z_EXPORT 1276 int32_t zng_uncompress2(uint8_t *dest, size_t *destLen, const uint8_t *source, size_t *sourceLen); 1277 /* 1278 Same as uncompress, except that sourceLen is a pointer, where the 1279 length of the source is *sourceLen. On return, *sourceLen is the number of 1280 source bytes consumed. 1281 */ 1282 1283 1284 #ifdef WITH_GZFILEOP 1285 /* gzip file access functions */ 1286 1287 /* 1288 This library supports reading and writing files in gzip (.gz) format with 1289 an interface similar to that of stdio, using the functions that start with 1290 "gz". The gzip format is different from the zlib format. gzip is a gzip 1291 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1292 */ 1293 1294 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1295 1296 Z_EXTERN Z_EXPORT 1297 gzFile zng_gzopen(const char *path, const char *mode); 1298 /* 1299 Open the gzip (.gz) file at path for reading and decompressing, or 1300 compressing and writing. The mode parameter is as in fopen ("rb" or "wb") 1301 but can also include a compression level ("wb9") or a strategy: 'f' for 1302 filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h", 1303 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression 1304 as in "wb9F". (See the description of deflateInit2 for more information 1305 about the strategy parameter.) 'T' will request transparent writing or 1306 appending with no compression and not using the gzip format. 1307 1308 "a" can be used instead of "w" to request that the gzip stream that will 1309 be written be appended to the file. "+" will result in an error, since 1310 reading and writing to the same gzip file is not supported. The addition of 1311 "x" when writing will create the file exclusively, which fails if the file 1312 already exists. On systems that support it, the addition of "e" when 1313 reading or writing will set the flag to close the file on an execve() call. 1314 1315 These functions, as well as gzip, will read and decode a sequence of gzip 1316 streams in a file. The append function of gzopen() can be used to create 1317 such a file. (Also see gzflush() for another way to do this.) When 1318 appending, gzopen does not test whether the file begins with a gzip stream, 1319 nor does it look for the end of the gzip streams to begin appending. gzopen 1320 will simply append a gzip stream to the existing file. 1321 1322 gzopen can be used to read a file which is not in gzip format; in this 1323 case gzread will directly read from the file without decompression. When 1324 reading, this will be detected automatically by looking for the magic two- 1325 byte gzip header. 1326 1327 gzopen returns NULL if the file could not be opened, if there was 1328 insufficient memory to allocate the gzFile state, or if an invalid mode was 1329 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1330 errno can be checked to determine if the reason gzopen failed was that the 1331 file could not be opened. 1332 */ 1333 1334 Z_EXTERN Z_EXPORT 1335 gzFile zng_gzdopen(int fd, const char *mode); 1336 /* 1337 Associate a gzFile with the file descriptor fd. File descriptors are 1338 obtained from calls like open, dup, creat, pipe or fileno (if the file has 1339 been previously opened with fopen). The mode parameter is as in gzopen. 1340 1341 The next call of gzclose on the returned gzFile will also close the file 1342 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1343 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1344 mode);. The duplicated descriptor should be saved to avoid a leak, since 1345 gzdopen does not close fd if it fails. If you are using fileno() to get the 1346 file descriptor from a FILE *, then you will have to use dup() to avoid 1347 double-close()ing the file descriptor. Both gzclose() and fclose() will 1348 close the associated file descriptor, so they need to have different file 1349 descriptors. 1350 1351 gzdopen returns NULL if there was insufficient memory to allocate the 1352 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1353 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1354 used until the next gz* read, write, seek, or close operation, so gzdopen 1355 will not detect if fd is invalid (unless fd is -1). 1356 */ 1357 1358 Z_EXTERN Z_EXPORT 1359 int32_t zng_gzbuffer(gzFile file, uint32_t size); 1360 /* 1361 Set the internal buffer size used by this library's functions for file to 1362 size. The default buffer size is 8192 bytes. This function must be called 1363 after gzopen() or gzdopen(), and before any other calls that read or write 1364 the file. The buffer memory allocation is always deferred to the first read 1365 or write. Three times that size in buffer space is allocated. A larger 1366 buffer size of, for example, 64K or 128K bytes will noticeably increase the 1367 speed of decompression (reading). 1368 1369 The new buffer size also affects the maximum length for gzprintf(). 1370 1371 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1372 too late. 1373 */ 1374 1375 Z_EXTERN Z_EXPORT 1376 int32_t zng_gzsetparams(gzFile file, int32_t level, int32_t strategy); 1377 /* 1378 Dynamically update the compression level and strategy for file. See the 1379 description of deflateInit2 for the meaning of these parameters. Previously 1380 provided data is flushed before applying the parameter changes. 1381 1382 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1383 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1384 or Z_MEM_ERROR if there is a memory allocation error. 1385 */ 1386 1387 Z_EXTERN Z_EXPORT 1388 int32_t zng_gzread(gzFile file, void *buf, uint32_t len); 1389 /* 1390 Read and decompress up to len uncompressed bytes from file into buf. If 1391 the input file is not in gzip format, gzread copies the given number of 1392 bytes into the buffer directly from the file. 1393 1394 After reaching the end of a gzip stream in the input, gzread will continue 1395 to read, looking for another gzip stream. Any number of gzip streams may be 1396 concatenated in the input file, and will all be decompressed by gzread(). 1397 If something other than a gzip stream is encountered after a gzip stream, 1398 that remaining trailing garbage is ignored (and no error is returned). 1399 1400 gzread can be used to read a gzip file that is being concurrently written. 1401 Upon reaching the end of the input, gzread will return with the available 1402 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1403 gzclearerr can be used to clear the end of file indicator in order to permit 1404 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1405 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1406 middle of a gzip stream. Note that gzread does not return -1 in the event 1407 of an incomplete gzip stream. This error is deferred until gzclose(), which 1408 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1409 stream. Alternatively, gzerror can be used before gzclose to detect this 1410 case. 1411 1412 gzread returns the number of uncompressed bytes actually read, less than 1413 len for end of file, or -1 for error. If len is too large to fit in an int, 1414 then nothing is read, -1 is returned, and the error state is set to 1415 Z_STREAM_ERROR. 1416 */ 1417 1418 Z_EXTERN Z_EXPORT 1419 size_t zng_gzfread(void *buf, size_t size, size_t nitems, gzFile file); 1420 /* 1421 Read and decompress up to nitems items of size size from file into buf, 1422 otherwise operating as gzread() does. This duplicates the interface of 1423 stdio's fread(), with size_t request and return types. If the library 1424 defines size_t, then z_size_t is identical to size_t. If not, then z_size_t 1425 is an unsigned integer type that can contain a pointer. 1426 1427 gzfread() returns the number of full items read of size size, or zero if 1428 the end of the file was reached and a full item could not be read, or if 1429 there was an error. gzerror() must be consulted if zero is returned in 1430 order to determine if there was an error. If the multiplication of size and 1431 nitems overflows, i.e. the product does not fit in a size_t, then nothing 1432 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1433 1434 In the event that the end of file is reached and only a partial item is 1435 available at the end, i.e. the remaining uncompressed data length is not a 1436 multiple of size, then the final partial item is nevertheless read into buf 1437 and the end-of-file flag is set. The length of the partial item read is not 1438 provided, but could be inferred from the result of gztell(). This behavior 1439 is the same as the behavior of fread() implementations in common libraries, 1440 but it prevents the direct use of gzfread() to read a concurrently written 1441 file, resetting and retrying on end-of-file, when size is not 1. 1442 */ 1443 1444 Z_EXTERN Z_EXPORT 1445 int32_t zng_gzwrite(gzFile file, void const *buf, uint32_t len); 1446 /* 1447 Compress and write the len uncompressed bytes at buf to file. gzwrite 1448 returns the number of uncompressed bytes written or 0 in case of error. 1449 */ 1450 1451 Z_EXTERN Z_EXPORT 1452 size_t zng_gzfwrite(void const *buf, size_t size, size_t nitems, gzFile file); 1453 /* 1454 Compress and write nitems items of size size from buf to file, duplicating 1455 the interface of stdio's fwrite(), with size_t request and return types. 1456 1457 gzfwrite() returns the number of full items written of size size, or zero 1458 if there was an error. If the multiplication of size and nitems overflows, 1459 i.e. the product does not fit in a size_t, then nothing is written, zero 1460 is returned, and the error state is set to Z_STREAM_ERROR. 1461 */ 1462 1463 Z_EXTERN Z_EXPORTVA 1464 int32_t zng_gzprintf(gzFile file, const char *format, ...); 1465 /* 1466 Convert, format, compress, and write the arguments (...) to file under 1467 control of the string format, as in fprintf. gzprintf returns the number of 1468 uncompressed bytes actually written, or a negative zlib error code in case 1469 of error. The number of uncompressed bytes written is limited to 8191, or 1470 one less than the buffer size given to gzbuffer(). The caller should assure 1471 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1472 return an error (0) with nothing written. In this case, there may also be a 1473 buffer overflow with unpredictable consequences, which is possible only if 1474 zlib was compiled with the insecure functions sprintf() or vsprintf(), 1475 because the secure snprintf() or vsnprintf() functions were not available. 1476 This can be determined using zlibCompileFlags(). 1477 */ 1478 1479 Z_EXTERN Z_EXPORT 1480 int32_t zng_gzputs(gzFile file, const char *s); 1481 /* 1482 Compress and write the given null-terminated string s to file, excluding 1483 the terminating null character. 1484 1485 gzputs returns the number of characters written, or -1 in case of error. 1486 */ 1487 1488 Z_EXTERN Z_EXPORT 1489 char * zng_gzgets(gzFile file, char *buf, int32_t len); 1490 /* 1491 Read and decompress bytes from file into buf, until len-1 characters are 1492 read, or until a newline character is read and transferred to buf, or an 1493 end-of-file condition is encountered. If any characters are read or if len 1494 is one, the string is terminated with a null character. If no characters 1495 are read due to an end-of-file or len is less than one, then the buffer is 1496 left untouched. 1497 1498 gzgets returns buf which is a null-terminated string, or it returns NULL 1499 for end-of-file or in case of error. If there was an error, the contents at 1500 buf are indeterminate. 1501 */ 1502 1503 Z_EXTERN Z_EXPORT 1504 int32_t zng_gzputc(gzFile file, int32_t c); 1505 /* 1506 Compress and write c, converted to an unsigned char, into file. gzputc 1507 returns the value that was written, or -1 in case of error. 1508 */ 1509 1510 Z_EXTERN Z_EXPORT 1511 int32_t zng_gzgetc(gzFile file); 1512 /* 1513 Read and decompress one byte from file. gzgetc returns this byte or -1 1514 in case of end of file or error. This is implemented as a macro for speed. 1515 As such, it does not do all of the checking the other functions do. I.e. 1516 it does not check to see if file is NULL, nor whether the structure file 1517 points to has been clobbered or not. 1518 */ 1519 1520 Z_EXTERN Z_EXPORT 1521 int32_t zng_gzungetc(int32_t c, gzFile file); 1522 /* 1523 Push c back onto the stream for file to be read as the first character on 1524 the next read. At least one character of push-back is always allowed. 1525 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1526 fail if c is -1, and may fail if a character has been pushed but not read 1527 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1528 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1529 The pushed character will be discarded if the stream is repositioned with 1530 gzseek() or gzrewind(). 1531 */ 1532 1533 Z_EXTERN Z_EXPORT 1534 int32_t zng_gzflush(gzFile file, int32_t flush); 1535 /* 1536 Flush all pending output to file. The parameter flush is as in the 1537 deflate() function. The return value is the zlib error number (see function 1538 gzerror below). gzflush is only permitted when writing. 1539 1540 If the flush parameter is Z_FINISH, the remaining data is written and the 1541 gzip stream is completed in the output. If gzwrite() is called again, a new 1542 gzip stream will be started in the output. gzread() is able to read such 1543 concatenated gzip streams. 1544 1545 gzflush should be called only when strictly necessary because it will 1546 degrade compression if called too often. 1547 */ 1548 1549 Z_EXTERN Z_EXPORT 1550 z_off64_t zng_gzseek(gzFile file, z_off64_t offset, int whence); 1551 /* 1552 Set the starting position to offset relative to whence for the next gzread 1553 or gzwrite on file. The offset represents a number of bytes in the 1554 uncompressed data stream. The whence parameter is defined as in lseek(2); 1555 the value SEEK_END is not supported. 1556 1557 If the file is opened for reading, this function is emulated but can be 1558 extremely slow. If the file is opened for writing, only forward seeks are 1559 supported; gzseek then compresses a sequence of zeroes up to the new 1560 starting position. 1561 1562 gzseek returns the resulting offset location as measured in bytes from 1563 the beginning of the uncompressed stream, or -1 in case of error, in 1564 particular if the file is opened for writing and the new starting position 1565 would be before the current position. 1566 */ 1567 1568 Z_EXTERN Z_EXPORT 1569 int32_t zng_gzrewind(gzFile file); 1570 /* 1571 Rewind file. This function is supported only for reading. 1572 1573 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET). 1574 */ 1575 1576 Z_EXTERN Z_EXPORT 1577 z_off64_t zng_gztell(gzFile file); 1578 /* 1579 Return the starting position for the next gzread or gzwrite on file. 1580 This position represents a number of bytes in the uncompressed data stream, 1581 and is zero when starting, even if appending or reading a gzip stream from 1582 the middle of a file using gzdopen(). 1583 1584 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1585 */ 1586 1587 Z_EXTERN Z_EXPORT 1588 z_off64_t zng_gzoffset(gzFile file); 1589 /* 1590 Return the current compressed (actual) read or write offset of file. This 1591 offset includes the count of bytes that precede the gzip stream, for example 1592 when appending or when using gzdopen() for reading. When reading, the 1593 offset does not include as yet unused buffered input. This information can 1594 be used for a progress indicator. On error, gzoffset() returns -1. 1595 */ 1596 1597 Z_EXTERN Z_EXPORT 1598 int32_t zng_gzeof(gzFile file); 1599 /* 1600 Return true (1) if the end-of-file indicator for file has been set while 1601 reading, false (0) otherwise. Note that the end-of-file indicator is set 1602 only if the read tried to go past the end of the input, but came up short. 1603 Therefore, just like feof(), gzeof() may return false even if there is no 1604 more data to read, in the event that the last read request was for the exact 1605 number of bytes remaining in the input file. This will happen if the input 1606 file size is an exact multiple of the buffer size. 1607 1608 If gzeof() returns true, then the read functions will return no more data, 1609 unless the end-of-file indicator is reset by gzclearerr() and the input file 1610 has grown since the previous end of file was detected. 1611 */ 1612 1613 Z_EXTERN Z_EXPORT 1614 int32_t zng_gzdirect(gzFile file); 1615 /* 1616 Return true (1) if file is being copied directly while reading, or false 1617 (0) if file is a gzip stream being decompressed. 1618 1619 If the input file is empty, gzdirect() will return true, since the input 1620 does not contain a gzip stream. 1621 1622 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1623 cause buffers to be allocated to allow reading the file to determine if it 1624 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1625 gzdirect(). 1626 1627 When writing, gzdirect() returns true (1) if transparent writing was 1628 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1629 gzdirect() is not needed when writing. Transparent writing must be 1630 explicitly requested, so the application already knows the answer. When 1631 linking statically, using gzdirect() will include all of the zlib code for 1632 gzip file reading and decompression, which may not be desired.) 1633 */ 1634 1635 Z_EXTERN Z_EXPORT 1636 int32_t zng_gzclose(gzFile file); 1637 /* 1638 Flush all pending output for file, if necessary, close file and 1639 deallocate the (de)compression state. Note that once file is closed, you 1640 cannot call gzerror with file, since its structures have been deallocated. 1641 gzclose must not be called more than once on the same file, just as free 1642 must not be called more than once on the same allocation. 1643 1644 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1645 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1646 last read ended in the middle of a gzip stream, or Z_OK on success. 1647 */ 1648 1649 Z_EXTERN Z_EXPORT 1650 int32_t zng_gzclose_r(gzFile file); 1651 Z_EXTERN Z_EXPORT 1652 int32_t zng_gzclose_w(gzFile file); 1653 /* 1654 Same as gzclose(), but gzclose_r() is only for use when reading, and 1655 gzclose_w() is only for use when writing or appending. The advantage to 1656 using these instead of gzclose() is that they avoid linking in zlib 1657 compression or decompression code that is not used when only reading or only 1658 writing respectively. If gzclose() is used, then both compression and 1659 decompression code will be included the application when linking to a static 1660 zlib library. 1661 */ 1662 1663 Z_EXTERN Z_EXPORT 1664 const char * zng_gzerror(gzFile file, int32_t *errnum); 1665 /* 1666 Return the error message for the last error which occurred on file. 1667 errnum is set to zlib error number. If an error occurred in the file system 1668 and not in the compression library, errnum is set to Z_ERRNO and the 1669 application may consult errno to get the exact error code. 1670 1671 The application must not modify the returned string. Future calls to 1672 this function may invalidate the previously returned string. If file is 1673 closed, then the string previously returned by gzerror will no longer be 1674 available. 1675 1676 gzerror() should be used to distinguish errors from end-of-file for those 1677 functions above that do not distinguish those cases in their return values. 1678 */ 1679 1680 Z_EXTERN Z_EXPORT 1681 void zng_gzclearerr(gzFile file); 1682 /* 1683 Clear the error and end-of-file flags for file. This is analogous to the 1684 clearerr() function in stdio. This is useful for continuing to read a gzip 1685 file that is being written concurrently. 1686 */ 1687 1688 #endif /* WITH_GZFILEOP */ 1689 1690 /* checksum functions */ 1691 1692 /* 1693 These functions are not related to compression but are exported 1694 anyway because they might be useful in applications using the compression 1695 library. 1696 */ 1697 1698 Z_EXTERN Z_EXPORT 1699 uint32_t zng_adler32(uint32_t adler, const uint8_t *buf, uint32_t len); 1700 /* 1701 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1702 return the updated checksum. An Adler-32 value is in the range of a 32-bit 1703 unsigned integer. If buf is Z_NULL, this function returns the required 1704 initial value for the checksum. 1705 1706 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1707 much faster. 1708 1709 Usage example: 1710 1711 uint32_t adler = adler32(0L, NULL, 0); 1712 1713 while (read_buffer(buffer, length) != EOF) { 1714 adler = adler32(adler, buffer, length); 1715 } 1716 if (adler != original_adler) error(); 1717 */ 1718 1719 Z_EXTERN Z_EXPORT 1720 uint32_t zng_adler32_z(uint32_t adler, const uint8_t *buf, size_t len); 1721 /* 1722 Same as adler32(), but with a size_t length. 1723 */ 1724 1725 Z_EXTERN Z_EXPORT 1726 uint32_t zng_adler32_combine(uint32_t adler1, uint32_t adler2, z_off64_t len2); 1727 /* 1728 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1729 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1730 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1731 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1732 that the z_off_t type (like off_t) is a signed integer. If len2 is 1733 negative, the result has no meaning or utility. 1734 */ 1735 1736 Z_EXTERN Z_EXPORT 1737 uint32_t zng_crc32(uint32_t crc, const uint8_t *buf, uint32_t len); 1738 /* 1739 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1740 updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer. 1741 If buf is Z_NULL, this function returns the required initial value for the 1742 crc. Pre- and post-conditioning (one's complement) is performed within this 1743 function so it shouldn't be done by the application. 1744 1745 Usage example: 1746 1747 uint32_t crc = crc32(0L, NULL, 0); 1748 1749 while (read_buffer(buffer, length) != EOF) { 1750 crc = crc32(crc, buffer, length); 1751 } 1752 if (crc != original_crc) error(); 1753 */ 1754 1755 Z_EXTERN Z_EXPORT 1756 uint32_t zng_crc32_z(uint32_t crc, const uint8_t *buf, size_t len); 1757 /* 1758 Same as crc32(), but with a size_t length. 1759 */ 1760 1761 Z_EXTERN Z_EXPORT 1762 uint32_t zng_crc32_combine(uint32_t crc1, uint32_t crc2, z_off64_t len2); 1763 1764 /* 1765 Combine two CRC-32 check values into one. For two sequences of bytes, 1766 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1767 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1768 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1769 len2. 1770 */ 1771 1772 Z_EXTERN Z_EXPORT 1773 void zng_crc32_combine_gen(uint32_t op[32], z_off64_t len2); 1774 1775 /* 1776 Generate the operator op corresponding to length len2, to be used with 1777 crc32_combine_op(). op must have room for 32 uint32_t values. (32 is the 1778 number of bits in the CRC.) 1779 */ 1780 1781 Z_EXTERN Z_EXPORT 1782 uint32_t zng_crc32_combine_op(uint32_t crc1, uint32_t crc2, const uint32_t *op); 1783 /* 1784 Give the same result as crc32_combine(), using op in place of len2. op is 1785 is generated from len2 by crc32_combine_gen(). This will be faster than 1786 crc32_combine() if the generated op is used many times. 1787 */ 1788 1789 /* various hacks, don't look :) */ 1790 1791 /* zng_deflateInit and zng_inflateInit are macros to allow checking the zlib version 1792 * and the compiler's view of zng_stream: 1793 */ 1794 Z_EXTERN Z_EXPORT int32_t zng_deflateInit_(zng_stream *strm, int32_t level, const char *version, int32_t stream_size); 1795 Z_EXTERN Z_EXPORT int32_t zng_inflateInit_(zng_stream *strm, const char *version, int32_t stream_size); 1796 Z_EXTERN Z_EXPORT int32_t zng_deflateInit2_(zng_stream *strm, int32_t level, int32_t method, int32_t windowBits, int32_t memLevel, 1797 int32_t strategy, const char *version, int32_t stream_size); 1798 Z_EXTERN Z_EXPORT int32_t zng_inflateInit2_(zng_stream *strm, int32_t windowBits, const char *version, int32_t stream_size); 1799 Z_EXTERN Z_EXPORT int32_t zng_inflateBackInit_(zng_stream *strm, int32_t windowBits, uint8_t *window, 1800 const char *version, int32_t stream_size); 1801 1802 #define zng_deflateInit(strm, level) zng_deflateInit_((strm), (level), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1803 #define zng_inflateInit(strm) zng_inflateInit_((strm), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1804 #define zng_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1805 zng_deflateInit2_((strm), (level), (method), (windowBits), (memLevel), \ 1806 (strategy), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1807 #define zng_inflateInit2(strm, windowBits) zng_inflateInit2_((strm), (windowBits), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1808 #define zng_inflateBackInit(strm, windowBits, window) \ 1809 zng_inflateBackInit_((strm), (windowBits), (window), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1810 1811 #ifdef WITH_GZFILEOP 1812 1813 /* gzgetc() macro and its supporting function and exposed data structure. Note 1814 * that the real internal state is much larger than the exposed structure. 1815 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1816 * user should not mess with these exposed elements, since their names or 1817 * behavior could change in the future, perhaps even capriciously. They can 1818 * only be used by the gzgetc() macro. You have been warned. 1819 */ 1820 struct gzFile_s { 1821 unsigned have; 1822 unsigned char *next; 1823 z_off64_t pos; 1824 }; 1825 Z_EXTERN Z_EXPORT int32_t zng_gzgetc_(gzFile file); /* backward compatibility */ 1826 # define zng_gzgetc(g) ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (zng_gzgetc)(g)) 1827 1828 #endif /* WITH_GZFILEOP */ 1829 1830 1831 typedef enum { 1832 Z_DEFLATE_LEVEL = 0, /* compression level, represented as an int */ 1833 Z_DEFLATE_STRATEGY = 1, /* compression strategy, represented as an int */ 1834 Z_DEFLATE_REPRODUCIBLE = 2, 1835 /* 1836 Whether reproducible compression results are required. Represented as an int, where 0 means that it is allowed 1837 to trade reproducibility for e.g. improved performance or compression ratio, and non-0 means that 1838 reproducibility is strictly required. Reproducibility is guaranteed only when using an identical zlib-ng build. 1839 Default is 0. 1840 */ 1841 } zng_deflate_param; 1842 1843 typedef struct { 1844 zng_deflate_param param; /* parameter ID */ 1845 void *buf; /* parameter value */ 1846 size_t size; /* parameter value size */ 1847 int32_t status; /* result of the last set/get call */ 1848 } zng_deflate_param_value; 1849 1850 Z_EXTERN Z_EXPORT 1851 int32_t zng_deflateSetParams(zng_stream *strm, zng_deflate_param_value *params, size_t count); 1852 /* 1853 Sets the values of the given zlib-ng deflate stream parameters. All the buffers are copied internally, so the 1854 caller still owns them after this function returns. Returns Z_OK if success. 1855 1856 If the size of at least one of the buffers is too small to hold the entire value of the corresponding parameter, 1857 or if the same parameter is specified multiple times, Z_BUF_ERROR is returned. The caller may inspect status fields 1858 in order to determine which of the parameters caused this error. No other changes are performed. 1859 1860 If the stream state is inconsistent or if at least one of the values cannot be updated, Z_STREAM_ERROR is 1861 returned. The caller may inspect status fields in order to determine which of the parameters caused this error. 1862 Parameters, whose status field is equal to Z_OK, have been applied successfully. If all status fields are not equal 1863 to Z_STREAM_ERROR, then the error was caused by a stream state inconsistency. 1864 1865 If there are no other errors, but at least one parameter is not supported by the current zlib-ng version, 1866 Z_VERSION_ERROR is returned. The caller may inspect status fields in order to determine which of the parameters 1867 caused this error. 1868 */ 1869 1870 Z_EXTERN Z_EXPORT 1871 int32_t zng_deflateGetParams(zng_stream *strm, zng_deflate_param_value *params, size_t count); 1872 /* 1873 Copies the values of the given zlib-ng deflate stream parameters into the user-provided buffers. Returns Z_OK if 1874 success, Z_VERSION_ERROR if at least one parameter is not supported by the current zlib-ng version, Z_STREAM_ERROR 1875 if the stream state is inconsistent, and Z_BUF_ERROR if the size of at least one buffer is too small to hold the 1876 entire value of the corresponding parameter. 1877 */ 1878 1879 /* undocumented functions */ 1880 Z_EXTERN Z_EXPORT const char * zng_zError (int32_t); 1881 Z_EXTERN Z_EXPORT int32_t zng_inflateSyncPoint (zng_stream *); 1882 Z_EXTERN Z_EXPORT const uint32_t * zng_get_crc_table (void); 1883 Z_EXTERN Z_EXPORT int32_t zng_inflateUndermine (zng_stream *, int32_t); 1884 Z_EXTERN Z_EXPORT int32_t zng_inflateValidate (zng_stream *, int32_t); 1885 Z_EXTERN Z_EXPORT unsigned long zng_inflateCodesUsed (zng_stream *); 1886 Z_EXTERN Z_EXPORT int32_t zng_inflateResetKeep (zng_stream *); 1887 Z_EXTERN Z_EXPORT int32_t zng_deflateResetKeep (zng_stream *); 1888 1889 #ifdef WITH_GZFILEOP 1890 # if defined(_WIN32) 1891 Z_EXTERN Z_EXPORT gzFile zng_gzopen_w(const wchar_t *path, const char *mode); 1892 # endif 1893 Z_EXTERN Z_EXPORTVA int32_t zng_gzvprintf(gzFile file, const char *format, va_list va); 1894 #endif 1895 1896 #ifdef __cplusplus 1897 } 1898 #endif 1899 1900 #endif /* ZNGLIB_H_ */ 1901