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 http://tools.ietf.org/html/rfc1950 29 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 30 */ 31 32 #include <stdint.h> 33 #include "zconf-ng.h" 34 35 #ifdef __cplusplus 36 extern "C" { 37 #endif 38 39 #define ZLIBNG_VERSION "1.9.9" 40 #define ZLIBNG_VERNUM 0x1990 41 #define ZLIBNG_VER_MAJOR 1 42 #define ZLIBNG_VER_MINOR 9 43 #define ZLIBNG_VER_REVISION 9 44 #define ZLIBNG_VER_SUBREVISION 0 45 46 /* 47 The 'zlib' compression library provides in-memory compression and 48 decompression functions, including integrity checks of the uncompressed data. 49 This version of the library supports only one compression method (deflation) 50 but other algorithms will be added later and will have the same stream 51 interface. 52 53 Compression can be done in a single step if the buffers are large enough, 54 or can be done by repeated calls of the compression function. In the latter 55 case, the application must provide more input and/or consume the output 56 (providing more output space) before each call. 57 58 The compressed data format used by default by the in-memory functions is 59 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 60 around a deflate stream, which is itself documented in RFC 1951. 61 62 The library also supports reading and writing files in gzip (.gz) format 63 with an interface similar to that of stdio using the functions that start 64 with "gz". The gzip format is different from the zlib format. gzip is a 65 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 66 67 This library can optionally read and write gzip and raw deflate streams in 68 memory as well. 69 70 The zlib format was designed to be compact and fast for use in memory 71 and on communications channels. The gzip format was designed for single- 72 file compression on file systems, has a larger header than zlib to maintain 73 directory information, and uses a different, slower check method than zlib. 74 75 The library does not install any signal handler. The decoder checks 76 the consistency of the compressed data, so the library should never crash 77 even in the case of corrupted input. 78 */ 79 80 typedef void *(*alloc_func) (void *opaque, unsigned int items, unsigned int size); 81 typedef void (*free_func) (void *opaque, void *address); 82 83 struct internal_state; 84 85 typedef struct zng_stream_s { 86 const uint8_t *next_in; /* next input byte */ 87 uint32_t avail_in; /* number of bytes available at next_in */ 88 size_t total_in; /* total number of input bytes read so far */ 89 90 uint8_t *next_out; /* next output byte will go here */ 91 uint32_t avail_out; /* remaining free space at next_out */ 92 size_t total_out; /* total number of bytes output so far */ 93 94 const char *msg; /* last error message, NULL if no error */ 95 struct internal_state *state; /* not visible by applications */ 96 97 alloc_func zalloc; /* used to allocate the internal state */ 98 free_func zfree; /* used to free the internal state */ 99 void *opaque; /* private data object passed to zalloc and zfree */ 100 101 int data_type; /* best guess about the data type: binary or text 102 for deflate, or the decoding state for inflate */ 103 uint32_t adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 104 unsigned long reserved; /* reserved for future use */ 105 } zng_stream; 106 107 typedef zng_stream *zng_streamp; /* Obsolete type, retained for compatibility only */ 108 109 /* 110 gzip header information passed to and from zlib routines. See RFC 1952 111 for more details on the meanings of these fields. 112 */ 113 typedef struct zng_gz_header_s { 114 int32_t text; /* true if compressed data believed to be text */ 115 unsigned long time; /* modification time */ 116 int32_t xflags; /* extra flags (not used when writing a gzip file) */ 117 int32_t os; /* operating system */ 118 uint8_t *extra; /* pointer to extra field or NULL if none */ 119 uint32_t extra_len; /* extra field length (valid if extra != NULL) */ 120 uint32_t extra_max; /* space at extra (only when reading header) */ 121 uint8_t *name; /* pointer to zero-terminated file name or NULL */ 122 uint32_t name_max; /* space at name (only when reading header) */ 123 uint8_t *comment; /* pointer to zero-terminated comment or NULL */ 124 uint32_t comm_max; /* space at comment (only when reading header) */ 125 int32_t hcrc; /* true if there was or will be a header crc */ 126 int32_t done; /* true when done reading gzip header (not used when writing a gzip file) */ 127 } zng_gz_header; 128 129 typedef zng_gz_header *zng_gz_headerp; 130 131 /* 132 The application must update next_in and avail_in when avail_in has dropped 133 to zero. It must update next_out and avail_out when avail_out has dropped 134 to zero. The application must initialize zalloc, zfree and opaque before 135 calling the init function. All other fields are set by the compression 136 library and must not be updated by the application. 137 138 The opaque value provided by the application will be passed as the first 139 parameter for calls of zalloc and zfree. This can be useful for custom 140 memory management. The compression library attaches no meaning to the 141 opaque value. 142 143 zalloc must return NULL if there is not enough memory for the object. 144 If zlib is used in a multi-threaded application, zalloc and zfree must be 145 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 146 Z_NULL on entry to the initialization function, they are set to internal 147 routines that use the standard library functions malloc() and free(). 148 149 The fields total_in and total_out can be used for statistics or progress 150 reports. After compression, total_in holds the total size of the 151 uncompressed data and may be saved for use by the decompressor (particularly 152 if the decompressor wants to decompress everything in a single step). 153 */ 154 155 /* constants */ 156 157 #define Z_NO_FLUSH 0 158 #define Z_PARTIAL_FLUSH 1 159 #define Z_SYNC_FLUSH 2 160 #define Z_FULL_FLUSH 3 161 #define Z_FINISH 4 162 #define Z_BLOCK 5 163 #define Z_TREES 6 164 /* Allowed flush values; see deflate() and inflate() below for details */ 165 166 #define Z_OK 0 167 #define Z_STREAM_END 1 168 #define Z_NEED_DICT 2 169 #define Z_ERRNO (-1) 170 #define Z_STREAM_ERROR (-2) 171 #define Z_DATA_ERROR (-3) 172 #define Z_MEM_ERROR (-4) 173 #define Z_BUF_ERROR (-5) 174 #define Z_VERSION_ERROR (-6) 175 /* Return codes for the compression/decompression functions. Negative values 176 * are errors, positive values are used for special but normal events. 177 */ 178 179 #define Z_NO_COMPRESSION 0 180 #define Z_BEST_SPEED 1 181 #define Z_BEST_COMPRESSION 9 182 #define Z_DEFAULT_COMPRESSION (-1) 183 /* compression levels */ 184 185 #define Z_FILTERED 1 186 #define Z_HUFFMAN_ONLY 2 187 #define Z_RLE 3 188 #define Z_FIXED 4 189 #define Z_DEFAULT_STRATEGY 0 190 /* compression strategy; see deflateInit2() below for details */ 191 192 #define Z_BINARY 0 193 #define Z_TEXT 1 194 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 195 #define Z_UNKNOWN 2 196 /* Possible values of the data_type field for deflate() */ 197 198 #define Z_DEFLATED 8 199 /* The deflate compression method (the only one supported in this version) */ 200 201 #define Z_NULL NULL /* for compatibility with zlib, was for initializing zalloc, zfree, opaque */ 202 203 204 /* basic functions */ 205 206 Z_EXTERN Z_EXPORT 207 const char *zlibng_version(void); 208 /* The application can compare zlibng_version and ZLIBNG_VERSION for consistency. 209 If the first character differs, the library code actually used is not 210 compatible with the zlib-ng.h header file used by the application. This check 211 is automatically made by deflateInit and inflateInit. 212 */ 213 214 /* 215 Z_EXTERN Z_EXPORT 216 int zng_deflateInit(zng_stream *strm, int level); 217 218 Initializes the internal stream state for compression. The fields 219 zalloc, zfree and opaque must be initialized before by the caller. If 220 zalloc and zfree are set to NULL, deflateInit updates them to use default 221 allocation functions. 222 223 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 224 1 gives best speed, 9 gives best compression, 0 gives no compression at all 225 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 226 requests a default compromise between speed and compression (currently 227 equivalent to level 6). 228 229 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 230 memory, Z_STREAM_ERROR if level is not a valid compression level, or 231 Z_VERSION_ERROR if the zlib library version (zng_version) is incompatible 232 with the version assumed by the caller (ZLIBNG_VERSION). msg is set to null 233 if there is no error message. deflateInit does not perform any compression: 234 this will be done by deflate(). 235 */ 236 237 238 Z_EXTERN Z_EXPORT 239 int32_t zng_deflate(zng_stream *strm, int32_t flush); 240 /* 241 deflate compresses as much data as possible, and stops when the input 242 buffer becomes empty or the output buffer becomes full. It may introduce 243 some output latency (reading input without producing any output) except when 244 forced to flush. 245 246 The detailed semantics are as follows. deflate performs one or both of the 247 following actions: 248 249 - Compress more input starting at next_in and update next_in and avail_in 250 accordingly. If not all input can be processed (because there is not 251 enough room in the output buffer), next_in and avail_in are updated and 252 processing will resume at this point for the next call of deflate(). 253 254 - Generate more output starting at next_out and update next_out and avail_out 255 accordingly. This action is forced if the parameter flush is non zero. 256 Forcing flush frequently degrades the compression ratio, so this parameter 257 should be set only when necessary. Some output may be provided even if 258 flush is zero. 259 260 Before the call of deflate(), the application should ensure that at least 261 one of the actions is possible, by providing more input and/or consuming more 262 output, and updating avail_in or avail_out accordingly; avail_out should 263 never be zero before the call. The application can consume the compressed 264 output when it wants, for example when the output buffer is full (avail_out 265 == 0), or after each call of deflate(). If deflate returns Z_OK and with 266 zero avail_out, it must be called again after making room in the output 267 buffer because there might be more output pending. See deflatePending(), 268 which can be used if desired to determine whether or not there is more ouput 269 in that case. 270 271 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 272 decide how much data to accumulate before producing output, in order to 273 maximize compression. 274 275 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 276 flushed to the output buffer and the output is aligned on a byte boundary, so 277 that the decompressor can get all input data available so far. (In 278 particular avail_in is zero after the call if enough output space has been 279 provided before the call.) Flushing may degrade compression for some 280 compression algorithms and so it should be used only when necessary. This 281 completes the current deflate block and follows it with an empty stored block 282 that is three bits plus filler bits to the next byte, followed by four bytes 283 (00 00 ff ff). 284 285 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 286 output buffer, but the output is not aligned to a byte boundary. All of the 287 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 288 This completes the current deflate block and follows it with an empty fixed 289 codes block that is 10 bits long. This assures that enough bytes are output 290 in order for the decompressor to finish the block before the empty fixed 291 codes block. 292 293 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 294 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 295 seven bits of the current block are held to be written as the next byte after 296 the next deflate block is completed. In this case, the decompressor may not 297 be provided enough bits at this point in order to complete decompression of 298 the data provided so far to the compressor. It may need to wait for the next 299 block to be emitted. This is for advanced applications that need to control 300 the emission of deflate blocks. 301 302 If flush is set to Z_FULL_FLUSH, all output is flushed as with 303 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 304 restart from this point if previous compressed data has been damaged or if 305 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 306 compression. 307 308 If deflate returns with avail_out == 0, this function must be called again 309 with the same value of the flush parameter and more output space (updated 310 avail_out), until the flush is complete (deflate returns with non-zero 311 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 312 avail_out is greater than six to avoid repeated flush markers due to 313 avail_out == 0 on return. 314 315 If the parameter flush is set to Z_FINISH, pending input is processed, 316 pending output is flushed and deflate returns with Z_STREAM_END if there was 317 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 318 function must be called again with Z_FINISH and more output space (updated 319 avail_out) but no more input data, until it returns with Z_STREAM_END or an 320 error. After deflate has returned Z_STREAM_END, the only possible operations 321 on the stream are deflateReset or deflateEnd. 322 323 Z_FINISH can be used in the first deflate call after deflateInit if all the 324 compression is to be done in a single step. In order to complete in one 325 call, avail_out must be at least the value returned by deflateBound (see 326 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 327 output space is provided, deflate will not return Z_STREAM_END, and it must 328 be called again as described above. 329 330 deflate() sets strm->adler to the Adler-32 checksum of all input read 331 so far (that is, total_in bytes). If a gzip stream is being generated, then 332 strm->adler will be the CRC-32 checksum of the input read so far. (See 333 deflateInit2 below.) 334 335 deflate() may update strm->data_type if it can make a good guess about 336 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 337 considered binary. This field is only for information purposes and does not 338 affect the compression algorithm in any manner. 339 340 deflate() returns Z_OK if some progress has been made (more input 341 processed or more output produced), Z_STREAM_END if all input has been 342 consumed and all output has been produced (only when flush is set to 343 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 344 if next_in or next_out was NULL) or the state was inadvertently written over 345 by the application), or Z_BUF_ERROR if no progress is possible (for example 346 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 347 deflate() can be called again with more input and more output space to 348 continue compressing. 349 */ 350 351 352 Z_EXTERN Z_EXPORT 353 int32_t zng_deflateEnd(zng_stream *strm); 354 /* 355 All dynamically allocated data structures for this stream are freed. 356 This function discards any unprocessed input and does not flush any pending 357 output. 358 359 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 360 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 361 prematurely (some input or output was discarded). In the error case, msg 362 may be set but then points to a static string (which must not be 363 deallocated). 364 */ 365 366 367 /* 368 Z_EXTERN Z_EXPORT 369 int zng_inflateInit(zng_stream *strm); 370 371 Initializes the internal stream state for decompression. The fields 372 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 373 the caller. In the current version of inflate, the provided input is not 374 read or consumed. The allocation of a sliding window will be deferred to 375 the first call of inflate (if the decompression does not complete on the 376 first call). If zalloc and zfree are set to NULL, inflateInit updates 377 them to use default allocation functions. 378 379 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 380 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 381 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 382 invalid, such as a null pointer to the structure. msg is set to null if 383 there is no error message. inflateInit does not perform any decompression. 384 Actual decompression will be done by inflate(). So next_in, and avail_in, 385 next_out, and avail_out are unused and unchanged. The current 386 implementation of inflateInit() does not process any header information -- 387 that is deferred until inflate() is called. 388 */ 389 390 391 Z_EXTERN Z_EXPORT 392 int32_t zng_inflate(zng_stream *strm, int32_t flush); 393 /* 394 inflate decompresses as much data as possible, and stops when the input 395 buffer becomes empty or the output buffer becomes full. It may introduce 396 some output latency (reading input without producing any output) except when 397 forced to flush. 398 399 The detailed semantics are as follows. inflate performs one or both of the 400 following actions: 401 402 - Decompress more input starting at next_in and update next_in and avail_in 403 accordingly. If not all input can be processed (because there is not 404 enough room in the output buffer), then next_in and avail_in are updated 405 accordingly, and processing will resume at this point for the next call of 406 inflate(). 407 408 - Generate more output starting at next_out and update next_out and avail_out 409 accordingly. inflate() provides as much output as possible, until there is 410 no more input data or no more space in the output buffer (see below about 411 the flush parameter). 412 413 Before the call of inflate(), the application should ensure that at least 414 one of the actions is possible, by providing more input and/or consuming more 415 output, and updating the next_* and avail_* values accordingly. If the 416 caller of inflate() does not provide both available input and available 417 output space, it is possible that there will be no progress made. The 418 application can consume the uncompressed output when it wants, for example 419 when the output buffer is full (avail_out == 0), or after each call of 420 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 421 called again after making room in the output buffer because there might be 422 more output pending. 423 424 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 425 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 426 output as possible to the output buffer. Z_BLOCK requests that inflate() 427 stop if and when it gets to the next deflate block boundary. When decoding 428 the zlib or gzip format, this will cause inflate() to return immediately 429 after the header and before the first block. When doing a raw inflate, 430 inflate() will go ahead and process the first block, and will return when it 431 gets to the end of that block, or when it runs out of data. 432 433 The Z_BLOCK option assists in appending to or combining deflate streams. 434 To assist in this, on return inflate() always sets strm->data_type to the 435 number of unused bits in the last byte taken from strm->next_in, plus 64 if 436 inflate() is currently decoding the last block in the deflate stream, plus 437 128 if inflate() returned immediately after decoding an end-of-block code or 438 decoding the complete header up to just before the first byte of the deflate 439 stream. The end-of-block will not be indicated until all of the uncompressed 440 data from that block has been written to strm->next_out. The number of 441 unused bits may in general be greater than seven, except when bit 7 of 442 data_type is set, in which case the number of unused bits will be less than 443 eight. data_type is set as noted here every time inflate() returns for all 444 flush options, and so can be used to determine the amount of currently 445 consumed input in bits. 446 447 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 448 end of each deflate block header is reached, before any actual data in that 449 block is decoded. This allows the caller to determine the length of the 450 deflate block header for later use in random access within a deflate block. 451 256 is added to the value of strm->data_type when inflate() returns 452 immediately after reaching the end of the deflate block header. 453 454 inflate() should normally be called until it returns Z_STREAM_END or an 455 error. However if all decompression is to be performed in a single step (a 456 single call of inflate), the parameter flush should be set to Z_FINISH. In 457 this case all pending input is processed and all pending output is flushed; 458 avail_out must be large enough to hold all of the uncompressed data for the 459 operation to complete. (The size of the uncompressed data may have been 460 saved by the compressor for this purpose.) The use of Z_FINISH is not 461 required to perform an inflation in one step. However it may be used to 462 inform inflate that a faster approach can be used for the single inflate() 463 call. Z_FINISH also informs inflate to not maintain a sliding window if the 464 stream completes, which reduces inflate's memory footprint. If the stream 465 does not complete, either because not all of the stream is provided or not 466 enough output space is provided, then a sliding window will be allocated and 467 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 468 been used. 469 470 In this implementation, inflate() always flushes as much output as 471 possible to the output buffer, and always uses the faster approach on the 472 first call. So the effects of the flush parameter in this implementation are 473 on the return value of inflate() as noted below, when inflate() returns early 474 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 475 memory for a sliding window when Z_FINISH is used. 476 477 If a preset dictionary is needed after this call (see inflateSetDictionary 478 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 479 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 480 strm->adler to the Adler-32 checksum of all output produced so far (that is, 481 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 482 below. At the end of the stream, inflate() checks that its computed Adler-32 483 checksum is equal to that saved by the compressor and returns Z_STREAM_END 484 only if the checksum is correct. 485 486 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 487 deflate data. The header type is detected automatically, if requested when 488 initializing with inflateInit2(). Any information contained in the gzip 489 header is not retained unless inflateGetHeader() is used. When processing 490 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 491 produced so far. The CRC-32 is checked against the gzip trailer, as is the 492 uncompressed length, modulo 2^32. 493 494 inflate() returns Z_OK if some progress has been made (more input processed 495 or more output produced), Z_STREAM_END if the end of the compressed data has 496 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 497 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 498 corrupted (input stream not conforming to the zlib format or incorrect check 499 value, in which case strm->msg points to a string with a more specific 500 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 501 next_in or next_out was NULL, or the state was inadvertently written over 502 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 503 if no progress is possible or if there was not enough room in the output 504 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 505 inflate() can be called again with more input and more output space to 506 continue decompressing. If Z_DATA_ERROR is returned, the application may 507 then call inflateSync() to look for a good compression block if a partial 508 recovery of the data is to be attempted. 509 */ 510 511 512 Z_EXTERN Z_EXPORT 513 int32_t zng_inflateEnd(zng_stream *strm); 514 /* 515 All dynamically allocated data structures for this stream are freed. 516 This function discards any unprocessed input and does not flush any pending 517 output. 518 519 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 520 was inconsistent. 521 */ 522 523 524 /* Advanced functions */ 525 526 /* 527 The following functions are needed only in some special applications. 528 */ 529 530 /* 531 Z_EXTERN Z_EXPORT 532 int zng_deflateInit2(zng_stream *strm, int level, int method, int windowBits, int memLevel, int strategy); 533 534 This is another version of deflateInit with more compression options. The 535 fields zalloc, zfree and opaque must be initialized before by the caller. 536 537 The method parameter is the compression method. It must be Z_DEFLATED in 538 this version of the library. 539 540 The windowBits parameter is the base two logarithm of the window size 541 (the size of the history buffer). It should be in the range 8..15 for this 542 version of the library. Larger values of this parameter result in better 543 compression at the expense of memory usage. The default value is 15 if 544 deflateInit is used instead. 545 546 For the current implementation of deflate(), a windowBits value of 8 (a 547 window size of 256 bytes) is not supported. As a result, a request for 8 548 will result in 9 (a 512-byte window). In that case, providing 8 to 549 inflateInit2() will result in an error when the zlib header with 9 is 550 checked against the initialization of inflate(). The remedy is to not use 8 551 with deflateInit2() with this initialization, or at least in that case use 9 552 with inflateInit2(). 553 554 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 555 determines the window size. deflate() will then generate raw deflate data 556 with no zlib header or trailer, and will not compute a check value. 557 558 windowBits can also be greater than 15 for optional gzip encoding. Add 559 16 to windowBits to write a simple gzip header and trailer around the 560 compressed data instead of a zlib wrapper. The gzip header will have no 561 file name, no extra data, no comment, no modification time (set to zero), no 562 header crc, and the operating system will be set to the appropriate value, 563 if the operating system was determined at compile time. If a gzip stream is 564 being written, strm->adler is a CRC-32 instead of an Adler-32. 565 566 For raw deflate or gzip encoding, a request for a 256-byte window is 567 rejected as invalid, since only the zlib header provides a means of 568 transmitting the window size to the decompressor. 569 570 The memLevel parameter specifies how much memory should be allocated 571 for the internal compression state. memLevel=1 uses minimum memory but is 572 slow and reduces compression ratio; memLevel=9 uses maximum memory for 573 optimal speed. The default value is 8. See zconf.h for total memory usage 574 as a function of windowBits and memLevel. 575 576 The strategy parameter is used to tune the compression algorithm. Use the 577 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 578 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 579 string match), or Z_RLE to limit match distances to one (run-length 580 encoding). Filtered data consists mostly of small values with a somewhat 581 random distribution. In this case, the compression algorithm is tuned to 582 compress them better. The effect of Z_FILTERED is to force more Huffman 583 coding and less string matching; it is somewhat intermediate between 584 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 585 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 586 strategy parameter only affects the compression ratio but not the 587 correctness of the compressed output even if it is not set appropriately. 588 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 589 decoder for special applications. 590 591 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 592 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 593 method), or Z_VERSION_ERROR if the zlib library version (zng_version) is 594 incompatible with the version assumed by the caller (ZLIBNG_VERSION). msg is 595 set to null if there is no error message. deflateInit2 does not perform any 596 compression: this will be done by deflate(). 597 */ 598 599 Z_EXTERN Z_EXPORT 600 int32_t zng_deflateSetDictionary(zng_stream *strm, const uint8_t *dictionary, uint32_t dictLength); 601 /* 602 Initializes the compression dictionary from the given byte sequence 603 without producing any compressed output. When using the zlib format, this 604 function must be called immediately after deflateInit, deflateInit2 or 605 deflateReset, and before any call of deflate. When doing raw deflate, this 606 function must be called either before any call of deflate, or immediately 607 after the completion of a deflate block, i.e. after all input has been 608 consumed and all output has been delivered when using any of the flush 609 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 610 compressor and decompressor must use exactly the same dictionary (see 611 inflateSetDictionary). 612 613 The dictionary should consist of strings (byte sequences) that are likely 614 to be encountered later in the data to be compressed, with the most commonly 615 used strings preferably put towards the end of the dictionary. Using a 616 dictionary is most useful when the data to be compressed is short and can be 617 predicted with good accuracy; the data can then be compressed better than 618 with the default empty dictionary. 619 620 Depending on the size of the compression data structures selected by 621 deflateInit or deflateInit2, a part of the dictionary may in effect be 622 discarded, for example if the dictionary is larger than the window size 623 provided in deflateInit or deflateInit2. Thus the strings most likely to be 624 useful should be put at the end of the dictionary, not at the front. In 625 addition, the current implementation of deflate will use at most the window 626 size minus 262 bytes of the provided dictionary. 627 628 Upon return of this function, strm->adler is set to the Adler-32 value 629 of the dictionary; the decompressor may later use this value to determine 630 which dictionary has been used by the compressor. (The Adler-32 value 631 applies to the whole dictionary even if only a subset of the dictionary is 632 actually used by the compressor.) If a raw deflate was requested, then the 633 Adler-32 value is not computed and strm->adler is not set. 634 635 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 636 parameter is invalid (e.g. dictionary being NULL) or the stream state is 637 inconsistent (for example if deflate has already been called for this stream 638 or if not at a block boundary for raw deflate). deflateSetDictionary does 639 not perform any compression: this will be done by deflate(). 640 */ 641 642 Z_EXTERN Z_EXPORT 643 int32_t zng_deflateGetDictionary(zng_stream *strm, uint8_t *dictionary, uint32_t *dictLength); 644 /* 645 Returns the sliding dictionary being maintained by deflate. dictLength is 646 set to the number of bytes in the dictionary, and that many bytes are copied 647 to dictionary. dictionary must have enough space, where 32768 bytes is 648 always enough. If deflateGetDictionary() is called with dictionary equal to 649 Z_NULL, then only the dictionary length is returned, and nothing is copied. 650 Similary, if dictLength is Z_NULL, then it is not set. 651 652 deflateGetDictionary() may return a length less than the window size, even 653 when more than the window size in input has been provided. It may return up 654 to 258 bytes less in that case, due to how zlib's implementation of deflate 655 manages the sliding window and lookahead for matches, where matches can be 656 up to 258 bytes long. If the application needs the last window-size bytes of 657 input, then that would need to be saved by the application outside of zlib. 658 659 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 660 stream state is inconsistent. 661 */ 662 663 Z_EXTERN Z_EXPORT 664 int32_t zng_deflateCopy(zng_stream *dest, zng_stream *source); 665 /* 666 Sets the destination stream as a complete copy of the source stream. 667 668 This function can be useful when several compression strategies will be 669 tried, for example when there are several ways of pre-processing the input 670 data with a filter. The streams that will be discarded should then be freed 671 by calling deflateEnd. Note that deflateCopy duplicates the internal 672 compression state which can be quite large, so this strategy is slow and can 673 consume lots of memory. 674 675 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 676 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 677 (such as zalloc being NULL). msg is left unchanged in both source and 678 destination. 679 */ 680 681 Z_EXTERN Z_EXPORT 682 int32_t zng_deflateReset(zng_stream *strm); 683 /* 684 This function is equivalent to deflateEnd followed by deflateInit, but 685 does not free and reallocate the internal compression state. The stream 686 will leave the compression level and any other attributes that may have been 687 set unchanged. 688 689 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 690 stream state was inconsistent (such as zalloc or state being NULL). 691 */ 692 693 Z_EXTERN Z_EXPORT 694 int32_t zng_deflateParams(zng_stream *strm, int32_t level, int32_t strategy); 695 /* 696 Dynamically update the compression level and compression strategy. The 697 interpretation of level and strategy is as in deflateInit2(). This can be 698 used to switch between compression and straight copy of the input data, or 699 to switch to a different kind of input data requiring a different strategy. 700 If the compression approach (which is a function of the level) or the 701 strategy is changed, and if there have been any deflate() calls since the 702 state was initialized or reset, then the input available so far is 703 compressed with the old level and strategy using deflate(strm, Z_BLOCK). 704 There are three approaches for the compression levels 0, 1..3, and 4..9 705 respectively. The new level and strategy will take effect at the next call 706 of deflate(). 707 708 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 709 not have enough output space to complete, then the parameter change will not 710 take effect. In this case, deflateParams() can be called again with the 711 same parameters and more output space to try again. 712 713 In order to assure a change in the parameters on the first try, the 714 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 715 request until strm.avail_out is not zero, before calling deflateParams(). 716 Then no more input data should be provided before the deflateParams() call. 717 If this is done, the old level and strategy will be applied to the data 718 compressed before deflateParams(), and the new level and strategy will be 719 applied to the the data compressed after deflateParams(). 720 721 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 722 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 723 there was not enough output space to complete the compression of the 724 available input data before a change in the strategy or approach. Note that 725 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 726 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 727 retried with more output space. 728 */ 729 730 Z_EXTERN Z_EXPORT 731 int32_t zng_deflateTune(zng_stream *strm, int32_t good_length, int32_t max_lazy, int32_t nice_length, int32_t max_chain); 732 /* 733 Fine tune deflate's internal compression parameters. This should only be 734 used by someone who understands the algorithm used by zlib's deflate for 735 searching for the best matching string, and even then only by the most 736 fanatic optimizer trying to squeeze out the last compressed bit for their 737 specific input data. Read the deflate.c source code for the meaning of the 738 max_lazy, good_length, nice_length, and max_chain parameters. 739 740 deflateTune() can be called after deflateInit() or deflateInit2(), and 741 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 742 */ 743 744 Z_EXTERN Z_EXPORT 745 unsigned long zng_deflateBound(zng_stream *strm, unsigned long sourceLen); 746 /* 747 deflateBound() returns an upper bound on the compressed size after 748 deflation of sourceLen bytes. It must be called after deflateInit() or 749 deflateInit2(), and after deflateSetHeader(), if used. This would be used 750 to allocate an output buffer for deflation in a single pass, and so would be 751 called before deflate(). If that first deflate() call is provided the 752 sourceLen input bytes, an output buffer allocated to the size returned by 753 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 754 to return Z_STREAM_END. Note that it is possible for the compressed size to 755 be larger than the value returned by deflateBound() if flush options other 756 than Z_FINISH or Z_NO_FLUSH are used. 757 */ 758 759 Z_EXTERN Z_EXPORT 760 int32_t zng_deflatePending(zng_stream *strm, uint32_t *pending, int32_t *bits); 761 /* 762 deflatePending() returns the number of bytes and bits of output that have 763 been generated, but not yet provided in the available output. The bytes not 764 provided would be due to the available output space having being consumed. 765 The number of bits of output not provided are between 0 and 7, where they 766 await more bits to join them in order to fill out a full byte. If pending 767 or bits are NULL, then those values are not set. 768 769 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 770 stream state was inconsistent. 771 */ 772 773 Z_EXTERN Z_EXPORT 774 int32_t zng_deflatePrime(zng_stream *strm, int32_t bits, int32_t value); 775 /* 776 deflatePrime() inserts bits in the deflate output stream. The intent 777 is that this function is used to start off the deflate output with the bits 778 leftover from a previous deflate stream when appending to it. As such, this 779 function can only be used for raw deflate, and must be used before the first 780 deflate() call after a deflateInit2() or deflateReset(). bits must be less 781 than or equal to 16, and that many of the least significant bits of value 782 will be inserted in the output. 783 784 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 785 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 786 source stream state was inconsistent. 787 */ 788 789 Z_EXTERN Z_EXPORT 790 int32_t zng_deflateSetHeader(zng_stream *strm, zng_gz_headerp head); 791 /* 792 deflateSetHeader() provides gzip header information for when a gzip 793 stream is requested by deflateInit2(). deflateSetHeader() may be called 794 after deflateInit2() or deflateReset() and before the first call of 795 deflate(). The text, time, os, extra field, name, and comment information 796 in the provided zng_gz_header structure are written to the gzip header (xflag is 797 ignored -- the extra flags are set according to the compression level). The 798 caller must assure that, if not NULL, name and comment are terminated with 799 a zero byte, and that if extra is not NULL, that extra_len bytes are 800 available there. If hcrc is true, a gzip header crc is included. Note that 801 the current versions of the command-line version of gzip (up through version 802 1.3.x) do not support header crc's, and will report that it is a "multi-part 803 gzip file" and give up. 804 805 If deflateSetHeader is not used, the default gzip header has text false, 806 the time set to zero, and os set to 255, with no extra, name, or comment 807 fields. The gzip header is returned to the default state by deflateReset(). 808 809 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 810 stream state was inconsistent. 811 */ 812 813 /* 814 Z_EXTERN Z_EXPORT 815 int zng_inflateInit2(zng_stream *strm, int windowBits); 816 817 This is another version of inflateInit with an extra parameter. The 818 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 819 before by the caller. 820 821 The windowBits parameter is the base two logarithm of the maximum window 822 size (the size of the history buffer). It should be in the range 8..15 for 823 this version of the library. The default value is 15 if inflateInit is used 824 instead. windowBits must be greater than or equal to the windowBits value 825 provided to deflateInit2() while compressing, or it must be equal to 15 if 826 deflateInit2() was not used. If a compressed stream with a larger window 827 size is given as input, inflate() will return with the error code 828 Z_DATA_ERROR instead of trying to allocate a larger window. 829 830 windowBits can also be zero to request that inflate use the window size in 831 the zlib header of the compressed stream. 832 833 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 834 determines the window size. inflate() will then process raw deflate data, 835 not looking for a zlib or gzip header, not generating a check value, and not 836 looking for any check values for comparison at the end of the stream. This 837 is for use with other formats that use the deflate compressed data format 838 such as zip. Those formats provide their own check values. If a custom 839 format is developed using the raw deflate format for compressed data, it is 840 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 841 the uncompressed data as is done in the zlib, gzip, and zip formats. For 842 most applications, the zlib format should be used as is. Note that comments 843 above on the use in deflateInit2() applies to the magnitude of windowBits. 844 845 windowBits can also be greater than 15 for optional gzip decoding. Add 846 32 to windowBits to enable zlib and gzip decoding with automatic header 847 detection, or add 16 to decode only the gzip format (the zlib format will 848 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 849 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 850 below), inflate() will *not* automatically decode concatenated gzip members. 851 inflate() will return Z_STREAM_END at the end of the gzip member. The state 852 would need to be reset to continue decoding a subsequent gzip member. This 853 *must* be done if there is more data after a gzip member, in order for the 854 decompression to be compliant with the gzip standard (RFC 1952). 855 856 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 857 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 858 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 859 invalid, such as a null pointer to the structure. msg is set to null if 860 there is no error message. inflateInit2 does not perform any decompression 861 apart from possibly reading the zlib header if present: actual decompression 862 will be done by inflate(). (So next_in and avail_in may be modified, but 863 next_out and avail_out are unused and unchanged.) The current implementation 864 of inflateInit2() does not process any header information -- that is 865 deferred until inflate() is called. 866 */ 867 868 Z_EXTERN Z_EXPORT 869 int32_t zng_inflateSetDictionary(zng_stream *strm, const uint8_t *dictionary, uint32_t dictLength); 870 /* 871 Initializes the decompression dictionary from the given uncompressed byte 872 sequence. This function must be called immediately after a call of inflate, 873 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 874 can be determined from the Adler-32 value returned by that call of inflate. 875 The compressor and decompressor must use exactly the same dictionary (see 876 deflateSetDictionary). For raw inflate, this function can be called at any 877 time to set the dictionary. If the provided dictionary is smaller than the 878 window and there is already data in the window, then the provided dictionary 879 will amend what's there. The application must insure that the dictionary 880 that was used for compression is provided. 881 882 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 883 parameter is invalid (e.g. dictionary being NULL) or the stream state is 884 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 885 expected one (incorrect Adler-32 value). inflateSetDictionary does not 886 perform any decompression: this will be done by subsequent calls of 887 inflate(). 888 */ 889 890 Z_EXTERN Z_EXPORT 891 int32_t zng_inflateGetDictionary(zng_stream *strm, uint8_t *dictionary, uint32_t *dictLength); 892 /* 893 Returns the sliding dictionary being maintained by inflate. dictLength is 894 set to the number of bytes in the dictionary, and that many bytes are copied 895 to dictionary. dictionary must have enough space, where 32768 bytes is 896 always enough. If inflateGetDictionary() is called with dictionary equal to 897 NULL, then only the dictionary length is returned, and nothing is copied. 898 Similary, if dictLength is NULL, then it is not set. 899 900 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 901 stream state is inconsistent. 902 */ 903 904 Z_EXTERN Z_EXPORT 905 int32_t zng_inflateSync(zng_stream *strm); 906 /* 907 Skips invalid compressed data until a possible full flush point (see above 908 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 909 available input is skipped. No output is provided. 910 911 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 912 All full flush points have this pattern, but not all occurrences of this 913 pattern are full flush points. 914 915 inflateSync returns Z_OK if a possible full flush point has been found, 916 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 917 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 918 In the success case, the application may save the current current value of 919 total_in which indicates where valid compressed data was found. In the 920 error case, the application may repeatedly call inflateSync, providing more 921 input each time, until success or end of the input data. 922 */ 923 924 Z_EXTERN Z_EXPORT 925 int32_t zng_inflateCopy(zng_stream *dest, zng_stream *source); 926 /* 927 Sets the destination stream as a complete copy of the source stream. 928 929 This function can be useful when randomly accessing a large stream. The 930 first pass through the stream can periodically record the inflate state, 931 allowing restarting inflate at those points when randomly accessing the 932 stream. 933 934 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 935 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 936 (such as zalloc being NULL). msg is left unchanged in both source and 937 destination. 938 */ 939 940 Z_EXTERN Z_EXPORT 941 int32_t zng_inflateReset(zng_stream *strm); 942 /* 943 This function is equivalent to inflateEnd followed by inflateInit, 944 but does not free and reallocate the internal decompression state. The 945 stream will keep attributes that may have been set by inflateInit2. 946 947 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 948 stream state was inconsistent (such as zalloc or state being NULL). 949 */ 950 951 Z_EXTERN Z_EXPORT 952 int32_t zng_inflateReset2(zng_stream *strm, int32_t windowBits); 953 /* 954 This function is the same as inflateReset, but it also permits changing 955 the wrap and window size requests. The windowBits parameter is interpreted 956 the same as it is for inflateInit2. If the window size is changed, then the 957 memory allocated for the window is freed, and the window will be reallocated 958 by inflate() if needed. 959 960 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 961 stream state was inconsistent (such as zalloc or state being NULL), or if 962 the windowBits parameter is invalid. 963 */ 964 965 Z_EXTERN Z_EXPORT 966 int32_t zng_inflatePrime(zng_stream *strm, int32_t bits, int32_t value); 967 /* 968 This function inserts bits in the inflate input stream. The intent is 969 that this function is used to start inflating at a bit position in the 970 middle of a byte. The provided bits will be used before any bytes are used 971 from next_in. This function should only be used with raw inflate, and 972 should be used before the first inflate() call after inflateInit2() or 973 inflateReset(). bits must be less than or equal to 16, and that many of the 974 least significant bits of value will be inserted in the input. 975 976 If bits is negative, then the input stream bit buffer is emptied. Then 977 inflatePrime() can be called again to put bits in the buffer. This is used 978 to clear out bits leftover after feeding inflate a block description prior 979 to feeding inflate codes. 980 981 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 982 stream state was inconsistent. 983 */ 984 985 Z_EXTERN Z_EXPORT 986 long zng_inflateMark(zng_stream *strm); 987 /* 988 This function returns two values, one in the lower 16 bits of the return 989 value, and the other in the remaining upper bits, obtained by shifting the 990 return value down 16 bits. If the upper value is -1 and the lower value is 991 zero, then inflate() is currently decoding information outside of a block. 992 If the upper value is -1 and the lower value is non-zero, then inflate is in 993 the middle of a stored block, with the lower value equaling the number of 994 bytes from the input remaining to copy. If the upper value is not -1, then 995 it is the number of bits back from the current bit position in the input of 996 the code (literal or length/distance pair) currently being processed. In 997 that case the lower value is the number of bytes already emitted for that 998 code. 999 1000 A code is being processed if inflate is waiting for more input to complete 1001 decoding of the code, or if it has completed decoding but is waiting for 1002 more output space to write the literal or match data. 1003 1004 inflateMark() is used to mark locations in the input data for random 1005 access, which may be at bit positions, and to note those cases where the 1006 output of a code may span boundaries of random access blocks. The current 1007 location in the input stream can be determined from avail_in and data_type 1008 as noted in the description for the Z_BLOCK flush parameter for inflate. 1009 1010 inflateMark returns the value noted above, or -65536 if the provided 1011 source stream state was inconsistent. 1012 */ 1013 1014 Z_EXTERN Z_EXPORT 1015 int32_t zng_inflateGetHeader(zng_stream *strm, zng_gz_headerp head); 1016 /* 1017 inflateGetHeader() requests that gzip header information be stored in the 1018 provided zng_gz_header structure. inflateGetHeader() may be called after 1019 inflateInit2() or inflateReset(), and before the first call of inflate(). 1020 As inflate() processes the gzip stream, head->done is zero until the header 1021 is completed, at which time head->done is set to one. If a zlib stream is 1022 being decoded, then head->done is set to -1 to indicate that there will be 1023 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1024 used to force inflate() to return immediately after header processing is 1025 complete and before any actual data is decompressed. 1026 1027 The text, time, xflags, and os fields are filled in with the gzip header 1028 contents. hcrc is set to true if there is a header CRC. (The header CRC 1029 was valid if done is set to one.) If extra is not NULL, then extra_max 1030 contains the maximum number of bytes to write to extra. Once done is true, 1031 extra_len contains the actual extra field length, and extra contains the 1032 extra field, or that field truncated if extra_max is less than extra_len. 1033 If name is not NULL, then up to name_max characters are written there, 1034 terminated with a zero unless the length is greater than name_max. If 1035 comment is not NULL, then up to comm_max characters are written there, 1036 terminated with a zero unless the length is greater than comm_max. When any 1037 of extra, name, or comment are not NULL and the respective field is not 1038 present in the header, then that field is set to NULL to signal its 1039 absence. This allows the use of deflateSetHeader() with the returned 1040 structure to duplicate the header. However if those fields are set to 1041 allocated memory, then the application will need to save those pointers 1042 elsewhere so that they can be eventually freed. 1043 1044 If inflateGetHeader is not used, then the header information is simply 1045 discarded. The header is always checked for validity, including the header 1046 CRC if present. inflateReset() will reset the process to discard the header 1047 information. The application would need to call inflateGetHeader() again to 1048 retrieve the header from the next gzip stream. 1049 1050 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1051 stream state was inconsistent. 1052 */ 1053 1054 /* 1055 Z_EXTERN Z_EXPORT 1056 int zng_inflateBackInit(zng_stream *strm, int windowBits, unsigned char *window); 1057 1058 Initialize the internal stream state for decompression using inflateBack() 1059 calls. The fields zalloc, zfree and opaque in strm must be initialized 1060 before the call. If zalloc and zfree are NULL, then the default library- 1061 derived memory allocation routines are used. windowBits is the base two 1062 logarithm of the window size, in the range 8..15. window is a caller 1063 supplied buffer of that size. Except for special applications where it is 1064 assured that deflate was used with small window sizes, windowBits must be 15 1065 and a 32K byte window must be supplied to be able to decompress general 1066 deflate streams. 1067 1068 See inflateBack() for the usage of these routines. 1069 1070 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1071 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1072 allocated, or Z_VERSION_ERROR if the version of the library does not match 1073 the version of the header file. 1074 */ 1075 1076 typedef uint32_t (*in_func) (void *, const uint8_t * *); 1077 typedef int32_t (*out_func) (void *, uint8_t *, uint32_t); 1078 1079 Z_EXTERN Z_EXPORT 1080 int32_t zng_inflateBack(zng_stream *strm, in_func in, void *in_desc, out_func out, void *out_desc); 1081 /* 1082 inflateBack() does a raw inflate with a single call using a call-back 1083 interface for input and output. This is potentially more efficient than 1084 inflate() for file i/o applications, in that it avoids copying between the 1085 output and the sliding window by simply making the window itself the output 1086 buffer. inflate() can be faster on modern CPUs when used with large 1087 buffers. inflateBack() trusts the application to not change the output 1088 buffer passed by the output function, at least until inflateBack() returns. 1089 1090 inflateBackInit() must be called first to allocate the internal state 1091 and to initialize the state with the user-provided window buffer. 1092 inflateBack() may then be used multiple times to inflate a complete, raw 1093 deflate stream with each call. inflateBackEnd() is then called to free the 1094 allocated state. 1095 1096 A raw deflate stream is one with no zlib or gzip header or trailer. 1097 This routine would normally be used in a utility that reads zip or gzip 1098 files and writes out uncompressed files. The utility would decode the 1099 header and process the trailer on its own, hence this routine expects only 1100 the raw deflate stream to decompress. This is different from the default 1101 behavior of inflate(), which expects a zlib header and trailer around the 1102 deflate stream. 1103 1104 inflateBack() uses two subroutines supplied by the caller that are then 1105 called by inflateBack() for input and output. inflateBack() calls those 1106 routines until it reads a complete deflate stream and writes out all of the 1107 uncompressed data, or until it encounters an error. The function's 1108 parameters and return types are defined above in the in_func and out_func 1109 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1110 number of bytes of provided input, and a pointer to that input in buf. If 1111 there is no input available, in() must return zero -- buf is ignored in that 1112 case -- and inflateBack() will return a buffer error. inflateBack() will 1113 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 1114 out() should return zero on success, or non-zero on failure. If out() 1115 returns non-zero, inflateBack() will return with an error. Neither in() nor 1116 out() are permitted to change the contents of the window provided to 1117 inflateBackInit(), which is also the buffer that out() uses to write from. 1118 The length written by out() will be at most the window size. Any non-zero 1119 amount of input may be provided by in(). 1120 1121 For convenience, inflateBack() can be provided input on the first call by 1122 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1123 in() will be called. Therefore strm->next_in must be initialized before 1124 calling inflateBack(). If strm->next_in is NULL, then in() will be called 1125 immediately for input. If strm->next_in is not NULL, then strm->avail_in 1126 must also be initialized, and then if strm->avail_in is not zero, input will 1127 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1128 1129 The in_desc and out_desc parameters of inflateBack() is passed as the 1130 first parameter of in() and out() respectively when they are called. These 1131 descriptors can be optionally used to pass any information that the caller- 1132 supplied in() and out() functions need to do their job. 1133 1134 On return, inflateBack() will set strm->next_in and strm->avail_in to 1135 pass back any unused input that was provided by the last in() call. The 1136 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1137 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1138 in the deflate stream (in which case strm->msg is set to indicate the nature 1139 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1140 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1141 using strm->next_in which will be NULL only if in() returned an error. If 1142 strm->next_in is not NULL, then the Z_BUF_ERROR was due to out() returning 1143 non-zero. (in() will always be called before out(), so strm->next_in is 1144 assured to be defined if out() returns non-zero.) Note that inflateBack() 1145 cannot return Z_OK. 1146 */ 1147 1148 Z_EXTERN Z_EXPORT 1149 int32_t zng_inflateBackEnd(zng_stream *strm); 1150 /* 1151 All memory allocated by inflateBackInit() is freed. 1152 1153 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1154 state was inconsistent. 1155 */ 1156 1157 Z_EXTERN Z_EXPORT 1158 unsigned long zng_zlibCompileFlags(void); 1159 /* Return flags indicating compile-time options. 1160 1161 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1162 1.0: size of unsigned int 1163 3.2: size of unsigned long 1164 5.4: size of void * (pointer) 1165 7.6: size of z_off_t 1166 1167 Compiler, assembler, and debug options: 1168 8: ZLIB_DEBUG 1169 9: ASMV or ASMINF -- use ASM code 1170 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1171 11: 0 (reserved) 1172 1173 One-time table building (smaller code, but not thread-safe if true): 1174 12: BUILDFIXED -- build static block decoding tables when needed (not supported by zlib-ng) 1175 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1176 14,15: 0 (reserved) 1177 1178 Library content (indicates missing functionality): 1179 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1180 deflate code when not needed) 1181 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1182 and decode gzip streams (to avoid linking crc code) 1183 18-19: 0 (reserved) 1184 1185 Operation variations (changes in library functionality): 1186 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1187 21: FASTEST -- deflate algorithm with only one, lowest compression level 1188 22,23: 0 (reserved) 1189 1190 The sprintf variant used by gzprintf (zero is best): 1191 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1192 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1193 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1194 1195 Remainder: 1196 27-31: 0 (reserved) 1197 */ 1198 1199 1200 /* utility functions */ 1201 1202 /* 1203 The following utility functions are implemented on top of the basic 1204 stream-oriented functions. To simplify the interface, some default options 1205 are assumed (compression level and memory usage, standard memory allocation 1206 functions). The source code of these utility functions can be modified if 1207 you need special options. 1208 */ 1209 1210 Z_EXTERN Z_EXPORT 1211 int32_t zng_compress(uint8_t *dest, size_t *destLen, const uint8_t *source, size_t sourceLen); 1212 /* 1213 Compresses the source buffer into the destination buffer. sourceLen is 1214 the byte length of the source buffer. Upon entry, destLen is the total size 1215 of the destination buffer, which must be at least the value returned by 1216 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1217 compressed data. compress() is equivalent to compress2() with a level 1218 parameter of Z_DEFAULT_COMPRESSION. 1219 1220 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1221 enough memory, Z_BUF_ERROR if there was not enough room in the output 1222 buffer. 1223 */ 1224 1225 Z_EXTERN Z_EXPORT 1226 int32_t zng_compress2(uint8_t *dest, size_t *destLen, const uint8_t *source, size_t sourceLen, int32_t level); 1227 /* 1228 Compresses the source buffer into the destination buffer. The level 1229 parameter has the same meaning as in deflateInit. sourceLen is the byte 1230 length of the source buffer. Upon entry, destLen is the total size of the 1231 destination buffer, which must be at least the value returned by 1232 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1233 compressed data. 1234 1235 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1236 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1237 Z_STREAM_ERROR if the level parameter is invalid. 1238 */ 1239 1240 Z_EXTERN Z_EXPORT 1241 size_t zng_compressBound(size_t sourceLen); 1242 /* 1243 compressBound() returns an upper bound on the compressed size after 1244 compress() or compress2() on sourceLen bytes. It would be used before a 1245 compress() or compress2() call to allocate the destination buffer. 1246 */ 1247 1248 Z_EXTERN Z_EXPORT 1249 int32_t zng_uncompress(uint8_t *dest, size_t *destLen, const uint8_t *source, size_t sourceLen); 1250 /* 1251 Decompresses the source buffer into the destination buffer. sourceLen is 1252 the byte length of the source buffer. Upon entry, destLen is the total size 1253 of the destination buffer, which must be large enough to hold the entire 1254 uncompressed data. (The size of the uncompressed data must have been saved 1255 previously by the compressor and transmitted to the decompressor by some 1256 mechanism outside the scope of this compression library.) Upon exit, destLen 1257 is the actual size of the uncompressed data. 1258 1259 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1260 enough memory, Z_BUF_ERROR if there was not enough room in the output 1261 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1262 the case where there is not enough room, uncompress() will fill the output 1263 buffer with the uncompressed data up to that point. 1264 */ 1265 1266 1267 Z_EXTERN Z_EXPORT 1268 int32_t zng_uncompress2(uint8_t *dest, size_t *destLen, const uint8_t *source, size_t *sourceLen); 1269 /* 1270 Same as uncompress, except that sourceLen is a pointer, where the 1271 length of the source is *sourceLen. On return, *sourceLen is the number of 1272 source bytes consumed. 1273 */ 1274 1275 1276 #ifdef WITH_GZFILEOP 1277 /* gzip file access functions */ 1278 1279 /* 1280 This library supports reading and writing files in gzip (.gz) format with 1281 an interface similar to that of stdio, using the functions that start with 1282 "gz". The gzip format is different from the zlib format. gzip is a gzip 1283 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1284 */ 1285 1286 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1287 1288 Z_EXTERN Z_EXPORT 1289 gzFile zng_gzopen(const char *path, const char *mode); 1290 /* 1291 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 1292 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 1293 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 1294 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 1295 for fixed code compression as in "wb9F". (See the description of 1296 deflateInit2 for more information about the strategy parameter.) 'T' will 1297 request transparent writing or appending with no compression and not using 1298 the gzip format. 1299 1300 "a" can be used instead of "w" to request that the gzip stream that will 1301 be written be appended to the file. "+" will result in an error, since 1302 reading and writing to the same gzip file is not supported. The addition of 1303 "x" when writing will create the file exclusively, which fails if the file 1304 already exists. On systems that support it, the addition of "e" when 1305 reading or writing will set the flag to close the file on an execve() call. 1306 1307 These functions, as well as gzip, will read and decode a sequence of gzip 1308 streams in a file. The append function of gzopen() can be used to create 1309 such a file. (Also see gzflush() for another way to do this.) When 1310 appending, gzopen does not test whether the file begins with a gzip stream, 1311 nor does it look for the end of the gzip streams to begin appending. gzopen 1312 will simply append a gzip stream to the existing file. 1313 1314 gzopen can be used to read a file which is not in gzip format; in this 1315 case gzread will directly read from the file without decompression. When 1316 reading, this will be detected automatically by looking for the magic two- 1317 byte gzip header. 1318 1319 gzopen returns NULL if the file could not be opened, if there was 1320 insufficient memory to allocate the gzFile state, or if an invalid mode was 1321 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1322 errno can be checked to determine if the reason gzopen failed was that the 1323 file could not be opened. 1324 */ 1325 1326 Z_EXTERN Z_EXPORT 1327 gzFile zng_gzdopen(int fd, const char *mode); 1328 /* 1329 gzdopen associates a gzFile with the file descriptor fd. File descriptors 1330 are obtained from calls like open, dup, creat, pipe or fileno (if the file 1331 has been previously opened with fopen). The mode parameter is as in gzopen. 1332 1333 The next call of gzclose on the returned gzFile will also close the file 1334 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1335 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1336 mode);. The duplicated descriptor should be saved to avoid a leak, since 1337 gzdopen does not close fd if it fails. If you are using fileno() to get the 1338 file descriptor from a FILE *, then you will have to use dup() to avoid 1339 double-close()ing the file descriptor. Both gzclose() and fclose() will 1340 close the associated file descriptor, so they need to have different file 1341 descriptors. 1342 1343 gzdopen returns NULL if there was insufficient memory to allocate the 1344 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1345 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1346 used until the next gz* read, write, seek, or close operation, so gzdopen 1347 will not detect if fd is invalid (unless fd is -1). 1348 */ 1349 1350 Z_EXTERN Z_EXPORT 1351 int32_t zng_gzbuffer(gzFile file, uint32_t size); 1352 /* 1353 Set the internal buffer size used by this library's functions. The 1354 default buffer size is 8192 bytes. This function must be called after 1355 gzopen() or gzdopen(), and before any other calls that read or write the 1356 file. The buffer memory allocation is always deferred to the first read or 1357 write. Three times that size in buffer space is allocated. A larger buffer 1358 size of, for example, 64K or 128K bytes will noticeably increase the speed 1359 of decompression (reading). 1360 1361 The new buffer size also affects the maximum length for gzprintf(). 1362 1363 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1364 too late. 1365 */ 1366 1367 Z_EXTERN Z_EXPORT 1368 int32_t zng_gzsetparams(gzFile file, int32_t level, int32_t strategy); 1369 /* 1370 Dynamically update the compression level or strategy. See the description 1371 of deflateInit2 for the meaning of these parameters. Previously provided 1372 data is flushed before the parameter change. 1373 1374 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1375 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1376 or Z_MEM_ERROR if there is a memory allocation error. 1377 */ 1378 1379 Z_EXTERN Z_EXPORT 1380 int32_t zng_gzread(gzFile file, void *buf, uint32_t len); 1381 /* 1382 Reads the given number of uncompressed bytes from the compressed file. If 1383 the input file is not in gzip format, gzread copies the given number of 1384 bytes into the buffer directly from the file. 1385 1386 After reaching the end of a gzip stream in the input, gzread will continue 1387 to read, looking for another gzip stream. Any number of gzip streams may be 1388 concatenated in the input file, and will all be decompressed by gzread(). 1389 If something other than a gzip stream is encountered after a gzip stream, 1390 that remaining trailing garbage is ignored (and no error is returned). 1391 1392 gzread can be used to read a gzip file that is being concurrently written. 1393 Upon reaching the end of the input, gzread will return with the available 1394 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1395 gzclearerr can be used to clear the end of file indicator in order to permit 1396 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1397 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1398 middle of a gzip stream. Note that gzread does not return -1 in the event 1399 of an incomplete gzip stream. This error is deferred until gzclose(), which 1400 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1401 stream. Alternatively, gzerror can be used before gzclose to detect this 1402 case. 1403 1404 gzread returns the number of uncompressed bytes actually read, less than 1405 len for end of file, or -1 for error. If len is too large to fit in an int, 1406 then nothing is read, -1 is returned, and the error state is set to 1407 Z_STREAM_ERROR. 1408 */ 1409 1410 Z_EXTERN Z_EXPORT 1411 size_t zng_gzfread(void *buf, size_t size, size_t nitems, gzFile file); 1412 /* 1413 Read up to nitems items of size size from file to buf, otherwise operating 1414 as gzread() does. This duplicates the interface of stdio's fread(), with 1415 size_t request and return types. 1416 1417 gzfread() returns the number of full items read of size size, or zero if 1418 the end of the file was reached and a full item could not be read, or if 1419 there was an error. gzerror() must be consulted if zero is returned in 1420 order to determine if there was an error. If the multiplication of size and 1421 nitems overflows, i.e. the product does not fit in a size_t, then nothing 1422 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1423 1424 In the event that the end of file is reached and only a partial item is 1425 available at the end, i.e. the remaining uncompressed data length is not a 1426 multiple of size, then the final partial item is nevertheless read into buf 1427 and the end-of-file flag is set. The length of the partial item read is not 1428 provided, but could be inferred from the result of gztell(). This behavior 1429 is the same as the behavior of fread() implementations in common libraries, 1430 but it prevents the direct use of gzfread() to read a concurrently written 1431 file, reseting and retrying on end-of-file, when size is not 1. 1432 */ 1433 1434 Z_EXTERN Z_EXPORT 1435 int32_t zng_gzwrite(gzFile file, void const *buf, uint32_t len); 1436 /* 1437 Writes the given number of uncompressed bytes into the compressed file. 1438 gzwrite returns the number of uncompressed bytes written or 0 in case of 1439 error. 1440 */ 1441 1442 Z_EXTERN Z_EXPORT 1443 size_t zng_gzfwrite(void const *buf, size_t size, size_t nitems, gzFile file); 1444 /* 1445 gzfwrite() writes nitems items of size size from buf to file, duplicating 1446 the interface of stdio's fwrite(), with size_t request and return types. 1447 1448 gzfwrite() returns the number of full items written of size size, or zero 1449 if there was an error. If the multiplication of size and nitems overflows, 1450 i.e. the product does not fit in a size_t, then nothing is written, zero 1451 is returned, and the error state is set to Z_STREAM_ERROR. 1452 */ 1453 1454 Z_EXTERN Z_EXPORTVA 1455 int32_t zng_gzprintf(gzFile file, const char *format, ...); 1456 /* 1457 Converts, formats, and writes the arguments to the compressed file under 1458 control of the format string, as in fprintf. gzprintf returns the number of 1459 uncompressed bytes actually written, or a negative zlib error code in case 1460 of error. The number of uncompressed bytes written is limited to 8191, or 1461 one less than the buffer size given to gzbuffer(). The caller should assure 1462 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1463 return an error (0) with nothing written. In this case, there may also be a 1464 buffer overflow with unpredictable consequences, which is possible only if 1465 zlib was compiled with the insecure functions sprintf() or vsprintf() 1466 because the secure snprintf() or vsnprintf() functions were not available. 1467 This can be determined using zlibCompileFlags(). 1468 */ 1469 1470 Z_EXTERN Z_EXPORT 1471 int32_t zng_gzputs(gzFile file, const char *s); 1472 /* 1473 Writes the given null-terminated string to the compressed file, excluding 1474 the terminating null character. 1475 1476 gzputs returns the number of characters written, or -1 in case of error. 1477 */ 1478 1479 Z_EXTERN Z_EXPORT 1480 char * zng_gzgets(gzFile file, char *buf, int32_t len); 1481 /* 1482 Reads bytes from the compressed file until len-1 characters are read, or a 1483 newline character is read and transferred to buf, or an end-of-file 1484 condition is encountered. If any characters are read or if len == 1, the 1485 string is terminated with a null character. If no characters are read due 1486 to an end-of-file or len < 1, then the buffer is left untouched. 1487 1488 gzgets returns buf which is a null-terminated string, or it returns NULL 1489 for end-of-file or in case of error. If there was an error, the contents at 1490 buf are indeterminate. 1491 */ 1492 1493 Z_EXTERN Z_EXPORT 1494 int32_t zng_gzputc(gzFile file, int32_t c); 1495 /* 1496 Writes c, converted to an unsigned char, into the compressed file. gzputc 1497 returns the value that was written, or -1 in case of error. 1498 */ 1499 1500 Z_EXTERN Z_EXPORT 1501 int32_t zng_gzgetc(gzFile file); 1502 /* 1503 Reads one byte from the compressed file. gzgetc returns this byte or -1 1504 in case of end of file or error. This is implemented as a macro for speed. 1505 As such, it does not do all of the checking the other functions do. I.e. 1506 it does not check to see if file is NULL, nor whether the structure file 1507 points to has been clobbered or not. 1508 */ 1509 1510 Z_EXTERN Z_EXPORT 1511 int32_t zng_gzungetc(int32_t c, gzFile file); 1512 /* 1513 Push one character back onto the stream to be read as the first character 1514 on the next read. At least one character of push-back is allowed. 1515 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1516 fail if c is -1, and may fail if a character has been pushed but not read 1517 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1518 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1519 The pushed character will be discarded if the stream is repositioned with 1520 gzseek() or gzrewind(). 1521 */ 1522 1523 Z_EXTERN Z_EXPORT 1524 int32_t zng_gzflush(gzFile file, int32_t flush); 1525 /* 1526 Flushes all pending output into the compressed file. The parameter flush 1527 is as in the deflate() function. The return value is the zlib error number 1528 (see function gzerror below). gzflush is only permitted when writing. 1529 1530 If the flush parameter is Z_FINISH, the remaining data is written and the 1531 gzip stream is completed in the output. If gzwrite() is called again, a new 1532 gzip stream will be started in the output. gzread() is able to read such 1533 concatenated gzip streams. 1534 1535 gzflush should be called only when strictly necessary because it will 1536 degrade compression if called too often. 1537 */ 1538 1539 Z_EXTERN Z_EXPORT 1540 z_off64_t zng_gzseek(gzFile file, z_off64_t offset, int whence); 1541 /* 1542 Sets the starting position for the next gzread or gzwrite on the given 1543 compressed file. The offset represents a number of bytes in the 1544 uncompressed data stream. The whence parameter is defined as in lseek(2); 1545 the value SEEK_END is not supported. 1546 1547 If the file is opened for reading, this function is emulated but can be 1548 extremely slow. If the file is opened for writing, only forward seeks are 1549 supported; gzseek then compresses a sequence of zeroes up to the new 1550 starting position. 1551 1552 gzseek returns the resulting offset location as measured in bytes from 1553 the beginning of the uncompressed stream, or -1 in case of error, in 1554 particular if the file is opened for writing and the new starting position 1555 would be before the current position. 1556 */ 1557 1558 Z_EXTERN Z_EXPORT 1559 int32_t zng_gzrewind(gzFile file); 1560 /* 1561 Rewinds the given file. This function is supported only for reading. 1562 1563 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1564 */ 1565 1566 Z_EXTERN Z_EXPORT 1567 z_off64_t zng_gztell(gzFile file); 1568 /* 1569 Returns the starting position for the next gzread or gzwrite on the given 1570 compressed file. This position represents a number of bytes in the 1571 uncompressed data stream, and is zero when starting, even if appending or 1572 reading a gzip stream from the middle of a file using gzdopen(). 1573 1574 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1575 */ 1576 1577 Z_EXTERN Z_EXPORT 1578 z_off64_t zng_gzoffset(gzFile file); 1579 /* 1580 Returns the current offset in the file being read or written. This offset 1581 includes the count of bytes that precede the gzip stream, for example when 1582 appending or when using gzdopen() for reading. When reading, the offset 1583 does not include as yet unused buffered input. This information can be used 1584 for a progress indicator. On error, gzoffset() returns -1. 1585 */ 1586 1587 Z_EXTERN Z_EXPORT 1588 int32_t zng_gzeof(gzFile file); 1589 /* 1590 Returns true (1) if the end-of-file indicator has been set while reading, 1591 false (0) otherwise. Note that the end-of-file indicator is set only if the 1592 read tried to go past the end of the input, but came up short. Therefore, 1593 just like feof(), gzeof() may return false even if there is no more data to 1594 read, in the event that the last read request was for the exact number of 1595 bytes remaining in the input file. This will happen if the input file size 1596 is an exact multiple of the buffer size. 1597 1598 If gzeof() returns true, then the read functions will return no more data, 1599 unless the end-of-file indicator is reset by gzclearerr() and the input file 1600 has grown since the previous end of file was detected. 1601 */ 1602 1603 Z_EXTERN Z_EXPORT 1604 int32_t zng_gzdirect(gzFile file); 1605 /* 1606 Returns true (1) if file is being copied directly while reading, or false 1607 (0) if file is a gzip stream being decompressed. 1608 1609 If the input file is empty, gzdirect() will return true, since the input 1610 does not contain a gzip stream. 1611 1612 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1613 cause buffers to be allocated to allow reading the file to determine if it 1614 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1615 gzdirect(). 1616 1617 When writing, gzdirect() returns true (1) if transparent writing was 1618 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1619 gzdirect() is not needed when writing. Transparent writing must be 1620 explicitly requested, so the application already knows the answer. When 1621 linking statically, using gzdirect() will include all of the zlib code for 1622 gzip file reading and decompression, which may not be desired.) 1623 */ 1624 1625 Z_EXTERN Z_EXPORT 1626 int32_t zng_gzclose(gzFile file); 1627 /* 1628 Flushes all pending output if necessary, closes the compressed file and 1629 deallocates the (de)compression state. Note that once file is closed, you 1630 cannot call gzerror with file, since its structures have been deallocated. 1631 gzclose must not be called more than once on the same file, just as free 1632 must not be called more than once on the same allocation. 1633 1634 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1635 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1636 last read ended in the middle of a gzip stream, or Z_OK on success. 1637 */ 1638 1639 Z_EXTERN Z_EXPORT 1640 int32_t zng_gzclose_r(gzFile file); 1641 Z_EXTERN Z_EXPORT 1642 int32_t zng_gzclose_w(gzFile file); 1643 /* 1644 Same as gzclose(), but gzclose_r() is only for use when reading, and 1645 gzclose_w() is only for use when writing or appending. The advantage to 1646 using these instead of gzclose() is that they avoid linking in zlib 1647 compression or decompression code that is not used when only reading or only 1648 writing respectively. If gzclose() is used, then both compression and 1649 decompression code will be included the application when linking to a static 1650 zlib library. 1651 */ 1652 1653 Z_EXTERN Z_EXPORT 1654 const char * zng_gzerror(gzFile file, int32_t *errnum); 1655 /* 1656 Returns the error message for the last error which occurred on the given 1657 compressed file. errnum is set to zlib error number. If an error occurred 1658 in the file system and not in the compression library, errnum is set to 1659 Z_ERRNO and the application may consult errno to get the exact error code. 1660 1661 The application must not modify the returned string. Future calls to 1662 this function may invalidate the previously returned string. If file is 1663 closed, then the string previously returned by gzerror will no longer be 1664 available. 1665 1666 gzerror() should be used to distinguish errors from end-of-file for those 1667 functions above that do not distinguish those cases in their return values. 1668 */ 1669 1670 Z_EXTERN Z_EXPORT 1671 void zng_gzclearerr(gzFile file); 1672 /* 1673 Clears the error and end-of-file flags for file. This is analogous to the 1674 clearerr() function in stdio. This is useful for continuing to read a gzip 1675 file that is being written concurrently. 1676 */ 1677 1678 #endif /* WITH_GZFILEOP */ 1679 1680 /* checksum functions */ 1681 1682 /* 1683 These functions are not related to compression but are exported 1684 anyway because they might be useful in applications using the compression 1685 library. 1686 */ 1687 1688 Z_EXTERN Z_EXPORT 1689 uint32_t zng_adler32(uint32_t adler, const uint8_t *buf, uint32_t len); 1690 /* 1691 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1692 return the updated checksum. If buf is NULL, this function returns the 1693 required initial value for the checksum. 1694 1695 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1696 much faster. 1697 1698 Usage example: 1699 1700 uint32_t adler = adler32(0L, NULL, 0); 1701 1702 while (read_buffer(buffer, length) != EOF) { 1703 adler = adler32(adler, buffer, length); 1704 } 1705 if (adler != original_adler) error(); 1706 */ 1707 1708 Z_EXTERN Z_EXPORT 1709 uint32_t zng_adler32_z(uint32_t adler, const uint8_t *buf, size_t len); 1710 /* 1711 Same as adler32(), but with a size_t length. 1712 */ 1713 1714 Z_EXTERN Z_EXPORT 1715 uint32_t zng_adler32_combine(uint32_t adler1, uint32_t adler2, z_off64_t len2); 1716 /* 1717 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1718 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1719 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1720 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1721 that the z_off_t type (like off_t) is a signed integer. If len2 is 1722 negative, the result has no meaning or utility. 1723 */ 1724 1725 Z_EXTERN Z_EXPORT 1726 uint32_t zng_crc32(uint32_t crc, const uint8_t *buf, uint32_t len); 1727 /* 1728 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1729 updated CRC-32. If buf is NULL, this function returns the required 1730 initial value for the crc. Pre- and post-conditioning (one's complement) is 1731 performed within this function so it shouldn't be done by the application. 1732 1733 Usage example: 1734 1735 uint32_t crc = crc32(0L, NULL, 0); 1736 1737 while (read_buffer(buffer, length) != EOF) { 1738 crc = crc32(crc, buffer, length); 1739 } 1740 if (crc != original_crc) error(); 1741 */ 1742 1743 Z_EXTERN Z_EXPORT 1744 uint32_t zng_crc32_z(uint32_t crc, const uint8_t *buf, size_t len); 1745 /* 1746 Same as crc32(), but with a size_t length. 1747 */ 1748 1749 Z_EXTERN Z_EXPORT 1750 uint32_t zng_crc32_combine(uint32_t crc1, uint32_t crc2, z_off64_t len2); 1751 1752 /* 1753 Combine two CRC-32 check values into one. For two sequences of bytes, 1754 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1755 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1756 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1757 len2. 1758 */ 1759 1760 Z_EXTERN Z_EXPORT 1761 void zng_crc32_combine_gen(uint32_t op[32], z_off64_t len2); 1762 1763 /* 1764 Generate the operator op corresponding to length len2, to be used with 1765 crc32_combine_op(). op must have room for 32 uint32_t values. (32 is the 1766 number of bits in the CRC.) 1767 */ 1768 1769 Z_EXTERN Z_EXPORT 1770 uint32_t zng_crc32_combine_op(uint32_t crc1, uint32_t crc2, const uint32_t *op); 1771 /* 1772 Give the same result as crc32_combine(), using op in place of len2. op is 1773 is generated from len2 by crc32_combine_gen(). This will be faster than 1774 crc32_combine() if the generated op is used many times. 1775 */ 1776 1777 /* various hacks, don't look :) */ 1778 1779 /* zng_deflateInit and zng_inflateInit are macros to allow checking the zlib version 1780 * and the compiler's view of zng_stream: 1781 */ 1782 Z_EXTERN Z_EXPORT int32_t zng_deflateInit_(zng_stream *strm, int32_t level, const char *version, int32_t stream_size); 1783 Z_EXTERN Z_EXPORT int32_t zng_inflateInit_(zng_stream *strm, const char *version, int32_t stream_size); 1784 Z_EXTERN Z_EXPORT int32_t zng_deflateInit2_(zng_stream *strm, int32_t level, int32_t method, int32_t windowBits, int32_t memLevel, 1785 int32_t strategy, const char *version, int32_t stream_size); 1786 Z_EXTERN Z_EXPORT int32_t zng_inflateInit2_(zng_stream *strm, int32_t windowBits, const char *version, int32_t stream_size); 1787 Z_EXTERN Z_EXPORT int32_t zng_inflateBackInit_(zng_stream *strm, int32_t windowBits, uint8_t *window, 1788 const char *version, int32_t stream_size); 1789 1790 #define zng_deflateInit(strm, level) zng_deflateInit_((strm), (level), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1791 #define zng_inflateInit(strm) zng_inflateInit_((strm), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1792 #define zng_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1793 zng_deflateInit2_((strm), (level), (method), (windowBits), (memLevel), \ 1794 (strategy), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1795 #define zng_inflateInit2(strm, windowBits) zng_inflateInit2_((strm), (windowBits), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1796 #define zng_inflateBackInit(strm, windowBits, window) \ 1797 zng_inflateBackInit_((strm), (windowBits), (window), ZLIBNG_VERSION, (int32_t)sizeof(zng_stream)) 1798 1799 #ifdef WITH_GZFILEOP 1800 1801 /* gzgetc() macro and its supporting function and exposed data structure. Note 1802 * that the real internal state is much larger than the exposed structure. 1803 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1804 * user should not mess with these exposed elements, since their names or 1805 * behavior could change in the future, perhaps even capriciously. They can 1806 * only be used by the gzgetc() macro. You have been warned. 1807 */ 1808 struct gzFile_s { 1809 unsigned have; 1810 unsigned char *next; 1811 z_off64_t pos; 1812 }; 1813 Z_EXTERN Z_EXPORT int32_t zng_gzgetc_(gzFile file); /* backward compatibility */ 1814 # define zng_gzgetc(g) ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (zng_gzgetc)(g)) 1815 1816 #endif /* WITH_GZFILEOP */ 1817 1818 1819 typedef enum { 1820 Z_DEFLATE_LEVEL = 0, /* compression level, represented as an int */ 1821 Z_DEFLATE_STRATEGY = 1, /* compression strategy, represented as an int */ 1822 Z_DEFLATE_REPRODUCIBLE = 2, 1823 /* 1824 Whether reproducible compression results are required. Represented as an int, where 0 means that it is allowed 1825 to trade reproducibility for e.g. improved performance or compression ratio, and non-0 means that 1826 reproducibility is strictly required. Reproducibility is guaranteed only when using an identical zlib-ng build. 1827 Default is 0. 1828 */ 1829 } zng_deflate_param; 1830 1831 typedef struct { 1832 zng_deflate_param param; /* parameter ID */ 1833 void *buf; /* parameter value */ 1834 size_t size; /* parameter value size */ 1835 int32_t status; /* result of the last set/get call */ 1836 } zng_deflate_param_value; 1837 1838 Z_EXTERN Z_EXPORT 1839 int32_t zng_deflateSetParams(zng_stream *strm, zng_deflate_param_value *params, size_t count); 1840 /* 1841 Sets the values of the given zlib-ng deflate stream parameters. All the buffers are copied internally, so the 1842 caller still owns them after this function returns. Returns Z_OK if success. 1843 1844 If the size of at least one of the buffers is too small to hold the entire value of the corresponding parameter, 1845 or if the same parameter is specified multiple times, Z_BUF_ERROR is returned. The caller may inspect status fields 1846 in order to determine which of the parameters caused this error. No other changes are performed. 1847 1848 If the stream state is inconsistent or if at least one of the values cannot be updated, Z_STREAM_ERROR is 1849 returned. The caller may inspect status fields in order to determine which of the parameters caused this error. 1850 Parameters, whose status field is equal to Z_OK, have been applied successfully. If all status fields are not equal 1851 to Z_STREAM_ERROR, then the error was caused by a stream state inconsistency. 1852 1853 If there are no other errors, but at least one parameter is not supported by the current zlib-ng version, 1854 Z_VERSION_ERROR is returned. The caller may inspect status fields in order to determine which of the parameters 1855 caused this error. 1856 */ 1857 1858 Z_EXTERN Z_EXPORT 1859 int32_t zng_deflateGetParams(zng_stream *strm, zng_deflate_param_value *params, size_t count); 1860 /* 1861 Copies the values of the given zlib-ng deflate stream parameters into the user-provided buffers. Returns Z_OK if 1862 success, Z_VERSION_ERROR if at least one parameter is not supported by the current zlib-ng version, Z_STREAM_ERROR 1863 if the stream state is inconsistent, and Z_BUF_ERROR if the size of at least one buffer is too small to hold the 1864 entire value of the corresponding parameter. 1865 */ 1866 1867 /* undocumented functions */ 1868 Z_EXTERN Z_EXPORT const char * zng_zError (int32_t); 1869 Z_EXTERN Z_EXPORT int32_t zng_inflateSyncPoint (zng_stream *); 1870 Z_EXTERN Z_EXPORT const uint32_t * zng_get_crc_table (void); 1871 Z_EXTERN Z_EXPORT int32_t zng_inflateUndermine (zng_stream *, int32_t); 1872 Z_EXTERN Z_EXPORT int32_t zng_inflateValidate (zng_stream *, int32_t); 1873 Z_EXTERN Z_EXPORT unsigned long zng_inflateCodesUsed (zng_stream *); 1874 Z_EXTERN Z_EXPORT int32_t zng_inflateResetKeep (zng_stream *); 1875 Z_EXTERN Z_EXPORT int32_t zng_deflateResetKeep (zng_stream *); 1876 1877 #ifdef WITH_GZFILEOP 1878 # if defined(_WIN32) 1879 Z_EXTERN Z_EXPORT gzFile zng_gzopen_w(const wchar_t *path, const char *mode); 1880 # endif 1881 Z_EXTERN Z_EXPORTVA int32_t zng_gzvprintf(gzFile file, const char *format, va_list va); 1882 #endif 1883 1884 #ifdef __cplusplus 1885 } 1886 #endif 1887 1888 #endif /* ZNGLIB_H_ */ 1889