1 /* zlib.d: modified from zlib.h by Walter Bright */ 2 /* updated from 1.2.1 to 1.2.3 by Thomas Kuehne */ 3 /* updated from 1.2.3 to 1.2.8 by Dmitry Atamanov */ 4 /* updated from 1.2.8 to 1.2.11 by Iain Buclaw */ 5 6 module etc.c.zlib; 7 8 import core.stdc.config; 9 10 /* zlib.h -- interface of the 'zlib' general purpose compression library 11 version 1.2.11, January 15th, 2017 12 13 Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler 14 15 This software is provided 'as-is', without any express or implied 16 warranty. In no event will the authors be held liable for any damages 17 arising from the use of this software. 18 19 Permission is granted to anyone to use this software for any purpose, 20 including commercial applications, and to alter it and redistribute it 21 freely, subject to the following restrictions: 22 23 1. The origin of this software must not be misrepresented; you must not 24 claim that you wrote the original software. If you use this software 25 in a product, an acknowledgment in the product documentation would be 26 appreciated but is not required. 27 2. Altered source versions must be plainly marked as such, and must not be 28 misrepresented as being the original software. 29 3. This notice may not be removed or altered from any source distribution. 30 31 Jean-loup Gailly Mark Adler 32 jloup@gzip.org madler@alumni.caltech.edu 33 34 35 The data format used by the zlib library is described by RFCs (Request for 36 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 37 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 38 */ 39 40 nothrow: 41 extern (C): 42 43 const char[] ZLIB_VERSION = "1.2.11"; 44 const ZLIB_VERNUM = 0x12b0; 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 alias alloc_func = void* function (void* opaque, uint items, uint size); 81 alias free_func = void function (void* opaque, void* address); 82 83 struct z_stream 84 { 85 const(ubyte)* next_in; /* next input byte */ 86 uint avail_in; /* number of bytes available at next_in */ 87 c_ulong total_in; /* total nb of input bytes read so far */ 88 89 ubyte* next_out; /* next output byte will go here */ 90 uint avail_out; /* remaining free space at next_out */ 91 c_ulong total_out; /* total nb of bytes output so far */ 92 93 const(char)* msg; /* last error message, NULL if no error */ 94 void* state; /* not visible by applications */ 95 96 alloc_func zalloc; /* used to allocate the internal state */ 97 free_func zfree; /* used to free the internal state */ 98 void* opaque; /* private data object passed to zalloc and zfree */ 99 100 int data_type; /* best guess about the data type: binary or text 101 for deflate, or the decoding state for inflate */ 102 c_ulong adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 103 c_ulong reserved; /* reserved for future use */ 104 } 105 106 alias z_streamp = z_stream*; 107 108 /* 109 gzip header information passed to and from zlib routines. See RFC 1952 110 for more details on the meanings of these fields. 111 */ 112 struct gz_header 113 { 114 int text; /* true if compressed data believed to be text */ 115 c_ulong time; /* modification time */ 116 int xflags; /* extra flags (not used when writing a gzip file) */ 117 int os; /* operating system */ 118 byte *extra; /* pointer to extra field or Z_NULL if none */ 119 uint extra_len; /* extra field length (valid if extra != Z_NULL) */ 120 uint extra_max; /* space at extra (only when reading header) */ 121 byte* name; /* pointer to zero-terminated file name or Z_NULL */ 122 uint name_max; /* space at name (only when reading header) */ 123 byte* comment; /* pointer to zero-terminated comment or Z_NULL */ 124 uint comm_max; /* space at comment (only when reading header) */ 125 int hcrc; /* true if there was or will be a header crc */ 126 int done; /* true when done reading gzip header (not used 127 when writing a gzip file) */ 128 } 129 130 alias gz_headerp = gz_header*; 131 132 /* 133 The application must update next_in and avail_in when avail_in has dropped 134 to zero. It must update next_out and avail_out when avail_out has dropped 135 to zero. The application must initialize zalloc, zfree and opaque before 136 calling the init function. All other fields are set by the compression 137 library and must not be updated by the application. 138 139 The opaque value provided by the application will be passed as the first 140 parameter for calls of zalloc and zfree. This can be useful for custom 141 memory management. The compression library attaches no meaning to the 142 opaque value. 143 144 zalloc must return Z_NULL if there is not enough memory for the object. 145 If zlib is used in a multi-threaded application, zalloc and zfree must be 146 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 147 Z_NULL on entry to the initialization function, they are set to internal 148 routines that use the standard library functions malloc() and free(). 149 150 On 16-bit systems, the functions zalloc and zfree must be able to allocate 151 exactly 65536 bytes, but will not be required to allocate more than this if 152 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 153 returned by zalloc for objects of exactly 65536 bytes *must* have their 154 offset normalized to zero. The default allocation function provided by this 155 library ensures this (see zutil.c). To reduce memory requirements and avoid 156 any allocation of 64K objects, at the expense of compression ratio, compile 157 the library with -DMAX_WBITS=14 (see zconf.h). 158 159 The fields total_in and total_out can be used for statistics or progress 160 reports. After compression, total_in holds the total size of the 161 uncompressed data and may be saved for use by the decompressor (particularly 162 if the decompressor wants to decompress everything in a single step). 163 */ 164 165 /* constants */ 166 167 enum 168 { 169 Z_NO_FLUSH = 0, 170 Z_PARTIAL_FLUSH = 1, /* will be removed, use Z_SYNC_FLUSH instead */ 171 Z_SYNC_FLUSH = 2, 172 Z_FULL_FLUSH = 3, 173 Z_FINISH = 4, 174 Z_BLOCK = 5, 175 Z_TREES = 6, 176 } 177 /* Allowed flush values; see deflate() and inflate() below for details */ 178 179 enum 180 { 181 Z_OK = 0, 182 Z_STREAM_END = 1, 183 Z_NEED_DICT = 2, 184 Z_ERRNO = -1, 185 Z_STREAM_ERROR = -2, 186 Z_DATA_ERROR = -3, 187 Z_MEM_ERROR = -4, 188 Z_BUF_ERROR = -5, 189 Z_VERSION_ERROR = -6, 190 } 191 /* Return codes for the compression/decompression functions. Negative 192 * values are errors, positive values are used for special but normal events. 193 */ 194 195 enum 196 { 197 Z_NO_COMPRESSION = 0, 198 Z_BEST_SPEED = 1, 199 Z_BEST_COMPRESSION = 9, 200 Z_DEFAULT_COMPRESSION = -1, 201 } 202 /* compression levels */ 203 204 enum 205 { 206 Z_FILTERED = 1, 207 Z_HUFFMAN_ONLY = 2, 208 Z_RLE = 3, 209 Z_FIXED = 4, 210 Z_DEFAULT_STRATEGY = 0, 211 } 212 /* compression strategy; see deflateInit2() below for details */ 213 214 enum 215 { 216 Z_BINARY = 0, 217 Z_TEXT = 1, 218 Z_UNKNOWN = 2, 219 220 Z_ASCII = Z_TEXT 221 } 222 /* Possible values of the data_type field for deflate() */ 223 224 enum 225 { 226 Z_DEFLATED = 8, 227 } 228 /* The deflate compression method (the only one supported in this version) */ 229 230 const int Z_NULL = 0; /* for initializing zalloc, zfree, opaque */ 231 232 /* basic functions */ 233 234 const(char)* zlibVersion(); 235 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 236 If the first character differs, the library code actually used is not 237 compatible with the zlib.h header file used by the application. This check 238 is automatically made by deflateInit and inflateInit. 239 */ 240 241 int deflateInit(z_streamp strm, int level) 242 { 243 return deflateInit_(strm, level, ZLIB_VERSION.ptr, z_stream.sizeof); 244 } 245 /* 246 Initializes the internal stream state for compression. The fields 247 zalloc, zfree and opaque must be initialized before by the caller. If 248 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 249 allocation functions. 250 251 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 252 1 gives best speed, 9 gives best compression, 0 gives no compression at all 253 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 254 requests a default compromise between speed and compression (currently 255 equivalent to level 6). 256 257 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 258 memory, Z_STREAM_ERROR if level is not a valid compression level, or 259 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 260 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 261 if there is no error message. deflateInit does not perform any compression: 262 this will be done by deflate(). 263 */ 264 265 266 int deflate(z_streamp strm, int flush); 267 /* 268 deflate compresses as much data as possible, and stops when the input 269 buffer becomes empty or the output buffer becomes full. It may introduce 270 some output latency (reading input without producing any output) except when 271 forced to flush. 272 273 The detailed semantics are as follows. deflate performs one or both of the 274 following actions: 275 276 - Compress more input starting at next_in and update next_in and avail_in 277 accordingly. If not all input can be processed (because there is not 278 enough room in the output buffer), next_in and avail_in are updated and 279 processing will resume at this point for the next call of deflate(). 280 281 - Generate more output starting at next_out and update next_out and avail_out 282 accordingly. This action is forced if the parameter flush is non zero. 283 Forcing flush frequently degrades the compression ratio, so this parameter 284 should be set only when necessary. Some output may be provided even if 285 flush is zero. 286 287 Before the call of deflate(), the application should ensure that at least 288 one of the actions is possible, by providing more input and/or consuming more 289 output, and updating avail_in or avail_out accordingly; avail_out should 290 never be zero before the call. The application can consume the compressed 291 output when it wants, for example when the output buffer is full (avail_out 292 == 0), or after each call of deflate(). If deflate returns Z_OK and with 293 zero avail_out, it must be called again after making room in the output 294 buffer because there might be more output pending. See deflatePending(), 295 which can be used if desired to determine whether or not there is more ouput 296 in that case. 297 298 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 299 decide how much data to accumulate before producing output, in order to 300 maximize compression. 301 302 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 303 flushed to the output buffer and the output is aligned on a byte boundary, so 304 that the decompressor can get all input data available so far. (In 305 particular avail_in is zero after the call if enough output space has been 306 provided before the call.) Flushing may degrade compression for some 307 compression algorithms and so it should be used only when necessary. This 308 completes the current deflate block and follows it with an empty stored block 309 that is three bits plus filler bits to the next byte, followed by four bytes 310 (00 00 ff ff). 311 312 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 313 output buffer, but the output is not aligned to a byte boundary. All of the 314 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 315 This completes the current deflate block and follows it with an empty fixed 316 codes block that is 10 bits long. This assures that enough bytes are output 317 in order for the decompressor to finish the block before the empty fixed 318 codes block. 319 320 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 321 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 322 seven bits of the current block are held to be written as the next byte after 323 the next deflate block is completed. In this case, the decompressor may not 324 be provided enough bits at this point in order to complete decompression of 325 the data provided so far to the compressor. It may need to wait for the next 326 block to be emitted. This is for advanced applications that need to control 327 the emission of deflate blocks. 328 329 If flush is set to Z_FULL_FLUSH, all output is flushed as with 330 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 331 restart from this point if previous compressed data has been damaged or if 332 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 333 compression. 334 335 If deflate returns with avail_out == 0, this function must be called again 336 with the same value of the flush parameter and more output space (updated 337 avail_out), until the flush is complete (deflate returns with non-zero 338 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 339 avail_out is greater than six to avoid repeated flush markers due to 340 avail_out == 0 on return. 341 342 If the parameter flush is set to Z_FINISH, pending input is processed, 343 pending output is flushed and deflate returns with Z_STREAM_END if there was 344 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 345 function must be called again with Z_FINISH and more output space (updated 346 avail_out) but no more input data, until it returns with Z_STREAM_END or an 347 error. After deflate has returned Z_STREAM_END, the only possible operations 348 on the stream are deflateReset or deflateEnd. 349 350 Z_FINISH can be used in the first deflate call after deflateInit if all the 351 compression is to be done in a single step. In order to complete in one 352 call, avail_out must be at least the value returned by deflateBound (see 353 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 354 output space is provided, deflate will not return Z_STREAM_END, and it must 355 be called again as described above. 356 357 deflate() sets strm->adler to the Adler-32 checksum of all input read 358 so far (that is, total_in bytes). If a gzip stream is being generated, then 359 strm->adler will be the CRC-32 checksum of the input read so far. (See 360 deflateInit2 below.) 361 362 deflate() may update strm->data_type if it can make a good guess about 363 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 364 considered binary. This field is only for information purposes and does not 365 affect the compression algorithm in any manner. 366 367 deflate() returns Z_OK if some progress has been made (more input 368 processed or more output produced), Z_STREAM_END if all input has been 369 consumed and all output has been produced (only when flush is set to 370 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 371 if next_in or next_out was Z_NULL or the state was inadvertently written over 372 by the application), or Z_BUF_ERROR if no progress is possible (for example 373 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 374 deflate() can be called again with more input and more output space to 375 continue compressing. 376 */ 377 378 379 int deflateEnd(z_streamp strm); 380 /* 381 All dynamically allocated data structures for this stream are freed. 382 This function discards any unprocessed input and does not flush any pending 383 output. 384 385 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 386 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 387 prematurely (some input or output was discarded). In the error case, msg 388 may be set but then points to a static string (which must not be 389 deallocated). 390 */ 391 392 393 int inflateInit(z_streamp strm) 394 { 395 return inflateInit_(strm, ZLIB_VERSION.ptr, z_stream.sizeof); 396 } 397 /* 398 Initializes the internal stream state for decompression. The fields 399 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 400 the caller. In the current version of inflate, the provided input is not 401 read or consumed. The allocation of a sliding window will be deferred to 402 the first call of inflate (if the decompression does not complete on the 403 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates 404 them to use default allocation functions. 405 406 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 407 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 408 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 409 invalid, such as a null pointer to the structure. msg is set to null if 410 there is no error message. inflateInit does not perform any decompression. 411 Actual decompression will be done by inflate(). So next_in, and avail_in, 412 next_out, and avail_out are unused and unchanged. The current 413 implementation of inflateInit() does not process any header information -- 414 that is deferred until inflate() is called. 415 */ 416 417 418 int inflate(z_streamp strm, int flush); 419 /* 420 inflate decompresses as much data as possible, and stops when the input 421 buffer becomes empty or the output buffer becomes full. It may introduce 422 some output latency (reading input without producing any output) except when 423 forced to flush. 424 425 The detailed semantics are as follows. inflate performs one or both of the 426 following actions: 427 428 - Decompress more input starting at next_in and update next_in and avail_in 429 accordingly. If not all input can be processed (because there is not 430 enough room in the output buffer), then next_in and avail_in are updated 431 accordingly, and processing will resume at this point for the next call of 432 inflate(). 433 434 - Generate more output starting at next_out and update next_out and avail_out 435 accordingly. inflate() provides as much output as possible, until there is 436 no more input data or no more space in the output buffer (see below about 437 the flush parameter). 438 439 Before the call of inflate(), the application should ensure that at least 440 one of the actions is possible, by providing more input and/or consuming more 441 output, and updating the next_* and avail_* values accordingly. If the 442 caller of inflate() does not provide both available input and available 443 output space, it is possible that there will be no progress made. The 444 application can consume the uncompressed output when it wants, for example 445 when the output buffer is full (avail_out == 0), or after each call of 446 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 447 called again after making room in the output buffer because there might be 448 more output pending. 449 450 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 451 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 452 output as possible to the output buffer. Z_BLOCK requests that inflate() 453 stop if and when it gets to the next deflate block boundary. When decoding 454 the zlib or gzip format, this will cause inflate() to return immediately 455 after the header and before the first block. When doing a raw inflate, 456 inflate() will go ahead and process the first block, and will return when it 457 gets to the end of that block, or when it runs out of data. 458 459 The Z_BLOCK option assists in appending to or combining deflate streams. 460 To assist in this, on return inflate() always sets strm->data_type to the 461 number of unused bits in the last byte taken from strm->next_in, plus 64 if 462 inflate() is currently decoding the last block in the deflate stream, plus 463 128 if inflate() returned immediately after decoding an end-of-block code or 464 decoding the complete header up to just before the first byte of the deflate 465 stream. The end-of-block will not be indicated until all of the uncompressed 466 data from that block has been written to strm->next_out. The number of 467 unused bits may in general be greater than seven, except when bit 7 of 468 data_type is set, in which case the number of unused bits will be less than 469 eight. data_type is set as noted here every time inflate() returns for all 470 flush options, and so can be used to determine the amount of currently 471 consumed input in bits. 472 473 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 474 end of each deflate block header is reached, before any actual data in that 475 block is decoded. This allows the caller to determine the length of the 476 deflate block header for later use in random access within a deflate block. 477 256 is added to the value of strm->data_type when inflate() returns 478 immediately after reaching the end of the deflate block header. 479 480 inflate() should normally be called until it returns Z_STREAM_END or an 481 error. However if all decompression is to be performed in a single step (a 482 single call of inflate), the parameter flush should be set to Z_FINISH. In 483 this case all pending input is processed and all pending output is flushed; 484 avail_out must be large enough to hold all of the uncompressed data for the 485 operation to complete. (The size of the uncompressed data may have been 486 saved by the compressor for this purpose.) The use of Z_FINISH is not 487 required to perform an inflation in one step. However it may be used to 488 inform inflate that a faster approach can be used for the single inflate() 489 call. Z_FINISH also informs inflate to not maintain a sliding window if the 490 stream completes, which reduces inflate's memory footprint. If the stream 491 does not complete, either because not all of the stream is provided or not 492 enough output space is provided, then a sliding window will be allocated and 493 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 494 been used. 495 496 In this implementation, inflate() always flushes as much output as 497 possible to the output buffer, and always uses the faster approach on the 498 first call. So the effects of the flush parameter in this implementation are 499 on the return value of inflate() as noted below, when inflate() returns early 500 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 501 memory for a sliding window when Z_FINISH is used. 502 503 If a preset dictionary is needed after this call (see inflateSetDictionary 504 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 505 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 506 strm->adler to the Adler-32 checksum of all output produced so far (that is, 507 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 508 below. At the end of the stream, inflate() checks that its computed Adler-32 509 checksum is equal to that saved by the compressor and returns Z_STREAM_END 510 only if the checksum is correct. 511 512 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 513 deflate data. The header type is detected automatically, if requested when 514 initializing with inflateInit2(). Any information contained in the gzip 515 header is not retained unless inflateGetHeader() is used. When processing 516 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 517 produced so far. The CRC-32 is checked against the gzip trailer, as is the 518 uncompressed length, modulo 2^32. 519 520 inflate() returns Z_OK if some progress has been made (more input processed 521 or more output produced), Z_STREAM_END if the end of the compressed data has 522 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 523 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 524 corrupted (input stream not conforming to the zlib format or incorrect check 525 value, in which case strm->msg points to a string with a more specific 526 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 527 next_in or next_out was Z_NULL, or the state was inadvertently written over 528 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 529 if no progress was possible or if there was not enough room in the output 530 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 531 inflate() can be called again with more input and more output space to 532 continue decompressing. If Z_DATA_ERROR is returned, the application may 533 then call inflateSync() to look for a good compression block if a partial 534 recovery of the data is to be attempted. 535 */ 536 537 538 int inflateEnd(z_streamp strm); 539 /* 540 All dynamically allocated data structures for this stream are freed. 541 This function discards any unprocessed input and does not flush any pending 542 output. 543 544 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 545 was inconsistent. 546 */ 547 548 /* Advanced functions */ 549 550 /* 551 The following functions are needed only in some special applications. 552 */ 553 554 int deflateInit2(z_streamp strm, 555 int level, 556 int method, 557 int windowBits, 558 int memLevel, 559 int strategy) 560 { 561 return deflateInit2_(strm, level, method, windowBits, memLevel, 562 strategy, ZLIB_VERSION.ptr, z_stream.sizeof); 563 } 564 /* 565 This is another version of deflateInit with more compression options. The 566 fields next_in, zalloc, zfree and opaque must be initialized before by the 567 caller. 568 569 The method parameter is the compression method. It must be Z_DEFLATED in 570 this version of the library. 571 572 The windowBits parameter is the base two logarithm of the window size 573 (the size of the history buffer). It should be in the range 8 .. 15 for this 574 version of the library. Larger values of this parameter result in better 575 compression at the expense of memory usage. The default value is 15 if 576 deflateInit is used instead. 577 578 For the current implementation of deflate(), a windowBits value of 8 (a 579 window size of 256 bytes) is not supported. As a result, a request for 8 580 will result in 9 (a 512-byte window). In that case, providing 8 to 581 inflateInit2() will result in an error when the zlib header with 9 is 582 checked against the initialization of inflate(). The remedy is to not use 8 583 with deflateInit2() with this initialization, or at least in that case use 9 584 with inflateInit2(). 585 586 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 587 determines the window size. deflate() will then generate raw deflate data 588 with no zlib header or trailer, and will not compute a check value. 589 590 windowBits can also be greater than 15 for optional gzip encoding. Add 591 16 to windowBits to write a simple gzip header and trailer around the 592 compressed data instead of a zlib wrapper. The gzip header will have no 593 file name, no extra data, no comment, no modification time (set to zero), no 594 header crc, and the operating system will be set to the appropriate value, 595 if the operating system was determined at compile time. If a gzip stream is 596 being written, strm->adler is a CRC-32 instead of an Adler-32. 597 598 For raw deflate or gzip encoding, a request for a 256-byte window is 599 rejected as invalid, since only the zlib header provides a means of 600 transmitting the window size to the decompressor. 601 602 The memLevel parameter specifies how much memory should be allocated 603 for the internal compression state. memLevel=1 uses minimum memory but is 604 slow and reduces compression ratio; memLevel=9 uses maximum memory for 605 optimal speed. The default value is 8. See zconf.h for total memory usage 606 as a function of windowBits and memLevel. 607 608 The strategy parameter is used to tune the compression algorithm. Use the 609 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 610 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 611 string match), or Z_RLE to limit match distances to one (run-length 612 encoding). Filtered data consists mostly of small values with a somewhat 613 random distribution. In this case, the compression algorithm is tuned to 614 compress them better. The effect of Z_FILTERED is to force more Huffman 615 coding and less string matching; it is somewhat intermediate between 616 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 617 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 618 strategy parameter only affects the compression ratio but not the 619 correctness of the compressed output even if it is not set appropriately. 620 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 621 decoder for special applications. 622 623 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 624 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 625 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 626 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 627 set to null if there is no error message. deflateInit2 does not perform any 628 compression: this will be done by deflate(). 629 */ 630 631 int deflateSetDictionary(z_streamp strm, const(ubyte)* dictionary, uint dictLength); 632 /* 633 Initializes the compression dictionary from the given byte sequence 634 without producing any compressed output. When using the zlib format, this 635 function must be called immediately after deflateInit, deflateInit2 or 636 deflateReset, and before any call of deflate. When doing raw deflate, this 637 function must be called either before any call of deflate, or immediately 638 after the completion of a deflate block, i.e. after all input has been 639 consumed and all output has been delivered when using any of the flush 640 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 641 compressor and decompressor must use exactly the same dictionary (see 642 inflateSetDictionary). 643 644 The dictionary should consist of strings (byte sequences) that are likely 645 to be encountered later in the data to be compressed, with the most commonly 646 used strings preferably put towards the end of the dictionary. Using a 647 dictionary is most useful when the data to be compressed is short and can be 648 predicted with good accuracy; the data can then be compressed better than 649 with the default empty dictionary. 650 651 Depending on the size of the compression data structures selected by 652 deflateInit or deflateInit2, a part of the dictionary may in effect be 653 discarded, for example if the dictionary is larger than the window size 654 provided in deflateInit or deflateInit2. Thus the strings most likely to be 655 useful should be put at the end of the dictionary, not at the front. In 656 addition, the current implementation of deflate will use at most the window 657 size minus 262 bytes of the provided dictionary. 658 659 Upon return of this function, strm->adler is set to the Adler-32 value 660 of the dictionary; the decompressor may later use this value to determine 661 which dictionary has been used by the compressor. (The Adler-32 value 662 applies to the whole dictionary even if only a subset of the dictionary is 663 actually used by the compressor.) If a raw deflate was requested, then the 664 Adler-32 value is not computed and strm->adler is not set. 665 666 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 667 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 668 inconsistent (for example if deflate has already been called for this stream 669 or if not at a block boundary for raw deflate). deflateSetDictionary does 670 not perform any compression: this will be done by deflate(). 671 */ 672 673 int deflateGetDictionary(z_streamp strm, ubyte *dictionary, uint dictLength); 674 /* 675 Returns the sliding dictionary being maintained by deflate. dictLength is 676 set to the number of bytes in the dictionary, and that many bytes are copied 677 to dictionary. dictionary must have enough space, where 32768 bytes is 678 always enough. If deflateGetDictionary() is called with dictionary equal to 679 Z_NULL, then only the dictionary length is returned, and nothing is copied. 680 Similary, if dictLength is Z_NULL, then it is not set. 681 682 deflateGetDictionary() may return a length less than the window size, even 683 when more than the window size in input has been provided. It may return up 684 to 258 bytes less in that case, due to how zlib's implementation of deflate 685 manages the sliding window and lookahead for matches, where matches can be 686 up to 258 bytes long. If the application needs the last window-size bytes of 687 input, then that would need to be saved by the application outside of zlib. 688 689 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 690 stream state is inconsistent. 691 */ 692 693 int deflateCopy(z_streamp dest, z_streamp source); 694 /* 695 Sets the destination stream as a complete copy of the source stream. 696 697 This function can be useful when several compression strategies will be 698 tried, for example when there are several ways of pre-processing the input 699 data with a filter. The streams that will be discarded should then be freed 700 by calling deflateEnd. Note that deflateCopy duplicates the internal 701 compression state which can be quite large, so this strategy is slow and can 702 consume lots of memory. 703 704 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 705 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 706 (such as zalloc being Z_NULL). msg is left unchanged in both source and 707 destination. 708 */ 709 710 int deflateReset(z_streamp strm); 711 /* 712 This function is equivalent to deflateEnd followed by deflateInit, but 713 does not free and reallocate the internal compression state. The stream 714 will leave the compression level and any other attributes that may have been 715 set unchanged. 716 717 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 718 stream state was inconsistent (such as zalloc or state being Z_NULL). 719 */ 720 721 int deflateParams(z_streamp strm, int level, int strategy); 722 /* 723 Dynamically update the compression level and compression strategy. The 724 interpretation of level and strategy is as in deflateInit2(). This can be 725 used to switch between compression and straight copy of the input data, or 726 to switch to a different kind of input data requiring a different strategy. 727 If the compression approach (which is a function of the level) or the 728 strategy is changed, and if any input has been consumed in a previous 729 deflate() call, then the input available so far is compressed with the old 730 level and strategy using deflate(strm, Z_BLOCK). There are three approaches 731 for the compression levels 0, 1 .. 3, and 4 .. 9 respectively. The new level 732 and strategy will take effect at the next call of deflate(). 733 734 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 735 not have enough output space to complete, then the parameter change will not 736 take effect. In this case, deflateParams() can be called again with the 737 same parameters and more output space to try again. 738 739 In order to assure a change in the parameters on the first try, the 740 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 741 request until strm.avail_out is not zero, before calling deflateParams(). 742 Then no more input data should be provided before the deflateParams() call. 743 If this is done, the old level and strategy will be applied to the data 744 compressed before deflateParams(), and the new level and strategy will be 745 applied to the the data compressed after deflateParams(). 746 747 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 748 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 749 there was not enough output space to complete the compression of the 750 available input data before a change in the strategy or approach. Note that 751 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 752 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 753 retried with more output space. 754 */ 755 756 int deflateTune(z_streamp strm, int good_length, int max_lazy, int nice_length, 757 int max_chain); 758 /* 759 Fine tune deflate's internal compression parameters. This should only be 760 used by someone who understands the algorithm used by zlib's deflate for 761 searching for the best matching string, and even then only by the most 762 fanatic optimizer trying to squeeze out the last compressed bit for their 763 specific input data. Read the deflate.c source code for the meaning of the 764 max_lazy, good_length, nice_length, and max_chain parameters. 765 766 deflateTune() can be called after deflateInit() or deflateInit2(), and 767 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 768 */ 769 770 size_t deflateBound(z_streamp strm, size_t sourceLen); 771 /* 772 deflateBound() returns an upper bound on the compressed size after 773 deflation of sourceLen bytes. It must be called after deflateInit() or 774 deflateInit2(), and after deflateSetHeader(), if used. This would be used 775 to allocate an output buffer for deflation in a single pass, and so would be 776 called before deflate(). If that first deflate() call is provided the 777 sourceLen input bytes, an output buffer allocated to the size returned by 778 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 779 to return Z_STREAM_END. Note that it is possible for the compressed size to 780 be larger than the value returned by deflateBound() if flush options other 781 than Z_FINISH or Z_NO_FLUSH are used. 782 */ 783 784 int deflatePending(z_streamp strm, uint* pending, int* bits); 785 /* 786 deflatePending() returns the number of bytes and bits of output that have 787 been generated, but not yet provided in the available output. The bytes not 788 provided would be due to the available output space having being consumed. 789 The number of bits of output not provided are between 0 and 7, where they 790 await more bits to join them in order to fill out a full byte. If pending 791 or bits are Z_NULL, then those values are not set. 792 793 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 794 stream state was inconsistent. 795 */ 796 797 int deflatePrime(z_streamp strm, int bits, int value); 798 /* 799 deflatePrime() inserts bits in the deflate output stream. The intent 800 is that this function is used to start off the deflate output with the bits 801 leftover from a previous deflate stream when appending to it. As such, this 802 function can only be used for raw deflate, and must be used before the first 803 deflate() call after a deflateInit2() or deflateReset(). bits must be less 804 than or equal to 16, and that many of the least significant bits of value 805 will be inserted in the output. 806 807 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 808 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 809 source stream state was inconsistent. 810 */ 811 812 int deflateSetHeader(z_streamp strm, gz_headerp head); 813 /* 814 deflateSetHeader() provides gzip header information for when a gzip 815 stream is requested by deflateInit2(). deflateSetHeader() may be called 816 after deflateInit2() or deflateReset() and before the first call of 817 deflate(). The text, time, os, extra field, name, and comment information 818 in the provided gz_header structure are written to the gzip header (xflag is 819 ignored -- the extra flags are set according to the compression level). The 820 caller must assure that, if not Z_NULL, name and comment are terminated with 821 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 822 available there. If hcrc is true, a gzip header crc is included. Note that 823 the current versions of the command-line version of gzip (up through version 824 1.3.x) do not support header crc's, and will report that it is a "multi-part 825 gzip file" and give up. 826 827 If deflateSetHeader is not used, the default gzip header has text false, 828 the time set to zero, and os set to 255, with no extra, name, or comment 829 fields. The gzip header is returned to the default state by deflateReset(). 830 831 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 832 stream state was inconsistent. 833 */ 834 835 int inflateInit2(z_streamp strm, int windowBits) 836 { 837 return inflateInit2_(strm, windowBits, ZLIB_VERSION.ptr, z_stream.sizeof); 838 } 839 /* 840 This is another version of inflateInit with an extra parameter. The 841 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 842 before by the caller. 843 844 The windowBits parameter is the base two logarithm of the maximum window 845 size (the size of the history buffer). It should be in the range 8 .. 15 for 846 this version of the library. The default value is 15 if inflateInit is used 847 instead. windowBits must be greater than or equal to the windowBits value 848 provided to deflateInit2() while compressing, or it must be equal to 15 if 849 deflateInit2() was not used. If a compressed stream with a larger window 850 size is given as input, inflate() will return with the error code 851 Z_DATA_ERROR instead of trying to allocate a larger window. 852 853 windowBits can also be zero to request that inflate use the window size in 854 the zlib header of the compressed stream. 855 856 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 857 determines the window size. inflate() will then process raw deflate data, 858 not looking for a zlib or gzip header, not generating a check value, and not 859 looking for any check values for comparison at the end of the stream. This 860 is for use with other formats that use the deflate compressed data format 861 such as zip. Those formats provide their own check values. If a custom 862 format is developed using the raw deflate format for compressed data, it is 863 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 864 the uncompressed data as is done in the zlib, gzip, and zip formats. For 865 most applications, the zlib format should be used as is. Note that comments 866 above on the use in deflateInit2() applies to the magnitude of windowBits. 867 868 windowBits can also be greater than 15 for optional gzip decoding. Add 869 32 to windowBits to enable zlib and gzip decoding with automatic header 870 detection, or add 16 to decode only the gzip format (the zlib format will 871 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 872 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 873 below), inflate() will not automatically decode concatenated gzip streams. 874 inflate() will return Z_STREAM_END at the end of the gzip stream. The state 875 would need to be reset to continue decoding a subsequent gzip stream. 876 877 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 878 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 879 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 880 invalid, such as a null pointer to the structure. msg is set to null if 881 there is no error message. inflateInit2 does not perform any decompression 882 apart from possibly reading the zlib header if present: actual decompression 883 will be done by inflate(). (So next_in and avail_in may be modified, but 884 next_out and avail_out are unused and unchanged.) The current implementation 885 of inflateInit2() does not process any header information -- that is 886 deferred until inflate() is called. 887 */ 888 889 int inflateSetDictionary(z_streamp strm, const(ubyte)* dictionary, uint dictLength); 890 /* 891 Initializes the decompression dictionary from the given uncompressed byte 892 sequence. This function must be called immediately after a call of inflate, 893 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 894 can be determined from the Adler-32 value returned by that call of inflate. 895 The compressor and decompressor must use exactly the same dictionary (see 896 deflateSetDictionary). For raw inflate, this function can be called at any 897 time to set the dictionary. If the provided dictionary is smaller than the 898 window and there is already data in the window, then the provided dictionary 899 will amend what's there. The application must insure that the dictionary 900 that was used for compression is provided. 901 902 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 903 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 904 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 905 expected one (incorrect Adler-32 value). inflateSetDictionary does not 906 perform any decompression: this will be done by subsequent calls of 907 inflate(). 908 */ 909 910 int inflateGetDictionary(z_streamp strm, ubyte* dictionary, uint* dictLength); 911 /* 912 Returns the sliding dictionary being maintained by inflate. dictLength is 913 set to the number of bytes in the dictionary, and that many bytes are copied 914 to dictionary. dictionary must have enough space, where 32768 bytes is 915 always enough. If inflateGetDictionary() is called with dictionary equal to 916 Z_NULL, then only the dictionary length is returned, and nothing is copied. 917 Similary, if dictLength is Z_NULL, then it is not set. 918 919 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 920 stream state is inconsistent. 921 */ 922 923 int inflateSync(z_streamp strm); 924 /* 925 Skips invalid compressed data until a possible full flush point (see above 926 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 927 available input is skipped. No output is provided. 928 929 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 930 All full flush points have this pattern, but not all occurrences of this 931 pattern are full flush points. 932 933 inflateSync returns Z_OK if a possible full flush point has been found, 934 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 935 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 936 In the success case, the application may save the current current value of 937 total_in which indicates where valid compressed data was found. In the 938 error case, the application may repeatedly call inflateSync, providing more 939 input each time, until success or end of the input data. 940 */ 941 942 int inflateCopy(z_streamp dest, z_streamp source); 943 /* 944 Sets the destination stream as a complete copy of the source stream. 945 946 This function can be useful when randomly accessing a large stream. The 947 first pass through the stream can periodically record the inflate state, 948 allowing restarting inflate at those points when randomly accessing the 949 stream. 950 951 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 952 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 953 (such as zalloc being Z_NULL). msg is left unchanged in both source and 954 destination. 955 */ 956 957 int inflateReset(z_streamp strm); 958 /* 959 This function is equivalent to inflateEnd followed by inflateInit, 960 but does not free and reallocate the internal decompression state. The 961 stream will keep attributes that may have been set by inflateInit2. 962 963 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 964 stream state was inconsistent (such as zalloc or state being Z_NULL). 965 */ 966 967 int inflateReset2(z_streamp strm, int windowBits); 968 /* 969 This function is the same as inflateReset, but it also permits changing 970 the wrap and window size requests. The windowBits parameter is interpreted 971 the same as it is for inflateInit2. If the window size is changed, then the 972 memory allocated for the window is freed, and the window will be reallocated 973 by inflate() if needed. 974 975 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 976 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 977 the windowBits parameter is invalid. 978 */ 979 980 int inflatePrime(z_streamp strm, int bits, int value); 981 /* 982 This function inserts bits in the inflate input stream. The intent is 983 that this function is used to start inflating at a bit position in the 984 middle of a byte. The provided bits will be used before any bytes are used 985 from next_in. This function should only be used with raw inflate, and 986 should be used before the first inflate() call after inflateInit2() or 987 inflateReset(). bits must be less than or equal to 16, and that many of the 988 least significant bits of value will be inserted in the input. 989 990 If bits is negative, then the input stream bit buffer is emptied. Then 991 inflatePrime() can be called again to put bits in the buffer. This is used 992 to clear out bits leftover after feeding inflate a block description prior 993 to feeding inflate codes. 994 995 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 996 stream state was inconsistent. 997 */ 998 999 c_long inflateMark(z_streamp strm); 1000 /* 1001 This function returns two values, one in the lower 16 bits of the return 1002 value, and the other in the remaining upper bits, obtained by shifting the 1003 return value down 16 bits. If the upper value is -1 and the lower value is 1004 zero, then inflate() is currently decoding information outside of a block. 1005 If the upper value is -1 and the lower value is non-zero, then inflate is in 1006 the middle of a stored block, with the lower value equaling the number of 1007 bytes from the input remaining to copy. If the upper value is not -1, then 1008 it is the number of bits back from the current bit position in the input of 1009 the code (literal or length/distance pair) currently being processed. In 1010 that case the lower value is the number of bytes already emitted for that 1011 code. 1012 1013 A code is being processed if inflate is waiting for more input to complete 1014 decoding of the code, or if it has completed decoding but is waiting for 1015 more output space to write the literal or match data. 1016 1017 inflateMark() is used to mark locations in the input data for random 1018 access, which may be at bit positions, and to note those cases where the 1019 output of a code may span boundaries of random access blocks. The current 1020 location in the input stream can be determined from avail_in and data_type 1021 as noted in the description for the Z_BLOCK flush parameter for inflate. 1022 1023 inflateMark returns the value noted above, or -65536 if the provided 1024 source stream state was inconsistent. 1025 */ 1026 1027 int inflateGetHeader(z_streamp strm, gz_headerp head); 1028 /* 1029 inflateGetHeader() requests that gzip header information be stored in the 1030 provided gz_header structure. inflateGetHeader() may be called after 1031 inflateInit2() or inflateReset(), and before the first call of inflate(). 1032 As inflate() processes the gzip stream, head->done is zero until the header 1033 is completed, at which time head->done is set to one. If a zlib stream is 1034 being decoded, then head->done is set to -1 to indicate that there will be 1035 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1036 used to force inflate() to return immediately after header processing is 1037 complete and before any actual data is decompressed. 1038 1039 The text, time, xflags, and os fields are filled in with the gzip header 1040 contents. hcrc is set to true if there is a header CRC. (The header CRC 1041 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 1042 contains the maximum number of bytes to write to extra. Once done is true, 1043 extra_len contains the actual extra field length, and extra contains the 1044 extra field, or that field truncated if extra_max is less than extra_len. 1045 If name is not Z_NULL, then up to name_max characters are written there, 1046 terminated with a zero unless the length is greater than name_max. If 1047 comment is not Z_NULL, then up to comm_max characters are written there, 1048 terminated with a zero unless the length is greater than comm_max. When any 1049 of extra, name, or comment are not Z_NULL and the respective field is not 1050 present in the header, then that field is set to Z_NULL to signal its 1051 absence. This allows the use of deflateSetHeader() with the returned 1052 structure to duplicate the header. However if those fields are set to 1053 allocated memory, then the application will need to save those pointers 1054 elsewhere so that they can be eventually freed. 1055 1056 If inflateGetHeader is not used, then the header information is simply 1057 discarded. The header is always checked for validity, including the header 1058 CRC if present. inflateReset() will reset the process to discard the header 1059 information. The application would need to call inflateGetHeader() again to 1060 retrieve the header from the next gzip stream. 1061 1062 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1063 stream state was inconsistent. 1064 */ 1065 1066 1067 int inflateBackInit(z_stream* strm, int windowBits, ubyte* window) 1068 { 1069 return inflateBackInit_(strm, windowBits, window, ZLIB_VERSION.ptr, z_stream.sizeof); 1070 } 1071 /* 1072 Initialize the internal stream state for decompression using inflateBack() 1073 calls. The fields zalloc, zfree and opaque in strm must be initialized 1074 before the call. If zalloc and zfree are Z_NULL, then the default library- 1075 derived memory allocation routines are used. windowBits is the base two 1076 logarithm of the window size, in the range 8 .. 15. window is a caller 1077 supplied buffer of that size. Except for special applications where it is 1078 assured that deflate was used with small window sizes, windowBits must be 15 1079 and a 32K byte window must be supplied to be able to decompress general 1080 deflate streams. 1081 1082 See inflateBack() for the usage of these routines. 1083 1084 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1085 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1086 allocated, or Z_VERSION_ERROR if the version of the library does not match 1087 the version of the header file. 1088 */ 1089 1090 alias in_func = uint function(void*, ubyte**); 1091 alias out_func = int function(void*, ubyte*, uint); 1092 1093 int inflateBack(z_stream* strm, 1094 in_func f_in, 1095 void* in_desc, 1096 out_func f_out, 1097 void* out_desc); 1098 /* 1099 inflateBack() does a raw inflate with a single call using a call-back 1100 interface for input and output. This is potentially more efficient than 1101 inflate() for file i/o applications, in that it avoids copying between the 1102 output and the sliding window by simply making the window itself the output 1103 buffer. inflate() can be faster on modern CPUs when used with large 1104 buffers. inflateBack() trusts the application to not change the output 1105 buffer passed by the output function, at least until inflateBack() returns. 1106 1107 inflateBackInit() must be called first to allocate the internal state 1108 and to initialize the state with the user-provided window buffer. 1109 inflateBack() may then be used multiple times to inflate a complete, raw 1110 deflate stream with each call. inflateBackEnd() is then called to free the 1111 allocated state. 1112 1113 A raw deflate stream is one with no zlib or gzip header or trailer. 1114 This routine would normally be used in a utility that reads zip or gzip 1115 files and writes out uncompressed files. The utility would decode the 1116 header and process the trailer on its own, hence this routine expects only 1117 the raw deflate stream to decompress. This is different from the default 1118 behavior of inflate(), which expects a zlib header and trailer around the 1119 deflate stream. 1120 1121 inflateBack() uses two subroutines supplied by the caller that are then 1122 called by inflateBack() for input and output. inflateBack() calls those 1123 routines until it reads a complete deflate stream and writes out all of the 1124 uncompressed data, or until it encounters an error. The function's 1125 parameters and return types are defined above in the in_func and out_func 1126 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1127 number of bytes of provided input, and a pointer to that input in buf. If 1128 there is no input available, in() must return zero -- buf is ignored in that 1129 case -- and inflateBack() will return a buffer error. inflateBack() will 1130 call out(out_desc, buf, len) to write the uncompressed data buf[0 .. len-1]. 1131 out() should return zero on success, or non-zero on failure. If out() 1132 returns non-zero, inflateBack() will return with an error. Neither in() nor 1133 out() are permitted to change the contents of the window provided to 1134 inflateBackInit(), which is also the buffer that out() uses to write from. 1135 The length written by out() will be at most the window size. Any non-zero 1136 amount of input may be provided by in(). 1137 1138 For convenience, inflateBack() can be provided input on the first call by 1139 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1140 in() will be called. Therefore strm->next_in must be initialized before 1141 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1142 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1143 must also be initialized, and then if strm->avail_in is not zero, input will 1144 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1145 1146 The in_desc and out_desc parameters of inflateBack() is passed as the 1147 first parameter of in() and out() respectively when they are called. These 1148 descriptors can be optionally used to pass any information that the caller- 1149 supplied in() and out() functions need to do their job. 1150 1151 On return, inflateBack() will set strm->next_in and strm->avail_in to 1152 pass back any unused input that was provided by the last in() call. The 1153 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1154 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1155 in the deflate stream (in which case strm->msg is set to indicate the nature 1156 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1157 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1158 using strm->next_in which will be Z_NULL only if in() returned an error. If 1159 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1160 non-zero. (in() will always be called before out(), so strm->next_in is 1161 assured to be defined if out() returns non-zero.) Note that inflateBack() 1162 cannot return Z_OK. 1163 */ 1164 1165 int inflateBackEnd(z_stream* strm); 1166 /* 1167 All memory allocated by inflateBackInit() is freed. 1168 1169 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1170 state was inconsistent. 1171 */ 1172 1173 uint zlibCompileFlags(); 1174 /* Return flags indicating compile-time options. 1175 1176 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1177 1.0: size of uInt 1178 3.2: size of uLong 1179 5.4: size of voidpf (pointer) 1180 7.6: size of z_off_t 1181 1182 Compiler, assembler, and debug options: 1183 8: ZLIB_DEBUG 1184 9: ASMV or ASMINF -- use ASM code 1185 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1186 11: 0 (reserved) 1187 1188 One-time table building (smaller code, but not thread-safe if true): 1189 12: BUILDFIXED -- build static block decoding tables when needed 1190 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1191 14,15: 0 (reserved) 1192 1193 Library content (indicates missing functionality): 1194 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1195 deflate code when not needed) 1196 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1197 and decode gzip streams (to avoid linking crc code) 1198 18-19: 0 (reserved) 1199 1200 Operation variations (changes in library functionality): 1201 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1202 21: FASTEST -- deflate algorithm with only one, lowest compression level 1203 22,23: 0 (reserved) 1204 1205 The sprintf variant used by gzprintf (zero is best): 1206 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1207 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1208 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1209 1210 Remainder: 1211 27-31: 0 (reserved) 1212 */ 1213 1214 /* utility functions */ 1215 1216 /* 1217 The following utility functions are implemented on top of the basic 1218 stream-oriented functions. To simplify the interface, some default options 1219 are assumed (compression level and memory usage, standard memory allocation 1220 functions). The source code of these utility functions can be modified if 1221 you need special options. 1222 */ 1223 1224 int compress(ubyte* dest, 1225 size_t* destLen, 1226 const(ubyte)* source, 1227 size_t sourceLen); 1228 /* 1229 Compresses the source buffer into the destination buffer. sourceLen is 1230 the byte length of the source buffer. Upon entry, destLen is the total size 1231 of the 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. compress() is equivalent to compress2() with a level 1234 parameter of Z_DEFAULT_COMPRESSION. 1235 1236 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1237 enough memory, Z_BUF_ERROR if there was not enough room in the output 1238 buffer. 1239 */ 1240 1241 int compress2(ubyte* dest, 1242 size_t* destLen, 1243 const(ubyte)* source, 1244 size_t sourceLen, 1245 int level); 1246 /* 1247 Compresses the source buffer into the destination buffer. The level 1248 parameter has the same meaning as in deflateInit. sourceLen is the byte 1249 length of the source buffer. Upon entry, destLen is the total size of the 1250 destination buffer, which must be at least the value returned by 1251 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1252 compressed data. 1253 1254 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1255 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1256 Z_STREAM_ERROR if the level parameter is invalid. 1257 */ 1258 1259 size_t compressBound(size_t sourceLen); 1260 /* 1261 compressBound() returns an upper bound on the compressed size after 1262 compress() or compress2() on sourceLen bytes. It would be used before a 1263 compress() or compress2() call to allocate the destination buffer. 1264 */ 1265 1266 int uncompress(ubyte* dest, 1267 size_t* destLen, 1268 const(ubyte)* source, 1269 size_t sourceLen); 1270 /* 1271 Decompresses the source buffer into the destination buffer. sourceLen is 1272 the byte length of the source buffer. Upon entry, destLen is the total size 1273 of the destination buffer, which must be large enough to hold the entire 1274 uncompressed data. (The size of the uncompressed data must have been saved 1275 previously by the compressor and transmitted to the decompressor by some 1276 mechanism outside the scope of this compression library.) Upon exit, destLen 1277 is the actual size of the uncompressed data. 1278 1279 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1280 enough memory, Z_BUF_ERROR if there was not enough room in the output 1281 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1282 the case where there is not enough room, uncompress() will fill the output 1283 buffer with the uncompressed data up to that point. 1284 */ 1285 1286 int uncompress2(ubyte* dest, 1287 size_t* destLen, 1288 const(ubyte)* source, 1289 size_t* sourceLen); 1290 /* 1291 Same as uncompress, except that sourceLen is a pointer, where the 1292 length of the source is *sourceLen. On return, *sourceLen is the number of 1293 source bytes consumed. 1294 */ 1295 1296 /* gzip file access functions */ 1297 1298 /* 1299 This library supports reading and writing files in gzip (.gz) format with 1300 an interface similar to that of stdio, using the functions that start with 1301 "gz". The gzip format is different from the zlib format. gzip is a gzip 1302 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1303 */ 1304 1305 alias gzFile = void*; 1306 alias z_off_t = int; // file offset 1307 alias z_size_t = size_t; 1308 1309 gzFile gzopen(const(char)* path, const(char)* mode); 1310 /* 1311 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 1312 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 1313 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 1314 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 1315 for fixed code compression as in "wb9F". (See the description of 1316 deflateInit2 for more information about the strategy parameter.) 'T' will 1317 request transparent writing or appending with no compression and not using 1318 the gzip format. 1319 1320 "a" can be used instead of "w" to request that the gzip stream that will 1321 be written be appended to the file. "+" will result in an error, since 1322 reading and writing to the same gzip file is not supported. The addition of 1323 "x" when writing will create the file exclusively, which fails if the file 1324 already exists. On systems that support it, the addition of "e" when 1325 reading or writing will set the flag to close the file on an execve() call. 1326 1327 These functions, as well as gzip, will read and decode a sequence of gzip 1328 streams in a file. The append function of gzopen() can be used to create 1329 such a file. (Also see gzflush() for another way to do this.) When 1330 appending, gzopen does not test whether the file begins with a gzip stream, 1331 nor does it look for the end of the gzip streams to begin appending. gzopen 1332 will simply append a gzip stream to the existing file. 1333 1334 gzopen can be used to read a file which is not in gzip format; in this 1335 case gzread will directly read from the file without decompression. When 1336 reading, this will be detected automatically by looking for the magic two- 1337 byte gzip header. 1338 1339 gzopen returns NULL if the file could not be opened, if there was 1340 insufficient memory to allocate the gzFile state, or if an invalid mode was 1341 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1342 errno can be checked to determine if the reason gzopen failed was that the 1343 file could not be opened. 1344 */ 1345 1346 gzFile gzdopen(int fd, const(char)* mode); 1347 /* 1348 gzdopen associates a gzFile with the file descriptor fd. File descriptors 1349 are obtained from calls like open, dup, creat, pipe or fileno (if the file 1350 has been previously opened with fopen). The mode parameter is as in gzopen. 1351 1352 The next call of gzclose on the returned gzFile will also close the file 1353 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1354 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1355 mode);. The duplicated descriptor should be saved to avoid a leak, since 1356 gzdopen does not close fd if it fails. If you are using fileno() to get the 1357 file descriptor from a FILE *, then you will have to use dup() to avoid 1358 double-close()ing the file descriptor. Both gzclose() and fclose() will 1359 close the associated file descriptor, so they need to have different file 1360 descriptors. 1361 1362 gzdopen returns NULL if there was insufficient memory to allocate the 1363 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1364 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1365 used until the next gz* read, write, seek, or close operation, so gzdopen 1366 will not detect if fd is invalid (unless fd is -1). 1367 */ 1368 1369 int gzbuffer(gzFile file, uint size); 1370 /* 1371 Set the internal buffer size used by this library's functions. The 1372 default buffer size is 8192 bytes. This function must be called after 1373 gzopen() or gzdopen(), and before any other calls that read or write the 1374 file. The buffer memory allocation is always deferred to the first read or 1375 write. Three times that size in buffer space is allocated. A larger buffer 1376 size of, for example, 64K or 128K bytes will noticeably increase the speed 1377 of decompression (reading). 1378 1379 The new buffer size also affects the maximum length for gzprintf(). 1380 1381 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1382 too late. 1383 */ 1384 1385 int gzsetparams(gzFile file, int level, int strategy); 1386 /* 1387 Dynamically update the compression level or strategy. See the description 1388 of deflateInit2 for the meaning of these parameters. Previously provided 1389 data is flushed before the parameter change. 1390 1391 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1392 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1393 or Z_MEM_ERROR if there is a memory allocation error. 1394 */ 1395 1396 int gzread(gzFile file, void* buf, uint len); 1397 /* 1398 Reads the given number of uncompressed bytes from the compressed file. If 1399 the input file is not in gzip format, gzread copies the given number of 1400 bytes into the buffer directly from the file. 1401 1402 After reaching the end of a gzip stream in the input, gzread will continue 1403 to read, looking for another gzip stream. Any number of gzip streams may be 1404 concatenated in the input file, and will all be decompressed by gzread(). 1405 If something other than a gzip stream is encountered after a gzip stream, 1406 that remaining trailing garbage is ignored (and no error is returned). 1407 1408 gzread can be used to read a gzip file that is being concurrently written. 1409 Upon reaching the end of the input, gzread will return with the available 1410 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1411 gzclearerr can be used to clear the end of file indicator in order to permit 1412 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1413 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1414 middle of a gzip stream. Note that gzread does not return -1 in the event 1415 of an incomplete gzip stream. This error is deferred until gzclose(), which 1416 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1417 stream. Alternatively, gzerror can be used before gzclose to detect this 1418 case. 1419 1420 gzread returns the number of uncompressed bytes actually read, less than 1421 len for end of file, or -1 for error. If len is too large to fit in an int, 1422 then nothing is read, -1 is returned, and the error state is set to 1423 Z_STREAM_ERROR. 1424 */ 1425 1426 z_size_t gzfread(void* buf, z_size_t size, z_size_t nitems, gzFile file); 1427 /* 1428 Read up to nitems items of size size from file to buf, otherwise operating 1429 as gzread() does. This duplicates the interface of stdio's fread(), with 1430 size_t request and return types. If the library defines size_t, then 1431 z_size_t is identical to size_t. If not, then z_size_t is an unsigned 1432 integer type that can contain a pointer. 1433 1434 gzfread() returns the number of full items read of size size, or zero if 1435 the end of the file was reached and a full item could not be read, or if 1436 there was an error. gzerror() must be consulted if zero is returned in 1437 order to determine if there was an error. If the multiplication of size and 1438 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing 1439 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1440 1441 In the event that the end of file is reached and only a partial item is 1442 available at the end, i.e. the remaining uncompressed data length is not a 1443 multiple of size, then the final partial item is nevetheless read into buf 1444 and the end-of-file flag is set. The length of the partial item read is not 1445 provided, but could be inferred from the result of gztell(). This behavior 1446 is the same as the behavior of fread() implementations in common libraries, 1447 but it prevents the direct use of gzfread() to read a concurrently written 1448 file, reseting and retrying on end-of-file, when size is not 1. 1449 */ 1450 1451 int gzwrite(gzFile file, void* buf, uint len); 1452 /* 1453 Writes the given number of uncompressed bytes into the compressed file. 1454 gzwrite returns the number of uncompressed bytes written or 0 in case of 1455 error. 1456 */ 1457 1458 z_size_t gzfwrite(void* buf, z_size_t size, z_size_t nitems, gzFile file); 1459 /* 1460 gzfwrite() writes nitems items of size size from buf to file, duplicating 1461 the interface of stdio's fwrite(), with size_t request and return types. If 1462 the library defines size_t, then z_size_t is identical to size_t. If not, 1463 then z_size_t is an unsigned integer type that can contain a pointer. 1464 1465 gzfwrite() returns the number of full items written of size size, or zero 1466 if there was an error. If the multiplication of size and nitems overflows, 1467 i.e. the product does not fit in a z_size_t, then nothing is written, zero 1468 is returned, and the error state is set to Z_STREAM_ERROR. 1469 */ 1470 1471 int gzprintf(gzFile file, const(char)* format, ...); 1472 /* 1473 Converts, formats, and writes the arguments to the compressed file under 1474 control of the format string, as in fprintf. gzprintf returns the number of 1475 uncompressed bytes actually written, or a negative zlib error code in case 1476 of error. The number of uncompressed bytes written is limited to 8191, or 1477 one less than the buffer size given to gzbuffer(). The caller should assure 1478 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1479 return an error (0) with nothing written. In this case, there may also be a 1480 buffer overflow with unpredictable consequences, which is possible only if 1481 zlib was compiled with the insecure functions sprintf() or vsprintf() 1482 because the secure snprintf() or vsnprintf() functions were not available. 1483 This can be determined using zlibCompileFlags(). 1484 */ 1485 1486 int gzputs(gzFile file, const(char)* s); 1487 /* 1488 Writes the given null-terminated string to the compressed file, excluding 1489 the terminating null character. 1490 1491 gzputs returns the number of characters written, or -1 in case of error. 1492 */ 1493 1494 const(char)* gzgets(gzFile file, const(char)* buf, int len); 1495 /* 1496 Reads bytes from the compressed file until len-1 characters are read, or a 1497 newline character is read and transferred to buf, or an end-of-file 1498 condition is encountered. If any characters are read or if len == 1, the 1499 string is terminated with a null character. If no characters are read due 1500 to an end-of-file or len < 1, then the buffer is left untouched. 1501 1502 gzgets returns buf which is a null-terminated string, or it returns NULL 1503 for end-of-file or in case of error. If there was an error, the contents at 1504 buf are indeterminate. 1505 */ 1506 1507 int gzputc(gzFile file, int c); 1508 /* 1509 Writes c, converted to an unsigned char, into the compressed file. gzputc 1510 returns the value that was written, or -1 in case of error. 1511 */ 1512 1513 int gzgetc(gzFile file); 1514 /* 1515 Reads one byte from the compressed file. gzgetc returns this byte or -1 1516 in case of end of file or error. This is implemented as a macro for speed. 1517 As such, it does not do all of the checking the other functions do. I.e. 1518 it does not check to see if file is NULL, nor whether the structure file 1519 points to has been clobbered or not. 1520 */ 1521 1522 int gzungetc(int c, gzFile file); 1523 /* 1524 Push one character back onto the stream to be read as the first character 1525 on the next read. At least one character of push-back is allowed. 1526 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1527 fail if c is -1, and may fail if a character has been pushed but not read 1528 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1529 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1530 The pushed character will be discarded if the stream is repositioned with 1531 gzseek() or gzrewind(). 1532 */ 1533 1534 int gzflush(gzFile file, int flush); 1535 /* 1536 Flushes all pending output into the compressed file. The parameter flush 1537 is as in the deflate() function. The return value is the zlib error number 1538 (see function gzerror below). gzflush is only permitted when writing. 1539 1540 If the flush parameter is Z_FINISH, the remaining data is written and the 1541 gzip stream is completed in the output. If gzwrite() is called again, a new 1542 gzip stream will be started in the output. gzread() is able to read such 1543 concatenated gzip streams. 1544 1545 gzflush should be called only when strictly necessary because it will 1546 degrade compression if called too often. 1547 */ 1548 1549 z_off_t gzseek(gzFile file, z_off_t offset, int whence); 1550 /* 1551 Sets the starting position for the next gzread or gzwrite on the given 1552 compressed file. The offset represents a number of bytes in the 1553 uncompressed data stream. The whence parameter is defined as in lseek(2); 1554 the value SEEK_END is not supported. 1555 1556 If the file is opened for reading, this function is emulated but can be 1557 extremely slow. If the file is opened for writing, only forward seeks are 1558 supported; gzseek then compresses a sequence of zeroes up to the new 1559 starting position. 1560 1561 gzseek returns the resulting offset location as measured in bytes from 1562 the beginning of the uncompressed stream, or -1 in case of error, in 1563 particular if the file is opened for writing and the new starting position 1564 would be before the current position. 1565 */ 1566 1567 int gzrewind(gzFile file); 1568 /* 1569 Rewinds the given file. This function is supported only for reading. 1570 1571 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1572 */ 1573 1574 z_off_t gztell(gzFile file); 1575 /* 1576 Returns the starting position for the next gzread or gzwrite on the given 1577 compressed file. This position represents a number of bytes in the 1578 uncompressed data stream, and is zero when starting, even if appending or 1579 reading a gzip stream from the middle of a file using gzdopen(). 1580 1581 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1582 */ 1583 1584 z_off_t gzoffset(gzFile file); 1585 /* 1586 Returns the current offset in the file being read or written. This offset 1587 includes the count of bytes that precede the gzip stream, for example when 1588 appending or when using gzdopen() for reading. When reading, the offset 1589 does not include as yet unused buffered input. This information can be used 1590 for a progress indicator. On error, gzoffset() returns -1. 1591 */ 1592 1593 int gzeof(gzFile file); 1594 /* 1595 Returns true (1) if the end-of-file indicator has been set while reading, 1596 false (0) otherwise. Note that the end-of-file indicator is set only if the 1597 read tried to go past the end of the input, but came up short. Therefore, 1598 just like feof(), gzeof() may return false even if there is no more data to 1599 read, in the event that the last read request was for the exact number of 1600 bytes remaining in the input file. This will happen if the input file size 1601 is an exact multiple of the buffer size. 1602 1603 If gzeof() returns true, then the read functions will return no more data, 1604 unless the end-of-file indicator is reset by gzclearerr() and the input file 1605 has grown since the previous end of file was detected. 1606 */ 1607 1608 int gzdirect(gzFile file); 1609 /* 1610 Returns true (1) if file is being copied directly while reading, or false 1611 (0) if file is a gzip stream being decompressed. 1612 1613 If the input file is empty, gzdirect() will return true, since the input 1614 does not contain a gzip stream. 1615 1616 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1617 cause buffers to be allocated to allow reading the file to determine if it 1618 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1619 gzdirect(). 1620 1621 When writing, gzdirect() returns true (1) if transparent writing was 1622 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1623 gzdirect() is not needed when writing. Transparent writing must be 1624 explicitly requested, so the application already knows the answer. When 1625 linking statically, using gzdirect() will include all of the zlib code for 1626 gzip file reading and decompression, which may not be desired.) 1627 */ 1628 1629 int gzclose(gzFile file); 1630 /* 1631 Flushes all pending output if necessary, closes the compressed file and 1632 deallocates the (de)compression state. Note that once file is closed, you 1633 cannot call gzerror with file, since its structures have been deallocated. 1634 gzclose must not be called more than once on the same file, just as free 1635 must not be called more than once on the same allocation. 1636 1637 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1638 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1639 last read ended in the middle of a gzip stream, or Z_OK on success. 1640 */ 1641 1642 int gzclose_r(gzFile file); 1643 int gzclose_w(gzFile file); 1644 /* 1645 Same as gzclose(), but gzclose_r() is only for use when reading, and 1646 gzclose_w() is only for use when writing or appending. The advantage to 1647 using these instead of gzclose() is that they avoid linking in zlib 1648 compression or decompression code that is not used when only reading or only 1649 writing respectively. If gzclose() is used, then both compression and 1650 decompression code will be included the application when linking to a static 1651 zlib library. 1652 */ 1653 1654 const(char)* gzerror(gzFile file, int* 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 void gzclearerr(gzFile file); 1671 /* 1672 Clears the error and end-of-file flags for file. This is analogous to the 1673 clearerr() function in stdio. This is useful for continuing to read a gzip 1674 file that is being written concurrently. 1675 */ 1676 1677 /* checksum functions */ 1678 1679 /* 1680 These functions are not related to compression but are exported 1681 anyway because they might be useful in applications using the compression 1682 library. 1683 */ 1684 1685 uint adler32(uint adler, const(ubyte)* buf, uint len); 1686 /* 1687 Update a running Adler-32 checksum with the bytes buf[0 .. len-1] and 1688 return the updated checksum. If buf is Z_NULL, this function returns the 1689 required initial value for the checksum. 1690 1691 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1692 much faster. 1693 1694 Usage example: 1695 1696 uLong adler = adler32(0L, Z_NULL, 0); 1697 1698 while (read_buffer(buffer, length) != EOF) 1699 adler = adler32(adler, buffer, length); 1700 1701 if (adler != original_adler) error(); 1702 */ 1703 1704 uint adler32_z (uint adler, const(ubyte)* buf, z_size_t len); 1705 /* 1706 Same as adler32(), but with a size_t length. 1707 */ 1708 1709 uint adler32_combine(uint adler1, uint adler2, z_off_t len2); 1710 /* 1711 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1712 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1713 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1714 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1715 that the z_off_t type (like off_t) is a signed integer. If len2 is 1716 negative, the result has no meaning or utility. 1717 */ 1718 1719 uint crc32(uint crc, const(ubyte)* buf, uint len); 1720 /* 1721 Update a running CRC-32 with the bytes buf[0 .. len-1] and return the 1722 updated CRC-32. If buf is Z_NULL, this function returns the required 1723 initial value for the crc. Pre- and post-conditioning (one's complement) is 1724 performed within this function so it shouldn't be done by the application. 1725 1726 Usage example: 1727 1728 uLong crc = crc32(0L, Z_NULL, 0); 1729 1730 while (read_buffer(buffer, length) != EOF) 1731 crc = crc32(crc, buffer, length); 1732 1733 if (crc != original_crc) error(); 1734 */ 1735 1736 uint crc32_z(uint adler, const(ubyte)* buf, z_size_t len); 1737 /* 1738 Same as crc32(), but with a size_t length. 1739 */ 1740 1741 uint crc32_combine(uint crc1, uint crc2, z_off_t len2); 1742 1743 /* 1744 Combine two CRC-32 check values into one. For two sequences of bytes, 1745 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1746 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1747 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1748 len2. 1749 */ 1750 1751 1752 /* various hacks, don't look :) */ 1753 1754 /* deflateInit and inflateInit are macros to allow checking the zlib version 1755 * and the compiler's view of z_stream: 1756 */ 1757 int deflateInit_(z_streamp strm, 1758 int level, 1759 const(char)* versionx, 1760 int stream_size); 1761 1762 int inflateInit_(z_streamp strm, 1763 const(char)* versionx, 1764 int stream_size); 1765 1766 int deflateInit2_(z_streamp strm, 1767 int level, 1768 int method, 1769 int windowBits, 1770 int memLevel, 1771 int strategy, 1772 const(char)* versionx, 1773 int stream_size); 1774 1775 int inflateBackInit_(z_stream* strm, 1776 int windowBits, 1777 ubyte* window, 1778 const(char)* z_version, 1779 int stream_size); 1780 1781 int inflateInit2_(z_streamp strm, 1782 int windowBits, 1783 const(char)* versionx, 1784 int stream_size); 1785 1786 const(char)* zError(int err); 1787 int inflateSyncPoint(z_streamp z); 1788 const(uint)* get_crc_table(); 1789