zlib.h 85 KB

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  1. /* zlib.h -- interface of the 'zlib' general purpose compression library
  2. version 1.2.7, May 2nd, 2012
  3. Copyright (C) 1995-2012 Jean-loup Gailly and Mark Adler
  4. This software is provided 'as-is', without any express or implied
  5. warranty. In no event will the authors be held liable for any damages
  6. arising from the use of this software.
  7. Permission is granted to anyone to use this software for any purpose,
  8. including commercial applications, and to alter it and redistribute it
  9. freely, subject to the following restrictions:
  10. 1. The origin of this software must not be misrepresented; you must not
  11. claim that you wrote the original software. If you use this software
  12. in a product, an acknowledgment in the product documentation would be
  13. appreciated but is not required.
  14. 2. Altered source versions must be plainly marked as such, and must not be
  15. misrepresented as being the original software.
  16. 3. This notice may not be removed or altered from any source distribution.
  17. Jean-loup Gailly Mark Adler
  18. jloup@gzip.org madler@alumni.caltech.edu
  19. The data format used by the zlib library is described by RFCs (Request for
  20. Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
  21. (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
  22. */
  23. #ifndef ZLIB_H
  24. #define ZLIB_H
  25. #include <zconf.h>
  26. #ifdef __cplusplus
  27. extern "C" {
  28. #endif
  29. #define ZLIB_VERSION "1.2.7"
  30. #define ZLIB_VERNUM 0x1270
  31. #define ZLIB_VER_MAJOR 1
  32. #define ZLIB_VER_MINOR 2
  33. #define ZLIB_VER_REVISION 7
  34. #define ZLIB_VER_SUBREVISION 0
  35. /*
  36. The 'zlib' compression library provides in-memory compression and
  37. decompression functions, including integrity checks of the uncompressed data.
  38. This version of the library supports only one compression method (deflation)
  39. but other algorithms will be added later and will have the same stream
  40. interface.
  41. Compression can be done in a single step if the buffers are large enough,
  42. or can be done by repeated calls of the compression function. In the latter
  43. case, the application must provide more input and/or consume the output
  44. (providing more output space) before each call.
  45. The compressed data format used by default by the in-memory functions is
  46. the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
  47. around a deflate stream, which is itself documented in RFC 1951.
  48. The library also supports reading and writing files in gzip (.gz) format
  49. with an interface similar to that of stdio using the functions that start
  50. with "gz". The gzip format is different from the zlib format. gzip is a
  51. gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
  52. This library can optionally read and write gzip streams in memory as well.
  53. The zlib format was designed to be compact and fast for use in memory
  54. and on communications channels. The gzip format was designed for single-
  55. file compression on file systems, has a larger header than zlib to maintain
  56. directory information, and uses a different, slower check method than zlib.
  57. The library does not install any signal handler. The decoder checks
  58. the consistency of the compressed data, so the library should never crash
  59. even in case of corrupted input.
  60. */
  61. typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
  62. typedef void (*free_func) OF((voidpf opaque, voidpf address));
  63. struct internal_state;
  64. typedef struct z_stream_s {
  65. z_const Bytef *next_in; /* next input byte */
  66. uInt avail_in; /* number of bytes available at next_in */
  67. uLong total_in; /* total number of input bytes read so far */
  68. Bytef *next_out; /* next output byte should be put there */
  69. uInt avail_out; /* remaining free space at next_out */
  70. uLong total_out; /* total number of bytes output so far */
  71. z_const char *msg; /* last error message, NULL if no error */
  72. struct internal_state FAR *state; /* not visible by applications */
  73. alloc_func zalloc; /* used to allocate the internal state */
  74. free_func zfree; /* used to free the internal state */
  75. voidpf opaque; /* private data object passed to zalloc and zfree */
  76. int data_type; /* best guess about the data type: binary or text */
  77. uLong adler; /* adler32 value of the uncompressed data */
  78. uLong reserved; /* reserved for future use */
  79. } z_stream;
  80. typedef z_stream FAR *z_streamp;
  81. /*
  82. gzip header information passed to and from zlib routines. See RFC 1952
  83. for more details on the meanings of these fields.
  84. */
  85. typedef struct gz_header_s {
  86. int text; /* true if compressed data believed to be text */
  87. uLong time; /* modification time */
  88. int xflags; /* extra flags (not used when writing a gzip file) */
  89. int os; /* operating system */
  90. Bytef *extra; /* pointer to extra field or Z_NULL if none */
  91. uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
  92. uInt extra_max; /* space at extra (only when reading header) */
  93. Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
  94. uInt name_max; /* space at name (only when reading header) */
  95. Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
  96. uInt comm_max; /* space at comment (only when reading header) */
  97. int hcrc; /* true if there was or will be a header crc */
  98. int done; /* true when done reading gzip header (not used
  99. when writing a gzip file) */
  100. } gz_header;
  101. typedef gz_header FAR *gz_headerp;
  102. /*
  103. The application must update next_in and avail_in when avail_in has dropped
  104. to zero. It must update next_out and avail_out when avail_out has dropped
  105. to zero. The application must initialize zalloc, zfree and opaque before
  106. calling the init function. All other fields are set by the compression
  107. library and must not be updated by the application.
  108. The opaque value provided by the application will be passed as the first
  109. parameter for calls of zalloc and zfree. This can be useful for custom
  110. memory management. The compression library attaches no meaning to the
  111. opaque value.
  112. zalloc must return Z_NULL if there is not enough memory for the object.
  113. If zlib is used in a multi-threaded application, zalloc and zfree must be
  114. thread safe.
  115. On 16-bit systems, the functions zalloc and zfree must be able to allocate
  116. exactly 65536 bytes, but will not be required to allocate more than this if
  117. the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
  118. returned by zalloc for objects of exactly 65536 bytes *must* have their
  119. offset normalized to zero. The default allocation function provided by this
  120. library ensures this (see zutil.c). To reduce memory requirements and avoid
  121. any allocation of 64K objects, at the expense of compression ratio, compile
  122. the library with -DMAX_WBITS=14 (see zconf.h).
  123. The fields total_in and total_out can be used for statistics or progress
  124. reports. After compression, total_in holds the total size of the
  125. uncompressed data and may be saved for use in the decompressor (particularly
  126. if the decompressor wants to decompress everything in a single step).
  127. */
  128. /* constants */
  129. #define Z_NO_FLUSH 0
  130. #define Z_PARTIAL_FLUSH 1
  131. #define Z_SYNC_FLUSH 2
  132. #define Z_FULL_FLUSH 3
  133. #define Z_FINISH 4
  134. #define Z_BLOCK 5
  135. #define Z_TREES 6
  136. /* Allowed flush values; see deflate() and inflate() below for details */
  137. #define Z_OK 0
  138. #define Z_STREAM_END 1
  139. #define Z_NEED_DICT 2
  140. #define Z_ERRNO (-1)
  141. #define Z_STREAM_ERROR (-2)
  142. #define Z_DATA_ERROR (-3)
  143. #define Z_MEM_ERROR (-4)
  144. #define Z_BUF_ERROR (-5)
  145. #define Z_VERSION_ERROR (-6)
  146. /* Return codes for the compression/decompression functions. Negative values
  147. * are errors, positive values are used for special but normal events.
  148. */
  149. #define Z_NO_COMPRESSION 0
  150. #define Z_BEST_SPEED 1
  151. #define Z_BEST_COMPRESSION 9
  152. #define Z_DEFAULT_COMPRESSION (-1)
  153. /* compression levels */
  154. #define Z_FILTERED 1
  155. #define Z_HUFFMAN_ONLY 2
  156. #define Z_RLE 3
  157. #define Z_FIXED 4
  158. #define Z_DEFAULT_STRATEGY 0
  159. /* compression strategy; see deflateInit2() below for details */
  160. #define Z_BINARY 0
  161. #define Z_TEXT 1
  162. #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
  163. #define Z_UNKNOWN 2
  164. /* Possible values of the data_type field (though see inflate()) */
  165. #define Z_DEFLATED 8
  166. /* The deflate compression method (the only one supported in this version) */
  167. #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
  168. #define zlib_version zlibVersion()
  169. /* for compatibility with versions < 1.0.2 */
  170. /* basic functions */
  171. ZEXTERN const char * ZEXPORT zlibVersion OF((void));
  172. /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
  173. If the first character differs, the library code actually used is not
  174. compatible with the zlib.h header file used by the application. This check
  175. is automatically made by deflateInit and inflateInit.
  176. */
  177. /*
  178. ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
  179. Initializes the internal stream state for compression. The fields
  180. zalloc, zfree and opaque must be initialized before by the caller. If
  181. zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
  182. allocation functions.
  183. The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
  184. 1 gives best speed, 9 gives best compression, 0 gives no compression at all
  185. (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
  186. requests a default compromise between speed and compression (currently
  187. equivalent to level 6).
  188. deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
  189. memory, Z_STREAM_ERROR if level is not a valid compression level, or
  190. Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
  191. with the version assumed by the caller (ZLIB_VERSION). msg is set to null
  192. if there is no error message. deflateInit does not perform any compression:
  193. this will be done by deflate().
  194. */
  195. ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
  196. /*
  197. deflate compresses as much data as possible, and stops when the input
  198. buffer becomes empty or the output buffer becomes full. It may introduce
  199. some output latency (reading input without producing any output) except when
  200. forced to flush.
  201. The detailed semantics are as follows. deflate performs one or both of the
  202. following actions:
  203. - Compress more input starting at next_in and update next_in and avail_in
  204. accordingly. If not all input can be processed (because there is not
  205. enough room in the output buffer), next_in and avail_in are updated and
  206. processing will resume at this point for the next call of deflate().
  207. - Provide more output starting at next_out and update next_out and avail_out
  208. accordingly. This action is forced if the parameter flush is non zero.
  209. Forcing flush frequently degrades the compression ratio, so this parameter
  210. should be set only when necessary (in interactive applications). Some
  211. output may be provided even if flush is not set.
  212. Before the call of deflate(), the application should ensure that at least
  213. one of the actions is possible, by providing more input and/or consuming more
  214. output, and updating avail_in or avail_out accordingly; avail_out should
  215. never be zero before the call. The application can consume the compressed
  216. output when it wants, for example when the output buffer is full (avail_out
  217. == 0), or after each call of deflate(). If deflate returns Z_OK and with
  218. zero avail_out, it must be called again after making room in the output
  219. buffer because there might be more output pending.
  220. Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
  221. decide how much data to accumulate before producing output, in order to
  222. maximize compression.
  223. If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
  224. flushed to the output buffer and the output is aligned on a byte boundary, so
  225. that the decompressor can get all input data available so far. (In
  226. particular avail_in is zero after the call if enough output space has been
  227. provided before the call.) Flushing may degrade compression for some
  228. compression algorithms and so it should be used only when necessary. This
  229. completes the current deflate block and follows it with an empty stored block
  230. that is three bits plus filler bits to the next byte, followed by four bytes
  231. (00 00 ff ff).
  232. If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
  233. output buffer, but the output is not aligned to a byte boundary. All of the
  234. input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
  235. This completes the current deflate block and follows it with an empty fixed
  236. codes block that is 10 bits long. This assures that enough bytes are output
  237. in order for the decompressor to finish the block before the empty fixed code
  238. block.
  239. If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
  240. for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
  241. seven bits of the current block are held to be written as the next byte after
  242. the next deflate block is completed. In this case, the decompressor may not
  243. be provided enough bits at this point in order to complete decompression of
  244. the data provided so far to the compressor. It may need to wait for the next
  245. block to be emitted. This is for advanced applications that need to control
  246. the emission of deflate blocks.
  247. If flush is set to Z_FULL_FLUSH, all output is flushed as with
  248. Z_SYNC_FLUSH, and the compression state is reset so that decompression can
  249. restart from this point if previous compressed data has been damaged or if
  250. random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
  251. compression.
  252. If deflate returns with avail_out == 0, this function must be called again
  253. with the same value of the flush parameter and more output space (updated
  254. avail_out), until the flush is complete (deflate returns with non-zero
  255. avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
  256. avail_out is greater than six to avoid repeated flush markers due to
  257. avail_out == 0 on return.
  258. If the parameter flush is set to Z_FINISH, pending input is processed,
  259. pending output is flushed and deflate returns with Z_STREAM_END if there was
  260. enough output space; if deflate returns with Z_OK, this function must be
  261. called again with Z_FINISH and more output space (updated avail_out) but no
  262. more input data, until it returns with Z_STREAM_END or an error. After
  263. deflate has returned Z_STREAM_END, the only possible operations on the stream
  264. are deflateReset or deflateEnd.
  265. Z_FINISH can be used immediately after deflateInit if all the compression
  266. is to be done in a single step. In this case, avail_out must be at least the
  267. value returned by deflateBound (see below). Then deflate is guaranteed to
  268. return Z_STREAM_END. If not enough output space is provided, deflate will
  269. not return Z_STREAM_END, and it must be called again as described above.
  270. deflate() sets strm->adler to the adler32 checksum of all input read
  271. so far (that is, total_in bytes).
  272. deflate() may update strm->data_type if it can make a good guess about
  273. the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
  274. binary. This field is only for information purposes and does not affect the
  275. compression algorithm in any manner.
  276. deflate() returns Z_OK if some progress has been made (more input
  277. processed or more output produced), Z_STREAM_END if all input has been
  278. consumed and all output has been produced (only when flush is set to
  279. Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
  280. if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
  281. (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
  282. fatal, and deflate() can be called again with more input and more output
  283. space to continue compressing.
  284. */
  285. ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
  286. /*
  287. All dynamically allocated data structures for this stream are freed.
  288. This function discards any unprocessed input and does not flush any pending
  289. output.
  290. deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
  291. stream state was inconsistent, Z_DATA_ERROR if the stream was freed
  292. prematurely (some input or output was discarded). In the error case, msg
  293. may be set but then points to a static string (which must not be
  294. deallocated).
  295. */
  296. /*
  297. ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
  298. Initializes the internal stream state for decompression. The fields
  299. next_in, avail_in, zalloc, zfree and opaque must be initialized before by
  300. the caller. If next_in is not Z_NULL and avail_in is large enough (the
  301. exact value depends on the compression method), inflateInit determines the
  302. compression method from the zlib header and allocates all data structures
  303. accordingly; otherwise the allocation will be deferred to the first call of
  304. inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
  305. use default allocation functions.
  306. inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
  307. memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
  308. version assumed by the caller, or Z_STREAM_ERROR if the parameters are
  309. invalid, such as a null pointer to the structure. msg is set to null if
  310. there is no error message. inflateInit does not perform any decompression
  311. apart from possibly reading the zlib header if present: actual decompression
  312. will be done by inflate(). (So next_in and avail_in may be modified, but
  313. next_out and avail_out are unused and unchanged.) The current implementation
  314. of inflateInit() does not process any header information -- that is deferred
  315. until inflate() is called.
  316. */
  317. ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
  318. /*
  319. inflate decompresses as much data as possible, and stops when the input
  320. buffer becomes empty or the output buffer becomes full. It may introduce
  321. some output latency (reading input without producing any output) except when
  322. forced to flush.
  323. The detailed semantics are as follows. inflate performs one or both of the
  324. following actions:
  325. - Decompress more input starting at next_in and update next_in and avail_in
  326. accordingly. If not all input can be processed (because there is not
  327. enough room in the output buffer), next_in is updated and processing will
  328. resume at this point for the next call of inflate().
  329. - Provide more output starting at next_out and update next_out and avail_out
  330. accordingly. inflate() provides as much output as possible, until there is
  331. no more input data or no more space in the output buffer (see below about
  332. the flush parameter).
  333. Before the call of inflate(), the application should ensure that at least
  334. one of the actions is possible, by providing more input and/or consuming more
  335. output, and updating the next_* and avail_* values accordingly. The
  336. application can consume the uncompressed output when it wants, for example
  337. when the output buffer is full (avail_out == 0), or after each call of
  338. inflate(). If inflate returns Z_OK and with zero avail_out, it must be
  339. called again after making room in the output buffer because there might be
  340. more output pending.
  341. The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
  342. Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
  343. output as possible to the output buffer. Z_BLOCK requests that inflate()
  344. stop if and when it gets to the next deflate block boundary. When decoding
  345. the zlib or gzip format, this will cause inflate() to return immediately
  346. after the header and before the first block. When doing a raw inflate,
  347. inflate() will go ahead and process the first block, and will return when it
  348. gets to the end of that block, or when it runs out of data.
  349. The Z_BLOCK option assists in appending to or combining deflate streams.
  350. Also to assist in this, on return inflate() will set strm->data_type to the
  351. number of unused bits in the last byte taken from strm->next_in, plus 64 if
  352. inflate() is currently decoding the last block in the deflate stream, plus
  353. 128 if inflate() returned immediately after decoding an end-of-block code or
  354. decoding the complete header up to just before the first byte of the deflate
  355. stream. The end-of-block will not be indicated until all of the uncompressed
  356. data from that block has been written to strm->next_out. The number of
  357. unused bits may in general be greater than seven, except when bit 7 of
  358. data_type is set, in which case the number of unused bits will be less than
  359. eight. data_type is set as noted here every time inflate() returns for all
  360. flush options, and so can be used to determine the amount of currently
  361. consumed input in bits.
  362. The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
  363. end of each deflate block header is reached, before any actual data in that
  364. block is decoded. This allows the caller to determine the length of the
  365. deflate block header for later use in random access within a deflate block.
  366. 256 is added to the value of strm->data_type when inflate() returns
  367. immediately after reaching the end of the deflate block header.
  368. inflate() should normally be called until it returns Z_STREAM_END or an
  369. error. However if all decompression is to be performed in a single step (a
  370. single call of inflate), the parameter flush should be set to Z_FINISH. In
  371. this case all pending input is processed and all pending output is flushed;
  372. avail_out must be large enough to hold all of the uncompressed data for the
  373. operation to complete. (The size of the uncompressed data may have been
  374. saved by the compressor for this purpose.) The use of Z_FINISH is not
  375. required to perform an inflation in one step. However it may be used to
  376. inform inflate that a faster approach can be used for the single inflate()
  377. call. Z_FINISH also informs inflate to not maintain a sliding window if the
  378. stream completes, which reduces inflate's memory footprint. If the stream
  379. does not complete, either because not all of the stream is provided or not
  380. enough output space is provided, then a sliding window will be allocated and
  381. inflate() can be called again to continue the operation as if Z_NO_FLUSH had
  382. been used.
  383. In this implementation, inflate() always flushes as much output as
  384. possible to the output buffer, and always uses the faster approach on the
  385. first call. So the effects of the flush parameter in this implementation are
  386. on the return value of inflate() as noted below, when inflate() returns early
  387. when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
  388. memory for a sliding window when Z_FINISH is used.
  389. If a preset dictionary is needed after this call (see inflateSetDictionary
  390. below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
  391. chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
  392. strm->adler to the Adler-32 checksum of all output produced so far (that is,
  393. total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
  394. below. At the end of the stream, inflate() checks that its computed adler32
  395. checksum is equal to that saved by the compressor and returns Z_STREAM_END
  396. only if the checksum is correct.
  397. inflate() can decompress and check either zlib-wrapped or gzip-wrapped
  398. deflate data. The header type is detected automatically, if requested when
  399. initializing with inflateInit2(). Any information contained in the gzip
  400. header is not retained, so applications that need that information should
  401. instead use raw inflate, see inflateInit2() below, or inflateBack() and
  402. perform their own processing of the gzip header and trailer. When processing
  403. gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
  404. producted so far. The CRC-32 is checked against the gzip trailer.
  405. inflate() returns Z_OK if some progress has been made (more input processed
  406. or more output produced), Z_STREAM_END if the end of the compressed data has
  407. been reached and all uncompressed output has been produced, Z_NEED_DICT if a
  408. preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
  409. corrupted (input stream not conforming to the zlib format or incorrect check
  410. value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
  411. next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
  412. Z_BUF_ERROR if no progress is possible or if there was not enough room in the
  413. output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
  414. inflate() can be called again with more input and more output space to
  415. continue decompressing. If Z_DATA_ERROR is returned, the application may
  416. then call inflateSync() to look for a good compression block if a partial
  417. recovery of the data is desired.
  418. */
  419. ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
  420. /*
  421. All dynamically allocated data structures for this stream are freed.
  422. This function discards any unprocessed input and does not flush any pending
  423. output.
  424. inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
  425. was inconsistent. In the error case, msg may be set but then points to a
  426. static string (which must not be deallocated).
  427. */
  428. /* Advanced functions */
  429. /*
  430. The following functions are needed only in some special applications.
  431. */
  432. /*
  433. ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
  434. int level,
  435. int method,
  436. int windowBits,
  437. int memLevel,
  438. int strategy));
  439. This is another version of deflateInit with more compression options. The
  440. fields next_in, zalloc, zfree and opaque must be initialized before by the
  441. caller.
  442. The method parameter is the compression method. It must be Z_DEFLATED in
  443. this version of the library.
  444. The windowBits parameter is the base two logarithm of the window size
  445. (the size of the history buffer). It should be in the range 8..15 for this
  446. version of the library. Larger values of this parameter result in better
  447. compression at the expense of memory usage. The default value is 15 if
  448. deflateInit is used instead.
  449. windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
  450. determines the window size. deflate() will then generate raw deflate data
  451. with no zlib header or trailer, and will not compute an adler32 check value.
  452. windowBits can also be greater than 15 for optional gzip encoding. Add
  453. 16 to windowBits to write a simple gzip header and trailer around the
  454. compressed data instead of a zlib wrapper. The gzip header will have no
  455. file name, no extra data, no comment, no modification time (set to zero), no
  456. header crc, and the operating system will be set to 255 (unknown). If a
  457. gzip stream is being written, strm->adler is a crc32 instead of an adler32.
  458. The memLevel parameter specifies how much memory should be allocated
  459. for the internal compression state. memLevel=1 uses minimum memory but is
  460. slow and reduces compression ratio; memLevel=9 uses maximum memory for
  461. optimal speed. The default value is 8. See zconf.h for total memory usage
  462. as a function of windowBits and memLevel.
  463. The strategy parameter is used to tune the compression algorithm. Use the
  464. value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
  465. filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
  466. string match), or Z_RLE to limit match distances to one (run-length
  467. encoding). Filtered data consists mostly of small values with a somewhat
  468. random distribution. In this case, the compression algorithm is tuned to
  469. compress them better. The effect of Z_FILTERED is to force more Huffman
  470. coding and less string matching; it is somewhat intermediate between
  471. Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
  472. fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
  473. strategy parameter only affects the compression ratio but not the
  474. correctness of the compressed output even if it is not set appropriately.
  475. Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
  476. decoder for special applications.
  477. deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  478. memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
  479. method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
  480. incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
  481. set to null if there is no error message. deflateInit2 does not perform any
  482. compression: this will be done by deflate().
  483. */
  484. ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
  485. const Bytef *dictionary,
  486. uInt dictLength));
  487. /*
  488. Initializes the compression dictionary from the given byte sequence
  489. without producing any compressed output. When using the zlib format, this
  490. function must be called immediately after deflateInit, deflateInit2 or
  491. deflateReset, and before any call of deflate. When doing raw deflate, this
  492. function must be called either before any call of deflate, or immediately
  493. after the completion of a deflate block, i.e. after all input has been
  494. consumed and all output has been delivered when using any of the flush
  495. options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
  496. compressor and decompressor must use exactly the same dictionary (see
  497. inflateSetDictionary).
  498. The dictionary should consist of strings (byte sequences) that are likely
  499. to be encountered later in the data to be compressed, with the most commonly
  500. used strings preferably put towards the end of the dictionary. Using a
  501. dictionary is most useful when the data to be compressed is short and can be
  502. predicted with good accuracy; the data can then be compressed better than
  503. with the default empty dictionary.
  504. Depending on the size of the compression data structures selected by
  505. deflateInit or deflateInit2, a part of the dictionary may in effect be
  506. discarded, for example if the dictionary is larger than the window size
  507. provided in deflateInit or deflateInit2. Thus the strings most likely to be
  508. useful should be put at the end of the dictionary, not at the front. In
  509. addition, the current implementation of deflate will use at most the window
  510. size minus 262 bytes of the provided dictionary.
  511. Upon return of this function, strm->adler is set to the adler32 value
  512. of the dictionary; the decompressor may later use this value to determine
  513. which dictionary has been used by the compressor. (The adler32 value
  514. applies to the whole dictionary even if only a subset of the dictionary is
  515. actually used by the compressor.) If a raw deflate was requested, then the
  516. adler32 value is not computed and strm->adler is not set.
  517. deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
  518. parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
  519. inconsistent (for example if deflate has already been called for this stream
  520. or if not at a block boundary for raw deflate). deflateSetDictionary does
  521. not perform any compression: this will be done by deflate().
  522. */
  523. ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
  524. z_streamp source));
  525. /*
  526. Sets the destination stream as a complete copy of the source stream.
  527. This function can be useful when several compression strategies will be
  528. tried, for example when there are several ways of pre-processing the input
  529. data with a filter. The streams that will be discarded should then be freed
  530. by calling deflateEnd. Note that deflateCopy duplicates the internal
  531. compression state which can be quite large, so this strategy is slow and can
  532. consume lots of memory.
  533. deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
  534. enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
  535. (such as zalloc being Z_NULL). msg is left unchanged in both source and
  536. destination.
  537. */
  538. ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
  539. /*
  540. This function is equivalent to deflateEnd followed by deflateInit,
  541. but does not free and reallocate all the internal compression state. The
  542. stream will keep the same compression level and any other attributes that
  543. may have been set by deflateInit2.
  544. deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  545. stream state was inconsistent (such as zalloc or state being Z_NULL).
  546. */
  547. ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
  548. int level,
  549. int strategy));
  550. /*
  551. Dynamically update the compression level and compression strategy. The
  552. interpretation of level and strategy is as in deflateInit2. This can be
  553. used to switch between compression and straight copy of the input data, or
  554. to switch to a different kind of input data requiring a different strategy.
  555. If the compression level is changed, the input available so far is
  556. compressed with the old level (and may be flushed); the new level will take
  557. effect only at the next call of deflate().
  558. Before the call of deflateParams, the stream state must be set as for
  559. a call of deflate(), since the currently available input may have to be
  560. compressed and flushed. In particular, strm->avail_out must be non-zero.
  561. deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
  562. stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
  563. strm->avail_out was zero.
  564. */
  565. ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
  566. int good_length,
  567. int max_lazy,
  568. int nice_length,
  569. int max_chain));
  570. /*
  571. Fine tune deflate's internal compression parameters. This should only be
  572. used by someone who understands the algorithm used by zlib's deflate for
  573. searching for the best matching string, and even then only by the most
  574. fanatic optimizer trying to squeeze out the last compressed bit for their
  575. specific input data. Read the deflate.c source code for the meaning of the
  576. max_lazy, good_length, nice_length, and max_chain parameters.
  577. deflateTune() can be called after deflateInit() or deflateInit2(), and
  578. returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
  579. */
  580. ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
  581. uLong sourceLen));
  582. /*
  583. deflateBound() returns an upper bound on the compressed size after
  584. deflation of sourceLen bytes. It must be called after deflateInit() or
  585. deflateInit2(), and after deflateSetHeader(), if used. This would be used
  586. to allocate an output buffer for deflation in a single pass, and so would be
  587. called before deflate(). If that first deflate() call is provided the
  588. sourceLen input bytes, an output buffer allocated to the size returned by
  589. deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
  590. to return Z_STREAM_END. Note that it is possible for the compressed size to
  591. be larger than the value returned by deflateBound() if flush options other
  592. than Z_FINISH or Z_NO_FLUSH are used.
  593. */
  594. ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
  595. unsigned *pending,
  596. int *bits));
  597. /*
  598. deflatePending() returns the number of bytes and bits of output that have
  599. been generated, but not yet provided in the available output. The bytes not
  600. provided would be due to the available output space having being consumed.
  601. The number of bits of output not provided are between 0 and 7, where they
  602. await more bits to join them in order to fill out a full byte. If pending
  603. or bits are Z_NULL, then those values are not set.
  604. deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
  605. stream state was inconsistent.
  606. */
  607. ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
  608. int bits,
  609. int value));
  610. /*
  611. deflatePrime() inserts bits in the deflate output stream. The intent
  612. is that this function is used to start off the deflate output with the bits
  613. leftover from a previous deflate stream when appending to it. As such, this
  614. function can only be used for raw deflate, and must be used before the first
  615. deflate() call after a deflateInit2() or deflateReset(). bits must be less
  616. than or equal to 16, and that many of the least significant bits of value
  617. will be inserted in the output.
  618. deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
  619. room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
  620. source stream state was inconsistent.
  621. */
  622. ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
  623. gz_headerp head));
  624. /*
  625. deflateSetHeader() provides gzip header information for when a gzip
  626. stream is requested by deflateInit2(). deflateSetHeader() may be called
  627. after deflateInit2() or deflateReset() and before the first call of
  628. deflate(). The text, time, os, extra field, name, and comment information
  629. in the provided gz_header structure are written to the gzip header (xflag is
  630. ignored -- the extra flags are set according to the compression level). The
  631. caller must assure that, if not Z_NULL, name and comment are terminated with
  632. a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
  633. available there. If hcrc is true, a gzip header crc is included. Note that
  634. the current versions of the command-line version of gzip (up through version
  635. 1.3.x) do not support header crc's, and will report that it is a "multi-part
  636. gzip file" and give up.
  637. If deflateSetHeader is not used, the default gzip header has text false,
  638. the time set to zero, and os set to 255, with no extra, name, or comment
  639. fields. The gzip header is returned to the default state by deflateReset().
  640. deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
  641. stream state was inconsistent.
  642. */
  643. /*
  644. ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
  645. int windowBits));
  646. This is another version of inflateInit with an extra parameter. The
  647. fields next_in, avail_in, zalloc, zfree and opaque must be initialized
  648. before by the caller.
  649. The windowBits parameter is the base two logarithm of the maximum window
  650. size (the size of the history buffer). It should be in the range 8..15 for
  651. this version of the library. The default value is 15 if inflateInit is used
  652. instead. windowBits must be greater than or equal to the windowBits value
  653. provided to deflateInit2() while compressing, or it must be equal to 15 if
  654. deflateInit2() was not used. If a compressed stream with a larger window
  655. size is given as input, inflate() will return with the error code
  656. Z_DATA_ERROR instead of trying to allocate a larger window.
  657. windowBits can also be zero to request that inflate use the window size in
  658. the zlib header of the compressed stream.
  659. windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
  660. determines the window size. inflate() will then process raw deflate data,
  661. not looking for a zlib or gzip header, not generating a check value, and not
  662. looking for any check values for comparison at the end of the stream. This
  663. is for use with other formats that use the deflate compressed data format
  664. such as zip. Those formats provide their own check values. If a custom
  665. format is developed using the raw deflate format for compressed data, it is
  666. recommended that a check value such as an adler32 or a crc32 be applied to
  667. the uncompressed data as is done in the zlib, gzip, and zip formats. For
  668. most applications, the zlib format should be used as is. Note that comments
  669. above on the use in deflateInit2() applies to the magnitude of windowBits.
  670. windowBits can also be greater than 15 for optional gzip decoding. Add
  671. 32 to windowBits to enable zlib and gzip decoding with automatic header
  672. detection, or add 16 to decode only the gzip format (the zlib format will
  673. return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
  674. crc32 instead of an adler32.
  675. inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  676. memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
  677. version assumed by the caller, or Z_STREAM_ERROR if the parameters are
  678. invalid, such as a null pointer to the structure. msg is set to null if
  679. there is no error message. inflateInit2 does not perform any decompression
  680. apart from possibly reading the zlib header if present: actual decompression
  681. will be done by inflate(). (So next_in and avail_in may be modified, but
  682. next_out and avail_out are unused and unchanged.) The current implementation
  683. of inflateInit2() does not process any header information -- that is
  684. deferred until inflate() is called.
  685. */
  686. ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
  687. const Bytef *dictionary,
  688. uInt dictLength));
  689. /*
  690. Initializes the decompression dictionary from the given uncompressed byte
  691. sequence. This function must be called immediately after a call of inflate,
  692. if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
  693. can be determined from the adler32 value returned by that call of inflate.
  694. The compressor and decompressor must use exactly the same dictionary (see
  695. deflateSetDictionary). For raw inflate, this function can be called at any
  696. time to set the dictionary. If the provided dictionary is smaller than the
  697. window and there is already data in the window, then the provided dictionary
  698. will amend what's there. The application must insure that the dictionary
  699. that was used for compression is provided.
  700. inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
  701. parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
  702. inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
  703. expected one (incorrect adler32 value). inflateSetDictionary does not
  704. perform any decompression: this will be done by subsequent calls of
  705. inflate().
  706. */
  707. ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
  708. /*
  709. Skips invalid compressed data until a possible full flush point (see above
  710. for the description of deflate with Z_FULL_FLUSH) can be found, or until all
  711. available input is skipped. No output is provided.
  712. inflateSync searches for a 00 00 FF FF pattern in the compressed data.
  713. All full flush points have this pattern, but not all occurences of this
  714. pattern are full flush points.
  715. inflateSync returns Z_OK if a possible full flush point has been found,
  716. Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
  717. has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
  718. In the success case, the application may save the current current value of
  719. total_in which indicates where valid compressed data was found. In the
  720. error case, the application may repeatedly call inflateSync, providing more
  721. input each time, until success or end of the input data.
  722. */
  723. ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
  724. z_streamp source));
  725. /*
  726. Sets the destination stream as a complete copy of the source stream.
  727. This function can be useful when randomly accessing a large stream. The
  728. first pass through the stream can periodically record the inflate state,
  729. allowing restarting inflate at those points when randomly accessing the
  730. stream.
  731. inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
  732. enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
  733. (such as zalloc being Z_NULL). msg is left unchanged in both source and
  734. destination.
  735. */
  736. ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
  737. /*
  738. This function is equivalent to inflateEnd followed by inflateInit,
  739. but does not free and reallocate all the internal decompression state. The
  740. stream will keep attributes that may have been set by inflateInit2.
  741. inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  742. stream state was inconsistent (such as zalloc or state being Z_NULL).
  743. */
  744. ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
  745. int windowBits));
  746. /*
  747. This function is the same as inflateReset, but it also permits changing
  748. the wrap and window size requests. The windowBits parameter is interpreted
  749. the same as it is for inflateInit2.
  750. inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
  751. stream state was inconsistent (such as zalloc or state being Z_NULL), or if
  752. the windowBits parameter is invalid.
  753. */
  754. ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
  755. int bits,
  756. int value));
  757. /*
  758. This function inserts bits in the inflate input stream. The intent is
  759. that this function is used to start inflating at a bit position in the
  760. middle of a byte. The provided bits will be used before any bytes are used
  761. from next_in. This function should only be used with raw inflate, and
  762. should be used before the first inflate() call after inflateInit2() or
  763. inflateReset(). bits must be less than or equal to 16, and that many of the
  764. least significant bits of value will be inserted in the input.
  765. If bits is negative, then the input stream bit buffer is emptied. Then
  766. inflatePrime() can be called again to put bits in the buffer. This is used
  767. to clear out bits leftover after feeding inflate a block description prior
  768. to feeding inflate codes.
  769. inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
  770. stream state was inconsistent.
  771. */
  772. ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
  773. /*
  774. This function returns two values, one in the lower 16 bits of the return
  775. value, and the other in the remaining upper bits, obtained by shifting the
  776. return value down 16 bits. If the upper value is -1 and the lower value is
  777. zero, then inflate() is currently decoding information outside of a block.
  778. If the upper value is -1 and the lower value is non-zero, then inflate is in
  779. the middle of a stored block, with the lower value equaling the number of
  780. bytes from the input remaining to copy. If the upper value is not -1, then
  781. it is the number of bits back from the current bit position in the input of
  782. the code (literal or length/distance pair) currently being processed. In
  783. that case the lower value is the number of bytes already emitted for that
  784. code.
  785. A code is being processed if inflate is waiting for more input to complete
  786. decoding of the code, or if it has completed decoding but is waiting for
  787. more output space to write the literal or match data.
  788. inflateMark() is used to mark locations in the input data for random
  789. access, which may be at bit positions, and to note those cases where the
  790. output of a code may span boundaries of random access blocks. The current
  791. location in the input stream can be determined from avail_in and data_type
  792. as noted in the description for the Z_BLOCK flush parameter for inflate.
  793. inflateMark returns the value noted above or -1 << 16 if the provided
  794. source stream state was inconsistent.
  795. */
  796. ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
  797. gz_headerp head));
  798. /*
  799. inflateGetHeader() requests that gzip header information be stored in the
  800. provided gz_header structure. inflateGetHeader() may be called after
  801. inflateInit2() or inflateReset(), and before the first call of inflate().
  802. As inflate() processes the gzip stream, head->done is zero until the header
  803. is completed, at which time head->done is set to one. If a zlib stream is
  804. being decoded, then head->done is set to -1 to indicate that there will be
  805. no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
  806. used to force inflate() to return immediately after header processing is
  807. complete and before any actual data is decompressed.
  808. The text, time, xflags, and os fields are filled in with the gzip header
  809. contents. hcrc is set to true if there is a header CRC. (The header CRC
  810. was valid if done is set to one.) If extra is not Z_NULL, then extra_max
  811. contains the maximum number of bytes to write to extra. Once done is true,
  812. extra_len contains the actual extra field length, and extra contains the
  813. extra field, or that field truncated if extra_max is less than extra_len.
  814. If name is not Z_NULL, then up to name_max characters are written there,
  815. terminated with a zero unless the length is greater than name_max. If
  816. comment is not Z_NULL, then up to comm_max characters are written there,
  817. terminated with a zero unless the length is greater than comm_max. When any
  818. of extra, name, or comment are not Z_NULL and the respective field is not
  819. present in the header, then that field is set to Z_NULL to signal its
  820. absence. This allows the use of deflateSetHeader() with the returned
  821. structure to duplicate the header. However if those fields are set to
  822. allocated memory, then the application will need to save those pointers
  823. elsewhere so that they can be eventually freed.
  824. If inflateGetHeader is not used, then the header information is simply
  825. discarded. The header is always checked for validity, including the header
  826. CRC if present. inflateReset() will reset the process to discard the header
  827. information. The application would need to call inflateGetHeader() again to
  828. retrieve the header from the next gzip stream.
  829. inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
  830. stream state was inconsistent.
  831. */
  832. /*
  833. ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
  834. unsigned char FAR *window));
  835. Initialize the internal stream state for decompression using inflateBack()
  836. calls. The fields zalloc, zfree and opaque in strm must be initialized
  837. before the call. If zalloc and zfree are Z_NULL, then the default library-
  838. derived memory allocation routines are used. windowBits is the base two
  839. logarithm of the window size, in the range 8..15. window is a caller
  840. supplied buffer of that size. Except for special applications where it is
  841. assured that deflate was used with small window sizes, windowBits must be 15
  842. and a 32K byte window must be supplied to be able to decompress general
  843. deflate streams.
  844. See inflateBack() for the usage of these routines.
  845. inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
  846. the parameters are invalid, Z_MEM_ERROR if the internal state could not be
  847. allocated, or Z_VERSION_ERROR if the version of the library does not match
  848. the version of the header file.
  849. */
  850. typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
  851. typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
  852. ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
  853. in_func in, void FAR *in_desc,
  854. out_func out, void FAR *out_desc));
  855. /*
  856. inflateBack() does a raw inflate with a single call using a call-back
  857. interface for input and output. This is more efficient than inflate() for
  858. file i/o applications in that it avoids copying between the output and the
  859. sliding window by simply making the window itself the output buffer. This
  860. function trusts the application to not change the output buffer passed by
  861. the output function, at least until inflateBack() returns.
  862. inflateBackInit() must be called first to allocate the internal state
  863. and to initialize the state with the user-provided window buffer.
  864. inflateBack() may then be used multiple times to inflate a complete, raw
  865. deflate stream with each call. inflateBackEnd() is then called to free the
  866. allocated state.
  867. A raw deflate stream is one with no zlib or gzip header or trailer.
  868. This routine would normally be used in a utility that reads zip or gzip
  869. files and writes out uncompressed files. The utility would decode the
  870. header and process the trailer on its own, hence this routine expects only
  871. the raw deflate stream to decompress. This is different from the normal
  872. behavior of inflate(), which expects either a zlib or gzip header and
  873. trailer around the deflate stream.
  874. inflateBack() uses two subroutines supplied by the caller that are then
  875. called by inflateBack() for input and output. inflateBack() calls those
  876. routines until it reads a complete deflate stream and writes out all of the
  877. uncompressed data, or until it encounters an error. The function's
  878. parameters and return types are defined above in the in_func and out_func
  879. typedefs. inflateBack() will call in(in_desc, &buf) which should return the
  880. number of bytes of provided input, and a pointer to that input in buf. If
  881. there is no input available, in() must return zero--buf is ignored in that
  882. case--and inflateBack() will return a buffer error. inflateBack() will call
  883. out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
  884. should return zero on success, or non-zero on failure. If out() returns
  885. non-zero, inflateBack() will return with an error. Neither in() nor out()
  886. are permitted to change the contents of the window provided to
  887. inflateBackInit(), which is also the buffer that out() uses to write from.
  888. The length written by out() will be at most the window size. Any non-zero
  889. amount of input may be provided by in().
  890. For convenience, inflateBack() can be provided input on the first call by
  891. setting strm->next_in and strm->avail_in. If that input is exhausted, then
  892. in() will be called. Therefore strm->next_in must be initialized before
  893. calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
  894. immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
  895. must also be initialized, and then if strm->avail_in is not zero, input will
  896. initially be taken from strm->next_in[0 .. strm->avail_in - 1].
  897. The in_desc and out_desc parameters of inflateBack() is passed as the
  898. first parameter of in() and out() respectively when they are called. These
  899. descriptors can be optionally used to pass any information that the caller-
  900. supplied in() and out() functions need to do their job.
  901. On return, inflateBack() will set strm->next_in and strm->avail_in to
  902. pass back any unused input that was provided by the last in() call. The
  903. return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
  904. if in() or out() returned an error, Z_DATA_ERROR if there was a format error
  905. in the deflate stream (in which case strm->msg is set to indicate the nature
  906. of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
  907. In the case of Z_BUF_ERROR, an input or output error can be distinguished
  908. using strm->next_in which will be Z_NULL only if in() returned an error. If
  909. strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
  910. non-zero. (in() will always be called before out(), so strm->next_in is
  911. assured to be defined if out() returns non-zero.) Note that inflateBack()
  912. cannot return Z_OK.
  913. */
  914. ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
  915. /*
  916. All memory allocated by inflateBackInit() is freed.
  917. inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
  918. state was inconsistent.
  919. */
  920. ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
  921. /* Return flags indicating compile-time options.
  922. Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
  923. 1.0: size of uInt
  924. 3.2: size of uLong
  925. 5.4: size of voidpf (pointer)
  926. 7.6: size of z_off_t
  927. Compiler, assembler, and debug options:
  928. 8: DEBUG
  929. 9: ASMV or ASMINF -- use ASM code
  930. 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
  931. 11: 0 (reserved)
  932. One-time table building (smaller code, but not thread-safe if true):
  933. 12: BUILDFIXED -- build static block decoding tables when needed
  934. 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
  935. 14,15: 0 (reserved)
  936. Library content (indicates missing functionality):
  937. 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
  938. deflate code when not needed)
  939. 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
  940. and decode gzip streams (to avoid linking crc code)
  941. 18-19: 0 (reserved)
  942. Operation variations (changes in library functionality):
  943. 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
  944. 21: FASTEST -- deflate algorithm with only one, lowest compression level
  945. 22,23: 0 (reserved)
  946. The sprintf variant used by gzprintf (zero is best):
  947. 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
  948. 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
  949. 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
  950. Remainder:
  951. 27-31: 0 (reserved)
  952. */
  953. #ifndef Z_SOLO
  954. /* utility functions */
  955. /*
  956. The following utility functions are implemented on top of the basic
  957. stream-oriented functions. To simplify the interface, some default options
  958. are assumed (compression level and memory usage, standard memory allocation
  959. functions). The source code of these utility functions can be modified if
  960. you need special options.
  961. */
  962. ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
  963. const Bytef *source, uLong sourceLen));
  964. /*
  965. Compresses the source buffer into the destination buffer. sourceLen is
  966. the byte length of the source buffer. Upon entry, destLen is the total size
  967. of the destination buffer, which must be at least the value returned by
  968. compressBound(sourceLen). Upon exit, destLen is the actual size of the
  969. compressed buffer.
  970. compress returns Z_OK if success, Z_MEM_ERROR if there was not
  971. enough memory, Z_BUF_ERROR if there was not enough room in the output
  972. buffer.
  973. */
  974. ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
  975. const Bytef *source, uLong sourceLen,
  976. int level));
  977. /*
  978. Compresses the source buffer into the destination buffer. The level
  979. parameter has the same meaning as in deflateInit. sourceLen is the byte
  980. length of the source buffer. Upon entry, destLen is the total size of the
  981. destination buffer, which must be at least the value returned by
  982. compressBound(sourceLen). Upon exit, destLen is the actual size of the
  983. compressed buffer.
  984. compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  985. memory, Z_BUF_ERROR if there was not enough room in the output buffer,
  986. Z_STREAM_ERROR if the level parameter is invalid.
  987. */
  988. ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
  989. /*
  990. compressBound() returns an upper bound on the compressed size after
  991. compress() or compress2() on sourceLen bytes. It would be used before a
  992. compress() or compress2() call to allocate the destination buffer.
  993. */
  994. ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
  995. const Bytef *source, uLong sourceLen));
  996. /*
  997. Decompresses the source buffer into the destination buffer. sourceLen is
  998. the byte length of the source buffer. Upon entry, destLen is the total size
  999. of the destination buffer, which must be large enough to hold the entire
  1000. uncompressed data. (The size of the uncompressed data must have been saved
  1001. previously by the compressor and transmitted to the decompressor by some
  1002. mechanism outside the scope of this compression library.) Upon exit, destLen
  1003. is the actual size of the uncompressed buffer.
  1004. uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
  1005. enough memory, Z_BUF_ERROR if there was not enough room in the output
  1006. buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
  1007. the case where there is not enough room, uncompress() will fill the output
  1008. buffer with the uncompressed data up to that point.
  1009. */
  1010. /* gzip file access functions */
  1011. /*
  1012. This library supports reading and writing files in gzip (.gz) format with
  1013. an interface similar to that of stdio, using the functions that start with
  1014. "gz". The gzip format is different from the zlib format. gzip is a gzip
  1015. wrapper, documented in RFC 1952, wrapped around a deflate stream.
  1016. */
  1017. typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
  1018. /*
  1019. ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
  1020. Opens a gzip (.gz) file for reading or writing. The mode parameter is as
  1021. in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
  1022. a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
  1023. compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
  1024. for fixed code compression as in "wb9F". (See the description of
  1025. deflateInit2 for more information about the strategy parameter.) 'T' will
  1026. request transparent writing or appending with no compression and not using
  1027. the gzip format.
  1028. "a" can be used instead of "w" to request that the gzip stream that will
  1029. be written be appended to the file. "+" will result in an error, since
  1030. reading and writing to the same gzip file is not supported. The addition of
  1031. "x" when writing will create the file exclusively, which fails if the file
  1032. already exists. On systems that support it, the addition of "e" when
  1033. reading or writing will set the flag to close the file on an execve() call.
  1034. These functions, as well as gzip, will read and decode a sequence of gzip
  1035. streams in a file. The append function of gzopen() can be used to create
  1036. such a file. (Also see gzflush() for another way to do this.) When
  1037. appending, gzopen does not test whether the file begins with a gzip stream,
  1038. nor does it look for the end of the gzip streams to begin appending. gzopen
  1039. will simply append a gzip stream to the existing file.
  1040. gzopen can be used to read a file which is not in gzip format; in this
  1041. case gzread will directly read from the file without decompression. When
  1042. reading, this will be detected automatically by looking for the magic two-
  1043. byte gzip header.
  1044. gzopen returns NULL if the file could not be opened, if there was
  1045. insufficient memory to allocate the gzFile state, or if an invalid mode was
  1046. specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
  1047. errno can be checked to determine if the reason gzopen failed was that the
  1048. file could not be opened.
  1049. */
  1050. ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
  1051. /*
  1052. gzdopen associates a gzFile with the file descriptor fd. File descriptors
  1053. are obtained from calls like open, dup, creat, pipe or fileno (if the file
  1054. has been previously opened with fopen). The mode parameter is as in gzopen.
  1055. The next call of gzclose on the returned gzFile will also close the file
  1056. descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
  1057. fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
  1058. mode);. The duplicated descriptor should be saved to avoid a leak, since
  1059. gzdopen does not close fd if it fails. If you are using fileno() to get the
  1060. file descriptor from a FILE *, then you will have to use dup() to avoid
  1061. double-close()ing the file descriptor. Both gzclose() and fclose() will
  1062. close the associated file descriptor, so they need to have different file
  1063. descriptors.
  1064. gzdopen returns NULL if there was insufficient memory to allocate the
  1065. gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
  1066. provided, or '+' was provided), or if fd is -1. The file descriptor is not
  1067. used until the next gz* read, write, seek, or close operation, so gzdopen
  1068. will not detect if fd is invalid (unless fd is -1).
  1069. */
  1070. ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
  1071. /*
  1072. Set the internal buffer size used by this library's functions. The
  1073. default buffer size is 8192 bytes. This function must be called after
  1074. gzopen() or gzdopen(), and before any other calls that read or write the
  1075. file. The buffer memory allocation is always deferred to the first read or
  1076. write. Two buffers are allocated, either both of the specified size when
  1077. writing, or one of the specified size and the other twice that size when
  1078. reading. A larger buffer size of, for example, 64K or 128K bytes will
  1079. noticeably increase the speed of decompression (reading).
  1080. The new buffer size also affects the maximum length for gzprintf().
  1081. gzbuffer() returns 0 on success, or -1 on failure, such as being called
  1082. too late.
  1083. */
  1084. ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
  1085. /*
  1086. Dynamically update the compression level or strategy. See the description
  1087. of deflateInit2 for the meaning of these parameters.
  1088. gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
  1089. opened for writing.
  1090. */
  1091. ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
  1092. /*
  1093. Reads the given number of uncompressed bytes from the compressed file. If
  1094. the input file is not in gzip format, gzread copies the given number of
  1095. bytes into the buffer directly from the file.
  1096. After reaching the end of a gzip stream in the input, gzread will continue
  1097. to read, looking for another gzip stream. Any number of gzip streams may be
  1098. concatenated in the input file, and will all be decompressed by gzread().
  1099. If something other than a gzip stream is encountered after a gzip stream,
  1100. that remaining trailing garbage is ignored (and no error is returned).
  1101. gzread can be used to read a gzip file that is being concurrently written.
  1102. Upon reaching the end of the input, gzread will return with the available
  1103. data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
  1104. gzclearerr can be used to clear the end of file indicator in order to permit
  1105. gzread to be tried again. Z_OK indicates that a gzip stream was completed
  1106. on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
  1107. middle of a gzip stream. Note that gzread does not return -1 in the event
  1108. of an incomplete gzip stream. This error is deferred until gzclose(), which
  1109. will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
  1110. stream. Alternatively, gzerror can be used before gzclose to detect this
  1111. case.
  1112. gzread returns the number of uncompressed bytes actually read, less than
  1113. len for end of file, or -1 for error.
  1114. */
  1115. ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
  1116. voidpc buf, unsigned len));
  1117. /*
  1118. Writes the given number of uncompressed bytes into the compressed file.
  1119. gzwrite returns the number of uncompressed bytes written or 0 in case of
  1120. error.
  1121. */
  1122. ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
  1123. /*
  1124. Converts, formats, and writes the arguments to the compressed file under
  1125. control of the format string, as in fprintf. gzprintf returns the number of
  1126. uncompressed bytes actually written, or 0 in case of error. The number of
  1127. uncompressed bytes written is limited to 8191, or one less than the buffer
  1128. size given to gzbuffer(). The caller should assure that this limit is not
  1129. exceeded. If it is exceeded, then gzprintf() will return an error (0) with
  1130. nothing written. In this case, there may also be a buffer overflow with
  1131. unpredictable consequences, which is possible only if zlib was compiled with
  1132. the insecure functions sprintf() or vsprintf() because the secure snprintf()
  1133. or vsnprintf() functions were not available. This can be determined using
  1134. zlibCompileFlags().
  1135. */
  1136. ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
  1137. /*
  1138. Writes the given null-terminated string to the compressed file, excluding
  1139. the terminating null character.
  1140. gzputs returns the number of characters written, or -1 in case of error.
  1141. */
  1142. ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
  1143. /*
  1144. Reads bytes from the compressed file until len-1 characters are read, or a
  1145. newline character is read and transferred to buf, or an end-of-file
  1146. condition is encountered. If any characters are read or if len == 1, the
  1147. string is terminated with a null character. If no characters are read due
  1148. to an end-of-file or len < 1, then the buffer is left untouched.
  1149. gzgets returns buf which is a null-terminated string, or it returns NULL
  1150. for end-of-file or in case of error. If there was an error, the contents at
  1151. buf are indeterminate.
  1152. */
  1153. ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
  1154. /*
  1155. Writes c, converted to an unsigned char, into the compressed file. gzputc
  1156. returns the value that was written, or -1 in case of error.
  1157. */
  1158. ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
  1159. /*
  1160. Reads one byte from the compressed file. gzgetc returns this byte or -1
  1161. in case of end of file or error. This is implemented as a macro for speed.
  1162. As such, it does not do all of the checking the other functions do. I.e.
  1163. it does not check to see if file is NULL, nor whether the structure file
  1164. points to has been clobbered or not.
  1165. */
  1166. ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
  1167. /*
  1168. Push one character back onto the stream to be read as the first character
  1169. on the next read. At least one character of push-back is allowed.
  1170. gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
  1171. fail if c is -1, and may fail if a character has been pushed but not read
  1172. yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
  1173. output buffer size of pushed characters is allowed. (See gzbuffer above.)
  1174. The pushed character will be discarded if the stream is repositioned with
  1175. gzseek() or gzrewind().
  1176. */
  1177. ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
  1178. /*
  1179. Flushes all pending output into the compressed file. The parameter flush
  1180. is as in the deflate() function. The return value is the zlib error number
  1181. (see function gzerror below). gzflush is only permitted when writing.
  1182. If the flush parameter is Z_FINISH, the remaining data is written and the
  1183. gzip stream is completed in the output. If gzwrite() is called again, a new
  1184. gzip stream will be started in the output. gzread() is able to read such
  1185. concatented gzip streams.
  1186. gzflush should be called only when strictly necessary because it will
  1187. degrade compression if called too often.
  1188. */
  1189. /*
  1190. ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
  1191. z_off_t offset, int whence));
  1192. Sets the starting position for the next gzread or gzwrite on the given
  1193. compressed file. The offset represents a number of bytes in the
  1194. uncompressed data stream. The whence parameter is defined as in lseek(2);
  1195. the value SEEK_END is not supported.
  1196. If the file is opened for reading, this function is emulated but can be
  1197. extremely slow. If the file is opened for writing, only forward seeks are
  1198. supported; gzseek then compresses a sequence of zeroes up to the new
  1199. starting position.
  1200. gzseek returns the resulting offset location as measured in bytes from
  1201. the beginning of the uncompressed stream, or -1 in case of error, in
  1202. particular if the file is opened for writing and the new starting position
  1203. would be before the current position.
  1204. */
  1205. ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
  1206. /*
  1207. Rewinds the given file. This function is supported only for reading.
  1208. gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
  1209. */
  1210. /*
  1211. ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
  1212. Returns the starting position for the next gzread or gzwrite on the given
  1213. compressed file. This position represents a number of bytes in the
  1214. uncompressed data stream, and is zero when starting, even if appending or
  1215. reading a gzip stream from the middle of a file using gzdopen().
  1216. gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
  1217. */
  1218. /*
  1219. ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
  1220. Returns the current offset in the file being read or written. This offset
  1221. includes the count of bytes that precede the gzip stream, for example when
  1222. appending or when using gzdopen() for reading. When reading, the offset
  1223. does not include as yet unused buffered input. This information can be used
  1224. for a progress indicator. On error, gzoffset() returns -1.
  1225. */
  1226. ZEXTERN int ZEXPORT gzeof OF((gzFile file));
  1227. /*
  1228. Returns true (1) if the end-of-file indicator has been set while reading,
  1229. false (0) otherwise. Note that the end-of-file indicator is set only if the
  1230. read tried to go past the end of the input, but came up short. Therefore,
  1231. just like feof(), gzeof() may return false even if there is no more data to
  1232. read, in the event that the last read request was for the exact number of
  1233. bytes remaining in the input file. This will happen if the input file size
  1234. is an exact multiple of the buffer size.
  1235. If gzeof() returns true, then the read functions will return no more data,
  1236. unless the end-of-file indicator is reset by gzclearerr() and the input file
  1237. has grown since the previous end of file was detected.
  1238. */
  1239. ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
  1240. /*
  1241. Returns true (1) if file is being copied directly while reading, or false
  1242. (0) if file is a gzip stream being decompressed.
  1243. If the input file is empty, gzdirect() will return true, since the input
  1244. does not contain a gzip stream.
  1245. If gzdirect() is used immediately after gzopen() or gzdopen() it will
  1246. cause buffers to be allocated to allow reading the file to determine if it
  1247. is a gzip file. Therefore if gzbuffer() is used, it should be called before
  1248. gzdirect().
  1249. When writing, gzdirect() returns true (1) if transparent writing was
  1250. requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
  1251. gzdirect() is not needed when writing. Transparent writing must be
  1252. explicitly requested, so the application already knows the answer. When
  1253. linking statically, using gzdirect() will include all of the zlib code for
  1254. gzip file reading and decompression, which may not be desired.)
  1255. */
  1256. ZEXTERN int ZEXPORT gzclose OF((gzFile file));
  1257. /*
  1258. Flushes all pending output if necessary, closes the compressed file and
  1259. deallocates the (de)compression state. Note that once file is closed, you
  1260. cannot call gzerror with file, since its structures have been deallocated.
  1261. gzclose must not be called more than once on the same file, just as free
  1262. must not be called more than once on the same allocation.
  1263. gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
  1264. file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
  1265. last read ended in the middle of a gzip stream, or Z_OK on success.
  1266. */
  1267. ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
  1268. ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
  1269. /*
  1270. Same as gzclose(), but gzclose_r() is only for use when reading, and
  1271. gzclose_w() is only for use when writing or appending. The advantage to
  1272. using these instead of gzclose() is that they avoid linking in zlib
  1273. compression or decompression code that is not used when only reading or only
  1274. writing respectively. If gzclose() is used, then both compression and
  1275. decompression code will be included the application when linking to a static
  1276. zlib library.
  1277. */
  1278. ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
  1279. /*
  1280. Returns the error message for the last error which occurred on the given
  1281. compressed file. errnum is set to zlib error number. If an error occurred
  1282. in the file system and not in the compression library, errnum is set to
  1283. Z_ERRNO and the application may consult errno to get the exact error code.
  1284. The application must not modify the returned string. Future calls to
  1285. this function may invalidate the previously returned string. If file is
  1286. closed, then the string previously returned by gzerror will no longer be
  1287. available.
  1288. gzerror() should be used to distinguish errors from end-of-file for those
  1289. functions above that do not distinguish those cases in their return values.
  1290. */
  1291. ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
  1292. /*
  1293. Clears the error and end-of-file flags for file. This is analogous to the
  1294. clearerr() function in stdio. This is useful for continuing to read a gzip
  1295. file that is being written concurrently.
  1296. */
  1297. #endif /* !Z_SOLO */
  1298. /* checksum functions */
  1299. /*
  1300. These functions are not related to compression but are exported
  1301. anyway because they might be useful in applications using the compression
  1302. library.
  1303. */
  1304. ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
  1305. /*
  1306. Update a running Adler-32 checksum with the bytes buf[0..len-1] and
  1307. return the updated checksum. If buf is Z_NULL, this function returns the
  1308. required initial value for the checksum.
  1309. An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
  1310. much faster.
  1311. Usage example:
  1312. uLong adler = adler32(0L, Z_NULL, 0);
  1313. while (read_buffer(buffer, length) != EOF) {
  1314. adler = adler32(adler, buffer, length);
  1315. }
  1316. if (adler != original_adler) error();
  1317. */
  1318. /*
  1319. ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
  1320. z_off_t len2));
  1321. Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
  1322. and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
  1323. each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
  1324. seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
  1325. that the z_off_t type (like off_t) is a signed integer. If len2 is
  1326. negative, the result has no meaning or utility.
  1327. */
  1328. ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
  1329. /*
  1330. Update a running CRC-32 with the bytes buf[0..len-1] and return the
  1331. updated CRC-32. If buf is Z_NULL, this function returns the required
  1332. initial value for the crc. Pre- and post-conditioning (one's complement) is
  1333. performed within this function so it shouldn't be done by the application.
  1334. Usage example:
  1335. uLong crc = crc32(0L, Z_NULL, 0);
  1336. while (read_buffer(buffer, length) != EOF) {
  1337. crc = crc32(crc, buffer, length);
  1338. }
  1339. if (crc != original_crc) error();
  1340. */
  1341. /*
  1342. ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
  1343. Combine two CRC-32 check values into one. For two sequences of bytes,
  1344. seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
  1345. calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
  1346. check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
  1347. len2.
  1348. */
  1349. /* various hacks, don't look :) */
  1350. /* deflateInit and inflateInit are macros to allow checking the zlib version
  1351. * and the compiler's view of z_stream:
  1352. */
  1353. ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
  1354. const char *version, int stream_size));
  1355. ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
  1356. const char *version, int stream_size));
  1357. ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
  1358. int windowBits, int memLevel,
  1359. int strategy, const char *version,
  1360. int stream_size));
  1361. ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
  1362. const char *version, int stream_size));
  1363. ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
  1364. unsigned char FAR *window,
  1365. const char *version,
  1366. int stream_size));
  1367. #define deflateInit(strm, level) \
  1368. deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
  1369. #define inflateInit(strm) \
  1370. inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
  1371. #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
  1372. deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
  1373. (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
  1374. #define inflateInit2(strm, windowBits) \
  1375. inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
  1376. (int)sizeof(z_stream))
  1377. #define inflateBackInit(strm, windowBits, window) \
  1378. inflateBackInit_((strm), (windowBits), (window), \
  1379. ZLIB_VERSION, (int)sizeof(z_stream))
  1380. #ifndef Z_SOLO
  1381. /* gzgetc() macro and its supporting function and exposed data structure. Note
  1382. * that the real internal state is much larger than the exposed structure.
  1383. * This abbreviated structure exposes just enough for the gzgetc() macro. The
  1384. * user should not mess with these exposed elements, since their names or
  1385. * behavior could change in the future, perhaps even capriciously. They can
  1386. * only be used by the gzgetc() macro. You have been warned.
  1387. */
  1388. struct gzFile_s {
  1389. unsigned have;
  1390. unsigned char *next;
  1391. z_off64_t pos;
  1392. };
  1393. ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
  1394. #ifdef Z_PREFIX_SET
  1395. # undef z_gzgetc
  1396. # define z_gzgetc(g) \
  1397. ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
  1398. #else
  1399. # define gzgetc(g) \
  1400. ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
  1401. #endif
  1402. /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
  1403. * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
  1404. * both are true, the application gets the *64 functions, and the regular
  1405. * functions are changed to 64 bits) -- in case these are set on systems
  1406. * without large file support, _LFS64_LARGEFILE must also be true
  1407. */
  1408. #ifdef Z_LARGE64
  1409. ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
  1410. ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
  1411. ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
  1412. ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
  1413. ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
  1414. ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
  1415. #endif
  1416. #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
  1417. # ifdef Z_PREFIX_SET
  1418. # define z_gzopen z_gzopen64
  1419. # define z_gzseek z_gzseek64
  1420. # define z_gztell z_gztell64
  1421. # define z_gzoffset z_gzoffset64
  1422. # define z_adler32_combine z_adler32_combine64
  1423. # define z_crc32_combine z_crc32_combine64
  1424. # else
  1425. # define gzopen gzopen64
  1426. # define gzseek gzseek64
  1427. # define gztell gztell64
  1428. # define gzoffset gzoffset64
  1429. # define adler32_combine adler32_combine64
  1430. # define crc32_combine crc32_combine64
  1431. # endif
  1432. # ifndef Z_LARGE64
  1433. ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
  1434. ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
  1435. ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
  1436. ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
  1437. ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
  1438. ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
  1439. # endif
  1440. #else
  1441. ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
  1442. ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
  1443. ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
  1444. ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
  1445. ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
  1446. ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
  1447. #endif
  1448. #else /* Z_SOLO */
  1449. ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
  1450. ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
  1451. #endif /* !Z_SOLO */
  1452. /* hack for buggy compilers */
  1453. #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
  1454. struct internal_state {int dummy;};
  1455. #endif
  1456. /* undocumented functions */
  1457. ZEXTERN const char * ZEXPORT zError OF((int));
  1458. ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp));
  1459. ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void));
  1460. ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int));
  1461. ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp));
  1462. ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp));
  1463. #if defined(_WIN32) && !defined(Z_SOLO)
  1464. ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path,
  1465. const char *mode));
  1466. #endif
  1467. #ifdef __cplusplus
  1468. }
  1469. #endif
  1470. #endif /* ZLIB_H */