/jcl/source/common/zlib.h

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  1. /* zlib.h -- interface of the 'zlib' general purpose compression library
  2. version 1.2.5, April 19th, 2010
  3. Copyright (C) 1995-2010 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://www.ietf.org/rfc/rfc1950.txt
  21. (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (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 "1.2.5"
  30. #define ZLIB_VERNUM 0x1250
  31. #define ZLIB_VER_MAJOR 1
  32. #define ZLIB_VER_MINOR 2
  33. #define ZLIB_VER_REVISION 5
  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. Bytef *next_in; /* next input byte */
  66. uInt avail_in; /* number of bytes available at next_in */
  67. uLong total_in; /* total nb 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 nb of bytes output so far */
  71. 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). If deflate does not return
  268. Z_STREAM_END, then it must be called again as described above.
  269. deflate() sets strm->adler to the adler32 checksum of all input read
  270. so far (that is, total_in bytes).
  271. deflate() may update strm->data_type if it can make a good guess about
  272. the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
  273. binary. This field is only for information purposes and does not affect the
  274. compression algorithm in any manner.
  275. deflate() returns Z_OK if some progress has been made (more input
  276. processed or more output produced), Z_STREAM_END if all input has been
  277. consumed and all output has been produced (only when flush is set to
  278. Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
  279. if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
  280. (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
  281. fatal, and deflate() can be called again with more input and more output
  282. space to continue compressing.
  283. */
  284. ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
  285. /*
  286. All dynamically allocated data structures for this stream are freed.
  287. This function discards any unprocessed input and does not flush any pending
  288. output.
  289. deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
  290. stream state was inconsistent, Z_DATA_ERROR if the stream was freed
  291. prematurely (some input or output was discarded). In the error case, msg
  292. may be set but then points to a static string (which must not be
  293. deallocated).
  294. */
  295. /*
  296. ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
  297. Initializes the internal stream state for decompression. The fields
  298. next_in, avail_in, zalloc, zfree and opaque must be initialized before by
  299. the caller. If next_in is not Z_NULL and avail_in is large enough (the
  300. exact value depends on the compression method), inflateInit determines the
  301. compression method from the zlib header and allocates all data structures
  302. accordingly; otherwise the allocation will be deferred to the first call of
  303. inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
  304. use default allocation functions.
  305. inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
  306. memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
  307. version assumed by the caller, or Z_STREAM_ERROR if the parameters are
  308. invalid, such as a null pointer to the structure. msg is set to null if
  309. there is no error message. inflateInit does not perform any decompression
  310. apart from possibly reading the zlib header if present: actual decompression
  311. will be done by inflate(). (So next_in and avail_in may be modified, but
  312. next_out and avail_out are unused and unchanged.) The current implementation
  313. of inflateInit() does not process any header information -- that is deferred
  314. until inflate() is called.
  315. */
  316. ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
  317. /*
  318. inflate decompresses as much data as possible, and stops when the input
  319. buffer becomes empty or the output buffer becomes full. It may introduce
  320. some output latency (reading input without producing any output) except when
  321. forced to flush.
  322. The detailed semantics are as follows. inflate performs one or both of the
  323. following actions:
  324. - Decompress more input starting at next_in and update next_in and avail_in
  325. accordingly. If not all input can be processed (because there is not
  326. enough room in the output buffer), next_in is updated and processing will
  327. resume at this point for the next call of inflate().
  328. - Provide more output starting at next_out and update next_out and avail_out
  329. accordingly. inflate() provides as much output as possible, until there is
  330. no more input data or no more space in the output buffer (see below about
  331. the flush parameter).
  332. Before the call of inflate(), the application should ensure that at least
  333. one of the actions is possible, by providing more input and/or consuming more
  334. output, and updating the next_* and avail_* values accordingly. The
  335. application can consume the uncompressed output when it wants, for example
  336. when the output buffer is full (avail_out == 0), or after each call of
  337. inflate(). If inflate returns Z_OK and with zero avail_out, it must be
  338. called again after making room in the output buffer because there might be
  339. more output pending.
  340. The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
  341. Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
  342. output as possible to the output buffer. Z_BLOCK requests that inflate()
  343. stop if and when it gets to the next deflate block boundary. When decoding
  344. the zlib or gzip format, this will cause inflate() to return immediately
  345. after the header and before the first block. When doing a raw inflate,
  346. inflate() will go ahead and process the first block, and will return when it
  347. gets to the end of that block, or when it runs out of data.
  348. The Z_BLOCK option assists in appending to or combining deflate streams.
  349. Also to assist in this, on return inflate() will set strm->data_type to the
  350. number of unused bits in the last byte taken from strm->next_in, plus 64 if
  351. inflate() is currently decoding the last block in the deflate stream, plus
  352. 128 if inflate() returned immediately after decoding an end-of-block code or
  353. decoding the complete header up to just before the first byte of the deflate
  354. stream. The end-of-block will not be indicated until all of the uncompressed
  355. data from that block has been written to strm->next_out. The number of
  356. unused bits may in general be greater than seven, except when bit 7 of
  357. data_type is set, in which case the number of unused bits will be less than
  358. eight. data_type is set as noted here every time inflate() returns for all
  359. flush options, and so can be used to determine the amount of currently
  360. consumed input in bits.
  361. The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
  362. end of each deflate block header is reached, before any actual data in that
  363. block is decoded. This allows the caller to determine the length of the
  364. deflate block header for later use in random access within a deflate block.
  365. 256 is added to the value of strm->data_type when inflate() returns
  366. immediately after reaching the end of the deflate block header.
  367. inflate() should normally be called until it returns Z_STREAM_END or an
  368. error. However if all decompression is to be performed in a single step (a
  369. single call of inflate), the parameter flush should be set to Z_FINISH. In
  370. this case all pending input is processed and all pending output is flushed;
  371. avail_out must be large enough to hold all the uncompressed data. (The size
  372. of the uncompressed data may have been saved by the compressor for this
  373. purpose.) The next operation on this stream must be inflateEnd to deallocate
  374. the decompression state. The use of Z_FINISH is never required, but can be
  375. used to inform inflate that a faster approach may be used for the single
  376. inflate() call.
  377. In this implementation, inflate() always flushes as much output as
  378. possible to the output buffer, and always uses the faster approach on the
  379. first call. So the only effect of the flush parameter in this implementation
  380. is on the return value of inflate(), as noted below, or when it returns early
  381. because Z_BLOCK or Z_TREES is used.
  382. If a preset dictionary is needed after this call (see inflateSetDictionary
  383. below), inflate sets strm->adler to the adler32 checksum of the dictionary
  384. chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
  385. strm->adler to the adler32 checksum of all output produced so far (that is,
  386. total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
  387. below. At the end of the stream, inflate() checks that its computed adler32
  388. checksum is equal to that saved by the compressor and returns Z_STREAM_END
  389. only if the checksum is correct.
  390. inflate() can decompress and check either zlib-wrapped or gzip-wrapped
  391. deflate data. The header type is detected automatically, if requested when
  392. initializing with inflateInit2(). Any information contained in the gzip
  393. header is not retained, so applications that need that information should
  394. instead use raw inflate, see inflateInit2() below, or inflateBack() and
  395. perform their own processing of the gzip header and trailer.
  396. inflate() returns Z_OK if some progress has been made (more input processed
  397. or more output produced), Z_STREAM_END if the end of the compressed data has
  398. been reached and all uncompressed output has been produced, Z_NEED_DICT if a
  399. preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
  400. corrupted (input stream not conforming to the zlib format or incorrect check
  401. value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
  402. next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
  403. Z_BUF_ERROR if no progress is possible or if there was not enough room in the
  404. output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
  405. inflate() can be called again with more input and more output space to
  406. continue decompressing. If Z_DATA_ERROR is returned, the application may
  407. then call inflateSync() to look for a good compression block if a partial
  408. recovery of the data is desired.
  409. */
  410. ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
  411. /*
  412. All dynamically allocated data structures for this stream are freed.
  413. This function discards any unprocessed input and does not flush any pending
  414. output.
  415. inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
  416. was inconsistent. In the error case, msg may be set but then points to a
  417. static string (which must not be deallocated).
  418. */
  419. /* Advanced functions */
  420. /*
  421. The following functions are needed only in some special applications.
  422. */
  423. /*
  424. ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
  425. int level,
  426. int method,
  427. int windowBits,
  428. int memLevel,
  429. int strategy));
  430. This is another version of deflateInit with more compression options. The
  431. fields next_in, zalloc, zfree and opaque must be initialized before by the
  432. caller.
  433. The method parameter is the compression method. It must be Z_DEFLATED in
  434. this version of the library.
  435. The windowBits parameter is the base two logarithm of the window size
  436. (the size of the history buffer). It should be in the range 8..15 for this
  437. version of the library. Larger values of this parameter result in better
  438. compression at the expense of memory usage. The default value is 15 if
  439. deflateInit is used instead.
  440. windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
  441. determines the window size. deflate() will then generate raw deflate data
  442. with no zlib header or trailer, and will not compute an adler32 check value.
  443. windowBits can also be greater than 15 for optional gzip encoding. Add
  444. 16 to windowBits to write a simple gzip header and trailer around the
  445. compressed data instead of a zlib wrapper. The gzip header will have no
  446. file name, no extra data, no comment, no modification time (set to zero), no
  447. header crc, and the operating system will be set to 255 (unknown). If a
  448. gzip stream is being written, strm->adler is a crc32 instead of an adler32.
  449. The memLevel parameter specifies how much memory should be allocated
  450. for the internal compression state. memLevel=1 uses minimum memory but is
  451. slow and reduces compression ratio; memLevel=9 uses maximum memory for
  452. optimal speed. The default value is 8. See zconf.h for total memory usage
  453. as a function of windowBits and memLevel.
  454. The strategy parameter is used to tune the compression algorithm. Use the
  455. value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
  456. filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
  457. string match), or Z_RLE to limit match distances to one (run-length
  458. encoding). Filtered data consists mostly of small values with a somewhat
  459. random distribution. In this case, the compression algorithm is tuned to
  460. compress them better. The effect of Z_FILTERED is to force more Huffman
  461. coding and less string matching; it is somewhat intermediate between
  462. Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
  463. fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
  464. strategy parameter only affects the compression ratio but not the
  465. correctness of the compressed output even if it is not set appropriately.
  466. Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
  467. decoder for special applications.
  468. deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  469. memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
  470. method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
  471. incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
  472. set to null if there is no error message. deflateInit2 does not perform any
  473. compression: this will be done by deflate().
  474. */
  475. ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
  476. const Bytef *dictionary,
  477. uInt dictLength));
  478. /*
  479. Initializes the compression dictionary from the given byte sequence
  480. without producing any compressed output. This function must be called
  481. immediately after deflateInit, deflateInit2 or deflateReset, before any call
  482. of deflate. The compressor and decompressor must use exactly the same
  483. dictionary (see inflateSetDictionary).
  484. The dictionary should consist of strings (byte sequences) that are likely
  485. to be encountered later in the data to be compressed, with the most commonly
  486. used strings preferably put towards the end of the dictionary. Using a
  487. dictionary is most useful when the data to be compressed is short and can be
  488. predicted with good accuracy; the data can then be compressed better than
  489. with the default empty dictionary.
  490. Depending on the size of the compression data structures selected by
  491. deflateInit or deflateInit2, a part of the dictionary may in effect be
  492. discarded, for example if the dictionary is larger than the window size
  493. provided in deflateInit or deflateInit2. Thus the strings most likely to be
  494. useful should be put at the end of the dictionary, not at the front. In
  495. addition, the current implementation of deflate will use at most the window
  496. size minus 262 bytes of the provided dictionary.
  497. Upon return of this function, strm->adler is set to the adler32 value
  498. of the dictionary; the decompressor may later use this value to determine
  499. which dictionary has been used by the compressor. (The adler32 value
  500. applies to the whole dictionary even if only a subset of the dictionary is
  501. actually used by the compressor.) If a raw deflate was requested, then the
  502. adler32 value is not computed and strm->adler is not set.
  503. deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
  504. parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
  505. inconsistent (for example if deflate has already been called for this stream
  506. or if the compression method is bsort). deflateSetDictionary does not
  507. perform any compression: this will be done by deflate().
  508. */
  509. ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
  510. z_streamp source));
  511. /*
  512. Sets the destination stream as a complete copy of the source stream.
  513. This function can be useful when several compression strategies will be
  514. tried, for example when there are several ways of pre-processing the input
  515. data with a filter. The streams that will be discarded should then be freed
  516. by calling deflateEnd. Note that deflateCopy duplicates the internal
  517. compression state which can be quite large, so this strategy is slow and can
  518. consume lots of memory.
  519. deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
  520. enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
  521. (such as zalloc being Z_NULL). msg is left unchanged in both source and
  522. destination.
  523. */
  524. ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
  525. /*
  526. This function is equivalent to deflateEnd followed by deflateInit,
  527. but does not free and reallocate all the internal compression state. The
  528. stream will keep the same compression level and any other attributes that
  529. may have been set by deflateInit2.
  530. deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  531. stream state was inconsistent (such as zalloc or state being Z_NULL).
  532. */
  533. ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
  534. int level,
  535. int strategy));
  536. /*
  537. Dynamically update the compression level and compression strategy. The
  538. interpretation of level and strategy is as in deflateInit2. This can be
  539. used to switch between compression and straight copy of the input data, or
  540. to switch to a different kind of input data requiring a different strategy.
  541. If the compression level is changed, the input available so far is
  542. compressed with the old level (and may be flushed); the new level will take
  543. effect only at the next call of deflate().
  544. Before the call of deflateParams, the stream state must be set as for
  545. a call of deflate(), since the currently available input may have to be
  546. compressed and flushed. In particular, strm->avail_out must be non-zero.
  547. deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
  548. stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
  549. strm->avail_out was zero.
  550. */
  551. ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
  552. int good_length,
  553. int max_lazy,
  554. int nice_length,
  555. int max_chain));
  556. /*
  557. Fine tune deflate's internal compression parameters. This should only be
  558. used by someone who understands the algorithm used by zlib's deflate for
  559. searching for the best matching string, and even then only by the most
  560. fanatic optimizer trying to squeeze out the last compressed bit for their
  561. specific input data. Read the deflate.c source code for the meaning of the
  562. max_lazy, good_length, nice_length, and max_chain parameters.
  563. deflateTune() can be called after deflateInit() or deflateInit2(), and
  564. returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
  565. */
  566. ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
  567. uLong sourceLen));
  568. /*
  569. deflateBound() returns an upper bound on the compressed size after
  570. deflation of sourceLen bytes. It must be called after deflateInit() or
  571. deflateInit2(), and after deflateSetHeader(), if used. This would be used
  572. to allocate an output buffer for deflation in a single pass, and so would be
  573. called before deflate().
  574. */
  575. ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
  576. int bits,
  577. int value));
  578. /*
  579. deflatePrime() inserts bits in the deflate output stream. The intent
  580. is that this function is used to start off the deflate output with the bits
  581. leftover from a previous deflate stream when appending to it. As such, this
  582. function can only be used for raw deflate, and must be used before the first
  583. deflate() call after a deflateInit2() or deflateReset(). bits must be less
  584. than or equal to 16, and that many of the least significant bits of value
  585. will be inserted in the output.
  586. deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
  587. stream state was inconsistent.
  588. */
  589. ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
  590. gz_headerp head));
  591. /*
  592. deflateSetHeader() provides gzip header information for when a gzip
  593. stream is requested by deflateInit2(). deflateSetHeader() may be called
  594. after deflateInit2() or deflateReset() and before the first call of
  595. deflate(). The text, time, os, extra field, name, and comment information
  596. in the provided gz_header structure are written to the gzip header (xflag is
  597. ignored -- the extra flags are set according to the compression level). The
  598. caller must assure that, if not Z_NULL, name and comment are terminated with
  599. a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
  600. available there. If hcrc is true, a gzip header crc is included. Note that
  601. the current versions of the command-line version of gzip (up through version
  602. 1.3.x) do not support header crc's, and will report that it is a "multi-part
  603. gzip file" and give up.
  604. If deflateSetHeader is not used, the default gzip header has text false,
  605. the time set to zero, and os set to 255, with no extra, name, or comment
  606. fields. The gzip header is returned to the default state by deflateReset().
  607. deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
  608. stream state was inconsistent.
  609. */
  610. /*
  611. ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
  612. int windowBits));
  613. This is another version of inflateInit with an extra parameter. The
  614. fields next_in, avail_in, zalloc, zfree and opaque must be initialized
  615. before by the caller.
  616. The windowBits parameter is the base two logarithm of the maximum window
  617. size (the size of the history buffer). It should be in the range 8..15 for
  618. this version of the library. The default value is 15 if inflateInit is used
  619. instead. windowBits must be greater than or equal to the windowBits value
  620. provided to deflateInit2() while compressing, or it must be equal to 15 if
  621. deflateInit2() was not used. If a compressed stream with a larger window
  622. size is given as input, inflate() will return with the error code
  623. Z_DATA_ERROR instead of trying to allocate a larger window.
  624. windowBits can also be zero to request that inflate use the window size in
  625. the zlib header of the compressed stream.
  626. windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
  627. determines the window size. inflate() will then process raw deflate data,
  628. not looking for a zlib or gzip header, not generating a check value, and not
  629. looking for any check values for comparison at the end of the stream. This
  630. is for use with other formats that use the deflate compressed data format
  631. such as zip. Those formats provide their own check values. If a custom
  632. format is developed using the raw deflate format for compressed data, it is
  633. recommended that a check value such as an adler32 or a crc32 be applied to
  634. the uncompressed data as is done in the zlib, gzip, and zip formats. For
  635. most applications, the zlib format should be used as is. Note that comments
  636. above on the use in deflateInit2() applies to the magnitude of windowBits.
  637. windowBits can also be greater than 15 for optional gzip decoding. Add
  638. 32 to windowBits to enable zlib and gzip decoding with automatic header
  639. detection, or add 16 to decode only the gzip format (the zlib format will
  640. return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
  641. crc32 instead of an adler32.
  642. inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
  643. memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
  644. version assumed by the caller, or Z_STREAM_ERROR if the parameters are
  645. invalid, such as a null pointer to the structure. msg is set to null if
  646. there is no error message. inflateInit2 does not perform any decompression
  647. apart from possibly reading the zlib header if present: actual decompression
  648. will be done by inflate(). (So next_in and avail_in may be modified, but
  649. next_out and avail_out are unused and unchanged.) The current implementation
  650. of inflateInit2() does not process any header information -- that is
  651. deferred until inflate() is called.
  652. */
  653. ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
  654. const Bytef *dictionary,
  655. uInt dictLength));
  656. /*
  657. Initializes the decompression dictionary from the given uncompressed byte
  658. sequence. This function must be called immediately after a call of inflate,
  659. if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
  660. can be determined from the adler32 value returned by that call of inflate.
  661. The compressor and decompressor must use exactly the same dictionary (see
  662. deflateSetDictionary). For raw inflate, this function can be called
  663. immediately after inflateInit2() or inflateReset() and before any call of
  664. inflate() to set the dictionary. The application must insure that the
  665. dictionary that was used for compression is provided.
  666. inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
  667. parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
  668. inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
  669. expected one (incorrect adler32 value). inflateSetDictionary does not
  670. perform any decompression: this will be done by subsequent calls of
  671. inflate().
  672. */
  673. ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
  674. /*
  675. Skips invalid compressed data until a full flush point (see above the
  676. description of deflate with Z_FULL_FLUSH) can be found, or until all
  677. available input is skipped. No output is provided.
  678. inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
  679. if no more input was provided, Z_DATA_ERROR if no flush point has been
  680. found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the
  681. success case, the application may save the current current value of total_in
  682. which indicates where valid compressed data was found. In the error case,
  683. the application may repeatedly call inflateSync, providing more input each
  684. time, until success or end of the input data.
  685. */
  686. ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
  687. z_streamp source));
  688. /*
  689. Sets the destination stream as a complete copy of the source stream.
  690. This function can be useful when randomly accessing a large stream. The
  691. first pass through the stream can periodically record the inflate state,
  692. allowing restarting inflate at those points when randomly accessing the
  693. stream.
  694. inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
  695. enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
  696. (such as zalloc being Z_NULL). msg is left unchanged in both source and
  697. destination.
  698. */
  699. ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
  700. /*
  701. This function is equivalent to inflateEnd followed by inflateInit,
  702. but does not free and reallocate all the internal decompression state. The
  703. stream will keep attributes that may have been set by inflateInit2.
  704. inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
  705. stream state was inconsistent (such as zalloc or state being Z_NULL).
  706. */
  707. ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
  708. int windowBits));
  709. /*
  710. This function is the same as inflateReset, but it also permits changing
  711. the wrap and window size requests. The windowBits parameter is interpreted
  712. the same as it is for inflateInit2.
  713. inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
  714. stream state was inconsistent (such as zalloc or state being Z_NULL), or if
  715. the windowBits parameter is invalid.
  716. */
  717. ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
  718. int bits,
  719. int value));
  720. /*
  721. This function inserts bits in the inflate input stream. The intent is
  722. that this function is used to start inflating at a bit position in the
  723. middle of a byte. The provided bits will be used before any bytes are used
  724. from next_in. This function should only be used with raw inflate, and
  725. should be used before the first inflate() call after inflateInit2() or
  726. inflateReset(). bits must be less than or equal to 16, and that many of the
  727. least significant bits of value will be inserted in the input.
  728. If bits is negative, then the input stream bit buffer is emptied. Then
  729. inflatePrime() can be called again to put bits in the buffer. This is used
  730. to clear out bits leftover after feeding inflate a block description prior
  731. to feeding inflate codes.
  732. inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
  733. stream state was inconsistent.
  734. */
  735. ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
  736. /*
  737. This function returns two values, one in the lower 16 bits of the return
  738. value, and the other in the remaining upper bits, obtained by shifting the
  739. return value down 16 bits. If the upper value is -1 and the lower value is
  740. zero, then inflate() is currently decoding information outside of a block.
  741. If the upper value is -1 and the lower value is non-zero, then inflate is in
  742. the middle of a stored block, with the lower value equaling the number of
  743. bytes from the input remaining to copy. If the upper value is not -1, then
  744. it is the number of bits back from the current bit position in the input of
  745. the code (literal or length/distance pair) currently being processed. In
  746. that case the lower value is the number of bytes already emitted for that
  747. code.
  748. A code is being processed if inflate is waiting for more input to complete
  749. decoding of the code, or if it has completed decoding but is waiting for
  750. more output space to write the literal or match data.
  751. inflateMark() is used to mark locations in the input data for random
  752. access, which may be at bit positions, and to note those cases where the
  753. output of a code may span boundaries of random access blocks. The current
  754. location in the input stream can be determined from avail_in and data_type
  755. as noted in the description for the Z_BLOCK flush parameter for inflate.
  756. inflateMark returns the value noted above or -1 << 16 if the provided
  757. source stream state was inconsistent.
  758. */
  759. ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
  760. gz_headerp head));
  761. /*
  762. inflateGetHeader() requests that gzip header information be stored in the
  763. provided gz_header structure. inflateGetHeader() may be called after
  764. inflateInit2() or inflateReset(), and before the first call of inflate().
  765. As inflate() processes the gzip stream, head->done is zero until the header
  766. is completed, at which time head->done is set to one. If a zlib stream is
  767. being decoded, then head->done is set to -1 to indicate that there will be
  768. no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
  769. used to force inflate() to return immediately after header processing is
  770. complete and before any actual data is decompressed.
  771. The text, time, xflags, and os fields are filled in with the gzip header
  772. contents. hcrc is set to true if there is a header CRC. (The header CRC
  773. was valid if done is set to one.) If extra is not Z_NULL, then extra_max
  774. contains the maximum number of bytes to write to extra. Once done is true,
  775. extra_len contains the actual extra field length, and extra contains the
  776. extra field, or that field truncated if extra_max is less than extra_len.
  777. If name is not Z_NULL, then up to name_max characters are written there,
  778. terminated with a zero unless the length is greater than name_max. If
  779. comment is not Z_NULL, then up to comm_max characters are written there,
  780. terminated with a zero unless the length is greater than comm_max. When any
  781. of extra, name, or comment are not Z_NULL and the respective field is not
  782. present in the header, then that field is set to Z_NULL to signal its
  783. absence. This allows the use of deflateSetHeader() with the returned
  784. structure to duplicate the header. However if those fields are set to
  785. allocated memory, then the application will need to save those pointers
  786. elsewhere so that they can be eventually freed.
  787. If inflateGetHeader is not used, then the header information is simply
  788. discarded. The header is always checked for validity, including the header
  789. CRC if present. inflateReset() will reset the process to discard the header
  790. information. The application would need to call inflateGetHeader() again to
  791. retrieve the header from the next gzip stream.
  792. inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
  793. stream state was inconsistent.
  794. */
  795. /*
  796. ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
  797. unsigned char FAR *window));
  798. Initialize the internal stream state for decompression using inflateBack()
  799. calls. The fields zalloc, zfree and opaque in strm must be initialized
  800. before the call. If zalloc and zfree are Z_NULL, then the default library-
  801. derived memory allocation routines are used. windowBits is the base two
  802. logarithm of the window size, in the range 8..15. window is a caller
  803. supplied buffer of that size. Except for special applications where it is
  804. assured that deflate was used with small window sizes, windowBits must be 15
  805. and a 32K byte window must be supplied to be able to decompress general
  806. deflate streams.
  807. See inflateBack() for the usage of these routines.
  808. inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
  809. the paramaters are invalid, Z_MEM_ERROR if the internal state could not be
  810. allocated, or Z_VERSION_ERROR if the version of the library does not match
  811. the version of the header file.
  812. */
  813. typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
  814. typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
  815. ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,