1 /* zlib.h -- interface of the 'zlib' general purpose compression library
   2   version 1.2.8, April 28th, 2013
   3 
   4   Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
   5 
   6   This software is provided 'as-is', without any express or implied
   7   warranty.  In no event will the authors be held liable for any damages
   8   arising from the use of this software.
   9 
  10   Permission is granted to anyone to use this software for any purpose,
  11   including commercial applications, and to alter it and redistribute it
  12   freely, subject to the following restrictions:
  13 
  14   1. The origin of this software must not be misrepresented; you must not
  15      claim that you wrote the original software. If you use this software
  16      in a product, an acknowledgment in the product documentation would be
  17      appreciated but is not required.
  18   2. Altered source versions must be plainly marked as such, and must not be
  19      misrepresented as being the original software.
  20   3. This notice may not be removed or altered from any source distribution.
  21 
  22   Jean-loup Gailly        Mark Adler
  23   jloup@gzip.org          madler@alumni.caltech.edu
  24 
  25 
  26   The data format used by the zlib library is described by RFCs (Request for
  27   Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
  28   (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
  29 */
  30 
  31 #ifndef ZLIB_H
  32 #define ZLIB_H
  33 
  34 #include "zconf.h"
  35 
  36 #ifdef __cplusplus
  37 extern "C" {
  38 #endif
  39 
  40 #define ZLIB_VERSION "1.2.8-T4mods"
  41 #define ZLIB_VERNUM 0x128f
  42 #define ZLIB_VER_MAJOR 1
  43 #define ZLIB_VER_MINOR 2
  44 #define ZLIB_VER_REVISION 8
  45 #define ZLIB_VER_SUBREVISION 0
  46 
  47 /*
  48     The 'zlib' compression library provides in-memory compression and
  49   decompression functions, including integrity checks of the uncompressed data.
  50   This version of the library supports only one compression method (deflation)
  51   but other algorithms will be added later and will have the same stream
  52   interface.
  53 
  54     Compression can be done in a single step if the buffers are large enough,
  55   or can be done by repeated calls of the compression function.  In the latter
  56   case, the application must provide more input and/or consume the output
  57   (providing more output space) before each call.
  58 
  59     The compressed data format used by default by the in-memory functions is
  60   the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
  61   around a deflate stream, which is itself documented in RFC 1951.
  62 
  63     The library also supports reading and writing files in gzip (.gz) format
  64   with an interface similar to that of stdio using the functions that start
  65   with "gz".  The gzip format is different from the zlib format.  gzip is a
  66   gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
  67 
  68     This library can optionally read and write gzip streams in memory as well.
  69 
  70     The zlib format was designed to be compact and fast for use in memory
  71   and on communications channels.  The gzip format was designed for single-
  72   file compression on file systems, has a larger header than zlib to maintain
  73   directory information, and uses a different, slower check method than zlib.
  74 
  75     The library does not install any signal handler.  The decoder checks
  76   the consistency of the compressed data, so the library should never crash
  77   even in case of corrupted input.
  78 */
  79 
  80 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
  81 typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
  82 
  83 struct internal_state;
  84 
  85 typedef struct z_stream_s {
  86     z_const Bytef *next_in;     /* next input byte */
  87     uInt     avail_in;  /* number of bytes available at next_in */
  88     uLong    total_in;  /* total number of input bytes read so far */
  89 
  90     Bytef    *next_out; /* next output byte should be put there */
  91     uInt     avail_out; /* remaining free space at next_out */
  92     uLong    total_out; /* total number of bytes output so far */
  93 
  94     z_const char *msg;  /* last error message, NULL if no error */
  95     struct internal_state FAR *state; /* not visible by applications */
  96 
  97     alloc_func zalloc;  /* used to allocate the internal state */
  98     free_func  zfree;   /* used to free the internal state */
  99     voidpf     opaque;  /* private data object passed to zalloc and zfree */
 100 
 101     int     data_type;  /* best guess about the data type: binary or text */
 102     uLong   adler;      /* adler32 value of the uncompressed data */
 103     uLong   reserved;   /* reserved for future use */
 104 } z_stream;
 105 
 106 typedef z_stream FAR *z_streamp;
 107 
 108 /*
 109      gzip header information passed to and from zlib routines.  See RFC 1952
 110   for more details on the meanings of these fields.
 111 */
 112 typedef struct gz_header_s {
 113     int     text;       /* true if compressed data believed to be text */
 114     uLong   time;       /* modification time */
 115     int     xflags;     /* extra flags (not used when writing a gzip file) */
 116     int     os;         /* operating system */
 117     Bytef   *extra;     /* pointer to extra field or Z_NULL if none */
 118     uInt    extra_len;  /* extra field length (valid if extra != Z_NULL) */
 119     uInt    extra_max;  /* space at extra (only when reading header) */
 120     Bytef   *name;      /* pointer to zero-terminated file name or Z_NULL */
 121     uInt    name_max;   /* space at name (only when reading header) */
 122     Bytef   *comment;   /* pointer to zero-terminated comment or Z_NULL */
 123     uInt    comm_max;   /* space at comment (only when reading header) */
 124     int     hcrc;       /* true if there was or will be a header crc */
 125     int     done;       /* true when done reading gzip header (not used
 126                            when writing a gzip file) */
 127 } gz_header;
 128 
 129 typedef gz_header FAR *gz_headerp;
 130 
 131 /*
 132      The application must update next_in and avail_in when avail_in has dropped
 133    to zero.  It must update next_out and avail_out when avail_out has dropped
 134    to zero.  The application must initialize zalloc, zfree and opaque before
 135    calling the init function.  All other fields are set by the compression
 136    library and must not be updated by the application.
 137 
 138      The opaque value provided by the application will be passed as the first
 139    parameter for calls of zalloc and zfree.  This can be useful for custom
 140    memory management.  The compression library attaches no meaning to the
 141    opaque value.
 142 
 143      zalloc must return Z_NULL if there is not enough memory for the object.
 144    If zlib is used in a multi-threaded application, zalloc and zfree must be
 145    thread safe.
 146 
 147      On 16-bit systems, the functions zalloc and zfree must be able to allocate
 148    exactly 65536 bytes, but will not be required to allocate more than this if
 149    the symbol MAXSEG_64K is defined (see zconf.h).  WARNING: On MSDOS, pointers
 150    returned by zalloc for objects of exactly 65536 bytes *must* have their
 151    offset normalized to zero.  The default allocation function provided by this
 152    library ensures this (see zutil.c).  To reduce memory requirements and avoid
 153    any allocation of 64K objects, at the expense of compression ratio, compile
 154    the library with -DMAX_WBITS=14 (see zconf.h).
 155 
 156      The fields total_in and total_out can be used for statistics or progress
 157    reports.  After compression, total_in holds the total size of the
 158    uncompressed data and may be saved for use in the decompressor (particularly
 159    if the decompressor wants to decompress everything in a single step).
 160 */
 161 
 162                         /* constants */
 163 
 164 #define Z_NO_FLUSH      0
 165 #define Z_PARTIAL_FLUSH 1
 166 #define Z_SYNC_FLUSH    2
 167 #define Z_FULL_FLUSH    3
 168 #define Z_FINISH        4
 169 #define Z_BLOCK         5
 170 #define Z_TREES         6
 171 /* Allowed flush values; see deflate() and inflate() below for details */
 172 
 173 #define Z_OK            0
 174 #define Z_STREAM_END    1
 175 #define Z_NEED_DICT     2
 176 #define Z_ERRNO        (-1)
 177 #define Z_STREAM_ERROR (-2)
 178 #define Z_DATA_ERROR   (-3)
 179 #define Z_MEM_ERROR    (-4)
 180 #define Z_BUF_ERROR    (-5)
 181 #define Z_VERSION_ERROR (-6)
 182 /* Return codes for the compression/decompression functions. Negative values
 183  * are errors, positive values are used for special but normal events.
 184  */
 185 
 186 #define Z_NO_COMPRESSION         0
 187 #define Z_BEST_SPEED             1
 188 #define Z_BEST_COMPRESSION       9
 189 #define Z_DEFAULT_COMPRESSION  (-1)
 190 /* compression levels */
 191 
 192 #define Z_FILTERED            1
 193 #define Z_HUFFMAN_ONLY        2
 194 #define Z_RLE                 3
 195 #define Z_FIXED               4
 196 #define Z_DEFAULT_STRATEGY    0
 197 /* compression strategy; see deflateInit2() below for details */
 198 
 199 #define Z_BINARY   0
 200 #define Z_TEXT     1
 201 #define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
 202 #define Z_UNKNOWN  2
 203 /* Possible values of the data_type field (though see inflate()) */
 204 
 205 #define Z_DEFLATED   8
 206 /* The deflate compression method (the only one supported in this version) */
 207 
 208 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
 209 
 210 #define zlib_version zlibVersion()
 211 /* for compatibility with versions < 1.0.2 */
 212 
 213 
 214                         /* basic functions */
 215 
 216 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
 217 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
 218    If the first character differs, the library code actually used is not
 219    compatible with the zlib.h header file used by the application.  This check
 220    is automatically made by deflateInit and inflateInit.
 221  */
 222 
 223 /*
 224 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
 225 
 226      Initializes the internal stream state for compression.  The fields
 227    zalloc, zfree and opaque must be initialized before by the caller.  If
 228    zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
 229    allocation functions.
 230 
 231      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
 232    1 gives best speed, 9 gives best compression, 0 gives no compression at all
 233    (the input data is simply copied a block at a time).  Z_DEFAULT_COMPRESSION
 234    requests a default compromise between speed and compression (currently
 235    equivalent to level 6).
 236 
 237      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
 238    memory, Z_STREAM_ERROR if level is not a valid compression level, or
 239    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
 240    with the version assumed by the caller (ZLIB_VERSION).  msg is set to null
 241    if there is no error message.  deflateInit does not perform any compression:
 242    this will be done by deflate().
 243 */
 244 
 245 
 246 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
 247 /*
 248     deflate compresses as much data as possible, and stops when the input
 249   buffer becomes empty or the output buffer becomes full.  It may introduce
 250   some output latency (reading input without producing any output) except when
 251   forced to flush.
 252 
 253     The detailed semantics are as follows.  deflate performs one or both of the
 254   following actions:
 255 
 256   - Compress more input starting at next_in and update next_in and avail_in
 257     accordingly.  If not all input can be processed (because there is not
 258     enough room in the output buffer), next_in and avail_in are updated and
 259     processing will resume at this point for the next call of deflate().
 260 
 261   - Provide more output starting at next_out and update next_out and avail_out
 262     accordingly.  This action is forced if the parameter flush is non zero.
 263     Forcing flush frequently degrades the compression ratio, so this parameter
 264     should be set only when necessary (in interactive applications).  Some
 265     output may be provided even if flush is not set.
 266 
 267     Before the call of deflate(), the application should ensure that at least
 268   one of the actions is possible, by providing more input and/or consuming more
 269   output, and updating avail_in or avail_out accordingly; avail_out should
 270   never be zero before the call.  The application can consume the compressed
 271   output when it wants, for example when the output buffer is full (avail_out
 272   == 0), or after each call of deflate().  If deflate returns Z_OK and with
 273   zero avail_out, it must be called again after making room in the output
 274   buffer because there might be more output pending.
 275 
 276     Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
 277   decide how much data to accumulate before producing output, in order to
 278   maximize compression.
 279 
 280     If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
 281   flushed to the output buffer and the output is aligned on a byte boundary, so
 282   that the decompressor can get all input data available so far.  (In
 283   particular avail_in is zero after the call if enough output space has been
 284   provided before the call.) Flushing may degrade compression for some
 285   compression algorithms and so it should be used only when necessary.  This
 286   completes the current deflate block and follows it with an empty stored block
 287   that is three bits plus filler bits to the next byte, followed by four bytes
 288   (00 00 ff ff).
 289 
 290     If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
 291   output buffer, but the output is not aligned to a byte boundary.  All of the
 292   input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
 293   This completes the current deflate block and follows it with an empty fixed
 294   codes block that is 10 bits long.  This assures that enough bytes are output
 295   in order for the decompressor to finish the block before the empty fixed code
 296   block.
 297 
 298     If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
 299   for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
 300   seven bits of the current block are held to be written as the next byte after
 301   the next deflate block is completed.  In this case, the decompressor may not
 302   be provided enough bits at this point in order to complete decompression of
 303   the data provided so far to the compressor.  It may need to wait for the next
 304   block to be emitted.  This is for advanced applications that need to control
 305   the emission of deflate blocks.
 306 
 307     If flush is set to Z_FULL_FLUSH, all output is flushed as with
 308   Z_SYNC_FLUSH, and the compression state is reset so that decompression can
 309   restart from this point if previous compressed data has been damaged or if
 310   random access is desired.  Using Z_FULL_FLUSH too often can seriously degrade
 311   compression.
 312 
 313     If deflate returns with avail_out == 0, this function must be called again
 314   with the same value of the flush parameter and more output space (updated
 315   avail_out), until the flush is complete (deflate returns with non-zero
 316   avail_out).  In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
 317   avail_out is greater than six to avoid repeated flush markers due to
 318   avail_out == 0 on return.
 319 
 320     If the parameter flush is set to Z_FINISH, pending input is processed,
 321   pending output is flushed and deflate returns with Z_STREAM_END if there was
 322   enough output space; if deflate returns with Z_OK, this function must be
 323   called again with Z_FINISH and more output space (updated avail_out) but no
 324   more input data, until it returns with Z_STREAM_END or an error.  After
 325   deflate has returned Z_STREAM_END, the only possible operations on the stream
 326   are deflateReset or deflateEnd.
 327 
 328     Z_FINISH can be used immediately after deflateInit if all the compression
 329   is to be done in a single step.  In this case, avail_out must be at least the
 330   value returned by deflateBound (see below).  Then deflate is guaranteed to
 331   return Z_STREAM_END.  If not enough output space is provided, deflate will
 332   not return Z_STREAM_END, and it must be called again as described above.
 333 
 334     deflate() sets strm->adler to the adler32 checksum of all input read
 335   so far (that is, total_in bytes).
 336 
 337     deflate() may update strm->data_type if it can make a good guess about
 338   the input data type (Z_BINARY or Z_TEXT).  In doubt, the data is considered
 339   binary.  This field is only for information purposes and does not affect the
 340   compression algorithm in any manner.
 341 
 342     deflate() returns Z_OK if some progress has been made (more input
 343   processed or more output produced), Z_STREAM_END if all input has been
 344   consumed and all output has been produced (only when flush is set to
 345   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
 346   if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
 347   (for example avail_in or avail_out was zero).  Note that Z_BUF_ERROR is not
 348   fatal, and deflate() can be called again with more input and more output
 349   space to continue compressing.
 350 */
 351 
 352 
 353 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
 354 /*
 355      All dynamically allocated data structures for this stream are freed.
 356    This function discards any unprocessed input and does not flush any pending
 357    output.
 358 
 359      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
 360    stream state was inconsistent, Z_DATA_ERROR if the stream was freed
 361    prematurely (some input or output was discarded).  In the error case, msg
 362    may be set but then points to a static string (which must not be
 363    deallocated).
 364 */
 365 
 366 
 367 /*
 368 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
 369 
 370      Initializes the internal stream state for decompression.  The fields
 371    next_in, avail_in, zalloc, zfree and opaque must be initialized before by
 372    the caller.  If next_in is not Z_NULL and avail_in is large enough (the
 373    exact value depends on the compression method), inflateInit determines the
 374    compression method from the zlib header and allocates all data structures
 375    accordingly; otherwise the allocation will be deferred to the first call of
 376    inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
 377    use default allocation functions.
 378 
 379      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
 380    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
 381    version assumed by the caller, or Z_STREAM_ERROR if the parameters are
 382    invalid, such as a null pointer to the structure.  msg is set to null if
 383    there is no error message.  inflateInit does not perform any decompression
 384    apart from possibly reading the zlib header if present: actual decompression
 385    will be done by inflate().  (So next_in and avail_in may be modified, but
 386    next_out and avail_out are unused and unchanged.) The current implementation
 387    of inflateInit() does not process any header information -- that is deferred
 388    until inflate() is called.
 389 */
 390 
 391 
 392 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
 393 /*
 394     inflate decompresses as much data as possible, and stops when the input
 395   buffer becomes empty or the output buffer becomes full.  It may introduce
 396   some output latency (reading input without producing any output) except when
 397   forced to flush.
 398 
 399   The detailed semantics are as follows.  inflate performs one or both of the
 400   following actions:
 401 
 402   - Decompress more input starting at next_in and update next_in and avail_in
 403     accordingly.  If not all input can be processed (because there is not
 404     enough room in the output buffer), next_in is updated and processing will
 405     resume at this point for the next call of inflate().
 406 
 407   - Provide more output starting at next_out and update next_out and avail_out
 408     accordingly.  inflate() provides as much output as possible, until there is
 409     no more input data or no more space in the output buffer (see below about
 410     the flush parameter).
 411 
 412     Before the call of inflate(), the application should ensure that at least
 413   one of the actions is possible, by providing more input and/or consuming more
 414   output, and updating the next_* and avail_* values accordingly.  The
 415   application can consume the uncompressed output when it wants, for example
 416   when the output buffer is full (avail_out == 0), or after each call of
 417   inflate().  If inflate returns Z_OK and with zero avail_out, it must be
 418   called again after making room in the output buffer because there might be
 419   more output pending.
 420 
 421     The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
 422   Z_BLOCK, or Z_TREES.  Z_SYNC_FLUSH requests that inflate() flush as much
 423   output as possible to the output buffer.  Z_BLOCK requests that inflate()
 424   stop if and when it gets to the next deflate block boundary.  When decoding
 425   the zlib or gzip format, this will cause inflate() to return immediately
 426   after the header and before the first block.  When doing a raw inflate,
 427   inflate() will go ahead and process the first block, and will return when it
 428   gets to the end of that block, or when it runs out of data.
 429 
 430     The Z_BLOCK option assists in appending to or combining deflate streams.
 431   Also to assist in this, on return inflate() will set strm->data_type to the
 432   number of unused bits in the last byte taken from strm->next_in, plus 64 if
 433   inflate() is currently decoding the last block in the deflate stream, plus
 434   128 if inflate() returned immediately after decoding an end-of-block code or
 435   decoding the complete header up to just before the first byte of the deflate
 436   stream.  The end-of-block will not be indicated until all of the uncompressed
 437   data from that block has been written to strm->next_out.  The number of
 438   unused bits may in general be greater than seven, except when bit 7 of
 439   data_type is set, in which case the number of unused bits will be less than
 440   eight.  data_type is set as noted here every time inflate() returns for all
 441   flush options, and so can be used to determine the amount of currently
 442   consumed input in bits.
 443 
 444     The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
 445   end of each deflate block header is reached, before any actual data in that
 446   block is decoded.  This allows the caller to determine the length of the
 447   deflate block header for later use in random access within a deflate block.
 448   256 is added to the value of strm->data_type when inflate() returns
 449   immediately after reaching the end of the deflate block header.
 450 
 451     inflate() should normally be called until it returns Z_STREAM_END or an
 452   error.  However if all decompression is to be performed in a single step (a
 453   single call of inflate), the parameter flush should be set to Z_FINISH.  In
 454   this case all pending input is processed and all pending output is flushed;
 455   avail_out must be large enough to hold all of the uncompressed data for the
 456   operation to complete.  (The size of the uncompressed data may have been
 457   saved by the compressor for this purpose.) The use of Z_FINISH is not
 458   required to perform an inflation in one step.  However it may be used to
 459   inform inflate that a faster approach can be used for the single inflate()
 460   call.  Z_FINISH also informs inflate to not maintain a sliding window if the
 461   stream completes, which reduces inflate's memory footprint.  If the stream
 462   does not complete, either because not all of the stream is provided or not
 463   enough output space is provided, then a sliding window will be allocated and
 464   inflate() can be called again to continue the operation as if Z_NO_FLUSH had
 465   been used.
 466 
 467      In this implementation, inflate() always flushes as much output as
 468   possible to the output buffer, and always uses the faster approach on the
 469   first call.  So the effects of the flush parameter in this implementation are
 470   on the return value of inflate() as noted below, when inflate() returns early
 471   when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
 472   memory for a sliding window when Z_FINISH is used.
 473 
 474      If a preset dictionary is needed after this call (see inflateSetDictionary
 475   below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
 476   chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
 477   strm->adler to the Adler-32 checksum of all output produced so far (that is,
 478   total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
 479   below.  At the end of the stream, inflate() checks that its computed adler32
 480   checksum is equal to that saved by the compressor and returns Z_STREAM_END
 481   only if the checksum is correct.
 482 
 483     inflate() can decompress and check either zlib-wrapped or gzip-wrapped
 484   deflate data.  The header type is detected automatically, if requested when
 485   initializing with inflateInit2().  Any information contained in the gzip
 486   header is not retained, so applications that need that information should
 487   instead use raw inflate, see inflateInit2() below, or inflateBack() and
 488   perform their own processing of the gzip header and trailer.  When processing
 489   gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
 490   producted so far.  The CRC-32 is checked against the gzip trailer.
 491 
 492     inflate() returns Z_OK if some progress has been made (more input processed
 493   or more output produced), Z_STREAM_END if the end of the compressed data has
 494   been reached and all uncompressed output has been produced, Z_NEED_DICT if a
 495   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
 496   corrupted (input stream not conforming to the zlib format or incorrect check
 497   value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
 498   next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
 499   Z_BUF_ERROR if no progress is possible or if there was not enough room in the
 500   output buffer when Z_FINISH is used.  Note that Z_BUF_ERROR is not fatal, and
 501   inflate() can be called again with more input and more output space to
 502   continue decompressing.  If Z_DATA_ERROR is returned, the application may
 503   then call inflateSync() to look for a good compression block if a partial
 504   recovery of the data is desired.
 505 */
 506 
 507 
 508 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
 509 /*
 510      All dynamically allocated data structures for this stream are freed.
 511    This function discards any unprocessed input and does not flush any pending
 512    output.
 513 
 514      inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
 515    was inconsistent.  In the error case, msg may be set but then points to a
 516    static string (which must not be deallocated).
 517 */
 518 
 519 
 520                         /* Advanced functions */
 521 
 522 /*
 523     The following functions are needed only in some special applications.
 524 */
 525 
 526 /*
 527 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
 528                                      int  level,
 529                                      int  method,
 530                                      int  windowBits,
 531                                      int  memLevel,
 532                                      int  strategy));
 533 
 534      This is another version of deflateInit with more compression options.  The
 535    fields next_in, zalloc, zfree and opaque must be initialized before by the
 536    caller.
 537 
 538      The method parameter is the compression method.  It must be Z_DEFLATED in
 539    this version of the library.
 540 
 541      The windowBits parameter is the base two logarithm of the window size
 542    (the size of the history buffer).  It should be in the range 8..15 for this
 543    version of the library.  Larger values of this parameter result in better
 544    compression at the expense of memory usage.  The default value is 15 if
 545    deflateInit is used instead.
 546 
 547      windowBits can also be -8..-15 for raw deflate.  In this case, -windowBits
 548    determines the window size.  deflate() will then generate raw deflate data
 549    with no zlib header or trailer, and will not compute an adler32 check value.
 550 
 551      windowBits can also be greater than 15 for optional gzip encoding.  Add
 552    16 to windowBits to write a simple gzip header and trailer around the
 553    compressed data instead of a zlib wrapper.  The gzip header will have no
 554    file name, no extra data, no comment, no modification time (set to zero), no
 555    header crc, and the operating system will be set to 255 (unknown).  If a
 556    gzip stream is being written, strm->adler is a crc32 instead of an adler32.
 557 
 558      The memLevel parameter specifies how much memory should be allocated
 559    for the internal compression state.  memLevel=1 uses minimum memory but is
 560    slow and reduces compression ratio; memLevel=9 uses maximum memory for
 561    optimal speed.  The default value is 8.  See zconf.h for total memory usage
 562    as a function of windowBits and memLevel.
 563 
 564      The strategy parameter is used to tune the compression algorithm.  Use the
 565    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
 566    filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
 567    string match), or Z_RLE to limit match distances to one (run-length
 568    encoding).  Filtered data consists mostly of small values with a somewhat
 569    random distribution.  In this case, the compression algorithm is tuned to
 570    compress them better.  The effect of Z_FILTERED is to force more Huffman
 571    coding and less string matching; it is somewhat intermediate between
 572    Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY.  Z_RLE is designed to be almost as
 573    fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data.  The
 574    strategy parameter only affects the compression ratio but not the
 575    correctness of the compressed output even if it is not set appropriately.
 576    Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
 577    decoder for special applications.
 578 
 579      deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
 580    memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
 581    method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
 582    incompatible with the version assumed by the caller (ZLIB_VERSION).  msg is
 583    set to null if there is no error message.  deflateInit2 does not perform any
 584    compression: this will be done by deflate().
 585 */
 586 
 587 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
 588                                              const Bytef *dictionary,
 589                                              uInt  dictLength));
 590 /*
 591      Initializes the compression dictionary from the given byte sequence
 592    without producing any compressed output.  When using the zlib format, this
 593    function must be called immediately after deflateInit, deflateInit2 or
 594    deflateReset, and before any call of deflate.  When doing raw deflate, this
 595    function must be called either before any call of deflate, or immediately
 596    after the completion of a deflate block, i.e. after all input has been
 597    consumed and all output has been delivered when using any of the flush
 598    options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH.  The
 599    compressor and decompressor must use exactly the same dictionary (see
 600    inflateSetDictionary).
 601 
 602      The dictionary should consist of strings (byte sequences) that are likely
 603    to be encountered later in the data to be compressed, with the most commonly
 604    used strings preferably put towards the end of the dictionary.  Using a
 605    dictionary is most useful when the data to be compressed is short and can be
 606    predicted with good accuracy; the data can then be compressed better than
 607    with the default empty dictionary.
 608 
 609      Depending on the size of the compression data structures selected by
 610    deflateInit or deflateInit2, a part of the dictionary may in effect be
 611    discarded, for example if the dictionary is larger than the window size
 612    provided in deflateInit or deflateInit2.  Thus the strings most likely to be
 613    useful should be put at the end of the dictionary, not at the front.  In
 614    addition, the current implementation of deflate will use at most the window
 615    size minus 262 bytes of the provided dictionary.
 616 
 617      Upon return of this function, strm->adler is set to the adler32 value
 618    of the dictionary; the decompressor may later use this value to determine
 619    which dictionary has been used by the compressor.  (The adler32 value
 620    applies to the whole dictionary even if only a subset of the dictionary is
 621    actually used by the compressor.) If a raw deflate was requested, then the
 622    adler32 value is not computed and strm->adler is not set.
 623 
 624      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
 625    parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
 626    inconsistent (for example if deflate has already been called for this stream
 627    or if not at a block boundary for raw deflate).  deflateSetDictionary does
 628    not perform any compression: this will be done by deflate().
 629 */
 630 
 631 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
 632                                     z_streamp source));
 633 /*
 634      Sets the destination stream as a complete copy of the source stream.
 635 
 636      This function can be useful when several compression strategies will be
 637    tried, for example when there are several ways of pre-processing the input
 638    data with a filter.  The streams that will be discarded should then be freed
 639    by calling deflateEnd.  Note that deflateCopy duplicates the internal
 640    compression state which can be quite large, so this strategy is slow and can
 641    consume lots of memory.
 642 
 643      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
 644    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
 645    (such as zalloc being Z_NULL).  msg is left unchanged in both source and
 646    destination.
 647 */
 648 
 649 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
 650 /*
 651      This function is equivalent to deflateEnd followed by deflateInit,
 652    but does not free and reallocate all the internal compression state.  The
 653    stream will keep the same compression level and any other attributes that
 654    may have been set by deflateInit2.
 655 
 656      deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
 657    stream state was inconsistent (such as zalloc or state being Z_NULL).
 658 */
 659 
 660 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
 661                                       int level,
 662                                       int strategy));
 663 /*
 664      Dynamically update the compression level and compression strategy.  The
 665    interpretation of level and strategy is as in deflateInit2.  This can be
 666    used to switch between compression and straight copy of the input data, or
 667    to switch to a different kind of input data requiring a different strategy.
 668    If the compression level is changed, the input available so far is
 669    compressed with the old level (and may be flushed); the new level will take
 670    effect only at the next call of deflate().
 671 
 672      Before the call of deflateParams, the stream state must be set as for
 673    a call of deflate(), since the currently available input may have to be
 674    compressed and flushed.  In particular, strm->avail_out must be non-zero.
 675 
 676      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
 677    stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
 678    strm->avail_out was zero.
 679 */
 680 
 681 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
 682                                     int good_length,
 683                                     int max_lazy,
 684                                     int nice_length,
 685                                     int max_chain));
 686 /*
 687      Fine tune deflate's internal compression parameters.  This should only be
 688    used by someone who understands the algorithm used by zlib's deflate for
 689    searching for the best matching string, and even then only by the most
 690    fanatic optimizer trying to squeeze out the last compressed bit for their
 691    specific input data.  Read the deflate.c source code for the meaning of the
 692    max_lazy, good_length, nice_length, and max_chain parameters.
 693 
 694      deflateTune() can be called after deflateInit() or deflateInit2(), and
 695    returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
 696  */
 697 
 698 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
 699                                        uLong sourceLen));
 700 /*
 701      deflateBound() returns an upper bound on the compressed size after
 702    deflation of sourceLen bytes.  It must be called after deflateInit() or
 703    deflateInit2(), and after deflateSetHeader(), if used.  This would be used
 704    to allocate an output buffer for deflation in a single pass, and so would be
 705    called before deflate().  If that first deflate() call is provided the
 706    sourceLen input bytes, an output buffer allocated to the size returned by
 707    deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
 708    to return Z_STREAM_END.  Note that it is possible for the compressed size to
 709    be larger than the value returned by deflateBound() if flush options other
 710    than Z_FINISH or Z_NO_FLUSH are used.
 711 */
 712 
 713 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
 714                                        unsigned *pending,
 715                                        int *bits));
 716 /*
 717      deflatePending() returns the number of bytes and bits of output that have
 718    been generated, but not yet provided in the available output.  The bytes not
 719    provided would be due to the available output space having being consumed.
 720    The number of bits of output not provided are between 0 and 7, where they
 721    await more bits to join them in order to fill out a full byte.  If pending
 722    or bits are Z_NULL, then those values are not set.
 723 
 724      deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
 725    stream state was inconsistent.
 726  */
 727 
 728 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
 729                                      int bits,
 730                                      int value));
 731 /*
 732      deflatePrime() inserts bits in the deflate output stream.  The intent
 733    is that this function is used to start off the deflate output with the bits
 734    leftover from a previous deflate stream when appending to it.  As such, this
 735    function can only be used for raw deflate, and must be used before the first
 736    deflate() call after a deflateInit2() or deflateReset().  bits must be less
 737    than or equal to 16, and that many of the least significant bits of value
 738    will be inserted in the output.
 739 
 740      deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
 741    room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
 742    source stream state was inconsistent.
 743 */
 744 
 745 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
 746                                          gz_headerp head));
 747 /*
 748      deflateSetHeader() provides gzip header information for when a gzip
 749    stream is requested by deflateInit2().  deflateSetHeader() may be called
 750    after deflateInit2() or deflateReset() and before the first call of
 751    deflate().  The text, time, os, extra field, name, and comment information
 752    in the provided gz_header structure are written to the gzip header (xflag is
 753    ignored -- the extra flags are set according to the compression level).  The
 754    caller must assure that, if not Z_NULL, name and comment are terminated with
 755    a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
 756    available there.  If hcrc is true, a gzip header crc is included.  Note that
 757    the current versions of the command-line version of gzip (up through version
 758    1.3.x) do not support header crc's, and will report that it is a "multi-part
 759    gzip file" and give up.
 760 
 761      If deflateSetHeader is not used, the default gzip header has text false,
 762    the time set to zero, and os set to 255, with no extra, name, or comment
 763    fields.  The gzip header is returned to the default state by deflateReset().
 764 
 765      deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
 766    stream state was inconsistent.
 767 */
 768 
 769 /*
 770 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
 771                                      int  windowBits));
 772 
 773      This is another version of inflateInit with an extra parameter.  The
 774    fields next_in, avail_in, zalloc, zfree and opaque must be initialized
 775    before by the caller.
 776 
 777      The windowBits parameter is the base two logarithm of the maximum window
 778    size (the size of the history buffer).  It should be in the range 8..15 for
 779    this version of the library.  The default value is 15 if inflateInit is used
 780    instead.  windowBits must be greater than or equal to the windowBits value
 781    provided to deflateInit2() while compressing, or it must be equal to 15 if
 782    deflateInit2() was not used.  If a compressed stream with a larger window
 783    size is given as input, inflate() will return with the error code
 784    Z_DATA_ERROR instead of trying to allocate a larger window.
 785 
 786      windowBits can also be zero to request that inflate use the window size in
 787    the zlib header of the compressed stream.
 788 
 789      windowBits can also be -8..-15 for raw inflate.  In this case, -windowBits
 790    determines the window size.  inflate() will then process raw deflate data,
 791    not looking for a zlib or gzip header, not generating a check value, and not
 792    looking for any check values for comparison at the end of the stream.  This
 793    is for use with other formats that use the deflate compressed data format
 794    such as zip.  Those formats provide their own check values.  If a custom
 795    format is developed using the raw deflate format for compressed data, it is
 796    recommended that a check value such as an adler32 or a crc32 be applied to
 797    the uncompressed data as is done in the zlib, gzip, and zip formats.  For
 798    most applications, the zlib format should be used as is.  Note that comments
 799    above on the use in deflateInit2() applies to the magnitude of windowBits.
 800 
 801      windowBits can also be greater than 15 for optional gzip decoding.  Add
 802    32 to windowBits to enable zlib and gzip decoding with automatic header
 803    detection, or add 16 to decode only the gzip format (the zlib format will
 804    return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is a
 805    crc32 instead of an adler32.
 806 
 807      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
 808    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
 809    version assumed by the caller, or Z_STREAM_ERROR if the parameters are
 810    invalid, such as a null pointer to the structure.  msg is set to null if
 811    there is no error message.  inflateInit2 does not perform any decompression
 812    apart from possibly reading the zlib header if present: actual decompression
 813    will be done by inflate().  (So next_in and avail_in may be modified, but
 814    next_out and avail_out are unused and unchanged.) The current implementation
 815    of inflateInit2() does not process any header information -- that is
 816    deferred until inflate() is called.
 817 */
 818 
 819 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
 820                                              const Bytef *dictionary,
 821                                              uInt  dictLength));
 822 /*
 823      Initializes the decompression dictionary from the given uncompressed byte
 824    sequence.  This function must be called immediately after a call of inflate,
 825    if that call returned Z_NEED_DICT.  The dictionary chosen by the compressor
 826    can be determined from the adler32 value returned by that call of inflate.
 827    The compressor and decompressor must use exactly the same dictionary (see
 828    deflateSetDictionary).  For raw inflate, this function can be called at any
 829    time to set the dictionary.  If the provided dictionary is smaller than the
 830    window and there is already data in the window, then the provided dictionary
 831    will amend what's there.  The application must insure that the dictionary
 832    that was used for compression is provided.
 833 
 834      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
 835    parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
 836    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
 837    expected one (incorrect adler32 value).  inflateSetDictionary does not
 838    perform any decompression: this will be done by subsequent calls of
 839    inflate().
 840 */
 841 
 842 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
 843                                              Bytef *dictionary,
 844                                              uInt  *dictLength));
 845 /*
 846      Returns the sliding dictionary being maintained by inflate.  dictLength is
 847    set to the number of bytes in the dictionary, and that many bytes are copied
 848    to dictionary.  dictionary must have enough space, where 32768 bytes is
 849    always enough.  If inflateGetDictionary() is called with dictionary equal to
 850    Z_NULL, then only the dictionary length is returned, and nothing is copied.
 851    Similary, if dictLength is Z_NULL, then it is not set.
 852 
 853      inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
 854    stream state is inconsistent.
 855 */
 856 
 857 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
 858 /*
 859      Skips invalid compressed data until a possible full flush point (see above
 860    for the description of deflate with Z_FULL_FLUSH) can be found, or until all
 861    available input is skipped.  No output is provided.
 862 
 863      inflateSync searches for a 00 00 FF FF pattern in the compressed data.
 864    All full flush points have this pattern, but not all occurrences of this
 865    pattern are full flush points.
 866 
 867      inflateSync returns Z_OK if a possible full flush point has been found,
 868    Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
 869    has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
 870    In the success case, the application may save the current current value of
 871    total_in which indicates where valid compressed data was found.  In the
 872    error case, the application may repeatedly call inflateSync, providing more
 873    input each time, until success or end of the input data.
 874 */
 875 
 876 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
 877                                     z_streamp source));
 878 /*
 879      Sets the destination stream as a complete copy of the source stream.
 880 
 881      This function can be useful when randomly accessing a large stream.  The
 882    first pass through the stream can periodically record the inflate state,
 883    allowing restarting inflate at those points when randomly accessing the
 884    stream.
 885 
 886      inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
 887    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
 888    (such as zalloc being Z_NULL).  msg is left unchanged in both source and
 889    destination.
 890 */
 891 
 892 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
 893 /*
 894      This function is equivalent to inflateEnd followed by inflateInit,
 895    but does not free and reallocate all the internal decompression state.  The
 896    stream will keep attributes that may have been set by inflateInit2.
 897 
 898      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
 899    stream state was inconsistent (such as zalloc or state being Z_NULL).
 900 */
 901 
 902 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
 903                                       int windowBits));
 904 /*
 905      This function is the same as inflateReset, but it also permits changing
 906    the wrap and window size requests.  The windowBits parameter is interpreted
 907    the same as it is for inflateInit2.
 908 
 909      inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
 910    stream state was inconsistent (such as zalloc or state being Z_NULL), or if
 911    the windowBits parameter is invalid.
 912 */
 913 
 914 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
 915                                      int bits,
 916                                      int value));
 917 /*
 918      This function inserts bits in the inflate input stream.  The intent is
 919    that this function is used to start inflating at a bit position in the
 920    middle of a byte.  The provided bits will be used before any bytes are used
 921    from next_in.  This function should only be used with raw inflate, and
 922    should be used before the first inflate() call after inflateInit2() or
 923    inflateReset().  bits must be less than or equal to 16, and that many of the
 924    least significant bits of value will be inserted in the input.
 925 
 926      If bits is negative, then the input stream bit buffer is emptied.  Then
 927    inflatePrime() can be called again to put bits in the buffer.  This is used
 928    to clear out bits leftover after feeding inflate a block description prior
 929    to feeding inflate codes.
 930 
 931      inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
 932    stream state was inconsistent.
 933 */
 934 
 935 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
 936 /*
 937      This function returns two values, one in the lower 16 bits of the return
 938    value, and the other in the remaining upper bits, obtained by shifting the
 939    return value down 16 bits.  If the upper value is -1 and the lower value is
 940    zero, then inflate() is currently decoding information outside of a block.
 941    If the upper value is -1 and the lower value is non-zero, then inflate is in
 942    the middle of a stored block, with the lower value equaling the number of
 943    bytes from the input remaining to copy.  If the upper value is not -1, then
 944    it is the number of bits back from the current bit position in the input of
 945    the code (literal or length/distance pair) currently being processed.  In
 946    that case the lower value is the number of bytes already emitted for that
 947    code.
 948 
 949      A code is being processed if inflate is waiting for more input to complete
 950    decoding of the code, or if it has completed decoding but is waiting for
 951    more output space to write the literal or match data.
 952 
 953      inflateMark() is used to mark locations in the input data for random
 954    access, which may be at bit positions, and to note those cases where the
 955    output of a code may span boundaries of random access blocks.  The current
 956    location in the input stream can be determined from avail_in and data_type
 957    as noted in the description for the Z_BLOCK flush parameter for inflate.
 958 
 959      inflateMark returns the value noted above or -1 << 16 if the provided
 960    source stream state was inconsistent.
 961 */
 962 
 963 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
 964                                          gz_headerp head));
 965 /*
 966      inflateGetHeader() requests that gzip header information be stored in the
 967    provided gz_header structure.  inflateGetHeader() may be called after
 968    inflateInit2() or inflateReset(), and before the first call of inflate().
 969    As inflate() processes the gzip stream, head->done is zero until the header
 970    is completed, at which time head->done is set to one.  If a zlib stream is
 971    being decoded, then head->done is set to -1 to indicate that there will be
 972    no gzip header information forthcoming.  Note that Z_BLOCK or Z_TREES can be
 973    used to force inflate() to return immediately after header processing is
 974    complete and before any actual data is decompressed.
 975 
 976      The text, time, xflags, and os fields are filled in with the gzip header
 977    contents.  hcrc is set to true if there is a header CRC.  (The header CRC
 978    was valid if done is set to one.) If extra is not Z_NULL, then extra_max
 979    contains the maximum number of bytes to write to extra.  Once done is true,
 980    extra_len contains the actual extra field length, and extra contains the
 981    extra field, or that field truncated if extra_max is less than extra_len.
 982    If name is not Z_NULL, then up to name_max characters are written there,
 983    terminated with a zero unless the length is greater than name_max.  If
 984    comment is not Z_NULL, then up to comm_max characters are written there,
 985    terminated with a zero unless the length is greater than comm_max.  When any
 986    of extra, name, or comment are not Z_NULL and the respective field is not
 987    present in the header, then that field is set to Z_NULL to signal its
 988    absence.  This allows the use of deflateSetHeader() with the returned
 989    structure to duplicate the header.  However if those fields are set to
 990    allocated memory, then the application will need to save those pointers
 991    elsewhere so that they can be eventually freed.
 992 
 993      If inflateGetHeader is not used, then the header information is simply
 994    discarded.  The header is always checked for validity, including the header
 995    CRC if present.  inflateReset() will reset the process to discard the header
 996    information.  The application would need to call inflateGetHeader() again to
 997    retrieve the header from the next gzip stream.
 998 
 999      inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1000    stream state was inconsistent.
1001 */
1002 
1003 /*
1004 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1005                                         unsigned char FAR *window));
1006 
1007      Initialize the internal stream state for decompression using inflateBack()
1008    calls.  The fields zalloc, zfree and opaque in strm must be initialized
1009    before the call.  If zalloc and zfree are Z_NULL, then the default library-
1010    derived memory allocation routines are used.  windowBits is the base two
1011    logarithm of the window size, in the range 8..15.  window is a caller
1012    supplied buffer of that size.  Except for special applications where it is
1013    assured that deflate was used with small window sizes, windowBits must be 15
1014    and a 32K byte window must be supplied to be able to decompress general
1015    deflate streams.
1016 
1017      See inflateBack() for the usage of these routines.
1018 
1019      inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1020    the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1021    allocated, or Z_VERSION_ERROR if the version of the library does not match
1022    the version of the header file.
1023 */
1024 
1025 typedef unsigned (*in_func) OF((void FAR *,
1026                                 z_const unsigned char FAR * FAR *));
1027 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1028 
1029 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1030                                     in_func in, void FAR *in_desc,
1031                                     out_func out, void FAR *out_desc));
1032 /*
1033      inflateBack() does a raw inflate with a single call using a call-back
1034    interface for input and output.  This is potentially more efficient than
1035    inflate() for file i/o applications, in that it avoids copying between the
1036    output and the sliding window by simply making the window itself the output
1037    buffer.  inflate() can be faster on modern CPUs when used with large
1038    buffers.  inflateBack() trusts the application to not change the output
1039    buffer passed by the output function, at least until inflateBack() returns.
1040 
1041      inflateBackInit() must be called first to allocate the internal state
1042    and to initialize the state with the user-provided window buffer.
1043    inflateBack() may then be used multiple times to inflate a complete, raw
1044    deflate stream with each call.  inflateBackEnd() is then called to free the
1045    allocated state.
1046 
1047      A raw deflate stream is one with no zlib or gzip header or trailer.
1048    This routine would normally be used in a utility that reads zip or gzip
1049    files and writes out uncompressed files.  The utility would decode the
1050    header and process the trailer on its own, hence this routine expects only
1051    the raw deflate stream to decompress.  This is different from the normal
1052    behavior of inflate(), which expects either a zlib or gzip header and
1053    trailer around the deflate stream.
1054 
1055      inflateBack() uses two subroutines supplied by the caller that are then
1056    called by inflateBack() for input and output.  inflateBack() calls those
1057    routines until it reads a complete deflate stream and writes out all of the
1058    uncompressed data, or until it encounters an error.  The function's
1059    parameters and return types are defined above in the in_func and out_func
1060    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
1061    number of bytes of provided input, and a pointer to that input in buf.  If
1062    there is no input available, in() must return zero--buf is ignored in that
1063    case--and inflateBack() will return a buffer error.  inflateBack() will call
1064    out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
1065    should return zero on success, or non-zero on failure.  If out() returns
1066    non-zero, inflateBack() will return with an error.  Neither in() nor out()
1067    are permitted to change the contents of the window provided to
1068    inflateBackInit(), which is also the buffer that out() uses to write from.
1069    The length written by out() will be at most the window size.  Any non-zero
1070    amount of input may be provided by in().
1071 
1072      For convenience, inflateBack() can be provided input on the first call by
1073    setting strm->next_in and strm->avail_in.  If that input is exhausted, then
1074    in() will be called.  Therefore strm->next_in must be initialized before
1075    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
1076    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
1077    must also be initialized, and then if strm->avail_in is not zero, input will
1078    initially be taken from strm->next_in[0 ..  strm->avail_in - 1].
1079 
1080      The in_desc and out_desc parameters of inflateBack() is passed as the
1081    first parameter of in() and out() respectively when they are called.  These
1082    descriptors can be optionally used to pass any information that the caller-
1083    supplied in() and out() functions need to do their job.
1084 
1085      On return, inflateBack() will set strm->next_in and strm->avail_in to
1086    pass back any unused input that was provided by the last in() call.  The
1087    return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1088    if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1089    in the deflate stream (in which case strm->msg is set to indicate the nature
1090    of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1091    In the case of Z_BUF_ERROR, an input or output error can be distinguished
1092    using strm->next_in which will be Z_NULL only if in() returned an error.  If
1093    strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1094    non-zero.  (in() will always be called before out(), so strm->next_in is
1095    assured to be defined if out() returns non-zero.) Note that inflateBack()
1096    cannot return Z_OK.
1097 */
1098 
1099 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1100 /*
1101      All memory allocated by inflateBackInit() is freed.
1102 
1103      inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1104    state was inconsistent.
1105 */
1106 
1107 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1108 /* Return flags indicating compile-time options.
1109 
1110     Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1111      1.0: size of uInt
1112      3.2: size of uLong
1113      5.4: size of voidpf (pointer)
1114      7.6: size of z_off_t
1115 
1116     Compiler, assembler, and debug options:
1117      8: DEBUG
1118      9: ASMV or ASMINF -- use ASM code
1119      10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1120      11: 0 (reserved)
1121 
1122     One-time table building (smaller code, but not thread-safe if true):
1123      12: BUILDFIXED -- build static block decoding tables when needed
1124      13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1125      14,15: 0 (reserved)
1126 
1127     Library content (indicates missing functionality):
1128      16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1129                           deflate code when not needed)
1130      17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1131                     and decode gzip streams (to avoid linking crc code)
1132      18-19: 0 (reserved)
1133 
1134     Operation variations (changes in library functionality):
1135      20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1136      21: FASTEST -- deflate algorithm with only one, lowest compression level
1137      22,23: 0 (reserved)
1138 
1139     The sprintf variant used by gzprintf (zero is best):
1140      24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1141      25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1142      26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1143 
1144     Remainder:
1145      27-31: 0 (reserved)
1146  */
1147 
1148 #ifndef Z_SOLO
1149 
1150                         /* utility functions */
1151 
1152 /*
1153      The following utility functions are implemented on top of the basic
1154    stream-oriented functions.  To simplify the interface, some default options
1155    are assumed (compression level and memory usage, standard memory allocation
1156    functions).  The source code of these utility functions can be modified if
1157    you need special options.
1158 */
1159 
1160 ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
1161                                  const Bytef *source, uLong sourceLen));
1162 /*
1163      Compresses the source buffer into the destination buffer.  sourceLen is
1164    the byte length of the source buffer.  Upon entry, destLen is the total size
1165    of the destination buffer, which must be at least the value returned by
1166    compressBound(sourceLen).  Upon exit, destLen is the actual size of the
1167    compressed buffer.
1168 
1169      compress returns Z_OK if success, Z_MEM_ERROR if there was not
1170    enough memory, Z_BUF_ERROR if there was not enough room in the output
1171    buffer.
1172 */
1173 
1174 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
1175                                   const Bytef *source, uLong sourceLen,
1176                                   int level));
1177 /*
1178      Compresses the source buffer into the destination buffer.  The level
1179    parameter has the same meaning as in deflateInit.  sourceLen is the byte
1180    length of the source buffer.  Upon entry, destLen is the total size of the
1181    destination buffer, which must be at least the value returned by
1182    compressBound(sourceLen).  Upon exit, destLen is the actual size of the
1183    compressed buffer.
1184 
1185      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1186    memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1187    Z_STREAM_ERROR if the level parameter is invalid.
1188 */
1189 
1190 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1191 /*
1192      compressBound() returns an upper bound on the compressed size after
1193    compress() or compress2() on sourceLen bytes.  It would be used before a
1194    compress() or compress2() call to allocate the destination buffer.
1195 */
1196 
1197 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
1198                                    const Bytef *source, uLong sourceLen));
1199 /*
1200      Decompresses the source buffer into the destination buffer.  sourceLen is
1201    the byte length of the source buffer.  Upon entry, destLen is the total size
1202    of the destination buffer, which must be large enough to hold the entire
1203    uncompressed data.  (The size of the uncompressed data must have been saved
1204    previously by the compressor and transmitted to the decompressor by some
1205    mechanism outside the scope of this compression library.) Upon exit, destLen
1206    is the actual size of the uncompressed buffer.
1207 
1208      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1209    enough memory, Z_BUF_ERROR if there was not enough room in the output
1210    buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.  In
1211    the case where there is not enough room, uncompress() will fill the output
1212    buffer with the uncompressed data up to that point.
1213 */
1214 
1215                         /* gzip file access functions */
1216 
1217 /*
1218      This library supports reading and writing files in gzip (.gz) format with
1219    an interface similar to that of stdio, using the functions that start with
1220    "gz".  The gzip format is different from the zlib format.  gzip is a gzip
1221    wrapper, documented in RFC 1952, wrapped around a deflate stream.
1222 */
1223 
1224 typedef struct gzFile_s *gzFile;    /* semi-opaque gzip file descriptor */
1225 
1226 /*
1227 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1228 
1229      Opens a gzip (.gz) file for reading or writing.  The mode parameter is as
1230    in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1231    a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1232    compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1233    for fixed code compression as in "wb9F".  (See the description of
1234    deflateInit2 for more information about the strategy parameter.)  'T' will
1235    request transparent writing or appending with no compression and not using
1236    the gzip format.
1237 
1238      "a" can be used instead of "w" to request that the gzip stream that will
1239    be written be appended to the file.  "+" will result in an error, since
1240    reading and writing to the same gzip file is not supported.  The addition of
1241    "x" when writing will create the file exclusively, which fails if the file
1242    already exists.  On systems that support it, the addition of "e" when
1243    reading or writing will set the flag to close the file on an execve() call.
1244 
1245      These functions, as well as gzip, will read and decode a sequence of gzip
1246    streams in a file.  The append function of gzopen() can be used to create
1247    such a file.  (Also see gzflush() for another way to do this.)  When
1248    appending, gzopen does not test whether the file begins with a gzip stream,
1249    nor does it look for the end of the gzip streams to begin appending.  gzopen
1250    will simply append a gzip stream to the existing file.
1251 
1252      gzopen can be used to read a file which is not in gzip format; in this
1253    case gzread will directly read from the file without decompression.  When
1254    reading, this will be detected automatically by looking for the magic two-
1255    byte gzip header.
1256 
1257      gzopen returns NULL if the file could not be opened, if there was
1258    insufficient memory to allocate the gzFile state, or if an invalid mode was
1259    specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1260    errno can be checked to determine if the reason gzopen failed was that the
1261    file could not be opened.
1262 */
1263 
1264 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1265 /*
1266      gzdopen associates a gzFile with the file descriptor fd.  File descriptors
1267    are obtained from calls like open, dup, creat, pipe or fileno (if the file
1268    has been previously opened with fopen).  The mode parameter is as in gzopen.
1269 
1270      The next call of gzclose on the returned gzFile will also close the file
1271    descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1272    fd.  If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1273    mode);.  The duplicated descriptor should be saved to avoid a leak, since
1274    gzdopen does not close fd if it fails.  If you are using fileno() to get the
1275    file descriptor from a FILE *, then you will have to use dup() to avoid
1276    double-close()ing the file descriptor.  Both gzclose() and fclose() will
1277    close the associated file descriptor, so they need to have different file
1278    descriptors.
1279 
1280      gzdopen returns NULL if there was insufficient memory to allocate the
1281    gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1282    provided, or '+' was provided), or if fd is -1.  The file descriptor is not
1283    used until the next gz* read, write, seek, or close operation, so gzdopen
1284    will not detect if fd is invalid (unless fd is -1).
1285 */
1286 
1287 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1288 /*
1289      Set the internal buffer size used by this library's functions.  The
1290    default buffer size is 8192 bytes.  This function must be called after
1291    gzopen() or gzdopen(), and before any other calls that read or write the
1292    file.  The buffer memory allocation is always deferred to the first read or
1293    write.  Two buffers are allocated, either both of the specified size when
1294    writing, or one of the specified size and the other twice that size when
1295    reading.  A larger buffer size of, for example, 64K or 128K bytes will
1296    noticeably increase the speed of decompression (reading).
1297 
1298      The new buffer size also affects the maximum length for gzprintf().
1299 
1300      gzbuffer() returns 0 on success, or -1 on failure, such as being called
1301    too late.
1302 */
1303 
1304 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1305 /*
1306      Dynamically update the compression level or strategy.  See the description
1307    of deflateInit2 for the meaning of these parameters.
1308 
1309      gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
1310    opened for writing.
1311 */
1312 
1313 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1314 /*
1315      Reads the given number of uncompressed bytes from the compressed file.  If
1316    the input file is not in gzip format, gzread copies the given number of
1317    bytes into the buffer directly from the file.
1318 
1319      After reaching the end of a gzip stream in the input, gzread will continue
1320    to read, looking for another gzip stream.  Any number of gzip streams may be
1321    concatenated in the input file, and will all be decompressed by gzread().
1322    If something other than a gzip stream is encountered after a gzip stream,
1323    that remaining trailing garbage is ignored (and no error is returned).
1324 
1325      gzread can be used to read a gzip file that is being concurrently written.
1326    Upon reaching the end of the input, gzread will return with the available
1327    data.  If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1328    gzclearerr can be used to clear the end of file indicator in order to permit
1329    gzread to be tried again.  Z_OK indicates that a gzip stream was completed
1330    on the last gzread.  Z_BUF_ERROR indicates that the input file ended in the
1331    middle of a gzip stream.  Note that gzread does not return -1 in the event
1332    of an incomplete gzip stream.  This error is deferred until gzclose(), which
1333    will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1334    stream.  Alternatively, gzerror can be used before gzclose to detect this
1335    case.
1336 
1337      gzread returns the number of uncompressed bytes actually read, less than
1338    len for end of file, or -1 for error.
1339 */
1340 
1341 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1342                                 voidpc buf, unsigned len));
1343 /*
1344      Writes the given number of uncompressed bytes into the compressed file.
1345    gzwrite returns the number of uncompressed bytes written or 0 in case of
1346    error.
1347 */
1348 
1349 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1350 /*
1351      Converts, formats, and writes the arguments to the compressed file under
1352    control of the format string, as in fprintf.  gzprintf returns the number of
1353    uncompressed bytes actually written, or 0 in case of error.  The number of
1354    uncompressed bytes written is limited to 8191, or one less than the buffer
1355    size given to gzbuffer().  The caller should assure that this limit is not
1356    exceeded.  If it is exceeded, then gzprintf() will return an error (0) with
1357    nothing written.  In this case, there may also be a buffer overflow with
1358    unpredictable consequences, which is possible only if zlib was compiled with
1359    the insecure functions sprintf() or vsprintf() because the secure snprintf()
1360    or vsnprintf() functions were not available.  This can be determined using
1361    zlibCompileFlags().
1362 */
1363 
1364 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1365 /*
1366      Writes the given null-terminated string to the compressed file, excluding
1367    the terminating null character.
1368 
1369      gzputs returns the number of characters written, or -1 in case of error.
1370 */
1371 
1372 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1373 /*
1374      Reads bytes from the compressed file until len-1 characters are read, or a
1375    newline character is read and transferred to buf, or an end-of-file
1376    condition is encountered.  If any characters are read or if len == 1, the
1377    string is terminated with a null character.  If no characters are read due
1378    to an end-of-file or len < 1, then the buffer is left untouched.
1379 
1380      gzgets returns buf which is a null-terminated string, or it returns NULL
1381    for end-of-file or in case of error.  If there was an error, the contents at
1382    buf are indeterminate.
1383 */
1384 
1385 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1386 /*
1387      Writes c, converted to an unsigned char, into the compressed file.  gzputc
1388    returns the value that was written, or -1 in case of error.
1389 */
1390 
1391 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1392 /*
1393      Reads one byte from the compressed file.  gzgetc returns this byte or -1
1394    in case of end of file or error.  This is implemented as a macro for speed.
1395    As such, it does not do all of the checking the other functions do.  I.e.
1396    it does not check to see if file is NULL, nor whether the structure file
1397    points to has been clobbered or not.
1398 */
1399 
1400 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1401 /*
1402      Push one character back onto the stream to be read as the first character
1403    on the next read.  At least one character of push-back is allowed.
1404    gzungetc() returns the character pushed, or -1 on failure.  gzungetc() will
1405    fail if c is -1, and may fail if a character has been pushed but not read
1406    yet.  If gzungetc is used immediately after gzopen or gzdopen, at least the
1407    output buffer size of pushed characters is allowed.  (See gzbuffer above.)
1408    The pushed character will be discarded if the stream is repositioned with
1409    gzseek() or gzrewind().
1410 */
1411 
1412 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1413 /*
1414      Flushes all pending output into the compressed file.  The parameter flush
1415    is as in the deflate() function.  The return value is the zlib error number
1416    (see function gzerror below).  gzflush is only permitted when writing.
1417 
1418      If the flush parameter is Z_FINISH, the remaining data is written and the
1419    gzip stream is completed in the output.  If gzwrite() is called again, a new
1420    gzip stream will be started in the output.  gzread() is able to read such
1421    concatented gzip streams.
1422 
1423      gzflush should be called only when strictly necessary because it will
1424    degrade compression if called too often.
1425 */
1426 
1427 /*
1428 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1429                                    z_off_t offset, int whence));
1430 
1431      Sets the starting position for the next gzread or gzwrite on the given
1432    compressed file.  The offset represents a number of bytes in the
1433    uncompressed data stream.  The whence parameter is defined as in lseek(2);
1434    the value SEEK_END is not supported.
1435 
1436      If the file is opened for reading, this function is emulated but can be
1437    extremely slow.  If the file is opened for writing, only forward seeks are
1438    supported; gzseek then compresses a sequence of zeroes up to the new
1439    starting position.
1440 
1441      gzseek returns the resulting offset location as measured in bytes from
1442    the beginning of the uncompressed stream, or -1 in case of error, in
1443    particular if the file is opened for writing and the new starting position
1444    would be before the current position.
1445 */
1446 
1447 ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
1448 /*
1449      Rewinds the given file. This function is supported only for reading.
1450 
1451      gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1452 */
1453 
1454 /*
1455 ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
1456 
1457      Returns the starting position for the next gzread or gzwrite on the given
1458    compressed file.  This position represents a number of bytes in the
1459    uncompressed data stream, and is zero when starting, even if appending or
1460    reading a gzip stream from the middle of a file using gzdopen().
1461 
1462      gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1463 */
1464 
1465 /*
1466 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1467 
1468      Returns the current offset in the file being read or written.  This offset
1469    includes the count of bytes that precede the gzip stream, for example when
1470    appending or when using gzdopen() for reading.  When reading, the offset
1471    does not include as yet unused buffered input.  This information can be used
1472    for a progress indicator.  On error, gzoffset() returns -1.
1473 */
1474 
1475 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1476 /*
1477      Returns true (1) if the end-of-file indicator has been set while reading,
1478    false (0) otherwise.  Note that the end-of-file indicator is set only if the
1479    read tried to go past the end of the input, but came up short.  Therefore,
1480    just like feof(), gzeof() may return false even if there is no more data to
1481    read, in the event that the last read request was for the exact number of
1482    bytes remaining in the input file.  This will happen if the input file size
1483    is an exact multiple of the buffer size.
1484 
1485      If gzeof() returns true, then the read functions will return no more data,
1486    unless the end-of-file indicator is reset by gzclearerr() and the input file
1487    has grown since the previous end of file was detected.
1488 */
1489 
1490 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1491 /*
1492      Returns true (1) if file is being copied directly while reading, or false
1493    (0) if file is a gzip stream being decompressed.
1494 
1495      If the input file is empty, gzdirect() will return true, since the input
1496    does not contain a gzip stream.
1497 
1498      If gzdirect() is used immediately after gzopen() or gzdopen() it will
1499    cause buffers to be allocated to allow reading the file to determine if it
1500    is a gzip file.  Therefore if gzbuffer() is used, it should be called before
1501    gzdirect().
1502 
1503      When writing, gzdirect() returns true (1) if transparent writing was
1504    requested ("wT" for the gzopen() mode), or false (0) otherwise.  (Note:
1505    gzdirect() is not needed when writing.  Transparent writing must be
1506    explicitly requested, so the application already knows the answer.  When
1507    linking statically, using gzdirect() will include all of the zlib code for
1508    gzip file reading and decompression, which may not be desired.)
1509 */
1510 
1511 ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
1512 /*
1513      Flushes all pending output if necessary, closes the compressed file and
1514    deallocates the (de)compression state.  Note that once file is closed, you
1515    cannot call gzerror with file, since its structures have been deallocated.
1516    gzclose must not be called more than once on the same file, just as free
1517    must not be called more than once on the same allocation.
1518 
1519      gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1520    file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1521    last read ended in the middle of a gzip stream, or Z_OK on success.
1522 */
1523 
1524 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1525 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1526 /*
1527      Same as gzclose(), but gzclose_r() is only for use when reading, and
1528    gzclose_w() is only for use when writing or appending.  The advantage to
1529    using these instead of gzclose() is that they avoid linking in zlib
1530    compression or decompression code that is not used when only reading or only
1531    writing respectively.  If gzclose() is used, then both compression and
1532    decompression code will be included the application when linking to a static
1533    zlib library.
1534 */
1535 
1536 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1537 /*
1538      Returns the error message for the last error which occurred on the given
1539    compressed file.  errnum is set to zlib error number.  If an error occurred
1540    in the file system and not in the compression library, errnum is set to
1541    Z_ERRNO and the application may consult errno to get the exact error code.
1542 
1543      The application must not modify the returned string.  Future calls to
1544    this function may invalidate the previously returned string.  If file is
1545    closed, then the string previously returned by gzerror will no longer be
1546    available.
1547 
1548      gzerror() should be used to distinguish errors from end-of-file for those
1549    functions above that do not distinguish those cases in their return values.
1550 */
1551 
1552 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1553 /*
1554      Clears the error and end-of-file flags for file.  This is analogous to the
1555    clearerr() function in stdio.  This is useful for continuing to read a gzip
1556    file that is being written concurrently.
1557 */
1558 
1559 #endif /* !Z_SOLO */
1560 
1561                         /* checksum functions */
1562 
1563 /*
1564      These functions are not related to compression but are exported
1565    anyway because they might be useful in applications using the compression
1566    library.
1567 */
1568 
1569 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1570 /*
1571      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1572    return the updated checksum.  If buf is Z_NULL, this function returns the
1573    required initial value for the checksum.
1574 
1575      An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1576    much faster.
1577 
1578    Usage example:
1579 
1580      uLong adler = adler32(0L, Z_NULL, 0);
1581 
1582      while (read_buffer(buffer, length) != EOF) {
1583        adler = adler32(adler, buffer, length);
1584      }
1585      if (adler != original_adler) error();
1586 */
1587 
1588 /*
1589 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1590                                           z_off_t len2));
1591 
1592      Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
1593    and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1594    each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
1595    seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.  Note
1596    that the z_off_t type (like off_t) is a signed integer.  If len2 is
1597    negative, the result has no meaning or utility.
1598 */
1599 
1600 ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
1601 /*
1602      Update a running CRC-32 with the bytes buf[0..len-1] and return the
1603    updated CRC-32.  If buf is Z_NULL, this function returns the required
1604    initial value for the crc.  Pre- and post-conditioning (one's complement) is
1605    performed within this function so it shouldn't be done by the application.
1606 
1607    Usage example:
1608 
1609      uLong crc = crc32(0L, Z_NULL, 0);
1610 
1611      while (read_buffer(buffer, length) != EOF) {
1612        crc = crc32(crc, buffer, length);
1613      }
1614      if (crc != original_crc) error();
1615 */
1616 
1617 /*
1618 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1619 
1620      Combine two CRC-32 check values into one.  For two sequences of bytes,
1621    seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1622    calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
1623    check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1624    len2.
1625 */
1626 
1627 
1628                         /* various hacks, don't look :) */
1629 
1630 /* deflateInit and inflateInit are macros to allow checking the zlib version
1631  * and the compiler's view of z_stream:
1632  */
1633 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1634                                      const char *version, int stream_size));
1635 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1636                                      const char *version, int stream_size));
1637 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
1638                                       int windowBits, int memLevel,
1639                                       int strategy, const char *version,
1640                                       int stream_size));
1641 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
1642                                       const char *version, int stream_size));
1643 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1644                                          unsigned char FAR *window,
1645                                          const char *version,
1646                                          int stream_size));
1647 #define deflateInit(strm, level) \
1648         deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1649 #define inflateInit(strm) \
1650         inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1651 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1652         deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1653                       (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1654 #define inflateInit2(strm, windowBits) \
1655         inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1656                       (int)sizeof(z_stream))
1657 #define inflateBackInit(strm, windowBits, window) \
1658         inflateBackInit_((strm), (windowBits), (window), \
1659                       ZLIB_VERSION, (int)sizeof(z_stream))
1660 
1661 #ifndef Z_SOLO
1662 
1663 /* gzgetc() macro and its supporting function and exposed data structure.  Note
1664  * that the real internal state is much larger than the exposed structure.
1665  * This abbreviated structure exposes just enough for the gzgetc() macro.  The
1666  * user should not mess with these exposed elements, since their names or
1667  * behavior could change in the future, perhaps even capriciously.  They can
1668  * only be used by the gzgetc() macro.  You have been warned.
1669  */
1670 struct gzFile_s {
1671     unsigned have;
1672     unsigned char *next;
1673     z_off64_t pos;
1674 };
1675 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
1676 #ifdef Z_PREFIX_SET
1677 #  undef z_gzgetc
1678 #  define z_gzgetc(g) \
1679           ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1680 #else
1681 #  define gzgetc(g) \
1682           ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
1683 #endif
1684 
1685 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
1686  * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
1687  * both are true, the application gets the *64 functions, and the regular
1688  * functions are changed to 64 bits) -- in case these are set on systems
1689  * without large file support, _LFS64_LARGEFILE must also be true
1690  */
1691 #ifdef Z_LARGE64
1692    ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1693    ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
1694    ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
1695    ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
1696    ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
1697    ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
1698 #endif
1699 
1700 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1701 #  ifdef Z_PREFIX_SET
1702 #    define z_gzopen z_gzopen64
1703 #    define z_gzseek z_gzseek64
1704 #    define z_gztell z_gztell64
1705 #    define z_gzoffset z_gzoffset64
1706 #    define z_adler32_combine z_adler32_combine64
1707 #    define z_crc32_combine z_crc32_combine64
1708 #  else
1709 #    define gzopen gzopen64
1710 #    define gzseek gzseek64
1711 #    define gztell gztell64
1712 #    define gzoffset gzoffset64
1713 #    define adler32_combine adler32_combine64
1714 #    define crc32_combine crc32_combine64
1715 #  endif
1716 #  ifndef Z_LARGE64
1717      ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
1718      ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
1719      ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
1720      ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
1721      ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
1722      ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1723 #  endif
1724 #else
1725    ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1726    ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1727    ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1728    ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1729    ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1730    ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1731 #endif
1732 
1733 #else /* Z_SOLO */
1734 
1735    ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1736    ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1737 
1738 #endif /* !Z_SOLO */
1739 
1740 /* hack for buggy compilers */
1741 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
1742     struct internal_state {int dummy;};
1743 #endif
1744 
1745 /* undocumented functions */
1746 ZEXTERN const char   * ZEXPORT zError           OF((int));
1747 ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp));
1748 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table    OF((void));
1749 ZEXTERN int            ZEXPORT inflateUndermine OF((z_streamp, int));
1750 ZEXTERN int            ZEXPORT inflateResetKeep OF((z_streamp));
1751 ZEXTERN int            ZEXPORT deflateResetKeep OF((z_streamp));
1752 #if defined(_WIN32) && !defined(Z_SOLO)
1753 ZEXTERN gzFile         ZEXPORT gzopen_w OF((const wchar_t *path,
1754                                             const char *mode));
1755 #endif
1756 #if defined(STDC) || defined(Z_HAVE_STDARG_H)
1757 #  ifndef Z_SOLO
1758 ZEXTERN int            ZEXPORTVA gzvprintf Z_ARG((gzFile file,
1759                                                   const char *format,
1760                                                   va_list va));
1761 #  endif
1762 #endif
1763 
1764 #ifdef __cplusplus
1765 }
1766 #endif
1767 
1768 #endif /* ZLIB_H */