1 /* Portions Copyright (c) 2005-2007 Nokia Corporation and/or its subsidiary(-ies).

     2  * All rights reserved.

     3  */

     4 

     5 /** 

     6 @file

     7 @publishedAll

     8 @externallyDefinedApi

     9 */

    10 

    11 /* zlib.h -- interface of the 'zlib' general purpose compression library

    12   version 1.2.3, July 18th, 2005

    13 

    14   Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler

    15 

    16   This software is provided 'as-is', without any express or implied

    17   warranty.  In no event will the authors be held liable for any damages

    18   arising from the use of this software.

    19 

    20   Permission is granted to anyone to use this software for any purpose,

    21   including commercial applications, and to alter it and redistribute it

    22   freely, subject to the following restrictions:

    23 

    24   1. The origin of this software must not be misrepresented; you must not

    25      claim that you wrote the original software. If you use this software

    26      in a product, an acknowledgment in the product documentation would be

    27      appreciated but is not required.

    28   2. Altered source versions must be plainly marked as such, and must not be

    29      misrepresented as being the original software.

    30   3. This notice may not be removed or altered from any source distribution.

    31 

    32   Jean-loup Gailly        Mark Adler

    33   jloup@gzip.org          madler@alumni.caltech.edu

    34 

    35 

    36   The data format used by the zlib library is described by RFCs (Request for

    37   Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt

    38   (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).

    39 */

    40 

    41 

    42 #ifndef _ZLIB_H

    43 #define _ZLIB_H

    44 

    45 #if (defined(__TOOLS2__) || defined(__TOOLS__))

    46 	// A tools build picks up the zconf.h file from the user include path

    47 	#include "zconf.h"

    48 #else

    49 	// Any other build picks up zconf.h from stdapis system include directory

    50 	#include <zconf.h> 

    51 #endif

    52 

    53 #ifdef __cplusplus

    54 	extern "C" {

    55 #endif

    56 

    57 /** Zlib version */

    58 #define ZLIB_VERSION "1.2.3"

    59 /** Zlib version Number */

    60 #define ZLIB_VERNUM 0x1230

    61 

    62 /**

    63      The 'zlib' compression library provides in-memory compression and

    64   decompression functions, including integrity checks of the uncompressed

    65   data.  This version of the library supports only one compression method

    66   (deflation) but other algorithms will be added later and will have the same

    67   stream interface.

    68 

    69      Compression can be done in a single step if the buffers are large

    70   enough (for example if an input file is mmap'ed), or can be done by

    71   repeated calls of the compression function.  In the latter case, the

    72   application must provide more input and/or consume the output

    73   (providing more output space) before each call.

    74 

    75      The compressed data format used by default by the in-memory functions is

    76   the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped

    77   around a deflate stream, which is itself documented in RFC 1951.

    78 

    79      The library also supports reading and writing files in gzip (.gz) format

    80   with an interface similar to that of stdio using the functions that start

    81   with "gz".  The gzip format is different from the zlib format.  gzip is a

    82   gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.

    83 

    84      This library can optionally read and write gzip streams in memory as well.

    85 

    86      The zlib format was designed to be compact and fast for use in memory

    87   and on communications channels.  The gzip format was designed for single-

    88   file compression on file systems, has a larger header than zlib to maintain

    89   directory information, and uses a different, slower check method than zlib.

    90 

    91      The library does not install any signal handler. The decoder checks

    92   the consistency of the compressed data, so the library should never

    93   crash even in case of corrupted input.

    94 */

    95 

    96 /** Function pointer - used to allocate the internal state */

    97 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));

    98 /** Function pointer - used to free the internal state */

    99 typedef void   (*free_func)  OF((voidpf opaque, voidpf address));

   100 

   101 struct internal_state;

   102 

   103 /**

   104 	Encapsulates a zip stream

   105 */

   106 typedef struct z_stream_s {

   107 	/** Next input byte */

   108     Bytef    *next_in;  

   109     /** Number of bytes available at next_in */

   110     uInt     avail_in;  

   111     /** Total nb of input bytes read so far */

   112     uLong    total_in;  

   113 

   114     /** Next output byte should be put there */

   115     Bytef    *next_out; 

   116     /** Remaining free space at next_out */

   117     uInt     avail_out; 

   118     /** Total nb of bytes output so far */

   119     uLong    total_out; 

   120 

   121     /** Last error message, NULL if no error */

   122     char     *msg;      

   123     /** Not visible by applications */

   124     struct internal_state FAR *state; 

   125 

   126     /** Used to allocate the internal state */

   127     alloc_func zalloc;  

   128     /** Used to free the internal state */

   129     free_func  zfree;   

   130     /** Private data object passed to zalloc and zfree */

   131     voidpf     opaque;  

   132 

   133     /** Best guess about the data type: binary or text */

   134     int     data_type;  

   135     /** Adler32 value of the uncompressed data */

   136     uLong   adler;      

   137     /** Reserved for future use */

   138     uLong   reserved;   

   139 } z_stream;

   140 

   141 /** typedef z_stream* as z_streamp. Refer to z_stream_s for more details */

   142 typedef z_stream FAR *z_streamp;

   143 

   144 /**

   145      gzip header information passed to and from zlib routines.  See RFC 1952

   146   for more details on the meanings of these fields.

   147 */

   148 typedef struct gz_header_s {

   149 	/** True if compressed data believed to be text */

   150     int     text;       

   151     /** Modification time */

   152     uLong   time;       

   153     /** Extra flags (not used when writing a gzip file) */

   154     int     xflags;     

   155     /** Operating system */

   156     int     os;         

   157     /** Pointer to extra field or Z_NULL if none */

   158     Bytef   *extra;     

   159     /** Extra field length (valid if extra != Z_NULL) */

   160     uInt    extra_len;  

   161     /** Space at extra (only when reading header) */

   162     uInt    extra_max;  

   163     /** Pointer to zero-terminated file name or Z_NULL */

   164     Bytef   *name;      

   165     /** Space at name (only when reading header) */

   166     uInt    name_max;   

   167     /** Pointer to zero-terminated comment or Z_NULL */

   168     Bytef   *comment;   

   169     /** Space at comment (only when reading header) */

   170     uInt    comm_max;   

   171     /** True if there was or will be a header crc */

   172     int     hcrc;       

   173     /** True when done reading gzip header (not used when writing a gzip file) */

   174     int     done;   

   175 } gz_header;

   176 

   177 /** gz_headerp is typedef gz_header* */

   178 typedef gz_header FAR *gz_headerp;

   179 

   180 /*

   181    The application must update next_in and avail_in when avail_in has

   182    dropped to zero. It must update next_out and avail_out when avail_out

   183    has dropped to zero. The application must initialize zalloc, zfree and

   184    opaque before calling the init function. All other fields are set by the

   185    compression library and must not be updated by the application.

   186 

   187    The opaque value provided by the application will be passed as the first

   188    parameter for calls of zalloc and zfree. This can be useful for custom

   189    memory management. The compression library attaches no meaning to the

   190    opaque value.

   191 

   192    zalloc must return Z_NULL if there is not enough memory for the object.

   193    If zlib is used in a multi-threaded application, zalloc and zfree must be

   194    thread safe.

   195 

   196    On 16-bit systems, the functions zalloc and zfree must be able to allocate

   197    exactly 65536 bytes, but will not be required to allocate more than this

   198    if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,

   199    pointers returned by zalloc for objects of exactly 65536 bytes *must*

   200    have their offset normalized to zero. The default allocation function

   201    provided by this library ensures this (see zutil.c). To reduce memory

   202    requirements and avoid any allocation of 64K objects, at the expense of

   203    compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).

   204 

   205    The fields total_in and total_out can be used for statistics or

   206    progress reports. After compression, total_in holds the total size of

   207    the uncompressed data and may be saved for use in the decompressor

   208    (particularly if the decompressor wants to decompress everything in

   209    a single step).

   210 */

   211 

   212                         /* constants */

   213 

   214 /** Allowed flush values; see deflate() and inflate() below for details */

   215 #define Z_NO_FLUSH      0

   216 /** Allowed flush values; see deflate() and inflate() below for details. This constant will be removed, use Z_SYNC_FLUSH instead*/

   217 #define Z_PARTIAL_FLUSH 1

   218 /** Allowed flush values; see deflate() and inflate() below for details */

   219 #define Z_SYNC_FLUSH    2

   220 /** Allowed flush values; see deflate() and inflate() below for details */

   221 #define Z_FULL_FLUSH    3

   222 /** Allowed flush values; see deflate() and inflate() below for details */

   223 #define Z_FINISH        4

   224 /** Allowed flush values; see deflate() and inflate() below for details */

   225 #define Z_BLOCK         5

   226 

   227 

   228 /** Return codes for the compression/decompression functions. Negative

   229 values are errors, positive values are used for special but normal events. */

   230 #define Z_OK            0

   231 /** Return codes for the compression/decompression functions. Negative

   232 values are errors, positive values are used for special but normal events. */

   233 #define Z_STREAM_END    1

   234 /** Return codes for the compression/decompression functions. Negative

   235 values are errors, positive values are used for special but normal events. */

   236 #define Z_NEED_DICT     2

   237 /** Return codes for the compression/decompression functions. Negative

   238 values are errors, positive values are used for special but normal events. */

   239 #define Z_ERRNO        (-1)

   240 /** Return codes for the compression/decompression functions. Negative

   241 values are errors, positive values are used for special but normal events. */

   242 #define Z_STREAM_ERROR (-2)

   243 /** Return codes for the compression/decompression functions. Negative

   244 values are errors, positive values are used for special but normal events. */

   245 #define Z_DATA_ERROR   (-3)

   246 /** Return codes for the compression/decompression functions. Negative

   247 values are errors, positive values are used for special but normal events. */

   248 #define Z_MEM_ERROR    (-4)

   249 /** Return codes for the compression/decompression functions. Negative

   250 values are errors, positive values are used for special but normal events. */

   251 #define Z_BUF_ERROR    (-5)

   252 /** Return codes for the compression/decompression functions. Negative

   253 values are errors, positive values are used for special but normal events. */

   254 #define Z_VERSION_ERROR (-6)

   255 

   256 

   257 /** Compression level as no compression */

   258 #define Z_NO_COMPRESSION         0

   259 /** Compression level for best speed */

   260 #define Z_BEST_SPEED             1

   261 /** Compression level for best compression */

   262 #define Z_BEST_COMPRESSION       9

   263 /** Compression level for default compression */

   264 #define Z_DEFAULT_COMPRESSION  (-1)

   265 

   266 

   267 /** Compression strategy; see deflateInit2() below for details */

   268 #define Z_FILTERED            1

   269 /** Compression strategy; see deflateInit2() below for details */

   270 #define Z_HUFFMAN_ONLY        2

   271 /** Compression strategy; see deflateInit2() below for details */

   272 #define Z_RLE                 3

   273 /** Compression strategy; see deflateInit2() below for details */

   274 #define Z_FIXED               4

   275 /** Compression strategy; see deflateInit2() below for details */

   276 #define Z_DEFAULT_STRATEGY    0

   277 

   278 

   279 /** Possible values of the data_type field (though see inflate()) */

   280 #define Z_BINARY   0

   281 /** Possible values of the data_type field (though see inflate()) */

   282 #define Z_TEXT     1

   283 /** Possible values of the data_type field (though see inflate()). It is used for compatibility with 1.2.2 and earlier */

   284 #define Z_ASCII    Z_TEXT   

   285 /** Possible values of the data_type field (though see inflate()) */

   286 #define Z_UNKNOWN  2

   287 

   288 

   289 /** The deflate compression method (the only one supported in this version) */

   290 #define Z_DEFLATED   8

   291 

   292 /** For initializing zalloc, zfree, opaque */

   293 #define Z_NULL  0  

   294 

   295 /** For compatibility with versions < 1.0.2 */

   296 #define zlib_version zlibVersion()

   297 

   298 

   299                         /* basic functions */

   300 

   301 /** The application can compare zlibVersion and ZLIB_VERSION for consistency.

   302    If the first character differs, the library code actually used is

   303    not compatible with the zlib.h header file used by the application.

   304    This check is automatically made by deflateInit and inflateInit.

   305    @return returns zlib version 

   306  */

   307 ZEXTERN const char * ZEXPORT zlibVersion OF((void));

   308 

   309 /*

   310 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));

   311 

   312      Initializes the internal stream state for compression. The fields

   313    zalloc, zfree and opaque must be initialized before by the caller.

   314    If zalloc and zfree are set to Z_NULL, deflateInit updates them to

   315    use default allocation functions.

   316 

   317      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:

   318    1 gives best speed, 9 gives best compression, 0 gives no compression at

   319    all (the input data is simply copied a block at a time).

   320    Z_DEFAULT_COMPRESSION requests a default compromise between speed and

   321    compression (currently equivalent to level 6).

   322 

   323      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not

   324    enough memory, Z_STREAM_ERROR if level is not a valid compression level,

   325    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible

   326    with the version assumed by the caller (ZLIB_VERSION).

   327    msg is set to null if there is no error message.  deflateInit does not

   328    perform any compression: this will be done by deflate().

   329 */

   330 

   331 /**

   332     deflate compresses as much data as possible, and stops when the input

   333   buffer becomes empty or the output buffer becomes full. It may introduce some

   334   output latency (reading input without producing any output) except when

   335   forced to flush.

   336 

   337     The detailed semantics are as follows. deflate performs one or both of the

   338   following actions:

   339 

   340   - Compress more input starting at next_in and update next_in and avail_in

   341     accordingly. If not all input can be processed (because there is not

   342     enough room in the output buffer), next_in and avail_in are updated and

   343     processing will resume at this point for the next call of deflate().

   344 

   345   - Provide more output starting at next_out and update next_out and avail_out

   346     accordingly. This action is forced if the parameter flush is non zero.

   347     Forcing flush frequently degrades the compression ratio, so this parameter

   348     should be set only when necessary (in interactive applications).

   349     Some output may be provided even if flush is not set.

   350 

   351   Before the call of deflate(), the application should ensure that at least

   352   one of the actions is possible, by providing more input and/or consuming

   353   more output, and updating avail_in or avail_out accordingly; avail_out

   354   should never be zero before the call. The application can consume the

   355   compressed output when it wants, for example when the output buffer is full

   356   (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK

   357   and with zero avail_out, it must be called again after making room in the

   358   output buffer because there might be more output pending.

   359 

   360     Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to

   361   decide how much data to accumualte before producing output, in order to

   362   maximize compression.

   363 

   364     If the parameter flush is set to Z_SYNC_FLUSH, all pending output is

   365   flushed to the output buffer and the output is aligned on a byte boundary, so

   366   that the decompressor can get all input data available so far. (In particular

   367   avail_in is zero after the call if enough output space has been provided

   368   before the call.)  Flushing may degrade compression for some compression

   369   algorithms and so it should be used only when necessary.

   370 

   371     If flush is set to Z_FULL_FLUSH, all output is flushed as with

   372   Z_SYNC_FLUSH, and the compression state is reset so that decompression can

   373   restart from this point if previous compressed data has been damaged or if

   374   random access is desired. Using Z_FULL_FLUSH too often can seriously degrade

   375   compression.

   376 

   377     If deflate returns with avail_out == 0, this function must be called again

   378   with the same value of the flush parameter and more output space (updated

   379   avail_out), until the flush is complete (deflate returns with non-zero

   380   avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that

   381   avail_out is greater than six to avoid repeated flush markers due to

   382   avail_out == 0 on return.

   383 

   384     If the parameter flush is set to Z_FINISH, pending input is processed,

   385   pending output is flushed and deflate returns with Z_STREAM_END if there

   386   was enough output space; if deflate returns with Z_OK, this function must be

   387   called again with Z_FINISH and more output space (updated avail_out) but no

   388   more input data, until it returns with Z_STREAM_END or an error. After

   389   deflate has returned Z_STREAM_END, the only possible operations on the

   390   stream are deflateReset or deflateEnd.

   391 

   392     Z_FINISH can be used immediately after deflateInit if all the compression

   393   is to be done in a single step. In this case, avail_out must be at least

   394   the value returned by deflateBound (see below). If deflate does not return

   395   Z_STREAM_END, then it must be called again as described above.

   396 

   397     deflate() sets strm->adler to the adler32 checksum of all input read

   398   so far (that is, total_in bytes).

   399 

   400     deflate() may update strm->data_type if it can make a good guess about

   401   the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered

   402   binary. This field is only for information purposes and does not affect

   403   the compression algorithm in any manner.

   404 

   405     deflate() returns Z_OK if some progress has been made (more input

   406   processed or more output produced), Z_STREAM_END if all input has been

   407   consumed and all output has been produced (only when flush is set to

   408   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example

   409   if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible

   410   (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not

   411   fatal, and deflate() can be called again with more input and more output

   412   space to continue compressing.

   413   

   414   @param strm Stream of data

   415   @param flush Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to

   416   decide how much data to accumualte before producing output, in order to

   417   maximize compression. Refer to the description above for more details.

   418   @return deflate returns Z_OK on success. Refer to the description above for more details.

   419 */

   420 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));

   421 

   422 /**

   423      All dynamically allocated data structures for this stream are freed.

   424    This function discards any unprocessed input and does not flush any

   425    pending output.

   426 

   427      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the

   428    stream state was inconsistent, Z_DATA_ERROR if the stream was freed

   429    prematurely (some input or output was discarded). In the error case,

   430    msg may be set but then points to a static string (which must not be

   431    deallocated).

   432    

   433    @param strm Stream of data

   434    @return deflateEnd returns Z_OK on success. Refer to the description above for more details.

   435 */

   436 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));

   437 

   438 /*

   439 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));

   440 

   441      Initializes the internal stream state for decompression. The fields

   442    next_in, avail_in, zalloc, zfree and opaque must be initialized before by

   443    the caller. If next_in is not Z_NULL and avail_in is large enough (the exact

   444    value depends on the compression method), inflateInit determines the

   445    compression method from the zlib header and allocates all data structures

   446    accordingly; otherwise the allocation will be deferred to the first call of

   447    inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to

   448    use default allocation functions.

   449 

   450      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough

   451    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the

   452    version assumed by the caller.  msg is set to null if there is no error

   453    message. inflateInit does not perform any decompression apart from reading

   454    the zlib header if present: this will be done by inflate().  (So next_in and

   455    avail_in may be modified, but next_out and avail_out are unchanged.)

   456 */

   457 

   458 /**

   459     inflate decompresses as much data as possible, and stops when the input

   460   buffer becomes empty or the output buffer becomes full. It may introduce

   461   some output latency (reading input without producing any output) except when

   462   forced to flush.

   463 

   464   The detailed semantics are as follows. inflate performs one or both of the

   465   following actions:

   466 

   467   - Decompress more input starting at next_in and update next_in and avail_in

   468     accordingly. If not all input can be processed (because there is not

   469     enough room in the output buffer), next_in is updated and processing

   470     will resume at this point for the next call of inflate().

   471 

   472   - Provide more output starting at next_out and update next_out and avail_out

   473     accordingly.  inflate() provides as much output as possible, until there

   474     is no more input data or no more space in the output buffer (see below

   475     about the flush parameter).

   476 

   477   Before the call of inflate(), the application should ensure that at least

   478   one of the actions is possible, by providing more input and/or consuming

   479   more output, and updating the next_* and avail_* values accordingly.

   480   The application can consume the uncompressed output when it wants, for

   481   example when the output buffer is full (avail_out == 0), or after each

   482   call of inflate(). If inflate returns Z_OK and with zero avail_out, it

   483   must be called again after making room in the output buffer because there

   484   might be more output pending.

   485 

   486     The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,

   487   Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much

   488   output as possible to the output buffer. Z_BLOCK requests that inflate() stop

   489   if and when it gets to the next deflate block boundary. When decoding the

   490   zlib or gzip format, this will cause inflate() to return immediately after

   491   the header and before the first block. When doing a raw inflate, inflate()

   492   will go ahead and process the first block, and will return when it gets to

   493   the end of that block, or when it runs out of data.

   494 

   495     The Z_BLOCK option assists in appending to or combining deflate streams.

   496   Also to assist in this, on return inflate() will set strm->data_type to the

   497   number of unused bits in the last byte taken from strm->next_in, plus 64

   498   if inflate() is currently decoding the last block in the deflate stream,

   499   plus 128 if inflate() returned immediately after decoding an end-of-block

   500   code or decoding the complete header up to just before the first byte of the

   501   deflate stream. The end-of-block will not be indicated until all of the

   502   uncompressed data from that block has been written to strm->next_out.  The

   503   number of unused bits may in general be greater than seven, except when

   504   bit 7 of data_type is set, in which case the number of unused bits will be

   505   less than eight.

   506 

   507     inflate() should normally be called until it returns Z_STREAM_END or an

   508   error. However if all decompression is to be performed in a single step

   509   (a single call of inflate), the parameter flush should be set to

   510   Z_FINISH. In this case all pending input is processed and all pending

   511   output is flushed; avail_out must be large enough to hold all the

   512   uncompressed data. (The size of the uncompressed data may have been saved

   513   by the compressor for this purpose.) The next operation on this stream must

   514   be inflateEnd to deallocate the decompression state. The use of Z_FINISH

   515   is never required, but can be used to inform inflate that a faster approach

   516   may be used for the single inflate() call.

   517 

   518      In this implementation, inflate() always flushes as much output as

   519   possible to the output buffer, and always uses the faster approach on the

   520   first call. So the only effect of the flush parameter in this implementation

   521   is on the return value of inflate(), as noted below, or when it returns early

   522   because Z_BLOCK is used.

   523 

   524      If a preset dictionary is needed after this call (see inflateSetDictionary

   525   below), inflate sets strm->adler to the adler32 checksum of the dictionary

   526   chosen by the compressor and returns Z_NEED_DICT; otherwise it sets

   527   strm->adler to the adler32 checksum of all output produced so far (that is,

   528   total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described

   529   below. At the end of the stream, inflate() checks that its computed adler32

   530   checksum is equal to that saved by the compressor and returns Z_STREAM_END

   531   only if the checksum is correct.

   532 

   533     inflate() will decompress and check either zlib-wrapped or gzip-wrapped

   534   deflate data.  The header type is detected automatically.  Any information

   535   contained in the gzip header is not retained, so applications that need that

   536   information should instead use raw inflate, see inflateInit2() below, or

   537   inflateBack() and perform their own processing of the gzip header and

   538   trailer.

   539 

   540     inflate() returns Z_OK if some progress has been made (more input processed

   541   or more output produced), Z_STREAM_END if the end of the compressed data has

   542   been reached and all uncompressed output has been produced, Z_NEED_DICT if a

   543   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was

   544   corrupted (input stream not conforming to the zlib format or incorrect check

   545   value), Z_STREAM_ERROR if the stream structure was inconsistent (for example

   546   if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,

   547   Z_BUF_ERROR if no progress is possible or if there was not enough room in the

   548   output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and

   549   inflate() can be called again with more input and more output space to

   550   continue decompressing. If Z_DATA_ERROR is returned, the application may then

   551   call inflateSync() to look for a good compression block if a partial recovery

   552   of the data is desired.

   553 

   554   @param strm Stream of data

   555   @param flush This parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,

   556   Z_FINISH, or Z_BLOCK. Refer to the description for more details.

   557   @return inflate returns Z_OK on success. Refer to the description above for more details.

   558 */

   559 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));

   560 

   561 /**

   562      All dynamically allocated data structures for this stream are freed.

   563    This function discards any unprocessed input and does not flush any

   564    pending output.

   565 

   566   @param strm Stream of data

   567   @return inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state

   568    was inconsistent. In the error case, msg may be set but then points to a

   569    static string (which must not be deallocated). 

   570 */

   571 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));

   572 

   573                         /* Advanced functions */

   574 

   575 /*

   576     The following functions are needed only in some special applications.

   577 */

   578 

   579 /*

   580 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,

   581                                      int  level,

   582                                      int  method,

   583                                      int  windowBits,

   584                                      int  memLevel,

   585                                      int  strategy));

   586 

   587      This is another version of deflateInit with more compression options. The

   588    fields next_in, zalloc, zfree and opaque must be initialized before by

   589    the caller.

   590 

   591      The method parameter is the compression method. It must be Z_DEFLATED in

   592    this version of the library.

   593 

   594      The windowBits parameter is the base two logarithm of the window size

   595    (the size of the history buffer). It should be in the range 8..15 for this

   596    version of the library. Larger values of this parameter result in better

   597    compression at the expense of memory usage. The default value is 15 if

   598    deflateInit is used instead.

   599 

   600      Note: In this version of the library a windowBits value of 8 is unsupported

   601    due to a problem with the window size being set to 256 bytes. Although a

   602    value of 8 will be accepted by deflateInit2(), as it is being changed

   603    internally from 8 to 9, it will not be possible to use the same value when it

   604    comes to decompression. This is because inflateInit2() does not make the same

   605    change internally and as a result a Z_DATA_ERROR is returned when calling

   606    inflate(). It is therefore advised that for this version of the library 

   607    windowBits of 9 is used in place of 8.

   608 

   609      windowBits can also be -8..-15 for raw deflate. In this case, -windowBits

   610    determines the window size. deflate() will then generate raw deflate data

   611    with no zlib header or trailer, and will not compute an adler32 check value.

   612 

   613      windowBits can also be greater than 15 for optional gzip encoding. Add

   614    16 to windowBits to write a simple gzip header and trailer around the

   615    compressed data instead of a zlib wrapper. The gzip header will have no

   616    file name, no extra data, no comment, no modification time (set to zero),

   617    no header crc, and the operating system will be set to 3 (UNIX).  If a

   618    gzip stream is being written, strm->adler is a crc32 instead of an adler32.

   619 

   620      The memLevel parameter specifies how much memory should be allocated

   621    for the internal compression state. memLevel=1 uses minimum memory but

   622    is slow and reduces compression ratio; memLevel=9 uses maximum memory

   623    for optimal speed. The default value is 8. See zconf.h for total memory

   624    usage as a function of windowBits and memLevel.

   625 

   626      The strategy parameter is used to tune the compression algorithm. Use the

   627    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a

   628    filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no

   629    string match), or Z_RLE to limit match distances to one (run-length

   630    encoding). Filtered data consists mostly of small values with a somewhat

   631    random distribution. In this case, the compression algorithm is tuned to

   632    compress them better. The effect of Z_FILTERED is to force more Huffman

   633    coding and less string matching; it is somewhat intermediate between

   634    Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as

   635    Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy

   636    parameter only affects the compression ratio but not the correctness of the

   637    compressed output even if it is not set appropriately.  Z_FIXED prevents the

   638    use of dynamic Huffman codes, allowing for a simpler decoder for special

   639    applications.

   640 

   641       deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough

   642    memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid

   643    method). msg is set to null if there is no error message.  deflateInit2 does

   644    not perform any compression: this will be done by deflate().

   645 */

   646 

   647 /**

   648      Initializes the compression dictionary from the given byte sequence

   649    without producing any compressed output. This function must be called

   650    immediately after deflateInit, deflateInit2 or deflateReset, before any

   651    call of deflate. The compressor and decompressor must use exactly the same

   652    dictionary (see inflateSetDictionary).

   653 

   654      The dictionary should consist of strings (byte sequences) that are likely

   655    to be encountered later in the data to be compressed, with the most commonly

   656    used strings preferably put towards the end of the dictionary. Using a

   657    dictionary is most useful when the data to be compressed is short and can be

   658    predicted with good accuracy; the data can then be compressed better than

   659    with the default empty dictionary.

   660 

   661      Depending on the size of the compression data structures selected by

   662    deflateInit or deflateInit2, a part of the dictionary may in effect be

   663    discarded, for example if the dictionary is larger than the window size in

   664    deflate or deflate2. Thus the strings most likely to be useful should be

   665    put at the end of the dictionary, not at the front. In addition, the

   666    current implementation of deflate will use at most the window size minus

   667    262 bytes of the provided dictionary.

   668 

   669      Upon return of this function, strm->adler is set to the adler32 value

   670    of the dictionary; the decompressor may later use this value to determine

   671    which dictionary has been used by the compressor. (The adler32 value

   672    applies to the whole dictionary even if only a subset of the dictionary is

   673    actually used by the compressor.) If a raw deflate was requested, then the

   674    adler32 value is not computed and strm->adler is not set.

   675    

   676   @param strm Stream of data

   677   @param dictionary Pointer to the dictionary. Refer to the description above for more details.

   678   @param dictLength Dictionay Length

   679   @return deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a

   680    parameter is invalid (such as NULL dictionary) or the stream state is

   681    inconsistent (for example if deflate has already been called for this stream

   682    or if the compression method is bsort). deflateSetDictionary does not

   683    perform any compression: this will be done by deflate(). 

   684 */

   685 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,

   686                                              const Bytef *dictionary,

   687                                              uInt  dictLength));

   688 

   689 /**

   690      Sets the destination stream as a complete copy of the source stream.

   691 

   692      This function can be useful when several compression strategies will be

   693    tried, for example when there are several ways of pre-processing the input

   694    data with a filter. The streams that will be discarded should then be freed

   695    by calling deflateEnd.  Note that deflateCopy duplicates the internal

   696    compression state which can be quite large, so this strategy is slow and

   697    can consume lots of memory.

   698    

   699    @param dest destination stream 

   700    @param souce source stream of data

   701    @return deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not

   702    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent

   703    (such as zalloc being NULL). msg is left unchanged in both source and

   704    destination.

   705 */

   706 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,

   707                                     z_streamp source));

   708 

   709 /**

   710      This function is equivalent to deflateEnd followed by deflateInit,

   711    but does not free and reallocate all the internal compression state.

   712    The stream will keep the same compression level and any other attributes

   713    that may have been set by deflateInit2.

   714    

   715    @param strm stream of data

   716    @return deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source

   717    stream state was inconsistent (such as zalloc or state being NULL).

   718 */

   719 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));

   720 

   721 /**

   722      Dynamically update the compression level and compression strategy.  The

   723    interpretation of level and strategy is as in deflateInit2.  This can be

   724    used to switch between compression and straight copy of the input data, or

   725    to switch to a different kind of input data requiring a different

   726    strategy. If the compression level is changed, the input available so far

   727    is compressed with the old level (and may be flushed); the new level will

   728    take effect only at the next call of deflate().

   729 

   730      Before the call of deflateParams, the stream state must be set as for

   731    a call of deflate(), since the currently available input may have to

   732    be compressed and flushed. In particular, strm->avail_out must be non-zero.

   733    

   734    @param strm stream of data

   735    @param level compression level

   736    @param strategy compression algorithm

   737    @return deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source

   738    stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR

   739    if strm->avail_out was zero.

   740 */

   741 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,

   742                                       int level,

   743                                       int strategy));

   744 

   745 /**

   746      Fine tune deflate's internal compression parameters.  This should only be

   747    used by someone who understands the algorithm used by zlib's deflate for

   748    searching for the best matching string, and even then only by the most

   749    fanatic optimizer trying to squeeze out the last compressed bit for their

   750    specific input data.  Read the deflate.c source code for the meaning of the

   751    max_lazy, good_length, nice_length, and max_chain parameters.

   752 

   753      deflateTune() can be called after deflateInit() or deflateInit2()

   754    

   755    @param strm stream of data

   756    @param good_length reduce lazy search above this match length

   757    @param max_lazy do not perform lazy search above this match length

   758    @param nice_length quit search above this match length

   759    @param max_chain

   760    @return deflateTune returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.

   761  */

   762 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,

   763                                     int good_length,

   764                                     int max_lazy,

   765                                     int nice_length,

   766                                     int max_chain));

   767 

   768 /**

   769      deflateBound() returns an upper bound on the compressed size after

   770    deflation of sourceLen bytes.  It must be called after deflateInit()

   771    or deflateInit2().  This would be used to allocate an output buffer

   772    for deflation in a single pass, and so would be called before deflate().

   773    

   774    @param strm stream of data

   775    @param sourceLen source length

   776    @return deflateBound returns an upper bound on the compressed size after

   777    deflation of sourceLen bytes.

   778 */

   779 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,

   780                                        uLong sourceLen));

   781 

   782 /**

   783      deflatePrime() inserts bits in the deflate output stream.  The intent

   784   is that this function is used to start off the deflate output with the

   785   bits leftover from a previous deflate stream when appending to it.  As such,

   786   this function can only be used for raw deflate, and must be used before the

   787   first deflate() call after a deflateInit2() or deflateReset().  bits must be

   788   less than or equal to 16, and that many of the least significant bits of

   789   value will be inserted in the output.

   790    

   791    @param strm stream of data

   792    @param bits bits must be less than or equal to 16, and that many of the least 

   793    significant bits of value will be inserted in the output.

   794    @param value represents value of the bits to be inserted

   795    @return deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source

   796    stream state was inconsistent.

   797 */

   798 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,

   799                                      int bits,

   800                                      int value));

   801 

   802 /**

   803       deflateSetHeader() provides gzip header information for when a gzip

   804    stream is requested by deflateInit2().  deflateSetHeader() may be called

   805    after deflateInit2() or deflateReset() and before the first call of

   806    deflate().  The text, time, os, extra field, name, and comment information

   807    in the provided gz_header structure are written to the gzip header (xflag is

   808    ignored -- the extra flags are set according to the compression level).  The

   809    caller must assure that, if not Z_NULL, name and comment are terminated with

   810    a zero byte, and that if extra is not Z_NULL, that extra_len bytes are

   811    available there.  If hcrc is true, a gzip header crc is included.  Note that

   812    the current versions of the command-line version of gzip (up through version

   813    1.3.x) do not support header crc's, and will report that it is a "multi-part

   814    gzip file" and give up.

   815 

   816       If deflateSetHeader is not used, the default gzip header has text false,

   817    the time set to zero, and os set to 3, with no extra, name, or comment

   818    fields.  The gzip header is returned to the default state by deflateReset().

   819    

   820    @param strm stream of data

   821    @param head gzip header

   822    @return deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source

   823    stream state was inconsistent.

   824 */

   825 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,

   826                                          gz_headerp head));

   827 

   828 /*

   829 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,

   830                                      int  windowBits));

   831 

   832      This is another version of inflateInit with an extra parameter. The

   833    fields next_in, avail_in, zalloc, zfree and opaque must be initialized

   834    before by the caller.

   835 

   836      The windowBits parameter is the base two logarithm of the maximum window

   837    size (the size of the history buffer).  It should be in the range 8..15 for

   838    this version of the library. The default value is 15 if inflateInit is used

   839    instead. windowBits must be greater than or equal to the windowBits value

   840    provided to deflateInit2() while compressing, or it must be equal to 15 if

   841    deflateInit2() was not used. If a compressed stream with a larger window

   842    size is given as input, inflate() will return with the error code

   843    Z_DATA_ERROR instead of trying to allocate a larger window.

   844 

   845      Note: In this version of the library a windowBits value of 8 is unsupported

   846    due to a problem with the window size being set to 256 bytes. Although a

   847    value of 8 will be accepted by deflateInit2(), as it is being changed

   848    internally from 8 to 9, it will not be possible to use the same value when it

   849    comes to decompression. This is because inflateInit2() does not make the same

   850    change internally and as a result a Z_DATA_ERROR is returned when calling

   851    inflate(). It is therefore advised that for this version of the library 

   852    windowBits of 9 is used in place of 8.

   853 

   854      windowBits can also be -8..-15 for raw inflate. In this case, -windowBits

   855    determines the window size. inflate() will then process raw deflate data,

   856    not looking for a zlib or gzip header, not generating a check value, and not

   857    looking for any check values for comparison at the end of the stream. This

   858    is for use with other formats that use the deflate compressed data format

   859    such as zip.  Those formats provide their own check values. If a custom

   860    format is developed using the raw deflate format for compressed data, it is

   861    recommended that a check value such as an adler32 or a crc32 be applied to

   862    the uncompressed data as is done in the zlib, gzip, and zip formats.  For

   863    most applications, the zlib format should be used as is. Note that comments

   864    above on the use in deflateInit2() applies to the magnitude of windowBits.

   865 

   866      windowBits can also be greater than 15 for optional gzip decoding. Add

   867    32 to windowBits to enable zlib and gzip decoding with automatic header

   868    detection, or add 16 to decode only the gzip format (the zlib format will

   869    return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is

   870    a crc32 instead of an adler32.

   871 

   872      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough

   873    memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg

   874    is set to null if there is no error message.  inflateInit2 does not perform

   875    any decompression apart from reading the zlib header if present: this will

   876    be done by inflate(). (So next_in and avail_in may be modified, but next_out

   877    and avail_out are unchanged.)

   878 */

   879 

   880 /**

   881      Initializes the decompression dictionary from the given uncompressed byte

   882    sequence. This function must be called immediately after a call of inflate,

   883    if that call returned Z_NEED_DICT. The dictionary chosen by the compressor

   884    can be determined from the adler32 value returned by that call of inflate.

   885    The compressor and decompressor must use exactly the same dictionary (see

   886    deflateSetDictionary).  For raw inflate, this function can be called

   887    immediately after inflateInit2() or inflateReset() and before any call of

   888    inflate() to set the dictionary.  The application must insure that the

   889    dictionary that was used for compression is provided.

   890 

   891    inflateSetDictionary does not perform any decompression: this will be done 

   892    by subsequent calls of inflate().

   893    

   894    @param strm stream of data

   895    @param dictionary Pointer to dictionary

   896    @param dictLength Dictionary Length

   897    @return inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a

   898    parameter is invalid (such as NULL dictionary) or the stream state is

   899    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the

   900    expected one (incorrect adler32 value). 

   901 */

   902 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,

   903                                              const Bytef *dictionary,

   904                                              uInt  dictLength));

   905 

   906 /**

   907     Skips invalid compressed data until a full flush point (see above the

   908   description of deflate with Z_FULL_FLUSH) can be found, or until all

   909   available input is skipped. No output is provided.

   910 

   911   @param strm Stream of data

   912   @return inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR

   913   if no more input was provided, Z_DATA_ERROR if no flush point has been found,

   914   or Z_STREAM_ERROR if the stream structure was inconsistent. In the success

   915   case, the application may save the current current value of total_in which

   916   indicates where valid compressed data was found. In the error case, the

   917   application may repeatedly call inflateSync, providing more input each time,

   918   until success or end of the input data.

   919 */

   920 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));

   921 

   922 /**

   923      Sets the destination stream as a complete copy of the source stream.

   924 

   925      This function can be useful when randomly accessing a large stream.  The

   926    first pass through the stream can periodically record the inflate state,

   927    allowing restarting inflate at those points when randomly accessing the

   928    stream.

   929    

   930    @param dest destination stream

   931    @param source source stream of data

   932    @return inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not

   933    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent

   934    (such as zalloc being NULL). msg is left unchanged in both source and

   935    destination.

   936 */

   937 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,

   938                                     z_streamp source));

   939 

   940 /**

   941      This function is equivalent to inflateEnd followed by inflateInit,

   942    but does not free and reallocate all the internal decompression state.

   943    The stream will keep attributes that may have been set by inflateInit2.

   944 

   945    @param strm Stream of data

   946    @return inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source

   947    stream state was inconsistent (such as zalloc or state being NULL).

   948 */

   949 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));

   950 

   951 /**

   952      This function inserts bits in the inflate input stream.  The intent is

   953   that this function is used to start inflating at a bit position in the

   954   middle of a byte.  The provided bits will be used before any bytes are used

   955   from next_in.  This function should only be used with raw inflate, and

   956   should be used before the first inflate() call after inflateInit2() or

   957   inflateReset().  bits must be less than or equal to 16, and that many of the

   958   least significant bits of value will be inserted in the input.

   959 

   960    @param strm stream of data

   961    @param bits bits must be less than or equal to 16, and that many of the

   962    least significant bits of value will be inserted in the input.

   963    @param value @param value represents value of the bits to be inserted

   964    @return inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source

   965    stream state was inconsistent.

   966 */

   967 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,

   968                                      int bits,

   969                                      int value));

   970 

   971 /**

   972       inflateGetHeader() requests that gzip header information be stored in the

   973    provided gz_header structure.  inflateGetHeader() may be called after

   974    inflateInit2() or inflateReset(), and before the first call of inflate().

   975    As inflate() processes the gzip stream, head->done is zero until the header

   976    is completed, at which time head->done is set to one.  If a zlib stream is

   977    being decoded, then head->done is set to -1 to indicate that there will be

   978    no gzip header information forthcoming.  Note that Z_BLOCK can be used to

   979    force inflate() to return immediately after header processing is complete

   980    and before any actual data is decompressed.

   981 

   982       The text, time, xflags, and os fields are filled in with the gzip header

   983    contents.  hcrc is set to true if there is a header CRC.  (The header CRC

   984    was valid if done is set to one.)  If extra is not Z_NULL, then extra_max

   985    contains the maximum number of bytes to write to extra.  Once done is true,

   986    extra_len contains the actual extra field length, and extra contains the

   987    extra field, or that field truncated if extra_max is less than extra_len.

   988    If name is not Z_NULL, then up to name_max characters are written there,

   989    terminated with a zero unless the length is greater than name_max.  If

   990    comment is not Z_NULL, then up to comm_max characters are written there,

   991    terminated with a zero unless the length is greater than comm_max.  When

   992    any of extra, name, or comment are not Z_NULL and the respective field is

   993    not present in the header, then that field is set to Z_NULL to signal its

   994    absence.  This allows the use of deflateSetHeader() with the returned

   995    structure to duplicate the header.  However if those fields are set to

   996    allocated memory, then the application will need to save those pointers

   997    elsewhere so that they can be eventually freed.

   998 

   999       If inflateGetHeader is not used, then the header information is simply

  1000    discarded.  The header is always checked for validity, including the header

  1001    CRC if present.  inflateReset() will reset the process to discard the header

  1002    information.  The application would need to call inflateGetHeader() again to

  1003    retrieve the header from the next gzip stream.

  1004 

  1005    @param stream of data

  1006    @param head gzip header

  1007    @return inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source

  1008    stream state was inconsistent.

  1009 */

  1010 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,

  1011                                          gz_headerp head));

  1012 

  1013 /*

  1014 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,

  1015                                         unsigned char FAR *window));

  1016 

  1017      Initialize the internal stream state for decompression using inflateBack()

  1018    calls.  The fields zalloc, zfree and opaque in strm must be initialized

  1019    before the call.  If zalloc and zfree are Z_NULL, then the default library-

  1020    derived memory allocation routines are used.  windowBits is the base two

  1021    logarithm of the window size, in the range 8..15.  window is a caller

  1022    supplied buffer of that size.  Except for special applications where it is

  1023    assured that deflate was used with small window sizes, windowBits must be 15

  1024    and a 32K byte window must be supplied to be able to decompress general

  1025    deflate streams.

  1026 

  1027      Note: In this version of the library a windowBits value of 8 is unsupported

  1028    due to a problem with the window size being set to 256 bytes. Although a

  1029    value of 8 will be accepted by deflateInit2(), as it is being changed

  1030    internally from 8 to 9, it will not be possible to use the same value when it

  1031    comes to decompression. This is because inflateInit2() does not make the same

  1032    change internally and as a result a Z_DATA_ERROR is returned when calling

  1033    inflate(). It is therefore advised that for this version of the library 

  1034    windowBits of 9 is used in place of 8.

  1035 

  1036      See inflateBack() for the usage of these routines.

  1037 

  1038      inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of

  1039    the paramaters are invalid, Z_MEM_ERROR if the internal state could not

  1040    be allocated, or Z_VERSION_ERROR if the version of the library does not

  1041    match the version of the header file.

  1042 */

  1043 

  1044 /** Input function pointer defined to be used in inflateBack */

  1045 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));

  1046 /** Output function pointer defined to be used in inflateBack */

  1047 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));

  1048 

  1049 

  1050 /**

  1051      inflateBack() does a raw inflate with a single call using a call-back

  1052    interface for input and output.  This is more efficient than inflate() for

  1053    file i/o applications in that it avoids copying between the output and the

  1054    sliding window by simply making the window itself the output buffer.  This

  1055    function trusts the application to not change the output buffer passed by

  1056    the output function, at least until inflateBack() returns.

  1057 

  1058      inflateBackInit() must be called first to allocate the internal state

  1059    and to initialize the state with the user-provided window buffer.

  1060    inflateBack() may then be used multiple times to inflate a complete, raw

  1061    deflate stream with each call.  inflateBackEnd() is then called to free

  1062    the allocated state.

  1063 

  1064      A raw deflate stream is one with no zlib or gzip header or trailer.

  1065    This routine would normally be used in a utility that reads zip or gzip

  1066    files and writes out uncompressed files.  The utility would decode the

  1067    header and process the trailer on its own, hence this routine expects

  1068    only the raw deflate stream to decompress.  This is different from the

  1069    normal behavior of inflate(), which expects either a zlib or gzip header and

  1070    trailer around the deflate stream.

  1071 

  1072      inflateBack() uses two subroutines supplied by the caller that are then

  1073    called by inflateBack() for input and output.  inflateBack() calls those

  1074    routines until it reads a complete deflate stream and writes out all of the

  1075    uncompressed data, or until it encounters an error.  The function's

  1076    parameters and return types are defined above in the in_func and out_func

  1077    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the

  1078    number of bytes of provided input, and a pointer to that input in buf.  If

  1079    there is no input available, in() must return zero--buf is ignored in that

  1080    case--and inflateBack() will return a buffer error.  inflateBack() will call

  1081    out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()

  1082    should return zero on success, or non-zero on failure.  If out() returns

  1083    non-zero, inflateBack() will return with an error.  Neither in() nor out()

  1084    are permitted to change the contents of the window provided to

  1085    inflateBackInit(), which is also the buffer that out() uses to write from.

  1086    The length written by out() will be at most the window size.  Any non-zero

  1087    amount of input may be provided by in().

  1088 

  1089      For convenience, inflateBack() can be provided input on the first call by

  1090    setting strm->next_in and strm->avail_in.  If that input is exhausted, then

  1091    in() will be called.  Therefore strm->next_in must be initialized before

  1092    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called

  1093    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in

  1094    must also be initialized, and then if strm->avail_in is not zero, input will

  1095    initially be taken from strm->next_in[0 .. strm->avail_in - 1].

  1096 

  1097      The in_desc and out_desc parameters of inflateBack() is passed as the

  1098    first parameter of in() and out() respectively when they are called.  These

  1099    descriptors can be optionally used to pass any information that the caller-

  1100    supplied in() and out() functions need to do their job.

  1101 

  1102      On return, inflateBack() will set strm->next_in and strm->avail_in to

  1103    pass back any unused input that was provided by the last in() call.  The

  1104    return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR

  1105    if in() or out() returned an error, Z_DATA_ERROR if there was a format

  1106    error in the deflate stream (in which case strm->msg is set to indicate the

  1107    nature of the error), or Z_STREAM_ERROR if the stream was not properly

  1108    initialized.  In the case of Z_BUF_ERROR, an input or output error can be

  1109    distinguished using strm->next_in which will be Z_NULL only if in() returned

  1110    an error.  If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to

  1111    out() returning non-zero.  (in() will always be called before out(), so

  1112    strm->next_in is assured to be defined if out() returns non-zero.)  Note

  1113    that inflateBack() cannot return Z_OK.

  1114    

  1115    @param strm stream of data

  1116    @param in input function pointer

  1117    @param in_desc input parameters for in_func

  1118    @param out output function pointer

  1119    @param out_desc output parameters for out_func

  1120    @return Refer to the above description for detailed explanation

  1121 */

  1122 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,

  1123                                     in_func in, void FAR *in_desc,

  1124                                     out_func out, void FAR *out_desc));

  1125 

  1126 /**

  1127      All memory allocated by inflateBackInit() is freed.

  1128 

  1129    @param strm stream of data

  1130    @return inflateBackEnd returns Z_OK on success, or Z_STREAM_ERROR if the stream

  1131    state was inconsistent.

  1132 */

  1133 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));

  1134 

  1135 /**