1 /** 

     2 @file

     3 @publishedAll

     4 @released

     5 */

     6 

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

     8   version 1.2.3, July 18th, 2005

     9 

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

    11 

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

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

    14   arising from the use of this software.

    15 

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

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

    18   freely, subject to the following restrictions:

    19 

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

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

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

    23      appreciated but is not required.

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

    25      misrepresented as being the original software.

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

    27 

    28   Jean-loup Gailly        Mark Adler

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

    30 

    31 

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

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

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

    35 */

    36 

    37 

    38 #ifndef _ZLIB_H

    39 #define _ZLIB_H

    40 

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

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

    43 	#include "zconf.h"

    44 #else

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

    46 	#include <zconf.h> 

    47 #endif

    48 

    49 #ifdef __cplusplus

    50 	extern "C" {

    51 #endif

    52 

    53 /** Zlib version */

    54 #define ZLIB_VERSION "1.2.3"

    55 /** Zlib version Number */

    56 #define ZLIB_VERNUM 0x1230

    57 

    58 /**

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

    60   decompression functions, including integrity checks of the uncompressed

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

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

    63   stream interface.

    64 

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

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

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

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

    69   (providing more output space) before each call.

    70 

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

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

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

    74 

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

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

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

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

    79 

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

    81 

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

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

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

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

    86 

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

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

    89   crash even in case of corrupted input.

    90 */

    91 

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

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

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

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

    96 

    97 struct internal_state;

    98 

    99 /**

   100 	Encapsulates a zip stream

   101 */

   102 typedef struct z_stream_s {

   103 	/** Next input byte */

   104     Bytef    *next_in;  

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

   106     uInt     avail_in;  

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

   108     uLong    total_in;  

   109 

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

   111     Bytef    *next_out; 

   112     /** Remaining free space at next_out */

   113     uInt     avail_out; 

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

   115     uLong    total_out; 

   116 

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

   118     char     *msg;      

   119     /** Not visible by applications */

   120     struct internal_state FAR *state; 

   121 

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

   123     alloc_func zalloc;  

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

   125     free_func  zfree;   

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

   127     voidpf     opaque;  

   128 

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

   130     int     data_type;  

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

   132     uLong   adler;      

   133     /** Reserved for future use */

   134     uLong   reserved;   

   135 } z_stream;

   136 

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

   138 typedef z_stream FAR *z_streamp;

   139 

   140 /**

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

   142   for more details on the meanings of these fields.

   143 */

   144 typedef struct gz_header_s {

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

   146     int     text;       

   147     /** Modification time */

   148     uLong   time;       

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

   150     int     xflags;     

   151     /** Operating system */

   152     int     os;         

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

   154     Bytef   *extra;     

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

   156     uInt    extra_len;  

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

   158     uInt    extra_max;  

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

   160     Bytef   *name;      

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

   162     uInt    name_max;   

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

   164     Bytef   *comment;   

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

   166     uInt    comm_max;   

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

   168     int     hcrc;       

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

   170     int     done;   

   171 } gz_header;

   172 

   173 /** gz_headerp is typedef gz_header* */

   174 typedef gz_header FAR *gz_headerp;

   175 

   176 /*

   177    The application must update next_in and avail_in when avail_in has

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

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

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

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

   182 

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

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

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

   186    opaque value.

   187 

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

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

   190    thread safe.

   191 

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

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

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

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

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

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

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

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

   200 

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

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

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

   204    (particularly if the decompressor wants to decompress everything in

   205    a single step).

   206 */

   207 

   208                         /* constants */

   209 

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

   211 #define Z_NO_FLUSH      0

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

   213 #define Z_PARTIAL_FLUSH 1

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

   215 #define Z_SYNC_FLUSH    2

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

   217 #define Z_FULL_FLUSH    3

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

   219 #define Z_FINISH        4

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

   221 #define Z_BLOCK         5

   222 

   223 

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

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

   226 #define Z_OK            0

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

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

   229 #define Z_STREAM_END    1

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

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

   232 #define Z_NEED_DICT     2

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

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

   235 #define Z_ERRNO        (-1)

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

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

   238 #define Z_STREAM_ERROR (-2)

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

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

   241 #define Z_DATA_ERROR   (-3)

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

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

   244 #define Z_MEM_ERROR    (-4)

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

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

   247 #define Z_BUF_ERROR    (-5)

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

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

   250 #define Z_VERSION_ERROR (-6)

   251 

   252 

   253 /** Compression level as no compression */

   254 #define Z_NO_COMPRESSION         0

   255 /** Compression level for best speed */

   256 #define Z_BEST_SPEED             1

   257 /** Compression level for best compression */

   258 #define Z_BEST_COMPRESSION       9

   259 /** Compression level for default compression */

   260 #define Z_DEFAULT_COMPRESSION  (-1)

   261 

   262 

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

   264 #define Z_FILTERED            1

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

   266 #define Z_HUFFMAN_ONLY        2

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

   268 #define Z_RLE                 3

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

   270 #define Z_FIXED               4

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

   272 #define Z_DEFAULT_STRATEGY    0

   273 

   274 

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

   276 #define Z_BINARY   0

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

   278 #define Z_TEXT     1

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

   280 #define Z_ASCII    Z_TEXT   

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

   282 #define Z_UNKNOWN  2

   283 

   284 

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

   286 #define Z_DEFLATED   8

   287 

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

   289 #define Z_NULL  0  

   290 

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

   292 #define zlib_version zlibVersion()

   293 

   294 

   295                         /* basic functions */

   296 

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

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

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

   300    This check is automatically made by deflateInit and inflateInit.

   301    @return returns zlib version 

   302  */

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

   304 

   305 /*

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

   307 

   308      Initializes the internal stream state for compression. The fields

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

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

   311    use default allocation functions.

   312 

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

   314    1 gives best speed, 9 gives best compression, 0 gives no compression at

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

   316    Z_DEFAULT_COMPRESSION requests a default compromise between speed and

   317    compression (currently equivalent to level 6).

   318 

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

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

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

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

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

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

   325 */

   326 

   327 /**

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

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

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

   331   forced to flush.

   332 

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

   334   following actions:

   335 

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

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

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

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

   340 

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

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

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

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

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

   346 

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

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

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

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

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

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

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

   354   output buffer because there might be more output pending.

   355 

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

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

   358   maximize compression.

   359 

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

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

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

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

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

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

   366 

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

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

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

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

   371   compression.

   372 

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

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

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

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

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

   378   avail_out == 0 on return.

   379 

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

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

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

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

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

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

   386   stream are deflateReset or deflateEnd.

   387 

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

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

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

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

   392 

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

   394   so far (that is, total_in bytes).

   395 

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

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

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

   399   the compression algorithm in any manner.

   400 

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

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

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

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

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

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

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

   408   space to continue compressing.

   409   

   410   @param strm Stream of data

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

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

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

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

   415 */

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

   417 

   418 /**

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

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

   421    pending output.

   422 

   423      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the

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

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

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

   427    deallocated).

   428    

   429    @param strm Stream of data

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

   431 */

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

   433 

   434 /*

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

   436 

   437      Initializes the internal stream state for decompression. The fields

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

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

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

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

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

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

   444    use default allocation functions.

   445 

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

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

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

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

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

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

   452 */

   453 

   454 /**

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

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

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

   458   forced to flush.

   459 

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

   461   following actions:

   462 

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

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

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

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

   467 

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

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

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

   471     about the flush parameter).

   472 

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

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

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

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

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

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

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

   480   might be more output pending.

   481 

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

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

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

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

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

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

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

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

   490 

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

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

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

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

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

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

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

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

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

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

   501   less than eight.

   502 

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

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

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

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

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

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

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

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

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

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

   513 

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

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

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

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

   518   because Z_BLOCK is used.

   519 

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

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

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

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

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

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

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

   527   only if the checksum is correct.

   528 

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

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

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

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

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

   534   trailer.

   535 

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

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

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

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

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

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

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

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

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

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

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

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

   548   of the data is desired.

   549 

   550   @param strm Stream of data

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

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

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

   554 */

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

   556 

   557 /**

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

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

   560    pending output.

   561 

   562   @param strm Stream of data

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

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

   565    static string (which must not be deallocated). 

   566 */

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

   568 

   569                         /* Advanced functions */

   570 

   571 /*

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

   573 */

   574 

   575 /*

   576 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,

   577                                      int  level,

   578                                      int  method,

   579                                      int  windowBits,

   580                                      int  memLevel,

   581                                      int  strategy));

   582 

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

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

   585    the caller.

   586 

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

   588    this version of the library.

   589 

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

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

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

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

   594    deflateInit is used instead.

   595 

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

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

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

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

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

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

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

   603    windowBits of 9 is used in place of 8.

   604 

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

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

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

   608 

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

   610    16 to windowBits to write a simple gzip header and trailer around the

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

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

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

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

   615 

   616      The memLevel parameter specifies how much memory should be allocated

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

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

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

   620    usage as a function of windowBits and memLevel.

   621 

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

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

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

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

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

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

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

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

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

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

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

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

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

   635    applications.

   636 

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

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

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

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

   641 */

   642 

   643 /**

   644      Initializes the compression dictionary from the given byte sequence

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

   646    immediately after deflateInit, deflateInit2 or deflateReset, before any

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

   648    dictionary (see inflateSetDictionary).

   649 

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

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

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

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

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

   655    with the default empty dictionary.

   656 

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

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

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

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

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

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

   663    262 bytes of the provided dictionary.

   664 

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

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

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

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

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

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

   671    

   672   @param strm Stream of data

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

   674   @param dictLength Dictionay Length

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

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

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

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

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

   680 */

   681 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,

   682                                              const Bytef *dictionary,

   683                                              uInt  dictLength));

   684 

   685 /**

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

   687 

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

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

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

   691    by calling deflateEnd.  Note that deflateCopy duplicates the internal

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

   693    can consume lots of memory.

   694    

   695    @param dest destination stream 

   696    @param souce source stream of data

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

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

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

   700    destination.

   701 */

   702 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,

   703                                     z_streamp source));

   704 

   705 /**

   706      This function is equivalent to deflateEnd followed by deflateInit,

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

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

   709    that may have been set by deflateInit2.

   710    

   711    @param strm stream of data

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

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

   714 */

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

   716 

   717 /**

   718      Dynamically update the compression level and compression strategy.  The

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

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

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

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

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

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

   725 

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

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

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

   729    

   730    @param strm stream of data

   731    @param level compression level

   732    @param strategy compression algorithm

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

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

   735    if strm->avail_out was zero.

   736 */

   737 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,

   738                                       int level,

   739                                       int strategy));

   740 

   741 /**

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

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

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

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

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

   747    max_lazy, good_length, nice_length, and max_chain parameters.

   748 

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

   750    

   751    @param strm stream of data

   752    @param good_length reduce lazy search above this match length

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

   754    @param nice_length quit search above this match length

   755    @param max_chain

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

   757  */

   758 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,

   759                                     int good_length,

   760                                     int max_lazy,

   761                                     int nice_length,

   762                                     int max_chain));

   763 

   764 /**

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

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

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

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

   769    

   770    @param strm stream of data

   771    @param sourceLen source length

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

   773    deflation of sourceLen bytes.

   774 */

   775 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,

   776                                        uLong sourceLen));

   777 

   778 /**

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

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

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

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

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

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

   785   value will be inserted in the output.

   786    

   787    @param strm stream of data

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

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

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

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

   792    stream state was inconsistent.

   793 */

   794 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,

   795                                      int bits,

   796                                      int value));

   797 

   798 /**

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

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

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

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

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

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

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

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

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

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

   809    1.3.x) do not support header crc's, and will report that it is a "multi-part

   810    gzip file" and give up.

   811 

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

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

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

   815    

   816    @param strm stream of data

   817    @param head gzip header

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

   819    stream state was inconsistent.

   820 */

   821 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,

   822                                          gz_headerp head));

   823 

   824 /*

   825 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,

   826                                      int  windowBits));

   827 

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

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

   830    before by the caller.

   831 

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

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

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

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

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

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

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

   839    Z_DATA_ERROR instead of trying to allocate a larger window.

   840 

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

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

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

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

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

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

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

   848    windowBits of 9 is used in place of 8.

   849 

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

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

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

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

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

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

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

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

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

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

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

   861 

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

   863    32 to windowBits to enable zlib and gzip decoding with automatic header

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

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

   866    a crc32 instead of an adler32.

   867 

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

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

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

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

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

   873    and avail_out are unchanged.)

   874 */

   875 

   876 /**

   877      Initializes the decompression dictionary from the given uncompressed byte

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

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

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

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

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

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

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

   885    dictionary that was used for compression is provided.

   886 

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

   888    by subsequent calls of inflate().

   889    

   890    @param strm stream of data

   891    @param dictionary Pointer to dictionary

   892    @param dictLength Dictionary Length

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

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

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

   896    expected one (incorrect adler32 value). 

   897 */

   898 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,

   899                                              const Bytef *dictionary,

   900                                              uInt  dictLength));

   901 

   902 /**

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

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

   905   available input is skipped. No output is provided.

   906 

   907   @param strm Stream of data

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

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

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

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

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

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

   914   until success or end of the input data.

   915 */

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

   917 

   918 /**

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

   920 

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

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

   923    allowing restarting inflate at those points when randomly accessing the

   924    stream.

   925    

   926    @param dest destination stream

   927    @param source source stream of data

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

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

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

   931    destination.

   932 */

   933 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,

   934                                     z_streamp source));

   935 

   936 /**

   937      This function is equivalent to inflateEnd followed by inflateInit,

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

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

   940 

   941    @param strm Stream of data

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

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

   944 */

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

   946 

   947 /**

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

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

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

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

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

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

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

   955 

   956    @param strm stream of data

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

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

   961    stream state was inconsistent.

   962 */

   963 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,

   964                                      int bits,

   965                                      int value));

   966 

   967 /**

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

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

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

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

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

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

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

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

   976    and before any actual data is decompressed.

   977 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

   993    elsewhere so that they can be eventually freed.

   994 

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

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

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

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

   999    retrieve the header from the next gzip stream.

  1000 

  1001    @param stream of data

  1002    @param head gzip header

  1003    @return inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source

  1004    stream state was inconsistent.

  1005 */

  1006 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,

  1007                                          gz_headerp head));

  1008 

  1009 /*

  1010 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,

  1011                                         unsigned char FAR *window));

  1012 

  1013      Initialize the internal stream state for decompression using inflateBack()

  1014    calls.  The fields zalloc, zfree and opaque in strm must be initialized

  1015    before the call.  If zalloc and zfree are Z_NULL, then the default library-

  1016    derived memory allocation routines are used.  windowBits is the base two

  1017    logarithm of the window size, in the range 8..15.  window is a caller

  1018    supplied buffer of that size.  Except for special applications where it is

  1019    assured that deflate was used with small window sizes, windowBits must be 15

  1020    and a 32K byte window must be supplied to be able to decompress general

  1021    deflate streams.

  1022 

  1023      Note: In this version of the library a windowBits value of 8 is unsupported

  1024    due to a problem with the window size being set to 256 bytes. Although a

  1025    value of 8 will be accepted by deflateInit2(), as it is being changed

  1026    internally from 8 to 9, it will not be possible to use the same value when it

  1027    comes to decompression. This is because inflateInit2() does not make the same

  1028    change internally and as a result a Z_DATA_ERROR is returned when calling

  1029    inflate(). It is therefore advised that for this version of the library 

  1030    windowBits of 9 is used in place of 8.

  1031 

  1032      See inflateBack() for the usage of these routines.

  1033 

  1034      inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of

  1035    the paramaters are invalid, Z_MEM_ERROR if the internal state could not

  1036    be allocated, or Z_VERSION_ERROR if the version of the library does not

  1037    match the version of the header file.

  1038 */

  1039 

  1040 /** Input function pointer defined to be used in inflateBack */

  1041 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));

  1042 /** Output function pointer defined to be used in inflateBack */

  1043 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));

  1044 

  1045 

  1046 /**

  1047      inflateBack() does a raw inflate with a single call using a call-back

  1048    interface for input and output.  This is more efficient than inflate() for

  1049    file i/o applications in that it avoids copying between the output and the

  1050    sliding window by simply making the window itself the output buffer.  This

  1051    function trusts the application to not change the output buffer passed by

  1052    the output function, at least until inflateBack() returns.

  1053 

  1054      inflateBackInit() must be called first to allocate the internal state

  1055    and to initialize the state with the user-provided window buffer.

  1056    inflateBack() may then be used multiple times to inflate a complete, raw

  1057    deflate stream with each call.  inflateBackEnd() is then called to free

  1058    the allocated state.

  1059 

  1060      A raw deflate stream is one with no zlib or gzip header or trailer.

  1061    This routine would normally be used in a utility that reads zip or gzip

  1062    files and writes out uncompressed files.  The utility would decode the

  1063    header and process the trailer on its own, hence this routine expects

  1064    only the raw deflate stream to decompress.  This is different from the

  1065    normal behavior of inflate(), which expects either a zlib or gzip header and

  1066    trailer around the deflate stream.

  1067 

  1068      inflateBack() uses two subroutines supplied by the caller that are then

  1069    called by inflateBack() for input and output.  inflateBack() calls those

  1070    routines until it reads a complete deflate stream and writes out all of the

  1071    uncompressed data, or until it encounters an error.  The function's

  1072    parameters and return types are defined above in the in_func and out_func

  1073    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the

  1074    number of bytes of provided input, and a pointer to that input in buf.  If

  1075    there is no input available, in() must return zero--buf is ignored in that

  1076    case--and inflateBack() will return a buffer error.  inflateBack() will call

  1077    out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()

  1078    should return zero on success, or non-zero on failure.  If out() returns

  1079    non-zero, inflateBack() will return with an error.  Neither in() nor out()

  1080    are permitted to change the contents of the window provided to

  1081    inflateBackInit(), which is also the buffer that out() uses to write from.

  1082    The length written by out() will be at most the window size.  Any non-zero

  1083    amount of input may be provided by in().

  1084 

  1085      For convenience, inflateBack() can be provided input on the first call by

  1086    setting strm->next_in and strm->avail_in.  If that input is exhausted, then

  1087    in() will be called.  Therefore strm->next_in must be initialized before

  1088    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called

  1089    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in

  1090    must also be initialized, and then if strm->avail_in is not zero, input will

  1091    initially be taken from strm->next_in[0 .. strm->avail_in - 1].

  1092 

  1093      The in_desc and out_desc parameters of inflateBack() is passed as the

  1094    first parameter of in() and out() respectively when they are called.  These

  1095    descriptors can be optionally used to pass any information that the caller-

  1096    supplied in() and out() functions need to do their job.

  1097 

  1098      On return, inflateBack() will set strm->next_in and strm->avail_in to

  1099    pass back any unused input that was provided by the last in() call.  The

  1100    return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR

  1101    if in() or out() returned an error, Z_DATA_ERROR if there was a format

  1102    error in the deflate stream (in which case strm->msg is set to indicate the

  1103    nature of the error), or Z_STREAM_ERROR if the stream was not properly

  1104    initialized.  In the case of Z_BUF_ERROR, an input or output error can be

  1105    distinguished using strm->next_in which will be Z_NULL only if in() returned

  1106    an error.  If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to

  1107    out() returning non-zero.  (in() will always be called before out(), so

  1108    strm->next_in is assured to be defined if out() returns non-zero.)  Note

  1109    that inflateBack() cannot return Z_OK.

  1110    

  1111    @param strm stream of data

  1112    @param in input function pointer

  1113    @param in_desc input parameters for in_func

  1114    @param out output function pointer

  1115    @param out_desc output parameters for out_func

  1116    @return Refer to the above description for detailed explanation

  1117 */

  1118 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,

  1119                                     in_func in, void FAR *in_desc,

  1120                                     out_func out, void FAR *out_desc));

  1121 

  1122 /**

  1123      All memory allocated by inflateBackInit() is freed.

  1124 

  1125    @param strm stream of data

  1126    @return inflateBackEnd returns Z_OK on success, or Z_STREAM_ERROR if the stream

  1127    state was inconsistent.

  1128 */

  1129 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));

  1130 

  1131 /** 

  1132  	Return flags indicating compile-time options.

  1133 

  1134     Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: