1 /*

     2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     3  *

     4  * This code is free software; you can redistribute it and/or modify it

     5  * under the terms of the GNU General Public License version 2 only, as

     6  * published by the Free Software Foundation.  Oracle designates this

     7  * particular file as subject to the "Classpath" exception as provided

     8  * by Oracle in the LICENSE file that accompanied this code.

     9  *

    10  * This code is distributed in the hope that it will be useful, but WITHOUT

    11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    13  * version 2 for more details (a copy is included in the LICENSE file that

    14  * accompanied this code).

    15  *

    16  * You should have received a copy of the GNU General Public License version

    17  * 2 along with this work; if not, write to the Free Software Foundation,

    18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    19  *

    20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    21  * or visit www.oracle.com if you need additional information or have any

    22  * questions.

    23  */

    24 

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

    26   version 1.2.3, July 18th, 2005

    27 

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

    29 

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

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

    32   arising from the use of this software.

    33 

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

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

    36   freely, subject to the following restrictions:

    37 

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

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

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

    41      appreciated but is not required.

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

    43      misrepresented as being the original software.

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

    45 

    46   Jean-loup Gailly        Mark Adler

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

    48 

    49 

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

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

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

    53 */

    54 

    55 #ifndef ZLIB_H

    56 #define ZLIB_H

    57 

    58 #include "zconf.h"

    59 

    60 #ifdef __cplusplus

    61 extern "C" {

    62 #endif

    63 

    64 #define ZLIB_VERSION "1.2.3"

    65 #define ZLIB_VERNUM 0x1230

    66 

    67 /*

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

    69   decompression functions, including integrity checks of the uncompressed

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

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

    72   stream interface.

    73 

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

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

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

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

    78   (providing more output space) before each call.

    79 

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

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

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

    83 

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

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

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

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

    88 

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

    90 

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

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

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

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

    95 

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

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

    98   crash even in case of corrupted input.

    99 */

   100 

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

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

   103 

   104 struct internal_state;

   105 

   106 typedef struct z_stream_s {

   107     Bytef    *next_in;  /* next input byte */

   108     uInt     avail_in;  /* number of bytes available at next_in */

   109     long long total_in; /* total nb of input bytes read so far */

   110 

   111     Bytef    *next_out; /* next output byte should be put there */

   112     uInt     avail_out; /* remaining free space at next_out */

   113     long long total_out;/* total nb of bytes output so far */

   114 

   115     char     *msg;      /* last error message, NULL if no error */

   116     struct internal_state FAR *state; /* not visible by applications */

   117 

   118     alloc_func zalloc;  /* used to allocate the internal state */

   119     free_func  zfree;   /* used to free the internal state */

   120     voidpf     opaque;  /* private data object passed to zalloc and zfree */

   121 

   122     int     data_type;  /* best guess about the data type: binary or text */

   123     uLong   adler;      /* adler32 value of the uncompressed data */

   124     uLong   reserved;   /* reserved for future use */

   125 } z_stream;

   126 

   127 typedef z_stream FAR *z_streamp;

   128 

   129 /*

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

   131   for more details on the meanings of these fields.

   132 */

   133 typedef struct gz_header_s {

   134     int     text;       /* true if compressed data believed to be text */

   135     uLong   time;       /* modification time */

   136     int     xflags;     /* extra flags (not used when writing a gzip file) */

   137     int     os;         /* operating system */

   138     Bytef   *extra;     /* pointer to extra field or Z_NULL if none */

   139     uInt    extra_len;  /* extra field length (valid if extra != Z_NULL) */

   140     uInt    extra_max;  /* space at extra (only when reading header) */

   141     Bytef   *name;      /* pointer to zero-terminated file name or Z_NULL */

   142     uInt    name_max;   /* space at name (only when reading header) */

   143     Bytef   *comment;   /* pointer to zero-terminated comment or Z_NULL */

   144     uInt    comm_max;   /* space at comment (only when reading header) */

   145     int     hcrc;       /* true if there was or will be a header crc */

   146     int     done;       /* true when done reading gzip header (not used

   147                            when writing a gzip file) */

   148 } gz_header;

   149 

   150 typedef gz_header FAR *gz_headerp;

   151 

   152 /*

   153    The application must update next_in and avail_in when avail_in has

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

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

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

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

   158 

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

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

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

   162    opaque value.

   163 

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

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

   166    thread safe.

   167 

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

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

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

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

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

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

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

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

   176 

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

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

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

   180    (particularly if the decompressor wants to decompress everything in

   181    a single step).

   182 */

   183 

   184                         /* constants */

   185 

   186 #define Z_NO_FLUSH      0

   187 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */

   188 #define Z_SYNC_FLUSH    2

   189 #define Z_FULL_FLUSH    3

   190 #define Z_FINISH        4

   191 #define Z_BLOCK         5

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

   193 

   194 #define Z_OK            0

   195 #define Z_STREAM_END    1

   196 #define Z_NEED_DICT     2

   197 #define Z_ERRNO        (-1)

   198 #define Z_STREAM_ERROR (-2)

   199 #define Z_DATA_ERROR   (-3)

   200 #define Z_MEM_ERROR    (-4)

   201 #define Z_BUF_ERROR    (-5)

   202 #define Z_VERSION_ERROR (-6)

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

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

   205  */

   206 

   207 #define Z_NO_COMPRESSION         0

   208 #define Z_BEST_SPEED             1

   209 #define Z_BEST_COMPRESSION       9

   210 #define Z_DEFAULT_COMPRESSION  (-1)

   211 /* compression levels */

   212 

   213 #define Z_FILTERED            1

   214 #define Z_HUFFMAN_ONLY        2

   215 #define Z_RLE                 3

   216 #define Z_FIXED               4

   217 #define Z_DEFAULT_STRATEGY    0

   218 /* compression strategy; see deflateInit2() below for details */

   219 

   220 #define Z_BINARY   0

   221 #define Z_TEXT     1

   222 #define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */

   223 #define Z_UNKNOWN  2

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

   225 

   226 #define Z_DEFLATED   8

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

   228 

   229 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */

   230 

   231 #define zlib_version zlibVersion()

   232 /* for compatibility with versions < 1.0.2 */

   233 

   234                         /* basic functions */

   235 

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

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

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

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

   240    This check is automatically made by deflateInit and inflateInit.

   241  */

   242 

   243 /*

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

   245 

   246      Initializes the internal stream state for compression. The fields

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

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

   249    use default allocation functions.

   250 

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

   252    1 gives best speed, 9 gives best compression, 0 gives no compression at

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

   254    Z_DEFAULT_COMPRESSION requests a default compromise between speed and

   255    compression (currently equivalent to level 6).

   256 

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

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

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

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

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

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

   263 */

   264 

   265 

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

   267 /*

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

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

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

   271   forced to flush.

   272 

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

   274   following actions:

   275 

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

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

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

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

   280 

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

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

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

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

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

   286 

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

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

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

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

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

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

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

   294   output buffer because there might be more output pending.

   295 

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

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

   298   maximize compression.

   299 

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

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

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

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

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

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

   306 

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

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

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

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

   311   compression.

   312 

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

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

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

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

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

   318   avail_out == 0 on return.

   319 

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

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

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

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

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

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

   326   stream are deflateReset or deflateEnd.

   327 

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

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

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

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

   332 

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

   334   so far (that is, total_in bytes).

   335 

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

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

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

   339   the compression algorithm in any manner.

   340 

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

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

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

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

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

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

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

   348   space to continue compressing.

   349 */

   350 

   351 

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

   353 /*

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

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

   356    pending output.

   357 

   358      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the

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

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

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

   362    deallocated).

   363 */

   364 

   365 

   366 /*

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

   368 

   369      Initializes the internal stream state for decompression. The fields

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

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

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

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

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

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

   376    use default allocation functions.

   377 

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

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

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

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

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

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

   384 */

   385 

   386 

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

   388 /*

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

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

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

   392   forced to flush.

   393 

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

   395   following actions:

   396 

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

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

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

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

   401 

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

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

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

   405     about the flush parameter).

   406 

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

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

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

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

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

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

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

   414   might be more output pending.

   415 

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

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

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

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

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

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

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

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

   424 

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

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

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

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

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

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

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

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

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

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

   435   less than eight.

   436 

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

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

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

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

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

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

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

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

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

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

   447 

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

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

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

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

   452   because Z_BLOCK is used.

   453 

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

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

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

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

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

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

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

   461   only if the checksum is correct.

   462 

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

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

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

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

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

   468   trailer.

   469 

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

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

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

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

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

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

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

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

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

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

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

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

   482   of the data is desired.

   483 */

   484 

   485 

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

   487 /*

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

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

   490    pending output.

   491 

   492      inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state

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

   494    static string (which must not be deallocated).

   495 */

   496 

   497                         /* Advanced functions */

   498 

   499 /*

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

   501 */

   502 

   503 /*

   504 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,

   505                                      int  level,

   506                                      int  method,

   507                                      int  windowBits,

   508                                      int  memLevel,

   509                                      int  strategy));

   510 

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

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

   513    the caller.

   514 

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

   516    this version of the library.

   517 

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

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

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

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

   522    deflateInit is used instead.

   523 

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

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

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

   527 

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

   529    16 to windowBits to write a simple gzip header and trailer around the

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

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

   532    no header crc, and the operating system will be set to 255 (unknown).  If a

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

   534 

   535      The memLevel parameter specifies how much memory should be allocated

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

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

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

   539    usage as a function of windowBits and memLevel.

   540 

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

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

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

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

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

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

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

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

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

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

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

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

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

   554    applications.

   555 

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

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

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

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

   560 */

   561 

   562 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,

   563                                              const Bytef *dictionary,

   564                                              uInt  dictLength));

   565 /*

   566      Initializes the compression dictionary from the given byte sequence

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

   568    immediately after deflateInit, deflateInit2 or deflateReset, before any

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

   570    dictionary (see inflateSetDictionary).

   571 

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

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

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

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

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

   577    with the default empty dictionary.

   578 

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

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

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

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

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

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

   585    262 bytes of the provided dictionary.

   586 

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

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

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

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

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

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

   593 

   594      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a

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

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

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

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

   599 */

   600 

   601 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,

   602                                     z_streamp source));

   603 /*

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

   605 

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

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

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

   609    by calling deflateEnd.  Note that deflateCopy duplicates the internal

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

   611    can consume lots of memory.

   612 

   613      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not

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

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

   616    destination.

   617 */

   618 

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

   620 /*

   621      This function is equivalent to deflateEnd followed by deflateInit,

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

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

   624    that may have been set by deflateInit2.

   625 

   626       deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source

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

   628 */

   629 

   630 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,

   631                                       int level,

   632                                       int strategy));

   633 /*

   634      Dynamically update the compression level and compression strategy.  The

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

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

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

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

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

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

   641 

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

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

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

   645 

   646      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source

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

   648    if strm->avail_out was zero.

   649 */

   650 

   651 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,

   652                                     int good_length,

   653                                     int max_lazy,

   654                                     int nice_length,

   655                                     int max_chain));

   656 /*

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

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

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

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

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

   662    max_lazy, good_length, nice_length, and max_chain parameters.

   663 

   664      deflateTune() can be called after deflateInit() or deflateInit2(), and

   665    returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.

   666  */

   667 

   668 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,

   669                                        uLong sourceLen));

   670 /*

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

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

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

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

   675 */

   676 

   677 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,

   678                                      int bits,

   679                                      int value));

   680 /*

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

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

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

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

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

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

   687   value will be inserted in the output.

   688 

   689       deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source

   690    stream state was inconsistent.

   691 */

   692 

   693 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,

   694                                          gz_headerp head));

   695 /*

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

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

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

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

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

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

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

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

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

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

   706    1.3.x) do not support header crc's, and will report that it is a "multi-part

   707    gzip file" and give up.

   708 

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

   710    the time set to zero, and os set to 255, with no extra, name, or comment

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

   712 

   713       deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source

   714    stream state was inconsistent.

   715 */

   716 

   717 /*

   718 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,

   719                                      int  windowBits));

   720 

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

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

   723    before by the caller.

   724 

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

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

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

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

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

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

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

   732    Z_DATA_ERROR instead of trying to allocate a larger window.

   733 

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

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

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

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

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

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

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

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

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

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

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

   745 

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

   747    32 to windowBits to enable zlib and gzip decoding with automatic header

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

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

   750    a crc32 instead of an adler32.

   751 

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

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

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

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

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

   757    and avail_out are unchanged.)

   758 */

   759 

   760 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,

   761                                              const Bytef *dictionary,

   762                                              uInt  dictLength));

   763 /*

   764      Initializes the decompression dictionary from the given uncompressed byte

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

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

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

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

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

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

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

   772    dictionary that was used for compression is provided.

   773 

   774      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a

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

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

   777    expected one (incorrect adler32 value). inflateSetDictionary does not

   778    perform any decompression: this will be done by subsequent calls of

   779    inflate().

   780 */

   781 

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

   783 /*

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

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

   786   available input is skipped. No output is provided.

   787 

   788     inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR

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

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

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

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

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

   794   until success or end of the input data.

   795 */

   796 

   797 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,

   798                                     z_streamp source));

   799 /*

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

   801 

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

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

   804    allowing restarting inflate at those points when randomly accessing the

   805    stream.

   806 

   807      inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not

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

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

   810    destination.

   811 */

   812 

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

   814 /*

   815      This function is equivalent to inflateEnd followed by inflateInit,

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

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

   818 

   819       inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source

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

   821 */

   822 

   823 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,

   824                                      int bits,

   825                                      int value));

   826 /*

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

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

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

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

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

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

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

   834 

   835       inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source

   836    stream state was inconsistent.

   837 */

   838 

   839 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,

   840                                          gz_headerp head));

   841 /*

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

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

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

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

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

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

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

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

   850    and before any actual data is decompressed.

   851 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

   867    elsewhere so that they can be eventually freed.

   868 

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

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

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

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

   873    retrieve the header from the next gzip stream.

   874 

   875       inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source

   876    stream state was inconsistent.

   877 */

   878 

   879 /*

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

   881                                         unsigned char FAR *window));

   882 

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

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

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

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

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

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

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

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

   891    deflate streams.

   892 

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

   894 

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

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

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

   898    match the version of the header file.

   899 */

   900 

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

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

   903 

   904 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,

   905                                     in_func in, void FAR *in_desc,

   906                                     out_func out, void FAR *out_desc));

   907 /*

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

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

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

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

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

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

   914 

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

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

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

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

   919    the allocated state.

   920 

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

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

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

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

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

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

   927    trailer around the deflate stream.

   928 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

   945 

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

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

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

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

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

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

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

   953 

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

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

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

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

   958 

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

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

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

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

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

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

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

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

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

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

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

   970    that inflateBack() cannot return Z_OK.

   971 */

   972 

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

   974 /*

   975      All memory allocated by inflateBackInit() is freed.

   976 

   977      inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream

   978    state was inconsistent.

   979 */

   980 

   981 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));

   982 /* Return flags indicating compile-time options.

   983 

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

   985      1.0: size of uInt

   986      3.2: size of uLong

   987      5.4: size of voidpf (pointer)

   988      7.6: size of z_off_t

   989 

   990     Compiler, assembler, and debug options:

   991      8: DEBUG

   992      9: ASMV or ASMINF -- use ASM code

   993      10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention

   994      11: 0 (reserved)

   995 

   996     One-time table building (smaller code, but not thread-safe if true):

   997      12: BUILDFIXED -- build static block decoding tables when needed

   998      13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed

   999      14,15: 0 (reserved)

  1000 

  1001     Library content (indicates missing functionality):

  1002      16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking

  1003                           deflate code when not needed)

  1004      17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect

  1005                     and decode gzip streams (to avoid linking crc code)

  1006      18-19: 0 (reserved)

  1007 

  1008     Operation variations (changes in library functionality):

  1009      20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate

  1010      21: FASTEST -- deflate algorithm with only one, lowest compression level

  1011      22,23: 0 (reserved)

  1012 

  1013     The sprintf variant used by gzprintf (zero is best):

  1014      24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format

  1015      25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!

  1016      26: 0 = returns value, 1 = void -- 1 means inferred string length returned

  1017 

  1018     Remainder:

  1019      27-31: 0 (reserved)

  1020  */

  1021 

  1022 

  1023                         /* utility functions */

  1024 

  1025 /*

  1026      The following utility functions are implemented on top of the

  1027    basic stream-oriented functions. To simplify the interface, some

  1028    default options are assumed (compression level and memory usage,

  1029    standard memory allocation functions). The source code of these

  1030    utility functions can easily be modified if you need special options.

  1031 */

  1032 

  1033 ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,

  1034                                  const Bytef *source, uLong sourceLen));

  1035 /*

  1036      Compresses the source buffer into the destination buffer.  sourceLen is

  1037    the byte length of the source buffer. Upon entry, destLen is the total

  1038    size of the destination buffer, which must be at least the value returned

  1039    by compressBound(sourceLen). Upon exit, destLen is the actual size of the

  1040    compressed buffer.

  1041      This function can be used to compress a whole file at once if the

  1042    input file is mmap'ed.

  1043      compress returns Z_OK if success, Z_MEM_ERROR if there was not

  1044    enough memory, Z_BUF_ERROR if there was not enough room in the output

  1045    buffer.

  1046 */

  1047 

  1048 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,

  1049                                   const Bytef *source, uLong sourceLen,

  1050                                   int level));

  1051 /*

  1052      Compresses the source buffer into the destination buffer. The level

  1053    parameter has the same meaning as in deflateInit.  sourceLen is the byte

  1054    length of the source buffer. Upon entry, destLen is the total size of the

  1055    destination buffer, which must be at least the value returned by

  1056    compressBound(sourceLen). Upon exit, destLen is the actual size of the

  1057    compressed buffer.

  1058 

  1059      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough

  1060    memory, Z_BUF_ERROR if there was not enough room in the output buffer,

  1061    Z_STREAM_ERROR if the level parameter is invalid.

  1062 */

  1063 

  1064 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));

  1065 /*

  1066      compressBound() returns an upper bound on the compressed size after

  1067    compress() or compress2() on sourceLen bytes.  It would be used before

  1068    a compress() or compress2() call to allocate the destination buffer.

  1069 */

  1070 

  1071 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,

  1072                                    const Bytef *source, uLong sourceLen));

  1073 /*

  1074      Decompresses the source buffer into the destination buffer.  sourceLen is

  1075    the byte length of the source buffer. Upon entry, destLen is the total

  1076    size of the destination buffer, which must be large enough to hold the

  1077    entire uncompressed data. (The size of the uncompressed data must have

  1078    been saved previously by the compressor and transmitted to the decompressor

  1079    by some mechanism outside the scope of this compression library.)

  1080    Upon exit, destLen is the actual size of the compressed buffer.

  1081      This function can be used to decompress a whole file at once if the

  1082    input file is mmap'ed.

  1083 

  1084      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not

  1085    enough memory, Z_BUF_ERROR if there was not enough room in the output

  1086    buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.

  1087 */

  1088 

  1089 

  1090 typedef voidp gzFile;

  1091 

  1092 ZEXTERN gzFile ZEXPORT gzopen  OF((const char *path, const char *mode));

  1093 /*

  1094      Opens a gzip (.gz) file for reading or writing. The mode parameter

  1095    is as in fopen ("rb" or "wb") but can also include a compression level

  1096    ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for

  1097    Huffman only compression as in "wb1h", or 'R' for run-length encoding

  1098    as in "wb1R". (See the description of deflateInit2 for more information

  1099    about the strategy parameter.)

  1100 

  1101      gzopen can be used to read a file which is not in gzip format; in this

  1102    case gzread will directly read from the file without decompression.

  1103 

  1104      gzopen returns NULL if the file could not be opened or if there was

  1105    insufficient memory to allocate the (de)compression state; errno

  1106    can be checked to distinguish the two cases (if errno is zero, the

  1107    zlib error is Z_MEM_ERROR).  */

  1108 

  1109 ZEXTERN gzFile ZEXPORT gzdopen  OF((int fd, const char *mode));

  1110 /*

  1111      gzdopen() associates a gzFile with the file descriptor fd.  File

  1112    descriptors are obtained from calls like open, dup, creat, pipe or

  1113    fileno (in the file has been previously opened with fopen).

  1114    The mode parameter is as in gzopen.

  1115      The next call of gzclose on the returned gzFile will also close the

  1116    file descriptor fd, just like fclose(fdopen(fd), mode) closes the file

  1117    descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).

  1118      gzdopen returns NULL if there was insufficient memory to allocate

  1119    the (de)compression state.

  1120 */

  1121 

  1122 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));

  1123 /*

  1124      Dynamically update the compression level or strategy. See the description

  1125    of deflateInit2 for the meaning of these parameters.

  1126      gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not

  1127    opened for writing.

  1128 */

  1129 

  1130 ZEXTERN int ZEXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));

  1131 /*

  1132      Reads the given number of uncompressed bytes from the compressed file.

  1133    If the input file was not in gzip format, gzread copies the given number

  1134    of bytes into the buffer.