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

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    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 1.2.5, April 19th, 2010

    27 

    28   Copyright (C) 1995-2010 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 "1.2.5"

    65 #define ZLIB_VERNUM 0x1250

    66 #define ZLIB_VER_MAJOR 1

    67 #define ZLIB_VER_MINOR 2

    68 #define ZLIB_VER_REVISION 5

    69 #define ZLIB_VER_SUBREVISION 0

    70 

    71 /*

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

    73   decompression functions, including integrity checks of the uncompressed data.

    74   This version of the library supports only one compression method (deflation)

    75   but other algorithms will be added later and will have the same stream

    76   interface.

    77 

    78     Compression can be done in a single step if the buffers are large enough,

    79   or can be done by repeated calls of the compression function.  In the latter

    80   case, the application must provide more input and/or consume the output

    81   (providing more output space) before each call.

    82 

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

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

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

    86 

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

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

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

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

    91 

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

    93 

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

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

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

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

    98 

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

   100   the consistency of the compressed data, so the library should never crash

   101   even in case of corrupted input.

   102 */

   103 

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

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

   106 

   107 struct internal_state;

   108 

   109 typedef struct z_stream_s {

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

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

   112     uLong    total_in;  /* total nb of input bytes read so far */

   113 

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

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

   116     uLong    total_out; /* total nb of bytes output so far */

   117 

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

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

   120 

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

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

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

   124 

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

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

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

   128 } z_stream;

   129 

   130 typedef z_stream FAR *z_streamp;

   131 

   132 /*

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

   134   for more details on the meanings of these fields.

   135 */

   136 typedef struct gz_header_s {

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

   138     uLong   time;       /* modification time */

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

   140     int     os;         /* operating system */

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

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

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

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

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

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

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

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

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

   150                            when writing a gzip file) */

   151 } gz_header;

   152 

   153 typedef gz_header FAR *gz_headerp;

   154 

   155 /*

   156      The application must update next_in and avail_in when avail_in has dropped

   157    to zero.  It must update next_out and avail_out when avail_out has dropped

   158    to zero.  The application must initialize zalloc, zfree and opaque before

   159    calling the init function.  All other fields are set by the compression

   160    library and must not be updated by the application.

   161 

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

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

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

   165    opaque value.

   166 

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

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

   169    thread safe.

   170 

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

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

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

   174    returned by zalloc for objects of exactly 65536 bytes *must* have their

   175    offset normalized to zero.  The default allocation function provided by this

   176    library ensures this (see zutil.c).  To reduce memory requirements and avoid

   177    any allocation of 64K objects, at the expense of compression ratio, compile

   178    the library with -DMAX_WBITS=14 (see zconf.h).

   179 

   180      The fields total_in and total_out can be used for statistics or progress

   181    reports.  After compression, total_in holds the total size of the

   182    uncompressed data and may be saved for use in the decompressor (particularly

   183    if the decompressor wants to decompress everything in a single step).

   184 */

   185 

   186                         /* constants */

   187 

   188 #define Z_NO_FLUSH      0

   189 #define Z_PARTIAL_FLUSH 1

   190 #define Z_SYNC_FLUSH    2

   191 #define Z_FULL_FLUSH    3

   192 #define Z_FINISH        4

   193 #define Z_BLOCK         5

   194 #define Z_TREES         6

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

   196 

   197 #define Z_OK            0

   198 #define Z_STREAM_END    1

   199 #define Z_NEED_DICT     2

   200 #define Z_ERRNO        (-1)

   201 #define Z_STREAM_ERROR (-2)

   202 #define Z_DATA_ERROR   (-3)

   203 #define Z_MEM_ERROR    (-4)

   204 #define Z_BUF_ERROR    (-5)

   205 #define Z_VERSION_ERROR (-6)

   206 /* Return codes for the compression/decompression functions. Negative values

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

   208  */

   209 

   210 #define Z_NO_COMPRESSION         0

   211 #define Z_BEST_SPEED             1

   212 #define Z_BEST_COMPRESSION       9

   213 #define Z_DEFAULT_COMPRESSION  (-1)

   214 /* compression levels */

   215 

   216 #define Z_FILTERED            1

   217 #define Z_HUFFMAN_ONLY        2

   218 #define Z_RLE                 3

   219 #define Z_FIXED               4

   220 #define Z_DEFAULT_STRATEGY    0

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

   222 

   223 #define Z_BINARY   0

   224 #define Z_TEXT     1

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

   226 #define Z_UNKNOWN  2

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

   228 

   229 #define Z_DEFLATED   8

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

   231 

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

   233 

   234 #define zlib_version zlibVersion()

   235 /* for compatibility with versions < 1.0.2 */

   236 

   237 

   238                         /* basic functions */

   239 

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

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

   242    If the first character differs, the library code actually used is not

   243    compatible with the zlib.h header file used by the application.  This check

   244    is automatically made by deflateInit and inflateInit.

   245  */

   246 

   247 /*

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

   249 

   250      Initializes the internal stream state for compression.  The fields

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

   252    zalloc and zfree are set to Z_NULL, deflateInit updates them to use default

   253    allocation functions.

   254 

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

   256    1 gives best speed, 9 gives best compression, 0 gives no compression at all

   257    (the input data is simply copied a block at a time).  Z_DEFAULT_COMPRESSION

   258    requests a default compromise between speed and compression (currently

   259    equivalent to level 6).

   260 

   261      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough

   262    memory, Z_STREAM_ERROR if level is not a valid compression level, or

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

   264    with the version assumed by the caller (ZLIB_VERSION).  msg is set to null

   265    if there is no error message.  deflateInit does not perform any compression:

   266    this will be done by deflate().

   267 */

   268 

   269 

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

   271 /*

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

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

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

   275   forced to flush.

   276 

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

   278   following actions:

   279 

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

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

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

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

   284 

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

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

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

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

   289     output may be provided even if flush is not set.

   290 

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

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

   293   output, and updating avail_in or avail_out accordingly; avail_out should

   294   never be zero before the call.  The application can consume the compressed

   295   output when it wants, for example when the output buffer is full (avail_out

   296   == 0), or after each call of deflate().  If deflate returns Z_OK and with

   297   zero avail_out, it must be called again after making room in the output

   298   buffer because there might be more output pending.

   299 

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

   301   decide how much data to accumulate before producing output, in order to

   302   maximize compression.

   303 

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

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

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

   307   particular avail_in is zero after the call if enough output space has been

   308   provided before the call.) Flushing may degrade compression for some

   309   compression algorithms and so it should be used only when necessary.  This

   310   completes the current deflate block and follows it with an empty stored block

   311   that is three bits plus filler bits to the next byte, followed by four bytes

   312   (00 00 ff ff).

   313 

   314     If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the

   315   output buffer, but the output is not aligned to a byte boundary.  All of the

   316   input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.

   317   This completes the current deflate block and follows it with an empty fixed

   318   codes block that is 10 bits long.  This assures that enough bytes are output

   319   in order for the decompressor to finish the block before the empty fixed code

   320   block.

   321 

   322     If flush is set to Z_BLOCK, a deflate block is completed and emitted, as

   323   for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to

   324   seven bits of the current block are held to be written as the next byte after

   325   the next deflate block is completed.  In this case, the decompressor may not

   326   be provided enough bits at this point in order to complete decompression of

   327   the data provided so far to the compressor.  It may need to wait for the next

   328   block to be emitted.  This is for advanced applications that need to control

   329   the emission of deflate blocks.

   330 

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

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

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

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

   335   compression.

   336 

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

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

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

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

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

   342   avail_out == 0 on return.

   343 

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

   345   pending output is flushed and deflate returns with Z_STREAM_END if there was

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

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

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

   349   deflate has returned Z_STREAM_END, the only possible operations on the stream

   350   are deflateReset or deflateEnd.

   351 

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

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

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

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

   356 

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

   358   so far (that is, total_in bytes).

   359 

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

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

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

   363   compression algorithm in any manner.

   364 

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

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

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

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

   369   if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible

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

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

   372   space to continue compressing.

   373 */

   374 

   375 

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

   377 /*

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

   379    This function discards any unprocessed input and does not flush any pending

   380    output.

   381 

   382      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the

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

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

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

   386    deallocated).

   387 */

   388 

   389 

   390 /*

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

   392 

   393      Initializes the internal stream state for decompression.  The fields

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

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

   396    exact value depends on the compression method), inflateInit determines the

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

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

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

   400    use default allocation functions.

   401 

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

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

   404    version assumed by the caller, or Z_STREAM_ERROR if the parameters are

   405    invalid, such as a null pointer to the structure.  msg is set to null if

   406    there is no error message.  inflateInit does not perform any decompression

   407    apart from possibly reading the zlib header if present: actual decompression

   408    will be done by inflate().  (So next_in and avail_in may be modified, but

   409    next_out and avail_out are unused and unchanged.) The current implementation

   410    of inflateInit() does not process any header information -- that is deferred

   411    until inflate() is called.

   412 */

   413 

   414 

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

   416 /*

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

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

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

   420   forced to flush.

   421 

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

   423   following actions:

   424 

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

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

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

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

   429 

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

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

   432     no more input data or no more space in the output buffer (see below about

   433     the flush parameter).

   434 

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

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

   437   output, and updating the next_* and avail_* values accordingly.  The

   438   application can consume the uncompressed output when it wants, for example

   439   when the output buffer is full (avail_out == 0), or after each call of

   440   inflate().  If inflate returns Z_OK and with zero avail_out, it must be

   441   called again after making room in the output buffer because there might be

   442   more output pending.

   443 

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

   445   Z_BLOCK, or Z_TREES.  Z_SYNC_FLUSH requests that inflate() flush as much

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

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

   448   the zlib or gzip format, this will cause inflate() to return immediately

   449   after the header and before the first block.  When doing a raw inflate,

   450   inflate() will go ahead and process the first block, and will return when it

   451   gets to the end of that block, or when it runs out of data.

   452 

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

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

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

   456   inflate() is currently decoding the last block in the deflate stream, plus

   457   128 if inflate() returned immediately after decoding an end-of-block code or

   458   decoding the complete header up to just before the first byte of the deflate

   459   stream.  The end-of-block will not be indicated until all of the uncompressed

   460   data from that block has been written to strm->next_out.  The number of

   461   unused bits may in general be greater than seven, except when bit 7 of

   462   data_type is set, in which case the number of unused bits will be less than

   463   eight.  data_type is set as noted here every time inflate() returns for all

   464   flush options, and so can be used to determine the amount of currently

   465   consumed input in bits.

   466 

   467     The Z_TREES option behaves as Z_BLOCK does, but it also returns when the

   468   end of each deflate block header is reached, before any actual data in that

   469   block is decoded.  This allows the caller to determine the length of the

   470   deflate block header for later use in random access within a deflate block.

   471   256 is added to the value of strm->data_type when inflate() returns

   472   immediately after reaching the end of the deflate block header.

   473 

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

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

   476   single call of inflate), the parameter flush should be set to Z_FINISH.  In

   477   this case all pending input is processed and all pending output is flushed;

   478   avail_out must be large enough to hold all the uncompressed data.  (The size

   479   of the uncompressed data may have been saved by the compressor for this

   480   purpose.) The next operation on this stream must be inflateEnd to deallocate

   481   the decompression state.  The use of Z_FINISH is never required, but can be

   482   used to inform inflate that a faster approach may be used for the single

   483   inflate() call.

   484 

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

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

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

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

   489   because Z_BLOCK or Z_TREES is used.

   490 

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

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

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

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

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

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

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

   498   only if the checksum is correct.

   499 

   500     inflate() can decompress and check either zlib-wrapped or gzip-wrapped

   501   deflate data.  The header type is detected automatically, if requested when

   502   initializing with inflateInit2().  Any information contained in the gzip

   503   header is not retained, so applications that need that information should

   504   instead use raw inflate, see inflateInit2() below, or inflateBack() and

   505   perform their own processing of the gzip header and trailer.

   506 

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

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

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

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

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

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

   513   next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,

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

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

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

   517   continue decompressing.  If Z_DATA_ERROR is returned, the application may

   518   then call inflateSync() to look for a good compression block if a partial

   519   recovery of the data is desired.

   520 */

   521 

   522 

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

   524 /*

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

   526    This function discards any unprocessed input and does not flush any pending

   527    output.

   528 

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

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

   531    static string (which must not be deallocated).

   532 */

   533 

   534 

   535                         /* Advanced functions */

   536 

   537 /*

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

   539 */

   540 

   541 /*

   542 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,

   543                                      int  level,

   544                                      int  method,

   545                                      int  windowBits,

   546                                      int  memLevel,

   547                                      int  strategy));

   548 

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

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

   551    caller.

   552 

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

   554    this version of the library.

   555 

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

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

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

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

   560    deflateInit is used instead.

   561 

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

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

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

   565 

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

   567    16 to windowBits to write a simple gzip header and trailer around the

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

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

   570    header crc, and the operating system will be set to 255 (unknown).  If a

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

   572 

   573      The memLevel parameter specifies how much memory should be allocated

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

   575    slow and reduces compression ratio; memLevel=9 uses maximum memory for

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

   577    as a function of windowBits and memLevel.

   578 

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

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

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

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

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

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

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

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

   587    Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY.  Z_RLE is designed to be almost as

   588    fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data.  The

   589    strategy parameter only affects the compression ratio but not the

   590    correctness of the compressed output even if it is not set appropriately.

   591    Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler

   592    decoder for special applications.

   593 

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

   595    memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid

   596    method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is

   597    incompatible with the version assumed by the caller (ZLIB_VERSION).  msg is

   598    set to null if there is no error message.  deflateInit2 does not perform any

   599    compression: this will be done by deflate().

   600 */

   601 

   602 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,

   603                                              const Bytef *dictionary,

   604                                              uInt  dictLength));

   605 /*

   606      Initializes the compression dictionary from the given byte sequence

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

   608    immediately after deflateInit, deflateInit2 or deflateReset, before any call

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

   610    dictionary (see inflateSetDictionary).

   611 

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

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

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

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

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

   617    with the default empty dictionary.

   618 

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

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

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

   622    provided in deflateInit or deflateInit2.  Thus the strings most likely to be

   623    useful should be put at the end of the dictionary, not at the front.  In

   624    addition, the current implementation of deflate will use at most the window

   625    size minus 262 bytes of the provided dictionary.

   626 

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

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

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

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

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

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

   633 

   634      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a

   635    parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is

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

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

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

   639 */

   640 

   641 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,

   642                                     z_streamp source));

   643 /*

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

   645 

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

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

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

   649    by calling deflateEnd.  Note that deflateCopy duplicates the internal

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

   651    consume lots of memory.

   652 

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

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

   655    (such as zalloc being Z_NULL).  msg is left unchanged in both source and

   656    destination.

   657 */

   658 

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

   660 /*

   661      This function is equivalent to deflateEnd followed by deflateInit,

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

   663    stream will keep the same compression level and any other attributes that

   664    may have been set by deflateInit2.

   665 

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

   667    stream state was inconsistent (such as zalloc or state being Z_NULL).

   668 */

   669 

   670 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,

   671                                       int level,

   672                                       int strategy));

   673 /*

   674      Dynamically update the compression level and compression strategy.  The

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

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

   677    to switch to a different kind of input data requiring a different strategy.

   678    If the compression level is changed, the input available so far is

   679    compressed with the old level (and may be flushed); the new level will take

   680    effect only at the next call of deflate().

   681 

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

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

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

   685 

   686      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source

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

   688    strm->avail_out was zero.

   689 */

   690 

   691 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,

   692                                     int good_length,

   693                                     int max_lazy,

   694                                     int nice_length,

   695                                     int max_chain));

   696 /*

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

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

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

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

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

   702    max_lazy, good_length, nice_length, and max_chain parameters.

   703 

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

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

   706  */

   707 

   708 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,

   709                                        uLong sourceLen));

   710 /*

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

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

   713    deflateInit2(), and after deflateSetHeader(), if used.  This would be used

   714    to allocate an output buffer for deflation in a single pass, and so would be

   715    called before deflate().

   716 */

   717 

   718 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,

   719                                      int bits,

   720                                      int value));

   721 /*

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

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

   724    leftover from a previous deflate stream when appending to it.  As such, this

   725    function can only be used for raw deflate, and must be used before the first

   726    deflate() call after a deflateInit2() or deflateReset().  bits must be less

   727    than or equal to 16, and that many of the least significant bits of value

   728    will be inserted in the output.

   729 

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

   731    stream state was inconsistent.

   732 */

   733 

   734 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,

   735                                          gz_headerp head));

   736 /*

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

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

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

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

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

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

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

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

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

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

   747    1.3.x) do not support header crc's, and will report that it is a "multi-part

   748    gzip file" and give up.

   749 

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

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

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

   753 

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

   755    stream state was inconsistent.

   756 */

   757 

   758 /*

   759 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,

   760                                      int  windowBits));

   761 

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

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

   764    before by the caller.

   765 

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

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

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

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

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

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

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

   773    Z_DATA_ERROR instead of trying to allocate a larger window.

   774 

   775      windowBits can also be zero to request that inflate use the window size in

   776    the zlib header of the compressed stream.

   777 

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

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

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

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

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

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

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

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

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

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

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

   789 

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

   791    32 to windowBits to enable zlib and gzip decoding with automatic header

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

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

   794    crc32 instead of an adler32.

   795 

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

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

   798    version assumed by the caller, or Z_STREAM_ERROR if the parameters are

   799    invalid, such as a null pointer to the structure.  msg is set to null if

   800    there is no error message.  inflateInit2 does not perform any decompression

   801    apart from possibly reading the zlib header if present: actual decompression

   802    will be done by inflate().  (So next_in and avail_in may be modified, but

   803    next_out and avail_out are unused and unchanged.) The current implementation

   804    of inflateInit2() does not process any header information -- that is

   805    deferred until inflate() is called.

   806 */

   807 

   808 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,

   809                                              const Bytef *dictionary,

   810                                              uInt  dictLength));

   811 /*

   812      Initializes the decompression dictionary from the given uncompressed byte

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

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

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

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

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

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

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

   820    dictionary that was used for compression is provided.

   821 

   822      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a

   823    parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is

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

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

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

   827    inflate().

   828 */

   829 

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

   831 /*

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

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

   834    available input is skipped.  No output is provided.

   835 

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

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

   838    found, or Z_STREAM_ERROR if the stream structure was inconsistent.  In the

   839    success case, the application may save the current current value of total_in

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

   841    the application may repeatedly call inflateSync, providing more input each

   842    time, until success or end of the input data.

   843 */

   844 

   845 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,

   846                                     z_streamp source));

   847 /*

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

   849 

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

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

   852    allowing restarting inflate at those points when randomly accessing the

   853    stream.

   854 

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

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

   857    (such as zalloc being Z_NULL).  msg is left unchanged in both source and

   858    destination.

   859 */

   860 

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

   862 /*

   863      This function is equivalent to inflateEnd followed by inflateInit,

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

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

   866 

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

   868    stream state was inconsistent (such as zalloc or state being Z_NULL).

   869 */

   870 

   871 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,

   872                                       int windowBits));

   873 /*

   874      This function is the same as inflateReset, but it also permits changing

   875    the wrap and window size requests.  The windowBits parameter is interpreted

   876    the same as it is for inflateInit2.

   877 

   878      inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source

   879    stream state was inconsistent (such as zalloc or state being Z_NULL), or if

   880    the windowBits parameter is invalid.

   881 */

   882 

   883 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,

   884                                      int bits,

   885                                      int value));

   886 /*

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

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

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

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

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

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

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

   894 

   895      If bits is negative, then the input stream bit buffer is emptied.  Then

   896    inflatePrime() can be called again to put bits in the buffer.  This is used

   897    to clear out bits leftover after feeding inflate a block description prior

   898    to feeding inflate codes.

   899 

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

   901    stream state was inconsistent.

   902 */

   903 

   904 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));

   905 /*

   906      This function returns two values, one in the lower 16 bits of the return

   907    value, and the other in the remaining upper bits, obtained by shifting the

   908    return value down 16 bits.  If the upper value is -1 and the lower value is

   909    zero, then inflate() is currently decoding information outside of a block.

   910    If the upper value is -1 and the lower value is non-zero, then inflate is in

   911    the middle of a stored block, with the lower value equaling the number of

   912    bytes from the input remaining to copy.  If the upper value is not -1, then

   913    it is the number of bits back from the current bit position in the input of

   914    the code (literal or length/distance pair) currently being processed.  In

   915    that case the lower value is the number of bytes already emitted for that

   916    code.

   917 

   918      A code is being processed if inflate is waiting for more input to complete

   919    decoding of the code, or if it has completed decoding but is waiting for

   920    more output space to write the literal or match data.

   921 

   922      inflateMark() is used to mark locations in the input data for random

   923    access, which may be at bit positions, and to note those cases where the

   924    output of a code may span boundaries of random access blocks.  The current

   925    location in the input stream can be determined from avail_in and data_type

   926    as noted in the description for the Z_BLOCK flush parameter for inflate.

   927 

   928      inflateMark returns the value noted above or -1 << 16 if the provided

   929    source stream state was inconsistent.

   930 */

   931 

   932 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,

   933                                          gz_headerp head));

   934 /*

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

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

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

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

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

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

   941    no gzip header information forthcoming.  Note that Z_BLOCK or Z_TREES can be

   942    used to force inflate() to return immediately after header processing is

   943    complete and before any actual data is decompressed.

   944 

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

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

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

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

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

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

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

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

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

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

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

   956    present in the header, then that field is set to Z_NULL to signal its

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

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

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

   960    elsewhere so that they can be eventually freed.

   961 

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

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

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

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

   966    retrieve the header from the next gzip stream.

   967 

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

   969    stream state was inconsistent.

   970 */

   971 

   972 /*

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

   974                                         unsigned char FAR *window));

   975 

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

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

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

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

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

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

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

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

   984    deflate streams.

   985 

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

   987 

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

   989    the paramaters are invalid, Z_MEM_ERROR if the internal state could not be

   990    allocated, or Z_VERSION_ERROR if the version of the library does not match

   991    the version of the header file.

   992 */

   993 

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

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

   996 

   997 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,

   998                                     in_func in, void FAR *in_desc,

   999                                     out_func out, void FAR *out_desc));

  1000 /*

  1001      inflateBack() does a raw inflate with a single call using a call-back

  1002    interface for input and output.  This is more efficient than inflate() for

  1003    file i/o applications in that it avoids copying between the output and the

  1004    sliding window by simply making the window itself the output buffer.  This

  1005    function trusts the application to not change the output buffer passed by

  1006    the output function, at least until inflateBack() returns.

  1007 

  1008      inflateBackInit() must be called first to allocate the internal state

  1009    and to initialize the state with the user-provided window buffer.

  1010    inflateBack() may then be used multiple times to inflate a complete, raw

  1011    deflate stream with each call.  inflateBackEnd() is then called to free the

  1012    allocated state.

  1013 

  1014      A raw deflate stream is one with no zlib or gzip header or trailer.

  1015    This routine would normally be used in a utility that reads zip or gzip

  1016    files and writes out uncompressed files.  The utility would decode the

  1017    header and process the trailer on its own, hence this routine expects only

  1018    the raw deflate stream to decompress.  This is different from the normal

  1019    behavior of inflate(), which expects either a zlib or gzip header and

  1020    trailer around the deflate stream.

  1021 

  1022      inflateBack() uses two subroutines supplied by the caller that are then

  1023    called by inflateBack() for input and output.  inflateBack() calls those

  1024    routines until it reads a complete deflate stream and writes out all of the

  1025    uncompressed data, or until it encounters an error.  The function's

  1026    parameters and return types are defined above in the in_func and out_func

  1027    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the

  1028    number of bytes of provided input, and a pointer to that input in buf.  If

  1029    there is no input available, in() must return zero--buf is ignored in that

  1030    case--and inflateBack() will return a buffer error.  inflateBack() will call

  1031    out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()

  1032    should return zero on success, or non-zero on failure.  If out() returns

  1033    non-zero, inflateBack() will return with an error.  Neither in() nor out()

  1034    are permitted to change the contents of the window provided to

  1035    inflateBackInit(), which is also the buffer that out() uses to write from.

  1036    The length written by out() will be at most the window size.  Any non-zero

  1037    amount of input may be provided by in().

  1038 

  1039      For convenience, inflateBack() can be provided input on the first call by

  1040    setting strm->next_in and strm->avail_in.  If that input is exhausted, then

  1041    in() will be called.  Therefore strm->next_in must be initialized before

  1042    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called

  1043    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in

  1044    must also be initialized, and then if strm->avail_in is not zero, input will

  1045    initially be taken from strm->next_in[0 ..  strm->avail_in - 1].

  1046 

  1047      The in_desc and out_desc parameters of inflateBack() is passed as the

  1048    first parameter of in() and out() respectively when they are called.  These

  1049    descriptors can be optionally used to pass any information that the caller-

  1050    supplied in() and out() functions need to do their job.

  1051 

  1052      On return, inflateBack() will set strm->next_in and strm->avail_in to

  1053    pass back any unused input that was provided by the last in() call.  The

  1054    return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR

  1055    if in() or out() returned an error, Z_DATA_ERROR if there was a format error

  1056    in the deflate stream (in which case strm->msg is set to indicate the nature

  1057    of the error), or Z_STREAM_ERROR if the stream was not properly initialized.

  1058    In the case of Z_BUF_ERROR, an input or output error can be distinguished

  1059    using strm->next_in which will be Z_NULL only if in() returned an error.  If

  1060    strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning

  1061    non-zero.  (in() will always be called before out(), so strm->next_in is

  1062    assured to be defined if out() returns non-zero.) Note that inflateBack()

  1063    cannot return Z_OK.

  1064 */

  1065 

  1066 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));

  1067 /*

  1068      All memory allocated by inflateBackInit() is freed.

  1069 

  1070      inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream

  1071    state was inconsistent.

  1072 */

  1073 

  1074 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));

  1075 /* Return flags indicating compile-time options.

  1076 

  1077     Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:

  1078      1.0: size of uInt

  1079      3.2: size of uLong

  1080      5.4: size of voidpf (pointer)

  1081      7.6: size of z_off_t

  1082 

  1083     Compiler, assembler, and debug options:

  1084      8: DEBUG

  1085      9: ASMV or ASMINF -- use ASM code

  1086      10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention

  1087      11: 0 (reserved)

  1088 

  1089     One-time table building (smaller code, but not thread-safe if true):

  1090      12: BUILDFIXED -- build static block decoding tables when needed

  1091      13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed

  1092      14,15: 0 (reserved)

  1093 

  1094     Library content (indicates missing functionality):

  1095      16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking

  1096                           deflate code when not needed)

  1097      17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect

  1098                     and decode gzip streams (to avoid linking crc code)

  1099      18-19: 0 (reserved)

  1100 

  1101     Operation variations (changes in library functionality):

  1102      20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate

  1103      21: FASTEST -- deflate algorithm with only one, lowest compression level

  1104      22,23: 0 (reserved)

  1105 

  1106     The sprintf variant used by gzprintf (zero is best):

  1107      24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format

  1108      25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!

  1109      26: 0 = returns value, 1 = void -- 1 means inferred string length returned

  1110 

  1111     Remainder:

  1112      27-31: 0 (reserved)

  1113  */

  1114 

  1115 

  1116                         /* utility functions */

  1117 

  1118 /*

  1119      The following utility functions are implemented on top of the basic

  1120    stream-oriented functions.  To simplify the interface, some default options

  1121    are assumed (compression level and memory usage, standard memory allocation

  1122    functions).  The source code of these utility functions can be modified if

  1123    you need special options.

  1124 */

  1125 

  1126 ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,

  1127                                  const Bytef *source, uLong sourceLen));

  1128 /*

  1129      Compresses the source buffer into the destination buffer.  sourceLen is

  1130    the byte length of the source buffer.  Upon entry, destLen is the total size

  1131    of the destination buffer, which must be at least the value returned by

  1132    compressBound(sourceLen).  Upon exit, destLen is the actual size of the

  1133    compressed buffer.

  1134