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

 * All rights reserved.

 */

/** 

@file

@publishedAll

@externallyDefinedApi

*/

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

  version 1.2.3, July 18th, 2005

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

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

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

  arising from the use of this software.

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

  including commercial applications, and to alter it and redistribute it

  freely, subject to the following restrictions:

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

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

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

     appreciated but is not required.

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

     misrepresented as being the original software.

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

  Jean-loup Gailly        Mark Adler

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

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

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

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

*/

#ifndef _ZLIB_H

#define _ZLIB_H

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

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

	#include "zconf.h"

#else

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

	#include <zconf.h> 

#endif

#ifdef __cplusplus

	extern "C" {

#endif

/** Zlib version */

#define ZLIB_VERSION "1.2.3"

/** Zlib version Number */

#define ZLIB_VERNUM 0x1230

/**

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

  decompression functions, including integrity checks of the uncompressed

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

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

  stream interface.

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

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

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

  application must provide more input and/or consume the output

  (providing more output space) before each call.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  crash even in case of corrupted input.

*/

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

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

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

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

struct internal_state;

/**

	Encapsulates a zip stream

*/

typedef struct z_stream_s {

	/** Next input byte */

    Bytef    *next_in;  

    /** Number of bytes available at next_in */

    uInt     avail_in;  

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

    uLong    total_in;  

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

    Bytef    *next_out; 

    /** Remaining free space at next_out */

    uInt     avail_out; 

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

    uLong    total_out; 

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

    char     *msg;      

    /** Not visible by applications */

    struct internal_state FAR *state; 

    /** Used to allocate the internal state */

    alloc_func zalloc;  

    /** Used to free the internal state */

    free_func  zfree;   

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

    voidpf     opaque;  

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

    int     data_type;  

    /** Adler32 value of the uncompressed data */

    uLong   adler;      

    /** Reserved for future use */

    uLong   reserved;   

} z_stream;

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

typedef z_stream FAR *z_streamp;

/**

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

  for more details on the meanings of these fields.

*/

typedef struct gz_header_s {

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

    int     text;       

    /** Modification time */

    uLong   time;       

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

    int     xflags;     

    /** Operating system */

    int     os;         

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

    Bytef   *extra;     

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

    uInt    extra_len;  

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

    uInt    extra_max;  

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

    Bytef   *name;      

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

    uInt    name_max;   

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

    Bytef   *comment;   

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

    uInt    comm_max;   

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

    int     hcrc;       

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

    int     done;   

} gz_header;

/** gz_headerp is typedef gz_header* */

typedef gz_header FAR *gz_headerp;

/*

   The application must update next_in and avail_in when avail_in has

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

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

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

   compression library and must not be updated by the application.

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

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

   memory management. The compression library attaches no meaning to the

   opaque value.

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

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

   thread safe.

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

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

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

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

   have their offset normalized to zero. The default allocation function

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

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

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

   The fields total_in and total_out can be used for statistics or

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

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

   (particularly if the decompressor wants to decompress everything in

   a single step).

*/

                        /* constants */

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

#define Z_NO_FLUSH      0

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

#define Z_PARTIAL_FLUSH 1

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

#define Z_SYNC_FLUSH    2

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

#define Z_FULL_FLUSH    3

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

#define Z_FINISH        4

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

#define Z_BLOCK         5

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

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

#define Z_OK            0

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

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

#define Z_STREAM_END    1

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

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

#define Z_NEED_DICT     2

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

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

#define Z_ERRNO        (-1)

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

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

#define Z_STREAM_ERROR (-2)

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

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

#define Z_DATA_ERROR   (-3)

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

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

#define Z_MEM_ERROR    (-4)

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

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

#define Z_BUF_ERROR    (-5)

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

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

#define Z_VERSION_ERROR (-6)

/** Compression level as no compression */

#define Z_NO_COMPRESSION         0

/** Compression level for best speed */

#define Z_BEST_SPEED             1

/** Compression level for best compression */

#define Z_BEST_COMPRESSION       9

/** Compression level for default compression */

#define Z_DEFAULT_COMPRESSION  (-1)

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

#define Z_FILTERED            1

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

#define Z_HUFFMAN_ONLY        2

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

#define Z_RLE                 3

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

#define Z_FIXED               4

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

#define Z_DEFAULT_STRATEGY    0

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

#define Z_BINARY   0

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

#define Z_TEXT     1

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

#define Z_ASCII    Z_TEXT   

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

#define Z_UNKNOWN  2

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

#define Z_DEFLATED   8

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

#define Z_NULL  0  

/** For compatibility with versions < 1.0.2 */

#define zlib_version zlibVersion()

                        /* basic functions */

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

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

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

   This check is automatically made by deflateInit and inflateInit.

   @return returns zlib version 

 */

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

/*

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

     Initializes the internal stream state for compression. The fields

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

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

   use default allocation functions.

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

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

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

   Z_DEFAULT_COMPRESSION requests a default compromise between speed and

   compression (currently equivalent to level 6).

     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not

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

   Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible

   with the version assumed by the caller (ZLIB_VERSION).

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

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

*/

/**

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

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

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

  forced to flush.

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

  following actions:

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

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

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

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

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

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

    Forcing flush frequently degrades the compression ratio, so this parameter

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

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

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

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

  more output, and updating avail_in or avail_out accordingly; avail_out

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

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

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

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

  output buffer because there might be more output pending.

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

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

  maximize compression.

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

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

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

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

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

  algorithms and so it should be used only when necessary.

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

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

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

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

  compression.

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

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

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

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

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

  avail_out == 0 on return.

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

  pending output is flushed and deflate returns with Z_STREAM_END if there

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

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

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

  deflate has returned Z_STREAM_END, the only possible operations on the

  stream are deflateReset or deflateEnd.

    Z_FINISH can be used immediately after deflateInit if all the compression

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

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

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

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

  so far (that is, total_in bytes).

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

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

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

  the compression algorithm in any manner.

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

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

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

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

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

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

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

  space to continue compressing.

  @param strm Stream of data

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

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

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

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

*/

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

/**

     All dynamically allocated data structures for this stream are freed.

   This function discards any unprocessed input and does not flush any

   pending output.

     deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the

   stream state was inconsistent, Z_DATA_ERROR if the stream was freed

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

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

   deallocated).

   @param strm Stream of data

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

*/

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

/*

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

     Initializes the internal stream state for decompression. The fields

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

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

   value depends on the compression method), inflateInit determines the

   compression method from the zlib header and allocates all data structures

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

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

   use default allocation functions.

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

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

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

   message. inflateInit does not perform any decompression apart from reading

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

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

*/

/**

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

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

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

  forced to flush.

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

  following actions:

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

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

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

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

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

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

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

    about the flush parameter).

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

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

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

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

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

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

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

  might be more output pending.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  less than eight.

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

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

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

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

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

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

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

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

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

  may be used for the single inflate() call.

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

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

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

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

  because Z_BLOCK is used.

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

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

  chosen by the compressor and returns Z_NEED_DICT; otherwise it sets

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

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

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

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

  only if the checksum is correct.

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

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

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

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

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

  trailer.

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

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

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

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

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

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

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

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

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

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

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

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

  of the data is desired.

  @param strm Stream of data

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

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

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

*/

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

/**

     All dynamically allocated data structures for this stream are freed.

   This function discards any unprocessed input and does not flush any

   pending output.

  @param strm Stream of data

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

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

   static string (which must not be deallocated). 

*/

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

                        /* Advanced functions */

/*

    The following functions are needed only in some special applications.

*/

/*

ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,

                                     int  level,

                                     int  method,

                                     int  windowBits,

                                     int  memLevel,

                                     int  strategy));

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

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

   the caller.

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

   this version of the library.

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

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

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

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

   deflateInit is used instead.

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

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

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

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

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

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

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

   windowBits of 9 is used in place of 8.

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

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

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

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

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

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

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

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

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

     The memLevel parameter specifies how much memory should be allocated

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

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

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

   usage as a function of windowBits and memLevel.

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

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

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

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

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

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

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

   coding and less string matching; it is somewhat intermediate between

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

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

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

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

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

   applications.

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

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

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

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

*/

/**

     Initializes the compression dictionary from the given byte sequence

   without producing any compressed output. This function must be called

   immediately after deflateInit, deflateInit2 or deflateReset, before any

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

   dictionary (see inflateSetDictionary).

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

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

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

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

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

   with the default empty dictionary.

     Depending on the size of the compression data structures selected by

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

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

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

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

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

   262 bytes of the provided dictionary.

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

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

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

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

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

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

  @param strm Stream of data

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

  @param dictLength Dictionay Length

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

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

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

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

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

*/

ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,

                                             const Bytef *dictionary,

                                             uInt  dictLength));

/**

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

     This function can be useful when several compression strategies will be

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

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

   by calling deflateEnd.  Note that deflateCopy duplicates the internal

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

   can consume lots of memory.

   @param dest destination stream 

   @param souce source stream of data

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

   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent

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

   destination.

*/

ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,

                                    z_streamp source));

/**

     This function is equivalent to deflateEnd followed by deflateInit,

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

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

   that may have been set by deflateInit2.

   @param strm stream of data

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

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

*/

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

/**

     Dynamically update the compression level and compression strategy.  The

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

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

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

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

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

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

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

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

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

   @param strm stream of data

   @param level compression level

   @param strategy compression algorithm

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

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

   if strm->avail_out was zero.

*/

ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,

                                      int level,

                                      int strategy));

/**

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

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

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

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

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

   max_lazy, good_length, nice_length, and max_chain parameters.

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

   @param strm stream of data

   @param good_length reduce lazy search above this match length

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

   @param nice_length quit search above this match length

   @param max_chain

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

 */

ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,

                                    int good_length,

                                    int max_lazy,

                                    int nice_length,

                                    int max_chain));

/**

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

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

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

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

   @param strm stream of data

   @param sourceLen source length

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

   deflation of sourceLen bytes.

*/

ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,

                                       uLong sourceLen));

/**

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

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

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

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

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

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

  value will be inserted in the output.

   @param strm stream of data

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

   significant bits of value will be inserted in the output.

   @param value represents value of the bits to be inserted

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

   stream state was inconsistent.

*/

ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,

                                     int bits,

                                     int value));

/**

      deflateSetHeader() provides gzip header information for when a gzip

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

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

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

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

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

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

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

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

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

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

   gzip file" and give up.

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

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

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

   @param strm stream of data

   @param head gzip header

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

   stream state was inconsistent.

*/

ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,

                                         gz_headerp head));

/*

ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,

                                     int  windowBits));

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

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

   before by the caller.

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

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

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

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

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

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

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

   Z_DATA_ERROR instead of trying to allocate a larger window.

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

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

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

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

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

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

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

   windowBits of 9 is used in place of 8.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

   a crc32 instead of an adler32.

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

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

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

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

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

   and avail_out are unchanged.)

*/

/**

     Initializes the decompression dictionary from the given uncompressed byte

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

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

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

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

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

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

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

   dictionary that was used for compression is provided.

   inflateSetDictionary does not perform any decompression: this will be done 

   by subsequent calls of inflate().

   @param strm stream of data

   @param dictionary Pointer to dictionary

   @param dictLength Dictionary Length

   @return inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a

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

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

   expected one (incorrect adler32 value). 

*/

ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,

                                             const Bytef *dictionary,

                                             uInt  dictLength));

/**

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

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

  available input is skipped. No output is provided.

  @param strm Stream of data

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

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

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

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

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

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

  until success or end of the input data.

*/

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

/**

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

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

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

   allowing restarting inflate at those points when randomly accessing the

   stream.

   @param dest destination stream

   @param source source stream of data

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

   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent

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

   destination.

*/

ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,

                                    z_streamp source));

/**

     This function is equivalent to inflateEnd followed by inflateInit,

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

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

   @param strm Stream of data

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

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

*/

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

/**

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

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

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

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

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

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

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

   @param strm stream of data

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

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

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

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

   stream state was inconsistent.

*/

ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,

                                     int bits,

                                     int value));

/**

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

   provided gz_header structure.  inflateGetHeader() may be called after

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

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

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

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

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

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

   and before any actual data is decompressed.

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

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

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

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

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

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

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

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

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

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

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

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

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