/*
 * zlib.h -- interface of the 'zlib' general purpose compression library
 * version 1.1.4, March 11th, 2002
 * 
 * Copyright (C) 1995-2002 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 ftp://ds.internic.net/rfc/rfc1950.txt
 * (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
 */

#ifndef _ZLIB_H
#  define _ZLIB_H

#  include "zconf.h"

#  ifdef __cplusplus
extern        "C" {
#  endif

#  define ZLIB_VERSION "1.1.4"

    /*
     * 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 library also supports reading and writing files in gzip (.gz) format
     * with an interface similar to that of stdio.
     * 
     * 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.
     */

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

    struct internal_state;

    typedef struct z_stream_s {
        Bytef        *next_in;         /* next input byte */
        uInt          avail_in;        /* number of bytes available at next_in */
        uLong         total_in;        /* total nb of input bytes read so far */

        Bytef        *next_out;        /* next output byte should be put there */
        uInt          avail_out;       /* remaining free space at next_out */
        uLong         total_out;       /* total nb of bytes output so far */

        char         *msg;             /* last error message, NULL if no error */
        struct internal_state FAR *state;       /* not visible by applications */

        alloc_func    zalloc;          /* used to allocate the internal state */
        free_func     zfree;           /* used to free the internal state */
        voidpf        opaque;          /* private data object passed to zalloc and zfree */

        int           data_type;       /* best guess about the data type: ascii or binary */
        uLong         adler;           /* adler32 value of the uncompressed data */
        uLong         reserved;        /* reserved for future use */
    } z_stream;

    typedef z_stream FAR *z_streamp;

    /*
     * 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 
     */

#  define Z_NO_FLUSH      0
#  define Z_PARTIAL_FLUSH 1            /* will be removed, use Z_SYNC_FLUSH instead */
#  define Z_SYNC_FLUSH    2
#  define Z_FULL_FLUSH    3
#  define Z_FINISH        4
    /*
     * Allowed flush values; see deflate() below for details 
     */

#  define Z_OK            0
#  define Z_STREAM_END    1
#  define Z_NEED_DICT     2
#  define Z_ERRNO        (-1)
#  define Z_STREAM_ERROR (-2)
#  define Z_DATA_ERROR   (-3)
#  define Z_MEM_ERROR    (-4)
#  define Z_BUF_ERROR    (-5)
#  define Z_VERSION_ERROR (-6)
    /*
     * Return codes for the compression/decompression functions. Negative
     * * values are errors, positive values are used for special but normal events.
     */

#  define Z_NO_COMPRESSION         0
#  define Z_BEST_SPEED             1
#  define Z_BEST_COMPRESSION       9
#  define Z_DEFAULT_COMPRESSION  (-1)
    /*
     * compression levels 
     */

#  define Z_FILTERED            1
#  define Z_HUFFMAN_ONLY        2
#  define Z_DEFAULT_STRATEGY    0
    /*
     * compression strategy; see deflateInit2() below for details 
     */

#  define Z_BINARY   0
#  define Z_ASCII    1
#  define Z_UNKNOWN  2
    /*
     * Possible values of the data_type field 
     */

#  define Z_DEFLATED   8
    /*
     * The deflate compression method (the only one supported in this version) 
     */

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

#  define zlib_version zlibVersion()
    /*
     * for compatibility with versions < 1.0.2 
     */

    /*
     * basic functions 
     */

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

    /*
     * 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().
     */

    ZEXTERN int ZEXPORT deflate OF ((z_streamp strm, int flush));
    /*
     * 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.
     * 
     * 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
     * the 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).
     * 
     * 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
     * 0.1% larger than avail_in plus 12 bytes.  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 data_type if it can make a good guess about
     * the input data type (Z_ASCII or Z_BINARY). 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).
     */

    ZEXTERN int ZEXPORT deflateEnd OF ((z_streamp strm));
    /*
     * 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).
     */

    /*
     * 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.)
     */

    ZEXTERN int ZEXPORT inflate OF ((z_streamp strm, int flush));
    /*
     * inflate decompresses as much data as possible, and stops when the input
     * buffer becomes empty or the output buffer becomes full. It may some
     * 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.
     * 
     * If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
     * output as possible to the output buffer. The flushing behavior of inflate is
     * not specified for values of the flush parameter other than Z_SYNC_FLUSH
     * and Z_FINISH, but the current implementation actually flushes as much output
     * as possible anyway.
     * 
     * 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 routine
     * may be used for the single inflate() call.
     * 
     * If a preset dictionary is needed at this point (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() 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
     * adler32 checksum), 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. In the Z_DATA_ERROR
     * case, the application may then call inflateSync to look for a good
     * compression block.
     */

    ZEXTERN int ZEXPORT inflateEnd OF ((z_streamp strm));
    /*
     * All dynamically allocated data structures for this stream are freed.
     * This function discards any unprocessed input and does not flush any
     * pending output.
     * 
     * 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).
     */

    /*
     * 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.
     * 
     * 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), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
     * string match).  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. The strategy parameter only affects
     * the compression ratio but not the correctness of the compressed output even
     * if it is not set appropriately.
     * 
     * 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().
     */

    ZEXTERN int ZEXPORT deflateSetDictionary OF ((z_streamp strm, const Bytef * dictionary, uInt dictLength));
    /*
     * 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.
     * 
     * 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.)
     * 
     * 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 deflateCopy OF ((z_streamp dest, z_streamp source));
    /*
     * 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.
     * 
     * 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 deflateReset OF ((z_streamp strm));
    /*
     * 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.
     * 
     * 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 deflateParams OF ((z_streamp strm, int level, int strategy));
    /*
     * 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.
     * 
     * 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 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. 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.
     * 
     * 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 negative
     * memLevel). 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.)
     */

    ZEXTERN int ZEXPORT inflateSetDictionary OF ((z_streamp strm, const Bytef * dictionary, uInt dictLength));
    /*
     * Initializes the decompression dictionary from the given uncompressed byte
     * sequence. This function must be called immediately after a call of inflate
     * if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
     * can be determined from the Adler32 value returned by this call of
     * inflate. The compressor and decompressor must use exactly the same
     * dictionary (see deflateSetDictionary).
     * 
     * 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). inflateSetDictionary does not
     * perform any decompression: this will be done by subsequent calls of
     * inflate().
     */

    ZEXTERN int ZEXPORT inflateSync OF ((z_streamp strm));
    /*
     * 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.
     * 
     * 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 inflateReset OF ((z_streamp strm));
    /*
     * 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.
     * 
     * inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
     * stream state was inconsistent (such as zalloc or state being NULL).
     */

    /*
     * utility functions 
     */

    /*
     * The following utility functions are implemented on top of the
     * basic stream-oriented functions. To simplify the interface, some
     * default options are assumed (compression level and memory usage,
     * standard memory allocation functions). The source code of these
     * utility functions can easily be modified if you need special options.
     */

    ZEXTERN int ZEXPORT compress OF ((Bytef * dest, uLongf * destLen, const Bytef * source, uLong sourceLen));
    /*
     * Compresses the source buffer into the destination buffer.  sourceLen is
     * the byte length of the source buffer. Upon entry, destLen is the total
     * size of the destination buffer, which must be at least 0.1% larger than
     * sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
     * compressed buffer.
     * This function can be used to compress a whole file at once if the
     * input file is mmap'ed.
     * compress returns Z_OK if success, Z_MEM_ERROR if there was not
     * enough memory, Z_BUF_ERROR if there was not enough room in the output
     * buffer.
     */

    ZEXTERN int ZEXPORT compress2
        OF ((Bytef * dest, uLongf * destLen, const Bytef * source, uLong sourceLen, int level));
    /*
     * Compresses the source buffer into the destination buffer. The level
     * parameter has the same meaning as in deflateInit.  sourceLen is the byte
     * length of the source buffer. Upon entry, destLen is the total size of the
     * destination buffer, which must be at least 0.1% larger than sourceLen plus
     * 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
     * 
     * compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
     * memory, Z_BUF_ERROR if there was not enough room in the output buffer,
     * Z_STREAM_ERROR if the level parameter is invalid.
     */

    ZEXTERN int ZEXPORT uncompress OF ((Bytef * dest, uLongf * destLen, const Bytef * source, uLong sourceLen));
    /*
     * Decompresses the source buffer into the destination buffer.  sourceLen is
     * the byte length of the source buffer. Upon entry, destLen is the total
     * size of the destination buffer, which must be large enough to hold the
     * entire uncompressed data. (The size of the uncompressed data must have
     * been saved previously by the compressor and transmitted to the decompressor
     * by some mechanism outside the scope of this compression library.)
     * Upon exit, destLen is the actual size of the compressed buffer.
     * This function can be used to decompress a whole file at once if the
     * input file is mmap'ed.
     * 
     * uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
     * enough memory, Z_BUF_ERROR if there was not enough room in the output
     * buffer, or Z_DATA_ERROR if the input data was corrupted.
     */

    typedef voidp gzFile;

    ZEXTERN gzFile ZEXPORT gzopen OF ((const char *path, const char *mode));
    /*
     * Opens a gzip (.gz) file for reading or writing. The mode parameter
     * is as in fopen ("rb" or "wb") but can also include a compression level
     * ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
     * Huffman only compression as in "wb1h". (See the description
     * of deflateInit2 for more information about the strategy parameter.)
     * 
     * gzopen can be used to read a file which is not in gzip format; in this
     * case gzread will directly read from the file without decompression.
     * 
     * gzopen returns NULL if the file could not be opened or if there was
     * insufficient memory to allocate the (de)compression state; errno
     * can be checked to distinguish the two cases (if errno is zero, the
     * zlib error is Z_MEM_ERROR).  
     */

    ZEXTERN gzFile ZEXPORT gzdopen OF ((int fd, const char *mode));
    /*
     * gzdopen() associates a gzFile with the file descriptor fd.  File
     * descriptors are obtained from calls like open, dup, creat, pipe or
     * fileno (in the file has been previously opened with fopen).
     * The mode parameter is as in gzopen.
     * The next call of gzclose on the returned gzFile will also close the
     * file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
     * descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
     * gzdopen returns NULL if there was insufficient memory to allocate
     * the (de)compression state.
     */

    ZEXTERN int ZEXPORT gzsetparams OF ((gzFile file, int level, int strategy));
    /*
     * Dynamically update the compression level or strategy. See the description
     * of deflateInit2 for the meaning of these parameters.
     * gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
     * opened for writing.
     */

    ZEXTERN int ZEXPORT gzread OF ((gzFile file, voidp buf, unsigned len));
    /*
     * Reads the given number of uncompressed bytes from the compressed file.
     * If the input file was not in gzip format, gzread copies the given number
     * of bytes into the buffer.
     * gzread returns the number of uncompressed bytes actually read (0 for
     * end of file, -1 for error). 
     */

    ZEXTERN int ZEXPORT gzwrite OF ((gzFile file, const voidp buf, unsigned len));
    /*
     * Writes the given number of uncompressed bytes into the compressed file.
     * gzwrite returns the number of uncompressed bytes actually written
     * (0 in case of error).
     */

    ZEXTERN int ZEXPORTVA gzprintf OF ((gzFile file, const char *format, ...));
    /*
     * Converts, formats, and writes the args to the compressed file under
     * control of the format string, as in fprintf. gzprintf returns the number of
     * uncompressed bytes actually written (0 in case of error).
     */

    ZEXTERN int ZEXPORT gzputs OF ((gzFile file, const char *s));
    /*
     * Writes the given null-terminated string to the compressed file, excluding
     * the terminating null character.
     * gzputs returns the number of characters written, or -1 in case of error.
     */

    ZEXTERN char *ZEXPORT gzgets OF ((gzFile file, char *buf, int len));
    /*
     * Reads bytes from the compressed file until len-1 characters are read, or
     * a newline character is read and transferred to buf, or an end-of-file
     * condition is encountered.  The string is then terminated with a null
     * character.
     * gzgets returns buf, or Z_NULL in case of error.
     */

    ZEXTERN int ZEXPORT gzputc OF ((gzFile file, int c));
    /*
     * Writes c, converted to an unsigned char, into the compressed file.
     * gzputc returns the value that was written, or -1 in case of error.
     */

    ZEXTERN int ZEXPORT gzgetc OF ((gzFile file));
    /*
     * Reads one byte from the compressed file. gzgetc returns this byte
     * or -1 in case of end of file or error.
     */

    ZEXTERN int ZEXPORT gzflush OF ((gzFile file, int flush));
    /*
     * Flushes all pending output into the compressed file. The parameter
     * flush is as in the deflate() function. The return value is the zlib
     * error number (see function gzerror below). gzflush returns Z_OK if
     * the flush parameter is Z_FINISH and all output could be flushed.
     * gzflush should be called only when strictly necessary because it can
     * degrade compression.
     */

    ZEXTERN z_off_t ZEXPORT gzseek OF ((gzFile file, z_off_t offset, int whence));
    /*
     * Sets the starting position for the next gzread or gzwrite on the
     * given compressed file. The offset represents a number of bytes in the
     * uncompressed data stream. The whence parameter is defined as in lseek(2);
     * the value SEEK_END is not supported.
     * If the file is opened for reading, this function is emulated but can be
     * extremely slow. If the file is opened for writing, only forward seeks are
     * supported; gzseek then compresses a sequence of zeroes up to the new
     * starting position.
     * 
     * gzseek returns the resulting offset location as measured in bytes from
     * the beginning of the uncompressed stream, or -1 in case of error, in
     * particular if the file is opened for writing and the new starting position
     * would be before the current position.
     */

    ZEXTERN int ZEXPORT gzrewind OF ((gzFile file));
    /*
     * Rewinds the given file. This function is supported only for reading.
     * 
     * gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
     */

    ZEXTERN z_off_t ZEXPORT gztell OF ((gzFile file));
    /*
     * Returns the starting position for the next gzread or gzwrite on the
     * given compressed file. This position represents a number of bytes in the
     * uncompressed data stream.
     * 
     * gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
     */

    ZEXTERN int ZEXPORT gzeof OF ((gzFile file));
    /*
     * Returns 1 when EOF has previously been detected reading the given
     * input stream, otherwise zero.
     */

    ZEXTERN int ZEXPORT gzclose OF ((gzFile file));
    /*
     * Flushes all pending output if necessary, closes the compressed file
     * and deallocates all the (de)compression state. The return value is the zlib
     * error number (see function gzerror below).
     */

    ZEXTERN const char *ZEXPORT gzerror OF ((gzFile file, int *errnum));
    /*
     * Returns the error message for the last error which occurred on the
     * given compressed file. errnum is set to zlib error number. If an
     * error occurred in the file system and not in the compression library,
     * errnum is set to Z_ERRNO and the application may consult errno
     * to get the exact error code.
     */

    /*
     * checksum functions 
     */

    /*
     * These functions are not related to compression but are exported
     * anyway because they might be useful in applications using the
     * compression library.
     */

    ZEXTERN uLong ZEXPORT adler32 OF ((uLong adler, const Bytef * buf, uInt len));

    /*
     * Update a running Adler-32 checksum with the bytes buf[0..len-1] and
     * return the updated checksum. If buf is NULL, this function returns
     * the required initial value for the checksum.
     * An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
     * much faster. Usage example:
     * 
     * uLong adler = adler32(0L, Z_NULL, 0);
     * 
     * while (read_buffer(buffer, length) != EOF) {
     * adler = adler32(adler, buffer, length);
     * }
     * if (adler != original_adler) error();
     */

    ZEXTERN uLong ZEXPORT crc32 OF ((uLong crc, const Bytef * buf, uInt len));
    /*
     * Update a running crc with the bytes buf[0..len-1] and return the updated
     * crc. If buf is NULL, this function returns the required initial value
     * for the crc. Pre- and post-conditioning (one's complement) is performed
     * within this function so it shouldn't be done by the application.
     * Usage example:
     * 
     * uLong crc = crc32(0L, Z_NULL, 0);
     * 
     * while (read_buffer(buffer, length) != EOF) {
     * crc = crc32(crc, buffer, length);
     * }
     * if (crc != original_crc) error();
     */

    /*
     * various hacks, don't look :) 
     */

    /*
     * deflateInit and inflateInit are macros to allow checking the zlib version
     * * and the compiler's view of z_stream:
     */
    ZEXTERN int ZEXPORT deflateInit_ OF ((z_streamp strm, int level, const char *version, int stream_size));
    ZEXTERN int ZEXPORT inflateInit_ OF ((z_streamp strm, const char *version, int stream_size));
    ZEXTERN int ZEXPORT deflateInit2_
        OF ((z_streamp strm, int level, int method, int windowBits, int memLevel, int strategy, const char *version,
             int stream_size));
    ZEXTERN int ZEXPORT inflateInit2_ OF ((z_streamp strm, int windowBits, const char *version, int stream_size));
#  define deflateInit(strm, level) \
        deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
#  define inflateInit(strm) \
        inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
#  define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
        deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
                      (strategy),           ZLIB_VERSION, sizeof(z_stream))
#  define inflateInit2(strm, windowBits) \
        inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))

#  if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
    struct internal_state {
        int           dummy;
    };                                 /* hack for buggy compilers */
#  endif

    ZEXTERN const char *ZEXPORT zError OF ((int err));
    ZEXTERN int ZEXPORT inflateSyncPoint OF ((z_streamp z));
    ZEXTERN const uLongf *ZEXPORT get_crc_table OF ((void));

#  ifdef __cplusplus
}
#  endif
#endif                                 /* _ZLIB_H */
