/*
 * Copyright (c) 2008 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
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 */
/* 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

#ifdef __cplusplus
extern "C" {
#endif

#include "zconf.h"

#define ZLIB_VERSION "1.2.3"
#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.
 */

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: binary or text */
	uLong   adler;  /* adler32 value of the uncompressed data */
	uLong   reserved;/* reserved for future use */
} z_stream;

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 {
	int     text;   /* true if compressed data believed to be text */
	uLong   time;   /* modification time */
	int     xflags; /* extra flags (not used when writing a gzip file) */
	int     os;     /* operating system */
	Bytef   *extra; /* pointer to extra field or Z_NULL if none */
	uInt    extra_len;/* extra field length (valid if extra != Z_NULL) */
	uInt    extra_max;/* space at extra (only when reading header) */
	Bytef   *name;  /* pointer to zero-terminated file name or Z_NULL */
	uInt    name_max;/* space at name (only when reading header) */
	Bytef   *comment;/* pointer to zero-terminated comment or Z_NULL */
	uInt    comm_max;/* space at comment (only when reading header) */
	int     hcrc;   /* true if there was or will be a header crc */
	int     done;   /* true when done reading gzip header (not used
	                 *  when writing a gzip file) */
} 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 */

#define Z_NO_FLUSH      0
#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
/* 2 is a reserved value (in zlib 1.2.3, Z_PACKET_FLUSH was removed) */
#define Z_SYNC_FLUSH    3
#define Z_FULL_FLUSH    4
#define Z_FINISH        5
#define Z_BLOCK         6

/* Allowed flush values; see deflate() and inflate() 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_RLE                 3
#define Z_FIXED               4
#define Z_DEFAULT_STRATEGY    0
/* compression strategy; see deflateInit2() below for details */

#define Z_BINARY   0
#define Z_TEXT     1
#define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
#define Z_UNKNOWN  2
/* Possible values of the data_type field (though see inflate()) */

#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.
 *
 *   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.
 */


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 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.
 */


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.
 *
 *    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 255 (unknown).  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().
 */

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. 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.
 *
 *    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.
 */

#if XNU_KERNEL_PRIVATE

typedef int    (*z_input_func) (z_streamp strm, Bytef *buf, unsigned size);
typedef int    (*z_output_func)(z_streamp strm, Bytef *buf, unsigned size);

ZEXTERN int ZEXPORT deflateResetWithIO(z_streamp strm, z_input_func zinput, z_output_func zoutput);

#endif /* XNU_KERNEL_PRIVATE */

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 deflateTune OF((z_streamp strm,
    int good_length,
    int max_lazy,
    int nice_length,
    int max_chain));
/*
 *    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(), and
 *  returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
 */

ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
    uLong sourceLen));
/*
 *    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().
 */

ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
    int bits,
    int value));
/*
 *    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.
 *
 *     deflatePrime 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));
/*
 *     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 255, with no extra, name, or comment
 *  fields.  The gzip header is returned to the default state by deflateReset().
 *
 *     deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
 *  stream state was inconsistent.
 */

/*
 *  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.
 *
 *    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.)
 */

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 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 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 inflateCopy 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 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.
 *
 *    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 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).
 */

ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
    int bits,
    int value));
/*
 *    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.
 *
 *     inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
 *  stream state was inconsistent.
 */

ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
    gz_headerp head));
/*
 *     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
 *  structure to duplicate the header.  However if those fields are set to
 *  allocated memory, then the application will need to save those pointers
 *  elsewhere so that they can be eventually freed.
 *
 *     If inflateGetHeader is not used, then the header information is simply
 *  discarded.  The header is always checked for validity, including the header
 *  CRC if present.  inflateReset() will reset the process to discard the header
 *  information.  The application would need to call inflateGetHeader() again to
 *  retrieve the header from the next gzip stream.
 *
 *     inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
 *  stream state was inconsistent.
 */

/*
 *  ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
 *                                       unsigned char FAR *window));
 *
 *    Initialize the internal stream state for decompression using inflateBack()
 *  calls.  The fields zalloc, zfree and opaque in strm must be initialized
 *  before the call.  If zalloc and zfree are Z_NULL, then the default library-
 *  derived memory allocation routines are used.  windowBits is the base two
 *  logarithm of the window size, in the range 8..15.  window is a caller
 *  supplied buffer of that size.  Except for special applications where it is
 *  assured that deflate was used with small window sizes, windowBits must be 15
 *  and a 32K byte window must be supplied to be able to decompress general
 *  deflate streams.
 *
 *    See inflateBack() for the usage of these routines.
 *
 *    inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
 *  the paramaters are invalid, Z_MEM_ERROR if the internal state could not
 *  be allocated, or Z_VERSION_ERROR if the version of the library does not
 *  match the version of the header file.
 */

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

ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
    in_func in, void FAR *in_desc,
    out_func out, void FAR *out_desc));
/*
 *    inflateBack() does a raw inflate with a single call using a call-back
 *  interface for input and output.  This is more efficient than inflate() for
 *  file i/o applications in that it avoids copying between the output and the
 *  sliding window by simply making the window itself the output buffer.  This
 *  function trusts the application to not change the output buffer passed by
 *  the output function, at least until inflateBack() returns.
 *
 *    inflateBackInit() must be called first to allocate the internal state
 *  and to initialize the state with the user-provided window buffer.
 *  inflateBack() may then be used multiple times to inflate a complete, raw
 *  deflate stream with each call.  inflateBackEnd() is then called to free
 *  the allocated state.
 *
 *    A raw deflate stream is one with no zlib or gzip header or trailer.
 *  This routine would normally be used in a utility that reads zip or gzip
 *  files and writes out uncompressed files.  The utility would decode the
 *  header and process the trailer on its own, hence this routine expects
 *  only the raw deflate stream to decompress.  This is different from the
 *  normal behavior of inflate(), which expects either a zlib or gzip header and
 *  trailer around the deflate stream.
 *
 *    inflateBack() uses two subroutines supplied by the caller that are then
 *  called by inflateBack() for input and output.  inflateBack() calls those
 *  routines until it reads a complete deflate stream and writes out all of the
 *  uncompressed data, or until it encounters an error.  The function's
 *  parameters and return types are defined above in the in_func and out_func
 *  typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
 *  number of bytes of provided input, and a pointer to that input in buf.  If
 *  there is no input available, in() must return zero--buf is ignored in that
 *  case--and inflateBack() will return a buffer error.  inflateBack() will call
 *  out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
 *  should return zero on success, or non-zero on failure.  If out() returns
 *  non-zero, inflateBack() will return with an error.  Neither in() nor out()
 *  are permitted to change the contents of the window provided to
 *  inflateBackInit(), which is also the buffer that out() uses to write from.
 *  The length written by out() will be at most the window size.  Any non-zero
 *  amount of input may be provided by in().
 *
 *    For convenience, inflateBack() can be provided input on the first call by
 *  setting strm->next_in and strm->avail_in.  If that input is exhausted, then
 *  in() will be called.  Therefore strm->next_in must be initialized before
 *  calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
 *  immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
 *  must also be initialized, and then if strm->avail_in is not zero, input will
 *  initially be taken from strm->next_in[0 .. strm->avail_in - 1].
 *
 *    The in_desc and out_desc parameters of inflateBack() is passed as the
 *  first parameter of in() and out() respectively when they are called.  These
 *  descriptors can be optionally used to pass any information that the caller-
 *  supplied in() and out() functions need to do their job.
 *
 *    On return, inflateBack() will set strm->next_in and strm->avail_in to
 *  pass back any unused input that was provided by the last in() call.  The
 *  return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
 *  if in() or out() returned an error, Z_DATA_ERROR if there was a format
 *  error in the deflate stream (in which case strm->msg is set to indicate the
 *  nature of the error), or Z_STREAM_ERROR if the stream was not properly
 *  initialized.  In the case of Z_BUF_ERROR, an input or output error can be
 *  distinguished using strm->next_in which will be Z_NULL only if in() returned
 *  an error.  If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
 *  out() returning non-zero.  (in() will always be called before out(), so
 *  strm->next_in is assured to be defined if out() returns non-zero.)  Note
 *  that inflateBack() cannot return Z_OK.
 */

ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
/*
 *    All memory allocated by inflateBackInit() is freed.
 *
 *    inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
 *  state was inconsistent.
 */

ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
/* Return flags indicating compile-time options.
 *
 *   Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
 *    1.0: size of uInt
 *    3.2: size of uLong
 *    5.4: size of voidpf (pointer)
 *    7.6: size of z_off_t
 *
 *   Compiler, assembler, and debug options:
 *    8: DEBUG
 *    9: ASMV or ASMINF -- use ASM code
 *    10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
 *    11: 0 (reserved)
 *
 *   One-time table building (smaller code, but not thread-safe if true):
 *    12: BUILDFIXED -- build static block decoding tables when needed
 *    13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
 *    14,15: 0 (reserved)
 *
 *   Library content (indicates missing functionality):
 *    16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
 *                         deflate code when not needed)
 *    17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
 *                   and decode gzip streams (to avoid linking crc code)
 *    18-19: 0 (reserved)
 *
 *   Operation variations (changes in library functionality):
 *    20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
 *    21: FASTEST -- deflate algorithm with only one, lowest compression level
 *    22,23: 0 (reserved)
 *
 *   The sprintf variant used by gzprintf (zero is best):
 *    24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
 *    25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
 *    26: 0 = returns value, 1 = void -- 1 means inferred string length returned
 *
 *   Remainder:
 *    27-31: 0 (reserved)
 */


/* 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 the value returned
 *  by compressBound(sourceLen). 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 the value returned by
 *  compressBound(sourceLen). 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 uLong ZEXPORT compressBound OF((uLong sourceLen));
/*
 *    compressBound() returns an upper bound on the compressed size after
 *  compress() or compress2() on sourceLen bytes.  It would be used before
 *  a compress() or compress2() call to allocate the destination buffer.
 */

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 or incomplete.
 */

#if XNU_KERNEL_PRIVATE

ZEXTERN uLong zlib_deflate_memory_size(int wbits, int memlevel);

#endif /* XNU_KERNEL_PRIVATE */

#if !KERNEL

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", or 'R' for run-length encoding
 *  as in "wb1R". (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,
    voidpc 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).  The number of
 *  uncompressed bytes written is limited to 4095. The caller should assure that
 *  this limit is not exceeded. If it is exceeded, then gzprintf() will return
 *  return an error (0) with nothing written. In this case, there may also be a
 *  buffer overflow with unpredictable consequences, which is possible only if
 *  zlib was compiled with the insecure functions sprintf() or vsprintf()
 *  because the secure snprintf() or vsnprintf() functions were not available.
 */

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    gzungetc OF((int c, gzFile file));
/*
 *     Push one character back onto the stream to be read again later.
 *  Only one character of push-back is allowed.  gzungetc() returns the
 *  character pushed, or -1 on failure.  gzungetc() will fail if a
 *  character has been pushed but not read yet, or if c is -1. The pushed
 *  character will be discarded if the stream is repositioned with gzseek()
 *  or gzrewind().
 */

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 gzdirect OF((gzFile file));
/*
 *    Returns 1 if file is being read directly without decompression, 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.
 */

ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
/*
 *    Clears the error and end-of-file flags for file. This is analogous to the
 *  clearerr() function in stdio. This is useful for continuing to read a gzip
 *  file that is being written concurrently.
 */

#endif /* KERNEL */

/* 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 adler32_combine OF((uLong adler1, uLong adler2,
    z_off_t len2));
/*
 *    Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
 *  and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
 *  each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
 *  seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
 */

ZEXTERN uLong ZEXPORT z_crc32   OF((uLong crc, const Bytef *buf, uInt len));
/*
 *    Update a running CRC-32 with the bytes buf[0..len-1] and return the
 *  updated CRC-32. If buf is NULL, this function returns the required initial
 *  value for the 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();
 */

ZEXTERN uLong ZEXPORT z_crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));

/*
 *    Combine two CRC-32 check values into one.  For two sequences of bytes,
 *  seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
 *  calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
 *  check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
 *  len2.
 */


/* 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));
ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
    unsigned char FAR *window,
    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))
#define inflateBackInit(strm, windowBits, window) \
	inflateBackInit_((strm), (windowBits), (window), \
	ZLIB_VERSION, sizeof(z_stream))


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

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

#ifdef __cplusplus
}
#endif

#endif /* ZLIB_H */
