170c83c0peter/* zlib.h -- interface of the 'zlib' general purpose compression library
209e63a0delphij  version 1.2.11, January 15th, 2017
4abe96eddelphij  Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
670c83c0peter  This software is provided 'as-is', without any express or implied
770c83c0peter  warranty.  In no event will the authors be held liable for any damages
870c83c0peter  arising from the use of this software.
1070c83c0peter  Permission is granted to anyone to use this software for any purpose,
1170c83c0peter  including commercial applications, and to alter it and redistribute it
1270c83c0peter  freely, subject to the following restrictions:
1470c83c0peter  1. The origin of this software must not be misrepresented; you must not
1570c83c0peter     claim that you wrote the original software. If you use this software
1670c83c0peter     in a product, an acknowledgment in the product documentation would be
1770c83c0peter     appreciated but is not required.
1870c83c0peter  2. Altered source versions must be plainly marked as such, and must not be
1970c83c0peter     misrepresented as being the original software.
2070c83c0peter  3. This notice may not be removed or altered from any source distribution.
2270c83c0peter  Jean-loup Gailly        Mark Adler
239f86c0bsteve  jloup@gzip.org          madler@alumni.caltech.edu
2670c83c0peter  The data format used by the zlib library is described by RFCs (Request for
27abe1867delphij  Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
28abe1867delphij  (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
31439ed8dtjr#ifndef ZLIB_H
32439ed8dtjr#define ZLIB_H
34b66130epeter#include "zconf.h"
3670c83c0peter#ifdef __cplusplus
3770c83c0peterextern "C" {
4009e63a0delphij#define ZLIB_VERSION "1.2.11"
4109e63a0delphij#define ZLIB_VERNUM 0x12b0
42354ebf4delphij#define ZLIB_VER_MAJOR 1
43354ebf4delphij#define ZLIB_VER_MINOR 2
4409e63a0delphij#define ZLIB_VER_REVISION 11
454fabf72delphij#define ZLIB_VER_SUBREVISION 0
48354ebf4delphij    The 'zlib' compression library provides in-memory compression and
49354ebf4delphij  decompression functions, including integrity checks of the uncompressed data.
50354ebf4delphij  This version of the library supports only one compression method (deflation)
51354ebf4delphij  but other algorithms will be added later and will have the same stream
52354ebf4delphij  interface.
54354ebf4delphij    Compression can be done in a single step if the buffers are large enough,
55354ebf4delphij  or can be done by repeated calls of the compression function.  In the latter
56354ebf4delphij  case, the application must provide more input and/or consume the output
5770c83c0peter  (providing more output space) before each call.
59354ebf4delphij    The compressed data format used by default by the in-memory functions is
60dcdd797kientzle  the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
61dcdd797kientzle  around a deflate stream, which is itself documented in RFC 1951.
63354ebf4delphij    The library also supports reading and writing files in gzip (.gz) format
64439ed8dtjr  with an interface similar to that of stdio using the functions that start
65439ed8dtjr  with "gz".  The gzip format is different from the zlib format.  gzip is a
66439ed8dtjr  gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
68abe96eddelphij    This library can optionally read and write gzip and raw deflate streams in
69abe96eddelphij  memory as well.
71354ebf4delphij    The zlib format was designed to be compact and fast for use in memory
72439ed8dtjr  and on communications channels.  The gzip format was designed for single-
73439ed8dtjr  file compression on file systems, has a larger header than zlib to maintain
74439ed8dtjr  directory information, and uses a different, slower check method than zlib.
76354ebf4delphij    The library does not install any signal handler.  The decoder checks
77354ebf4delphij  the consistency of the compressed data, so the library should never crash
78abe96eddelphij  even in the case of corrupted input.
8170c83c0petertypedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
8270c83c0petertypedef void   (*free_func)  OF((voidpf opaque, voidpf address));
8470c83c0peterstruct internal_state;
8670c83c0petertypedef struct z_stream_s {
87abe1867delphij    z_const Bytef *next_in;     /* next input byte */
8870c83c0peter    uInt     avail_in;  /* number of bytes available at next_in */
89abe1867delphij    uLong    total_in;  /* total number of input bytes read so far */
91abe96eddelphij    Bytef    *next_out; /* next output byte will go here */
9270c83c0peter    uInt     avail_out; /* remaining free space at next_out */
93abe1867delphij    uLong    total_out; /* total number of bytes output so far */
95abe1867delphij    z_const char *msg;  /* last error message, NULL if no error */
9670c83c0peter    struct internal_state FAR *state; /* not visible by applications */
9870c83c0peter    alloc_func zalloc;  /* used to allocate the internal state */
9970c83c0peter    free_func  zfree;   /* used to free the internal state */
10070c83c0peter    voidpf     opaque;  /* private data object passed to zalloc and zfree */
102abe96eddelphij    int     data_type;  /* best guess about the data type: binary or text
103abe96eddelphij                           for deflate, or the decoding state for inflate */
104abe96eddelphij    uLong   adler;      /* Adler-32 or CRC-32 value of the uncompressed data */
10570c83c0peter    uLong   reserved;   /* reserved for future use */
10670c83c0peter} z_stream;
10870c83c0petertypedef z_stream FAR *z_streamp;
111caf24dddes     gzip header information passed to and from zlib routines.  See RFC 1952
112caf24dddes  for more details on the meanings of these fields.
114caf24dddestypedef struct gz_header_s {
115caf24dddes    int     text;       /* true if compressed data believed to be text */
116caf24dddes    uLong   time;       /* modification time */
117caf24dddes    int     xflags;     /* extra flags (not used when writing a gzip file) */
118caf24dddes    int     os;         /* operating system */
119caf24dddes    Bytef   *extra;     /* pointer to extra field or Z_NULL if none */
120caf24dddes    uInt    extra_len;  /* extra field length (valid if extra != Z_NULL) */
121caf24dddes    uInt    extra_max;  /* space at extra (only when reading header) */
122caf24dddes    Bytef   *name;      /* pointer to zero-terminated file name or Z_NULL */
123caf24dddes    uInt    name_max;   /* space at name (only when reading header) */
124caf24dddes    Bytef   *comment;   /* pointer to zero-terminated comment or Z_NULL */
125caf24dddes    uInt    comm_max;   /* space at comment (only when reading header) */
126caf24dddes    int     hcrc;       /* true if there was or will be a header crc */
127caf24dddes    int     done;       /* true when done reading gzip header (not used
128caf24dddes                           when writing a gzip file) */
129caf24dddes} gz_header;
131caf24dddestypedef gz_header FAR *gz_headerp;
134354ebf4delphij     The application must update next_in and avail_in when avail_in has dropped
135354ebf4delphij   to zero.  It must update next_out and avail_out when avail_out has dropped
136354ebf4delphij   to zero.  The application must initialize zalloc, zfree and opaque before
137354ebf4delphij   calling the init function.  All other fields are set by the compression
138354ebf4delphij   library and must not be updated by the application.
140354ebf4delphij     The opaque value provided by the application will be passed as the first
141354ebf4delphij   parameter for calls of zalloc and zfree.  This can be useful for custom
142354ebf4delphij   memory management.  The compression library attaches no meaning to the
14370c83c0peter   opaque value.
145354ebf4delphij     zalloc must return Z_NULL if there is not enough memory for the object.
1469f86c0bsteve   If zlib is used in a multi-threaded application, zalloc and zfree must be
147abe96eddelphij   thread safe.  In that case, zlib is thread-safe.  When zalloc and zfree are
148abe96eddelphij   Z_NULL on entry to the initialization function, they are set to internal
149abe96eddelphij   routines that use the standard library functions malloc() and free().
151354ebf4delphij     On 16-bit systems, the functions zalloc and zfree must be able to allocate
152354ebf4delphij   exactly 65536 bytes, but will not be required to allocate more than this if
153354ebf4delphij   the symbol MAXSEG_64K is defined (see zconf.h).  WARNING: On MSDOS, pointers
154354ebf4delphij   returned by zalloc for objects of exactly 65536 bytes *must* have their
155354ebf4delphij   offset normalized to zero.  The default allocation function provided by this
156354ebf4delphij   library ensures this (see zutil.c).  To reduce memory requirements and avoid
157354ebf4delphij   any allocation of 64K objects, at the expense of compression ratio, compile
158354ebf4delphij   the library with -DMAX_WBITS=14 (see zconf.h).
160354ebf4delphij     The fields total_in and total_out can be used for statistics or progress
161354ebf4delphij   reports.  After compression, total_in holds the total size of the
162abe96eddelphij   uncompressed data and may be saved for use by the decompressor (particularly
163354ebf4delphij   if the decompressor wants to decompress everything in a single step).
16670c83c0peter                        /* constants */
16870c83c0peter#define Z_NO_FLUSH      0
169354ebf4delphij#define Z_PARTIAL_FLUSH 1
17070c83c0peter#define Z_SYNC_FLUSH    2
17170c83c0peter#define Z_FULL_FLUSH    3
17270c83c0peter#define Z_FINISH        4
173439ed8dtjr#define Z_BLOCK         5
174354ebf4delphij#define Z_TREES         6
175439ed8dtjr/* Allowed flush values; see deflate() and inflate() below for details */
17770c83c0peter#define Z_OK            0
17870c83c0peter#define Z_STREAM_END    1
17970c83c0peter#define Z_NEED_DICT     2
18070c83c0peter#define Z_ERRNO        (-1)
18170c83c0peter#define Z_STREAM_ERROR (-2)
18270c83c0peter#define Z_DATA_ERROR   (-3)
18370c83c0peter#define Z_MEM_ERROR    (-4)
18470c83c0peter#define Z_BUF_ERROR    (-5)
18570c83c0peter#define Z_VERSION_ERROR (-6)
186354ebf4delphij/* Return codes for the compression/decompression functions. Negative values
187354ebf4delphij * are errors, positive values are used for special but normal events.
18870c83c0peter */
19070c83c0peter#define Z_NO_COMPRESSION         0
19170c83c0peter#define Z_BEST_SPEED             1
19270c83c0peter#define Z_BEST_COMPRESSION       9
19370c83c0peter#define Z_DEFAULT_COMPRESSION  (-1)
19470c83c0peter/* compression levels */
19670c83c0peter#define Z_FILTERED            1
19770c83c0peter#define Z_HUFFMAN_ONLY        2
198439ed8dtjr#define Z_RLE                 3
199caf24dddes#define Z_FIXED               4
20070c83c0peter#define Z_DEFAULT_STRATEGY    0
20170c83c0peter/* compression strategy; see deflateInit2() below for details */
20370c83c0peter#define Z_BINARY   0
204caf24dddes#define Z_TEXT     1
205caf24dddes#define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
20670c83c0peter#define Z_UNKNOWN  2
207abe96eddelphij/* Possible values of the data_type field for deflate() */
20970c83c0peter#define Z_DEFLATED   8
21070c83c0peter/* The deflate compression method (the only one supported in this version) */
21270c83c0peter#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
21470c83c0peter#define zlib_version zlibVersion()
21570c83c0peter/* for compatibility with versions < 1.0.2 */
21870c83c0peter                        /* basic functions */
220b66130epeterZEXTERN const char * ZEXPORT zlibVersion OF((void));
22170c83c0peter/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
222354ebf4delphij   If the first character differs, the library code actually used is not
223354ebf4delphij   compatible with the zlib.h header file used by the application.  This check
224354ebf4delphij   is automatically made by deflateInit and inflateInit.
22570c83c0peter */
228b66130epeterZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
230354ebf4delphij     Initializes the internal stream state for compression.  The fields
231354ebf4delphij   zalloc, zfree and opaque must be initialized before by the caller.  If
232354ebf4delphij   zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
233354ebf4delphij   allocation functions.
23570c83c0peter     The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
236354ebf4delphij   1 gives best speed, 9 gives best compression, 0 gives no compression at all
237354ebf4delphij   (the input data is simply copied a block at a time).  Z_DEFAULT_COMPRESSION
238354ebf4delphij   requests a default compromise between speed and compression (currently
239354ebf4delphij   equivalent to level 6).
241354ebf4delphij     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
242354ebf4delphij   memory, Z_STREAM_ERROR if level is not a valid compression level, or
24370c83c0peter   Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
244354ebf4delphij   with the version assumed by the caller (ZLIB_VERSION).  msg is set to null
245354ebf4delphij   if there is no error message.  deflateInit does not perform any compression:
246354ebf4delphij   this will be done by deflate().
250b66130epeterZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
2529f86c0bsteve    deflate compresses as much data as possible, and stops when the input
253354ebf4delphij  buffer becomes empty or the output buffer becomes full.  It may introduce
254354ebf4delphij  some output latency (reading input without producing any output) except when
2559f86c0bsteve  forced to flush.
257354ebf4delphij    The detailed semantics are as follows.  deflate performs one or both of the
2589f86c0bsteve  following actions:
26070c83c0peter  - Compress more input starting at next_in and update next_in and avail_in
261354ebf4delphij    accordingly.  If not all input can be processed (because there is not
26270c83c0peter    enough room in the output buffer), next_in and avail_in are updated and
26370c83c0peter    processing will resume at this point for the next call of deflate().
265abe96eddelphij  - Generate more output starting at next_out and update next_out and avail_out
266354ebf4delphij    accordingly.  This action is forced if the parameter flush is non zero.
26770c83c0peter    Forcing flush frequently degrades the compression ratio, so this parameter
268abe96eddelphij    should be set only when necessary.  Some output may be provided even if
269abe96eddelphij    flush is zero.
271354ebf4delphij    Before the call of deflate(), the application should ensure that at least
272354ebf4delphij  one of the actions is possible, by providing more input and/or consuming more
273354ebf4delphij  output, and updating avail_in or avail_out accordingly; avail_out should
274354ebf4delphij  never be zero before the call.  The application can consume the compressed
275354ebf4delphij  output when it wants, for example when the output buffer is full (avail_out
276354ebf4delphij  == 0), or after each call of deflate().  If deflate returns Z_OK and with
277354ebf4delphij  zero avail_out, it must be called again after making room in the output
278abe96eddelphij  buffer because there might be more output pending. See deflatePending(),
279abe96eddelphij  which can be used if desired to determine whether or not there is more ouput
280abe96eddelphij  in that case.
282caf24dddes    Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
283354ebf4delphij  decide how much data to accumulate before producing output, in order to
284caf24dddes  maximize compression.
2869f86c0bsteve    If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
2879f86c0bsteve  flushed to the output buffer and the output is aligned on a byte boundary, so
288354ebf4delphij  that the decompressor can get all input data available so far.  (In
289354ebf4delphij  particular avail_in is zero after the call if enough output space has been
290354ebf4delphij  provided before the call.) Flushing may degrade compression for some
291354ebf4delphij  compression algorithms and so it should be used only when necessary.  This
292354ebf4delphij  completes the current deflate block and follows it with an empty stored block
293354ebf4delphij  that is three bits plus filler bits to the next byte, followed by four bytes
294354ebf4delphij  (00 00 ff ff).
296354ebf4delphij    If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
297354ebf4delphij  output buffer, but the output is not aligned to a byte boundary.  All of the
298354ebf4delphij  input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
299354ebf4delphij  This completes the current deflate block and follows it with an empty fixed
300354ebf4delphij  codes block that is 10 bits long.  This assures that enough bytes are output
301abe96eddelphij  in order for the decompressor to finish the block before the empty fixed
302abe96eddelphij  codes block.
304354ebf4delphij    If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
305354ebf4delphij  for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
306354ebf4delphij  seven bits of the current block are held to be written as the next byte after
307354ebf4delphij  the next deflate block is completed.  In this case, the decompressor may not
308354ebf4delphij  be provided enough bits at this point in order to complete decompression of
309354ebf4delphij  the data provided so far to the compressor.  It may need to wait for the next
310354ebf4delphij  block to be emitted.  This is for advanced applications that need to control
311354ebf4delphij  the emission of deflate blocks.
3139f86c0bsteve    If flush is set to Z_FULL_FLUSH, all output is flushed as with
3149f86c0bsteve  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
3159f86c0bsteve  restart from this point if previous compressed data has been damaged or if
316354ebf4delphij  random access is desired.  Using Z_FULL_FLUSH too often can seriously degrade
317caf24dddes  compression.
3199f86c0bsteve    If deflate returns with avail_out == 0, this function must be called again
3209f86c0bsteve  with the same value of the flush parameter and more output space (updated
3219f86c0bsteve  avail_out), until the flush is complete (deflate returns with non-zero
322354ebf4delphij  avail_out).  In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
323439ed8dtjr  avail_out is greater than six to avoid repeated flush markers due to
324439ed8dtjr  avail_out == 0 on return.
32670c83c0peter    If the parameter flush is set to Z_FINISH, pending input is processed,
327354ebf4delphij  pending output is flushed and deflate returns with Z_STREAM_END if there was
328abe96eddelphij  enough output space.  If deflate returns with Z_OK or Z_BUF_ERROR, this
329abe96eddelphij  function must be called again with Z_FINISH and more output space (updated
330abe96eddelphij  avail_out) but no more input data, until it returns with Z_STREAM_END or an
331abe96eddelphij  error.  After deflate has returned Z_STREAM_END, the only possible operations
332abe96eddelphij  on the stream are deflateReset or deflateEnd.
334abe96eddelphij    Z_FINISH can be used in the first deflate call after deflateInit if all the
335abe96eddelphij  compression is to be done in a single step.  In order to complete in one
336abe96eddelphij  call, avail_out must be at least the value returned by deflateBound (see
337abe96eddelphij  below).  Then deflate is guaranteed to return Z_STREAM_END.  If not enough
338abe96eddelphij  output space is provided, deflate will not return Z_STREAM_END, and it must
339abe96eddelphij  be called again as described above.
341abe96eddelphij    deflate() sets strm->adler to the Adler-32 checksum of all input read
342abe96eddelphij  so far (that is, total_in bytes).  If a gzip stream is being generated, then
343abe96eddelphij  strm->adler will be the CRC-32 checksum of the input read so far.  (See
344abe96eddelphij  deflateInit2 below.)
346caf24dddes    deflate() may update strm->data_type if it can make a good guess about
347abe96eddelphij  the input data type (Z_BINARY or Z_TEXT).  If in doubt, the data is
348abe96eddelphij  considered binary.  This field is only for information purposes and does not
349abe96eddelphij  affect the compression algorithm in any manner.
35170c83c0peter    deflate() returns Z_OK if some progress has been made (more input
35270c83c0peter  processed or more output produced), Z_STREAM_END if all input has been
35370c83c0peter  consumed and all output has been produced (only when flush is set to
35470c83c0peter  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
355abe96eddelphij  if next_in or next_out was Z_NULL or the state was inadvertently written over
356abe96eddelphij  by the application), or Z_BUF_ERROR if no progress is possible (for example
357abe96eddelphij  avail_in or avail_out was zero).  Note that Z_BUF_ERROR is not fatal, and
358abe96eddelphij  deflate() can be called again with more input and more output space to
359abe96eddelphij  continue compressing.
363b66130epeterZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
36570c83c0peter     All dynamically allocated data structures for this stream are freed.
366354ebf4delphij   This function discards any unprocessed input and does not flush any pending
367354ebf4delphij   output.
36970c83c0peter     deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
37070c83c0peter   stream state was inconsistent, Z_DATA_ERROR if the stream was freed
371354ebf4delphij   prematurely (some input or output was discarded).  In the error case, msg
372354ebf4delphij   may be set but then points to a static string (which must not be
37370c83c0peter   deallocated).
378b66130epeterZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
380354ebf4delphij     Initializes the internal stream state for decompression.  The fields
3819f86c0bsteve   next_in, avail_in, zalloc, zfree and opaque must be initialized before by
382abe96eddelphij   the caller.  In the current version of inflate, the provided input is not
383abe96eddelphij   read or consumed.  The allocation of a sliding window will be deferred to
384abe96eddelphij   the first call of inflate (if the decompression does not complete on the
385abe96eddelphij   first call).  If zalloc and zfree are set to Z_NULL, inflateInit updates
386abe96eddelphij   them to use default allocation functions.
3889f86c0bsteve     inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
3899f86c0bsteve   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
390354ebf4delphij   version assumed by the caller, or Z_STREAM_ERROR if the parameters are
391354ebf4delphij   invalid, such as a null pointer to the structure.  msg is set to null if
392abe96eddelphij   there is no error message.  inflateInit does not perform any decompression.
393abe96eddelphij   Actual decompression will be done by inflate().  So next_in, and avail_in,
394abe96eddelphij   next_out, and avail_out are unused and unchanged.  The current
395abe96eddelphij   implementation of inflateInit() does not process any header information --
396abe96eddelphij   that is deferred until inflate() is called.
400b66130epeterZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
4029f86c0bsteve    inflate decompresses as much data as possible, and stops when the input
403354ebf4delphij  buffer becomes empty or the output buffer becomes full.  It may introduce
404439ed8dtjr  some output latency (reading input without producing any output) except when
405439ed8dtjr  forced to flush.
407354ebf4delphij  The detailed semantics are as follows.  inflate performs one or both of the
4089f86c0bsteve  following actions:
41070c83c0peter  - Decompress more input starting at next_in and update next_in and avail_in
411354ebf4delphij    accordingly.  If not all input can be processed (because there is not
412abe96eddelphij    enough room in the output buffer), then next_in and avail_in are updated
413abe96eddelphij    accordingly, and processing will resume at this point for the next call of
414abe96eddelphij    inflate().
416abe96eddelphij  - Generate more output starting at next_out and update next_out and avail_out
417354ebf4delphij    accordingly.  inflate() provides as much output as possible, until there is
418354ebf4delphij    no more input data or no more space in the output buffer (see below about
419354ebf4delphij    the flush parameter).
421354ebf4delphij    Before the call of inflate(), the application should ensure that at least
422354ebf4delphij  one of the actions is possible, by providing more input and/or consuming more
423abe96eddelphij  output, and updating the next_* and avail_* values accordingly.  If the
424abe96eddelphij  caller of inflate() does not provide both available input and available
425abe96eddelphij  output space, it is possible that there will be no progress made.  The
426354ebf4delphij  application can consume the uncompressed output when it wants, for example
427354ebf4delphij  when the output buffer is full (avail_out == 0), or after each call of
428354ebf4delphij  inflate().  If inflate returns Z_OK and with zero avail_out, it must be
429354ebf4delphij  called again after making room in the output buffer because there might be
430354ebf4delphij  more output pending.
432354ebf4delphij    The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
433354ebf4delphij  Z_BLOCK, or Z_TREES.  Z_SYNC_FLUSH requests that inflate() flush as much
434354ebf4delphij  output as possible to the output buffer.  Z_BLOCK requests that inflate()
435354ebf4delphij  stop if and when it gets to the next deflate block boundary.  When decoding
436354ebf4delphij  the zlib or gzip format, this will cause inflate() to return immediately
437354ebf4delphij  after the header and before the first block.  When doing a raw inflate,
438354ebf4delphij  inflate() will go ahead and process the first block, and will return when it
439354ebf4delphij  gets to the end of that block, or when it runs out of data.
441439ed8dtjr    The Z_BLOCK option assists in appending to or combining deflate streams.
442abe96eddelphij  To assist in this, on return inflate() always sets strm->data_type to the
443354ebf4delphij  number of unused bits in the last byte taken from strm->next_in, plus 64 if
444354ebf4delphij  inflate() is currently decoding the last block in the deflate stream, plus
445354ebf4delphij  128 if inflate() returned immediately after decoding an end-of-block code or
446354ebf4delphij  decoding the complete header up to just before the first byte of the deflate
447354ebf4delphij  stream.  The end-of-block will not be indicated until all of the uncompressed
448354ebf4delphij  data from that block has been written to strm->next_out.  The number of
449354ebf4delphij  unused bits may in general be greater than seven, except when bit 7 of
450354ebf4delphij  data_type is set, in which case the number of unused bits will be less than
451354ebf4delphij  eight.  data_type is set as noted here every time inflate() returns for all
452354ebf4delphij  flush options, and so can be used to determine the amount of currently
453354ebf4delphij  consumed input in bits.
455354ebf4delphij    The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
456354ebf4delphij  end of each deflate block header is reached, before any actual data in that
457354ebf4delphij  block is decoded.  This allows the caller to determine the length of the
458354ebf4delphij  deflate block header for later use in random access within a deflate block.
459354ebf4delphij  256 is added to the value of strm->data_type when inflate() returns
460354ebf4delphij  immediately after reaching the end of the deflate block header.
46270c83c0peter    inflate() should normally be called until it returns Z_STREAM_END or an
463354ebf4delphij  error.  However if all decompression is to be performed in a single step (a
464354ebf4delphij  single call of inflate), the parameter flush should be set to Z_FINISH.  In
465354ebf4delphij  this case all pending input is processed and all pending output is flushed;
4665ecec51delphij  avail_out must be large enough to hold all of the uncompressed data for the
4675ecec51delphij  operation to complete.  (The size of the uncompressed data may have been
468abe96eddelphij  saved by the compressor for this purpose.)  The use of Z_FINISH is not
4695ecec51delphij  required to perform an inflation in one step.  However it may be used to
4705ecec51delphij  inform inflate that a faster approach can be used for the single inflate()
4715ecec51delphij  call.  Z_FINISH also informs inflate to not maintain a sliding window if the
4725ecec51delphij  stream completes, which reduces inflate's memory footprint.  If the stream
4735ecec51delphij  does not complete, either because not all of the stream is provided or not
4745ecec51delphij  enough output space is provided, then a sliding window will be allocated and
4755ecec51delphij  inflate() can be called again to continue the operation as if Z_NO_FLUSH had
4765ecec51delphij  been used.
478439ed8dtjr     In this implementation, inflate() always flushes as much output as
479439ed8dtjr  possible to the output buffer, and always uses the faster approach on the
480abe1867delphij  first call.  So the effects of the flush parameter in this implementation are
481abe1867delphij  on the return value of inflate() as noted below, when inflate() returns early
482abe1867delphij  when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
483abe1867delphij  memory for a sliding window when Z_FINISH is used.
485439ed8dtjr     If a preset dictionary is needed after this call (see inflateSetDictionary
486abe1867delphij  below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
487439ed8dtjr  chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
488abe1867delphij  strm->adler to the Adler-32 checksum of all output produced so far (that is,
489439ed8dtjr  total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
490abe96eddelphij  below.  At the end of the stream, inflate() checks that its computed Adler-32
491439ed8dtjr  checksum is equal to that saved by the compressor and returns Z_STREAM_END
492439ed8dtjr  only if the checksum is correct.
494354ebf4delphij    inflate() can decompress and check either zlib-wrapped or gzip-wrapped
495354ebf4delphij  deflate data.  The header type is detected automatically, if requested when
496354ebf4delphij  initializing with inflateInit2().  Any information contained in the gzip
497abe96eddelphij  header is not retained unless inflateGetHeader() is used.  When processing
498abe1867delphij  gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
499abe96eddelphij  produced so far.  The CRC-32 is checked against the gzip trailer, as is the
500abe96eddelphij  uncompressed length, modulo 2^32.
5029f86c0bsteve    inflate() returns Z_OK if some progress has been made (more input processed
5039f86c0bsteve  or more output produced), Z_STREAM_END if the end of the compressed data has
5049f86c0bsteve  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
5059f86c0bsteve  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
506439ed8dtjr  corrupted (input stream not conforming to the zlib format or incorrect check
507abe96eddelphij  value, in which case strm->msg points to a string with a more specific
508abe96eddelphij  error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
509abe96eddelphij  next_in or next_out was Z_NULL, or the state was inadvertently written over
510abe96eddelphij  by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
511abe96eddelphij  if no progress was possible or if there was not enough room in the output
512abe96eddelphij  buffer when Z_FINISH is used.  Note that Z_BUF_ERROR is not fatal, and
513439ed8dtjr  inflate() can be called again with more input and more output space to
514354ebf4delphij  continue decompressing.  If Z_DATA_ERROR is returned, the application may
515354ebf4delphij  then call inflateSync() to look for a good compression block if a partial
516abe96eddelphij  recovery of the data is to be attempted.
520b66130epeterZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
52270c83c0peter     All dynamically allocated data structures for this stream are freed.
523354ebf4delphij   This function discards any unprocessed input and does not flush any pending
524354ebf4delphij   output.
526abe96eddelphij     inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
527abe96eddelphij   was inconsistent.
53170c83c0peter                        /* Advanced functions */
53470c83c0peter    The following functions are needed only in some special applications.
538b66130epeterZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
539b66130epeter                                     int  level,
540b66130epeter                                     int  method,
541b66130epeter                                     int  windowBits,
542b66130epeter                                     int  memLevel,
543b66130epeter                                     int  strategy));
545354ebf4delphij     This is another version of deflateInit with more compression options.  The
546354ebf4delphij   fields next_in, zalloc, zfree and opaque must be initialized before by the
547354ebf4delphij   caller.
549354ebf4delphij     The method parameter is the compression method.  It must be Z_DEFLATED in
5509f86c0bsteve   this version of the library.
55270c83c0peter     The windowBits parameter is the base two logarithm of the window size
553354ebf4delphij   (the size of the history buffer).  It should be in the range 8..15 for this
554354ebf4delphij   version of the library.  Larger values of this parameter result in better
555354ebf4delphij   compression at the expense of memory usage.  The default value is 15 if
5569f86c0bsteve   deflateInit is used instead.
558abe96eddelphij     For the current implementation of deflate(), a windowBits value of 8 (a
559abe96eddelphij   window size of 256 bytes) is not supported.  As a result, a request for 8
560abe96eddelphij   will result in 9 (a 512-byte window).  In that case, providing 8 to
561abe96eddelphij   inflateInit2() will result in an error when the zlib header with 9 is
562abe96eddelphij   checked against the initialization of inflate().  The remedy is to not use 8
563abe96eddelphij   with deflateInit2() with this initialization, or at least in that case use 9
564abe96eddelphij   with inflateInit2().
566354ebf4delphij     windowBits can also be -8..-15 for raw deflate.  In this case, -windowBits
567354ebf4delphij   determines the window size.  deflate() will then generate raw deflate data
568abe96eddelphij   with no zlib header or trailer, and will not compute a check value.
570354ebf4delphij     windowBits can also be greater than 15 for optional gzip encoding.  Add
571439ed8dtjr   16 to windowBits to write a simple gzip header and trailer around the
572354ebf4delphij   compressed data instead of a zlib wrapper.  The gzip header will have no
573354ebf4delphij   file name, no extra data, no comment, no modification time (set to zero), no
574abe96eddelphij   header crc, and the operating system will be set to the appropriate value,
575abe96eddelphij   if the operating system was determined at compile time.  If a gzip stream is
576abe96eddelphij   being written, strm->adler is a CRC-32 instead of an Adler-32.
578abe96eddelphij     For raw deflate or gzip encoding, a request for a 256-byte window is
579abe96eddelphij   rejected as invalid, since only the zlib header provides a means of
580abe96eddelphij   transmitting the window size to the decompressor.
58270c83c0peter     The memLevel parameter specifies how much memory should be allocated
583354ebf4delphij   for the internal compression state.  memLevel=1 uses minimum memory but is
584354ebf4delphij   slow and reduces compression ratio; memLevel=9 uses maximum memory for
585354ebf4delphij   optimal speed.  The default value is 8.  See zconf.h for total memory usage
586354ebf4delphij   as a function of windowBits and memLevel.
588354ebf4delphij     The strategy parameter is used to tune the compression algorithm.  Use the
58970c83c0peter   value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
590439ed8dtjr   filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
591439ed8dtjr   string match), or Z_RLE to limit match distances to one (run-length
592354ebf4delphij   encoding).  Filtered data consists mostly of small values with a somewhat
593354ebf4delphij   random distribution.  In this case, the compression algorithm is tuned to
594354ebf4delphij   compress them better.  The effect of Z_FILTERED is to force more Huffman
595439ed8dtjr   coding and less string matching; it is somewhat intermediate between
596354ebf4delphij   Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY.  Z_RLE is designed to be almost as
597354ebf4delphij   fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data.  The
598354ebf4delphij   strategy parameter only affects the compression ratio but not the
599354ebf4delphij   correctness of the compressed output even if it is not set appropriately.
600354ebf4delphij   Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
601354ebf4delphij   decoder for special applications.
603354ebf4delphij     deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
604354ebf4delphij   memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
605354ebf4delphij   method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
606354ebf4delphij   incompatible with the version assumed by the caller (ZLIB_VERSION).  msg is
607354ebf4delphij   set to null if there is no error message.  deflateInit2 does not perform any
608354ebf4delphij   compression: this will be done by deflate().
611b66130epeterZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
612b66130epeter                                             const Bytef *dictionary,
613b66130epeter                                             uInt  dictLength));
6159f86c0bsteve     Initializes the compression dictionary from the given byte sequence
616abe1867delphij   without producing any compressed output.  When using the zlib format, this
617abe1867delphij   function must be called immediately after deflateInit, deflateInit2 or
618abe1867delphij   deflateReset, and before any call of deflate.  When doing raw deflate, this
619abe1867delphij   function must be called either before any call of deflate, or immediately
620abe1867delphij   after the completion of a deflate block, i.e. after all input has been
621abe1867delphij   consumed and all output has been delivered when using any of the flush
622abe1867delphij   options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH.  The
623abe1867delphij   compressor and decompressor must use exactly the same dictionary (see
624abe1867delphij   inflateSetDictionary).
62670c83c0peter     The dictionary should consist of strings (byte sequences) that are likely
62770c83c0peter   to be encountered later in the data to be compressed, with the most commonly
628354ebf4delphij   used strings preferably put towards the end of the dictionary.  Using a
6299f86c0bsteve   dictionary is most useful when the data to be compressed is short and can be
6309f86c0bsteve   predicted with good accuracy; the data can then be compressed better than
6319f86c0bsteve   with the default empty dictionary.
6339f86c0bsteve     Depending on the size of the compression data structures selected by
6349f86c0bsteve   deflateInit or deflateInit2, a part of the dictionary may in effect be
635354ebf4delphij   discarded, for example if the dictionary is larger than the window size
636354ebf4delphij   provided in deflateInit or deflateInit2.  Thus the strings most likely to be
637354ebf4delphij   useful should be put at the end of the dictionary, not at the front.  In
638354ebf4delphij   addition, the current implementation of deflate will use at most the window
639354ebf4delphij   size minus 262 bytes of the provided dictionary.
641abe96eddelphij     Upon return of this function, strm->adler is set to the Adler-32 value
64270c83c0peter   of the dictionary; the decompressor may later use this value to determine
643abe96eddelphij   which dictionary has been used by the compressor.  (The Adler-32 value
64470c83c0peter   applies to the whole dictionary even if only a subset of the dictionary is
645439ed8dtjr   actually used by the compressor.) If a raw deflate was requested, then the
646abe96eddelphij   Adler-32 value is not computed and strm->adler is not set.
64870c83c0peter     deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
649354ebf4delphij   parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
6509f86c0bsteve   inconsistent (for example if deflate has already been called for this stream
651abe1867delphij   or if not at a block boundary for raw deflate).  deflateSetDictionary does
652abe1867delphij   not perform any compression: this will be done by deflate().
655abe96eddelphijZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm,
656abe96eddelphij                                             Bytef *dictionary,
657abe96eddelphij                                             uInt  *dictLength));
659abe96eddelphij     Returns the sliding dictionary being maintained by deflate.  dictLength is
660abe96eddelphij   set to the number of bytes in the dictionary, and that many bytes are copied
661abe96eddelphij   to dictionary.  dictionary must have enough space, where 32768 bytes is
662abe96eddelphij   always enough.  If deflateGetDictionary() is called with dictionary equal to
663abe96eddelphij   Z_NULL, then only the dictionary length is returned, and nothing is copied.
664abe96eddelphij   Similary, if dictLength is Z_NULL, then it is not set.
666abe96eddelphij     deflateGetDictionary() may return a length less than the window size, even
667abe96eddelphij   when more than the window size in input has been provided. It may return up
668abe96eddelphij   to 258 bytes less in that case, due to how zlib's implementation of deflate
669abe96eddelphij   manages the sliding window and lookahead for matches, where matches can be
670abe96eddelphij   up to 258 bytes long. If the application needs the last window-size bytes of
671abe96eddelphij   input, then that would need to be saved by the application outside of zlib.
673abe96eddelphij     deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
674abe96eddelphij   stream state is inconsistent.
677b66130epeterZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
678b66130epeter                                    z_streamp source));
6809f86c0bsteve     Sets the destination stream as a complete copy of the source stream.
68270c83c0peter     This function can be useful when several compression strategies will be
68370c83c0peter   tried, for example when there are several ways of pre-processing the input
684354ebf4delphij   data with a filter.  The streams that will be discarded should then be freed
68570c83c0peter   by calling deflateEnd.  Note that deflateCopy duplicates the internal
686354ebf4delphij   compression state which can be quite large, so this strategy is slow and can
687354ebf4delphij   consume lots of memory.
68970c83c0peter     deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
69070c83c0peter   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
691354ebf4delphij   (such as zalloc being Z_NULL).  msg is left unchanged in both source and
69270c83c0peter   destination.
695b66130epeterZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
697abe96eddelphij     This function is equivalent to deflateEnd followed by deflateInit, but
698abe96eddelphij   does not free and reallocate the internal compression state.  The stream
699abe96eddelphij   will leave the compression level and any other attributes that may have been
700abe96eddelphij   set unchanged.
702354ebf4delphij     deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
703354ebf4delphij   stream state was inconsistent (such as zalloc or state being Z_NULL).
706b66130epeterZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
707439ed8dtjr                                      int level,
708439ed8dtjr                                      int strategy));
7109f86c0bsteve     Dynamically update the compression level and compression strategy.  The
711abe96eddelphij   interpretation of level and strategy is as in deflateInit2().  This can be
7129f86c0bsteve   used to switch between compression and straight copy of the input data, or
713354ebf4delphij   to switch to a different kind of input data requiring a different strategy.
714abe96eddelphij   If the compression approach (which is a function of the level) or the
715e86834emarius   strategy is changed, and if there have been any deflate() calls since the
716e86834emarius   state was initialized or reset, then the input available so far is
717e86834emarius   compressed with the old level and strategy using deflate(strm, Z_BLOCK).
718e86834emarius   There are three approaches for the compression levels 0, 1..3, and 4..9
719e86834emarius   respectively.  The new level and strategy will take effect at the next call
720e86834emarius   of deflate().
722abe96eddelphij     If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
723abe96eddelphij   not have enough output space to complete, then the parameter change will not
724abe96eddelphij   take effect.  In this case, deflateParams() can be called again with the
725abe96eddelphij   same parameters and more output space to try again.
727abe96eddelphij     In order to assure a change in the parameters on the first try, the
728abe96eddelphij   deflate stream should be flushed using deflate() with Z_BLOCK or other flush
729abe96eddelphij   request until strm.avail_out is not zero, before calling deflateParams().
730abe96eddelphij   Then no more input data should be provided before the deflateParams() call.
731abe96eddelphij   If this is done, the old level and strategy will be applied to the data
732abe96eddelphij   compressed before deflateParams(), and the new level and strategy will be
733abe96eddelphij   applied to the the data compressed after deflateParams().
735abe96eddelphij     deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
736abe96eddelphij   state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
737abe96eddelphij   there was not enough output space to complete the compression of the
738abe96eddelphij   available input data before a change in the strategy or approach.  Note that
739abe96eddelphij   in the case of a Z_BUF_ERROR, the parameters are not changed.  A return
740abe96eddelphij   value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
741abe96eddelphij   retried with more output space.
744caf24dddesZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
745caf24dddes                                    int good_length,
746caf24dddes                                    int max_lazy,
747caf24dddes                                    int nice_length,
748caf24dddes                                    int max_chain));
750caf24dddes     Fine tune deflate's internal compression parameters.  This should only be
751caf24dddes   used by someone who understands the algorithm used by zlib's deflate for
752caf24dddes   searching for the best matching string, and even then only by the most
753caf24dddes   fanatic optimizer trying to squeeze out the last compressed bit for their
754caf24dddes   specific input data.  Read the deflate.c source code for the meaning of the
755caf24dddes   max_lazy, good_length, nice_length, and max_chain parameters.
757caf24dddes     deflateTune() can be called after deflateInit() or deflateInit2(), and
758caf24dddes   returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
759caf24dddes */
761439ed8dtjrZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
762439ed8dtjr                                       uLong sourceLen));
764439ed8dtjr     deflateBound() returns an upper bound on the compressed size after
765354ebf4delphij   deflation of sourceLen bytes.  It must be called after deflateInit() or
766354ebf4delphij   deflateInit2(), and after deflateSetHeader(), if used.  This would be used
767354ebf4delphij   to allocate an output buffer for deflation in a single pass, and so would be
768abe1867delphij   called before deflate().  If that first deflate() call is provided the
769abe1867delphij   sourceLen input bytes, an output buffer allocated to the size returned by
770abe1867delphij   deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
771abe1867delphij   to return Z_STREAM_END.  Note that it is possible for the compressed size to
772abe1867delphij   be larger than the value returned by deflateBound() if flush options other
773abe1867delphij   than Z_FINISH or Z_NO_FLUSH are used.
776abe1867delphijZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
777abe1867delphij                                       unsigned *pending,
778abe1867delphij                                       int *bits));
780abe1867delphij     deflatePending() returns the number of bytes and bits of output that have
781abe1867delphij   been generated, but not yet provided in the available output.  The bytes not
782abe1867delphij   provided would be due to the available output space having being consumed.
783abe1867delphij   The number of bits of output not provided are between 0 and 7, where they
784abe1867delphij   await more bits to join them in order to fill out a full byte.  If pending
785abe1867delphij   or bits are Z_NULL, then those values are not set.
787abe1867delphij     deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
788abe1867delphij   stream state was inconsistent.
789abe1867delphij */
791439ed8dtjrZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
792439ed8dtjr                                     int bits,
793439ed8dtjr                                     int value));
795439ed8dtjr     deflatePrime() inserts bits in the deflate output stream.  The intent
796354ebf4delphij   is that this function is used to start off the deflate output with the bits
797354ebf4delphij   leftover from a previous deflate stream when appending to it.  As such, this
798354ebf4delphij   function can only be used for raw deflate, and must be used before the first
799354ebf4delphij   deflate() call after a deflateInit2() or deflateReset().  bits must be less
800354ebf4delphij   than or equal to 16, and that many of the least significant bits of value
801354ebf4delphij   will be inserted in the output.
803abe1867delphij     deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
804abe1867delphij   room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
805abe1867delphij   source stream state was inconsistent.
808caf24dddesZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
809caf24dddes                                         gz_headerp head));
811354ebf4delphij     deflateSetHeader() provides gzip header information for when a gzip
812caf24dddes   stream is requested by deflateInit2().  deflateSetHeader() may be called
813caf24dddes   after deflateInit2() or deflateReset() and before the first call of
814caf24dddes   deflate().  The text, time, os, extra field, name, and comment information
815caf24dddes   in the provided gz_header structure are written to the gzip header (xflag is
816caf24dddes   ignored -- the extra flags are set according to the compression level).  The
817caf24dddes   caller must assure that, if not Z_NULL, name and comment are terminated with
818caf24dddes   a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
819caf24dddes   available there.  If hcrc is true, a gzip header crc is included.  Note that
820caf24dddes   the current versions of the command-line version of gzip (up through version
821caf24dddes   1.3.x) do not support header crc's, and will report that it is a "multi-part
822caf24dddes   gzip file" and give up.
824354ebf4delphij     If deflateSetHeader is not used, the default gzip header has text false,
825caf24dddes   the time set to zero, and os set to 255, with no extra, name, or comment
826caf24dddes   fields.  The gzip header is returned to the default state by deflateReset().
828354ebf4delphij     deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
829caf24dddes   stream state was inconsistent.
833b66130epeterZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
834b66130epeter                                     int  windowBits));
836354ebf4delphij     This is another version of inflateInit with an extra parameter.  The
8379f86c0bsteve   fields next_in, avail_in, zalloc, zfree and opaque must be initialized
8389f86c0bsteve   before by the caller.
84070c83c0peter     The windowBits parameter is the base two logarithm of the maximum window
84170c83c0peter   size (the size of the history buffer).  It should be in the range 8..15 for
842354ebf4delphij   this version of the library.  The default value is 15 if inflateInit is used
843354ebf4delphij   instead.  windowBits must be greater than or equal to the windowBits value
844439ed8dtjr   provided to deflateInit2() while compressing, or it must be equal to 15 if
845354ebf4delphij   deflateInit2() was not used.  If a compressed stream with a larger window
846439ed8dtjr   size is given as input, inflate() will return with the error code
847439ed8dtjr   Z_DATA_ERROR instead of trying to allocate a larger window.
849354ebf4delphij     windowBits can also be zero to request that inflate use the window size in
850354ebf4delphij   the zlib header of the compressed stream.
852354ebf4delphij     windowBits can also be -8..-15 for raw inflate.  In this case, -windowBits
853354ebf4delphij   determines the window size.  inflate() will then process raw deflate data,
854439ed8dtjr   not looking for a zlib or gzip header, not generating a check value, and not
855354ebf4delphij   looking for any check values for comparison at the end of the stream.  This
856439ed8dtjr   is for use with other formats that use the deflate compressed data format
857354ebf4delphij   such as zip.  Those formats provide their own check values.  If a custom
858439ed8dtjr   format is developed using the raw deflate format for compressed data, it is
859abe96eddelphij   recommended that a check value such as an Adler-32 or a CRC-32 be applied to
860439ed8dtjr   the uncompressed data as is done in the zlib, gzip, and zip formats.  For
861354ebf4delphij   most applications, the zlib format should be used as is.  Note that comments
862439ed8dtjr   above on the use in deflateInit2() applies to the magnitude of windowBits.
864354ebf4delphij     windowBits can also be greater than 15 for optional gzip decoding.  Add
865439ed8dtjr   32 to windowBits to enable zlib and gzip decoding with automatic header
866439ed8dtjr   detection, or add 16 to decode only the gzip format (the zlib format will
867354ebf4delphij   return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is a
868abe96eddelphij   CRC-32 instead of an Adler-32.  Unlike the gunzip utility and gzread() (see
869abe96eddelphij   below), inflate() will not automatically decode concatenated gzip streams.
870abe96eddelphij   inflate() will return Z_STREAM_END at the end of the gzip stream.  The state
871abe96eddelphij   would need to be reset to continue decoding a subsequent gzip stream.
873439ed8dtjr     inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
874354ebf4delphij   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
875354ebf4delphij   version assumed by the caller, or Z_STREAM_ERROR if the parameters are
876354ebf4delphij   invalid, such as a null pointer to the structure.  msg is set to null if
877354ebf4delphij   there is no error message.  inflateInit2 does not perform any decompression
878354ebf4delphij   apart from possibly reading the zlib header if present: actual decompression
879354ebf4delphij   will be done by inflate().  (So next_in and avail_in may be modified, but
880354ebf4delphij   next_out and avail_out are unused and unchanged.) The current implementation
881354ebf4delphij   of inflateInit2() does not process any header information -- that is
882354ebf4delphij   deferred until inflate() is called.
885b66130epeterZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
886b66130epeter                                             const Bytef *dictionary,
887b66130epeter                                             uInt  dictLength));
8899f86c0bsteve     Initializes the decompression dictionary from the given uncompressed byte
890354ebf4delphij   sequence.  This function must be called immediately after a call of inflate,
891354ebf4delphij   if that call returned Z_NEED_DICT.  The dictionary chosen by the compressor
892abe96eddelphij   can be determined from the Adler-32 value returned by that call of inflate.
893caf24dddes   The compressor and decompressor must use exactly the same dictionary (see
894abe1867delphij   deflateSetDictionary).  For raw inflate, this function can be called at any
895abe1867delphij   time to set the dictionary.  If the provided dictionary is smaller than the
896abe1867delphij   window and there is already data in the window, then the provided dictionary
897abe1867delphij   will amend what's there.  The application must insure that the dictionary
898abe1867delphij   that was used for compression is provided.
90070c83c0peter     inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
901354ebf4delphij   parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
90270c83c0peter   inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
903abe96eddelphij   expected one (incorrect Adler-32 value).  inflateSetDictionary does not
90470c83c0peter   perform any decompression: this will be done by subsequent calls of
90570c83c0peter   inflate().
9083aa8c3cdelphijZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
9093aa8c3cdelphij                                             Bytef *dictionary,
9103aa8c3cdelphij                                             uInt  *dictLength));
9123aa8c3cdelphij     Returns the sliding dictionary being maintained by inflate.  dictLength is
9133aa8c3cdelphij   set to the number of bytes in the dictionary, and that many bytes are copied
9143aa8c3cdelphij   to dictionary.  dictionary must have enough space, where 32768 bytes is
9153aa8c3cdelphij   always enough.  If inflateGetDictionary() is called with dictionary equal to
9163aa8c3cdelphij   Z_NULL, then only the dictionary length is returned, and nothing is copied.
9173aa8c3cdelphij   Similary, if dictLength is Z_NULL, then it is not set.
9193aa8c3cdelphij     inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
9203aa8c3cdelphij   stream state is inconsistent.
923b66130epeterZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
925abe1867delphij     Skips invalid compressed data until a possible full flush point (see above
926abe1867delphij   for the description of deflate with Z_FULL_FLUSH) can be found, or until all
927354ebf4delphij   available input is skipped.  No output is provided.
929abe1867delphij     inflateSync searches for a 00 00 FF FF pattern in the compressed data.
930d3ee8e3gabor   All full flush points have this pattern, but not all occurrences of this
931abe1867delphij   pattern are full flush points.
933abe1867delphij     inflateSync returns Z_OK if a possible full flush point has been found,
934abe1867delphij   Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
935abe1867delphij   has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
936abe1867delphij   In the success case, the application may save the current current value of
937abe1867delphij   total_in which indicates where valid compressed data was found.  In the
938abe1867delphij   error case, the application may repeatedly call inflateSync, providing more
939abe1867delphij   input each time, until success or end of the input data.
942439ed8dtjrZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
943439ed8dtjr                                    z_streamp source));
945439ed8dtjr     Sets the destination stream as a complete copy of the source stream.
947439ed8dtjr     This function can be useful when randomly accessing a large stream.  The
948439ed8dtjr   first pass through the stream can periodically record the inflate state,
949439ed8dtjr   allowing restarting inflate at those points when randomly accessing the
950439ed8dtjr   stream.
952439ed8dtjr     inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
953439ed8dtjr   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
954354ebf4delphij   (such as zalloc being Z_NULL).  msg is left unchanged in both source and
955439ed8dtjr   destination.
958b66130epeterZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
96070c83c0peter     This function is equivalent to inflateEnd followed by inflateInit,
961abe96eddelphij   but does not free and reallocate the internal decompression state.  The
962354ebf4delphij   stream will keep attributes that may have been set by inflateInit2.
964354ebf4delphij     inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
965354ebf4delphij   stream state was inconsistent (such as zalloc or state being Z_NULL).
968354ebf4delphijZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
969354ebf4delphij                                      int windowBits));
971354ebf4delphij     This function is the same as inflateReset, but it also permits changing
972354ebf4delphij   the wrap and window size requests.  The windowBits parameter is interpreted
973abe96eddelphij   the same as it is for inflateInit2.  If the window size is changed, then the
974abe96eddelphij   memory allocated for the window is freed, and the window will be reallocated
975abe96eddelphij   by inflate() if needed.
977354ebf4delphij     inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
978354ebf4delphij   stream state was inconsistent (such as zalloc or state being Z_NULL), or if
979354ebf4delphij   the windowBits parameter is invalid.
982caf24dddesZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
983caf24dddes                                     int bits,
984caf24dddes                                     int value));
986caf24dddes     This function inserts bits in the inflate input stream.  The intent is
987354ebf4delphij   that this function is used to start inflating at a bit position in the
988354ebf4delphij   middle of a byte.  The provided bits will be used before any bytes are used
989354ebf4delphij   from next_in.  This function should only be used with raw inflate, and
990354ebf4delphij   should be used before the first inflate() call after inflateInit2() or
991354ebf4delphij   inflateReset().  bits must be less than or equal to 16, and that many of the
992354ebf4delphij   least significant bits of value will be inserted in the input.
994354ebf4delphij     If bits is negative, then the input stream bit buffer is emptied.  Then
995354ebf4delphij   inflatePrime() can be called again to put bits in the buffer.  This is used
996354ebf4delphij   to clear out bits leftover after feeding inflate a block description prior
997354ebf4delphij   to feeding inflate codes.
999354ebf4delphij     inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
1000caf24dddes   stream state was inconsistent.
1003354ebf4delphijZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
1005354ebf4delphij     This function returns two values, one in the lower 16 bits of the return
1006354ebf4delphij   value, and the other in the remaining upper bits, obtained by shifting the
1007354ebf4delphij   return value down 16 bits.  If the upper value is -1 and the lower value is
1008354ebf4delphij   zero, then inflate() is currently decoding information outside of a block.
1009354ebf4delphij   If the upper value is -1 and the lower value is non-zero, then inflate is in
1010354ebf4delphij   the middle of a stored block, with the lower value equaling the number of
1011354ebf4delphij   bytes from the input remaining to copy.  If the upper value is not -1, then
1012354ebf4delphij   it is the number of bits back from the current bit position in the input of
1013354ebf4delphij   the code (literal or length/distance pair) currently being processed.  In
1014354ebf4delphij   that case the lower value is the number of bytes already emitted for that
1015354ebf4delphij   code.
1017354ebf4delphij     A code is being processed if inflate is waiting for more input to complete
1018354ebf4delphij   decoding of the code, or if it has completed decoding but is waiting for
1019354ebf4delphij   more output space to write the literal or match data.
1021354ebf4delphij     inflateMark() is used to mark locations in the input data for random
1022354ebf4delphij   access, which may be at bit positions, and to note those cases where the
1023354ebf4delphij   output of a code may span boundaries of random access blocks.  The current
1024354ebf4delphij   location in the input stream can be determined from avail_in and data_type
1025354ebf4delphij   as noted in the description for the Z_BLOCK flush parameter for inflate.
1027abe96eddelphij     inflateMark returns the value noted above, or -65536 if the provided
1028354ebf4delphij   source stream state was inconsistent.
1031caf24dddesZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
1032caf24dddes                                         gz_headerp head));
1034354ebf4delphij     inflateGetHeader() requests that gzip header information be stored in the
1035caf24dddes   provided gz_header structure.  inflateGetHeader() may be called after
1036caf24dddes   inflateInit2() or inflateReset(), and before the first call of inflate().
1037caf24dddes   As inflate() processes the gzip stream, head->done is zero until the header
1038caf24dddes   is completed, at which time head->done is set to one.  If a zlib stream is
1039caf24dddes   being decoded, then head->done is set to -1 to indicate that there will be
1040354ebf4delphij   no gzip header information forthcoming.  Note that Z_BLOCK or Z_TREES can be
1041354ebf4delphij   used to force inflate() to return immediately after header processing is
1042354ebf4delphij   complete and before any actual data is decompressed.
1044354ebf4delphij     The text, time, xflags, and os fields are filled in with the gzip header
1045caf24dddes   contents.  hcrc is set to true if there is a header CRC.  (The header CRC
1046354ebf4delphij   was valid if done is set to one.) If extra is not Z_NULL, then extra_max
1047caf24dddes   contains the maximum number of bytes to write to extra.  Once done is true,
1048caf24dddes   extra_len contains the actual extra field length, and extra contains the
1049caf24dddes   extra field, or that field truncated if extra_max is less than extra_len.
1050caf24dddes   If name is not Z_NULL, then up to name_max characters are written there,
1051caf24dddes   terminated with a zero unless the length is greater than name_max.  If
1052caf24dddes   comment is not Z_NULL, then up to comm_max characters are written there,
1053354ebf4delphij   terminated with a zero unless the length is greater than comm_max.  When any
1054354ebf4delphij   of extra, name, or comment are not Z_NULL and the respective field is not
1055354ebf4delphij   present in the header, then that field is set to Z_NULL to signal its
1056caf24dddes   absence.  This allows the use of deflateSetHeader() with the returned
1057caf24dddes   structure to duplicate the header.  However if those fields are set to
1058caf24dddes   allocated memory, then the application will need to save those pointers
1059caf24dddes   elsewhere so that they can be eventually freed.
1061354ebf4delphij     If inflateGetHeader is not used, then the header information is simply
1062caf24dddes   discarded.  The header is always checked for validity, including the header
1063caf24dddes   CRC if present.  inflateReset() will reset the process to discard the header
1064caf24dddes   information.  The application would need to call inflateGetHeader() again to
1065caf24dddes   retrieve the header from the next gzip stream.
1067354ebf4delphij     inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1068caf24dddes   stream state was inconsistent.
1072caf24dddesZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
1073439ed8dtjr                                        unsigned char FAR *window));
1075439ed8dtjr     Initialize the internal stream state for decompression using inflateBack()
1076439ed8dtjr   calls.  The fields zalloc, zfree and opaque in strm must be initialized
1077439ed8dtjr   before the call.  If zalloc and zfree are Z_NULL, then the default library-
1078439ed8dtjr   derived memory allocation routines are used.  windowBits is the base two
1079439ed8dtjr   logarithm of the window size, in the range 8..15.  window is a caller
1080439ed8dtjr   supplied buffer of that size.  Except for special applications where it is
1081439ed8dtjr   assured that deflate was used with small window sizes, windowBits must be 15
1082439ed8dtjr   and a 32K byte window must be supplied to be able to decompress general
1083439ed8dtjr   deflate streams.
1085439ed8dtjr     See inflateBack() for the usage of these routines.
1087439ed8dtjr     inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1088abe1867delphij   the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1089354ebf4delphij   allocated, or Z_VERSION_ERROR if the version of the library does not match
1090354ebf4delphij   the version of the header file.
10933aa8c3cdelphijtypedef unsigned (*in_func) OF((void FAR *,
10943aa8c3cdelphij                                z_const unsigned char FAR * FAR *));
1095439ed8dtjrtypedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
1097caf24dddesZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
1098439ed8dtjr                                    in_func in, void FAR *in_desc,
1099439ed8dtjr                                    out_func out, void FAR *out_desc));
1101439ed8dtjr     inflateBack() does a raw inflate with a single call using a call-back
11023aa8c3cdelphij   interface for input and output.  This is potentially more efficient than
11033aa8c3cdelphij   inflate() for file i/o applications, in that it avoids copying between the
11043aa8c3cdelphij   output and the sliding window by simply making the window itself the output
11053aa8c3cdelphij   buffer.  inflate() can be faster on modern CPUs when used with large
11063aa8c3cdelphij   buffers.  inflateBack() trusts the application to not change the output
11073aa8c3cdelphij   buffer passed by the output function, at least until inflateBack() returns.
1109439ed8dtjr     inflateBackInit() must be called first to allocate the internal state
1110439ed8dtjr   and to initialize the state with the user-provided window buffer.
1111439ed8dtjr   inflateBack() may then be used multiple times to inflate a complete, raw
1112354ebf4delphij   deflate stream with each call.  inflateBackEnd() is then called to free the
1113354ebf4delphij   allocated state.
1115439ed8dtjr     A raw deflate stream is one with no zlib or gzip header or trailer.
1116439ed8dtjr   This routine would normally be used in a utility that reads zip or gzip
1117439ed8dtjr   files and writes out uncompressed files.  The utility would decode the
1118354ebf4delphij   header and process the trailer on its own, hence this routine expects only
1119abe96eddelphij   the raw deflate stream to decompress.  This is different from the default
1120abe96eddelphij   behavior of inflate(), which expects a zlib header and trailer around the
1121abe96eddelphij   deflate stream.
1123439ed8dtjr     inflateBack() uses two subroutines supplied by the caller that are then
1124439ed8dtjr   called by inflateBack() for input and output.  inflateBack() calls those
1125439ed8dtjr   routines until it reads a complete deflate stream and writes out all of the
1126439ed8dtjr   uncompressed data, or until it encounters an error.  The function's
1127439ed8dtjr   parameters and return types are defined above in the in_func and out_func
1128439ed8dtjr   typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
1129439ed8dtjr   number of bytes of provided input, and a pointer to that input in buf.  If
1130abe96eddelphij   there is no input available, in() must return zero -- buf is ignored in that
1131abe96eddelphij   case -- and inflateBack() will return a buffer error.  inflateBack() will
1132abe96eddelphij   call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
1133abe96eddelphij   out() should return zero on success, or non-zero on failure.  If out()
1134abe96eddelphij   returns non-zero, inflateBack() will return with an error.  Neither in() nor
1135abe96eddelphij   out() are permitted to change the contents of the window provided to
1136439ed8dtjr   inflateBackInit(), which is also the buffer that out() uses to write from.
1137439ed8dtjr   The length written by out() will be at most the window size.  Any non-zero
1138439ed8dtjr   amount of input may be provided by in().
1140439ed8dtjr     For convenience, inflateBack() can be provided input on the first call by
1141439ed8dtjr   setting strm->next_in and strm->avail_in.  If that input is exhausted, then
1142439ed8dtjr   in() will be called.  Therefore strm->next_in must be initialized before
1143439ed8dtjr   calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
1144439ed8dtjr   immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
1145439ed8dtjr   must also be initialized, and then if strm->avail_in is not zero, input will
1146354ebf4delphij   initially be taken from strm->next_in[0 ..  strm->avail_in - 1].
1148439ed8dtjr     The in_desc and out_desc parameters of inflateBack() is passed as the
1149439ed8dtjr   first parameter of in() and out() respectively when they are called.  These
1150439ed8dtjr   descriptors can be optionally used to pass any information that the caller-
1151439ed8dtjr   supplied in() and out() functions need to do their job.
1153439ed8dtjr     On return, inflateBack() will set strm->next_in and strm->avail_in to
1154439ed8dtjr   pass back any unused input that was provided by the last in() call.  The
1155439ed8dtjr   return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1156354ebf4delphij   if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1157354ebf4delphij   in the deflate stream (in which case strm->msg is set to indicate the nature
1158354ebf4delphij   of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1159354ebf4delphij   In the case of Z_BUF_ERROR, an input or output error can be distinguished
1160354ebf4delphij   using strm->next_in which will be Z_NULL only if in() returned an error.  If
1161354ebf4delphij   strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1162354ebf4delphij   non-zero.  (in() will always be called before out(), so strm->next_in is
1163abe96eddelphij   assured to be defined if out() returns non-zero.)  Note that inflateBack()
1164354ebf4delphij   cannot return Z_OK.
1167caf24dddesZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
1169439ed8dtjr     All memory allocated by inflateBackInit() is freed.
1171439ed8dtjr     inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1172439ed8dtjr   state was inconsistent.
1175439ed8dtjrZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
1176439ed8dtjr/* Return flags indicating compile-time options.
1178439ed8dtjr    Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1179439ed8dtjr     1.0: size of uInt
1180439ed8dtjr     3.2: size of uLong
1181439ed8dtjr     5.4: size of voidpf (pointer)
1182439ed8dtjr     7.6: size of z_off_t
1184439ed8dtjr    Compiler, assembler, and debug options:
1185abe96eddelphij     8: ZLIB_DEBUG
1186439ed8dtjr     9: ASMV or ASMINF -- use ASM code
1187439ed8dtjr     10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1188439ed8dtjr     11: 0 (reserved)
1190439ed8dtjr    One-time table building (smaller code, but not thread-safe if true):
1191439ed8dtjr     12: BUILDFIXED -- build static block decoding tables when needed
1192439ed8dtjr     13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1193439ed8dtjr     14,15: 0 (reserved)
1195439ed8dtjr    Library content (indicates missing functionality):
1196439ed8dtjr     16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1197439ed8dtjr                          deflate code when not needed)
1198439ed8dtjr     17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1199439ed8dtjr                    and decode gzip streams (to avoid linking crc code)
1200439ed8dtjr     18-19: 0 (reserved)
1202439ed8dtjr    Operation variations (changes in library functionality):
1203439ed8dtjr     20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1204439ed8dtjr     21: FASTEST -- deflate algorithm with only one, lowest compression level
1205439ed8dtjr     22,23: 0 (reserved)
1207439ed8dtjr    The sprintf variant used by gzprintf (zero is best):
1208439ed8dtjr     24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1209439ed8dtjr     25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1210439ed8dtjr     26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1212439ed8dtjr    Remainder:
1213439ed8dtjr     27-31: 0 (reserved)
1214439ed8dtjr */
121603ea53cdelphij#if !defined(Z_SOLO) || defined(_KERNEL)
121870c83c0peter                        /* utility functions */
1221354ebf4delphij     The following utility functions are implemented on top of the basic
1222354ebf4delphij   stream-oriented functions.  To simplify the interface, some default options
1223354ebf4delphij   are assumed (compression level and memory usage, standard memory allocation
1224354ebf4delphij   functions).  The source code of these utility functions can be modified if
1225354ebf4delphij   you need special options.
1228b66130epeterZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
1229b66130epeter                                 const Bytef *source, uLong sourceLen));
123170c83c0peter     Compresses the source buffer into the destination buffer.  sourceLen is
1232354ebf4delphij   the byte length of the source buffer.  Upon entry, destLen is the total size
1233354ebf4delphij   of the destination buffer, which must be at least the value returned by
1234354ebf4delphij   compressBound(sourceLen).  Upon exit, destLen is the actual size of the
1235abe96eddelphij   compressed data.  compress() is equivalent to compress2() with a level
1236abe96eddelphij   parameter of Z_DEFAULT_COMPRESSION.
123870c83c0peter     compress returns Z_OK if success, Z_MEM_ERROR if there was not
123970c83c0peter   enough memory, Z_BUF_ERROR if there was not enough room in the output
124070c83c0peter   buffer.
1243b66130epeterZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
1244b66130epeter                                  const Bytef *source, uLong sourceLen,
1245b66130epeter                                  int level));
1247354ebf4delphij     Compresses the source buffer into the destination buffer.  The level
12489f86c0bsteve   parameter has the same meaning as in deflateInit.  sourceLen is the byte
1249354ebf4delphij   length of the source buffer.  Upon entry, destLen is the total size of the
1250439ed8dtjr   destination buffer, which must be at least the value returned by
1251354ebf4delphij   compressBound(sourceLen).  Upon exit, destLen is the actual size of the
1252abe96eddelphij   compressed data.
12549f86c0bsteve     compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
12559f86c0bsteve   memory, Z_BUF_ERROR if there was not enough room in the output buffer,
12569f86c0bsteve   Z_STREAM_ERROR if the level parameter is invalid.
1259439ed8dtjrZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
1261439ed8dtjr     compressBound() returns an upper bound on the compressed size after
1262354ebf4delphij   compress() or compress2() on sourceLen bytes.  It would be used before a
1263354ebf4delphij   compress() or compress2() call to allocate the destination buffer.
1266b66130epeterZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
1267b66130epeter                                   const Bytef *source, uLong sourceLen));
126970c83c0peter     Decompresses the source buffer into the destination buffer.  sourceLen is
1270354ebf4delphij   the byte length of the source buffer.  Upon entry, destLen is the total size
1271354ebf4delphij   of the destination buffer, which must be large enough to hold the entire
1272354ebf4delphij   uncompressed data.  (The size of the uncompressed data must have been saved
1273354ebf4delphij   previously by the compressor and transmitted to the decompressor by some
1274354ebf4delphij   mechanism outside the scope of this compression library.) Upon exit, destLen
1275abe96eddelphij   is the actual size of the uncompressed data.
127770c83c0peter     uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
127870c83c0peter   enough memory, Z_BUF_ERROR if there was not enough room in the output
1279abe1867delphij   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.  In
1280abe1867delphij   the case where there is not enough room, uncompress() will fill the output
1281abe1867delphij   buffer with the uncompressed data up to that point.
1284abe96eddelphijZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest,   uLongf *destLen,
1285abe96eddelphij                                    const Bytef *source, uLong *sourceLen));
1287abe96eddelphij     Same as uncompress, except that sourceLen is a pointer, where the
1288abe96eddelphij   length of the source is *sourceLen.  On return, *sourceLen is the number of
1289abe96eddelphij   source bytes consumed.
129103ea53cdelphij#endif /* !Z_SOLO || _KERNEL */
129303ea53cdelphij#ifndef Z_SOLO
1295354ebf4delphij                        /* gzip file access functions */
1298354ebf4delphij     This library supports reading and writing files in gzip (.gz) format with
1299354ebf4delphij   an interface similar to that of stdio, using the functions that start with
1300354ebf4delphij   "gz".  The gzip format is different from the zlib format.  gzip is a gzip
1301354ebf4delphij   wrapper, documented in RFC 1952, wrapped around a deflate stream.
1304abe1867delphijtypedef struct gzFile_s *gzFile;    /* semi-opaque gzip file descriptor */
1307354ebf4delphijZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
1309354ebf4delphij     Opens a gzip (.gz) file for reading or writing.  The mode parameter is as
1310354ebf4delphij   in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1311354ebf4delphij   a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1312354ebf4delphij   compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1313354ebf4delphij   for fixed code compression as in "wb9F".  (See the description of
1314abe1867delphij   deflateInit2 for more information about the strategy parameter.)  'T' will
1315abe1867delphij   request transparent writing or appending with no compression and not using
1316abe1867delphij   the gzip format.
1318abe1867delphij     "a" can be used instead of "w" to request that the gzip stream that will
1319abe1867delphij   be written be appended to the file.  "+" will result in an error, since
13205ecec51delphij   reading and writing to the same gzip file is not supported.  The addition of
13215ecec51delphij   "x" when writing will create the file exclusively, which fails if the file
13225ecec51delphij   already exists.  On systems that support it, the addition of "e" when
13235ecec51delphij   reading or writing will set the flag to close the file on an execve() call.
1325abe1867delphij     These functions, as well as gzip, will read and decode a sequence of gzip
1326abe1867delphij   streams in a file.  The append function of gzopen() can be used to create
1327abe1867delphij   such a file.  (Also see gzflush() for another way to do this.)  When
1328abe1867delphij   appending, gzopen does not test whether the file begins with a gzip stream,
1329abe1867delphij   nor does it look for the end of the gzip streams to begin appending.  gzopen
1330abe1867delphij   will simply append a gzip stream to the existing file.
13329f86c0bsteve     gzopen can be used to read a file which is not in gzip format; in this
1333abe1867delphij   case gzread will directly read from the file without decompression.  When
1334abe1867delphij   reading, this will be detected automatically by looking for the magic two-
1335abe1867delphij   byte gzip header.
1337354ebf4delphij     gzopen returns NULL if the file could not be opened, if there was
1338354ebf4delphij   insufficient memory to allocate the gzFile state, or if an invalid mode was
1339354ebf4delphij   specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1340354ebf4delphij   errno can be checked to determine if the reason gzopen failed was that the
1341354ebf4delphij   file could not be opened.
1344354ebf4delphijZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
1346354ebf4delphij     gzdopen associates a gzFile with the file descriptor fd.  File descriptors
1347354ebf4delphij   are obtained from calls like open, dup, creat, pipe or fileno (if the file
1348354ebf4delphij   has been previously opened with fopen).  The mode parameter is as in gzopen.
1350354ebf4delphij     The next call of gzclose on the returned gzFile will also close the file
1351354ebf4delphij   descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1352354ebf4delphij   fd.  If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1353354ebf4delphij   mode);.  The duplicated descriptor should be saved to avoid a leak, since
1354abe1867delphij   gzdopen does not close fd if it fails.  If you are using fileno() to get the
1355abe1867delphij   file descriptor from a FILE *, then you will have to use dup() to avoid
1356abe1867delphij   double-close()ing the file descriptor.  Both gzclose() and fclose() will
1357abe1867delphij   close the associated file descriptor, so they need to have different file
1358abe1867delphij   descriptors.
1360354ebf4delphij     gzdopen returns NULL if there was insufficient memory to allocate the
1361354ebf4delphij   gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1362354ebf4delphij   provided, or '+' was provided), or if fd is -1.  The file descriptor is not
1363354ebf4delphij   used until the next gz* read, write, seek, or close operation, so gzdopen
1364354ebf4delphij   will not detect if fd is invalid (unless fd is -1).
1367354ebf4delphijZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
1369354ebf4delphij     Set the internal buffer size used by this library's functions.  The
1370354ebf4delphij   default buffer size is 8192 bytes.  This function must be called after
1371354ebf4delphij   gzopen() or gzdopen(), and before any other calls that read or write the
1372354ebf4delphij   file.  The buffer memory allocation is always deferred to the first read or
1373abe96eddelphij   write.  Three times that size in buffer space is allocated.  A larger buffer
1374abe96eddelphij   size of, for example, 64K or 128K bytes will noticeably increase the speed
1375abe96eddelphij   of decompression (reading).
1377354ebf4delphij     The new buffer size also affects the maximum length for gzprintf().
1379354ebf4delphij     gzbuffer() returns 0 on success, or -1 on failure, such as being called
1380354ebf4delphij   too late.
1383b66130epeterZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
1385354ebf4delphij     Dynamically update the compression level or strategy.  See the description
1386abe96eddelphij   of deflateInit2 for the meaning of these parameters.  Previously provided
1387abe96eddelphij   data is flushed before the parameter change.
1389abe96eddelphij     gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
1390abe96eddelphij   opened for writing, Z_ERRNO if there is an error writing the flushed data,
1391abe96eddelphij   or Z_MEM_ERROR if there is a memory allocation error.
1394354ebf4delphijZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
1396354ebf4delphij     Reads the given number of uncompressed bytes from the compressed file.  If
1397abe1867delphij   the input file is not in gzip format, gzread copies the given number of
1398abe1867delphij   bytes into the buffer directly from the file.
1400354ebf4delphij     After reaching the end of a gzip stream in the input, gzread will continue
1401abe1867delphij   to read, looking for another gzip stream.  Any number of gzip streams may be
1402abe1867delphij   concatenated in the input file, and will all be decompressed by gzread().
1403abe1867delphij   If something other than a gzip stream is encountered after a gzip stream,
1404abe1867delphij   that remaining trailing garbage is ignored (and no error is returned).
1406abe1867delphij     gzread can be used to read a gzip file that is being concurrently written.
1407abe1867delphij   Upon reaching the end of the input, gzread will return with the available
1408abe1867delphij   data.  If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1409abe1867delphij   gzclearerr can be used to clear the end of file indicator in order to permit
1410abe1867delphij   gzread to be tried again.  Z_OK indicates that a gzip stream was completed
1411abe1867delphij   on the last gzread.  Z_BUF_ERROR indicates that the input file ended in the
1412abe1867delphij   middle of a gzip stream.  Note that gzread does not return -1 in the event
1413abe1867delphij   of an incomplete gzip stream.  This error is deferred until gzclose(), which
1414abe1867delphij   will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1415abe1867delphij   stream.  Alternatively, gzerror can be used before gzclose to detect this
1416abe1867delphij   case.
1418354ebf4delphij     gzread returns the number of uncompressed bytes actually read, less than
1419abe96eddelphij   len for end of file, or -1 for error.  If len is too large to fit in an int,
1420abe96eddelphij   then nothing is read, -1 is returned, and the error state is set to
1421abe96eddelphij   Z_STREAM_ERROR.
1424abe96eddelphijZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems,
1425abe96eddelphij                                     gzFile file));
1427abe96eddelphij     Read up to nitems items of size size from file to buf, otherwise operating
1428abe96eddelphij   as gzread() does.  This duplicates the interface of stdio's fread(), with
1429abe96eddelphij   size_t request and return types.  If the library defines size_t, then
1430abe96eddelphij   z_size_t is identical to size_t.  If not, then z_size_t is an unsigned
1431abe96eddelphij   integer type that can contain a pointer.
1433abe96eddelphij     gzfread() returns the number of full items read of size size, or zero if
1434abe96eddelphij   the end of the file was reached and a full item could not be read, or if
1435abe96eddelphij   there was an error.  gzerror() must be consulted if zero is returned in
1436abe96eddelphij   order to determine if there was an error.  If the multiplication of size and
1437abe96eddelphij   nitems overflows, i.e. the product does not fit in a z_size_t, then nothing
1438abe96eddelphij   is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
1440abe96eddelphij     In the event that the end of file is reached and only a partial item is
1441abe96eddelphij   available at the end, i.e. the remaining uncompressed data length is not a
1442abe96eddelphij   multiple of size, then the final partial item is nevetheless read into buf
1443abe96eddelphij   and the end-of-file flag is set.  The length of the partial item read is not
1444abe96eddelphij   provided, but could be inferred from the result of gztell().  This behavior
1445abe96eddelphij   is the same as the behavior of fread() implementations in common libraries,
1446abe96eddelphij   but it prevents the direct use of gzfread() to read a concurrently written
1447abe96eddelphij   file, reseting and retrying on end-of-file, when size is not 1.
1450354ebf4delphijZEXTERN int ZEXPORT gzwrite OF((gzFile file,
1451354ebf4delphij                                voidpc buf, unsigned len));
145370c83c0peter     Writes the given number of uncompressed bytes into the compressed file.
1454354ebf4delphij   gzwrite returns the number of uncompressed bytes written or 0 in case of
1455354ebf4delphij   error.
1458abe96eddelphijZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
1459abe96eddelphij                                      z_size_t nitems, gzFile file));
1461abe96eddelphij     gzfwrite() writes nitems items of size size from buf to file, duplicating
1462abe96eddelphij   the interface of stdio's fwrite(), with size_t request and return types.  If
1463abe96eddelphij   the library defines size_t, then z_size_t is identical to size_t.  If not,
1464abe96eddelphij   then z_size_t is an unsigned integer type that can contain a pointer.
1466abe96eddelphij     gzfwrite() returns the number of full items written of size size, or zero
1467abe96eddelphij   if there was an error.  If the multiplication of size and nitems overflows,
1468abe96eddelphij   i.e. the product does not fit in a z_size_t, then nothing is written, zero
1469abe96eddelphij   is returned, and the error state is set to Z_STREAM_ERROR.
1472abe1867delphijZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
1474354ebf4delphij     Converts, formats, and writes the arguments to the compressed file under
1475354ebf4delphij   control of the format string, as in fprintf.  gzprintf returns the number of
1476abe96eddelphij   uncompressed bytes actually written, or a negative zlib error code in case
1477abe96eddelphij   of error.  The number of uncompressed bytes written is limited to 8191, or
1478abe96eddelphij   one less than the buffer size given to gzbuffer().  The caller should assure
1479abe96eddelphij   that this limit is not exceeded.  If it is exceeded, then gzprintf() will
1480abe96eddelphij   return an error (0) with nothing written.  In this case, there may also be a
1481abe96eddelphij   buffer overflow with unpredictable consequences, which is possible only if
1482abe96eddelphij   zlib was compiled with the insecure functions sprintf() or vsprintf()
1483abe96eddelphij   because the secure snprintf() or vsnprintf() functions were not available.
1484abe96eddelphij   This can be determined using zlibCompileFlags().
1487b66130epeterZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1489354ebf4delphij     Writes the given null-terminated string to the compressed file, excluding
14909f86c0bsteve   the terminating null character.
1492354ebf4delphij     gzputs returns the number of characters written, or -1 in case of error.
1495b66130epeterZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1497354ebf4delphij     Reads bytes from the compressed file until len-1 characters are read, or a
1498354ebf4delphij   newline character is read and transferred to buf, or an end-of-file
1499354ebf4delphij   condition is encountered.  If any characters are read or if len == 1, the
1500354ebf4delphij   string is terminated with a null character.  If no characters are read due
1501354ebf4delphij   to an end-of-file or len < 1, then the buffer is left untouched.
1503354ebf4delphij     gzgets returns buf which is a null-terminated string, or it returns NULL
1504354ebf4delphij   for end-of-file or in case of error.  If there was an error, the contents at
1505354ebf4delphij   buf are indeterminate.
1508354ebf4delphijZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
1510354ebf4delphij     Writes c, converted to an unsigned char, into the compressed file.  gzputc
1511354ebf4delphij   returns the value that was written, or -1 in case of error.
1514354ebf4delphijZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1516354ebf4delphij     Reads one byte from the compressed file.  gzgetc returns this byte or -1
1517abe1867delphij   in case of end of file or error.  This is implemented as a macro for speed.
1518abe1867delphij   As such, it does not do all of the checking the other functions do.  I.e.
1519abe1867delphij   it does not check to see if file is NULL, nor whether the structure file
1520abe1867delphij   points to has been clobbered or not.
1523354ebf4delphijZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
1525354ebf4delphij     Push one character back onto the stream to be read as the first character
1526354ebf4delphij   on the next read.  At least one character of push-back is allowed.
1527354ebf4delphij   gzungetc() returns the character pushed, or -1 on failure.  gzungetc() will
1528354ebf4delphij   fail if c is -1, and may fail if a character has been pushed but not read
1529354ebf4delphij   yet.  If gzungetc is used immediately after gzopen or gzdopen, at least the
1530354ebf4delphij   output buffer size of pushed characters is allowed.  (See gzbuffer above.)
1531354ebf4delphij   The pushed character will be discarded if the stream is repositioned with
1532354ebf4delphij   gzseek() or gzrewind().
1535354ebf4delphijZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
1537354ebf4delphij     Flushes all pending output into the compressed file.  The parameter flush
1538354ebf4delphij   is as in the deflate() function.  The return value is the zlib error number
1539354ebf4delphij   (see function gzerror below).  gzflush is only permitted when writing.
1541354ebf4delphij     If the flush parameter is Z_FINISH, the remaining data is written and the
1542354ebf4delphij   gzip stream is completed in the output.  If gzwrite() is called again, a new
1543354ebf4delphij   gzip stream will be started in the output.  gzread() is able to read such
1544abe96eddelphij   concatenated gzip streams.
1546354ebf4delphij     gzflush should be called only when strictly necessary because it will
1547354ebf4delphij   degrade compression if called too often.
1551354ebf4delphijZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
1552354ebf4delphij                                   z_off_t offset, int whence));
1554354ebf4delphij     Sets the starting position for the next gzread or gzwrite on the given
1555354ebf4delphij   compressed file.  The offset represents a number of bytes in the
1556354ebf4delphij   uncompressed data stream.  The whence parameter is defined as in lseek(2);
15579f86c0bsteve   the value SEEK_END is not supported.
15599f86c0bsteve     If the file is opened for reading, this function is emulated but can be
1560354ebf4delphij   extremely slow.  If the file is opened for writing, only forward seeks are
15619f86c0bsteve   supported; gzseek then compresses a sequence of zeroes up to the new
15629f86c0bsteve   starting position.
1564354ebf4delphij     gzseek returns the resulting offset location as measured in bytes from
15659f86c0bsteve   the beginning of the uncompressed stream, or -1 in case of error, in
15669f86c0bsteve   particular if the file is opened for writing and the new starting position
15679f86c0bsteve   would be before the current position.
1570b66130epeterZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
15729f86c0bsteve     Rewinds the given file. This function is supported only for reading.
1574354ebf4delphij     gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1578b66130epeterZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
1580354ebf4delphij     Returns the starting position for the next gzread or gzwrite on the given
1581354ebf4delphij   compressed file.  This position represents a number of bytes in the
1582354ebf4delphij   uncompressed data stream, and is zero when starting, even if appending or
1583354ebf4delphij   reading a gzip stream from the middle of a file using gzdopen().
1585354ebf4delphij     gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1589354ebf4delphijZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
1591354ebf4delphij     Returns the current offset in the file being read or written.  This offset
1592354ebf4delphij   includes the count of bytes that precede the gzip stream, for example when
1593354ebf4delphij   appending or when using gzdopen() for reading.  When reading, the offset
1594354ebf4delphij   does not include as yet unused buffered input.  This information can be used
1595354ebf4delphij   for a progress indicator.  On error, gzoffset() returns -1.
1598b66130epeterZEXTERN int ZEXPORT gzeof OF((gzFile file));
1600354ebf4delphij     Returns true (1) if the end-of-file indicator has been set while reading,
1601354ebf4delphij   false (0) otherwise.  Note that the end-of-file indicator is set only if the
1602354ebf4delphij   read tried to go past the end of the input, but came up short.  Therefore,
1603354ebf4delphij   just like feof(), gzeof() may return false even if there is no more data to
1604354ebf4delphij   read, in the event that the last read request was for the exact number of
1605354ebf4delphij   bytes remaining in the input file.  This will happen if the input file size
1606354ebf4delphij   is an exact multiple of the buffer size.
1608354ebf4delphij     If gzeof() returns true, then the read functions will return no more data,
1609354ebf4delphij   unless the end-of-file indicator is reset by gzclearerr() and the input file
1610354ebf4delphij   has grown since the previous end of file was detected.
1613caf24dddesZEXTERN int ZEXPORT gzdirect OF((gzFile file));
1615354ebf4delphij     Returns true (1) if file is being copied directly while reading, or false
1616abe1867delphij   (0) if file is a gzip stream being decompressed.
1618354ebf4delphij     If the input file is empty, gzdirect() will return true, since the input
1619354ebf4delphij   does not contain a gzip stream.
1621354ebf4delphij     If gzdirect() is used immediately after gzopen() or gzdopen() it will
1622354ebf4delphij   cause buffers to be allocated to allow reading the file to determine if it
1623354ebf4delphij   is a gzip file.  Therefore if gzbuffer() is used, it should be called before
1624354ebf4delphij   gzdirect().
1626abe1867delphij     When writing, gzdirect() returns true (1) if transparent writing was
1627abe1867delphij   requested ("wT" for the gzopen() mode), or false (0) otherwise.  (Note:
1628abe1867delphij   gzdirect() is not needed when writing.  Transparent writing must be
1629abe1867delphij   explicitly requested, so the application already knows the answer.  When
1630abe1867delphij   linking statically, using gzdirect() will include all of the zlib code for
1631abe1867delphij   gzip file reading and decompression, which may not be desired.)
1634b66130epeterZEXTERN int ZEXPORT    gzclose OF((gzFile file));
1636354ebf4delphij     Flushes all pending output if necessary, closes the compressed file and
1637354ebf4delphij   deallocates the (de)compression state.  Note that once file is closed, you
1638354ebf4delphij   cannot call gzerror with file, since its structures have been deallocated.
1639354ebf4delphij   gzclose must not be called more than once on the same file, just as free
1640354ebf4delphij   must not be called more than once on the same allocation.
1642354ebf4delphij     gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1643abe1867delphij   file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1644abe1867delphij   last read ended in the middle of a gzip stream, or Z_OK on success.
1647354ebf4delphijZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
1648354ebf4delphijZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
1650354ebf4delphij     Same as gzclose(), but gzclose_r() is only for use when reading, and
1651354ebf4delphij   gzclose_w() is only for use when writing or appending.  The advantage to
1652354ebf4delphij   using these instead of gzclose() is that they avoid linking in zlib
1653354ebf4delphij   compression or decompression code that is not used when only reading or only
1654354ebf4delphij   writing respectively.  If gzclose() is used, then both compression and
1655354ebf4delphij   decompression code will be included the application when linking to a static
1656354ebf4delphij   zlib library.
1659b66130epeterZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1661354ebf4delphij     Returns the error message for the last error which occurred on the given
1662354ebf4delphij   compressed file.  errnum is set to zlib error number.  If an error occurred
1663354ebf4delphij   in the file system and not in the compression library, errnum is set to
1664354ebf4delphij   Z_ERRNO and the application may consult errno to get the exact error code.
1666354ebf4delphij     The application must not modify the returned string.  Future calls to
1667354ebf4delphij   this function may invalidate the previously returned string.  If file is
1668354ebf4delphij   closed, then the string previously returned by gzerror will no longer be
1669354ebf4delphij   available.
1671354ebf4delphij     gzerror() should be used to distinguish errors from end-of-file for those
1672354ebf4delphij   functions above that do not distinguish those cases in their return values.
1675439ed8dtjrZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1677354ebf4delphij     Clears the error and end-of-file flags for file.  This is analogous to the
1678354ebf4delphij   clearerr() function in stdio.  This is useful for continuing to read a gzip
1679439ed8dtjr   file that is being written concurrently.
1682abe1867delphij#endif /* !Z_SOLO */
168470c83c0peter                        /* checksum functions */
168770c83c0peter     These functions are not related to compression but are exported
1688354ebf4delphij   anyway because they might be useful in applications using the compression
1689354ebf4delphij   library.
1692b66130epeterZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
169470c83c0peter     Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1695354ebf4delphij   return the updated checksum.  If buf is Z_NULL, this function returns the
1696354ebf4delphij   required initial value for the checksum.
1698abe96eddelphij     An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1699354ebf4delphij   much faster.
1701354ebf4delphij   Usage example:
170370c83c0peter     uLong adler = adler32(0L, Z_NULL, 0);
170570c83c0peter     while (read_buffer(buffer, length) != EOF) {
170670c83c0peter       adler = adler32(adler, buffer, length);
170770c83c0peter     }
170870c83c0peter     if (adler != original_adler) error();
1711abe96eddelphijZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf,
1712abe96eddelphij                                    z_size_t len));
1714abe96eddelphij     Same as adler32(), but with a size_t length.
1718caf24dddesZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
1719caf24dddes                                          z_off_t len2));
1721caf24dddes     Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
1722caf24dddes   and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1723caf24dddes   each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
1724abe1867delphij   seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.  Note
1725abe1867delphij   that the z_off_t type (like off_t) is a signed integer.  If len2 is
1726abe1867delphij   negative, the result has no meaning or utility.
1729b66130epeterZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
1731caf24dddes     Update a running CRC-32 with the bytes buf[0..len-1] and return the
1732354ebf4delphij   updated CRC-32.  If buf is Z_NULL, this function returns the required
17335ecec51delphij   initial value for the crc.  Pre- and post-conditioning (one's complement) is
17345ecec51delphij   performed within this function so it shouldn't be done by the application.
173670c83c0peter   Usage example:
173870c83c0peter     uLong crc = crc32(0L, Z_NULL, 0);
174070c83c0peter     while (read_buffer(buffer, length) != EOF) {
174170c83c0peter       crc = crc32(crc, buffer, length);
174270c83c0peter     }
174370c83c0peter     if (crc != original_crc) error();
1746abe96eddelphijZEXTERN uLong ZEXPORT crc32_z OF((uLong adler, const Bytef *buf,
1747abe96eddelphij                                  z_size_t len));
1749abe96eddelphij     Same as crc32(), but with a size_t length.
1753caf24dddesZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
1755caf24dddes     Combine two CRC-32 check values into one.  For two sequences of bytes,
1756caf24dddes   seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1757caf24dddes   calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
1758caf24dddes   check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1759caf24dddes   len2.
176370c83c0peter                        /* various hacks, don't look :) */
176570c83c0peter/* deflateInit and inflateInit are macros to allow checking the zlib version
176670c83c0peter * and the compiler's view of z_stream:
176770c83c0peter */
1768b66130epeterZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1769b66130epeter                                     const char *version, int stream_size));
1770b66130epeterZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
17719f86c0bsteve                                     const char *version, int stream_size));
1772b66130epeterZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
1773b66130epeter                                      int windowBits, int memLevel,
1774b66130epeter                                      int strategy, const char *version,
1775b66130epeter                                      int stream_size));
1776b66130epeterZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
1777b66130epeter                                      const char *version, int stream_size));
1778caf24dddesZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
1779439ed8dtjr                                         unsigned char FAR *window,
1780439ed8dtjr                                         const char *version,
1781439ed8dtjr                                         int stream_size));
1782abe96eddelphij#ifdef Z_PREFIX_SET
1783abe96eddelphij#  define z_deflateInit(strm, level) \
1784abe96eddelphij          deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1785abe96eddelphij#  define z_inflateInit(strm) \
1786abe96eddelphij          inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1787abe96eddelphij#  define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1788abe96eddelphij          deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1789abe96eddelphij                        (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1790abe96eddelphij#  define z_inflateInit2(strm, windowBits) \
1791abe96eddelphij          inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1792abe96eddelphij                        (int)sizeof(z_stream))
1793abe96eddelphij#  define z_inflateBackInit(strm, windowBits, window) \
1794abe96eddelphij          inflateBackInit_((strm), (windowBits), (window), \
1795abe96eddelphij                           ZLIB_VERSION, (int)sizeof(z_stream))
1797abe96eddelphij#  define deflateInit(strm, level) \
1798abe96eddelphij          deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
1799abe96eddelphij#  define inflateInit(strm) \
1800abe96eddelphij          inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
1801abe96eddelphij#  define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1802abe96eddelphij          deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1803abe96eddelphij                        (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
1804abe96eddelphij#  define inflateInit2(strm, windowBits) \
1805abe96eddelphij          inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
1806abe96eddelphij                        (int)sizeof(z_stream))
1807abe96eddelphij#  define inflateBackInit(strm, windowBits, window) \
1808abe96eddelphij          inflateBackInit_((strm), (windowBits), (window), \
1809abe96eddelphij                           ZLIB_VERSION, (int)sizeof(z_stream))
1812abe1867delphij#ifndef Z_SOLO
1814abe1867delphij/* gzgetc() macro and its supporting function and exposed data structure.  Note
1815abe1867delphij * that the real internal state is much larger than the exposed structure.
1816abe1867delphij * This abbreviated structure exposes just enough for the gzgetc() macro.  The
1817abe1867delphij * user should not mess with these exposed elements, since their names or
1818abe1867delphij * behavior could change in the future, perhaps even capriciously.  They can
1819abe1867delphij * only be used by the gzgetc() macro.  You have been warned.
1820abe1867delphij */
1821abe1867delphijstruct gzFile_s {
1822abe1867delphij    unsigned have;
1823abe1867delphij    unsigned char *next;
1824abe1867delphij    z_off64_t pos;
18265ecec51delphijZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
18275ecec51delphij#ifdef Z_PREFIX_SET
18285ecec51delphij#  undef z_gzgetc
18295ecec51delphij#  define z_gzgetc(g) \
1830abe96eddelphij          ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
18325ecec51delphij#  define gzgetc(g) \
1833abe96eddelphij          ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
18363799ed4delphij/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
18373799ed4delphij * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
18383799ed4delphij * both are true, the application gets the *64 functions, and the regular
18393799ed4delphij * functions are changed to 64 bits) -- in case these are set on systems
18403799ed4delphij * without large file support, _LFS64_LARGEFILE must also be true
18413799ed4delphij */
18425ecec51delphij#ifdef Z_LARGE64
1843354ebf4delphij   ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
18443799ed4delphij   ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
18453799ed4delphij   ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
18463799ed4delphij   ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
18473799ed4delphij   ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
18483799ed4delphij   ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
18515ecec51delphij#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
1852abe1867delphij#  ifdef Z_PREFIX_SET
1853abe1867delphij#    define z_gzopen z_gzopen64
1854abe1867delphij#    define z_gzseek z_gzseek64
1855abe1867delphij#    define z_gztell z_gztell64
1856abe1867delphij#    define z_gzoffset z_gzoffset64
1857abe1867delphij#    define z_adler32_combine z_adler32_combine64
1858abe1867delphij#    define z_crc32_combine z_crc32_combine64
1859abe1867delphij#  else
1860abe1867delphij#    define gzopen gzopen64
1861abe1867delphij#    define gzseek gzseek64
1862abe1867delphij#    define gztell gztell64
1863abe1867delphij#    define gzoffset gzoffset64
1864abe1867delphij#    define adler32_combine adler32_combine64
1865abe1867delphij#    define crc32_combine crc32_combine64
1866abe1867delphij#  endif
18675ecec51delphij#  ifndef Z_LARGE64
1868354ebf4delphij     ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
18693799ed4delphij     ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
18703799ed4delphij     ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
18713799ed4delphij     ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
18723799ed4delphij     ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
18733799ed4delphij     ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
1874354ebf4delphij#  endif
1876354ebf4delphij   ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
1877354ebf4delphij   ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
1878354ebf4delphij   ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
1879354ebf4delphij   ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
1880354ebf4delphij   ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1881354ebf4delphij   ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1884abe1867delphij#else /* Z_SOLO */
1886abe1867delphij   ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
1887abe1867delphij   ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
1889abe1867delphij#endif /* !Z_SOLO */
18913799ed4delphij/* undocumented functions */
1892dcdd797kientzleZEXTERN const char   * ZEXPORT zError           OF((int));
1893354ebf4delphijZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp));
18945ecec51delphijZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table    OF((void));
1895354ebf4delphijZEXTERN int            ZEXPORT inflateUndermine OF((z_streamp, int));
1896abe96eddelphijZEXTERN int            ZEXPORT inflateValidate OF((z_streamp, int));
1897abe96eddelphijZEXTERN unsigned long  ZEXPORT inflateCodesUsed OF ((z_streamp));
1898abe1867delphijZEXTERN int            ZEXPORT inflateResetKeep OF((z_streamp));
1899abe1867delphijZEXTERN int            ZEXPORT deflateResetKeep OF((z_streamp));
1900abe96eddelphij#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
19015ecec51delphijZEXTERN gzFile         ZEXPORT gzopen_w OF((const wchar_t *path,
19025ecec51delphij                                            const char *mode));
19043aa8c3cdelphij#if defined(STDC) || defined(Z_HAVE_STDARG_H)
19053aa8c3cdelphij#  ifndef Z_SOLO
19063aa8c3cdelphijZEXTERN int            ZEXPORTVA gzvprintf Z_ARG((gzFile file,
19073aa8c3cdelphij                                                  const char *format,
19083aa8c3cdelphij                                                  va_list va));
19093aa8c3cdelphij#  endif
191270c83c0peter#ifdef __cplusplus
1916439ed8dtjr#endif /* ZLIB_H */