hedgewars: comparison misc/libfreetype/src/gzip/zlib.h

equal deleted inserted replaced

-:f9283dc4860d
+:88f2e05288ba
+/* zlib.h -- interface of the 'zlib' general purpose compression library
+version 1.1.4, March 11th, 2002
+Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+1. The origin of this software must not be misrepresented; you must not
+claim that you wrote the original software. If you use this software
+in a product, an acknowledgment in the product documentation would be
+appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+Jean-loup Gailly        Mark Adler
+jloup@gzip.org          madler@alumni.caltech.edu
+The data format used by the zlib library is described by RFCs (Request for
+Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
+(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
+*/
+#ifndef _ZLIB_H
+#define _ZLIB_H
+#include "zconf.h"
+#ifdef __cplusplus
+extern "C" {
+#endif
+#define ZLIB_VERSION "1.1.4"
+/*
+The 'zlib' compression library provides in-memory compression and
+decompression functions, including integrity checks of the uncompressed
+data.  This version of the library supports only one compression method
+(deflation) but other algorithms will be added later and will have the same
+stream interface.
+Compression can be done in a single step if the buffers are large
+enough (for example if an input file is mmap'ed), or can be done by
+repeated calls of the compression function.  In the latter case, the
+application must provide more input and/or consume the output
+(providing more output space) before each call.
+The library also supports reading and writing files in gzip (.gz) format
+with an interface similar to that of stdio.
+The library does not install any signal handler. The decoder checks
+the consistency of the compressed data, so the library should never
+crash even in case of corrupted input.
+*/
+typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
+typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
+struct internal_state;
+typedef struct z_stream_s {
+Bytef    *next_in;  /* next input byte */
+uInt     avail_in;  /* number of bytes available at next_in */
+uLong    total_in;  /* total nb of input bytes read so far */
+Bytef    *next_out; /* next output byte should be put there */
+uInt     avail_out; /* remaining free space at next_out */
+uLong    total_out; /* total nb of bytes output so far */
+char     *msg;      /* last error message, NULL if no error */
+struct internal_state FAR *state; /* not visible by applications */
+alloc_func zalloc;  /* used to allocate the internal state */
+free_func  zfree;   /* used to free the internal state */
+voidpf     opaque;  /* private data object passed to zalloc and zfree */
+int     data_type;  /* best guess about the data type: ascii or binary */
+uLong   adler;      /* adler32 value of the uncompressed data */
+uLong   reserved;   /* reserved for future use */
+} z_stream;
+typedef z_stream FAR *z_streamp;
+/*
+The application must update next_in and avail_in when avail_in has
+dropped to zero. It must update next_out and avail_out when avail_out
+has dropped to zero. The application must initialize zalloc, zfree and
+opaque before calling the init function. All other fields are set by the
+compression library and must not be updated by the application.
+The opaque value provided by the application will be passed as the first
+parameter for calls of zalloc and zfree. This can be useful for custom
+memory management. The compression library attaches no meaning to the
+opaque value.
+zalloc must return Z_NULL if there is not enough memory for the object.
+If zlib is used in a multi-threaded application, zalloc and zfree must be
+thread safe.
+On 16-bit systems, the functions zalloc and zfree must be able to allocate
+exactly 65536 bytes, but will not be required to allocate more than this
+if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
+pointers returned by zalloc for objects of exactly 65536 bytes *must*
+have their offset normalized to zero. The default allocation function
+provided by this library ensures this (see zutil.c). To reduce memory
+requirements and avoid any allocation of 64K objects, at the expense of
+compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
+The fields total_in and total_out can be used for statistics or
+progress reports. After compression, total_in holds the total size of
+the uncompressed data and may be saved for use in the decompressor
+(particularly if the decompressor wants to decompress everything in
+a single step).
+*/
+/* constants */
+#define Z_NO_FLUSH      0
+#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
+#define Z_SYNC_FLUSH    2
+#define Z_FULL_FLUSH    3
+#define Z_FINISH        4
+/* Allowed flush values; see deflate() below for details */
+#define Z_OK            0
+#define Z_STREAM_END    1
+#define Z_NEED_DICT     2
+#define Z_ERRNO        (-1)
+#define Z_STREAM_ERROR (-2)
+#define Z_DATA_ERROR   (-3)
+#define Z_MEM_ERROR    (-4)
+#define Z_BUF_ERROR    (-5)
+#define Z_VERSION_ERROR (-6)
+/* Return codes for the compression/decompression functions. Negative
+* values are errors, positive values are used for special but normal events.
+*/
+#define Z_NO_COMPRESSION         0
+#define Z_BEST_SPEED             1
+#define Z_BEST_COMPRESSION       9
+#define Z_DEFAULT_COMPRESSION  (-1)
+/* compression levels */
+#define Z_FILTERED            1
+#define Z_HUFFMAN_ONLY        2
+#define Z_DEFAULT_STRATEGY    0
+/* compression strategy; see deflateInit2() below for details */
+#define Z_BINARY   0
+#define Z_ASCII    1
+#define Z_UNKNOWN  2
+/* Possible values of the data_type field */
+#define Z_DEFLATED   8
+/* The deflate compression method (the only one supported in this version) */
+#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
+/* basic functions */
+/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
+If the first character differs, the library code actually used is
+not compatible with the zlib.h header file used by the application.
+This check is automatically made by deflateInit and inflateInit.
+*/
+/*
+ZEXTERN(int)  deflateInit OF((z_streamp strm, int level));
+Initializes the internal stream state for compression. The fields
+zalloc, zfree and opaque must be initialized before by the caller.
+If zalloc and zfree are set to Z_NULL, deflateInit updates them to
+use default allocation functions.
+The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
+1 gives best speed, 9 gives best compression, 0 gives no compression at
+all (the input data is simply copied a block at a time).
+Z_DEFAULT_COMPRESSION requests a default compromise between speed and
+compression (currently equivalent to level 6).
+deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
+enough memory, Z_STREAM_ERROR if level is not a valid compression level,
+Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
+with the version assumed by the caller (ZLIB_VERSION).
+msg is set to null if there is no error message.  deflateInit does not
+perform any compression: this will be done by deflate().
+*/
+/*
+deflate compresses as much data as possible, and stops when the input
+buffer becomes empty or the output buffer becomes full. It may introduce some
+output latency (reading input without producing any output) except when
+forced to flush.
+The detailed semantics are as follows. deflate performs one or both of the
+following actions:
+- Compress more input starting at next_in and update next_in and avail_in
+accordingly. If not all input can be processed (because there is not
+enough room in the output buffer), next_in and avail_in are updated and
+processing will resume at this point for the next call of deflate().
+- Provide more output starting at next_out and update next_out and avail_out
+accordingly. This action is forced if the parameter flush is non zero.
+Forcing flush frequently degrades the compression ratio, so this parameter
+should be set only when necessary (in interactive applications).
+Some output may be provided even if flush is not set.
+Before the call of deflate(), the application should ensure that at least
+one of the actions is possible, by providing more input and/or consuming
+more output, and updating avail_in or avail_out accordingly; avail_out
+should never be zero before the call. The application can consume the
+compressed output when it wants, for example when the output buffer is full
+(avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
+and with zero avail_out, it must be called again after making room in the
+output buffer because there might be more output pending.
+If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
+flushed to the output buffer and the output is aligned on a byte boundary, so
+that the decompressor can get all input data available so far. (In particular
+avail_in is zero after the call if enough output space has been provided
+before the call.)  Flushing may degrade compression for some compression
+algorithms and so it should be used only when necessary.
+If flush is set to Z_FULL_FLUSH, all output is flushed as with
+Z_SYNC_FLUSH, and the compression state is reset so that decompression can
+restart from this point if previous compressed data has been damaged or if
+random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
+the compression.
+If deflate returns with avail_out == 0, this function must be called again
+with the same value of the flush parameter and more output space (updated
+avail_out), until the flush is complete (deflate returns with non-zero
+avail_out).
+If the parameter flush is set to Z_FINISH, pending input is processed,
+pending output is flushed and deflate returns with Z_STREAM_END if there
+was enough output space; if deflate returns with Z_OK, this function must be
+called again with Z_FINISH and more output space (updated avail_out) but no
+more input data, until it returns with Z_STREAM_END or an error. After
+deflate has returned Z_STREAM_END, the only possible operations on the
+stream are deflateReset or deflateEnd.
+Z_FINISH can be used immediately after deflateInit if all the compression
+is to be done in a single step. In this case, avail_out must be at least
+0.1% larger than avail_in plus 12 bytes.  If deflate does not return
+Z_STREAM_END, then it must be called again as described above.
+deflate() sets strm->adler to the adler32 checksum of all input read
+so far (that is, total_in bytes).
+deflate() may update data_type if it can make a good guess about
+the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
+binary. This field is only for information purposes and does not affect
+the compression algorithm in any manner.
+deflate() returns Z_OK if some progress has been made (more input
+processed or more output produced), Z_STREAM_END if all input has been
+consumed and all output has been produced (only when flush is set to
+Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
+if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
+(for example avail_in or avail_out was zero).
+*/
+/*
+All dynamically allocated data structures for this stream are freed.
+This function discards any unprocessed input and does not flush any
+pending output.
+deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
+stream state was inconsistent, Z_DATA_ERROR if the stream was freed
+prematurely (some input or output was discarded). In the error case,
+msg may be set but then points to a static string (which must not be
+deallocated).
+*/
+/*
+ZEXTERN(int)  inflateInit OF((z_streamp strm));
+Initializes the internal stream state for decompression. The fields
+next_in, avail_in, zalloc, zfree and opaque must be initialized before by
+the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
+value depends on the compression method), inflateInit determines the
+compression method from the zlib header and allocates all data structures
+accordingly; otherwise the allocation will be deferred to the first call of
+inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
+use default allocation functions.
+inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
+memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
+version assumed by the caller.  msg is set to null if there is no error
+message. inflateInit does not perform any decompression apart from reading
+the zlib header if present: this will be done by inflate().  (So next_in and
+avail_in may be modified, but next_out and avail_out are unchanged.)
+*/
+ZEXTERN(int) inflate OF((z_streamp strm, int flush));
+/*
+inflate decompresses as much data as possible, and stops when the input
+buffer becomes empty or the output buffer becomes full. It may some
+introduce some output latency (reading input without producing any output)
+except when forced to flush.
+The detailed semantics are as follows. inflate performs one or both of the
+following actions:
+- Decompress more input starting at next_in and update next_in and avail_in
+accordingly. If not all input can be processed (because there is not
+enough room in the output buffer), next_in is updated and processing
+will resume at this point for the next call of inflate().
+- Provide more output starting at next_out and update next_out and avail_out
+accordingly.  inflate() provides as much output as possible, until there
+is no more input data or no more space in the output buffer (see below
+about the flush parameter).
+Before the call of inflate(), the application should ensure that at least
+one of the actions is possible, by providing more input and/or consuming
+more output, and updating the next_* and avail_* values accordingly.
+The application can consume the uncompressed output when it wants, for
+example when the output buffer is full (avail_out == 0), or after each
+call of inflate(). If inflate returns Z_OK and with zero avail_out, it
+must be called again after making room in the output buffer because there
+might be more output pending.
+If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
+output as possible to the output buffer. The flushing behavior of inflate is
+not specified for values of the flush parameter other than Z_SYNC_FLUSH
+and Z_FINISH, but the current implementation actually flushes as much output
+as possible anyway.
+inflate() should normally be called until it returns Z_STREAM_END or an
+error. However if all decompression is to be performed in a single step
+(a single call of inflate), the parameter flush should be set to
+Z_FINISH. In this case all pending input is processed and all pending
+output is flushed; avail_out must be large enough to hold all the
+uncompressed data. (The size of the uncompressed data may have been saved
+by the compressor for this purpose.) The next operation on this stream must
+be inflateEnd to deallocate the decompression state. The use of Z_FINISH
+is never required, but can be used to inform inflate that a faster routine
+may be used for the single inflate() call.
+If a preset dictionary is needed at this point (see inflateSetDictionary
+below), inflate sets strm-adler to the adler32 checksum of the
+dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
+it sets strm->adler to the adler32 checksum of all output produced
+so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
+an error code as described below. At the end of the stream, inflate()
+checks that its computed adler32 checksum is equal to that saved by the
+compressor and returns Z_STREAM_END only if the checksum is correct.
+inflate() returns Z_OK if some progress has been made (more input processed
+or more output produced), Z_STREAM_END if the end of the compressed data has
+been reached and all uncompressed output has been produced, Z_NEED_DICT if a
+preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
+corrupted (input stream not conforming to the zlib format or incorrect
+adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
+(for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
+enough memory, Z_BUF_ERROR if no progress is possible or if there was not
+enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
+case, the application may then call inflateSync to look for a good
+compression block.
+*/
+ZEXTERN(int)  inflateEnd OF((z_streamp strm));
+/*
+All dynamically allocated data structures for this stream are freed.
+This function discards any unprocessed input and does not flush any
+pending output.
+inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
+was inconsistent. In the error case, msg may be set but then points to a
+static string (which must not be deallocated).
+*/
+/* Advanced functions */
+/*
+The following functions are needed only in some special applications.
+*/
+/*
+ZEXTERN(int)  deflateInit2 OF((z_streamp strm,
+int  level,
+int  method,
+int  windowBits,
+int  memLevel,
+int  strategy));
+This is another version of deflateInit with more compression options. The
+fields next_in, zalloc, zfree and opaque must be initialized before by
+the caller.
+The method parameter is the compression method. It must be Z_DEFLATED in
+this version of the library.
+The windowBits parameter is the base two logarithm of the window size
+(the size of the history buffer).  It should be in the range 8..15 for this
+version of the library. Larger values of this parameter result in better
+compression at the expense of memory usage. The default value is 15 if
+deflateInit is used instead.
+The memLevel parameter specifies how much memory should be allocated
+for the internal compression state. memLevel=1 uses minimum memory but
+is slow and reduces compression ratio; memLevel=9 uses maximum memory
+for optimal speed. The default value is 8. See zconf.h for total memory
+usage as a function of windowBits and memLevel.
+The strategy parameter is used to tune the compression algorithm. Use the
+value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
+filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
+string match).  Filtered data consists mostly of small values with a
+somewhat random distribution. In this case, the compression algorithm is
+tuned to compress them better. The effect of Z_FILTERED is to force more
+Huffman coding and less string matching; it is somewhat intermediate
+between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
+the compression ratio but not the correctness of the compressed output even
+if it is not set appropriately.
+deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
+memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
+method). msg is set to null if there is no error message.  deflateInit2 does
+not perform any compression: this will be done by deflate().
+*/
+/*
+Initializes the compression dictionary from the given byte sequence
+without producing any compressed output. This function must be called
+immediately after deflateInit, deflateInit2 or deflateReset, before any
+call of deflate. The compressor and decompressor must use exactly the same
+dictionary (see inflateSetDictionary).
+The dictionary should consist of strings (byte sequences) that are likely
+to be encountered later in the data to be compressed, with the most commonly
+used strings preferably put towards the end of the dictionary. Using a
+dictionary is most useful when the data to be compressed is short and can be
+predicted with good accuracy; the data can then be compressed better than
+with the default empty dictionary.
+Depending on the size of the compression data structures selected by
+deflateInit or deflateInit2, a part of the dictionary may in effect be
+discarded, for example if the dictionary is larger than the window size in
+deflate or deflate2. Thus the strings most likely to be useful should be
+put at the end of the dictionary, not at the front.
+Upon return of this function, strm->adler is set to the Adler32 value
+of the dictionary; the decompressor may later use this value to determine
+which dictionary has been used by the compressor. (The Adler32 value
+applies to the whole dictionary even if only a subset of the dictionary is
+actually used by the compressor.)
+deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
+parameter is invalid (such as NULL dictionary) or the stream state is
+inconsistent (for example if deflate has already been called for this stream
+or if the compression method is bsort). deflateSetDictionary does not
+perform any compression: this will be done by deflate().
+*/
+/*
+Sets the destination stream as a complete copy of the source stream.
+This function can be useful when several compression strategies will be
+tried, for example when there are several ways of pre-processing the input
+data with a filter. The streams that will be discarded should then be freed
+by calling deflateEnd.  Note that deflateCopy duplicates the internal
+compression state which can be quite large, so this strategy is slow and
+can consume lots of memory.
+deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
+enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
+(such as zalloc being NULL). msg is left unchanged in both source and
+destination.
+*/
+/*
+This function is equivalent to deflateEnd followed by deflateInit,
+but does not free and reallocate all the internal compression state.
+The stream will keep the same compression level and any other attributes
+that may have been set by deflateInit2.
+deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
+stream state was inconsistent (such as zalloc or state being NULL).
+*/
+/*
+Dynamically update the compression level and compression strategy.  The
+interpretation of level and strategy is as in deflateInit2.  This can be
+used to switch between compression and straight copy of the input data, or
+to switch to a different kind of input data requiring a different
+strategy. If the compression level is changed, the input available so far
+is compressed with the old level (and may be flushed); the new level will
+take effect only at the next call of deflate().
+Before the call of deflateParams, the stream state must be set as for
+a call of deflate(), since the currently available input may have to
+be compressed and flushed. In particular, strm->avail_out must be non-zero.
+deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
+stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
+if strm->avail_out was zero.
+*/
+/*
+ZEXTERN(int)  inflateInit2 OF((z_streamp strm,
+int  windowBits));
+This is another version of inflateInit with an extra parameter. The
+fields next_in, avail_in, zalloc, zfree and opaque must be initialized
+before by the caller.
+The windowBits parameter is the base two logarithm of the maximum window
+size (the size of the history buffer).  It should be in the range 8..15 for
+this version of the library. The default value is 15 if inflateInit is used
+instead. If a compressed stream with a larger window size is given as
+input, inflate() will return with the error code Z_DATA_ERROR instead of
+trying to allocate a larger window.
+inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
+memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
+memLevel). msg is set to null if there is no error message.  inflateInit2
+does not perform any decompression apart from reading the zlib header if
+present: this will be done by inflate(). (So next_in and avail_in may be
+modified, but next_out and avail_out are unchanged.)
+*/
+/*
+Initializes the decompression dictionary from the given uncompressed byte
+sequence. This function must be called immediately after a call of inflate
+if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
+can be determined from the Adler32 value returned by this call of
+inflate. The compressor and decompressor must use exactly the same
+dictionary (see deflateSetDictionary).
+inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
+parameter is invalid (such as NULL dictionary) or the stream state is
+inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
+expected one (incorrect Adler32 value). inflateSetDictionary does not
+perform any decompression: this will be done by subsequent calls of
+inflate().
+*/
+/*
+Skips invalid compressed data until a full flush point (see above the
+description of deflate with Z_FULL_FLUSH) can be found, or until all
+available input is skipped. No output is provided.
+inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
+if no more input was provided, Z_DATA_ERROR if no flush point has been found,
+or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
+case, the application may save the current current value of total_in which
+indicates where valid compressed data was found. In the error case, the
+application may repeatedly call inflateSync, providing more input each time,
+until success or end of the input data.
+*/
+ZEXTERN(int)  inflateReset OF((z_streamp strm));
+/*
+This function is equivalent to inflateEnd followed by inflateInit,
+but does not free and reallocate all the internal decompression state.
+The stream will keep attributes that may have been set by inflateInit2.
+inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
+stream state was inconsistent (such as zalloc or state being NULL).
+*/
+/* utility functions */
+/*
+The following utility functions are implemented on top of the
+basic stream-oriented functions. To simplify the interface, some
+default options are assumed (compression level and memory usage,
+standard memory allocation functions). The source code of these
+utility functions can easily be modified if you need special options.
+*/
+/*
+Compresses the source buffer into the destination buffer.  sourceLen is
+the byte length of the source buffer. Upon entry, destLen is the total
+size of the destination buffer, which must be at least 0.1% larger than
+sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
+compressed buffer.
+This function can be used to compress a whole file at once if the
+input file is mmap'ed.
+compress returns Z_OK if success, Z_MEM_ERROR if there was not
+enough memory, Z_BUF_ERROR if there was not enough room in the output
+buffer.
+*/
+/*
+Compresses the source buffer into the destination buffer. The level
+parameter has the same meaning as in deflateInit.  sourceLen is the byte
+length of the source buffer. Upon entry, destLen is the total size of the
+destination buffer, which must be at least 0.1% larger than sourceLen plus
+12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
+compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
+memory, Z_BUF_ERROR if there was not enough room in the output buffer,
+Z_STREAM_ERROR if the level parameter is invalid.
+*/
+/*
+Decompresses the source buffer into the destination buffer.  sourceLen is
+the byte length of the source buffer. Upon entry, destLen is the total
+size of the destination buffer, which must be large enough to hold the
+entire uncompressed data. (The size of the uncompressed data must have
+been saved previously by the compressor and transmitted to the decompressor
+by some mechanism outside the scope of this compression library.)
+Upon exit, destLen is the actual size of the compressed buffer.
+This function can be used to decompress a whole file at once if the
+input file is mmap'ed.
+uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
+enough memory, Z_BUF_ERROR if there was not enough room in the output
+buffer, or Z_DATA_ERROR if the input data was corrupted.
+*/
+/*
+Opens a gzip (.gz) file for reading or writing. The mode parameter
+is as in fopen ("rb" or "wb") but can also include a compression level
+("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
+Huffman only compression as in "wb1h". (See the description
+of deflateInit2 for more information about the strategy parameter.)
+gzopen can be used to read a file which is not in gzip format; in this
+case gzread will directly read from the file without decompression.
+gzopen returns NULL if the file could not be opened or if there was
+insufficient memory to allocate the (de)compression state; errno
+can be checked to distinguish the two cases (if errno is zero, the
+zlib error is Z_MEM_ERROR).  */
+/*
+gzdopen() associates a gzFile with the file descriptor fd.  File
+descriptors are obtained from calls like open, dup, creat, pipe or
+fileno (in the file has been previously opened with fopen).
+The mode parameter is as in gzopen.
+The next call of gzclose on the returned gzFile will also close the
+file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
+descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
+gzdopen returns NULL if there was insufficient memory to allocate
+the (de)compression state.
+*/
+/*
+Dynamically update the compression level or strategy. See the description
+of deflateInit2 for the meaning of these parameters.
+gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
+opened for writing.
+*/
+/*
+Reads the given number of uncompressed bytes from the compressed file.
+If the input file was not in gzip format, gzread copies the given number
+of bytes into the buffer.
+gzread returns the number of uncompressed bytes actually read (0 for
+end of file, -1 for error). */
+/*
+Writes the given number of uncompressed bytes into the compressed file.
+gzwrite returns the number of uncompressed bytes actually written
+(0 in case of error).
+*/
+/*
+Converts, formats, and writes the args to the compressed file under
+control of the format string, as in fprintf. gzprintf returns the number of
+uncompressed bytes actually written (0 in case of error).
+*/
+/*
+Writes the given null-terminated string to the compressed file, excluding
+the terminating null character.
+gzputs returns the number of characters written, or -1 in case of error.
+*/
+/*
+Reads bytes from the compressed file until len-1 characters are read, or
+a newline character is read and transferred to buf, or an end-of-file
+condition is encountered.  The string is then terminated with a null
+character.
+gzgets returns buf, or Z_NULL in case of error.
+*/
+/*
+Writes c, converted to an unsigned char, into the compressed file.
+gzputc returns the value that was written, or -1 in case of error.
+*/
+/*
+Reads one byte from the compressed file. gzgetc returns this byte
+or -1 in case of end of file or error.
+*/
+/*
+Flushes all pending output into the compressed file. The parameter
+flush is as in the deflate() function. The return value is the zlib
+error number (see function gzerror below). gzflush returns Z_OK if
+the flush parameter is Z_FINISH and all output could be flushed.
+gzflush should be called only when strictly necessary because it can
+degrade compression.
+*/
+/*
+Sets the starting position for the next gzread or gzwrite on the
+given compressed file. The offset represents a number of bytes in the
+uncompressed data stream. The whence parameter is defined as in lseek(2);
+the value SEEK_END is not supported.
+If the file is opened for reading, this function is emulated but can be
+extremely slow. If the file is opened for writing, only forward seeks are
+supported; gzseek then compresses a sequence of zeroes up to the new
+starting position.
+gzseek returns the resulting offset location as measured in bytes from
+the beginning of the uncompressed stream, or -1 in case of error, in
+particular if the file is opened for writing and the new starting position
+would be before the current position.
+*/
+/*
+Rewinds the given file. This function is supported only for reading.
+gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
+*/
+/*
+Returns the starting position for the next gzread or gzwrite on the
+given compressed file. This position represents a number of bytes in the
+uncompressed data stream.
+gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
+*/
+/*
+Returns 1 when EOF has previously been detected reading the given
+input stream, otherwise zero.
+*/
+/*
+Flushes all pending output if necessary, closes the compressed file
+and deallocates all the (de)compression state. The return value is the zlib
+error number (see function gzerror below).
+*/
+/*
+Returns the error message for the last error which occurred on the
+given compressed file. errnum is set to zlib error number. If an
+error occurred in the file system and not in the compression library,
+errnum is set to Z_ERRNO and the application may consult errno
+to get the exact error code.
+*/
+/* checksum functions */
+/*
+These functions are not related to compression but are exported
+anyway because they might be useful in applications using the
+compression library.
+*/
+ZEXTERN(uLong)  adler32 OF((uLong adler, const Bytef *buf, uInt len));
+/*
+Update a running Adler-32 checksum with the bytes buf[0..len-1] and
+return the updated checksum. If buf is NULL, this function returns
+the required initial value for the checksum.
+An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
+much faster. Usage example:
+uLong adler = adler32(0L, Z_NULL, 0);
+while (read_buffer(buffer, length) != EOF) {
+adler = adler32(adler, buffer, length);
+}
+if (adler != original_adler) error();
+*/
+/*
+Update a running crc with the bytes buf[0..len-1] and return the updated
+crc. If buf is NULL, this function returns the required initial value
+for the crc. Pre- and post-conditioning (one's complement) is performed
+within this function so it shouldn't be done by the application.
+Usage example:
+uLong crc = crc32(0L, Z_NULL, 0);
+while (read_buffer(buffer, length) != EOF) {
+crc = crc32(crc, buffer, length);
+}
+if (crc != original_crc) error();
+*/
+/* various hacks, don't look :) */
+/* deflateInit and inflateInit are macros to allow checking the zlib version
+* and the compiler's view of z_stream:
+*/
+ZEXTERN(int)  inflateInit2_ OF((z_streamp strm, int  windowBits,
+const char *version, int stream_size));
+#define deflateInit(strm, level) \
+deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
+#define inflateInit(strm) \
+inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
+#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
+deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
+(strategy),           ZLIB_VERSION, sizeof(z_stream))
+#define inflateInit2(strm, windowBits) \
+inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
+#ifdef __cplusplus
+}
+#endif
+#endif /* _ZLIB_H */