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+/* zlib.h -- interface of the 'zlib' general purpose compression library
+ version 1.2.8, April 28th, 2013
+
+ Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
+
+ This software is provided 'as-is', without any express or implied
+ warranty. In no event will the authors be held liable for any damages
+ arising from the use of this software.
+
+ Permission is granted to anyone to use this software for any purpose,
+ including commercial applications, and to alter it and redistribute it
+ freely, subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+ 2. Altered source versions must be plainly marked as such, and must not be
+ misrepresented as being the original software.
+ 3. This notice may not be removed or altered from any source distribution.
+
+ Jean-loup Gailly Mark Adler
+ jloup@gzip.org madler@alumni.caltech.edu
+
+
+ The data format used by the zlib library is described by RFCs (Request for
+ Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
+ (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
+*/
+
+#ifndef ZLIB_H
+#define ZLIB_H
+
+#include "zconf.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define ZLIB_VERSION "1.2.8"
+#define ZLIB_VERNUM 0x1280
+#define ZLIB_VER_MAJOR 1
+#define ZLIB_VER_MINOR 2
+#define ZLIB_VER_REVISION 8
+#define ZLIB_VER_SUBREVISION 0
+
+/*
+ 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,
+ or can be done by repeated calls of the compression function. In the latter
+ case, the application must provide more input and/or consume the output
+ (providing more output space) before each call.
+
+ The compressed data format used by default by the in-memory functions is
+ the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
+ around a deflate stream, which is itself documented in RFC 1951.
+
+ The library also supports reading and writing files in gzip (.gz) format
+ with an interface similar to that of stdio using the functions that start
+ with "gz". The gzip format is different from the zlib format. gzip is a
+ gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
+
+ This library can optionally read and write gzip streams in memory as well.
+
+ The zlib format was designed to be compact and fast for use in memory
+ and on communications channels. The gzip format was designed for single-
+ file compression on file systems, has a larger header than zlib to maintain
+ directory information, and uses a different, slower check method than zlib.
+
+ The library does not install any signal handler. The decoder checks
+ the consistency of the compressed data, so the library should never crash
+ even in case of corrupted input.
+*/
+
+typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
+typedef void (*free_func) OF((voidpf opaque, voidpf address));
+
+struct internal_state;
+
+typedef struct z_stream_s {
+ z_const Bytef *next_in; /* next input byte */
+ uInt avail_in; /* number of bytes available at next_in */
+ uLong total_in; /* total number 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 number of bytes output so far */
+
+ z_const char *msg; /* last error message, NULL if no error */
+ struct internal_state FAR *state; /* not visible by applications */
+
+ alloc_func zalloc; /* used to allocate the internal state */
+ free_func zfree; /* used to free the internal state */
+ voidpf opaque; /* private data object passed to zalloc and zfree */
+
+ int data_type; /* best guess about the data type: binary or text */
+ uLong adler; /* adler32 value of the uncompressed data */
+ uLong reserved; /* reserved for future use */
+} z_stream;
+
+typedef z_stream FAR *z_streamp;
+
+/*
+ gzip header information passed to and from zlib routines. See RFC 1952
+ for more details on the meanings of these fields.
+*/
+typedef struct gz_header_s {
+ int text; /* true if compressed data believed to be text */
+ uLong time; /* modification time */
+ int xflags; /* extra flags (not used when writing a gzip file) */
+ int os; /* operating system */
+ Bytef *extra; /* pointer to extra field or Z_NULL if none */
+ uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
+ uInt extra_max; /* space at extra (only when reading header) */
+ Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
+ uInt name_max; /* space at name (only when reading header) */
+ Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
+ uInt comm_max; /* space at comment (only when reading header) */
+ int hcrc; /* true if there was or will be a header crc */
+ int done; /* true when done reading gzip header (not used
+ when writing a gzip file) */
+} gz_header;
+
+typedef gz_header FAR *gz_headerp;
+
+/*
+ The application must update next_in and avail_in when avail_in has dropped
+ to zero. It must update next_out and avail_out when avail_out has dropped
+ to zero. The application must initialize zalloc, zfree and opaque before
+ calling the init function. All other fields are set by the compression
+ library and must not be updated by the application.
+
+ The opaque value provided by the application will be passed as the first
+ parameter for calls of zalloc and zfree. This can be useful for custom
+ memory management. The compression library attaches no meaning to the
+ opaque value.
+
+ zalloc must return Z_NULL if there is not enough memory for the object.
+ If zlib is used in a multi-threaded application, zalloc and zfree must be
+ thread safe.
+
+ On 16-bit systems, the functions zalloc and zfree must be able to allocate
+ exactly 65536 bytes, but will not be required to allocate more than this if
+ the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
+ returned by zalloc for objects of exactly 65536 bytes *must* have their
+ offset normalized to zero. The default allocation function provided by this
+ library ensures this (see zutil.c). To reduce memory requirements and avoid
+ any allocation of 64K objects, at the expense of compression ratio, compile
+ the library with -DMAX_WBITS=14 (see zconf.h).
+
+ The fields total_in and total_out can be used for statistics or progress
+ reports. After compression, total_in holds the total size of the
+ uncompressed data and may be saved for use in the decompressor (particularly
+ if the decompressor wants to decompress everything in a single step).
+*/
+
+ /* constants */
+
+#define Z_NO_FLUSH 0
+#define Z_PARTIAL_FLUSH 1
+#define Z_SYNC_FLUSH 2
+#define Z_FULL_FLUSH 3
+#define Z_FINISH 4
+#define Z_BLOCK 5
+#define Z_TREES 6
+/* Allowed flush values; see deflate() and inflate() below for details */
+
+#define Z_OK 0
+#define Z_STREAM_END 1
+#define Z_NEED_DICT 2
+#define Z_ERRNO (-1)
+#define Z_STREAM_ERROR (-2)
+#define Z_DATA_ERROR (-3)
+#define Z_MEM_ERROR (-4)
+#define Z_BUF_ERROR (-5)
+#define Z_VERSION_ERROR (-6)
+/* Return codes for the compression/decompression functions. Negative values
+ * are errors, positive values are used for special but normal events.
+ */
+
+#define Z_NO_COMPRESSION 0
+#define Z_BEST_SPEED 1
+#define Z_BEST_COMPRESSION 9
+#define Z_DEFAULT_COMPRESSION (-1)
+/* compression levels */
+
+#define Z_FILTERED 1
+#define Z_HUFFMAN_ONLY 2
+#define Z_RLE 3
+#define Z_FIXED 4
+#define Z_DEFAULT_STRATEGY 0
+/* compression strategy; see deflateInit2() below for details */
+
+#define Z_BINARY 0
+#define Z_TEXT 1
+#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
+#define Z_UNKNOWN 2
+/* Possible values of the data_type field (though see inflate()) */
+
+#define Z_DEFLATED 8
+/* The deflate compression method (the only one supported in this version) */
+
+#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
+
+#define zlib_version zlibVersion()
+/* for compatibility with versions < 1.0.2 */
+
+
+ /* basic functions */
+
+ZEXTERN const char * ZEXPORT zlibVersion OF((void));
+/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
+ If the first character differs, the library code actually used is not
+ compatible with the zlib.h header file used by the application. This check
+ is automatically made by deflateInit and inflateInit.
+ */
+
+/*
+ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
+
+ Initializes the internal stream state for compression. The fields
+ zalloc, zfree and opaque must be initialized before by the caller. If
+ zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
+ allocation functions.
+
+ The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
+ 1 gives best speed, 9 gives best compression, 0 gives no compression at all
+ (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
+ requests a default compromise between speed and compression (currently
+ equivalent to level 6).
+
+ deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
+ memory, Z_STREAM_ERROR if level is not a valid compression level, or
+ Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
+ with the version assumed by the caller (ZLIB_VERSION). msg is set to null
+ if there is no error message. deflateInit does not perform any compression:
+ this will be done by deflate().
+*/
+
+
+ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
+/*
+ deflate compresses as much data as possible, and stops when the input
+ buffer becomes empty or the output buffer becomes full. It may introduce
+ some output latency (reading input without producing any output) except when
+ forced to flush.
+
+ The detailed semantics are as follows. deflate performs one or both of the
+ following actions:
+
+ - Compress more input starting at next_in and update next_in and avail_in
+ accordingly. If not all input can be processed (because there is not
+ enough room in the output buffer), next_in and avail_in are updated and
+ processing will resume at this point for the next call of deflate().
+
+ - Provide more output starting at next_out and update next_out and avail_out
+ accordingly. This action is forced if the parameter flush is non zero.
+ Forcing flush frequently degrades the compression ratio, so this parameter
+ should be set only when necessary (in interactive applications). Some
+ output may be provided even if flush is not set.
+
+ Before the call of deflate(), the application should ensure that at least
+ one of the actions is possible, by providing more input and/or consuming more
+ output, and updating avail_in or avail_out accordingly; avail_out should
+ never be zero before the call. The application can consume the compressed
+ output when it wants, for example when the output buffer is full (avail_out
+ == 0), or after each call of deflate(). If deflate returns Z_OK and with
+ zero avail_out, it must be called again after making room in the output
+ buffer because there might be more output pending.
+
+ Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
+ decide how much data to accumulate before producing output, in order to
+ maximize compression.
+
+ If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
+ flushed to the output buffer and the output is aligned on a byte boundary, so
+ that the decompressor can get all input data available so far. (In
+ particular avail_in is zero after the call if enough output space has been
+ provided before the call.) Flushing may degrade compression for some
+ compression algorithms and so it should be used only when necessary. This
+ completes the current deflate block and follows it with an empty stored block
+ that is three bits plus filler bits to the next byte, followed by four bytes
+ (00 00 ff ff).
+
+ If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
+ output buffer, but the output is not aligned to a byte boundary. All of the
+ input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
+ This completes the current deflate block and follows it with an empty fixed
+ codes block that is 10 bits long. This assures that enough bytes are output
+ in order for the decompressor to finish the block before the empty fixed code
+ block.
+
+ If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
+ for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
+ seven bits of the current block are held to be written as the next byte after
+ the next deflate block is completed. In this case, the decompressor may not
+ be provided enough bits at this point in order to complete decompression of
+ the data provided so far to the compressor. It may need to wait for the next
+ block to be emitted. This is for advanced applications that need to control
+ the emission of deflate blocks.
+
+ If flush is set to Z_FULL_FLUSH, all output is flushed as with
+ Z_SYNC_FLUSH, and the compression state is reset so that decompression can
+ restart from this point if previous compressed data has been damaged or if
+ random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
+ compression.
+
+ If deflate returns with avail_out == 0, this function must be called again
+ with the same value of the flush parameter and more output space (updated
+ avail_out), until the flush is complete (deflate returns with non-zero
+ avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
+ avail_out is greater than six to avoid repeated flush markers due to
+ avail_out == 0 on return.
+
+ If the parameter flush is set to Z_FINISH, pending input is processed,
+ pending output is flushed and deflate returns with Z_STREAM_END if there was
+ enough output space; if deflate returns with Z_OK, this function must be
+ called again with Z_FINISH and more output space (updated avail_out) but no
+ more input data, until it returns with Z_STREAM_END or an error. After
+ deflate has returned Z_STREAM_END, the only possible operations on the stream
+ are deflateReset or deflateEnd.
+
+ Z_FINISH can be used immediately after deflateInit if all the compression
+ is to be done in a single step. In this case, avail_out must be at least the
+ value returned by deflateBound (see below). Then deflate is guaranteed to
+ return Z_STREAM_END. If not enough output space is provided, deflate will
+ not return Z_STREAM_END, and it must be called again as described above.
+
+ deflate() sets strm->adler to the adler32 checksum of all input read
+ so far (that is, total_in bytes).
+
+ deflate() may update strm->data_type if it can make a good guess about
+ the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
+ binary. This field is only for information purposes and does not affect the
+ compression algorithm in any manner.
+
+ deflate() returns Z_OK if some progress has been made (more input
+ processed or more output produced), Z_STREAM_END if all input has been
+ consumed and all output has been produced (only when flush is set to
+ Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
+ if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
+ (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
+ fatal, and deflate() can be called again with more input and more output
+ space to continue compressing.
+*/
+
+
+ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
+/*
+ All dynamically allocated data structures for this stream are freed.
+ This function discards any unprocessed input and does not flush any pending
+ output.
+
+ deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
+ stream state was inconsistent, Z_DATA_ERROR if the stream was freed
+ prematurely (some input or output was discarded). In the error case, msg
+ may be set but then points to a static string (which must not be
+ deallocated).
+*/
+
+
+/*
+ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
+
+ Initializes the internal stream state for decompression. The fields
+ next_in, avail_in, zalloc, zfree and opaque must be initialized before by
+ the caller. If next_in is not Z_NULL and avail_in is large enough (the
+ exact value depends on the compression method), inflateInit determines the
+ compression method from the zlib header and allocates all data structures
+ accordingly; otherwise the allocation will be deferred to the first call of
+ inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
+ use default allocation functions.
+
+ inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
+ memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
+ version assumed by the caller, or Z_STREAM_ERROR if the parameters are
+ invalid, such as a null pointer to the structure. msg is set to null if
+ there is no error message. inflateInit does not perform any decompression
+ apart from possibly reading the zlib header if present: actual decompression
+ will be done by inflate(). (So next_in and avail_in may be modified, but
+ next_out and avail_out are unused and unchanged.) The current implementation
+ of inflateInit() does not process any header information -- that is deferred
+ until inflate() is called.
+*/
+
+
+ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
+/*
+ inflate decompresses as much data as possible, and stops when the input
+ buffer becomes empty or the output buffer becomes full. It may introduce
+ some output latency (reading input without producing any output) except when
+ forced to flush.
+
+ The detailed semantics are as follows. inflate performs one or both of the
+ following actions:
+
+ - Decompress more input starting at next_in and update next_in and avail_in
+ accordingly. If not all input can be processed (because there is not
+ enough room in the output buffer), next_in is updated and processing will
+ resume at this point for the next call of inflate().
+
+ - Provide more output starting at next_out and update next_out and avail_out
+ accordingly. inflate() provides as much output as possible, until there is
+ no more input data or no more space in the output buffer (see below about
+ the flush parameter).
+
+ Before the call of inflate(), the application should ensure that at least
+ one of the actions is possible, by providing more input and/or consuming more
+ output, and updating the next_* and avail_* values accordingly. The
+ application can consume the uncompressed output when it wants, for example
+ when the output buffer is full (avail_out == 0), or after each call of
+ inflate(). If inflate returns Z_OK and with zero avail_out, it must be
+ called again after making room in the output buffer because there might be
+ more output pending.
+
+ The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
+ Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
+ output as possible to the output buffer. Z_BLOCK requests that inflate()
+ stop if and when it gets to the next deflate block boundary. When decoding
+ the zlib or gzip format, this will cause inflate() to return immediately
+ after the header and before the first block. When doing a raw inflate,
+ inflate() will go ahead and process the first block, and will return when it
+ gets to the end of that block, or when it runs out of data.
+
+ The Z_BLOCK option assists in appending to or combining deflate streams.
+ Also to assist in this, on return inflate() will set strm->data_type to the
+ number of unused bits in the last byte taken from strm->next_in, plus 64 if
+ inflate() is currently decoding the last block in the deflate stream, plus
+ 128 if inflate() returned immediately after decoding an end-of-block code or
+ decoding the complete header up to just before the first byte of the deflate
+ stream. The end-of-block will not be indicated until all of the uncompressed
+ data from that block has been written to strm->next_out. The number of
+ unused bits may in general be greater than seven, except when bit 7 of
+ data_type is set, in which case the number of unused bits will be less than
+ eight. data_type is set as noted here every time inflate() returns for all
+ flush options, and so can be used to determine the amount of currently
+ consumed input in bits.
+
+ The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
+ end of each deflate block header is reached, before any actual data in that
+ block is decoded. This allows the caller to determine the length of the
+ deflate block header for later use in random access within a deflate block.
+ 256 is added to the value of strm->data_type when inflate() returns
+ immediately after reaching the end of the deflate block header.
+
+ 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 of the uncompressed data for the
+ operation to complete. (The size of the uncompressed data may have been
+ saved by the compressor for this purpose.) The use of Z_FINISH is not
+ required to perform an inflation in one step. However it may be used to
+ inform inflate that a faster approach can be used for the single inflate()
+ call. Z_FINISH also informs inflate to not maintain a sliding window if the
+ stream completes, which reduces inflate's memory footprint. If the stream
+ does not complete, either because not all of the stream is provided or not
+ enough output space is provided, then a sliding window will be allocated and
+ inflate() can be called again to continue the operation as if Z_NO_FLUSH had
+ been used.
+
+ In this implementation, inflate() always flushes as much output as
+ possible to the output buffer, and always uses the faster approach on the
+ first call. So the effects of the flush parameter in this implementation are
+ on the return value of inflate() as noted below, when inflate() returns early
+ when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
+ memory for a sliding window when Z_FINISH is used.
+
+ If a preset dictionary is needed after this call (see inflateSetDictionary
+ below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
+ chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
+ strm->adler to the Adler-32 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() can decompress and check either zlib-wrapped or gzip-wrapped
+ deflate data. The header type is detected automatically, if requested when
+ initializing with inflateInit2(). Any information contained in the gzip
+ header is not retained, so applications that need that information should
+ instead use raw inflate, see inflateInit2() below, or inflateBack() and
+ perform their own processing of the gzip header and trailer. When processing
+ gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
+ producted so far. The CRC-32 is checked against the gzip trailer.
+
+ inflate() returns Z_OK if some progress has been made (more input processed
+ or more output produced), Z_STREAM_END if the end of the compressed data has
+ been reached and all uncompressed output has been produced, Z_NEED_DICT if a
+ preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
+ corrupted (input stream not conforming to the zlib format or incorrect check
+ value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
+ next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
+ Z_BUF_ERROR if no progress is possible or if there was not enough room in the
+ output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
+ inflate() can be called again with more input and more output space to
+ continue decompressing. If Z_DATA_ERROR is returned, the application may
+ then call inflateSync() to look for a good compression block if a partial
+ recovery of the data is desired.
+*/
+
+
+ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
+/*
+ All dynamically allocated data structures for this stream are freed.
+ This function discards any unprocessed input and does not flush any pending
+ output.
+
+ inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
+ was inconsistent. In the error case, msg may be set but then points to a
+ static string (which must not be deallocated).
+*/
+
+
+ /* Advanced functions */
+
+/*
+ The following functions are needed only in some special applications.
+*/
+
+/*
+ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
+ int level,
+ int method,
+ int windowBits,
+ int memLevel,
+ int strategy));
+
+ This is another version of deflateInit with more compression options. The
+ fields next_in, zalloc, zfree and opaque must be initialized before by the
+ caller.
+
+ The method parameter is the compression method. It must be Z_DEFLATED in
+ this version of the library.
+
+ The windowBits parameter is the base two logarithm of the window size
+ (the size of the history buffer). It should be in the range 8..15 for this
+ version of the library. Larger values of this parameter result in better
+ compression at the expense of memory usage. The default value is 15 if
+ deflateInit is used instead.
+
+ windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
+ determines the window size. deflate() will then generate raw deflate data
+ with no zlib header or trailer, and will not compute an adler32 check value.
+
+ windowBits can also be greater than 15 for optional gzip encoding. Add
+ 16 to windowBits to write a simple gzip header and trailer around the
+ compressed data instead of a zlib wrapper. The gzip header will have no
+ file name, no extra data, no comment, no modification time (set to zero), no
+ header crc, and the operating system will be set to 255 (unknown). If a
+ gzip stream is being written, strm->adler is a crc32 instead of an adler32.
+
+ The memLevel parameter specifies how much memory should be allocated
+ for the internal compression state. memLevel=1 uses minimum memory but is
+ slow and reduces compression ratio; memLevel=9 uses maximum memory for
+ optimal speed. The default value is 8. See zconf.h for total memory usage
+ as a function of windowBits and memLevel.
+
+ The strategy parameter is used to tune the compression algorithm. Use the
+ value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
+ filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
+ string match), or Z_RLE to limit match distances to one (run-length
+ encoding). Filtered data consists mostly of small values with a somewhat
+ random distribution. In this case, the compression algorithm is tuned to
+ compress them better. The effect of Z_FILTERED is to force more Huffman
+ coding and less string matching; it is somewhat intermediate between
+ Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
+ fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
+ strategy parameter only affects the compression ratio but not the
+ correctness of the compressed output even if it is not set appropriately.
+ Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
+ decoder for special applications.
+
+ deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
+ memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
+ method), or 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. deflateInit2 does not perform any
+ compression: this will be done by deflate().
+*/
+
+ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
+ const Bytef *dictionary,
+ uInt dictLength));
+/*
+ Initializes the compression dictionary from the given byte sequence
+ without producing any compressed output. When using the zlib format, this
+ function must be called immediately after deflateInit, deflateInit2 or
+ deflateReset, and before any call of deflate. When doing raw deflate, this
+ function must be called either before any call of deflate, or immediately
+ after the completion of a deflate block, i.e. after all input has been
+ consumed and all output has been delivered when using any of the flush
+ options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. 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
+ provided in deflateInit or deflateInit2. Thus the strings most likely to be
+ useful should be put at the end of the dictionary, not at the front. In
+ addition, the current implementation of deflate will use at most the window
+ size minus 262 bytes of the provided dictionary.
+
+ Upon return of this function, strm->adler is set to the adler32 value
+ of the dictionary; the decompressor may later use this value to determine
+ which dictionary has been used by the compressor. (The adler32 value
+ applies to the whole dictionary even if only a subset of the dictionary is
+ actually used by the compressor.) If a raw deflate was requested, then the
+ adler32 value is not computed and strm->adler is not set.
+
+ deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
+ parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
+ inconsistent (for example if deflate has already been called for this stream
+ or if not at a block boundary for raw deflate). deflateSetDictionary does
+ not perform any compression: this will be done by deflate().
+*/
+
+ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
+ z_streamp source));
+/*
+ Sets the destination stream as a complete copy of the source stream.
+
+ This function can be useful when several compression strategies will be
+ tried, for example when there are several ways of pre-processing the input
+ data with a filter. The streams that will be discarded should then be freed
+ by calling deflateEnd. Note that deflateCopy duplicates the internal
+ compression state which can be quite large, so this strategy is slow and can
+ consume lots of memory.
+
+ deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
+ enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
+ (such as zalloc being Z_NULL). msg is left unchanged in both source and
+ destination.
+*/
+
+ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
+/*
+ This function is equivalent to deflateEnd followed by deflateInit,
+ but does not free and reallocate all the internal compression state. The
+ stream will keep the same compression level and any other attributes that
+ may have been set by deflateInit2.
+
+ deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
+ stream state was inconsistent (such as zalloc or state being Z_NULL).
+*/
+
+ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
+ int level,
+ int strategy));
+/*
+ Dynamically update the compression level and compression strategy. The
+ interpretation of level and strategy is as in deflateInit2. This can be
+ used to switch between compression and straight copy of the input data, or
+ to switch to a different kind of input data requiring a different strategy.
+ If the compression level is changed, the input available so far is
+ compressed with the old level (and may be flushed); the new level will take
+ effect only at the next call of deflate().
+
+ Before the call of deflateParams, the stream state must be set as for
+ a call of deflate(), since the currently available input may have to be
+ compressed and flushed. In particular, strm->avail_out must be non-zero.
+
+ deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
+ stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
+ strm->avail_out was zero.
+*/
+
+ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
+ int good_length,
+ int max_lazy,
+ int nice_length,
+ int max_chain));
+/*
+ Fine tune deflate's internal compression parameters. This should only be
+ used by someone who understands the algorithm used by zlib's deflate for
+ searching for the best matching string, and even then only by the most
+ fanatic optimizer trying to squeeze out the last compressed bit for their
+ specific input data. Read the deflate.c source code for the meaning of the
+ max_lazy, good_length, nice_length, and max_chain parameters.
+
+ deflateTune() can be called after deflateInit() or deflateInit2(), and
+ returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
+ */
+
+ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
+ uLong sourceLen));
+/*
+ deflateBound() returns an upper bound on the compressed size after
+ deflation of sourceLen bytes. It must be called after deflateInit() or
+ deflateInit2(), and after deflateSetHeader(), if used. This would be used
+ to allocate an output buffer for deflation in a single pass, and so would be
+ called before deflate(). If that first deflate() call is provided the
+ sourceLen input bytes, an output buffer allocated to the size returned by
+ deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
+ to return Z_STREAM_END. Note that it is possible for the compressed size to
+ be larger than the value returned by deflateBound() if flush options other
+ than Z_FINISH or Z_NO_FLUSH are used.
+*/
+
+ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
+ unsigned *pending,
+ int *bits));
+/*
+ deflatePending() returns the number of bytes and bits of output that have
+ been generated, but not yet provided in the available output. The bytes not
+ provided would be due to the available output space having being consumed.
+ The number of bits of output not provided are between 0 and 7, where they
+ await more bits to join them in order to fill out a full byte. If pending
+ or bits are Z_NULL, then those values are not set.
+
+ deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
+ stream state was inconsistent.
+ */
+
+ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
+ int bits,
+ int value));
+/*
+ deflatePrime() inserts bits in the deflate output stream. The intent
+ is that this function is used to start off the deflate output with the bits
+ leftover from a previous deflate stream when appending to it. As such, this
+ function can only be used for raw deflate, and must be used before the first
+ deflate() call after a deflateInit2() or deflateReset(). bits must be less
+ than or equal to 16, and that many of the least significant bits of value
+ will be inserted in the output.
+
+ deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
+ room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
+ source stream state was inconsistent.
+*/
+
+ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
+ gz_headerp head));
+/*
+ deflateSetHeader() provides gzip header information for when a gzip
+ stream is requested by deflateInit2(). deflateSetHeader() may be called
+ after deflateInit2() or deflateReset() and before the first call of
+ deflate(). The text, time, os, extra field, name, and comment information
+ in the provided gz_header structure are written to the gzip header (xflag is
+ ignored -- the extra flags are set according to the compression level). The
+ caller must assure that, if not Z_NULL, name and comment are terminated with
+ a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
+ available there. If hcrc is true, a gzip header crc is included. Note that
+ the current versions of the command-line version of gzip (up through version
+ 1.3.x) do not support header crc's, and will report that it is a "multi-part
+ gzip file" and give up.
+
+ If deflateSetHeader is not used, the default gzip header has text false,
+ the time set to zero, and os set to 255, with no extra, name, or comment
+ fields. The gzip header is returned to the default state by deflateReset().
+
+ deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
+ stream state was inconsistent.
+*/
+
+/*
+ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
+ int windowBits));
+
+ This is another version of inflateInit with an extra parameter. The
+ fields next_in, avail_in, zalloc, zfree and opaque must be initialized
+ before by the caller.
+
+ The windowBits parameter is the base two logarithm of the maximum window
+ size (the size of the history buffer). It should be in the range 8..15 for
+ this version of the library. The default value is 15 if inflateInit is used
+ instead. windowBits must be greater than or equal to the windowBits value
+ provided to deflateInit2() while compressing, or it must be equal to 15 if
+ deflateInit2() was not used. If a compressed stream with a larger window
+ size is given as input, inflate() will return with the error code
+ Z_DATA_ERROR instead of trying to allocate a larger window.
+
+ windowBits can also be zero to request that inflate use the window size in
+ the zlib header of the compressed stream.
+
+ windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
+ determines the window size. inflate() will then process raw deflate data,
+ not looking for a zlib or gzip header, not generating a check value, and not
+ looking for any check values for comparison at the end of the stream. This
+ is for use with other formats that use the deflate compressed data format
+ such as zip. Those formats provide their own check values. If a custom
+ format is developed using the raw deflate format for compressed data, it is
+ recommended that a check value such as an adler32 or a crc32 be applied to
+ the uncompressed data as is done in the zlib, gzip, and zip formats. For
+ most applications, the zlib format should be used as is. Note that comments
+ above on the use in deflateInit2() applies to the magnitude of windowBits.
+
+ windowBits can also be greater than 15 for optional gzip decoding. Add
+ 32 to windowBits to enable zlib and gzip decoding with automatic header
+ detection, or add 16 to decode only the gzip format