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893 lines
41 KiB
893 lines
41 KiB
/* zlib.h -- interface of the 'zlib' general purpose compression library |
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version 1.1.4, March 11th, 2002 |
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Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler |
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This software is provided 'as-is', without any express or implied |
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warranty. In no event will the authors be held liable for any damages |
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arising from the use of this software. |
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Permission is granted to anyone to use this software for any purpose, |
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including commercial applications, and to alter it and redistribute it |
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freely, subject to the following restrictions: |
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1. The origin of this software must not be misrepresented; you must not |
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claim that you wrote the original software. If you use this software |
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in a product, an acknowledgment in the product documentation would be |
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appreciated but is not required. |
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2. Altered source versions must be plainly marked as such, and must not be |
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misrepresented as being the original software. |
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3. This notice may not be removed or altered from any source distribution. |
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Jean-loup Gailly Mark Adler |
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jloup@gzip.org madler@alumni.caltech.edu |
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The data format used by the zlib library is described by RFCs (Request for |
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Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt |
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(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). |
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*/ |
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#ifndef _ZLIB_H |
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#define _ZLIB_H |
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#include "zconf.h" |
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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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#define ZLIB_VERSION "1.1.4" |
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/* |
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The 'zlib' compression library provides in-memory compression and |
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decompression functions, including integrity checks of the uncompressed |
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data. This version of the library supports only one compression method |
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(deflation) but other algorithms will be added later and will have the same |
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stream interface. |
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Compression can be done in a single step if the buffers are large |
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enough (for example if an input file is mmap'ed), or can be done by |
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repeated calls of the compression function. In the latter case, the |
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application must provide more input and/or consume the output |
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(providing more output space) before each call. |
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The library also supports reading and writing files in gzip (.gz) format |
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with an interface similar to that of stdio. |
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The library does not install any signal handler. The decoder checks |
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the consistency of the compressed data, so the library should never |
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crash even in case of corrupted input. |
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*/ |
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typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
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typedef void (*free_func) OF((voidpf opaque, voidpf address)); |
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struct internal_state; |
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typedef struct z_stream_s { |
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Bytef *next_in; /* next input byte */ |
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uInt avail_in; /* number of bytes available at next_in */ |
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uLong total_in; /* total nb of input bytes read so far */ |
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Bytef *next_out; /* next output byte should be put there */ |
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uInt avail_out; /* remaining free space at next_out */ |
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uLong total_out; /* total nb of bytes output so far */ |
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char *msg; /* last error message, NULL if no error */ |
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struct internal_state FAR *state; /* not visible by applications */ |
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alloc_func zalloc; /* used to allocate the internal state */ |
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free_func zfree; /* used to free the internal state */ |
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voidpf opaque; /* private data object passed to zalloc and zfree */ |
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int data_type; /* best guess about the data type: ascii or binary */ |
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uLong adler; /* adler32 value of the uncompressed data */ |
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uLong reserved; /* reserved for future use */ |
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} z_stream; |
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typedef z_stream FAR *z_streamp; |
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/* |
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The application must update next_in and avail_in when avail_in has |
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dropped to zero. It must update next_out and avail_out when avail_out |
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has dropped to zero. The application must initialize zalloc, zfree and |
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opaque before calling the init function. All other fields are set by the |
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compression library and must not be updated by the application. |
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The opaque value provided by the application will be passed as the first |
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parameter for calls of zalloc and zfree. This can be useful for custom |
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memory management. The compression library attaches no meaning to the |
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opaque value. |
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zalloc must return Z_NULL if there is not enough memory for the object. |
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If zlib is used in a multi-threaded application, zalloc and zfree must be |
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thread safe. |
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On 16-bit systems, the functions zalloc and zfree must be able to allocate |
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exactly 65536 bytes, but will not be required to allocate more than this |
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if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, |
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pointers returned by zalloc for objects of exactly 65536 bytes *must* |
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have their offset normalized to zero. The default allocation function |
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provided by this library ensures this (see zutil.c). To reduce memory |
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requirements and avoid any allocation of 64K objects, at the expense of |
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compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). |
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The fields total_in and total_out can be used for statistics or |
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progress reports. After compression, total_in holds the total size of |
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the uncompressed data and may be saved for use in the decompressor |
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(particularly if the decompressor wants to decompress everything in |
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a single step). |
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*/ |
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/* constants */ |
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#define Z_NO_FLUSH 0 |
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#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ |
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#define Z_SYNC_FLUSH 2 |
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#define Z_FULL_FLUSH 3 |
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#define Z_FINISH 4 |
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/* Allowed flush values; see deflate() below for details */ |
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#define Z_OK 0 |
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#define Z_STREAM_END 1 |
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#define Z_NEED_DICT 2 |
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#define Z_ERRNO (-1) |
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#define Z_STREAM_ERROR (-2) |
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#define Z_DATA_ERROR (-3) |
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#define Z_MEM_ERROR (-4) |
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#define Z_BUF_ERROR (-5) |
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#define Z_VERSION_ERROR (-6) |
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/* Return codes for the compression/decompression functions. Negative |
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* values are errors, positive values are used for special but normal events. |
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*/ |
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#define Z_NO_COMPRESSION 0 |
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#define Z_BEST_SPEED 1 |
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#define Z_BEST_COMPRESSION 9 |
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#define Z_DEFAULT_COMPRESSION (-1) |
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/* compression levels */ |
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#define Z_FILTERED 1 |
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#define Z_HUFFMAN_ONLY 2 |
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#define Z_DEFAULT_STRATEGY 0 |
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/* compression strategy; see deflateInit2() below for details */ |
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#define Z_BINARY 0 |
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#define Z_ASCII 1 |
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#define Z_UNKNOWN 2 |
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/* Possible values of the data_type field */ |
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#define Z_DEFLATED 8 |
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/* The deflate compression method (the only one supported in this version) */ |
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#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ |
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#define zlib_version zlibVersion() |
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/* for compatibility with versions < 1.0.2 */ |
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/* basic functions */ |
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ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
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/* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
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If the first character differs, the library code actually used is |
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not compatible with the zlib.h header file used by the application. |
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This check is automatically made by deflateInit and inflateInit. |
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*/ |
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/* |
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ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); |
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Initializes the internal stream state for compression. The fields |
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zalloc, zfree and opaque must be initialized before by the caller. |
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If zalloc and zfree are set to Z_NULL, deflateInit updates them to |
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use default allocation functions. |
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The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
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1 gives best speed, 9 gives best compression, 0 gives no compression at |
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all (the input data is simply copied a block at a time). |
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Z_DEFAULT_COMPRESSION requests a default compromise between speed and |
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compression (currently equivalent to level 6). |
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deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
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enough memory, Z_STREAM_ERROR if level is not a valid compression level, |
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Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
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with the version assumed by the caller (ZLIB_VERSION). |
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msg is set to null if there is no error message. deflateInit does not |
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perform any compression: this will be done by deflate(). |
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*/ |
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ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
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/* |
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deflate compresses as much data as possible, and stops when the input |
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buffer becomes empty or the output buffer becomes full. It may introduce some |
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output latency (reading input without producing any output) except when |
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forced to flush. |
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The detailed semantics are as follows. deflate performs one or both of the |
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following actions: |
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- Compress more input starting at next_in and update next_in and avail_in |
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accordingly. If not all input can be processed (because there is not |
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enough room in the output buffer), next_in and avail_in are updated and |
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processing will resume at this point for the next call of deflate(). |
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- Provide more output starting at next_out and update next_out and avail_out |
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accordingly. This action is forced if the parameter flush is non zero. |
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Forcing flush frequently degrades the compression ratio, so this parameter |
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should be set only when necessary (in interactive applications). |
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Some output may be provided even if flush is not set. |
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Before the call of deflate(), the application should ensure that at least |
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one of the actions is possible, by providing more input and/or consuming |
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more output, and updating avail_in or avail_out accordingly; avail_out |
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should never be zero before the call. The application can consume the |
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compressed output when it wants, for example when the output buffer is full |
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(avail_out == 0), or after each call of deflate(). If deflate returns Z_OK |
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and with zero avail_out, it must be called again after making room in the |
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output buffer because there might be more output pending. |
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If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
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flushed to the output buffer and the output is aligned on a byte boundary, so |
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that the decompressor can get all input data available so far. (In particular |
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avail_in is zero after the call if enough output space has been provided |
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before the call.) Flushing may degrade compression for some compression |
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algorithms and so it should be used only when necessary. |
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If flush is set to Z_FULL_FLUSH, all output is flushed as with |
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Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
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restart from this point if previous compressed data has been damaged or if |
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random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
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the compression. |
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If deflate returns with avail_out == 0, this function must be called again |
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with the same value of the flush parameter and more output space (updated |
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avail_out), until the flush is complete (deflate returns with non-zero |
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avail_out). |
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If the parameter flush is set to Z_FINISH, pending input is processed, |
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pending output is flushed and deflate returns with Z_STREAM_END if there |
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was enough output space; if deflate returns with Z_OK, this function must be |
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called again with Z_FINISH and more output space (updated avail_out) but no |
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more input data, until it returns with Z_STREAM_END or an error. After |
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deflate has returned Z_STREAM_END, the only possible operations on the |
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stream are deflateReset or deflateEnd. |
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Z_FINISH can be used immediately after deflateInit if all the compression |
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is to be done in a single step. In this case, avail_out must be at least |
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0.1% larger than avail_in plus 12 bytes. If deflate does not return |
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Z_STREAM_END, then it must be called again as described above. |
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deflate() sets strm->adler to the adler32 checksum of all input read |
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so far (that is, total_in bytes). |
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deflate() may update data_type if it can make a good guess about |
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the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered |
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binary. This field is only for information purposes and does not affect |
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the compression algorithm in any manner. |
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deflate() returns Z_OK if some progress has been made (more input |
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processed or more output produced), Z_STREAM_END if all input has been |
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consumed and all output has been produced (only when flush is set to |
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Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
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if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
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(for example avail_in or avail_out was zero). |
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*/ |
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ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); |
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/* |
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All dynamically allocated data structures for this stream are freed. |
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This function discards any unprocessed input and does not flush any |
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pending output. |
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deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
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stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
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prematurely (some input or output was discarded). In the error case, |
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msg may be set but then points to a static string (which must not be |
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deallocated). |
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*/ |
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/* |
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ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
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Initializes the internal stream state for decompression. The fields |
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next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
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the caller. If next_in is not Z_NULL and avail_in is large enough (the exact |
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value depends on the compression method), inflateInit determines the |
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compression method from the zlib header and allocates all data structures |
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accordingly; otherwise the allocation will be deferred to the first call of |
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inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to |
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use default allocation functions. |
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inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
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version assumed by the caller. msg is set to null if there is no error |
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message. inflateInit does not perform any decompression apart from reading |
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the zlib header if present: this will be done by inflate(). (So next_in and |
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avail_in may be modified, but next_out and avail_out are unchanged.) |
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*/ |
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ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); |
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/* |
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inflate decompresses as much data as possible, and stops when the input |
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buffer becomes empty or the output buffer becomes full. It may some |
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introduce some output latency (reading input without producing any output) |
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except when forced to flush. |
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The detailed semantics are as follows. inflate performs one or both of the |
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following actions: |
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- Decompress more input starting at next_in and update next_in and avail_in |
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accordingly. If not all input can be processed (because there is not |
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enough room in the output buffer), next_in is updated and processing |
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will resume at this point for the next call of inflate(). |
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- Provide more output starting at next_out and update next_out and avail_out |
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accordingly. inflate() provides as much output as possible, until there |
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is no more input data or no more space in the output buffer (see below |
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about the flush parameter). |
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Before the call of inflate(), the application should ensure that at least |
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one of the actions is possible, by providing more input and/or consuming |
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more output, and updating the next_* and avail_* values accordingly. |
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The application can consume the uncompressed output when it wants, for |
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example when the output buffer is full (avail_out == 0), or after each |
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call of inflate(). If inflate returns Z_OK and with zero avail_out, it |
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must be called again after making room in the output buffer because there |
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might be more output pending. |
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If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much |
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output as possible to the output buffer. The flushing behavior of inflate is |
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not specified for values of the flush parameter other than Z_SYNC_FLUSH |
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and Z_FINISH, but the current implementation actually flushes as much output |
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as possible anyway. |
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inflate() should normally be called until it returns Z_STREAM_END or an |
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error. However if all decompression is to be performed in a single step |
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(a single call of inflate), the parameter flush should be set to |
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Z_FINISH. In this case all pending input is processed and all pending |
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output is flushed; avail_out must be large enough to hold all the |
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uncompressed data. (The size of the uncompressed data may have been saved |
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by the compressor for this purpose.) The next operation on this stream must |
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be inflateEnd to deallocate the decompression state. The use of Z_FINISH |
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is never required, but can be used to inform inflate that a faster routine |
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may be used for the single inflate() call. |
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If a preset dictionary is needed at this point (see inflateSetDictionary |
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below), inflate sets strm-adler to the adler32 checksum of the |
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dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise |
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it sets strm->adler to the adler32 checksum of all output produced |
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so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or |
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an error code as described below. At the end of the stream, inflate() |
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checks that its computed adler32 checksum is equal to that saved by the |
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compressor and returns Z_STREAM_END only if the checksum is correct. |
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inflate() returns Z_OK if some progress has been made (more input processed |
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or more output produced), Z_STREAM_END if the end of the compressed data has |
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been reached and all uncompressed output has been produced, Z_NEED_DICT if a |
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preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
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corrupted (input stream not conforming to the zlib format or incorrect |
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adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent |
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(for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not |
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enough memory, Z_BUF_ERROR if no progress is possible or if there was not |
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enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR |
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case, the application may then call inflateSync to look for a good |
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compression block. |
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*/ |
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ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); |
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/* |
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All dynamically allocated data structures for this stream are freed. |
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This function discards any unprocessed input and does not flush any |
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pending output. |
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inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
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was inconsistent. In the error case, msg may be set but then points to a |
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static string (which must not be deallocated). |
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*/ |
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/* Advanced functions */ |
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/* |
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The following functions are needed only in some special applications. |
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*/ |
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/* |
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ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, |
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int level, |
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int method, |
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int windowBits, |
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int memLevel, |
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int strategy)); |
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|
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This is another version of deflateInit with more compression options. The |
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fields next_in, zalloc, zfree and opaque must be initialized before by |
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the caller. |
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The method parameter is the compression method. It must be Z_DEFLATED in |
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this version of the library. |
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|
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The windowBits parameter is the base two logarithm of the window size |
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(the size of the history buffer). It should be in the range 8..15 for this |
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version of the library. Larger values of this parameter result in better |
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compression at the expense of memory usage. The default value is 15 if |
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deflateInit is used instead. |
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|
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The memLevel parameter specifies how much memory should be allocated |
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for the internal compression state. memLevel=1 uses minimum memory but |
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is slow and reduces compression ratio; memLevel=9 uses maximum memory |
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for optimal speed. The default value is 8. See zconf.h for total memory |
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usage as a function of windowBits and memLevel. |
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|
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The strategy parameter is used to tune the compression algorithm. Use the |
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value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
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filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no |
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string match). Filtered data consists mostly of small values with a |
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somewhat random distribution. In this case, the compression algorithm is |
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tuned to compress them better. The effect of Z_FILTERED is to force more |
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Huffman coding and less string matching; it is somewhat intermediate |
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between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects |
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the compression ratio but not the correctness of the compressed output even |
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if it is not set appropriately. |
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deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
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memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
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method). msg is set to null if there is no error message. deflateInit2 does |
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not perform any compression: this will be done by deflate(). |
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*/ |
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ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
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const Bytef *dictionary, |
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uInt dictLength)); |
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/* |
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Initializes the compression dictionary from the given byte sequence |
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without producing any compressed output. This function must be called |
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immediately after deflateInit, deflateInit2 or deflateReset, before any |
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call of deflate. The compressor and decompressor must use exactly the same |
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dictionary (see inflateSetDictionary). |
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The dictionary should consist of strings (byte sequences) that are likely |
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to be encountered later in the data to be compressed, with the most commonly |
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used strings preferably put towards the end of the dictionary. Using a |
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dictionary is most useful when the data to be compressed is short and can be |
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predicted with good accuracy; the data can then be compressed better than |
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with the default empty dictionary. |
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|
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Depending on the size of the compression data structures selected by |
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deflateInit or deflateInit2, a part of the dictionary may in effect be |
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discarded, for example if the dictionary is larger than the window size in |
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deflate or deflate2. Thus the strings most likely to be useful should be |
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put at the end of the dictionary, not at the front. |
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|
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Upon return of this function, strm->adler is set to the Adler32 value |
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of the dictionary; the decompressor may later use this value to determine |
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which dictionary has been used by the compressor. (The Adler32 value |
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applies to the whole dictionary even if only a subset of the dictionary is |
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actually used by the compressor.) |
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|
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deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
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parameter is invalid (such as NULL dictionary) or the stream state is |
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inconsistent (for example if deflate has already been called for this stream |
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or if the compression method is bsort). deflateSetDictionary does not |
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perform any compression: this will be done by deflate(). |
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*/ |
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|
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ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, |
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z_streamp source)); |
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/* |
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Sets the destination stream as a complete copy of the source stream. |
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|
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This function can be useful when several compression strategies will be |
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tried, for example when there are several ways of pre-processing the input |
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data with a filter. The streams that will be discarded should then be freed |
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by calling deflateEnd. Note that deflateCopy duplicates the internal |
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compression state which can be quite large, so this strategy is slow and |
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can consume lots of memory. |
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|
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deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
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enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
|
(such as zalloc being NULL). msg is left unchanged in both source and |
|
destination. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); |
|
/* |
|
This function is equivalent to deflateEnd followed by deflateInit, |
|
but does not free and reallocate all the internal compression state. |
|
The stream will keep the same compression level and any other attributes |
|
that may have been set by deflateInit2. |
|
|
|
deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
|
stream state was inconsistent (such as zalloc or state being NULL). |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, |
|
int level, |
|
int strategy)); |
|
/* |
|
Dynamically update the compression level and compression strategy. The |
|
interpretation of level and strategy is as in deflateInit2. This can be |
|
used to switch between compression and straight copy of the input data, or |
|
to switch to a different kind of input data requiring a different |
|
strategy. If the compression level is changed, the input available so far |
|
is compressed with the old level (and may be flushed); the new level will |
|
take effect only at the next call of deflate(). |
|
|
|
Before the call of deflateParams, the stream state must be set as for |
|
a call of deflate(), since the currently available input may have to |
|
be compressed and flushed. In particular, strm->avail_out must be non-zero. |
|
|
|
deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
|
stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR |
|
if strm->avail_out was zero. |
|
*/ |
|
|
|
/* |
|
ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
|
int windowBits)); |
|
|
|
This is another version of inflateInit with an extra parameter. The |
|
fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
|
before by the caller. |
|
|
|
The windowBits parameter is the base two logarithm of the maximum window |
|
size (the size of the history buffer). It should be in the range 8..15 for |
|
this version of the library. The default value is 15 if inflateInit is used |
|
instead. If a compressed stream with a larger window size is given as |
|
input, inflate() will return with the error code Z_DATA_ERROR instead of |
|
trying to allocate a larger window. |
|
|
|
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
|
memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative |
|
memLevel). msg is set to null if there is no error message. inflateInit2 |
|
does not perform any decompression apart from reading the zlib header if |
|
present: this will be done by inflate(). (So next_in and avail_in may be |
|
modified, but next_out and avail_out are unchanged.) |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, |
|
const Bytef *dictionary, |
|
uInt dictLength)); |
|
/* |
|
Initializes the decompression dictionary from the given uncompressed byte |
|
sequence. This function must be called immediately after a call of inflate |
|
if this call returned Z_NEED_DICT. The dictionary chosen by the compressor |
|
can be determined from the Adler32 value returned by this call of |
|
inflate. The compressor and decompressor must use exactly the same |
|
dictionary (see deflateSetDictionary). |
|
|
|
inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
|
parameter is invalid (such as NULL dictionary) or the stream state is |
|
inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
|
expected one (incorrect Adler32 value). inflateSetDictionary does not |
|
perform any decompression: this will be done by subsequent calls of |
|
inflate(). |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); |
|
/* |
|
Skips invalid compressed data until a full flush point (see above the |
|
description of deflate with Z_FULL_FLUSH) can be found, or until all |
|
available input is skipped. No output is provided. |
|
|
|
inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
|
if no more input was provided, Z_DATA_ERROR if no flush point has been found, |
|
or Z_STREAM_ERROR if the stream structure was inconsistent. In the success |
|
case, the application may save the current current value of total_in which |
|
indicates where valid compressed data was found. In the error case, the |
|
application may repeatedly call inflateSync, providing more input each time, |
|
until success or end of the input data. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); |
|
/* |
|
This function is equivalent to inflateEnd followed by inflateInit, |
|
but does not free and reallocate all the internal decompression state. |
|
The stream will keep attributes that may have been set by inflateInit2. |
|
|
|
inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
|
stream state was inconsistent (such as zalloc or state being NULL). |
|
*/ |
|
|
|
|
|
/* utility functions */ |
|
|
|
/* |
|
The following utility functions are implemented on top of the |
|
basic stream-oriented functions. To simplify the interface, some |
|
default options are assumed (compression level and memory usage, |
|
standard memory allocation functions). The source code of these |
|
utility functions can easily be modified if you need special options. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, |
|
const Bytef *source, uLong sourceLen)); |
|
/* |
|
Compresses the source buffer into the destination buffer. sourceLen is |
|
the byte length of the source buffer. Upon entry, destLen is the total |
|
size of the destination buffer, which must be at least 0.1% larger than |
|
sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the |
|
compressed buffer. |
|
This function can be used to compress a whole file at once if the |
|
input file is mmap'ed. |
|
compress returns Z_OK if success, Z_MEM_ERROR if there was not |
|
enough memory, Z_BUF_ERROR if there was not enough room in the output |
|
buffer. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, |
|
const Bytef *source, uLong sourceLen, |
|
int level)); |
|
/* |
|
Compresses the source buffer into the destination buffer. The level |
|
parameter has the same meaning as in deflateInit. sourceLen is the byte |
|
length of the source buffer. Upon entry, destLen is the total size of the |
|
destination buffer, which must be at least 0.1% larger than sourceLen plus |
|
12 bytes. Upon exit, destLen is the actual size of the compressed buffer. |
|
|
|
compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
|
memory, Z_BUF_ERROR if there was not enough room in the output buffer, |
|
Z_STREAM_ERROR if the level parameter is invalid. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, |
|
const Bytef *source, uLong sourceLen)); |
|
/* |
|
Decompresses the source buffer into the destination buffer. sourceLen is |
|
the byte length of the source buffer. Upon entry, destLen is the total |
|
size of the destination buffer, which must be large enough to hold the |
|
entire uncompressed data. (The size of the uncompressed data must have |
|
been saved previously by the compressor and transmitted to the decompressor |
|
by some mechanism outside the scope of this compression library.) |
|
Upon exit, destLen is the actual size of the compressed buffer. |
|
This function can be used to decompress a whole file at once if the |
|
input file is mmap'ed. |
|
|
|
uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
|
enough memory, Z_BUF_ERROR if there was not enough room in the output |
|
buffer, or Z_DATA_ERROR if the input data was corrupted. |
|
*/ |
|
|
|
|
|
typedef voidp gzFile; |
|
|
|
ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
|
/* |
|
Opens a gzip (.gz) file for reading or writing. The mode parameter |
|
is as in fopen ("rb" or "wb") but can also include a compression level |
|
("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for |
|
Huffman only compression as in "wb1h". (See the description |
|
of deflateInit2 for more information about the strategy parameter.) |
|
|
|
gzopen can be used to read a file which is not in gzip format; in this |
|
case gzread will directly read from the file without decompression. |
|
|
|
gzopen returns NULL if the file could not be opened or if there was |
|
insufficient memory to allocate the (de)compression state; errno |
|
can be checked to distinguish the two cases (if errno is zero, the |
|
zlib error is Z_MEM_ERROR). */ |
|
|
|
ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
|
/* |
|
gzdopen() associates a gzFile with the file descriptor fd. File |
|
descriptors are obtained from calls like open, dup, creat, pipe or |
|
fileno (in the file has been previously opened with fopen). |
|
The mode parameter is as in gzopen. |
|
The next call of gzclose on the returned gzFile will also close the |
|
file descriptor fd, just like fclose(fdopen(fd), mode) closes the file |
|
descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). |
|
gzdopen returns NULL if there was insufficient memory to allocate |
|
the (de)compression state. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); |
|
/* |
|
Dynamically update the compression level or strategy. See the description |
|
of deflateInit2 for the meaning of these parameters. |
|
gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
|
opened for writing. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
|
/* |
|
Reads the given number of uncompressed bytes from the compressed file. |
|
If the input file was not in gzip format, gzread copies the given number |
|
of bytes into the buffer. |
|
gzread returns the number of uncompressed bytes actually read (0 for |
|
end of file, -1 for error). */ |
|
|
|
ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
|
const voidp buf, unsigned len)); |
|
/* |
|
Writes the given number of uncompressed bytes into the compressed file. |
|
gzwrite returns the number of uncompressed bytes actually written |
|
(0 in case of error). |
|
*/ |
|
|
|
ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
|
/* |
|
Converts, formats, and writes the args to the compressed file under |
|
control of the format string, as in fprintf. gzprintf returns the number of |
|
uncompressed bytes actually written (0 in case of error). |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); |
|
/* |
|
Writes the given null-terminated string to the compressed file, excluding |
|
the terminating null character. |
|
gzputs returns the number of characters written, or -1 in case of error. |
|
*/ |
|
|
|
ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); |
|
/* |
|
Reads bytes from the compressed file until len-1 characters are read, or |
|
a newline character is read and transferred to buf, or an end-of-file |
|
condition is encountered. The string is then terminated with a null |
|
character. |
|
gzgets returns buf, or Z_NULL in case of error. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
|
/* |
|
Writes c, converted to an unsigned char, into the compressed file. |
|
gzputc returns the value that was written, or -1 in case of error. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
|
/* |
|
Reads one byte from the compressed file. gzgetc returns this byte |
|
or -1 in case of end of file or error. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
|
/* |
|
Flushes all pending output into the compressed file. The parameter |
|
flush is as in the deflate() function. The return value is the zlib |
|
error number (see function gzerror below). gzflush returns Z_OK if |
|
the flush parameter is Z_FINISH and all output could be flushed. |
|
gzflush should be called only when strictly necessary because it can |
|
degrade compression. |
|
*/ |
|
|
|
ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
|
z_off_t offset, int whence)); |
|
/* |
|
Sets the starting position for the next gzread or gzwrite on the |
|
given compressed file. The offset represents a number of bytes in the |
|
uncompressed data stream. The whence parameter is defined as in lseek(2); |
|
the value SEEK_END is not supported. |
|
If the file is opened for reading, this function is emulated but can be |
|
extremely slow. If the file is opened for writing, only forward seeks are |
|
supported; gzseek then compresses a sequence of zeroes up to the new |
|
starting position. |
|
|
|
gzseek returns the resulting offset location as measured in bytes from |
|
the beginning of the uncompressed stream, or -1 in case of error, in |
|
particular if the file is opened for writing and the new starting position |
|
would be before the current position. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); |
|
/* |
|
Rewinds the given file. This function is supported only for reading. |
|
|
|
gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
|
*/ |
|
|
|
ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
|
/* |
|
Returns the starting position for the next gzread or gzwrite on the |
|
given compressed file. This position represents a number of bytes in the |
|
uncompressed data stream. |
|
|
|
gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzeof OF((gzFile file)); |
|
/* |
|
Returns 1 when EOF has previously been detected reading the given |
|
input stream, otherwise zero. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
|
/* |
|
Flushes all pending output if necessary, closes the compressed file |
|
and deallocates all the (de)compression state. The return value is the zlib |
|
error number (see function gzerror below). |
|
*/ |
|
|
|
ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); |
|
/* |
|
Returns the error message for the last error which occurred on the |
|
given compressed file. errnum is set to zlib error number. If an |
|
error occurred in the file system and not in the compression library, |
|
errnum is set to Z_ERRNO and the application may consult errno |
|
to get the exact error code. |
|
*/ |
|
|
|
/* checksum functions */ |
|
|
|
/* |
|
These functions are not related to compression but are exported |
|
anyway because they might be useful in applications using the |
|
compression library. |
|
*/ |
|
|
|
ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
|
|
|
/* |
|
Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
|
return the updated checksum. If buf is NULL, this function returns |
|
the required initial value for the checksum. |
|
An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
|
much faster. Usage example: |
|
|
|
uLong adler = adler32(0L, Z_NULL, 0); |
|
|
|
while (read_buffer(buffer, length) != EOF) { |
|
adler = adler32(adler, buffer, length); |
|
} |
|
if (adler != original_adler) error(); |
|
*/ |
|
|
|
ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
|
/* |
|
Update a running crc with the bytes buf[0..len-1] and return the updated |
|
crc. If buf is NULL, this function returns the required initial value |
|
for the crc. Pre- and post-conditioning (one's complement) is performed |
|
within this function so it shouldn't be done by the application. |
|
Usage example: |
|
|
|
uLong crc = crc32(0L, Z_NULL, 0); |
|
|
|
while (read_buffer(buffer, length) != EOF) { |
|
crc = crc32(crc, buffer, length); |
|
} |
|
if (crc != original_crc) error(); |
|
*/ |
|
|
|
|
|
/* various hacks, don't look :) */ |
|
|
|
/* deflateInit and inflateInit are macros to allow checking the zlib version |
|
* and the compiler's view of z_stream: |
|
*/ |
|
ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, |
|
const char *version, int stream_size)); |
|
ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, |
|
const char *version, int stream_size)); |
|
ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, |
|
int windowBits, int memLevel, |
|
int strategy, const char *version, |
|
int stream_size)); |
|
ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, |
|
const char *version, int stream_size)); |
|
#define deflateInit(strm, level) \ |
|
deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) |
|
#define inflateInit(strm) \ |
|
inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) |
|
#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ |
|
deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ |
|
(strategy), ZLIB_VERSION, sizeof(z_stream)) |
|
#define inflateInit2(strm, windowBits) \ |
|
inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
|
|
|
|
|
#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) |
|
struct internal_state {int dummy;}; /* hack for buggy compilers */ |
|
#endif |
|
|
|
ZEXTERN const char * ZEXPORT zError OF((int err)); |
|
ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); |
|
ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
|
|
|
#ifdef __cplusplus |
|
} |
|
#endif |
|
|
|
#endif /* _ZLIB_H */
|
|
|