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780 lines
36 KiB
780 lines
36 KiB
/* zlib.h -- interface of the 'zlib' general purpose compression library |
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version 1.0.4, Jul 24th, 1996. |
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Copyright (C) 1995-1996 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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gzip@prep.ai.mit.edu 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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#ifdef __cplusplus |
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extern "C" { |
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#endif |
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#include "zconf.h" |
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#define ZLIB_VERSION "1.0.4" |
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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 may be added later and will have the same |
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stream interface. |
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For compression the application must provide the output buffer and |
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may optionally provide the input buffer for optimization. For decompression, |
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the application must provide the input buffer and may optionally provide |
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the output buffer for optimization. |
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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 does not install any signal handler. It is recommended to |
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add at least a handler for SIGSEGV when decompressing; the library checks |
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the consistency of the input data whenever possible but may go nuts |
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for some forms 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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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 |
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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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extern const char * EXPORT 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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extern int EXPORT 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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extern int EXPORT deflate OF((z_streamp strm, int flush)); |
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/* |
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Performs one or both of the 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_PARTIAL_FLUSH, the current compression |
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block is terminated and flushed to the output buffer so that the |
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decompressor can get all input data available so far. For method 9, a future |
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variant on method 8, the current block will be flushed but not terminated. |
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Z_SYNC_FLUSH has the same effect as partial flush except that the compressed |
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output is byte aligned (the compressor can clear its internal bit buffer) |
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and the current block is always terminated; this can be useful if the |
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compressor has to be restarted from scratch after an interruption (in which |
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case the internal state of the compressor may be lost). |
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If flush is set to Z_FULL_FLUSH, the compression block is terminated, a |
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special marker is output and the compression dictionary is discarded; this |
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is useful to allow the decompressor to synchronize if one compressed block |
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has been damaged (see inflateSync below). Flushing degrades compression and |
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so should be used only when necessary. Using Z_FULL_FLUSH too often can |
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seriously degrade the compression. If deflate returns with avail_out == 0, |
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this function must be called again with the same value of the flush |
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parameter and more output space (updated avail_out), until the flush is |
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complete (deflate returns with non-zero 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() 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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*/ |
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extern int EXPORT 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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extern int EXPORT inflateInit OF((z_streamp strm)); |
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Initializes the internal stream state for decompression. The fields |
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zalloc, zfree and opaque must be initialized before by the caller. If |
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zalloc and zfree are set to Z_NULL, inflateInit updates them to use default |
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allocation functions. |
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inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
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enough memory, Z_VERSION_ERROR if the zlib library version is incompatible |
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with the version assumed by the caller. msg is set to null if there is no |
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error message. inflateInit does not perform any decompression: this will be |
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done by inflate(). |
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*/ |
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extern int EXPORT inflate OF((z_streamp strm, int flush)); |
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/* |
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Performs one or both of the 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_PARTIAL_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_PARTIAL_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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inflate() returns Z_OK if some progress has been made (more input |
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processed or more output produced), Z_STREAM_END if the end of the |
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compressed data has been reached and all uncompressed output has been |
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produced, Z_NEED_DICT if a preset dictionary is needed at this point (see |
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inflateSetDictionary below), Z_DATA_ERROR if the input data was corrupted, |
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Z_STREAM_ERROR if the stream structure was inconsistent (for example if |
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next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, |
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Z_BUF_ERROR if no progress is possible or if there was not enough room in |
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the output buffer when Z_FINISH is used. In the Z_DATA_ERROR case, the |
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application may then call inflateSync to look for a good compression block. |
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In the Z_NEED_DICT case, strm->adler is set to the Adler32 value of the |
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dictionary chosen by the compressor. |
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*/ |
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extern int EXPORT 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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extern int EXPORT 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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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. (Method 9 will allow a 64K history buffer and |
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partial block flushes.) |
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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 (the value 16 will be allowed for method 9). Larger |
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values of this parameter result in better compression at the expense of |
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memory usage. The default value is 15 if deflateInit is used instead. |
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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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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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If next_in is not null, the library will use this buffer to hold also |
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some history information; the buffer must either hold the entire input |
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data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in |
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is null, the library will allocate its own history buffer (and leave next_in |
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null). next_out need not be provided here but must be provided by the |
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application for the next call of deflate(). |
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If the history buffer is provided by the application, next_in must |
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must never be changed by the application since the compressor maintains |
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information inside this buffer from call to call; the application |
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must provide more input only by increasing avail_in. next_in is always |
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reset by the library in this case. |
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deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was |
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not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as |
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an invalid method). msg is set to null if there is no error message. |
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deflateInit2 does not perform any compression: this will be done by |
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deflate(). |
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*/ |
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extern int EXPORT 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 (history buffer) from the given |
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byte sequence without producing any compressed output. This function must |
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be called immediately after deflateInit or deflateInit2, before any call |
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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 |
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can be predicted with good accuracy; the data can then be compressed better |
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than with the default empty dictionary. In this version of the library, |
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only the last 32K bytes of the dictionary are used. |
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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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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 |
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is inconsistent (for example if deflate has already been called for this |
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stream). deflateSetDictionary does not perform any compression: this will |
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be done by deflate(). |
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*/ |
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extern int EXPORT 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. If |
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the source stream is using an application-supplied history buffer, a new |
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buffer is allocated for the destination stream. The compressed output |
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buffer is always application-supplied. It's the responsibility of the |
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application to provide the correct values of next_out and avail_out for the |
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next call of deflate. |
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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 |
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(such as zalloc being NULL). msg is left unchanged in both source and |
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destination. |
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*/ |
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extern int EXPORT deflateReset OF((z_streamp strm)); |
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/* |
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This function is equivalent to deflateEnd followed by deflateInit, |
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but does not free and reallocate all the internal compression state. |
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The stream will keep the same compression level and any other attributes |
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that may have been set by deflateInit2. |
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|
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deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
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stream state was inconsistent (such as zalloc or state being NULL). |
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*/ |
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extern int EXPORT deflateParams OF((z_streamp strm, int level, int strategy)); |
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/* |
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Dynamically update the compression level and compression strategy. |
|
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. |
|
*/ |
|
|
|
/* |
|
extern int EXPORT inflateInit2 OF((z_streamp strm, |
|
int windowBits)); |
|
|
|
This is another version of inflateInit with more compression options. The |
|
fields next_out, 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 value 16 will be allowed soon). 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. |
|
|
|
If next_out is not null, the library will use this buffer for the history |
|
buffer; the buffer must either be large enough to hold the entire output |
|
data, or have at least 1<<windowBits bytes. If next_out is null, the |
|
library will allocate its own buffer (and leave next_out null). next_in |
|
need not be provided here but must be provided by the application for the |
|
next call of inflate(). |
|
|
|
If the history buffer is provided by the application, next_out must |
|
never be changed by the application since the decompressor maintains |
|
history information inside this buffer from call to call; the application |
|
can only reset next_out to the beginning of the history buffer when |
|
avail_out is zero and all output has been consumed. |
|
|
|
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 |
|
windowBits < 8). msg is set to null if there is no error message. |
|
inflateInit2 does not perform any decompression: this will be done by |
|
inflate(). |
|
*/ |
|
|
|
extern int EXPORT inflateSetDictionary OF((z_streamp strm, |
|
const Bytef *dictionary, |
|
uInt dictLength)); |
|
/* |
|
Initializes the decompression dictionary (history buffer) 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(). |
|
*/ |
|
|
|
extern int EXPORT inflateSync OF((z_streamp strm)); |
|
/* |
|
Skips invalid compressed data until the special marker (see deflate() |
|
above) can be found, or until all available input is skipped. No output |
|
is provided. |
|
|
|
inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR |
|
if no more input was provided, Z_DATA_ERROR if no marker 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. |
|
*/ |
|
|
|
extern int EXPORT 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, window size, |
|
standard memory allocation functions). The source code of these |
|
utility functions can easily be modified if you need special options. |
|
*/ |
|
|
|
extern int EXPORT 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. |
|
*/ |
|
|
|
extern int EXPORT 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; |
|
|
|
extern gzFile EXPORT 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"). 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). |
|
*/ |
|
|
|
extern gzFile EXPORT 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. |
|
*/ |
|
|
|
extern int EXPORT 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). */ |
|
|
|
extern int EXPORT 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). |
|
*/ |
|
|
|
extern int EXPORT 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. |
|
*/ |
|
|
|
extern int EXPORT 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). |
|
*/ |
|
|
|
extern const char * EXPORT 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. |
|
*/ |
|
|
|
extern uLong EXPORT 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(); |
|
*/ |
|
|
|
extern uLong EXPORT 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: |
|
*/ |
|
extern int EXPORT deflateInit_ OF((z_streamp strm, int level, |
|
const char *version, int stream_size)); |
|
extern int EXPORT inflateInit_ OF((z_streamp strm, |
|
const char *version, int stream_size)); |
|
extern int EXPORT deflateInit2_ OF((z_streamp strm, int level, int method, |
|
int windowBits, int memLevel, int strategy, |
|
const char *version, int stream_size)); |
|
extern int EXPORT 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 |
|
|
|
uLongf *get_crc_table OF((void)); /* can be used by asm versions of crc32() */ |
|
|
|
#ifdef __cplusplus |
|
} |
|
#endif |
|
|
|
#endif /* _ZLIB_H */
|
|
|