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1200 lines
56 KiB
1200 lines
56 KiB
/* zlib.h -- interface of the 'zlib' general purpose compression library |
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version 1.2.1.2, September 9th, 2004 |
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Copyright (C) 1995-2004 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 http://www.ietf.org/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 "1.2.1.2" |
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#define ZLIB_VERNUM 0x1212 |
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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 compressed data format used by the in-memory functions is the zlib |
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format, which is a zlib wrapper documented in RFC 1950, wrapped around a |
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deflate stream, which is itself documented in RFC 1951. |
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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 using the functions that start |
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with "gz". The gzip format is different from the zlib format. gzip is a |
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gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. |
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The zlib format was designed to be compact and fast for use in memory |
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and on communications channels. The gzip format was designed for single- |
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file compression on file systems, has a larger header than zlib to maintain |
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directory information, and uses a different, slower check method than zlib. |
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This library does not provide any functions to write gzip files in memory. |
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However such functions could be easily written using zlib's deflate function, |
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the documentation in the gzip RFC, and the examples in gzio.c. |
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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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#define Z_BLOCK 5 |
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/* Allowed flush values; see deflate() and inflate() 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_RLE 3 |
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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 (though see inflate()) */ |
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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). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
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avail_out is greater than six to avoid repeated flush markers due to |
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avail_out == 0 on return. |
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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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the value returned by deflateBound (see below). 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). Note that Z_BUF_ERROR is not |
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fatal, and deflate() can be called again with more input and more output |
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space to continue compressing. |
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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 introduce |
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some 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. 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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The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, |
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Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much |
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output as possible to the output buffer. Z_BLOCK requests that inflate() stop |
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if and when it get to the next deflate block boundary. When decoding the zlib |
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or gzip format, this will cause inflate() to return immediately after the |
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header and before the first block. When doing a raw inflate, inflate() will |
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go ahead and process the first block, and will return when it gets to the end |
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of that block, or when it runs out of data. |
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The Z_BLOCK option assists in appending to or combining deflate streams. |
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Also to assist in this, on return inflate() will set strm->data_type to the |
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number of unused bits in the last byte taken from strm->next_in, plus 64 |
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if inflate() is currently decoding the last block in the deflate stream, |
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plus 128 if inflate() returned immediately after decoding an end-of-block |
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code or decoding the complete header up to just before the first byte of the |
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deflate stream. The end-of-block will not be indicated until all of the |
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uncompressed data from that block has been written to strm->next_out. The |
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number of unused bits may in general be greater than seven, except when |
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bit 7 of data_type is set, in which case the number of unused bits will be |
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less than eight. |
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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 approach |
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may be used for the single inflate() call. |
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In this implementation, inflate() always flushes as much output as |
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possible to the output buffer, and always uses the faster approach on the |
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first call. So the only effect of the flush parameter in this implementation |
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is on the return value of inflate(), as noted below, or when it returns early |
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because Z_BLOCK is used. |
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If a preset dictionary is needed after this call (see inflateSetDictionary |
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below), inflate sets strm->adler to the adler32 checksum of the dictionary |
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chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
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strm->adler to the adler32 checksum of all output produced so far (that is, |
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total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described |
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below. At the end of the stream, inflate() checks that its computed adler32 |
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checksum is equal to that saved by the compressor and returns Z_STREAM_END |
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only if the checksum is correct. |
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inflate() will decompress and check either zlib-wrapped or gzip-wrapped |
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deflate data. The header type is detected automatically. Any information |
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contained in the gzip header is not retained, so applications that need that |
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information should instead use raw inflate, see inflateInit2() below, or |
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inflateBack() and perform their own processing of the gzip header and |
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trailer. |
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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 check |
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value), Z_STREAM_ERROR if the stream structure was inconsistent (for example |
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if 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 the |
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output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
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inflate() can be called again with more input and more output space to |
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continue decompressing. If Z_DATA_ERROR is returned, the application may then |
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call inflateSync() to look for a good compression block if a partial recovery |
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of the data is desired. |
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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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/* |
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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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|
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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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windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
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determines the window size. deflate() will then generate raw deflate data |
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with no zlib header or trailer, and will not compute an adler32 check value. |
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|
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windowBits can also be greater than 15 for optional gzip encoding. Add |
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16 to windowBits to write a simple gzip header and trailer around the |
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compressed data instead of a zlib wrapper. The gzip header will have no |
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file name, no extra data, no comment, no modification time (set to zero), |
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no header crc, and the operating system will be set to 255 (unknown). |
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|
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The memLevel parameter specifies how much memory should be allocated |
|
for the internal compression state. memLevel=1 uses minimum memory but |
|
is slow and reduces compression ratio; memLevel=9 uses maximum memory |
|
for optimal speed. The default value is 8. See zconf.h for total memory |
|
usage as a function of windowBits and memLevel. |
|
|
|
The strategy parameter is used to tune the compression algorithm. Use the |
|
value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
|
filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no |
|
string match), or Z_RLE to limit match distances to one (run-length |
|
encoding). Filtered data consists mostly of small values with a somewhat |
|
random distribution. In this case, the compression algorithm is tuned to |
|
compress them better. The effect of Z_FILTERED is to force more Huffman |
|
coding and less string matching; it is somewhat intermediate between |
|
Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as |
|
Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy |
|
parameter only affects the compression ratio but not the correctness of the |
|
compressed output even if it is not set appropriately. |
|
|
|
deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
|
memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
|
method). msg is set to null if there is no error message. deflateInit2 does |
|
not perform any compression: this will be done by deflate(). |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
|
const Bytef *dictionary, |
|
uInt dictLength)); |
|
/* |
|
Initializes the compression dictionary from the given byte sequence |
|
without producing any compressed output. This function must be called |
|
immediately after deflateInit, deflateInit2 or deflateReset, before any |
|
call of deflate. The compressor and decompressor must use exactly the same |
|
dictionary (see inflateSetDictionary). |
|
|
|
The dictionary should consist of strings (byte sequences) that are likely |
|
to be encountered later in the data to be compressed, with the most commonly |
|
used strings preferably put towards the end of the dictionary. Using a |
|
dictionary is most useful when the data to be compressed is short and can be |
|
predicted with good accuracy; the data can then be compressed better than |
|
with the default empty dictionary. |
|
|
|
Depending on the size of the compression data structures selected by |
|
deflateInit or deflateInit2, a part of the dictionary may in effect be |
|
discarded, for example if the dictionary is larger than the window size in |
|
deflate or deflate2. Thus the strings most likely to be useful should be |
|
put at the end of the dictionary, not at the front. |
|
|
|
Upon return of this function, strm->adler is set to the adler32 value |
|
of the dictionary; the decompressor may later use this value to determine |
|
which dictionary has been used by the compressor. (The adler32 value |
|
applies to the whole dictionary even if only a subset of the dictionary is |
|
actually used by the compressor.) If a raw deflate was requested, then the |
|
adler32 value is not computed and strm->adler is not set. |
|
|
|
deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
|
parameter is invalid (such as NULL dictionary) or the stream state is |
|
inconsistent (for example if deflate has already been called for this stream |
|
or if the compression method is bsort). deflateSetDictionary does not |
|
perform any compression: this will be done by deflate(). |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, |
|
z_streamp source)); |
|
/* |
|
Sets the destination stream as a complete copy of the source stream. |
|
|
|
This function can be useful when several compression strategies will be |
|
tried, for example when there are several ways of pre-processing the input |
|
data with a filter. The streams that will be discarded should then be freed |
|
by calling deflateEnd. Note that deflateCopy duplicates the internal |
|
compression state which can be quite large, so this strategy is slow and |
|
can consume lots of memory. |
|
|
|
deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
|
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
|
(such as zalloc being 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 uLong ZEXPORT deflateBound OF((z_streamp strm, |
|
uLong sourceLen)); |
|
/* |
|
deflateBound() returns an upper bound on the compressed size after |
|
deflation of sourceLen bytes. It must be called after deflateInit() |
|
or deflateInit2(). This would be used to allocate an output buffer |
|
for deflation in a single pass, and so would be called before deflate(). |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, |
|
int bits, |
|
int value)); |
|
/* |
|
deflatePrime() inserts bits in the deflate output stream. The intent |
|
is that this function is used to start off the deflate output with the |
|
bits leftover from a previous deflate stream when appending to it. As such, |
|
this function can only be used for raw deflate, and must be used before the |
|
first deflate() call after a deflateInit2() or deflateReset(). bits must be |
|
less than or equal to 16, and that many of the least significant bits of |
|
value will be inserted in the output. |
|
|
|
deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
|
stream state was inconsistent. |
|
*/ |
|
|
|
/* |
|
ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
|
int windowBits)); |
|
|
|
This is another version of inflateInit with an extra parameter. The |
|
fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
|
before by the caller. |
|
|
|
The windowBits parameter is the base two logarithm of the maximum window |
|
size (the size of the history buffer). It should be in the range 8..15 for |
|
this version of the library. The default value is 15 if inflateInit is used |
|
instead. windowBits must be greater than or equal to the windowBits value |
|
provided to deflateInit2() while compressing, or it must be equal to 15 if |
|
deflateInit2() was not used. If a compressed stream with a larger window |
|
size is given as input, inflate() will return with the error code |
|
Z_DATA_ERROR instead of trying to allocate a larger window. |
|
|
|
windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
|
determines the window size. inflate() will then process raw deflate data, |
|
not looking for a zlib or gzip header, not generating a check value, and not |
|
looking for any check values for comparison at the end of the stream. This |
|
is for use with other formats that use the deflate compressed data format |
|
such as zip. Those formats provide their own check values. If a custom |
|
format is developed using the raw deflate format for compressed data, it is |
|
recommended that a check value such as an adler32 or a crc32 be applied to |
|
the uncompressed data as is done in the zlib, gzip, and zip formats. For |
|
most applications, the zlib format should be used as is. Note that comments |
|
above on the use in deflateInit2() applies to the magnitude of windowBits. |
|
|
|
windowBits can also be greater than 15 for optional gzip decoding. Add |
|
32 to windowBits to enable zlib and gzip decoding with automatic header |
|
detection, or add 16 to decode only the gzip format (the zlib format will |
|
return a Z_DATA_ERROR). |
|
|
|
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 inflateCopy OF((z_streamp dest, |
|
z_streamp source)); |
|
/* |
|
Sets the destination stream as a complete copy of the source stream. |
|
|
|
This function can be useful when randomly accessing a large stream. The |
|
first pass through the stream can periodically record the inflate state, |
|
allowing restarting inflate at those points when randomly accessing the |
|
stream. |
|
|
|
inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
|
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
|
(such as zalloc being NULL). msg is left unchanged in both source and |
|
destination. |
|
*/ |
|
|
|
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). |
|
*/ |
|
|
|
/* |
|
ZEXTERN int ZEXPORT inflateBackInit OF((z_stream FAR *strm, int windowBits, |
|
unsigned char FAR *window)); |
|
|
|
Initialize the internal stream state for decompression using inflateBack() |
|
calls. The fields zalloc, zfree and opaque in strm must be initialized |
|
before the call. If zalloc and zfree are Z_NULL, then the default library- |
|
derived memory allocation routines are used. windowBits is the base two |
|
logarithm of the window size, in the range 8..15. window is a caller |
|
supplied buffer of that size. Except for special applications where it is |
|
assured that deflate was used with small window sizes, windowBits must be 15 |
|
and a 32K byte window must be supplied to be able to decompress general |
|
deflate streams. |
|
|
|
See inflateBack() for the usage of these routines. |
|
|
|
inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of |
|
the paramaters are invalid, Z_MEM_ERROR if the internal state could not |
|
be allocated, or Z_VERSION_ERROR if the version of the library does not |
|
match the version of the header file. |
|
*/ |
|
|
|
typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); |
|
typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); |
|
|
|
ZEXTERN int ZEXPORT inflateBack OF((z_stream FAR *strm, |
|
in_func in, void FAR *in_desc, |
|
out_func out, void FAR *out_desc)); |
|
/* |
|
inflateBack() does a raw inflate with a single call using a call-back |
|
interface for input and output. This is more efficient than inflate() for |
|
file i/o applications in that it avoids copying between the output and the |
|
sliding window by simply making the window itself the output buffer. This |
|
function trusts the application to not change the output buffer passed by |
|
the output function, at least until inflateBack() returns. |
|
|
|
inflateBackInit() must be called first to allocate the internal state |
|
and to initialize the state with the user-provided window buffer. |
|
inflateBack() may then be used multiple times to inflate a complete, raw |
|
deflate stream with each call. inflateBackEnd() is then called to free |
|
the allocated state. |
|
|
|
A raw deflate stream is one with no zlib or gzip header or trailer. |
|
This routine would normally be used in a utility that reads zip or gzip |
|
files and writes out uncompressed files. The utility would decode the |
|
header and process the trailer on its own, hence this routine expects |
|
only the raw deflate stream to decompress. This is different from the |
|
normal behavior of inflate(), which expects either a zlib or gzip header and |
|
trailer around the deflate stream. |
|
|
|
inflateBack() uses two subroutines supplied by the caller that are then |
|
called by inflateBack() for input and output. inflateBack() calls those |
|
routines until it reads a complete deflate stream and writes out all of the |
|
uncompressed data, or until it encounters an error. The function's |
|
parameters and return types are defined above in the in_func and out_func |
|
typedefs. inflateBack() will call in(in_desc, &buf) which should return the |
|
number of bytes of provided input, and a pointer to that input in buf. If |
|
there is no input available, in() must return zero--buf is ignored in that |
|
case--and inflateBack() will return a buffer error. inflateBack() will call |
|
out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() |
|
should return zero on success, or non-zero on failure. If out() returns |
|
non-zero, inflateBack() will return with an error. Neither in() nor out() |
|
are permitted to change the contents of the window provided to |
|
inflateBackInit(), which is also the buffer that out() uses to write from. |
|
The length written by out() will be at most the window size. Any non-zero |
|
amount of input may be provided by in(). |
|
|
|
For convenience, inflateBack() can be provided input on the first call by |
|
setting strm->next_in and strm->avail_in. If that input is exhausted, then |
|
in() will be called. Therefore strm->next_in must be initialized before |
|
calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called |
|
immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in |
|
must also be initialized, and then if strm->avail_in is not zero, input will |
|
initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
|
|
|
The in_desc and out_desc parameters of inflateBack() is passed as the |
|
first parameter of in() and out() respectively when they are called. These |
|
descriptors can be optionally used to pass any information that the caller- |
|
supplied in() and out() functions need to do their job. |
|
|
|
On return, inflateBack() will set strm->next_in and strm->avail_in to |
|
pass back any unused input that was provided by the last in() call. The |
|
return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR |
|
if in() or out() returned an error, Z_DATA_ERROR if there was a format |
|
error in the deflate stream (in which case strm->msg is set to indicate the |
|
nature of the error), or Z_STREAM_ERROR if the stream was not properly |
|
initialized. In the case of Z_BUF_ERROR, an input or output error can be |
|
distinguished using strm->next_in which will be Z_NULL only if in() returned |
|
an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to |
|
out() returning non-zero. (in() will always be called before out(), so |
|
strm->next_in is assured to be defined if out() returns non-zero.) Note |
|
that inflateBack() cannot return Z_OK. |
|
*/ |
|
|
|
ZEXTERN int ZEXPORT inflateBackEnd OF((z_stream FAR *strm)); |
|
/* |
|
All memory allocated by inflateBackInit() is freed. |
|
|
|
inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream |
|
state was inconsistent. |
|
*/ |
|
|
|
ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); |
|
/* Return flags indicating compile-time options. |
|
|
|
Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: |
|
1.0: size of uInt |
|
3.2: size of uLong |
|
5.4: size of voidpf (pointer) |
|
7.6: size of z_off_t |
|
|
|
Compiler, assembler, and debug options: |
|
8: DEBUG |
|
9: ASMV or ASMINF -- use ASM code |
|
10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention |
|
11: 0 (reserved) |
|
|
|
One-time table building (smaller code, but not thread-safe if true): |
|
12: BUILDFIXED -- build static block decoding tables when needed |
|
13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed |
|
14,15: 0 (reserved) |
|
|
|
Library content (indicates missing functionality): |
|
16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking |
|
deflate code when not needed) |
|
17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect |
|
and decode gzip streams (to avoid linking crc code) |
|
18-19: 0 (reserved) |
|
|
|
Operation variations (changes in library functionality): |
|
20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate |
|
21: FASTEST -- deflate algorithm with only one, lowest compression level |
|
22,23: 0 (reserved) |
|
|
|
The sprintf variant used by gzprintf (zero is best): |
|
24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format |
|
25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! |
|
26: 0 = returns value, 1 = void -- 1 means inferred string length returned |
|
|
|
Remainder: |
|
27-31: 0 (reserved) |
|
*/ |
|
|
|
|
|
/* 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 the value returned |
|
by compressBound(sourceLen). 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 the value returned by |
|
compressBound(sourceLen). 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 uLong ZEXPORT compressBound OF((uLong sourceLen)); |
|
/* |
|
compressBound() returns an upper bound on the compressed size after |
|
compress() or compress2() on sourceLen bytes. It would be used before |
|
a compress() or compress2() call to allocate the destination buffer. |
|
*/ |
|
|
|
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 or incomplete. |
|
*/ |
|
|
|
|
|
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", or 'R' for run-length encoding |
|
as in "wb1R". (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, |
|
voidpc 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). The number of |
|
uncompressed bytes written is limited to 4095. The caller should assure that |
|
this limit is not exceeded. If it is exceeded, then gzprintf() will return |
|
return an error (0) with nothing written. In this case, there may also be a |
|
buffer overflow with unpredictable consequences, which is possible only if |
|
zlib was compiled with the insecure functions sprintf() or vsprintf() |
|
because the secure snprintf() or vsnprintf() functions were not available. |
|
*/ |
|
|
|
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 gzungetc OF((int c, gzFile file)); |
|
/* |
|
Push one character back onto the stream to be read again later. |
|
Only one character of push-back is allowed. gzungetc() returns the |
|
character pushed, or -1 on failure. gzungetc() will fail if a |
|
character has been pushed but not read yet, or if c is -1. The pushed |
|
character will be discarded if the stream is repositioned with gzseek() |
|
or gzrewind(). |
|
*/ |
|
|
|
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. |
|
*/ |
|
|
|
ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); |
|
/* |
|
Clears the error and end-of-file flags for file. This is analogous to the |
|
clearerr() function in stdio. This is useful for continuing to read a gzip |
|
file that is being written concurrently. |
|
*/ |
|
|
|
/* 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)); |
|
ZEXTERN int ZEXPORT inflateBackInit_ OF((z_stream FAR *strm, int windowBits, |
|
unsigned char FAR *window, |
|
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)) |
|
#define inflateBackInit(strm, windowBits, window) \ |
|
inflateBackInit_((strm), (windowBits), (window), \ |
|
ZLIB_VERSION, sizeof(z_stream)) |
|
|
|
|
|
#if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
|
struct internal_state {int dummy;}; /* hack for buggy compilers */ |
|
#endif |
|
|
|
ZEXTERN const char * ZEXPORT zError OF((int)); |
|
ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); |
|
ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
|
|
|
#ifdef __cplusplus |
|
} |
|
#endif |
|
|
|
#endif /* ZLIB_H */
|
|
|