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- /* zlib.h -- interface of the 'zlib' general purpose compression library
- version 1.2.3, July 18th, 2005
- Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
- This software is provided 'as-is', without any express or implied
- warranty. In no event will the authors be held liable for any damages
- arising from the use of this software.
- Permission is granted to anyone to use this software for any purpose,
- including commercial applications, and to alter it and redistribute it
- freely, subject to the following restrictions:
- 1. The origin of this software must not be misrepresented; you must not
- claim that you wrote the original software. If you use this software
- in a product, an acknowledgment in the product documentation would be
- appreciated but is not required.
- 2. Altered source versions must be plainly marked as such, and must not be
- misrepresented as being the original software.
- 3. This notice may not be removed or altered from any source distribution.
- Jean-loup Gailly Mark Adler
- jloup@gzip.org madler@alumni.caltech.edu
- The data format used by the zlib library is described by RFCs (Request for
- Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
- (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
- */
- #ifndef GZIO_H
- #define GZIO_H
- #ifdef __cplusplus
- extern "C" {
- #endif
- /*
- The 'zlib' compression library provides in-memory compression and
- decompression functions, including integrity checks of the uncompressed
- data. This version of the library supports only one compression method
- (deflation) but other algorithms will be added later and will have the same
- stream interface.
- Compression can be done in a single step if the buffers are large
- enough (for example if an input file is mmap'ed), or can be done by
- repeated calls of the compression function. In the latter case, the
- application must provide more input and/or consume the output
- (providing more output space) before each call.
- The compressed data format used by default by the in-memory functions is
- the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
- around a deflate stream, which is itself documented in RFC 1951.
- The library also supports reading and writing files in gzip (.gz) format
- with an interface similar to that of stdio using the functions that start
- with "gz". The gzip format is different from the zlib format. gzip is a
- gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
- This library can optionally read and write gzip streams in memory as well.
- The zlib format was designed to be compact and fast for use in memory
- and on communications channels. The gzip format was designed for single-
- file compression on file systems, has a larger header than zlib to maintain
- directory information, and uses a different, slower check method than zlib.
- The library does not install any signal handler. The decoder checks
- the consistency of the compressed data, so the library should never
- crash even in case of corrupted input.
- */
- #ifdef STDC
- typedef void const *voidpc;
- #else
- typedef Byte const *voidpc;
- #endif
- /*
- gzip header information passed to and from zlib routines. See RFC 1952
- for more details on the meanings of these fields.
- */
- typedef struct gz_header_s {
- int text; /* true if compressed data believed to be text */
- uLong time; /* modification time */
- int xflags; /* extra flags (not used when writing a gzip file) */
- int os; /* operating system */
- Bytef *extra; /* pointer to extra field or Z_NULL if none */
- uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
- uInt extra_max; /* space at extra (only when reading header) */
- Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
- uInt name_max; /* space at name (only when reading header) */
- Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
- uInt comm_max; /* space at comment (only when reading header) */
- int hcrc; /* true if there was or will be a header crc */
- int done; /* true when done reading gzip header (not used
- when writing a gzip file) */
- } gz_header;
- typedef gz_header FAR *gz_headerp;
- /*
- The application must update next_in and avail_in when avail_in has
- dropped to zero. It must update next_out and avail_out when avail_out
- has dropped to zero. The application must initialize zalloc, zfree and
- opaque before calling the init function. All other fields are set by the
- compression library and must not be updated by the application.
- The opaque value provided by the application will be passed as the first
- parameter for calls of zalloc and zfree. This can be useful for custom
- memory management. The compression library attaches no meaning to the
- opaque value.
- zalloc must return Z_NULL if there is not enough memory for the object.
- If zlib is used in a multi-threaded application, zalloc and zfree must be
- thread safe.
- On 16-bit systems, the functions zalloc and zfree must be able to allocate
- exactly 65536 bytes, but will not be required to allocate more than this
- if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
- pointers returned by zalloc for objects of exactly 65536 bytes *must*
- have their offset normalized to zero. The default allocation function
- provided by this library ensures this (see zutil.c). To reduce memory
- requirements and avoid any allocation of 64K objects, at the expense of
- compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
- The fields total_in and total_out can be used for statistics or
- progress reports. After compression, total_in holds the total size of
- the uncompressed data and may be saved for use in the decompressor
- (particularly if the decompressor wants to decompress everything in
- a single step).
- */
- /* constants */
- #define Z_NO_FLUSH 0
- #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
- #define Z_SYNC_FLUSH 2
- #define Z_FULL_FLUSH 3
- #define Z_FINISH 4
- #define Z_BLOCK 5
- /* Allowed flush values; see deflate() and inflate() below for details */
- #define Z_OK 0
- #define Z_STREAM_END 1
- #define Z_NEED_DICT 2
- #define Z_ERRNO (-1)
- #define Z_STREAM_ERROR (-2)
- #define Z_DATA_ERROR (-3)
- #define Z_MEM_ERROR (-4)
- #define Z_BUF_ERROR (-5)
- #define Z_VERSION_ERROR (-6)
- /* Return codes for the compression/decompression functions. Negative
- * values are errors, positive values are used for special but normal events.
- */
- #define Z_NO_COMPRESSION 0
- #define Z_BEST_SPEED 1
- #define Z_BEST_COMPRESSION 9
- #define Z_DEFAULT_COMPRESSION (-1)
- /* compression levels */
- #define Z_FILTERED 1
- #define Z_HUFFMAN_ONLY 2
- #define Z_RLE 3
- #define Z_FIXED 4
- #define Z_DEFAULT_STRATEGY 0
- /* compression strategy; see deflateInit2() below for details */
- #define Z_BINARY 0
- #define Z_TEXT 1
- //#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
- #define Z_UNKNOWN 2
- /* Possible values of the data_type field (though see inflate()) */
- #define Z_DEFLATED 8
- /* The deflate compression method (the only one supported in this version) */
- #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
- #define zlib_version zlibVersion()
- /* for compatibility with versions < 1.0.2 */
- 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 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 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).
- */
- #ifdef __cplusplus
- } // extern "C"
- #endif
- #endif /* GZIO_H */
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