?? zlib.h
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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 */
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