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lib/zlib.c
4601
lib/zlib.c
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lib/zlib.h
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lib/zlib.h
@@ -1,632 +0,0 @@
|
||||
/* $Id$ */
|
||||
|
||||
/*
|
||||
* This file is derived from zlib.h and zconf.h from the zlib-0.95
|
||||
* distribution by Jean-loup Gailly and Mark Adler, with some additions
|
||||
* by Paul Mackerras to aid in implementing Deflate compression and
|
||||
* decompression for PPP packets.
|
||||
*/
|
||||
|
||||
/* zlib.h -- interface of the 'zlib' general purpose compression library
|
||||
version 0.95, Aug 16th, 1995.
|
||||
|
||||
Copyright (C) 1995 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
|
||||
gzip@prep.ai.mit.edu madler@alumni.caltech.edu
|
||||
*/
|
||||
|
||||
#ifndef _ZLIB_H
|
||||
#define _ZLIB_H
|
||||
|
||||
/* #include "zconf.h" */ /* included directly here */
|
||||
|
||||
/* zconf.h -- configuration of the zlib compression library
|
||||
* Copyright (C) 1995 Jean-loup Gailly.
|
||||
* For conditions of distribution and use, see copyright notice in zlib.h
|
||||
*/
|
||||
|
||||
/* From: zconf.h,v 1.12 1995/05/03 17:27:12 jloup Exp */
|
||||
|
||||
/*
|
||||
The library does not install any signal handler. It is recommended to
|
||||
add at least a handler for SIGSEGV when decompressing; the library checks
|
||||
the consistency of the input data whenever possible but may go nuts
|
||||
for some forms of corrupted input.
|
||||
*/
|
||||
|
||||
/*
|
||||
* Compile with -DMAXSEG_64K if the alloc function cannot allocate more
|
||||
* than 64k bytes at a time (needed on systems with 16-bit int).
|
||||
* Compile with -DUNALIGNED_OK if it is OK to access shorts or ints
|
||||
* at addresses which are not a multiple of their size.
|
||||
* Under DOS, -DFAR=far or -DFAR=__far may be needed.
|
||||
*/
|
||||
|
||||
#ifndef STDC
|
||||
# if defined(MSDOS) || defined(__STDC__) || defined(__cplusplus)
|
||||
# define STDC
|
||||
# endif
|
||||
#endif
|
||||
|
||||
#ifdef __MWERKS__ /* Metrowerks CodeWarrior declares fileno() in unix.h */
|
||||
# include <unix.h>
|
||||
#endif
|
||||
|
||||
/* Maximum value for memLevel in deflateInit2 */
|
||||
#ifndef MAX_MEM_LEVEL
|
||||
# ifdef MAXSEG_64K
|
||||
# define MAX_MEM_LEVEL 8
|
||||
# else
|
||||
# define MAX_MEM_LEVEL 9
|
||||
# endif
|
||||
#endif
|
||||
|
||||
#ifndef FAR
|
||||
# define FAR
|
||||
#endif
|
||||
|
||||
/* Maximum value for windowBits in deflateInit2 and inflateInit2 */
|
||||
#ifndef MAX_WBITS
|
||||
# define MAX_WBITS 15 /* 32K LZ77 window */
|
||||
#endif
|
||||
|
||||
/* The memory requirements for deflate are (in bytes):
|
||||
1 << (windowBits+2) + 1 << (memLevel+9)
|
||||
that is: 128K for windowBits=15 + 128K for memLevel = 8 (default values)
|
||||
plus a few kilobytes for small objects. For example, if you want to reduce
|
||||
the default memory requirements from 256K to 128K, compile with
|
||||
make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
|
||||
Of course this will generally degrade compression (there's no free lunch).
|
||||
|
||||
The memory requirements for inflate are (in bytes) 1 << windowBits
|
||||
that is, 32K for windowBits=15 (default value) plus a few kilobytes
|
||||
for small objects.
|
||||
*/
|
||||
|
||||
/* Type declarations */
|
||||
|
||||
#ifndef OF /* function prototypes */
|
||||
# ifdef STDC
|
||||
# define OF(args) args
|
||||
# else
|
||||
# define OF(args) ()
|
||||
# endif
|
||||
#endif
|
||||
|
||||
typedef unsigned char Byte; /* 8 bits */
|
||||
typedef unsigned int uInt; /* 16 bits or more */
|
||||
typedef int32 Long; /* 32 bits or more */
|
||||
typedef uint32 uLong; /* 32 bits or more */
|
||||
|
||||
typedef Byte FAR Bytef;
|
||||
typedef char FAR charf;
|
||||
typedef int FAR intf;
|
||||
typedef uInt FAR uIntf;
|
||||
typedef uLong FAR uLongf;
|
||||
|
||||
#ifdef STDC
|
||||
typedef void FAR *voidpf;
|
||||
typedef void *voidp;
|
||||
#else
|
||||
typedef Byte FAR *voidpf;
|
||||
typedef Byte *voidp;
|
||||
#endif
|
||||
|
||||
/* end of original zconf.h */
|
||||
|
||||
#define ZLIB_VERSION "0.95P"
|
||||
|
||||
/*
|
||||
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 may be added later and will have the same
|
||||
stream interface.
|
||||
|
||||
For compression the application must provide the output buffer and
|
||||
may optionally provide the input buffer for optimization. For decompression,
|
||||
the application must provide the input buffer and may optionally provide
|
||||
the output buffer for optimization.
|
||||
|
||||
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.
|
||||
*/
|
||||
|
||||
typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
|
||||
typedef void (*free_func) OF((voidpf opaque, voidpf address, uInt nbytes));
|
||||
|
||||
struct internal_state;
|
||||
|
||||
typedef struct z_stream_s {
|
||||
Bytef *next_in; /* next input byte */
|
||||
uInt avail_in; /* number of bytes available at next_in */
|
||||
uLong total_in; /* total nb of input bytes read so far */
|
||||
|
||||
Bytef *next_out; /* next output byte should be put there */
|
||||
uInt avail_out; /* remaining free space at next_out */
|
||||
uLong total_out; /* total nb of bytes output so far */
|
||||
|
||||
char *msg; /* last error message, NULL if no error */
|
||||
struct internal_state FAR *state; /* not visible by applications */
|
||||
|
||||
alloc_func zalloc; /* used to allocate the internal state */
|
||||
free_func zfree; /* used to free the internal state */
|
||||
voidp opaque; /* private data object passed to zalloc and zfree */
|
||||
|
||||
Byte data_type; /* best guess about the data type: ascii or binary */
|
||||
|
||||
} z_stream;
|
||||
|
||||
/*
|
||||
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.
|
||||
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
|
||||
#define Z_FULL_FLUSH 2
|
||||
#define Z_SYNC_FLUSH 3 /* experimental: partial_flush + byte align */
|
||||
#define Z_FINISH 4
|
||||
#define Z_PACKET_FLUSH 5
|
||||
#define Z_INSERT_ONLY 6 /* update hash table etc., produce no output */
|
||||
/* See deflate() below for the usage of these constants */
|
||||
|
||||
#define Z_OK 0
|
||||
#define Z_STREAM_END 1
|
||||
#define Z_ERRNO (-1)
|
||||
#define Z_STREAM_ERROR (-2)
|
||||
#define Z_DATA_ERROR (-3)
|
||||
#define Z_MEM_ERROR (-4)
|
||||
#define Z_BUF_ERROR (-5)
|
||||
/* error codes for the compression/decompression functions */
|
||||
|
||||
#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_DEFAULT_STRATEGY 0
|
||||
|
||||
#define Z_BINARY 0
|
||||
#define Z_ASCII 1
|
||||
#define Z_UNKNOWN 2
|
||||
/* Used to set the data_type field */
|
||||
|
||||
#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
|
||||
|
||||
extern char *zlib_version;
|
||||
/* The application can compare zlib_version and ZLIB_VERSION for consistency.
|
||||
If the first character differs, the library code actually used is
|
||||
not compatible with the zlib.h header file used by the application.
|
||||
*/
|
||||
|
||||
/* basic functions */
|
||||
|
||||
extern int deflateInit OF((z_stream *strm, int level));
|
||||
/*
|
||||
Initializes the internal stream state for compression. The fields
|
||||
zalloc, zfree and opaque must be initialized before by the caller.
|
||||
If zalloc and zfree are set to Z_NULL, deflateInit updates them to
|
||||
use default allocation functions.
|
||||
|
||||
The compression level must be Z_DEFAULT_COMPRESSION, or between 1 and 9:
|
||||
1 gives best speed, 9 gives best compression. Z_DEFAULT_COMPRESSION requests
|
||||
a default compromise between speed and compression (currently equivalent
|
||||
to level 6).
|
||||
|
||||
deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
|
||||
enough memory, Z_STREAM_ERROR if level is not a valid compression level.
|
||||
msg is set to null if there is no error message. deflateInit does not
|
||||
perform any compression: this will be done by deflate().
|
||||
*/
|
||||
|
||||
|
||||
extern int deflate OF((z_stream *strm, int flush));
|
||||
/*
|
||||
Performs one or both of the following actions:
|
||||
|
||||
- Compress more input starting at next_in and update next_in and avail_in
|
||||
accordingly. If not all input can be processed (because there is not
|
||||
enough room in the output buffer), next_in and avail_in are updated and
|
||||
processing will resume at this point for the next call of deflate().
|
||||
|
||||
- Provide more output starting at next_out and update next_out and avail_out
|
||||
accordingly. This action is forced if the parameter flush is non zero.
|
||||
Forcing flush frequently degrades the compression ratio, so this parameter
|
||||
should be set only when necessary (in interactive applications).
|
||||
Some output may be provided even if flush is not set.
|
||||
|
||||
Before the call of deflate(), the application should ensure that at least
|
||||
one of the actions is possible, by providing more input and/or consuming
|
||||
more output, and updating avail_in or avail_out accordingly; avail_out
|
||||
should never be zero before the call. The application can consume the
|
||||
compressed output when it wants, for example when the output buffer is full
|
||||
(avail_out == 0), or after each call of deflate().
|
||||
|
||||
If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression
|
||||
block is terminated and flushed to the output buffer so that the
|
||||
decompressor can get all input data available so far. For method 9, a future
|
||||
variant on method 8, the current block will be flushed but not terminated.
|
||||
If flush is set to Z_FULL_FLUSH, the compression block is terminated, a
|
||||
special marker is output and the compression dictionary is discarded; this
|
||||
is useful to allow the decompressor to synchronize if one compressed block
|
||||
has been damaged (see inflateSync below). Flushing degrades compression and
|
||||
so should be used only when necessary. Using Z_FULL_FLUSH too often can
|
||||
seriously degrade the compression. If deflate returns with avail_out == 0,
|
||||
this function must be called again with the same value of the flush
|
||||
parameter and more output space (updated avail_out), until the flush is
|
||||
complete (deflate returns with non-zero avail_out).
|
||||
|
||||
If the parameter flush is set to Z_PACKET_FLUSH, the compression
|
||||
block is terminated, and a zero-length stored block is output,
|
||||
omitting the length bytes (the effect of this is that the 3-bit type
|
||||
code 000 for a stored block is output, and the output is then
|
||||
byte-aligned). This is designed for use at the end of a PPP packet.
|
||||
In addition, if the current compression block contains all the data
|
||||
since the last Z_PACKET_FLUSH, it is never output as a stored block.
|
||||
If the current compression block output as a static or dynamic block
|
||||
would not be at least `minCompression' bytes smaller than the
|
||||
original data, then nothing is output for that block. (The type
|
||||
code for the zero-length stored block is still output, resulting in
|
||||
a single zero byte being output for the whole packet.)
|
||||
`MinCompression' is a parameter to deflateInit2, or 0 if deflateInit
|
||||
is used.
|
||||
|
||||
If the parameter flush is set to Z_FINISH, all pending input is processed,
|
||||
all pending output is flushed and deflate returns with Z_STREAM_END if there
|
||||
was enough output space; if deflate returns with Z_OK, this function must be
|
||||
called again with Z_FINISH and more output space (updated avail_out) but no
|
||||
more input data, until it returns with Z_STREAM_END or an error. After
|
||||
deflate has returned Z_STREAM_END, the only possible operations on the
|
||||
stream are deflateReset or deflateEnd.
|
||||
|
||||
Z_FINISH can be used immediately after deflateInit if all the compression
|
||||
is to be done in a single step. In this case, avail_out must be at least
|
||||
0.1% larger than avail_in plus 12 bytes. If deflate does not return
|
||||
Z_STREAM_END, then it must be called again as described above.
|
||||
|
||||
deflate() may update data_type if it can make a good guess about
|
||||
the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
|
||||
binary. This field is only for information purposes and does not affect
|
||||
the compression algorithm in any manner.
|
||||
|
||||
deflate() returns Z_OK if some progress has been made (more input
|
||||
processed or more output produced), Z_STREAM_END if all input has been
|
||||
consumed and all output has been produced (only when flush is set to
|
||||
Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
|
||||
if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible.
|
||||
*/
|
||||
|
||||
|
||||
extern int deflateEnd OF((z_stream *strm));
|
||||
/*
|
||||
All dynamically allocated data structures for this stream are freed.
|
||||
This function discards any unprocessed input and does not flush any
|
||||
pending output.
|
||||
|
||||
deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
|
||||
stream state was inconsistent. In the error case, msg may be set
|
||||
but then points to a static string (which must not be deallocated).
|
||||
*/
|
||||
|
||||
|
||||
extern int inflateInit OF((z_stream *strm));
|
||||
/*
|
||||
Initializes the internal stream state for decompression. The fields
|
||||
zalloc and zfree must be initialized before by the caller. If zalloc and
|
||||
zfree are set to Z_NULL, inflateInit updates them to use default allocation
|
||||
functions.
|
||||
|
||||
inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
|
||||
enough memory. msg is set to null if there is no error message.
|
||||
inflateInit does not perform any decompression: this will be done by
|
||||
inflate().
|
||||
*/
|
||||
|
||||
|
||||
extern int inflate OF((z_stream *strm, int flush));
|
||||
/*
|
||||
Performs one or both of the following actions:
|
||||
|
||||
- Decompress more input starting at next_in and update next_in and avail_in
|
||||
accordingly. If not all input can be processed (because there is not
|
||||
enough room in the output buffer), next_in is updated and processing
|
||||
will resume at this point for the next call of inflate().
|
||||
|
||||
- Provide more output starting at next_out and update next_out and avail_out
|
||||
accordingly. inflate() always provides as much output as possible
|
||||
(until there is no more input data or no more space in the output buffer).
|
||||
|
||||
Before the call of inflate(), the application should ensure that at least
|
||||
one of the actions is possible, by providing more input and/or consuming
|
||||
more output, and updating the next_* and avail_* values accordingly.
|
||||
The application can consume the uncompressed output when it wants, for
|
||||
example when the output buffer is full (avail_out == 0), or after each
|
||||
call of inflate().
|
||||
|
||||
If the parameter flush is set to Z_PARTIAL_FLUSH or Z_PACKET_FLUSH,
|
||||
inflate flushes as much output as possible to the output buffer. The
|
||||
flushing behavior of inflate is not specified for values of the flush
|
||||
parameter other than Z_PARTIAL_FLUSH, Z_PACKET_FLUSH or Z_FINISH, but the
|
||||
current implementation actually flushes as much output as possible
|
||||
anyway. For Z_PACKET_FLUSH, inflate checks that once all the input data
|
||||
has been consumed, it is expecting to see the length field of a stored
|
||||
block; if not, it returns Z_DATA_ERROR.
|
||||
|
||||
inflate() should normally be called until it returns Z_STREAM_END or an
|
||||
error. However if all decompression is to be performed in a single step
|
||||
(a single call of inflate), the parameter flush should be set to
|
||||
Z_FINISH. In this case all pending input is processed and all pending
|
||||
output is flushed; avail_out must be large enough to hold all the
|
||||
uncompressed data. (The size of the uncompressed data may have been saved
|
||||
by the compressor for this purpose.) The next operation on this stream must
|
||||
be inflateEnd to deallocate the decompression state. The use of Z_FINISH
|
||||
is never required, but can be used to inform inflate that a faster routine
|
||||
may be used for the single inflate() call.
|
||||
|
||||
inflate() returns Z_OK if some progress has been made (more input
|
||||
processed or more output produced), Z_STREAM_END if the end of the
|
||||
compressed data has been reached and all uncompressed output has been
|
||||
produced, Z_DATA_ERROR if the input data was corrupted, Z_STREAM_ERROR if
|
||||
the stream structure was inconsistent (for example if next_in or next_out
|
||||
was NULL), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if no
|
||||
progress is possible or if there was not enough room in the output buffer
|
||||
when Z_FINISH is used. In the Z_DATA_ERROR case, the application may then
|
||||
call inflateSync to look for a good compression block. */
|
||||
|
||||
|
||||
extern int inflateEnd OF((z_stream *strm));
|
||||
/*
|
||||
All dynamically allocated data structures for this stream are freed.
|
||||
This function discards any unprocessed input and does not flush any
|
||||
pending output.
|
||||
|
||||
inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
|
||||
was inconsistent. In the error case, msg may be set but then points to a
|
||||
static string (which must not be deallocated).
|
||||
*/
|
||||
|
||||
/* advanced functions */
|
||||
|
||||
/*
|
||||
The following functions are needed only in some special applications.
|
||||
*/
|
||||
|
||||
extern int deflateInit2 OF((z_stream *strm,
|
||||
int level,
|
||||
int method,
|
||||
int windowBits,
|
||||
int memLevel,
|
||||
int strategy));
|
||||
/*
|
||||
This is another version of deflateInit with more compression options. The
|
||||
fields next_in, zalloc and zfree must be initialized before by the caller.
|
||||
|
||||
The method parameter is the compression method. It must be 8 in this
|
||||
version of the library. (Method 9 will allow a 64K history buffer and
|
||||
partial block flushes.)
|
||||
|
||||
The windowBits parameter is the base two logarithm of the window size
|
||||
(the size of the history buffer). It should be in the range 8..15 for this
|
||||
version of the library (the value 16 will be allowed for method 9). Larger
|
||||
values of this parameter result in better compression at the expense of
|
||||
memory usage. The default value is 15 if deflateInit is used instead.
|
||||
|
||||
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), or Z_HUFFMAN_ONLY to force Huffman
|
||||
encoding only (no string match). 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 strategy
|
||||
parameter only affects the compression ratio but not the correctness of
|
||||
the compressed output even if it is not set appropriately.
|
||||
|
||||
The minCompression parameter specifies the minimum reduction in size
|
||||
required for a compressed block to be output when Z_PACKET_FLUSH is
|
||||
used (see the description of deflate above).
|
||||
|
||||
If next_in is not null, the library will use this buffer to hold also
|
||||
some history information; the buffer must either hold the entire input
|
||||
data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in
|
||||
is null, the library will allocate its own history buffer (and leave next_in
|
||||
null). next_out need not be provided here but must be provided by the
|
||||
application for the next call of deflate().
|
||||
|
||||
If the history buffer is provided by the application, next_in must
|
||||
must never be changed by the application since the compressor maintains
|
||||
information inside this buffer from call to call; the application
|
||||
must provide more input only by increasing avail_in. next_in is always
|
||||
reset by the library in this case.
|
||||
|
||||
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().
|
||||
*/
|
||||
|
||||
extern int deflateCopy OF((z_stream *dest,
|
||||
z_stream *source));
|
||||
/*
|
||||
Sets the destination stream as a complete copy of the source stream. If
|
||||
the source stream is using an application-supplied history buffer, a new
|
||||
buffer is allocated for the destination stream. The compressed output
|
||||
buffer is always application-supplied. It's the responsibility of the
|
||||
application to provide the correct values of next_out and avail_out for the
|
||||
next call of deflate.
|
||||
|
||||
This function is 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.
|
||||
*/
|
||||
|
||||
extern int deflateReset OF((z_stream *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).
|
||||
*/
|
||||
|
||||
extern int inflateInit2 OF((z_stream *strm,
|
||||
int windowBits));
|
||||
/*
|
||||
This is another version of inflateInit with more compression options. The
|
||||
fields next_out, zalloc and zfree must be initialized before by the caller.
|
||||
|
||||
The windowBits parameter is the base two logarithm of the maximum window
|
||||
size (the size of the history buffer). It should be in the range 8..15 for
|
||||
this version of the library (the value 16 will be allowed soon). The
|
||||
default value is 15 if inflateInit is used instead. If a compressed stream
|
||||
with a larger window size is given as input, inflate() will return with
|
||||
the error code Z_DATA_ERROR instead of trying to allocate a larger window.
|
||||
|
||||
If next_out is not null, the library will use this buffer for the history
|
||||
buffer; the buffer must either be large enough to hold the entire output
|
||||
data, or have at least 1<<windowBits bytes. If next_out is null, the
|
||||
library will allocate its own buffer (and leave next_out null). next_in
|
||||
need not be provided here but must be provided by the application for the
|
||||
next call of inflate().
|
||||
|
||||
If the history buffer is provided by the application, next_out must
|
||||
never be changed by the application since the decompressor maintains
|
||||
history information inside this buffer from call to call; the application
|
||||
can only reset next_out to the beginning of the history buffer when
|
||||
avail_out is zero and all output has been consumed.
|
||||
|
||||
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
|
||||
not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
|
||||
windowBits < 8). msg is set to null if there is no error message.
|
||||
inflateInit2 does not perform any decompression: this will be done by
|
||||
inflate().
|
||||
*/
|
||||
|
||||
extern int inflateSync OF((z_stream *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 inflateReset OF((z_stream *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).
|
||||
*/
|
||||
|
||||
extern int inflateIncomp OF((z_stream *strm));
|
||||
/*
|
||||
This function adds the data at next_in (avail_in bytes) to the output
|
||||
history without performing any output. There must be no pending output,
|
||||
and the decompressor must be expecting to see the start of a block.
|
||||
Calling this function is equivalent to decompressing a stored block
|
||||
containing the data at next_in (except that the data is not output).
|
||||
*/
|
||||
|
||||
/* checksum functions */
|
||||
|
||||
/*
|
||||
This function is not related to compression but is exported
|
||||
anyway because it might be useful in applications using the
|
||||
compression library.
|
||||
*/
|
||||
|
||||
extern uLong adler32 OF((uLong adler, 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();
|
||||
*/
|
||||
|
||||
#ifndef _Z_UTIL_H
|
||||
struct internal_state {int dummy;}; /* hack for buggy compilers */
|
||||
#endif
|
||||
|
||||
#endif /* _ZLIB_H */
|
||||
Reference in New Issue
Block a user