0,0 → 1,893 |
/* zlib.h -- interface of the 'zlib' general purpose compression library |
version 1.1.3, July 9th, 1998 |
|
Copyright (C) 1995-1998 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 ftp://ds.internic.net/rfc/rfc1950.txt |
(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). |
*/ |
|
#ifndef _ZLIB_H |
#define _ZLIB_H |
|
#include "zconf.h" |
|
#ifdef __cplusplus |
extern "C" { |
#endif |
|
#define ZLIB_VERSION "1.1.3" |
|
/* |
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 library also supports reading and writing files in gzip (.gz) format |
with an interface similar to that of stdio. |
|
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. |
*/ |
|
typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
typedef void (*free_func) OF((voidpf opaque, voidpf address)); |
|
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 */ |
voidpf opaque; /* private data object passed to zalloc and zfree */ |
|
int data_type; /* best guess about the data type: ascii or binary */ |
uLong adler; /* adler32 value of the uncompressed data */ |
uLong reserved; /* reserved for future use */ |
} z_stream; |
|
typedef z_stream FAR *z_streamp; |
|
/* |
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 |
/* Allowed flush values; see deflate() 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_DEFAULT_STRATEGY 0 |
/* compression strategy; see deflateInit2() below for details */ |
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#define Z_BINARY 0 |
#define Z_ASCII 1 |
#define Z_UNKNOWN 2 |
/* Possible values of the data_type field */ |
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#define Z_DEFLATED 8 |
/* 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() |
/* for compatibility with versions < 1.0.2 */ |
|
/* basic functions */ |
|
ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
/* The application can compare zlibVersion 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. |
This check is automatically made by deflateInit and inflateInit. |
*/ |
|
/* |
ZEXTERN int ZEXPORT deflateInit OF((z_streamp 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 0 and 9: |
1 gives best speed, 9 gives best compression, 0 gives no compression at |
all (the input data is simply copied a block at a time). |
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, |
Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
with the version assumed by the caller (ZLIB_VERSION). |
msg is set to null if there is no error message. deflateInit does not |
perform any compression: this will be done by deflate(). |
*/ |
|
|
ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
/* |
deflate compresses as much data as possible, and stops when the input |
buffer becomes empty or the output buffer becomes full. It may introduce some |
output latency (reading input without producing any output) except when |
forced to flush. |
|
The detailed semantics are as follows. deflate 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 deflate returns Z_OK |
and with zero avail_out, it must be called again after making room in the |
output buffer because there might be more output pending. |
|
If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
flushed to the output buffer and the output is aligned on a byte boundary, so |
that the decompressor can get all input data available so far. (In particular |
avail_in is zero after the call if enough output space has been provided |
before the call.) Flushing may degrade compression for some compression |
algorithms and so it should be used only when necessary. |
|
If flush is set to Z_FULL_FLUSH, all output is flushed as with |
Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
restart from this point if previous compressed data has been damaged or if |
random access is desired. 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_FINISH, pending input is processed, |
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() sets strm->adler to the adler32 checksum of all input read |
so far (that is, total_in bytes). |
|
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 |
(for example avail_in or avail_out was zero). |
*/ |
|
|
ZEXTERN int ZEXPORT deflateEnd OF((z_streamp 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, Z_DATA_ERROR if the stream was freed |
prematurely (some input or output was discarded). In the error case, |
msg may be set but then points to a static string (which must not be |
deallocated). |
*/ |
|
|
/* |
ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
|
Initializes the internal stream state for decompression. The fields |
next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
the caller. If next_in is not Z_NULL and avail_in is large enough (the exact |
value depends on the compression method), inflateInit determines the |
compression method from the zlib header and allocates all data structures |
accordingly; otherwise the allocation will be deferred to the first call of |
inflate. 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, Z_VERSION_ERROR if the zlib library version is incompatible with the |
version assumed by the caller. msg is set to null if there is no error |
message. inflateInit 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 inflate OF((z_streamp strm, int flush)); |
/* |
inflate decompresses as much data as possible, and stops when the input |
buffer becomes empty or the output buffer becomes full. It may some |
introduce some output latency (reading input without producing any output) |
except when forced to flush. |
|
The detailed semantics are as follows. inflate 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() provides as much output as possible, until there |
is no more input data or no more space in the output buffer (see below |
about the flush parameter). |
|
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 inflate returns Z_OK and with zero avail_out, it |
must be called again after making room in the output buffer because there |
might be more output pending. |
|
If the parameter flush is set to Z_SYNC_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_SYNC_FLUSH |
and Z_FINISH, but the current implementation actually flushes as much output |
as possible anyway. |
|
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. |
|
If a preset dictionary is needed at this point (see inflateSetDictionary |
below), inflate sets strm-adler to the adler32 checksum of the |
dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise |
it sets strm->adler to the adler32 checksum of all output produced |
so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or |
an error code as described below. At the end of the stream, inflate() |
checks that its computed adler32 checksum is equal to that saved by the |
compressor and returns Z_STREAM_END only if the checksum is correct. |
|
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_NEED_DICT if a |
preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
corrupted (input stream not conforming to the zlib format or incorrect |
adler32 checksum), 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. |
*/ |
|
|
ZEXTERN int ZEXPORT inflateEnd OF((z_streamp 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. |
*/ |
|
/* |
ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp 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, zfree and opaque must be initialized before by |
the caller. |
|
The method parameter is the compression method. It must be Z_DEFLATED in |
this version of the library. |
|
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. 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 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. 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.) |
|
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 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. 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. |
|
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 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 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 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. |
*/ |
|
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 0.1% larger than sourceLen plus |
12 bytes. 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 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. |
*/ |
|
|
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". (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, |
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). |
*/ |
|
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). |
*/ |
|
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 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. |
*/ |
|
/* 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)); |
#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 |
|
ZEXTERN const char * ZEXPORT zError OF((int err)); |
ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); |
ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
|
#ifdef __cplusplus |
} |
#endif |
|
#endif /* _ZLIB_H */ |