/* zlib.h -- interface of the 'zlib' general purpose compression library | |
version 1.1.4, March 11th, 2002 | |
Copyright (C) 1995-2002 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 "1.1.4" | |
/* | |
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 */ | |
#define Z_BINARY 0 | |
#define Z_ASCII 1 | |
#define Z_UNKNOWN 2 | |
/* Possible values of the data_type field */ | |
#define Z_DEFLATED 8 | |
/* The deflate compression method (the only one supported in this version) */ | |
#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ | |
/* basic functions */ | |
/* 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) 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(). | |
*/ | |
/* | |
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). | |
*/ | |
/* | |
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) 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) 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) 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) 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(). | |
*/ | |
/* | |
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(). | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
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). | |
*/ | |
/* | |
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) 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.) | |
*/ | |
/* | |
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(). | |
*/ | |
/* | |
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) 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. | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
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). */ | |
/* | |
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. | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
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). */ | |
/* | |
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). | |
*/ | |
/* | |
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). | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
Writes c, converted to an unsigned char, into the compressed file. | |
gzputc returns the value that was written, or -1 in case of error. | |
*/ | |
/* | |
Reads one byte from the compressed file. gzgetc returns this byte | |
or -1 in case of end of file or error. | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
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. | |
*/ | |
/* | |
Rewinds the given file. This function is supported only for reading. | |
gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) | |
*/ | |
/* | |
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) | |
*/ | |
/* | |
Returns 1 when EOF has previously been detected reading the given | |
input stream, otherwise zero. | |
*/ | |
/* | |
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). | |
*/ | |
/* | |
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) 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(); | |
*/ | |
/* | |
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) 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)) | |
#ifdef __cplusplus | |
} | |
#endif | |
#endif /* _ZLIB_H */ |