/* zlib.h -- interface of the 'zlib' general purpose compression library

version 1.2.2, October 3rd, 2004

Copyright (C) 1995-2004 Jean-loup Gailly and Mark Adler

This software is provided 'as-is', without any express or implied

warranty. In no event will the authors be held liable for any damages

arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,

including commercial applications, and to alter it and redistribute it

freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not

claim that you wrote the original software. If you use this software

in a product, an acknowledgment in the product documentation would be

appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be

misrepresented as being the original software.

3. This notice may not be removed or altered from any source distribution.

Jean-loup Gailly Mark Adler

jloup@gzip.org madler@alumni.caltech.edu

The data format used by the zlib library is described by RFCs (Request for

Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt

(zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).

*/

#ifndef ZLIB_H

#define ZLIB_H

#include "zconf.h"

#ifdef __cplusplus

extern "C" {

#endif

#define ZLIB_VERSION "1.2.2"

#define ZLIB_VERNUM 0x1220

/*

The 'zlib' compression library provides in-memory compression and

decompression functions, including integrity checks of the uncompressed

data. This version of the library supports only one compression method

(deflation) but other algorithms will be added later and will have the same

stream interface.

Compression can be done in a single step if the buffers are large

enough (for example if an input file is mmap'ed), or can be done by

repeated calls of the compression function. In the latter case, the

application must provide more input and/or consume the output

(providing more output space) before each call.

The compressed data format used by default by the in-memory functions is

the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped

around a deflate stream, which is itself documented in RFC 1951.

The library also supports reading and writing files in gzip (.gz) format

with an interface similar to that of stdio using the functions that start

with "gz". The gzip format is different from the zlib format. gzip is a

gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.

This library can optionally read and write gzip streams in memory as well.

The zlib format was designed to be compact and fast for use in memory

and on communications channels. The gzip format was designed for single-

file compression on file systems, has a larger header than zlib to maintain

directory information, and uses a different, slower check method than zlib.

The library does not install any signal handler. The decoder checks

the consistency of the compressed data, so the library should never

crash even in case of corrupted input.

*/

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 {

} 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

#define Z_BLOCK 5

/* Allowed flush values; see deflate() and inflate() below for details */

#define Z_OK 0

#define Z_STREAM_END 1

#define Z_NEED_DICT 2

#define Z_ERRNO (-1)

#define Z_STREAM_ERROR (-2)

#define Z_DATA_ERROR (-3)

#define Z_MEM_ERROR (-4)

#define Z_BUF_ERROR (-5)

#define Z_VERSION_ERROR (-6)

/* Return codes for the compression/decompression functions. Negative

* values are errors, positive values are used for special but normal events.

*/

#define Z_NO_COMPRESSION 0

#define Z_BEST_SPEED 1

#define Z_BEST_COMPRESSION 9

#define Z_DEFAULT_COMPRESSION (-1)

/* compression levels */

#define Z_FILTERED 1

#define Z_HUFFMAN_ONLY 2

#define Z_RLE 3

#define Z_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 (though see inflate()) */

#define Z_DEFLATED 8

/* The deflate compression method (the only one supported in this version) */

#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */

#define zlib_version zlibVersion()

/* for compatibility with versions < 1.0.2 */

/* 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). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that

avail_out is greater than six to avoid repeated flush markers due to

avail_out == 0 on return.

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

the value returned by deflateBound (see below). 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). Note that Z_BUF_ERROR is not

fatal, and deflate() can be called again with more input and more output

space to continue compressing.

*/

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 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.

The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,

Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much

output as possible to the output buffer. Z_BLOCK requests that inflate() stop

if and when it get to the next deflate block boundary. When decoding the zlib

or gzip format, this will cause inflate() to return immediately after the

header and before the first block. When doing a raw inflate, inflate() will

go ahead and process the first block, and will return when it gets to the end

of that block, or when it runs out of data.

The Z_BLOCK option assists in appending to or combining deflate streams.

Also to assist in this, on return inflate() will set strm->data_type to the

number of unused bits in the last byte taken from strm->next_in, plus 64

if inflate() is currently decoding the last block in the deflate stream,

plus 128 if inflate() returned immediately after decoding an end-of-block

code or decoding the complete header up to just before the first byte of the

deflate stream. The end-of-block will not be indicated until all of the

uncompressed data from that block has been written to strm->next_out. The

number of unused bits may in general be greater than seven, except when

bit 7 of data_type is set, in which case the number of unused bits will be

less than eight.

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 approach

may be used for the single inflate() call.

In this implementation, inflate() always flushes as much output as

possible to the output buffer, and always uses the faster approach on the

first call. So the only effect of the flush parameter in this implementation

is on the return value of inflate(), as noted below, or when it returns early

because Z_BLOCK is used.

If a preset dictionary is needed after this call (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() will decompress and check either zlib-wrapped or gzip-wrapped

deflate data. The header type is detected automatically. Any information

contained in the gzip header is not retained, so applications that need that

information should instead use raw inflate, see inflateInit2() below, or

inflateBack() and perform their own processing of the gzip header and

trailer.

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 check

value), 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. Note that Z_BUF_ERROR is not fatal, and

inflate() can be called again with more input and more output space to

continue decompressing. If Z_DATA_ERROR is returned, the application may then

call inflateSync() to look for a good compression block if a partial recovery

of the data is desired.

*/

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.

windowBits can also be -8..-15 for raw deflate. In this case, -windowBits

determines the window size. deflate() will then generate raw deflate data

with no zlib header or trailer, and will not compute an adler32 check value.

windowBits can also be greater than 15 for optional gzip encoding. Add

16 to windowBits to write a simple gzip header and trailer around the

compressed data instead of a zlib wrapper. The gzip header will have no

file name, no extra data, no comment, no modification time (set to zero),

no header crc, and the operating system will be set to 255 (unknown). If a

gzip stream is being written, strm->adler is a crc32 instead of an adler32.

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), Z_HUFFMAN_ONLY to force Huffman encoding only (no

string match), or Z_RLE to limit match distances to one (run-length

encoding). 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. Z_RLE is designed to be almost as fast as

Z_HUFFMAN_ONLY, but give better compression for PNG image data. 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.) If a raw deflate was requested, then the

adler32 value is not computed and strm->adler is not set.

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 uLong ZEXPORT deflateBound OF((z_streamp strm,

uLong sourceLen));

/*

deflateBound() returns an upper bound on the compressed size after

deflation of sourceLen bytes. It must be called after deflateInit()

or deflateInit2(). This would be used to allocate an output buffer

for deflation in a single pass, and so would be called before deflate().

*/

ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,

int bits,

int value));

/*

deflatePrime() inserts bits in the deflate output stream. The intent

is that this function is used to start off the deflate output with the

bits leftover from a previous deflate stream when appending to it. As such,

this function can only be used for raw deflate, and must be used before the

first deflate() call after a deflateInit2() or deflateReset(). bits must be

less than or equal to 16, and that many of the least significant bits of

value will be inserted in the output.

deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source

stream state was inconsistent.

*/

/*

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. windowBits must be greater than or equal to the windowBits value

provided to deflateInit2() while compressing, or it must be equal to 15 if

deflateInit2() was not used. 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.

windowBits can also be -8..-15 for raw inflate. In this case, -windowBits

determines the window size. inflate() will then process raw deflate data,

not looking for a zlib or gzip header, not generating a check value, and not

looking for any check values for comparison at the end of the stream. This

is for use with other formats that use the deflate compressed data format

such as zip. Those formats provide their own check values. If a custom

format is developed using the raw deflate format for compressed data, it is

recommended that a check value such as an adler32 or a crc32 be applied to

the uncompressed data as is done in the zlib, gzip, and zip formats. For

most applications, the zlib format should be used as is. Note that comments

above on the use in deflateInit2() applies to the magnitude of windowBits.

windowBits can also be greater than 15 for optional gzip decoding. Add

32 to windowBits to enable zlib and gzip decoding with automatic header

detection, or add 16 to decode only the gzip format (the zlib format will

return a Z_DATA_ERROR. If a gzip stream is being decoded, strm->adler is

a crc32 instead of an adler32.

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 inflateCopy 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 randomly accessing a large stream. The

first pass through the stream can periodically record the inflate state,

allowing restarting inflate at those points when randomly accessing the

stream.

inflateCopy 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 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).

*/

/*

ZEXTERN int ZEXPORT inflateBackInit OF((z_stream FAR *strm, int windowBits,

unsigned char FAR *window));

Initialize the internal stream state for decompression using inflateBack()

calls. The fields zalloc, zfree and opaque in strm must be initialized

before the call. If zalloc and zfree are Z_NULL, then the default library-

derived memory allocation routines are used. windowBits is the base two

logarithm of the window size, in the range 8..15. window is a caller

supplied buffer of that size. Except for special applications where it is

assured that deflate was used with small window sizes, windowBits must be 15

and a 32K byte window must be supplied to be able to decompress general

deflate streams.

See inflateBack() for the usage of these routines.

inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of

the paramaters are invalid, Z_MEM_ERROR if the internal state could not

be allocated, or Z_VERSION_ERROR if the version of the library does not

match the version of the header file.

*/

typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));

typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));

ZEXTERN int ZEXPORT inflateBack OF((z_stream FAR *strm,

in_func in, void FAR *in_desc,

out_func out, void FAR *out_desc));

/*

inflateBack() does a raw inflate with a single call using a call-back

interface for input and output. This is more efficient than inflate() for

file i/o applications in that it avoids copying between the output and the

sliding window by simply making the window itself the output buffer. This

function trusts the application to not change the output buffer passed by

the output function, at least until inflateBack() returns.

inflateBackInit() must be called first to allocate the internal state

and to initialize the state with the user-provided window buffer.

inflateBack() may then be used multiple times to inflate a complete, raw

deflate stream with each call. inflateBackEnd() is then called to free

the allocated state.

A raw deflate stream is one with no zlib or gzip header or trailer.

This routine would normally be used in a utility that reads zip or gzip

files and writes out uncompressed files. The utility would decode the

header and process the trailer on its own, hence this routine expects

only the raw deflate stream to decompress. This is different from the

normal behavior of inflate(), which expects either a zlib or gzip header and

trailer around the deflate stream.

inflateBack() uses two subroutines supplied by the caller that are then

called by inflateBack() for input and output. inflateBack() calls those

routines until it reads a complete deflate stream and writes out all of the

uncompressed data, or until it encounters an error. The function's

parameters and return types are defined above in the in_func and out_func

typedefs. inflateBack() will call in(in_desc, &buf) which should return the

number of bytes of provided input, and a pointer to that input in buf. If

there is no input available, in() must return zero--buf is ignored in that

case--and inflateBack() will return a buffer error. inflateBack() will call

out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()

should return zero on success, or non-zero on failure. If out() returns

non-zero, inflateBack() will return with an error. Neither in() nor out()

are permitted to change the contents of the window provided to

inflateBackInit(), which is also the buffer that out() uses to write from.

The length written by out() will be at most the window size. Any non-zero

amount of input may be provided by in().

For convenience, inflateBack() can be provided input on the first call by

setting strm->next_in and strm->avail_in. If that input is exhausted, then

in() will be called. Therefore strm->next_in must be initialized before

calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called

immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in

must also be initialized, and then if strm->avail_in is not zero, input will

initially be taken from strm->next_in[0 .. strm->avail_in - 1].

The in_desc and out_desc parameters of inflateBack() is passed as the

first parameter of in() and out() respectively when they are called. These

descriptors can be optionally used to pass any information that the caller-

supplied in() and out() functions need to do their job.

On return, inflateBack() will set strm->next_in and strm->avail_in to

pass back any unused input that was provided by the last in() call. The

return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR

if in() or out() returned an error, Z_DATA_ERROR if there was a format

error in the deflate stream (in which case strm->msg is set to indicate the

nature of the error), or Z_STREAM_ERROR if the stream was not properly

initialized. In the case of Z_BUF_ERROR, an input or output error can be

distinguished using strm->next_in which will be Z_NULL only if in() returned

an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to

out() returning non-zero. (in() will always be called before out(), so

strm->next_in is assured to be defined if out() returns non-zero.) Note

that inflateBack() cannot return Z_OK.

*/

ZEXTERN int ZEXPORT inflateBackEnd OF((z_stream FAR *strm));

/*

All memory allocated by inflateBackInit() is freed.

inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream

state was inconsistent.

*/

ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));

/* Return flags indicating compile-time options.

Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:

1.0: size of uInt

3.2: size of uLong

5.4: size of voidpf (pointer)

7.6: size of z_off_t

Compiler, assembler, and debug options:

8: DEBUG

9: ASMV or ASMINF -- use ASM code

10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention

11: 0 (reserved)

One-time table building (smaller code, but not thread-safe if true):

12: BUILDFIXED -- build static block decoding tables when needed

13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed

14,15: 0 (reserved)

Library content (indicates missing functionality):

16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking

deflate code when not needed)

17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect

and decode gzip streams (to avoid linking crc code)

18-19: 0 (reserved)

Operation variations (changes in library functionality):

20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate

21: FASTEST -- deflate algorithm with only one, lowest compression level

22,23: 0 (reserved)

The sprintf variant used by gzprintf (zero is best):

24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format

25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!

26: 0 = returns value, 1 = void -- 1 means inferred string length returned

Remainder:

27-31: 0 (reserved)

*/

/* 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 the value returned

by compressBound(sourceLen). 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 the value returned by

compressBound(sourceLen). 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 uLong ZEXPORT compressBound OF((uLong sourceLen));

/*

compressBound() returns an upper bound on the compressed size after

compress() or compress2() on sourceLen bytes. It would be used before

a compress() or compress2() call to allocate the destination buffer.

*/

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 or incomplete.

*/

typedef voidp gzFile;

ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));

/*

Opens a gzip (.gz) file for reading or writing. The mode parameter

is as in fopen ("rb" or "wb") but can also include a compression level

("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for

Huffman only compression as in "wb1h", or 'R' for run-length encoding

as in "wb1R". (See the description of deflateInit2 for more information

about the strategy parameter.)

gzopen can be used to read a file which is not in gzip format; in this

case gzread will directly read from the file without decompression.

gzopen returns NULL if the file could not be opened or if there was

insufficient memory to allocate the (de)compression state; errno

can be checked to distinguish the two cases (if errno is zero, the

zlib error is Z_MEM_ERROR). */

ZEXTERN 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,

voidpc buf, unsigned len));

/*

Writes the given number of uncompressed bytes into the compressed file.

gzwrite returns the number of uncompressed bytes actually written

(0 in case of error).

*/

ZEXTERN int 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). The number of

uncompressed bytes written is limited to 4095. The caller should assure that

this limit is not exceeded. If it is exceeded, then gzprintf() will return

return an error (0) with nothing written. In this case, there may also be a

buffer overflow with unpredictable consequences, which is possible only if

zlib was compiled with the insecure functions sprintf() or vsprintf()

because the secure snprintf() or vsnprintf() functions were not available.

*/