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/* $Id: zlib.h,v 1.1 1999/03/23 03:21:58 paulus Exp $ */
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* This file is derived from zlib.h and zconf.h from the zlib-0.95
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* distribution by Jean-loup Gailly and Mark Adler, with some additions
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* by Paul Mackerras to aid in implementing Deflate compression and
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* decompression for PPP packets.
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/* zlib.h -- interface of the 'zlib' general purpose compression library
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version 0.95, Aug 16th, 1995.
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Copyright (C) 1995 Jean-loup Gailly and Mark Adler
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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Jean-loup Gailly Mark Adler
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gzip@prep.ai.mit.edu madler@alumni.caltech.edu
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/* #include "zconf.h" */ /* included directly here */
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/* zconf.h -- configuration of the zlib compression library
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* Copyright (C) 1995 Jean-loup Gailly.
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* For conditions of distribution and use, see copyright notice in zlib.h
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/* From: zconf.h,v 1.12 1995/05/03 17:27:12 jloup Exp */
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The library does not install any signal handler. It is recommended to
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add at least a handler for SIGSEGV when decompressing; the library checks
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the consistency of the input data whenever possible but may go nuts
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for some forms of corrupted input.
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* Compile with -DMAXSEG_64K if the alloc function cannot allocate more
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* than 64k bytes at a time (needed on systems with 16-bit int).
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* Compile with -DUNALIGNED_OK if it is OK to access shorts or ints
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* at addresses which are not a multiple of their size.
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* Under DOS, -DFAR=far or -DFAR=__far may be needed.
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# if defined(MSDOS) || defined(__STDC__) || defined(__cplusplus)
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#ifdef __MWERKS__ /* Metrowerks CodeWarrior declares fileno() in unix.h */
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/* Maximum value for memLevel in deflateInit2 */
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# define MAX_MEM_LEVEL 8
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# define MAX_MEM_LEVEL 9
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/* Maximum value for windowBits in deflateInit2 and inflateInit2 */
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# define MAX_WBITS 15 /* 32K LZ77 window */
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/* The memory requirements for deflate are (in bytes):
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1 << (windowBits+2) + 1 << (memLevel+9)
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that is: 128K for windowBits=15 + 128K for memLevel = 8 (default values)
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plus a few kilobytes for small objects. For example, if you want to reduce
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the default memory requirements from 256K to 128K, compile with
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make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
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Of course this will generally degrade compression (there's no free lunch).
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The memory requirements for inflate are (in bytes) 1 << windowBits
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that is, 32K for windowBits=15 (default value) plus a few kilobytes
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/* Type declarations */
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#ifndef OF /* function prototypes */
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# define OF(args) args
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typedef unsigned char Byte; /* 8 bits */
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typedef unsigned int uInt; /* 16 bits or more */
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typedef unsigned long uLong; /* 32 bits or more */
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typedef Byte FAR Bytef;
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typedef char FAR charf;
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typedef int FAR intf;
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typedef uInt FAR uIntf;
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typedef uLong FAR uLongf;
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typedef void FAR *voidpf;
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typedef Byte FAR *voidpf;
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/* end of original zconf.h */
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#define ZLIB_VERSION "0.95P"
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The 'zlib' compression library provides in-memory compression and
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decompression functions, including integrity checks of the uncompressed
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data. This version of the library supports only one compression method
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(deflation) but other algorithms may be added later and will have the same
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For compression the application must provide the output buffer and
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may optionally provide the input buffer for optimization. For decompression,
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the application must provide the input buffer and may optionally provide
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the output buffer for optimization.
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Compression can be done in a single step if the buffers are large
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enough (for example if an input file is mmap'ed), or can be done by
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repeated calls of the compression function. In the latter case, the
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application must provide more input and/or consume the output
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(providing more output space) before each call.
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typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
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typedef void (*free_func) OF((voidpf opaque, voidpf address, uInt nbytes));
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struct internal_state;
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typedef struct z_stream_s {
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Bytef *next_in; /* next input byte */
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uInt avail_in; /* number of bytes available at next_in */
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uLong total_in; /* total nb of input bytes read so far */
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Bytef *next_out; /* next output byte should be put there */
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uInt avail_out; /* remaining free space at next_out */
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uLong total_out; /* total nb of bytes output so far */
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char *msg; /* last error message, NULL if no error */
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struct internal_state FAR *state; /* not visible by applications */
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alloc_func zalloc; /* used to allocate the internal state */
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free_func zfree; /* used to free the internal state */
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voidp opaque; /* private data object passed to zalloc and zfree */
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Byte data_type; /* best guess about the data type: ascii or binary */
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The application must update next_in and avail_in when avail_in has
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dropped to zero. It must update next_out and avail_out when avail_out
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has dropped to zero. The application must initialize zalloc, zfree and
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opaque before calling the init function. All other fields are set by the
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compression library and must not be updated by the application.
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The opaque value provided by the application will be passed as the first
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parameter for calls of zalloc and zfree. This can be useful for custom
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memory management. The compression library attaches no meaning to the
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zalloc must return Z_NULL if there is not enough memory for the object.
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On 16-bit systems, the functions zalloc and zfree must be able to allocate
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exactly 65536 bytes, but will not be required to allocate more than this
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if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
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pointers returned by zalloc for objects of exactly 65536 bytes *must*
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have their offset normalized to zero. The default allocation function
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provided by this library ensures this (see zutil.c). To reduce memory
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requirements and avoid any allocation of 64K objects, at the expense of
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compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
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The fields total_in and total_out can be used for statistics or
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progress reports. After compression, total_in holds the total size of
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the uncompressed data and may be saved for use in the decompressor
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(particularly if the decompressor wants to decompress everything in
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#define Z_PARTIAL_FLUSH 1
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#define Z_FULL_FLUSH 2
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#define Z_SYNC_FLUSH 3 /* experimental: partial_flush + byte align */
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#define Z_PACKET_FLUSH 5
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/* See deflate() below for the usage of these constants */
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#define Z_STREAM_END 1
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#define Z_STREAM_ERROR (-2)
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#define Z_DATA_ERROR (-3)
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#define Z_MEM_ERROR (-4)
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#define Z_BUF_ERROR (-5)
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/* error codes for the compression/decompression functions */
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#define Z_BEST_SPEED 1
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#define Z_BEST_COMPRESSION 9
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#define Z_DEFAULT_COMPRESSION (-1)
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/* compression levels */
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#define Z_HUFFMAN_ONLY 2
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#define Z_DEFAULT_STRATEGY 0
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/* Used to set the data_type field */
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#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
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extern char *zlib_version;
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/* The application can compare zlib_version and ZLIB_VERSION for consistency.
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If the first character differs, the library code actually used is
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not compatible with the zlib.h header file used by the application.
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/* basic functions */
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extern int deflateInit OF((z_stream *strm, int level));
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Initializes the internal stream state for compression. The fields
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zalloc, zfree and opaque must be initialized before by the caller.
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If zalloc and zfree are set to Z_NULL, deflateInit updates them to
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use default allocation functions.
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The compression level must be Z_DEFAULT_COMPRESSION, or between 1 and 9:
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1 gives best speed, 9 gives best compression. Z_DEFAULT_COMPRESSION requests
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a default compromise between speed and compression (currently equivalent
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deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
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enough memory, Z_STREAM_ERROR if level is not a valid compression level.
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msg is set to null if there is no error message. deflateInit does not
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perform any compression: this will be done by deflate().
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extern int deflate OF((z_stream *strm, int flush));
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Performs one or both of the following actions:
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- Compress more input starting at next_in and update next_in and avail_in
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accordingly. If not all input can be processed (because there is not
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enough room in the output buffer), next_in and avail_in are updated and
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processing will resume at this point for the next call of deflate().
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- Provide more output starting at next_out and update next_out and avail_out
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accordingly. This action is forced if the parameter flush is non zero.
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Forcing flush frequently degrades the compression ratio, so this parameter
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should be set only when necessary (in interactive applications).
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Some output may be provided even if flush is not set.
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Before the call of deflate(), the application should ensure that at least
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one of the actions is possible, by providing more input and/or consuming
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more output, and updating avail_in or avail_out accordingly; avail_out
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should never be zero before the call. The application can consume the
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compressed output when it wants, for example when the output buffer is full
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(avail_out == 0), or after each call of deflate().
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If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression
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block is terminated and flushed to the output buffer so that the
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decompressor can get all input data available so far. For method 9, a future
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variant on method 8, the current block will be flushed but not terminated.
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If flush is set to Z_FULL_FLUSH, the compression block is terminated, a
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special marker is output and the compression dictionary is discarded; this
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is useful to allow the decompressor to synchronize if one compressed block
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has been damaged (see inflateSync below). Flushing degrades compression and
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so should be used only when necessary. Using Z_FULL_FLUSH too often can
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seriously degrade the compression. If deflate returns with avail_out == 0,
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this function must be called again with the same value of the flush
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parameter and more output space (updated avail_out), until the flush is
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complete (deflate returns with non-zero avail_out).
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If the parameter flush is set to Z_PACKET_FLUSH, the compression
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block is terminated, and a zero-length stored block is output,
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omitting the length bytes (the effect of this is that the 3-bit type
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code 000 for a stored block is output, and the output is then
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byte-aligned). This is designed for use at the end of a PPP packet.
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In addition, if the current compression block contains all the data
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since the last Z_PACKET_FLUSH, it is never output as a stored block.
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If the current compression block output as a static or dynamic block
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would not be at least `minCompression' bytes smaller than the
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original data, then nothing is output for that block. (The type
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code for the zero-length stored block is still output, resulting in
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a single zero byte being output for the whole packet.)
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`MinCompression' is a parameter to deflateInit2, or 0 if deflateInit
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If the parameter flush is set to Z_FINISH, all pending input is processed,
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all pending output is flushed and deflate returns with Z_STREAM_END if there
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was enough output space; if deflate returns with Z_OK, this function must be
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called again with Z_FINISH and more output space (updated avail_out) but no
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more input data, until it returns with Z_STREAM_END or an error. After
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deflate has returned Z_STREAM_END, the only possible operations on the
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stream are deflateReset or deflateEnd.
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Z_FINISH can be used immediately after deflateInit if all the compression
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is to be done in a single step. In this case, avail_out must be at least
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0.1% larger than avail_in plus 12 bytes. If deflate does not return
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Z_STREAM_END, then it must be called again as described above.
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deflate() may update data_type if it can make a good guess about
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the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
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binary. This field is only for information purposes and does not affect
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the compression algorithm in any manner.
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deflate() returns Z_OK if some progress has been made (more input
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processed or more output produced), Z_STREAM_END if all input has been
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consumed and all output has been produced (only when flush is set to
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Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
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if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible.
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extern int deflateEnd OF((z_stream *strm));
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All dynamically allocated data structures for this stream are freed.
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This function discards any unprocessed input and does not flush any
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deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
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stream state was inconsistent. In the error case, msg may be set
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but then points to a static string (which must not be deallocated).
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extern int inflateInit OF((z_stream *strm));
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Initializes the internal stream state for decompression. The fields
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zalloc and zfree must be initialized before by the caller. If zalloc and
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zfree are set to Z_NULL, inflateInit updates them to use default allocation
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inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
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enough memory. msg is set to null if there is no error message.
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inflateInit does not perform any decompression: this will be done by
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extern int inflate OF((z_stream *strm, int flush));
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Performs one or both of the following actions:
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- Decompress more input starting at next_in and update next_in and avail_in
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accordingly. If not all input can be processed (because there is not
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enough room in the output buffer), next_in is updated and processing
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will resume at this point for the next call of inflate().
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- Provide more output starting at next_out and update next_out and avail_out
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accordingly. inflate() always provides as much output as possible
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(until there is no more input data or no more space in the output buffer).
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Before the call of inflate(), the application should ensure that at least
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one of the actions is possible, by providing more input and/or consuming
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more output, and updating the next_* and avail_* values accordingly.
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The application can consume the uncompressed output when it wants, for
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example when the output buffer is full (avail_out == 0), or after each
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If the parameter flush is set to Z_PARTIAL_FLUSH or Z_PACKET_FLUSH,
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inflate flushes as much output as possible to the output buffer. The
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flushing behavior of inflate is not specified for values of the flush
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parameter other than Z_PARTIAL_FLUSH, Z_PACKET_FLUSH or Z_FINISH, but the
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current implementation actually flushes as much output as possible
398
anyway. For Z_PACKET_FLUSH, inflate checks that once all the input data
399
has been consumed, it is expecting to see the length field of a stored
400
block; if not, it returns Z_DATA_ERROR.
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inflate() should normally be called until it returns Z_STREAM_END or an
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error. However if all decompression is to be performed in a single step
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(a single call of inflate), the parameter flush should be set to
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Z_FINISH. In this case all pending input is processed and all pending
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output is flushed; avail_out must be large enough to hold all the
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uncompressed data. (The size of the uncompressed data may have been saved
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by the compressor for this purpose.) The next operation on this stream must
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be inflateEnd to deallocate the decompression state. The use of Z_FINISH
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is never required, but can be used to inform inflate that a faster routine
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may be used for the single inflate() call.
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inflate() returns Z_OK if some progress has been made (more input
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processed or more output produced), Z_STREAM_END if the end of the
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compressed data has been reached and all uncompressed output has been
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produced, Z_DATA_ERROR if the input data was corrupted, Z_STREAM_ERROR if
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the stream structure was inconsistent (for example if next_in or next_out
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was NULL), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if no
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progress is possible or if there was not enough room in the output buffer
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when Z_FINISH is used. In the Z_DATA_ERROR case, the application may then
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call inflateSync to look for a good compression block. */
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extern int inflateEnd OF((z_stream *strm));
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All dynamically allocated data structures for this stream are freed.
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This function discards any unprocessed input and does not flush any
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inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
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was inconsistent. In the error case, msg may be set but then points to a
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static string (which must not be deallocated).
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/* advanced functions */
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The following functions are needed only in some special applications.
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extern int deflateInit2 OF((z_stream *strm,
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int minCompression));
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This is another version of deflateInit with more compression options. The
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fields next_in, zalloc and zfree must be initialized before by the caller.
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The method parameter is the compression method. It must be 8 in this
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version of the library. (Method 9 will allow a 64K history buffer and
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partial block flushes.)
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The windowBits parameter is the base two logarithm of the window size
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(the size of the history buffer). It should be in the range 8..15 for this
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version of the library (the value 16 will be allowed for method 9). Larger
459
values of this parameter result in better compression at the expense of
460
memory usage. The default value is 15 if deflateInit is used instead.
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The memLevel parameter specifies how much memory should be allocated
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for the internal compression state. memLevel=1 uses minimum memory but
464
is slow and reduces compression ratio; memLevel=9 uses maximum memory
465
for optimal speed. The default value is 8. See zconf.h for total memory
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usage as a function of windowBits and memLevel.
468
The strategy parameter is used to tune the compression algorithm. Use
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the value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data
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produced by a filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman
471
encoding only (no string match). Filtered data consists mostly of small
472
values with a somewhat random distribution. In this case, the
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compression algorithm is tuned to compress them better. The strategy
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parameter only affects the compression ratio but not the correctness of
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the compressed output even if it is not set appropriately.
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The minCompression parameter specifies the minimum reduction in size
478
required for a compressed block to be output when Z_PACKET_FLUSH is
479
used (see the description of deflate above).
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If next_in is not null, the library will use this buffer to hold also
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some history information; the buffer must either hold the entire input
483
data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in
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is null, the library will allocate its own history buffer (and leave next_in
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null). next_out need not be provided here but must be provided by the
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application for the next call of deflate().
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If the history buffer is provided by the application, next_in must
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must never be changed by the application since the compressor maintains
490
information inside this buffer from call to call; the application
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must provide more input only by increasing avail_in. next_in is always
492
reset by the library in this case.
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deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
495
not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
496
an invalid method). msg is set to null if there is no error message.
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deflateInit2 does not perform any compression: this will be done by
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extern int deflateCopy OF((z_stream *dest,
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Sets the destination stream as a complete copy of the source stream. If
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the source stream is using an application-supplied history buffer, a new
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buffer is allocated for the destination stream. The compressed output
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buffer is always application-supplied. It's the responsibility of the
508
application to provide the correct values of next_out and avail_out for the
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next call of deflate.
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This function is useful when several compression strategies will be
512
tried, for example when there are several ways of pre-processing the input
513
data with a filter. The streams that will be discarded should then be freed
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by calling deflateEnd. Note that deflateCopy duplicates the internal
515
compression state which can be quite large, so this strategy is slow and
516
can consume lots of memory.
518
deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
519
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
520
(such as zalloc being NULL). msg is left unchanged in both source and
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extern int deflateReset OF((z_stream *strm));
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This function is equivalent to deflateEnd followed by deflateInit,
527
but does not free and reallocate all the internal compression state.
528
The stream will keep the same compression level and any other attributes
529
that may have been set by deflateInit2.
531
deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
532
stream state was inconsistent (such as zalloc or state being NULL).
535
extern int inflateInit2 OF((z_stream *strm,
538
This is another version of inflateInit with more compression options. The
539
fields next_out, zalloc and zfree must be initialized before by the caller.
541
The windowBits parameter is the base two logarithm of the maximum window
542
size (the size of the history buffer). It should be in the range 8..15 for
543
this version of the library (the value 16 will be allowed soon). The
544
default value is 15 if inflateInit is used instead. If a compressed stream
545
with a larger window size is given as input, inflate() will return with
546
the error code Z_DATA_ERROR instead of trying to allocate a larger window.
548
If next_out is not null, the library will use this buffer for the history
549
buffer; the buffer must either be large enough to hold the entire output
550
data, or have at least 1<<windowBits bytes. If next_out is null, the
551
library will allocate its own buffer (and leave next_out null). next_in
552
need not be provided here but must be provided by the application for the
553
next call of inflate().
555
If the history buffer is provided by the application, next_out must
556
never be changed by the application since the decompressor maintains
557
history information inside this buffer from call to call; the application
558
can only reset next_out to the beginning of the history buffer when
559
avail_out is zero and all output has been consumed.
561
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
562
not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
563
windowBits < 8). msg is set to null if there is no error message.
564
inflateInit2 does not perform any decompression: this will be done by
568
extern int inflateSync OF((z_stream *strm));
570
Skips invalid compressed data until the special marker (see deflate()
571
above) can be found, or until all available input is skipped. No output
574
inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR
575
if no more input was provided, Z_DATA_ERROR if no marker has been found,
576
or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
577
case, the application may save the current current value of total_in which
578
indicates where valid compressed data was found. In the error case, the
579
application may repeatedly call inflateSync, providing more input each time,
580
until success or end of the input data.
583
extern int inflateReset OF((z_stream *strm));
585
This function is equivalent to inflateEnd followed by inflateInit,
586
but does not free and reallocate all the internal decompression state.
587
The stream will keep attributes that may have been set by inflateInit2.
589
inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
590
stream state was inconsistent (such as zalloc or state being NULL).
593
extern int inflateIncomp OF((z_stream *strm));
595
This function adds the data at next_in (avail_in bytes) to the output
596
history without performing any output. There must be no pending output,
597
and the decompressor must be expecting to see the start of a block.
598
Calling this function is equivalent to decompressing a stored block
599
containing the data at next_in (except that the data is not output).
602
/* checksum functions */
605
This function is not related to compression but is exported
606
anyway because it might be useful in applications using the
610
extern uLong adler32 OF((uLong adler, Bytef *buf, uInt len));
613
Update a running Adler-32 checksum with the bytes buf[0..len-1] and
614
return the updated checksum. If buf is NULL, this function returns
615
the required initial value for the checksum.
616
An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
617
much faster. Usage example:
619
uLong adler = adler32(0L, Z_NULL, 0);
621
while (read_buffer(buffer, length) != EOF) {
622
adler = adler32(adler, buffer, length);
624
if (adler != original_adler) error();
628
struct internal_state {int dummy;}; /* hack for buggy compilers */
added
removed
pppdump/zlib.h
