zlib.h

经典的ppp程序

/*	$Id: zlib.h,v 1.1 1999/03/23 03:21:58 paulus Exp $	*/

/*
 * This file is derived from zlib.h and zconf.h from the zlib-0.95
 * distribution by Jean-loup Gailly and Mark Adler, with some additions
 * by Paul Mackerras to aid in implementing Deflate compression and
 * decompression for PPP packets.
 */

/* zlib.h -- interface of the 'zlib' general purpose compression library
  version 0.95, Aug 16th, 1995.

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

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.

  Jean-loup Gailly        Mark Adler
  [e-mail]    [e-mail]
 */

#ifndef _ZLIB_H
#define _ZLIB_H

/* #include "zconf.h" */	/* included directly here */

/* zconf.h -- configuration of the zlib compression library
 * Copyright (C) 1995 Jean-loup Gailly.
 * For conditions of distribution and use, see copyright notice in zlib.h 
 */

/* From: zconf.h,v 1.12 1995/05/03 17:27:12 jloup Exp */

/*
     The library does not install any signal handler. It is recommended to
  add at least a handler for SIGSEGV when decompressing; the library checks
  the consistency of the input data whenever possible but may go nuts
  for some forms of corrupted input.
 */

/*
 * Compile with -DMAXSEG_64K if the alloc function cannot allocate more
 * than 64k bytes at a time (needed on systems with 16-bit int).
 * Compile with -DUNALIGNED_OK if it is OK to access shorts or ints
 * at addresses which are not a multiple of their size.
 * Under DOS, -DFAR=far or -DFAR=__far may be needed.
 */

#ifndef STDC
#  if defined(MSDOS) || defined(__STDC__) || defined(__cplusplus)
#    define STDC
#  endif
#endif

#ifdef	__MWERKS__ /* Metrowerks CodeWarrior declares fileno() in unix.h */
#  include <unix.h>
#endif

/* Maximum value for memLevel in deflateInit2 */
#ifndef MAX_MEM_LEVEL
#  ifdef MAXSEG_64K
#    define MAX_MEM_LEVEL 8
#  else
#    define MAX_MEM_LEVEL 9
#  endif
#endif

#ifndef FAR
#  define FAR
#endif

/* Maximum value for windowBits in deflateInit2 and inflateInit2 */
#ifndef MAX_WBITS
#  define MAX_WBITS   15 /* 32K LZ77 window */
#endif

/* The memory requirements for deflate are (in bytes):
            1 << (windowBits+2)   +  1 << (memLevel+9)
 that is: 128K for windowBits=15  +  128K for memLevel = 8  (default values)
 plus a few kilobytes for small objects. For example, if you want to reduce
 the default memory requirements from 256K to 128K, compile with
     make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7"
 Of course this will generally degrade compression (there's no free lunch).

   The memory requirements for inflate are (in bytes) 1 << windowBits
 that is, 32K for windowBits=15 (default value) plus a few kilobytes
 for small objects.
*/

                        /* Type declarations */

#ifndef OF /* function prototypes */
#  ifdef STDC
#    define OF(args)  args
#  else
#    define OF(args)  ()
#  endif
#endif

typedef unsigned char  Byte;  /* 8 bits */
typedef unsigned int   uInt;  /* 16 bits or more */
typedef unsigned long  uLong; /* 32 bits or more */

typedef Byte FAR Bytef;
typedef char FAR charf;
typedef int FAR intf;
typedef uInt FAR uIntf;
typedef uLong FAR uLongf;

#ifdef STDC
   typedef void FAR *voidpf;
   typedef void     *voidp;
#else
   typedef Byte FAR *voidpf;
   typedef Byte     *voidp;
#endif

/* end of original zconf.h */

#define ZLIB_VERSION "0.95P"

/* 
     The 'zlib' compression library provides in-memory compression and
  decompression functions, including integrity checks of the uncompressed
  data.  This version of the library supports only one compression method
  (deflation) but other algorithms may be added later and will have the same
  stream interface.

     For compression the application must provide the output buffer and
  may optionally provide the input buffer for optimization. For decompression,
  the application must provide the input buffer and may optionally provide
  the output buffer for optimization.

     Compression can be done in a single step if the buffers are large
  enough (for example if an input file is mmap'ed), or can be done by
  repeated calls of the compression function.  In the latter case, the
  application must provide more input and/or consume the output
  (providing more output space) before each call.
*/

typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
typedef void   (*free_func)  OF((voidpf opaque, voidpf address, uInt nbytes));

struct internal_state;

typedef struct z_stream_s {
    Bytef    *next_in;  /* next input byte */
    uInt     avail_in;  /* number of bytes available at next_in */
    uLong    total_in;  /* total nb of input bytes read so far */

    Bytef    *next_out; /* next output byte should be put there */
    uInt     avail_out; /* remaining free space at next_out */
    uLong    total_out; /* total nb of bytes output so far */

    char     *msg;      /* last error message, NULL if no error */
    struct internal_state FAR *state; /* not visible by applications */

    alloc_func zalloc;  /* used to allocate the internal state */
    free_func  zfree;   /* used to free the internal state */
    voidp      opaque;  /* private data object passed to zalloc and zfree */

    Byte     data_type; /* best guess about the data type: ascii or binary */

} z_stream;

/*
   The application must update next_in and avail_in when avail_in has
   dropped to zero. It must update next_out and avail_out when avail_out
   has dropped to zero. The application must initialize zalloc, zfree and
   opaque before calling the init function. All other fields are set by the
   compression library and must not be updated by the application.

   The opaque value provided by the application will be passed as the first
   parameter for calls of zalloc and zfree. This can be useful for custom
   memory management. The compression library attaches no meaning to the
   opaque value.

   zalloc must return Z_NULL if there is not enough memory for the object.
   On 16-bit systems, the functions zalloc and zfree must be able to allocate
   exactly 65536 bytes, but will not be required to allocate more than this
   if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
   pointers returned by zalloc for objects of exactly 65536 bytes *must*
   have their offset normalized to zero. The default allocation function
   provided by this library ensures this (see zutil.c). To reduce memory
   requirements and avoid any allocation of 64K objects, at the expense of
   compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).

   The fields total_in and total_out can be used for statistics or
   progress reports. After compression, total_in holds the total size of
   the uncompressed data and may be saved for use in the decompressor
   (particularly if the decompressor wants to decompress everything in
   a single step).
*/

                        /* constants */

#define Z_NO_FLUSH      0
#define Z_PARTIAL_FLUSH 1
#define Z_FULL_FLUSH    2
#define Z_SYNC_FLUSH    3 /* experimental: partial_flush + byte align */
#define Z_FINISH        4
#define Z_PACKET_FLUSH	5
/* See deflate() below for the usage of these constants */

#define Z_OK            0
#define Z_STREAM_END    1
#define Z_ERRNO        (-1)
#define Z_STREAM_ERROR (-2)
#define Z_DATA_ERROR   (-3)
#define Z_MEM_ERROR    (-4)
#define Z_BUF_ERROR    (-5)
/* error codes for the compression/decompression functions */

#define Z_BEST_SPEED             1
#define Z_BEST_COMPRESSION       9
#define Z_DEFAULT_COMPRESSION  (-1)
/* compression levels */

#define Z_FILTERED            1
#define Z_HUFFMAN_ONLY        2
#define Z_DEFAULT_STRATEGY    0

#define Z_BINARY   0
#define Z_ASCII    1
#define Z_UNKNOWN  2
/* Used to set the data_type field */

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

extern char *zlib_version;
/* The application can compare zlib_version and ZLIB_VERSION for consistency.
   If the first character differs, the library code actually used is
   not compatible with the zlib.h header file used by the application.
 */

                        /* basic functions */

extern int deflateInit OF((z_stream *strm, int level));
/* 
     Initializes the internal stream state for compression. The fields
   zalloc, zfree and opaque must be initialized before by the caller.
   If zalloc and zfree are set to Z_NULL, deflateInit updates them to
   use default allocation functions.

     The compression level must be Z_DEFAULT_COMPRESSION, or between 1 and 9:
   1 gives best speed, 9 gives best compression. Z_DEFAULT_COMPRESSION requests
   a default compromise between speed and compression (currently equivalent
   to level 6).

     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
   enough memory, Z_STREAM_ERROR if level is not a valid compression level.
   msg is set to null if there is no error message.  deflateInit does not
   perform any compression: this will be done by deflate().
*/


extern int deflate OF((z_stream *strm, int flush));
/*
  Performs one or both of the following actions:

  - Compress more input starting at next_in and update next_in and avail_in
    accordingly. If not all input can be processed (because there is not
    enough room in the output buffer), next_in and avail_in are updated and
    processing will resume at this point for the next call of deflate().

  - Provide more output starting at next_out and update next_out and avail_out
    accordingly. This action is forced if the parameter flush is non zero.
    Forcing flush frequently degrades the compression ratio, so this parameter
    should be set only when necessary (in interactive applications).
    Some output may be provided even if flush is not set.

  Before the call of deflate(), the application should ensure that at least
  one of the actions is possible, by providing more input and/or consuming
  more output, and updating avail_in or avail_out accordingly; avail_out
  should never be zero before the call. The application can consume the
  compressed output when it wants, for example when the output buffer is full
  (avail_out == 0), or after each call of deflate().

    If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression
  block is terminated and flushed to the output buffer so that the
  decompressor can get all input data available so far. For method 9, a future
  variant on method 8, the current block will be flushed but not terminated.
  If flush is set to Z_FULL_FLUSH, the compression block is terminated, a
  special marker is output and the compression dictionary is discarded; this
  is useful to allow the decompressor to synchronize if one compressed block
  has been damaged (see inflateSync below).  Flushing degrades compression and
  so should be used only when necessary.  Using Z_FULL_FLUSH too often can
  seriously degrade the compression. If deflate returns with avail_out == 0,
  this function must be called again with the same value of the flush
  parameter and more output space (updated avail_out), until the flush is
  complete (deflate returns with non-zero avail_out).

    If the parameter flush is set to Z_PACKET_FLUSH, the compression
  block is terminated, and a zero-length stored block is output,
  omitting the length bytes (the effect of this is that the 3-bit type
  code 000 for a stored block is output, and the output is then
  byte-aligned).  This is designed for use at the end of a PPP packet.
  In addition, if the current compression block contains all the data
  since the last Z_PACKET_FLUSH, it is never output as a stored block.
  If the current compression block output as a static or dynamic block
  would not be at least `minCompression' bytes smaller than the
  original data, then nothing is output for that block.  (The type
  code for the zero-length stored block is still output, resulting in