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#define _LZRW3_H
/*
* $Source: /homes/cvs/ftape-stacked/ftape/compressor/lzrw3.h,v $
* $Revision: 1.1 $
* $Date: 1997/10/05 19:12:30 $
*
* include files for lzrw3. Only slighty modified from the original
* version. Assembles the three include files compress.h, port.h and
* fastcopy.h from the original lzrw3 package.
*
*/
#include <linux/types.h>
#include <linux/string.h>
/******************************************************************************/
/* */
/* COMPRESS.H */
/* */
/******************************************************************************/
/* */
/* Author : Ross Williams. */
/* Date : December 1989. */
/* */
/* This header file defines the interface to a set of functions called */
/* 'compress', each member of which implements a particular data compression */
/* algorithm. */
/* */
/* Normally in C programming, for each .H file, there is a corresponding .C */
/* file that implements the functions promised in the .H file. */
/* Here, there are many .C files corresponding to this header file. */
/* Each comforming implementation file contains a single function */
/* called 'compress' that implements a single data compression */
/* algorithm that conforms with the interface specified in this header file. */
/* Only one algorithm can be linked in at a time in this organization. */
/* */
/******************************************************************************/
/* */
/* DEFINITION OF FUNCTION COMPRESS */
/* =============================== */
/* */
/* Summary of Function Compress */
/* ---------------------------- */
/* The action that 'compress' takes depends on its first argument called */
/* 'action'. The function provides three actions: */
/* */
/* - Return information about the algorithm. */
/* - Compress a block of memory. */
/* - Decompress a block of memory. */
/* */
/* Parameters */
/* ---------- */
/* See the formal C definition later for a description of the parameters. */
/* */
/* Constants */
/* --------- */
/* COMPRESS_OVERRUN: The constant COMPRESS_OVERRUN defines by how many bytes */
/* an algorithm is allowed to expand a block during a compression operation. */
/* */
/* Although compression algorithms usually compress data, there will always */
/* be data that a given compressor will expand (this can be proven). */
/* Fortunately, the degree of expansion can be limited to a single bit, by */
/* copying over the input data if the data gets bigger during compression. */
/* To allow for this possibility, the first bit of a compressed */
/* representation can be used as a flag indicating whether the */
/* input data was copied over, or truly compressed. In practice, the first */
/* byte would be used to store this bit so as to maintain byte alignment. */
/* */
/* Unfortunately, in general, the only way to tell if an algorithm will */
/* expand a particular block of data is to run the algorithm on the data. */
/* If the algorithm does not continuously monitor how many output bytes it */
/* has written, it might write an output block far larger than the input */
/* block before realizing that it has done so. */
/* On the other hand, continuous checks on output length are inefficient. */
/* */
/* To cater for all these problems, this interface definition: */
/* > Allows a compression algorithm to return an output block that is up to */
/* COMPRESS_OVERRUN bytes longer than the input block. */
/* > Allows a compression algorithm to write up to COMPRESS_OVERRUN bytes */
/* more than the length of the input block to the memory of the output */
/* block regardless of the length of the output block eventually returned. */
/* This allows an algorithm to overrun the length of the input block in the */
/* output block by up to COMPRESS_OVERRUN bytes between expansion checks. */
/* */
/* The problem does not arise for decompression. */
/* */
/* Identity Action */
/* --------------- */
/* > action must be COMPRESS_ACTION_IDENTITY. */
/* > p_dst_len must point to a longword to receive a longword address. */
/* > The value of the other parameters does not matter. */
/* > After execution, the longword that p_dst_len points to will be a pointer */
/* to a structure of type compress_identity. */
/* Thus, for example, after the call, (*p_dst_len)->memory will return the */
/* number of bytes of working memory that the algorithm requires to run. */
/* > The values of the identity structure returned are fixed constant */
/* attributes of the algorithm and must not vary from call to call. */
/* */
/* Common Requirements for Compression and Decompression Actions */
/* ------------------------------------------------------------- */
/* > wrk_mem must point to an unused block of memory of a length specified in */
/* the algorithm's identity block. The identity block can be obtained by */
/* making a separate call to compress, specifying the identity action. */
/* > The INPUT BLOCK is defined to be Memory[src_addr,src_addr+src_len-1]. */
/* > dst_len will be used to denote *p_dst_len. */
/* > dst_len is not read by compress, only written. */
/* > The value of dst_len is defined only upon termination. */
/* > The OUTPUT BLOCK is defined to be Memory[dst_addr,dst_addr+dst_len-1]. */
/* */
/* Compression Action */
/* ------------------ */
/* > action must be COMPRESS_ACTION_COMPRESS. */
/* > src_len must be in the range [0,COMPRESS_MAX_ORG]. */
/* > The OUTPUT ZONE is defined to be */
/* Memory[dst_addr,dst_addr+src_len-1+COMPRESS_OVERRUN]. */
/* > The function can modify any part of the output zone regardless of the */
/* final length of the output block. */
/* > The input block and the output zone must not overlap. */
/* > dst_len will be in the range [0,src_len+COMPRESS_OVERRUN]. */
/* > dst_len will be in the range [0,COMPRESS_MAX_COM] (from prev fact). */
/* > The output block will consist of a representation of the input block. */
/* */
/* Decompression Action */
/* -------------------- */
/* > action must be COMPRESS_ACTION_DECOMPRESS. */
/* > The input block must be the result of an earlier compression operation. */
/* > If the previous fact is true, the following facts must also be true: */
/* > src_len will be in the range [0,COMPRESS_MAX_COM]. */
/* > dst_len will be in the range [0,COMPRESS_MAX_ORG]. */
/* > The input and output blocks must not overlap. */
/* > Only the output block is modified. */
/* > Upon termination, the output block will consist of the bytes contained */
/* in the input block passed to the earlier compression operation. */
/* */
/******************************************************************************/
/******************************************************************************/
/* */
/* PORT.H */
/* */
/******************************************************************************/
/* */
/* This module contains macro definitions and types that are likely to */
/* change between computers. */
/* */
/******************************************************************************/
#ifndef DONE_PORT /* Only do this if not previously done. */
#ifdef THINK_C
#define UBYTE unsigned char /* Unsigned byte */
#define UWORD unsigned int /* Unsigned word (2 bytes) */
#define ULONG unsigned long /* Unsigned word (4 bytes) */
#define BOOL unsigned char /* Boolean */
#define FOPEN_BINARY_READ "rb" /* Mode string for binary reading. */
#define FOPEN_BINARY_WRITE "wb" /* Mode string for binary writing. */
#define FOPEN_TEXT_APPEND "a" /* Mode string for text appending. */
#define REAL double /* USed for floating point stuff. */
#endif
#if defined(LINUX) || defined(linux)
#define UBYTE __u8 /* Unsigned byte */
#define UWORD __u16 /* Unsigned word (2 bytes) */
#define ULONG __u32 /* Unsigned word (4 bytes) */
#define LONG __s32 /* Signed word (4 bytes) */
#define BOOL is not used here /* Boolean */
#define FOPEN_BINARY_READ not used /* Mode string for binary reading. */
#define FOPEN_BINARY_WRITE not used /* Mode string for binary writing. */
#define FOPEN_TEXT_APPEND not used /* Mode string for text appending. */
#define REAL not used /* USed for floating point stuff. */
#ifndef TRUE
#define TRUE 1
#endif
#endif
#define DONE_PORT /* Don't do all this again. */
#define MALLOC_FAIL NULL /* Failure status from malloc() */
#define LOCAL static /* For non-exported routines. */
#define EXPORT /* Signals exported function. */
#define then /* Useful for aligning ifs. */
#endif
/******************************************************************************/
/* End of PORT.H */
/******************************************************************************/
#define COMPRESS_ACTION_IDENTITY 0
#define COMPRESS_ACTION_COMPRESS 1
#define COMPRESS_ACTION_DECOMPRESS 2
#define COMPRESS_OVERRUN 1024
#define COMPRESS_MAX_COM 0x70000000
#define COMPRESS_MAX_ORG (COMPRESS_MAX_COM-COMPRESS_OVERRUN)
#define COMPRESS_MAX_STRLEN 255
/* The following structure provides information about the algorithm. */
/* > The top bit of id must be zero. The remaining bits must be chosen by */
/* the author of the algorithm by tossing a coin 31 times. */
/* > The amount of memory requested by the algorithm is specified in bytes */
/* and must be in the range [0,0x70000000]. */
/* > All strings s must be such that strlen(s)<=COMPRESS_MAX_STRLEN. */
struct compress_identity
{
ULONG id; /* Identifying number of algorithm. */
ULONG memory; /* Number of bytes of working memory required. */
char *name; /* Name of algorithm. */
char *version; /* Version number. */
char *date; /* Date of release of this version. */
char *copyright; /* Copyright message. */
char *author; /* Author of algorithm. */
char *affiliation; /* Affiliation of author. */
char *vendor; /* Where the algorithm can be obtained. */
};
void lzrw3_compress( /* Single function interface to compression algorithm. */
UWORD action, /* Action to be performed. */
UBYTE *wrk_mem, /* Working memory temporarily given to routine to use. */
UBYTE *src_adr, /* Address of input data. */
LONG src_len, /* Length of input data. */
UBYTE *dst_adr, /* Address of output data. */
void *p_dst_len /* Pointer to a longword where routine will write: */
/* If action=..IDENTITY => Adr of id structure. */
/* If action=..COMPRESS => Length of output data. */
/* If action=..DECOMPRESS => Length of output data. */
);
/******************************************************************************/
/* End of COMPRESS.H */
/******************************************************************************/
/******************************************************************************/
/* fast_copy.h */
/******************************************************************************/
/* This function copies a block of memory very quickly. */
/* The exact speed depends on the relative alignment of the blocks of memory. */
/* PRE : 0<=src_len<=(2^32)-1 . */
/* PRE : Source and destination blocks must not overlap. */
/* POST : MEM[dst_adr,dst_adr+src_len-1]=MEM[src_adr,src_adr+src_len-1]. */
/* POST : MEM[dst_adr,dst_adr+src_len-1] is the only memory changed. */
#define fast_copy(src,dst,len) memcpy(dst,src,len)
/******************************************************************************/
/* End of fast_copy.h */
/******************************************************************************/
#endif
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