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Diffstat (limited to 'drivers/char/ftape/compressor/lzrw3.h')
| -rw-r--r-- | drivers/char/ftape/compressor/lzrw3.h | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/drivers/char/ftape/compressor/lzrw3.h b/drivers/char/ftape/compressor/lzrw3.h new file mode 100644 index 000000000..533feba47 --- /dev/null +++ b/drivers/char/ftape/compressor/lzrw3.h @@ -0,0 +1,253 @@ +#ifndef _LZRW3_H +#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 |