| #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 |
