#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 #include /******************************************************************************/ /* */ /* 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