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/******************************************************************************/
/* Start of crctable.c */
/******************************************************************************/
/* */
/* Author : Ross Williams (ross@guest.adelaide.edu.au.). */
/* Date : 3 June 1993. */
/* Version : 1.0. */
/* Status : Public domain. */
/* */
/* Description : This program writes a CRC lookup table (suitable for */
/* inclusion in a C program) to a designated output file. The program can be */
/* statically configured to produce any table covered by the Rocksoft^tm */
/* Model CRC Algorithm. For more information on the Rocksoft^tm Model CRC */
/* Algorithm, see the document titled "A Painless Guide to CRC Error */
/* Detection Algorithms" by Ross Williams (ross@guest.adelaide.edu.au.). This */
/* document is likely to be in "ftp.adelaide.edu.au/pub/rocksoft". */
/* */
/* Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia. */
/* */
/******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include "crcmodel.h"
/******************************************************************************/
/* TABLE PARAMETERS */
/* ================ */
/* The following parameters entirely determine the table to be generated. You */
/* should need to modify only the definitions in this section before running */
/* this program. */
/* */
/* TB_FILE is the name of the output file. */
/* TB_WIDTH is the table width in bytes (either 2 or 4). */
/* TB_POLY is the "polynomial", which must be TB_WIDTH bytes wide. */
/* TB_REVER indicates whether the table is to be reversed (reflected). */
/* */
/* Example: */
/* */
/* #define TB_FILE "crctable.out" */
/* #define TB_WIDTH 2 */
/* #define TB_POLY 0x8005L */
/* #define TB_REVER TRUE */
#define TB_FILE "crctable.out"
#define TB_WIDTH 4
#define TB_POLY 0x04C11DB7L
#define TB_REVER TRUE
/******************************************************************************/
/* Miscellaneous definitions. */
#define LOCAL static
FILE *outfile;
#define WR(X) fprintf(outfile,(X))
#define WP(X,Y) fprintf(outfile,(X),(Y))
/******************************************************************************/
LOCAL void chk_err P_((char *));
LOCAL void chk_err (mess)
/* If mess is non-empty, write it out and abort. Otherwise, check the error */
/* status of outfile and abort if an error has occurred. */
char *mess;
{
if (mess[0] != 0 ) {printf("%s\n",mess); exit(EXIT_FAILURE);}
if (ferror(outfile)) {perror("chk_err"); exit(EXIT_FAILURE);}
}
/******************************************************************************/
LOCAL void chkparam P_((void));
LOCAL void chkparam ()
{
if ((TB_WIDTH != 2) && (TB_WIDTH != 4))
chk_err("chkparam: Width parameter is illegal.");
if ((TB_WIDTH == 2) && (TB_POLY & 0xFFFF0000L))
chk_err("chkparam: Poly parameter is too wide.");
if ((TB_REVER != FALSE) && (TB_REVER != TRUE))
chk_err("chkparam: Reverse parameter is not boolean.");
}
/******************************************************************************/
LOCAL void gentable P_((void));
LOCAL void gentable ()
{
WR("/*****************************************************************/\n");
WR("/* */\n");
WR("/* CRC LOOKUP TABLE */\n");
WR("/* ================ */\n");
WR("/* The following CRC lookup table was generated automagically */\n");
WR("/* by the Rocksoft^tm Model CRC Algorithm Table Generation */\n");
WR("/* Program V1.0 using the following model parameters: */\n");
WR("/* */\n");
WP("/* Width : %1lu bytes. */\n",
(ulong) TB_WIDTH);
if (TB_WIDTH == 2)
WP("/* Poly : 0x%04lX */\n",
(ulong) TB_POLY);
else
WP("/* Poly : 0x%08lXL */\n",
(ulong) TB_POLY);
if (TB_REVER)
WR("/* Reverse : TRUE. */\n");
else
WR("/* Reverse : FALSE. */\n");
WR("/* */\n");
WR("/* For more information on the Rocksoft^tm Model CRC Algorithm, */\n");
WR("/* see the document titled \"A Painless Guide to CRC Error */\n");
WR("/* Detection Algorithms\" by Ross Williams */\n");
WR("/* (ross@guest.adelaide.edu.au.). This document is likely to be */\n");
WR("/* in the FTP archive \"ftp.adelaide.edu.au/pub/rocksoft\". */\n");
WR("/* */\n");
WR("/*****************************************************************/\n");
WR("\n");
switch (TB_WIDTH)
{
case 2: WR("unsigned short crctable[256] =\n{\n"); break;
case 4: WR("unsigned long crctable[256] =\n{\n"); break;
default: chk_err("gentable: TB_WIDTH is invalid.");
}
chk_err("");
{
int i;
cm_t cm;
char *form = (TB_WIDTH==2) ? "0x%04lX" : "0x%08lXL";
int perline = (TB_WIDTH==2) ? 8 : 4;
cm.cm_width = TB_WIDTH*8;
cm.cm_poly = TB_POLY;
cm.cm_refin = TB_REVER;
for (i=0; i<256; i++)
{
WR(" ");
WP(form,(ulong) cm_tab(&cm,i));
if (i != 255) WR(",");
if (((i+1) % perline) == 0) WR("\n");
chk_err("");
}
WR("};\n");
WR("\n");
WR("/*****************************************************************/\n");
WR("/* End of CRC Lookup Table */\n");
WR("/*****************************************************************/\n");
WR("");
chk_err("");
}
}
/******************************************************************************/
main ()
{
printf("\n");
printf("Rocksoft^tm Model CRC Algorithm Table Generation Program V1.0\n");
printf("-------------------------------------------------------------\n");
printf("Output file is \"%s\".\n",TB_FILE);
chkparam();
outfile = fopen(TB_FILE,"w"); chk_err("");
gentable();
if (fclose(outfile) != 0)
chk_err("main: Couldn't close output file.");
printf("\nSUCCESS: The table has been successfully written.\n");
}
/******************************************************************************/
/* End of crctable.c */
/******************************************************************************/
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