crc4tab.c

Error checking CRC and CRC TABLE GENERATORS in C Language

#include <stdio.h>

#define POLINOMIO 0x3

int main()
{
	FILE *fp;
	unsigned char 	c, k, crc;

	if((fp=fopen("crc4.txt", "wr"))==NULL)
	{
		printf("ERRO AO ABRIR O ARQUIVO");
		return 1;
	}

	fprintf(fp, "crc4[16] = {");
	for(c=0;c<16;c++)
	{
		crc=c;
		for(k=0;k<4;k++)
		{
			if(crc&8)
			{
				crc=(crc<<1)&0xf;
				crc^=POLINOMIO;
			}
			else crc=(crc<<1)&0xf;
		}
		if(!(c%4)) fprintf(fp, "\n");
		if(c!=15) fprintf(fp, "%d, ", crc);
		else fprintf(fp, "%d };", crc);
	}
	fclose(fp);

	return 0;
}