view ostc4pack/src/checksum_final_add_fletcher.cpp @ 474:4be72d55b09a Improve_Button_Sleep

Added error detection for reading of ADC values in sleep mode: ADC value were used for pressure calculation without making sure that the I2C operations used for reading the values were called successfully. As result a invalid pressure could be calculated causing the OSTC to wakeup or (worstcase) to enter dive mode. To avoid this the return values are now evaluated and pressure calculation is only done if I2C signaled no error during transmission
author ideenmodellierer
date Tue, 12 May 2020 22:42:52 +0200
parents 1e707b34667e
children 01f40cb1057e
line wrap: on
line source

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

void fletcher16(unsigned char *result1, unsigned char *result2, unsigned char const *data, size_t bytes )
{
        unsigned short sum1 = 0xff, sum2 = 0xff;
        size_t tlen;
 
        while (bytes) {
                tlen = bytes >= 20 ? 20 : bytes;
                bytes -= tlen;
                do {
                        sum2 += sum1 += *data++;
                } while (--tlen);
                sum1 = (sum1 & 0xff) + (sum1 >> 8);
                sum2 = (sum2 & 0xff) + (sum2 >> 8);
        }
        /* Second reduction step to reduce sums to 8 bits */
        sum1 = (sum1 & 0xff) + (sum1 >> 8);
        sum2 = (sum2 & 0xff) + (sum2 >> 8);
        *result2 = (sum2 & 0xff);
        *result1 = (sum1 & 0xff);
//        return sum2 << 8 | sum1;
}


// This is a variant of fletcher16 with a 16 bit sum instead of an 8 bit sum,
// and modulo 2^16 instead of 2^16-1
void
hw_ostc3_firmware_checksum (unsigned char *result1, unsigned char *result2, unsigned char *result3, unsigned char *result4, unsigned char const *data, size_t bytes )
{
	unsigned short low = 0;
	unsigned short high = 0;
	for (unsigned int i = 0; i < bytes; i++) {
		low  += data[i];
		high += low;
	}
        *result1 = (low & 0xff);
        *result2 = (low/256 & 0xff);
        *result3 = (unsigned char)(high & 0xff);
        *result4 = (unsigned char)((high/256) & 0xff);
//	return (((unsigned int)high) << 16) + low;
}


int main(int argc, char** argv) {
	
	
	FILE *fp, * fpout;
	size_t lenTotal,lenTemp;
	unsigned char buf[2000000];
	char *file = argv[1];
	char *file2 =  argv[2];
	char *file3 =  argv[3];
	unsigned int pruefsumme;
	unsigned char buf2[4];

   	printf("1: %s\n",  file);
   	printf("2: %s\n",  file2);
   	printf("3: %s\n",  file3);
   	printf("\n");
     
	
		//write File with length and cheksum
	char filename[500], filenameout[510] ;
	sprintf(filename,"%s",file);
	int filelength = strlen(filename);
	filename[filelength -4] = 0;
	
	lenTotal = 0;
	if (NULL == (fp = fopen(file, "rb")))
	{
	    printf("Unable to open %s for reading\n", file);
	    return -1;
	}
	lenTemp = fread(&buf[lenTotal], sizeof(char), sizeof(buf), fp);
//	lenTemp = fread(buf, sizeof(char), sizeof(buf), fp);
	lenTotal = lenTemp;
	printf("%d bytes read (hex: %#x )\n", lenTemp,lenTemp);
	fclose(fp);

	if(file2)
	{
		if (NULL == (fp = fopen(file2, "rb")))
		{
		    printf("Unable to open %s for reading\n", file2);
		    return -1;
		}
		lenTemp = fread(&buf[lenTotal], sizeof(char), sizeof(buf)-lenTotal, fp);
		lenTotal += lenTemp;
		printf("%d bytes read (hex: %#x )\n", lenTemp,lenTemp);
		fclose(fp);
	}
	if(file3)
	{
		if (NULL == (fp = fopen(file3, "rb")))
		{
		    printf("Unable to open %s for reading\n", file3);
		    return -1;
		}
		lenTemp = fread(&buf[lenTotal], sizeof(char), sizeof(buf)-lenTotal, fp);
		lenTotal += lenTemp;
		printf("%d bytes read (hex: %#x )\n", lenTemp,lenTemp);
		fclose(fp);
	}

   	printf("\n");
	printf("%d bytes read (hex: %#x ) total \n", lenTotal,lenTotal);

	time_t rawtime;
	time (&rawtime);
	struct tm *timeinfo;
	timeinfo = localtime(&rawtime);
	
//	sprintf(filenameout,"fwupdate_%s.bin",ctime(&rawtime));
	sprintf(filenameout,"OSTC4update_%02u%02u%02u.bin",timeinfo->tm_year-100,timeinfo->tm_mon+1,timeinfo->tm_mday);

    fpout = fopen(filenameout, "wb");     
    for(int i = 0;i <lenTotal;i++)
    {
    	if(fwrite(&buf[i],1,1,fpout) != 1)
     	printf("error writing\n");
	}
	
	hw_ostc3_firmware_checksum(&buf2[0],&buf2[1],&buf2[2],&buf2[3],buf,lenTotal);
	printf("checksum  %#x %#x %#x %#x\n", buf2[0],buf2[1], buf2[2], buf2[3]);
   	if(fwrite(&buf2[0],1,4,fpout) != 4)
    	printf("error writing checksum\n");
    ;
	fclose(fpout);
}