/*calcul de la checkSum -> least significant byte de la somme de tous les octets sauf les octets de SYNC */
void calculateCheckSum(struct trame* trameAEnv) {
char* checkSum = (char*) malloc(sizeof (char[2]));
char* lSB = (char*) malloc(sizeof (char[2]));
int sum = 0, i;
memset(lSB, '\0', 2);
for (i = 0; i < 8; i = i + 2) {
checkSum[0] = trameAEnv->DATA[i];
checkSum[1] = trameAEnv->DATA[i + 1];
sum += hexToInt(checkSum);
}
for (i = 0; i < 8; i = i + 2) {
checkSum[0] = trameAEnv->ID[i];
checkSum[1] = trameAEnv->ID[i + 1];
sum += hexToInt(checkSum);
}
checkSum[0] = trameAEnv->HEADER[0];
checkSum[1] = trameAEnv->LENGHT[0];
sum += hexToInt(checkSum);
for (i = 0; i < 2; i = i + 2) {
checkSum[0] = trameAEnv->ORG[i];
checkSum[1] = trameAEnv->ORG[i + 1];
sum += hexToInt(checkSum);
}
for (i = 0; i < 2; i = i + 2) {
checkSum[0] = trameAEnv->STATUS[i];
checkSum[1] = trameAEnv->STATUS[i + 1];
sum += hexToInt(checkSum);
}
itochar(sum, checkSum, 16);
lSB[0] = checkSum[1];
lSB[1] = checkSum[0];
trameAEnv->CHECKSUM = lSB;
free(checkSum);
}
int writePgm(char *fileName, MyImage *image)
{
char parameters_str[5];
int i;
const char *format = "P5";
if (image->flag == 0)
{
return -1;
}
FILE *fp = fopen(fileName, "w");
if (!fp)
{
printf("Unable to open file %s\n", fileName);
return -1;
}
fputs(format, fp);
fputc('\n', fp);
itochar(image->width, parameters_str, 10);
fputs(parameters_str, fp);
parameters_str[0] = 0;
fputc(' ', fp);
itochar(image->height, parameters_str, 10);
fputs(parameters_str, fp);
parameters_str[0] = 0;
fputc('\n', fp);
itochar(image->maxgrey, parameters_str, 10);
fputs(parameters_str, fp);
fputc('\n', fp);
for (i = 0; i < (image->width * image->height); i++)
{
fputc(image->data[i], fp);
}
fclose(fp);
return 0;
}