void undo_command(){
int n;
n =0;
while (strcmp(history[n],"undo\n") != 0){
n++;
}
free(history[n]);
int com,m;
const char *canvas_file = "canvas.txt";
FILE *fp;
if ((fp = fopen(canvas_file, "w")) == NULL) {
fprintf(stderr, "error: cannot open %s.\n", canvas_file);
}
init_canvas();
print_canvas(fp);
for(m = 0; m < n-1; m ++){
com = interpret_command(history[m]);
if(strcmp(history[m],"undo\n") == 0)
break;
}
}
void master()
{
int number_processors;
int count = X_RES; //the number of rows in the image
int row = 0;
MPI_Status status;
MPI_Comm_size(MPI_COMM_WORLD, &number_processors);
int canvas[X_RES][Y_RES];
int color[Y_RES];
//sending tasks to all the processors
for(int i=1; i<number_processors; i++)
{
//send row and slave_id
MPI_Send(&row, 1, MPI_INT, i, DATA_TAG, MPI_COMM_WORLD);
count--;
row++;
printf("%d\n", count);
}
printf("%d\n", count);
//when slaves are idle, then keep sending
do
{
//color contains the values for the row colors
MPI_Recv(color, Y_RES, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
//row is row id in the canvas
MPI_Recv(&row, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
//slave_id is the proccesor that is idle now
//count++;
if(row<X_RES)
{
for(int i=0; i<Y_RES; i++)
{
canvas[row][i] = color[i];
}
MPI_Send(&row, 1, MPI_INT, status.MPI_SOURCE, DATA_TAG, MPI_COMM_WORLD);
count--; //minus one row processed
row++;
printf("%d\n", count);
}
else
{
for(int i=0; i<number_processors; i++)
{
MPI_Send(0, 0, MPI_INT, i, TERMINATE_TAG, MPI_COMM_WORLD);
}
}
}while(count>0);
print_canvas(canvas);
}
int main()
{
int com, n, i;
const char *canvas_file = "canvas.txt";
FILE *fp;
char buf[BUFSIZE];
if ((fp = fopen(canvas_file, "w")) == NULL) {
fprintf(stderr, "error: cannot open %s.\n", canvas_file);
return 1;
}
init_canvas();
print_canvas(fp);
n = 0;
while (1) {
printf("%d > ", n);
fgets(buf, BUFSIZE, stdin);
history[n] = (char*)malloc(sizeof(char) * strlen(buf));
strcpy(history[n], buf);
if (++n >= HISTORY_SIZE) break;
com = interpret_command(buf);
if (com == COM_QUIT) break;
print_canvas(fp);
}
fclose(fp);
if ((fp = fopen("history.txt", "w")) != NULL) {
for (i = 0; i < n; i++)
fprintf(fp, "%s", history[i]);
fclose(fp);
}
}
