buffer = malloc(WINDOW_SIZE);
while((c = read(f_src, buffer, WINDOW_SIZE)) > 0) razf_write(rz, buffer, c);
razf_close(rz); // f_dst will be closed here
buffer = malloc(WINDOW_SIZE);
while((c = read(f_src, buffer, WINDOW_SIZE)) > 0) razf_write(rz, buffer, c);
razf_close(rz); // f_dst will be closed here