code: private static int blockLength(int start, QrMode[] inputMode) {
  
          QrMode mode = inputMode[start];
          int count = 0;
          int i = start;
  
          do {
              count++;
          } while (((i + count) < inputMode.length) && (inputMode[i + count] == mode));
  
          return count;
      }
docs: Find the length of the block starting from 'start'.