code: public int alloc(int size) {
          int index = n;
          int len = array.length;
          if (n + size >= len) {
              byte[] aux = new byte[len + blockSize];
              System.arraycopy(array, 0, aux, 0, len);
              array = aux;
          }
          n += size;
          return index;
      }
docs: This is to implement memory allocation in the array. Like malloc().