code: private static int[] make_crc_table() {
          int[] crc_table = new int[256];
          for (int n = 0; n < 256; n++) {
              int c = n;
              for (int k = 8; --k >= 0; ) {
                  if ((c & 1) != 0)
                      c = 0xedb88320 ^ (c >>> 1);
                  else
                      c = c >>> 1;
              }
              crc_table[n] = c;
          }
          return crc_table;
      }
docs: Make the table for a fast CRC.