function createCrcTable() {
  const crcTable = [];
  for (let n = 0; n < 256; n += 1) {
    let c = n;
    for (let k = 0; k < 8; k += 1) {
      c = ((c & 1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
    }
    crcTable[n] = c;
  }

  return crcTable;
}
Create the initial CRC table needed to calculate the checksums.

@return {number[]} An array containing hashes.