Function x64hash128

src/utils/hashing.ts:162–301

(input: string, seed?: number)

 * Benchmark https://jsbench.me/p4lkpaoabi/1
 */
export function x64hash128(input: string, seed?: number): string {
  const key = getUTF8Bytes(input)
  seed = seed || 0
  const length = [0, key.length]
  const remainder = length[1] % 16
  const bytes = length[1] - remainder
  const h1 = [0, seed]
  const h2 = [0, seed]
  const k1 = [0, 0]
  const k2 = [0, 0]

  let i: number
  for (i = 0; i < bytes; i = i + 16) {
    k1[0] = key[i + 4] | (key[i + 5] << 8) | (key[i + 6] << 16) | (key[i + 7] << 24)
    k1[1] = key[i] | (key[i + 1] << 8) | (key[i + 2] << 16) | (key[i + 3] << 24)
    k2[0] = key[i + 12] | (key[i + 13] << 8) | (key[i + 14] << 16) | (key[i + 15] << 24)
    k2[1] = key[i + 8] | (key[i + 9] << 8) | (key[i + 10] << 16) | (key[i + 11] << 24)

    x64Multiply(k1, C1)
    x64Rotl(k1, 31)
    x64Multiply(k1, C2)
    x64Xor(h1, k1)
    x64Rotl(h1, 27)
    x64Add(h1, h2)
    x64Multiply(h1, M)
    x64Add(h1, N1)
    x64Multiply(k2, C2)
    x64Rotl(k2, 33)
    x64Multiply(k2, C1)
    x64Xor(h2, k2)
    x64Rotl(h2, 31)
    x64Add(h2, h1)
    x64Multiply(h2, M)
    x64Add(h2, N2)
  }
  k1[0] = 0
  k1[1] = 0
  k2[0] = 0
  k2[1] = 0
  const val = [0, 0]
  switch (remainder) {
    case 15:
      val[1] = key[i + 14]
      x64LeftShift(val, 48)
      x64Xor(k2, val)
    // fallthrough
    case 14:
      val[1] = key[i + 13]
      x64LeftShift(val, 40)
      x64Xor(k2, val)
    // fallthrough
    case 13:
      val[1] = key[i + 12]
      x64LeftShift(val, 32)
      x64Xor(k2, val)
    // fallthrough
    case 12:
      val[1] = key[i + 11]