dotty.tools.tasty.TastyHash.scala Maven / Gradle / Ivy

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package dotty.tools.tasty

object TastyHash {

  /** Returns a non-cryptographic 64-bit hash of the array.
   *
   *  from https://en.wikipedia.org/wiki/PJW_hash_function#Algorithm
   */
  def pjwHash64(data: Array[Byte], length: Int): Long = {
    var h = 0L
    var i = 0
    while (i < length) {
      val d = data(i) & 0xFFL // Interpret byte as unsigned byte
      h = (h << 8) + d
      val high = h & 0xFF00000000000000L
      h ^= high >>> 48L
      h &= ~high
      i += 1
    }
    h
  }
  def pjwHash64(data: Array[Byte]): Long =
    pjwHash64(data, data.length)
}