implement MurmurHash closes #76

src/main/scala/com/github/mogproject/redismock/util/EnhancedByte.scala

@@ -9,7 +9,9 @@ package com.github.mogproject.redismock.util
 class EnhancedByte(x: Byte) {
 
   /** Convert to unsigned integer */
-  def toUnsignedInt: Int = (x.toInt + 256) % 256
+  def toUnsignedInt: Int = x & 0xff
+
+  def toUnsignedLong: Long = toUnsignedInt.toLong
 
   /** Count the number of 1-bit */
   def popCount: Int = {

src/main/scala/com/github/mogproject/redismock/util/MurmurHash.scala

@@ -0,0 +1,25 @@
+package com.github.mogproject.redismock.util
+
+import com.github.mogproject.redismock.util.Implicits._
+
+
+object MurmurHash {
+
+  private val defaultSeed = 0xadc83b19L
+
+  def murmurHash64A(data: Seq[Byte], seed: Long = defaultSeed): Long = {
+    val m = 0xc6a4a7935bd1e995L
+    val r = 47
+
+    val f: Long => Long = m.*
+    val g: Long => Long = x => x ^ (x >>> r)
+
+    val h = data.grouped(8).foldLeft(seed ^ f(data.length)) { case (y, xs) =>
+      val k = xs.foldRight(0L)((b, x) => (x << 8) + b.toUnsignedLong)
+      val j: Long => Long = if (xs.length == 8) f compose g compose f else identity
+      f(y ^ j(k))
+    }
+    (g compose f compose g)(h)
+  }
+
+}

src/test/scala/com/github/mogproject/redismock/util/MurmurHashSpec.scala

@@ -0,0 +1,23 @@
+package com.github.mogproject.redismock.util
+
+import org.scalatest.{BeforeAndAfterAll, BeforeAndAfterEach, Matchers, FunSpec}
+
+
+class MurmurHashSpec extends FunSpec with Matchers with BeforeAndAfterEach with BeforeAndAfterAll {
+  describe("HashUtil#murmurHash64A") {
+    it("should return 64 bit value") {
+      MurmurHash.murmurHash64A("A".getBytes) shouldBe 0xfc089b66b14af040L
+      MurmurHash.murmurHash64A("AB".getBytes) shouldBe 0x24fb508dc42efb7fL
+      MurmurHash.murmurHash64A("B".getBytes) shouldBe 0x130dd9603dcd32a4L
+      MurmurHash.murmurHash64A("BA".getBytes) shouldBe 0x25cbc673105b365dL
+
+      MurmurHash.murmurHash64A("".getBytes) shouldBe 0xd8dfea6585bc9732L
+      MurmurHash.murmurHash64A("ABCDEFGHabcdefg".getBytes) shouldBe 0x3dfb8e09231eeb32L
+      MurmurHash.murmurHash64A("ABCDEFGHabcdefgh".getBytes) shouldBe 0x40055074d92b389fL
+      MurmurHash.murmurHash64A("ABCDEFGHabcdefghi".getBytes) shouldBe 0xd298ffe6aa77babeL
+
+      MurmurHash.murmurHash64A(Seq.fill[Byte](100)(0)) shouldBe 0xc9450ffd5a7bf9ccL
+      MurmurHash.murmurHash64A(Seq.fill[Byte](100)(-1)) shouldBe 0x78be0c4f11cdc6d5L
+    }
+  }
+}