Clean up some of the has sum computing.

Author: mattlorimor

ProbabilisticDataStructures/CuckooBloomFilter.cs

@@ -363,7 +363,7 @@ private bool Insert(uint i1, uint i2, byte[] f)
  var tempF = f;
  f = this.Buckets[bucketIdx][entryIdx];
  this.Buckets[bucketIdx][entryIdx] = tempF;
- i = i ^ ProbabilisticDataStructures.ToBigEndianUInt32(this.ComputeHash(f));
+ i = i ^ ComputeHashSum32(f);
  var b = this.Buckets[i % this.M];
 
  idx = GetEmptyEntry(b);
@@ -389,8 +389,8 @@ private Components GetComponents(byte[] data)
  {
  var hash = this.ComputeHash(data);
  var f = hash.Take((int)this.F).ToArray();
- var i1 = ProbabilisticDataStructures.ToBigEndianUInt32(hash);
- var i2 = ProbabilisticDataStructures.ToBigEndianUInt32(this.ComputeHash(f));
+ var i1 = this.ComputeHashSum32(hash);
+ var i2 = this.ComputeHashSum32(f);
 
  return Components.Create(f, i1, i2);
  }
@@ -408,6 +408,19 @@ private byte[] ComputeHash(byte[] data)
  return sum;
  }
 
+ /// <summary>
+ /// Returns the sum of the hash.
+ /// </summary>
+ /// <param name="data">Data</param>
+ /// <returns>32-bit hash value</returns>
+ private uint ComputeHashSum32(byte[] data)
+ {
+ var hash = new Hash(this.Hash);
+ hash.ComputeHash(data);
+ var sum = hash.Sum();
+ return ProbabilisticDataStructures.ToBigEndianUInt32(sum);
+ }
+
  /// <summary>
  /// Returns the optimal fingerprint length in bytes for the given bucket size and
  /// false-positive rate epsilon.

ProbabilisticDataStructures/ProbabilisticDataStructures.cs

@@ -55,6 +55,15 @@ public static HashKernelReturnValue HashKernel(byte[] data, HashAlgorithm algori
  );
  }
 
+ /// <summary>
+ /// Returns the default hashing algorithm for the library.
+ /// </summary>
+ /// <returns>The default hashing algorithm for the library</returns>
+ internal static HashAlgorithm GetDefaultHashAlgorithm()
+ {
+ return HashAlgorithm.Create("MD5");
+ }
+
  public static uint ToBigEndianUInt32(byte[] bytes)
  {
  if (BitConverter.IsLittleEndian)