Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

109 lines (89 sloc) 2.741 kb
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
namespace Enyim
{
/// <summary>
/// This is Jenkin's "One at A time Hash".
/// http://en.wikipedia.org/wiki/Jenkins_hash_function
///
/// Coming from libhashkit.
/// </summary>
/// <remarks>Does not support block based hashing.</remarks>
internal class HashkitOneAtATime : HashAlgorithm, IUIntHashAlgorithm
{
public HashkitOneAtATime()
{
this.HashSizeValue = 32;
}
public override bool CanTransformMultipleBlocks
{
get { return false; }
}
public override void Initialize() { }
protected override void HashCore(byte[] array, int ibStart, int cbSize)
{
if (array == null) throw new ArgumentNullException("array");
if (ibStart < 0 || ibStart > array.Length) throw new ArgumentOutOfRangeException("ibStart");
if (ibStart + cbSize > array.Length) throw new ArgumentOutOfRangeException("cbSize");
HashkitOneAtATime.UnsafeHashCore(array, ibStart, cbSize);
}
protected override byte[] HashFinal()
{
return BitConverter.GetBytes(this.CurrentHash);
}
public uint CurrentHash { get; private set; }
#region [ UnsafeHashCore ]
// see the murmur hash about stream support
private static unsafe uint UnsafeHashCore(byte[] data, int offset, int count)
{
uint hash = 0;
fixed (byte* start = &(data[offset]))
{
var ptr = start;
while (count > 0)
{
hash += *ptr;
hash += (hash << 10);
hash ^= (hash >> 6);
count--;
ptr++;
}
}
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return hash;
}
#endregion
#region [ IUIntHash ]
uint IUIntHashAlgorithm.ComputeHash(byte[] data)
{
this.Initialize();
this.HashCore(data, 0, data.Length);
return this.CurrentHash;
}
#endregion
}
}
#region [ License information ]
/* ************************************************************
*
* Copyright (c) 2010 Attila Kiskó, enyim.com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* ************************************************************/
#endregion
Jump to Line
Something went wrong with that request. Please try again.