117 lines
3.4 KiB
C#
117 lines
3.4 KiB
C#
//Copyright (c) 2007-2008 Henrik Schröder, Oliver Kofoed Pedersen
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//Permission is hereby granted, free of charge, to any person
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//obtaining a copy of this software and associated documentation
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//files (the "Software"), to deal in the Software without
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//restriction, including without limitation the rights to use,
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//copy, modify, merge, publish, distribute, sublicense, and/or sell
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//copies of the Software, and to permit persons to whom the
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//Software is furnished to do so, subject to the following
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//conditions:
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//The above copyright notice and this permission notice shall be
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//included in all copies or substantial portions of the Software.
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//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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//EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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//OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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//NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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//HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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//WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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//FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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//OTHER DEALINGS IN THE SOFTWARE.
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using System;
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using System.Security.Cryptography;
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namespace CYQ.Data.Cache
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{
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/// <summary>
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/// Fowler-Noll-Vo hash, variant 1, 32-bit version.
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/// http://www.isthe.com/chongo/tech/comp/fnv/
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/// </summary>
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internal class FNV1_32 : HashAlgorithm
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{
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private static readonly uint FNV_prime = 16777619;
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private static readonly uint offset_basis = 2166136261;
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protected uint hash;
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public FNV1_32()
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{
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HashSizeValue = 32;
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}
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public override void Initialize()
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{
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hash = offset_basis;
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}
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protected override void HashCore(byte[] array, int ibStart, int cbSize)
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{
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int length = ibStart + cbSize;
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for (int i = ibStart; i < length; i++)
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{
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hash = (hash * FNV_prime) ^ array[i];
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}
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}
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protected override byte[] HashFinal()
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{
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return BitConverter.GetBytes(hash);
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}
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}
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/// <summary>
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/// Fowler-Noll-Vo hash, variant 1a, 32-bit version.
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/// http://www.isthe.com/chongo/tech/comp/fnv/
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/// </summary>
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internal class FNV1a_32 : HashAlgorithm
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{
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private static readonly uint FNV_prime = 16777619;
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private static readonly uint offset_basis = 2166136261;
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protected uint hash;
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public FNV1a_32()
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{
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HashSizeValue = 32;
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}
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public override void Initialize()
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{
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hash = offset_basis;
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}
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protected override void HashCore(byte[] array, int ibStart, int cbSize)
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{
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int length = ibStart + cbSize;
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for (int i = ibStart; i < length; i++)
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{
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hash = (hash ^ array[i]) * FNV_prime;
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}
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}
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protected override byte[] HashFinal()
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{
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return BitConverter.GetBytes(hash);
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}
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}
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/// <summary>
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/// Modified Fowler-Noll-Vo hash, 32-bit version.
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/// http://home.comcast.net/~bretm/hash/6.html
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/// </summary>
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internal class ModifiedFNV1_32 : FNV1_32
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{
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protected override byte[] HashFinal()
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{
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hash += hash << 13;
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hash ^= hash >> 7;
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hash += hash << 3;
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hash ^= hash >> 17;
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hash += hash << 5;
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return BitConverter.GetBytes(hash);
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}
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}
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} |