UltimateZoneBuilder/Source/Core/General/MurmurHash2.cs
MaxED 77d2a15f7f Changed: when entering Visual mode, the camera is no longer positioned at "Visual Mode camera" thing when "Sync camera position between 2D and 3D mode" setting is enabled.
Changed: Visplane Explorer plugin is now initialized only in Doom/Hexen map formats.
Fixed, Visual mode: thing cages were not rendered when things didn't have a sprite.
Fixed, Internal, DB2 bug: Plug.Dispose() was never called.
2015-10-09 21:57:32 +00:00

109 lines
3.1 KiB
C#

#region ============== License
/***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is HashTableHashing.MurmurHash2.
*
* The Initial Developer of the Original Code is
* Davy Landman.
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#endregion
using System;
using System.Text;
namespace CodeImp.DoomBuilder
{
public static class MurmurHash2
{
private const UInt32 m = 0x5bd1e995;
private const Int32 r = 24;
public static UInt32 Hash(string data)
{
return Hash(Encoding.ASCII.GetBytes(data), 0xc58f1a7b);
}
private static unsafe UInt32 Hash(Byte[] data, UInt32 seed)
{
Int32 length = data.Length;
if(length == 0) return 0;
UInt32 h = seed ^ (UInt32)length;
Int32 remainingBytes = length & 3; // mod 4
Int32 numberOfLoops = length >> 2; // div 4
fixed(byte* firstByte = &(data[0]))
{
UInt32* realData = (UInt32*)firstByte;
while(numberOfLoops != 0)
{
UInt32 k = *realData;
k *= m;
k ^= k >> r;
k *= m;
h *= m;
h ^= k;
numberOfLoops--;
realData++;
}
switch(remainingBytes)
{
case 3:
h ^= (UInt16)(*realData);
h ^= ((UInt32)(*(((Byte*)(realData)) + 2))) << 16;
h *= m;
break;
case 2:
h ^= (UInt16)(*realData);
h *= m;
break;
case 1:
h ^= *((Byte*)realData);
h *= m;
break;
}
}
// Do a few final mixes of the hash to ensure the last few
// bytes are well-incorporated.
h ^= h >> 13;
h *= m;
h ^= h >> 15;
return h;
}
}
}